# P40 Vs all other fighters in Europe



## denny (Jan 5, 2022)

What was lacking in the P-40 that made the Allies decide not to upgrade it with a Merlin Engine.?
Or maybe it was done and the P-40 proved wanting in some area(s).?
Thank You

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## fastmongrel (Jan 5, 2022)

The P40 did get a Merlin (actually a Packard v1650). Look up the P40-F and L variants.

It always suffered from being a year behind its contemporaries a P40 from the Mediterranean theatre in late 1941 would have been a killer aircraft over Britain a year earlier. Not that it was a bad fighter iirc over 200 Allied pilots became an ace in one and it was a very sturdy bird that could take a lot of punishment.

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## tomo pauk (Jan 5, 2022)

P-40 never gotten the 2-stage supercharged Merlin. Short supply of these engines meant that only Spitfire, Mosquito and Mustang flew with them in meaningful numbers in ww2.


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## EwenS (Jan 5, 2022)

tomo pauk said:


> P-40 never gotten the 2-stage supercharged Merlin. Short supply of these engines meant that only Spitfire, Mosquito and Mustang flew with them in meaningful numbers in ww2.



By the time Packard started production of the 2 stage supercharged Merlin engine in May 1943 it was being reserved for the P-51B/C Mustang. Production of the Merlin powered P-40F/L line had ceased several months, if not nearly a year previously. Allison by then was producing more than enough of more powerful variants of the V-1710 motor to keep everyone happy.

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## PAT303 (Jan 5, 2022)

The P 40 doesn't get the attention it deserves, like the Wildcat its overshadowed by the P 51 and Hellcat.

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## Shortround6 (Jan 5, 2022)

denny said:


> What was lacking in the P-40 that made the Allies decide not to upgrade it with a Merlin Engine.?
> Or maybe it was done and the P-40 proved wanting in some area(s).?
> Thank You



This covers a lot of area/time. 


EwenS said:


> Production of the Merlin powered P-40F/L line had ceased several months, if not nearly a year previously. Allison by then was producing more than enough of more powerful variants of the V-1710 motor to keep everyone happy.


Actually the P-40Ls were produced from Jan 1943 to April of 1943. 
Allison was not producing enough more powerful engines. The 1943 engines had about 4,000ft more altitude than the 1942 engines. Change over was actually at the end of Nov 1942 with the P-40M model. But 15,000-15,500 altitude for an 1150hp engine wasn't good enough for a general purpose fighter in 1943. It was good enough to fill in and it was good for low altitude work. 

The P-40 could be improved but it was going to take a lot of work and it wasn't going to be as good as the P-51B.

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## spicmart (Jan 5, 2022)

As I understood the main reasons it could not compete with the P-51 were inferior range and worse aerodynamics when using the same engines.
Wasn't it possible to install large enough tanks to make it a long range escort fighter?

I wonder how it would have performed when a Rolls Royce Griffon engine had been installed to make the P-40 a point-defense interceptor in the vein of the Spitfire Mk 14. 
The aerodynamics were not worse than the Spitfire's and the weight was not much higher.
Guess it could compete with the Spit 14 and the Dora-9


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## varsity07840 (Jan 5, 2022)

Shortround6 said:


> This covers a lot of area/time.
> 
> Actually the P-40Ls were produced from Jan 1943 to April of 1943.
> Allison was not producing enough more powerful engines. The 1943 engines had about 4,000ft more altitude than the 1942 engines. Change over was actually at the end of Nov 1942 with the P-40M model. But 15,000-15,500 altitude for an 1150hp engine wasn't good enough for a general purpose fighter in 1943. It was good enough to fill in and it was good for low altitude work.
> ...


The P-40 was a very heavy aircraft with an obsolete airframe. The 2 stage 2 speed Merlin would have bettered its altitude performance but increased the weight at the same time thus mitigating the performance increase. Climb rate probably would not have been significantly improved. The P-51D was not a great climber. Range would have remained too short for escort missions. So, why bother with further development? Development funds be better spent on the P-38K.

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## pbehn (Jan 5, 2022)

Th P-51 was designed to be better than the P-40 and others and it was. By 1943 in Europe N Africa the theatres that planes could be used in was diminishing. You could make a better P-40 with a two stage Packard (Merlin) but it wouldnt be as good as a P-51 so it would be a waste of engines and P-51 fuselages which were waiting for engines.

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## SaparotRob (Jan 5, 2022)

The Mustang was offered to the British Purchasing Commission by NAA as something better. It was.

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## pbehn (Jan 5, 2022)

SaparotRob said:


> The Mustang was offered to the British Purchasing Commission by NAA as something better. It was.


Sometimes not having a contract is an advantage, the P-51 could incorporate British requests before production started, The P-39 and P-40 were already in late design or production which makes things a whole lot more difficult.

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## denny (Jan 5, 2022)

Thanks for all the replies....I Appreciate It

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## BiffF15 (Jan 5, 2022)

varsity07840 said:


> The P-40 was a very heavy aircraft with an obsolete airframe. The 2 stage 2 speed Merlin would have bettered its altitude performance but increased the weight at the same time thus mitigating the performance increase. Climb rate probably would not have been significantly improved. The P-51D was not a great climber. Range would have remained too short for escort missions. So, why bother with further development? Development funds be better spent on the P-38K.


While the P-51D wasn't a great climber compared to it's peer Spit, 109 or 190, it could however fly from bases in the UK to Berlin, fight for 20 minutes, and fly back (something even the vaulted P-39 couldn't do). What it didn't have in climb it more than made up for with aerodynamics / fuel load that gave it unbelievable range.

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## pbehn (Jan 5, 2022)

BiffF15 said:


> While the P-51D wasn't a great climber compared to it's peer Spit, 109 or 190, it could however fly from bases in the UK to Berlin, fight for 20 minutes, and fly back (something even the vaulted P-39 couldn't do). What it didn't have in climb it more than made up for with aerodynamics / fuel load that gave it unbelievable range.


The P-51 did its climbing early, it was already up there.

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## Glue Sniffer (Jan 5, 2022)

The P-40 is in my honest opinion the most under rated fighter in the entire war...and there were lots of under rated fighter...F4F anyone? Considering it held the line before the war even started...its kill ratio is amazing...and it was flown against other nations at their peak by inexperienced American airmen unlike the P-51D that got to hold the trophy after the p-47 and Spitfires had already demolished the Luftwaffe. 

The P-40 was not great at altitude...but it was an absolute workhorse and could turn better than most would think. Its not fair to compare a 1930s design to a 1945 design...just like it not fair to compare a king tiger against a M4a1 or T34

It never ceases to amaze me how we can glorify the Hurricane and yet badmouth the P40. Both great aircraft for the record.

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## Glue Sniffer (Jan 5, 2022)

"While the P-51D wasn't a great climber compared to it's peer Spit, 109 or 190, it could however fly from bases in the UK to Berlin, fight for 20 minutes, and fly back (something even the vaulted P-39 couldn't do). What it didn't have in climb it more than made up for with aerodynamics / fuel load that gave it unbelievable range."

Agree completely


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## pbehn (Jan 5, 2022)

Glue Sniffer said:


> It never ceases to amaze me how we can glorify the Hurricane and yet badmouth the P40. Both great aircraft for the record.


I dont think many do. Although the P-40 was a better aircraft the difference is in time. In 1939 it was the only allied fighter in Europe in numbers. Without it the Battles of France, Britain and Malta could not be fought in the air and North Africa without it would have been hard work if not complete disaster waiting for the P-40 and Spitfire to arrive.

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## tomo pauk (Jan 5, 2022)

Glue Sniffer said:


> The P-40 is in my honest opinion the most under rated fighter in the entire war...and there were lots of under rated fighter...F4F anyone? Considering it held the line before the war even started...its kill ratio is amazing...and it was flown against other nations at their peak by inexperienced American airmen unlike the P-51D that got to hold the trophy after the p-47 and Spitfires had already demolished the Luftwaffe.
> 
> The P-40 was not great at altitude...but it was an absolute workhorse and could turn better than most would think. Its not fair to compare a 1930s design to a 1945 design...just like it not fair to compare a king tiger against a M4a1 or T34
> 
> It never ceases to amaze me how we can glorify the Hurricane and yet badmouth the P40. Both great aircraft for the record.


P-40 gets the fair shake on this forum IMO. At least it does not get compared with designs from 1945, people mostly compare it with Spitfire, Bf 109, Zero, P-51, P-39 and/or Fw 190. What crystalizes at the end was that P-40 lacked a good engine in order to be comparable vs. the best the West had; against the Zero it was just fine. The speed and rate of climb were a bigger asset than the turning abilities in the ww2.
Unfortunately, there was no P-40s holding any lines before the war started, the 1st combat use was probably in the winter of 1940/41?

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## Glue Sniffer (Jan 5, 2022)

You're correct...I was speaking from a strictly American prospective in regards to "holding the line". I would do well to remember that war was happening prior to US entry. Our war started...at least officially w/Pearl Harbor (Dec 41). 

Hurricane was a great fighter...one of my favorites. As was the Spit...as was the Mustang...as was the...well I love them all HAHAHAHA. 

Their is a romance to the darkest hours however...and for me that means the P-40, F4F, Spitfire, Hurricane. Those planes will always hold a special place in my mind. 

Those were brave Men

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## Thumpalumpacus (Jan 5, 2022)

Yeah, it did get a Merlin in a couple of models.



PAT303 said:


> The P 40 doesn't get the attention it deserves, like the Wildcat its overshadowed by the P 51 and Hellcat.



As a boy, I read and absorbed the idea that the P-40 was quite craptastic, but in the many intervening years I seem to get that like many overlooked airplanes, in the hands of a decent pilot using good tactics it was a dangerous opponent. Relatively maneuverable, good dive characteristics, limited in altitude performance in most cases, but well-armed and rugged.

Maybe not the prom queen, but a good date to dance with if that's what you've got.

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## SaparotRob (Jan 5, 2022)

I'd trade my wife for a P-40 any day. I'll even throw in $20.

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## pbehn (Jan 5, 2022)

Glue Sniffer said:


> You're correct...I was speaking from a strictly American prospective in regards to "holding the line". I would do well to remember that war was happening prior to US entry. Our war started...at least officially w/Pearl Harbor (Dec 41).


By Dec 1941 many things were in progress. The P-39 had been tried in Europe and was being sent to Russia. The Hurricane already was in Russia. The P-40 was in service in N Africa. The first Mustang Mk Is had just arrived in UK. The B-17 had performed its first raids in Europe. Perhaps most important Lease Lend was in place to allow for all this to happen.

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## tomo pauk (Jan 5, 2022)

varsity07840 said:


> The P-40 was a very heavy aircraft with an obsolete airframe.



Care to elaborate?



varsity07840 said:


> The 2 stage 2 speed Merlin would have bettered its altitude performance but increased the weight at the same time thus mitigating the performance increase. Climb rate probably would not have been significantly improved.



Do we know any aircraft where a jump from a 1-stage V12 to a 2-stage V12 failed to bring a major improvement both in RoC and speed?



varsity07840 said:


> Development funds be better spent on the P-38K.



Is there a problem that P-38K solves, for Allies in general, and for P-38s in particular?

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## tomo pauk (Jan 5, 2022)

spicmart said:


> As I understood the main reasons it could not compete with the P-51 were inferior range and worse aerodynamics when using the same engines.
> Wasn't it possible to install large enough tanks to make it a long range escort fighter?



I'd try with extra fuel tanks in front of the ammo boxes on the P-40.



spicmart said:


> I wonder how it would have performed when a Rolls Royce Griffon engine had been installed to make the P-40 a point-defense interceptor in the vein of the Spitfire Mk 14.
> The aerodynamics were not worse than the Spitfire's and the weight was not much higher.
> Guess it could compete with the Spit 14 and the Dora-9



With Griffon - excellent IMO. We'd probably see the comparable turn of speed as with the Spitfire with same engines, unless the radiator set-up is botched.
FWIW, the XP-40Q2 (the last of the P-40 versions, with the 2-stage supercharged V-1710 + water injection and the bubble top) was faster than Fw 190A, about as fast as Fw 190D-9, and about 20-25 mph slower than Spitfire 14 or P-51D (all for ~20000 ft altitude).

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## Shortround6 (Jan 5, 2022)

The P-40 was actually good for about 2 years, 3 is stretching it. And it was fortunate that some of the Early P-40s did not have to be used in combat as built in 1940. 

A Late 1940 P-40 was coming off the line with Spitfire IIs and Hurricane IIs. (Merlin XIIs and Merlin XXs). This is why the Tomahawks went to NA. The RAF didn't want them in England.

Of the Tomahawks that stayed in England one has to compare to what the RAF was flying in 1941. The Squadrons that were flying them were NOT flying Spitfires or Hurricanes in the summer of 1941. The majority of Army cooperation squadrons flying Tomahawks were trading in Lysanders. Most anything was going to look to those pilots. 

The P-40D/E was a very useful improvement. But its was a lot heavier without much improvement in power and Spitfire Vs were showing up months ahead of the P-40D/E. A Spitfire V was well over 1000lbs lighter than a P-40D/E. Normal gross was about 7787bs with 120 US gallons for a British P-40D. The P-40E with 6 guns (and other changes) grossed 7950lbs (still with 120 US gallons of fuel).

The P-40K showed up in May of 1942 (at the factory) and got the 1325hp engine for take-off but power above 12,000ft or so wasn't any better than the older versions (the P-40F did slot in here in Jan 1942 but production was very slow to get going.) Please note that In August of 1942 the RAF was using 4 squadrons of Mustang 1s, 2 squadrons of Spitfire MK IVs with two stage Merlins and 3 squadrons of Typhoons. 


The P-40 did provide good service but it was always a plane that was going be used until something else was available. (the Army had ordered hundreds of P-47s before the 500th P-40 made it out the factory door).

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## gordonm1 (Jan 5, 2022)

denny said:


> What was lacking in the P-40 that made the Allies decide not to upgrade it with a Merlin Engine.?
> Or maybe it was done and the P-40 proved wanting in some area(s).?
> Thank You



Greg's Airplanes and Automobiles on Youtube has a recent video on the P40.
I don't know how to make the movie work here but a link is below.



General things I've read here involve how it's use started before Dec 1941 when the USA was not putting a lot of money into research. The British used it in North Africa in 1941 and they were trying to use it with dogfighting tactics that it was not totally successful at. Then it was Lend Leased to Russia and their airforce had been hit hard by Germany so pilot skill and tactics could have suffered there also.

Greg's video linked above impressed me with how all the added boost and power only increased top speed 20-25mph. That was in part because it still ran out of power before it was able to benefit from reduced drag up high due to the single stage supercharger situation.

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## wuzak (Jan 5, 2022)

gordonm1 said:


> Greg's video linked above impressed me with how all the added boost and power only increased top speed 20-25mph. That was in part because it still ran out of power before it was able to benefit from reduced drag up high due to the single stage supercharger situation.



Using higher boost reduces the critical altitude.

The big power numbers mentioned were very low altitude.


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## Shortround6 (Jan 5, 2022)

tomo pauk said:


> I'd try with extra fuel tanks in front of the ammo boxes on the P-40.
> 
> 
> 
> ...


There seems to be some sort of disconnect with some of the P-40 numbers. 
A lot of P-40 numbers are at reduced loads. 
Like not even using the full internal fuel you can put in the existing tank tanks. In fact many of the P-40Ls and a the first 200-400 P-40Ns (the fast one) didn't even have the forward wing tank installed. 

For instance test of the P-40N (actually a P-40K modified to duplicate the P-40 as much as possible) was run at 7413lbs. One book claims that the P-40N-1 had an empty weight of 6000lbs with a useful load of 1740lb and normal gross weight of 7740lbs. The test plane was 300lbs light.'
This was with four guns and 235rpg and all the weight saving tricks, like taking the electric starter (and a much smaller battery) out. By the time you get to the P-40N-5 the normal weight has gone back to 8300lbs and that is clean, no drop tank or bomb. 

BTW the P-40F has a gross weight of 8505lbs with 235rpg and with only 119US gallons on board. With more ammo, extra oil and the front wing tank full of fuel the gross weight goes to 8860lbs. 

I don't know what you have to take out of a P-40 but the plane is overweight. 

I would note that the Pilots manual for the P-40F and L have a misprint in the specific engine flight chart. While the war emergency section of the chart shows 61in of manifold pressure compared to 48.2in in military power the power/listed seem to be the same power as the take-off power. One wonders how fast the P-40F & L would have been 1435hp at 12,000ft or so.


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## denny (Jan 5, 2022)

gordonm1 said:


> Greg's Airplanes and Automobiles on Youtube has a recent video on the P40.
> I don't know how to make the movie work here but a link is below.
> 
> 
> ...



That was a GREAT Video.
Thank You
There was a question on the comments similar to mine here.
This was Greg's Response







[h3][/h3]  
Greg's Airplanes and Automobiles
3 weeks ago 

The P-51 was superior at high altitude in part due to the newer wing design's higher mach limit.


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## GrauGeist (Jan 6, 2022)

The P-40 had it's genesis pre-war.
At the rate that aircraft design and technology was advancing during the war, the P-40 was not going to be able to keep up.

The only viable alternative was the XP-60C, and even that was eclipsed by the P-47.


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## tomo pauk (Jan 6, 2022)

Shortround6 said:


> I don't know what you have to take out of a P-40 but the plane is overweight.



Thank you for running the numbers.
The overweight part I can agree. A way around being heavy was to install a superior engine that also excels at high altitude, so the performance figures are not just restored to the 'old' values, but improved by a great deal. That never happened to the P-40.
That it was an obsolete airframe (comment from the same sentence that I've quoted above) is dubious IMO.



Shortround6 said:


> I would note that the Pilots manual for the P-40F and L have a misprint in the specific engine flight chart. While the war emergency section of the chart shows 61in of manifold pressure compared to 48.2in in military power the power/listed seem to be the same power as the take-off power. One wonders how fast the P-40F & L would have been 1435hp at 12,000ft or so.



Boost of 61 in Hg = +15 psi. We can see here the Merlin 20 series making 1400 HP at +14 psi at 12000 ft, and almost 1500 HP at ~6000 ft. So I'm not sure what to make from the WER figures from the engine table from P-40F manual, apart that these figures are wrong.



denny said:


> The P-51 was superior at high altitude in part due to the newer wing design's higher mach limit.



P-51 was superior vs. P-40 at all altitudes due to indeed being a newer design with a much lower drag. Superiority at high altitude was a result of having the 2-stage supercharged V-1650-3 or -7 in the nose atop of all that.

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## tomo pauk (Jan 6, 2022)

gordonm1 said:


> Greg's video linked above impressed me with how all the added boost and power only increased top speed 20-25mph. That was in part because it still ran out of power before it was able to benefit from reduced drag up high due to the single stage supercharger situation.


I'd wager to say that an increase in top speed of 20-25 mph is a very good increase. Eg. that was the difference in speed between the Fw 190 and Spitfire V, or Hellcat vs. Zero.

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## pbehn (Jan 6, 2022)

tomo pauk said:


> I'd wager to say that an increase i top speed of 20-25 mph is a very good increase. Eg. that was the difference in speed between the Fw 190 and Spitfire V, or Hellcat vs. Zero.


Not exactly the same point but similar, a difference of 25-30MPH gave superiority in almost all cases, even a top ace cant make up the difference.


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## spicmart (Jan 6, 2022)

tomo pauk said:


> I'd try with extra fuel tanks in front of the ammo boxes on the P-40.
> 
> 
> 
> ...


Please excuse but what do you mean with "turn of speed" and "the radiator set-up is botched"?
Afaik the max speed of the D-9 was the best of the fighters mentioned at about 20.000 ft.


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## tomo pauk (Jan 6, 2022)

spicmart said:


> Please excuse but what do you mean with "turn of speed" and "the radiator set-up is botched"?


"Turn of speed" - a fancy way to say "speed".
Something "is botched" = something is messed up, or something is badly made. A botched radiator set up can add a lot of drag.



spicmart said:


> Afaik the max speed of the D-9 was the best of the fighters mentionede at about 20.000 ft.



At 20000 ft, the D-9 seem to do do ~415 mph in flight tests, and ~430 mph per FW calculations. XP-40Q-2, per test, was making 418 mph there. The Spit 14 did 425 mph at 20000 ft, granted above 20000 ft it was much faster.


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## pbehn (Jan 6, 2022)

tomo pauk said:


> "Turn of speed" - a fancy way to say "speed".


In English idiom a turn of speed is short lived and above normal. Like an athlete who has a "kick" to the finish line, or a football (soccer) player who can change pace in one or two strides but may not be actually a fast runner. In aviation terms it would be the speed at maximum power above max continuous, or could be applied to something like a P-47 with rapid dive acceleration.

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## spicmart (Jan 6, 2022)

tomo pauk said:


> "Turn of speed" - a fancy way to say "speed".
> Something "is botched" = something is messed up, or something is badly made. A botched radiator set up can add a lot of drag.
> 
> 
> ...


Have to find the chart again but I'm sure that at 5500 m the max speed of the D-9 was 703 kmh/438mph, the same max speed of the P-51D at higher altitude.
Can you tell where the Focke Wulf test results compared to calculations were mentioned?


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## tomo pauk (Jan 6, 2022)

spicmart said:


> Can you tell where the Focke Wulf test results compared to calculations were mentioned?



Here.

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## 33k in the air (Jan 6, 2022)

spicmart said:


> As I understood the main reasons it could not compete with the P-51 were inferior range and worse aerodynamics when using the same engines.
> Wasn't it possible to install large enough tanks to make it a long range escort fighter?



For what it's worth, according to the Pilot's Flight Operating Instructions for the P-40N, at 8,400 to 6,600 lbs weight, with no external ordnance, and set for maximum range, at 25,000 feet it could get 5.953 air miles per gallon (256 TAS / 43 GPH). The P-51D, at 9,600 to 8,000 lbs weight, with only wing bomb racks fitted, and set for maximum range, at 25,000 feet it could get 5.865 air miles per gallon (305 TAS / 52 GPH).

It would seem the aerodynamics of the P-40 were not that bad.


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## Shortround6 (Jan 6, 2022)

For the people that want to use the P-40 with a different engine the XP-40Q does offer some food for thought. 

1, The XP-40Q was tested at 9000lbs with 160 US gallons. The weight of 4 .50cal guns and 235rpg was simulated by ballast (they may have had mock ups/gun fairings in the wings) 
2. The XP-40Q used about 1700hp at 20,500ft to reach 422mph. This required over speeding the engine to 3200rpm. 
3. A P-51B needed about 1400hp at 22,000ft to reach 417mph. It could go faster high up, The XP-40Q could not. They had no inter cooler and were using water injection for charge cooling and power was fading slightly at 22,000ft. 

The Allison engine was supposed to weigh about 1515lbs but trying to figure out how much coolant and oil was needed for various engines does get tricky. Trying to squeeze in a 2 stage Griffon was probably out of the question. The single stage Griffon was not going to make the power needed at over 20,000ft.

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## wuzak (Jan 6, 2022)

Shortround6 said:


> 2. The XP-40Q used about 1700hp at 20,500ft to reach 422mph. This required over speeding the engine to 3200rpm.



Wasn't 3,200 rpm the normal maximum rpm for late model V-1710s with 12 counterweight crankshaft? I.e., not overspeeding?

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## tomo pauk (Jan 7, 2022)

Shortround6 said:


> 2. The XP-40Q used about 1700hp at 20,500ft to reach 422mph. This required over speeding the engine to 3200rpm.
> 3. A P-51B needed about 1400hp at 22,000ft to reach 417mph. It could go faster high up, The XP-40Q could not. They had no inter cooler and were using water injection for charge cooling and power was fading slightly at 22,000ft.



The XP-40Q used about 1600 HP at 22000 ft to do 417 mph. Fw 190D-9 used ~1500 PS at 22000 ft for 405-410 mph.
Granted, there was no easy way to beat the P-51 in the "speed vs. HP used @ high altitude" metrics. 



Shortround6 said:


> The Allison engine was supposed to weigh about 1515lbs but trying to figure out how much coolant and oil was needed for various engines does get tricky. Trying to squeeze in a 2 stage Griffon was probably out of the question. The single stage Griffon was not going to make the power needed at over 20,000ft.



P-63's cooling system weighted 356-359 lbs. Lubrication system was 135-137 lbs. P-51B cooling system was 663 lbs (including the intercooling circuit?), lubricating system was at 101 lbs.
Supermarine squeezed the 2-stage Griffon on the Spitfire, FW hooked the long and heavy Jumo 213 and DB 603 engines on the small Fw 190 and Ta 152 fighters. IMO, the only problem with a 2-stage Griffon + P-40 was that there was no steady flow of these engines for wide use.
1-stage Griffon will meant a 400 mph P-40.

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## spicmart (Jan 7, 2022)

tomo pauk said:


> Here.


So the D-9 was quite a bit deficient in performance and not equal to the Spitfire Mk XIV and P-51 at all as often propageted?


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## Shortround6 (Jan 7, 2022)

The single stage Griffon went around 1790lbs
A two stage Griffon went over 2000lbs. Two stage needs a bigger intercooler than the Merlin. 

You can get it in but it is going to need a lot of work. 
The P-40 was a lot heavier than a Spitfire. A Spit MK XIV was about 400lbs lighter than the XP-40Q tested. The Spit had two 20mm and two .50 instead of four .50 cal (or ballast).

A MK XII was about the same weight as a MK IX. They were both lighter than a P-40N-1 (without electric starter and normal battery and without 3rd fuel tank) by about 300lbs. 

Yes you could make a better P-40, but it was going to take a lot of work and it would NOT be better than a P-51 and any improvement to the Spitfire is debatable. 
The "improved" P-40s all sacrificed armament (and ammo capacity).


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## wuzak (Jan 7, 2022)

Shortround6 said:


> The single stage Griffon went around 1790lbs
> A two stage Griffon went over 2000lbs. Two stage needs a bigger intercooler than the Merlin.



And radiator.




Shortround6 said:


> The Spit had two 20mm and two .50 instead of four .50 cal (or ballast).



Early Spitfire XIVs had 2 x 20mm and 4 x 0.303". The XIVe got the 2 x 20mm + 2 x 0.50", but I'm not sure how many of each type were built.

The early Spitfire XIV had the universal wing, which could accommodate 4 x 20mm if required. Only a few Mk Vs were so equipped.

The E-wing was modified from the universal C-wing, so, in theory, the XIV could have used 4 x 20mm.




Shortround6 said:


> A MK XII was about the same weight as a MK IX. They were both lighter than a P-40N-1 (without electric starter and normal battery and without 3rd fuel tank) by about 300lbs.



There were so few Griffons available that they only built 100 Spitfire XIIs. Why would they use them to power P-40s when they had already determined that the Spitfire airframe was better for their purposes?

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## tomo pauk (Jan 7, 2022)

spicmart said:


> So the D-9 was quite a bit deficient in performance and not equal to the Spitfire Mk XIV and P-51 at all as often propageted?



Above 20000 ft, the two Allied fighters were far better.
Between SL and 20000 ft, I'd say these were about equal, though the Spit 14 was the best climber between the 3 of them at any altitude. Push to install the 2-stage Jumo 213F on the later Ds was justified (so was the installation of the 213E or the DB 603L on the Ta 152), but it was also too late, the 213F starting to materialize some time in 1945.


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## Admiral Beez (Jan 7, 2022)

tomo pauk said:


> Is there a problem that P-38K solves, for Allies in general, and for P-38s in particular?


Could the supercharger used to make the Allison superlative on the P-38 have been used on the P-40 with similar, albeit single engined effect?


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## pbehn (Jan 7, 2022)

Admiral Beez said:


> Could the supercharger used to make the Allison superlative on the P-38 have been used on the P-40 with similar, albeit single engined effect?


You need a different plane, to build in a set up like the P-47. This was a consideration when RR were thinking about the two stage Merlin, If they went down the supercharger route, it would go in a Wellington without a problem but what about a Spitfire Hurricane or other.

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## Shortround6 (Jan 7, 2022)

Admiral Beez said:


> Could the supercharger used to make the Allison superlative on the P-38 have been used on the P-40 with similar, albeit single engined effect?








The is most of the extra stuff the P-38 supercharger needed. A few things, like oil coolers were common to both engine set ups. 
This is a late model P-38 with the intercooler in the bottom of the Nacelle.
American Turbos just about always had a number of feet between the engine and the turbo, quite possibly to allow the exhaust gases to cool off just bit Some P-38s had pieces of armor plate to shield the cockpit from the exhaust turbine. 

Now see this picture.




two oil coolers under the prop, the big opening is the intercooler. Now note the radiators in the back of the booms. If you are trying to cool engines making at 1425hp at 25,000ft you need a lot more airflow than using 1150hp at 15-16,000ft (P-40N engine) and even it you can use WER at 10,000ft of 14,000 you still can't cool the engine using the standard P-40 radiators . 
It is the extra volume of the air ducts and intercoolers and the larger radiators that would cause such a problem with a turbo P-40. (that or do away with the intercooler and use a crap load of water-alcohol). It may be able to do it but the changes are play havoc with any back of the envelope estimates of speed/performance.

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## Admiral Beez (Jan 7, 2022)

Shortround6 said:


> The is most of the extra stuff the P-38 supercharger needed. A few things, like oil coolers were common to both engine set ups.


Interesting. How much of that plumbing and cooling could they omit with a Merlin or Griffon powered Lightning? The DH Hornet seems very aerodynamically clean in comparison, with P-38 performance to boot.

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## Shortround6 (Jan 7, 2022)

Admiral Beez said:


> Interesting. How much of that plumping and cooling could they omit with a Merlin or Griffon powered Lightning?
> 
> The DH Hornet seems very aerodynamically clean in comparison.
> 
> View attachment 653934


it was clean, but then they stuck the radiators and intercoolers in the wing leading edge. 
It wasn't that the Merlins could do away with all the lumps and bumps. It was that the P-38 was designed several years earlier and it was designed for 1100hp engines. The intercoolers and radiators designed for 1100hp engines weren't big enough for 1425-1600hp engines and they had to just do minimum changes to get the engines to work.

The DH 103 not only used several years worth of radiator design work from the Mosquito it used a special version of the Merlin to make the engine as compact as possible much. Mostly by changing the layout of the accessories.

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## tomo pauk (Jan 8, 2022)

Shortround6 said:


> it was clean, but then they stuck the radiators and intercoolers in the wing leading edge.
> It wasn't that the Merlins could do away with all the lumps and bumps. It was that the P-38 was designed several years earlier and it was designed for 1100hp engines. The intercoolers and radiators designed for 1100hp engines weren't big enough for 1425-1600hp engines and they had to just do minimum changes to get the engines to work.



P-38 have had a number of details that were adding to drag and thus both robbing the speed and/or lowering the critical Mach number. The ram air intake was a draggy detail, Hornet had those designed better - in the wing leading edge outboard of engines (switch from updraft to downdraft carbs made that possible). Cooling air inlets for the turbines also added to the drag, so did the 'dirty' area around the turbines; there is probably no easy way around this?
Canopy was draggy, NACA sugested a more slanted front part of it as well as a more smooth and longer read end of the pod - those changes also improved the critical Mach number. They also suggested elongating the chord of the inboard portion of the wing by either 10 or 20% (makes the thickness-to-chord ratio lower, thus much improving the critical Mach there), in later case the coolant and oil radiators were to go in the extension to both keep CoG undisturbed and to lower the drag even further. 
(another suggestion was to make the inner portion of the wing in a new laminar flow airfoil, but that would've required a wholesale change of that portion of the wing)
Unfortunately, these NACA suggestions never made it in the production P-38s.

After everything is said and done, retrofit of a 2-stage superchaged engine in place of an 1-stage S/Ced engine was a far easier thing to make.

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## Venturi (Jan 9, 2022)

Overweight,
Or overbuilt?
How many Gs in multi-axes was say the Spitfire able to take (or even rated for) compared to the P40?
Increased airframe strength costs,
And that is in weight. 
Additionally range costs weight,
And the P40 had much more than the Spit. 
Compare it to the P51, and it is lighter. 
More advanced Aerodynamics and two stage supercharger are what was lacking. But compared to fighters of similar design age, aerodynamics were fine. Maybe not as superlative aero as the Spitfire.

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## Shortround6 (Jan 9, 2022)

The P-40 got into action (and I mean just flying in squadron service) late after a long, long development. Counting the P-36 here. 

However the P-40 was a large extent, all that was available in 1940/41/42. 
The Allison engine also took too long to get into "world" standards. 
The US Army didn't help with unrealistic expectations for armament. 

From AHT.
Type...........total production by end 1942..............production in 1942 alone
P-38............................1687..........................................................1479
P-39............................2871..........................................................1982
P-40...........................6883...........................................................3854
P-47...........................533...............................................................532
P-51 (*)....................772................................................................634
F4F.............................1900...........................................................1470
F4U............................179................................................................178
F6F..............................10...................................................................10.

F-51 does not include A-36 production.

Allison did a heck of job building the Allison, especially for a engine company that had only built under 100 engines during the 1930. 
But the Allison's of 1940 were NOT up to standards of either Britain or Germany. By the time Curtiss had built the first 100 P-40s the British were building Spitfires IIs with Merlin XIIs and the first Hurricane IIs with Merlin XXs were just leaving the factory. The P-40 would not see a Merlin XX for about one more year and would take another 6-9 months for production P-40s with Merlin engines to show up. Bf 109Gs were showing up in combat before the Merlin powered P-40s showed up. It took Allison about 1 year get the 1150hp rating up to 15-15,000ft over the 11,500hp attitude. This was over 1 1/2 years from even the Merlin 45. 

Had Allison been able to get the 9.60 gears into production in Dec 1941 and had the P-40 been saddled with 300-400 less armament weight (and a bit less structural weight) then it might have been closer to it's adversaries. 

With 1040-1150hp engines the idea that you could stick over 1000lbs of guns and ammo inside the wing the P-40 and not cripple the performance is a source of wonderment. 
Granted it was not often (if ever?) used but how much of the weight increase of the wings (and other things) from the P-40C to P-40D was due to increase in armament weight. 
Which cannot be taken back out as easily as just taking out guns and ammo.

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## drgondog (Jan 9, 2022)

I would argue the point "P-51D was not a good climber when compared to Fw 190 and Bf 109". It was, at 67" vs 1.42 ata for Bf 109G-6 and 1.42 ata vs Fw 190A-7 and A-8 at Combat Weight GW at T.O. Only (USAAF) the P-47M and P-38J with FULLY functional engines outclimbed the P-51B/D through 25K, After 25K the P-51B/D caught up and passed. With 75" the P-51B/D easily outclimbed the 109 as medium altitudes were reached with 1650-7 engine and continued to increase at higher altitudes. The Spit IX and XIV easily outclimbed every Mustang save XP-51F/G and P-51H.

In "Bastard Stepchild" II presented the comparative data and graphics at full combat gross weight (internal) and included wing racks for the P-51B/D. I had Kurfurst (Dr. Millei Adam) check my data to make sure I wasn't understating the 109 and 190 values. BTW the P-51D with new cleaner bomb racks at Same GW as P-51B outclimbed and out ran the P-51B at any Boost. Note - when I say 'Same' I mean both at 9600 pounds with 1650-7, 67", 3000 RPM. That P-51D TO was 500 pounds less than full internal loading of fuel, oil and ammo.

To the question of P-40 combined with 1650-3 or -7, it would certainly enabled better performance in both climb and straight away speed, climb comparable or better to P-51B/D due to lower W/L but the P-40 Parasite Drag was more than 30% greater than P-51B/D which would kill much of the speed potential to be gained with the heavier more powerful engine.

That said, Packard could not come close to production quantities committed for RAF/RCAF and the Mustang - which also impacted the projected spares commitment in 1944. Echols in a huge brainfart (malice?) approved a thousand 1650-1 spares (in Summer 1943) for Q1 1944, and if read between the lines - got his ass kicked because P-51B- airframes were complete save engines into August 1943. The ONLY hope for Curtiss to upgrade performance on P-40 airframe was the two stage Allison installed on the P-40Q.

The P-40 maxed out internal fuel at 161 gallons, with growth limitations in aft fuse 62 gal tank (CG), and further increases in wing storage due to landing gear and gun arrangements. That would have yielded perhaps 170 mi combat radius with external drop tanks under ETO escort planning guidelines 

EDIT - The Brain Fairy was shacked up when I was calculating this - I can ony point to botched pacemeker op that I redo next week.

As Tomo pointed out, internal 161 gal with an external Combat tank would have been less than a P-51B (with 180 gal internal plus twox75s) but better than P-47 w/75 gal tank - at significanly lower altitude

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## tomo pauk (Jan 9, 2022)

drgondog said:


> The ONLY hope for Curtiss to upgrade performance on P-40 airframe was the two stage Allison installed on the P-40Q.



Yes, going with a 2-stage engine from Allison is the only plausible way.



drgondog said:


> The P-40 maxed out internal fuel at 161 gallons, with growth limitations in aft fuse 62 gal tank (CG), and further increases in wing storage due to landing gear and gun arrangements. That would have yielded perhaps 170 mi combat radius with external drop tanks under ETO escort planning guidelines



I'm sure that a P-40 cannot fulfil the ETO escort planing guidelines, the engine as-is does not give enough of power for cruising at 310+- mph TAS at 25000 ft. The 2-stage V-1710 should be capable for that. I'd try and nick the drop tank from the P-38, but that's just me.
Bill - we'd probably get a lot more than 170 miles with 160 + 150 gals of fuel? P-51B was good for 460 mile radius with 180 + 150 gals under the 'ETO rules'.

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## drgondog (Jan 9, 2022)

Venturi said:


> Overweight,
> Or overbuilt?
> How many Gs in multi-axes was say the Spitfire able to take (or even rated for) compared to the P40?


All about GW compared to Design weight. ALL fighters grew in GW as missions dictated changes and new equipment. IIRC the Spit (original) was designed to 7G Limit and 10.5 G Ultimate to its original design GW. Comparably the P-40 original Empty Weight was 5367/Combat GW = 6807 designed to 8G Limit and 12G Ultimate. As Combat Weight of the P-40F was 7069 pounds, reducing Limit load to 7.7 G.


Venturi said:


> Increased airframe strength costs,
> And that is in weight.
> Additionally range costs weight,
> And the P40 had much more than the Spit.
> ...


What you must do to compare is to a.) Understand Brit vs US structure limits standards, b.) the original Gross Weight of the aircraft for which the Design Limit Load existed, and c.) The growth of the GW overtime and how that reduced allowable Limit Loads.

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## drgondog (Jan 9, 2022)

tomo pauk said:


> Yes, going with a 2-stage engine from Allison is the only plausible way.
> 
> 
> 
> ...


Tomo - yes. Brainfart. It would have been comparable to P-38 with 300gal internal fuel and external 300 gals.


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## pbehn (Jan 9, 2022)

Venturi said:


> Overweight,
> Or overbuilt?
> How many Gs in multi-axes was say the Spitfire able to take (or even rated for) compared to the P40?
> Increased airframe strength costs,
> ...


The Spitfire was around 2 years before the P-40 in development (based on first flights of prototype and production machines), I dont think there was any issue with what it could do as regards "G" forces in multi axes in flight was there? There were issues on landing loads. The late war Griffon versions were very heavy machines, but the wings were substantially modified, though they looked pretty similar.


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## BiffF15 (Jan 9, 2022)

drgondog said:


> I would argue the point "P-51D was not a good climber when compared to Fw 190 and Bf 109". It was, at 67" vs 1.42 ata for Bf 109G-6 and 1.42 ata vs Fw 190A-7 and A-8 at Combat Weight GW at T.O. Only (USAAF) the P-47M and P-38J with FULLY functional engines outclimbed the P-51B/D through 25K, After 25K the P-51B/D caught up and passed. With 75" the P-51B/D easily outclimbed the 109 as medium altitudes were reached with 1650-7 engine and continued to increase at higher altitudes. The Spit IX and XIV easily outclimbed every Mustang save XP-51F/G and P-51H.
> 
> In "Bastard Stepchild" II presented the comparative data and graphics at full combat gross weight (internal) and included wing racks for the P-51B/D. I had Kurfurst (Dr. Millei Adam) check my data to make sure I wasn't understating the 109 and 190 values. BTW the P-51D with new cleaner bomb racks at Same GW as P-51B outclimbed and out ran the P-51B at any Boost. Note - when I say 'Same' I mean both at 9600 pounds with 1650-7, 67", 3000 RPM. That P-51D TO was 500 pounds less than full internal loading of fuel, oil and ammo.
> 
> ...


Bill,

I understand the comparison of Combat GW between the planes, but how did the climbs compare when they met in battle? How about a Mustang with approx half gas, compared to the 109 / 190 both at half fuel load (weight)? I would think less 1/2 gas in a P-51 would result in a greater percentage of weight gone, and a much better climb rate.

Cheers,
Biff


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## Shortround6 (Jan 9, 2022)

pbehn said:


> The Spitfire was around 2 years before the P-40 in development (based on first flights of prototype and production machines), I dont think there was any issue with what it could do as regards "G" forces in multi axes in flight was there? There were issues on landing loads. The late war Griffon versions were very heavy machines, but the wings were substantially modified, though they looked pretty similar.


Yes, No, Maybe. Perhaps? 

The Curtiss 75 first flew April 1935.





The wing, landing gear, rear fuselage, tail surfaces were pretty close to what they would up with 1939/40.

After a crap load of engine changes (and those turbo charged YP-37s)




they wound up with the 10th P-36 off the production line finished off as the XP-40.




Work started in March of 1938, first flight was Oct 14th 1938. 
The Prototype won the Army Pursuit competition in Jan 1939. 
The big order was placed April 27th 1939 but the first production P-40 was not completed until May 1940. 

This is what I meant by the "long, long" development. 
The first few hundred P-40s were not ready for combat use. 
Initial specifications called for Gross weight of 6807lbs but that was for two .50 cal guns with 200rpg, two .30s guns with 500rpg and 120 gallons of fuel (the tanks would hold 181 gallons at max gross). Curtiss built 778 P-40s in 1940, 582 of them just in the last 4 months. 

The fuselage, tail surfaces, wings and landing gear were very close to the plane of 1935, although beefing up had been done. The Hawk 75/P-40 airframe does standup remarkably well against most of it's contemporaries. But it was no longer in the first tier in 1943.

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## SaparotRob (Jan 9, 2022)

What was the rationale behind mixed caliber armament? Why not all .50's instead of a .30/.50 mix?


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## GrauGeist (Jan 10, 2022)

SaparotRob said:


> What was the rationale behind mixed caliber armament? Why not all .50's instead of a .30/.50 mix?


During the interwar years and even into the early years of WWII, rifle caliber MGs (.30/7mm) were the mainstay of virtually every Air Force (and Naval Air Arm) on earth.
The USAAC used a .50 MG in the mix to provide a bit more hitting power. Around 1940-ish, the U.S. military determined that the hitting power of two .50 MGs was a preferable trade-off to the (then) slower rate-of-fire. The SBD was one of the first US aircraft to be designed with two fixed forward .50 MGs, though the rear gunner position still used a flexible .30 (or two).

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## SaparotRob (Jan 10, 2022)

If a company is designing in .50's from the get go (P-40, right?), why not ditch .30's completely and simplify logistics?


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## GrauGeist (Jan 10, 2022)

SaparotRob said:


> If a company is designing in .50's from the get go (P-40, right?), why not ditch .30's completely and simplify logistics?


It's not the company's decision.

They're building to Government specs.

Like I mentioned a bit ago, virtually every military on earth was using rifle-caliber machine guns in their aircraft designs before WWII.

U.S.: 30-06
Britain: .303
Italy: 7.7mm
Japan: 7.7mm
France: 7.5mm
Germany: 7.92mm
Netherlands: 7.9mm
Soviet Union: 7.62mm
Poland: 7.92mm
Romania: 7.92mm
Bulgaria: 7.92mm
Czechoslovakia: 7.92mm

The list goes on, but you get the idea...

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## Shortround6 (Jan 10, 2022)

The .50 cal gun weighed 3 times as the .30 cal gun and the ammo weighed 5 times as much per round. 

In 1939 and into 1940 the US .50 gun had a rate of fire of 600rpm at best, the .30 cal gun had rate of fire of 1200rpm. They were able to increase the rate of fire of the .50 cal at some point in 1940 to about 800rpm. 
They were able to retrofit existing guns with parts kits.

The supply of .50 cal guns was not enough to provide all the guns that the US wanted. It took time to provide the extra factories.

And lastly, the US was also in the middle of changing the .50 cal cartridge. New propellants allowed for increased velocity. This was also messing up logistics. Which guns would get the new ammo and which guns (Navy AA?) would get the old ammo.

That was in a perfect world. 
The .50 guns gave quite a bit of trouble in 1940 and 1941 and beyond. In some cases the .30 cal guns worked and the .50 cal guns did not. The British Tomahawks took quite a while to get the .50 guns fire with any degree of reliability.

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## drgondog (Jan 10, 2022)

Shortround6 said:


> The .50 cal gun weighed 3 times as the .30 cal gun and the ammo weighed 5 times as much per round.
> 
> In 1939 and into 1940 the US .50 gun had a rate of fire of 600rpm at best, the .30 cal gun had rate of fire of 1200rpm. They were able to increase the rate of fire of the .50 cal at some point in 1940 to about 800rpm.
> They were able to retrofit existing guns with parts kits.
> ...


All good SR - but think you meant 30 cal = 5 per pound and 50 cal = 3 per pound

Additional to one of the posters re: Logistics. The AAC/AAF was still part of US Army and in 1940 there were a hell of a lot more 30 cal/30-06 rounds in US Army stores and field than 50 caliber rounds (or M2).

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## drgondog (Jan 10, 2022)

BiffF15 said:


> Bill,
> 
> I understand the comparison of Combat GW between the planes, but how did the climbs compare when they met in battle? How about a Mustang with approx half gas, compared to the 109 / 190 both at half fuel load (weight)? I would think less 1/2 gas in a P-51 would result in a greater percentage of weight gone, and a much better climb rate.
> 
> ...


Of course you are correct. The fuel fraction of a P-51B/D with 85 gal internal fuel is much more than Bf 109 and Fw 190A, so comparing at 50% fuel fraction as combat GW is advantage P-51B. That said, that is kinda where the P-51B was when engaging in combat over Munich, Berlin, Posnan.

The ROC for the P-51B at full combat weight (with 269 gal) was ~ 3600fpm at 67" 3000 rpm at SL (about same as Bf 109G-6 with DB605AS with 503 rack for drop tank) but for 8600#GW at 75" and 3000 rpm ~ 4500fpm at SL and 3600 at 18,000 feet. 

When the P-51B was approved for 67", the full transition to 85 gal tank had not occurred and the 75 gal tanks were dropped before reaching Brunswick. Given draw down for warm up, take off, assembly and initial climb, the 51B at target was probably around 130-140 gallons or about 8400 pounds (vs 9600 at full GW take off w/269 gal). A WL of 36psf compared to 41 at T.O. is a huge difference - more in Spitfire class and significantly below full internal combat load of a Bf 109G6 and Fw 190A-7. Given that 60 gal drop tanks were being used in 1944 on 109G and Fw 190A, they were entering combat with a higher % of their fuel fraction than the P-51B.

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## PAT303 (Jan 10, 2022)

SaparotRob said:


> If a company is designing in .50's from the get go (P-40, right?), why not ditch .30's completely and simplify logistics?


Because the .50's didn't work if fitted in the wings, they would jam as soon as the plane pulled G's, likewise, as SR has posted what .50's and ammunition are you using and where?, 1939-40 see's a change from low velocity slow firing guns to high velocity quicker firing guns.

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## drgondog (Jan 10, 2022)

PAT303 said:


> Because the .50's didn't work if fitted in the wings, they would jam as soon as the plane pulled G's, likewise, as SR has posted what .50's and ammunition are you using and where?, 1939-40 see's a change from low velocity slow firing guns to high velocity quicker firing guns.


First comment I have heard that P-40 had jamming problems during maneuvers? They were mounted upright whereas the A-36/P-51A/P-51B had canted mounts.

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## Shortround6 (Jan 10, 2022)

drgondog said:


> All good SR - but think you meant 30 cal = 5 per pound and 50 cal = 3 per pound
> 
> Additional to one of the posters re: Logistics. The AAC/AAF was still part of US Army and in 1940 there were a hell of a lot more 30 cal/30-06 rounds in US Army stores and field than 50 caliber rounds (or M2).



I may not have stated it clearly. but, 
.30 cal was about 6lbs/100 rounds
.50 cal was about 30lbs/100 rounds

Or the .50 cal round was about 5 times as heavy as a .30 cal round.

As you state there were millions more rounds of .30 cal ammo than .50. But when they are trying to build airplanes with 1000-1100hp engines trying to stick in the wing four to six .50 cal guns can run up the payload real quick. 
By the end of 1940 Curtiss was building over 200 airplanes per month. Trying to build planes at that rate while incorporating the "flavor of the month" armament has it's own problems. 
The P-40D did try with making provisions to mount a 20mm cannon underwing in addition to or in place of one the .50 ca guns. It is in the manual for the plane but I don't think any planes actually went operational with the 20mm guns.

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## GrauGeist (Jan 10, 2022)

drgondog said:


> First comment I have heard that P-40 had jamming problems during maneuvers? They were mounted upright whereas the A-36/P-51A/P-51B had canted mounts.


I don't recall hearing that either and in a bit of irony, it was the .30 MG that jammed on Lt. Rasmussen's P-36, leaving him with only a .50 MG to engage the Japanese that morning at Pearl Harbor.

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## Venturi (Jan 10, 2022)

In Europe, the movement was towards cannon for bomber work, in combination with fast firing mg for fighter work. All about rate of fire (anti fighters, high deflection shots), vs individual shell hitting power (anti bombers, low deflection shots) for the cannon. For example the ROF for oerlikon (sp?) cannon was quite low (Japanese zero also had a variant of this weapon, of course it was also mounted on Bf109E).
The US viewed the 50cal as almost a cannon shell, and that is pretty much correct when you look at the bullet weights of a .30-06 and the .50BMG as shortround points out. Pre war, not too many 20mm cannon were out there.
In this way, the US was following standard principles with “heavy” weapons for bombers and “light” weapons for fighters. Later in 1940 of course the British proved 8 or 12 rifle MGs are sufficient if not optimal for both, combat experience reflected in the P40D and E designs. Of course the US navy along with multistage supercharging had already had gone to 4x 50BMG with the Wildcat.


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## GrauGeist (Jan 10, 2022)

Though in the 1930's, the USAAC was looking at cannon for their bomber interceptors (designs like the YFM-1, P-38 and P-39 reflect this) and the Army did try and adapt cannon to just about everything at one point or another.


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## Schweik (Jan 10, 2022)

Shortround6 said:


> This covers a lot of area/time.
> 
> Actually the P-40Ls were produced from Jan 1943 to April of 1943.
> Allison was not producing enough more powerful engines. The 1943 engines had about 4,000ft more altitude than the 1942 engines. Change over was actually at the end of Nov 1942 with the P-40M model. But 15,000-15,500 altitude for an 1150hp engine wasn't good enough for a general purpose fighter in 1943. It was good enough to fill in and it was good for low altitude work.
> ...



*P-40 Myths *
Most people confuse single-speed supercharger with no supercharger. I know you do not suffer from this misconception I just mention it because it is one of the typical sticking points.
The other myth is that it was slow and unmaneuverable but rugged (it was faster than almost every Japanese fighter it faced, and could out turn all of the German and Italian monoplane fighters). It's real flaws were that it climbed poorly and had a low effective ceiling. I.e. it didn't perform at anywhere near high altitudes.

In spite of this, P-40s were well liked by most (not all) of their pilots because once they learned it's strengths and weaknesses, it had a pretty high pilot survival rate. This was partly because it was indeed rugged, but ruggedness in a military aircraft is far less conducive to pilot survival than maneuverability. In the case of the P-40 this meant a good roll and turn, high dive speed and dive acceleration, and ability to continue to turn and roll at high speeds. The latter meant it was often able to disengage from combat when it wasn't going well, both in the Pacific and in the Med and Russia.





Australian Ace Clive Caldwell before his heavily damaged Tomahawk, just after a close call with a German _Experten_

*



*
An American pilot with the 79th FG in Italy examines a 20mm shell hole in his P-40L. He had 5 cannon strikes on this aircraft, and in the video this image is from he found the plug from one of the shells stuck in his wing. He wore that plug as a pendant for the rest of the war.

*Early P-40s in US use were restricted to lower altitudes than most people realize*
Allison-engined P-40s ranged widely in terms of their functional combat ceiling, which was a bit above the critical altitude for the engine. It varied mainly based on the supercharger gears. The typical altitude mentioned is 15,000 or 16,000 ft, but that was for the early Tomahawk variants, which (aside from Pearl Harbor) were really only used by the British and the Soviets. The P-40E, the one almost always featured in synopsis, movies, video games, and models, actually had a lower 'performance altitude' of about 12,000 ft. It was also slower than typically reported, at least at the original power settings, topping out a bit over 340 mph. They could be used at higher altitudes, as they did successfully during the defense of Darwin up to 25,000 ft, but the aircraft is so starved for power at that height they are really taking a big risk, and that was only done out of desperation.

Later the up-engined P-40Es and K (which is just an improved E) got the Allison 1710-73 engine, which (which using higher octane fuel) made them faster especially down low (and conferring the oft quoted top speed of ~360 mph at their highest altitude), and yet the performance altitude was still about 12,000 ft. At 16,000 these planes were already struggling. This meant in the Med they were contending with German fighters that could dive down from 8-12,000 feet above them.

The P-40M and some marks of the N had a different supercharger gear ratio and pushed the critical altitude up to about 16,000 ft, and the performance limit to about maybe 18,000 ft. This was the 'hot' interceptor configuration of the P-40N, which included the first few hundred and some from later marks, which could make ~380 mph, but these were comparatively rare. By the time the N model came out Allison P-40s were only being used as fighters in the Pacific and Burma, and by the Russians. In the MTO the British were using them exclusively as fighter bombers and max speed was about 345 mph.

But because it was still always a single speed supercharger, there was no real fix here, as P-40 marks with the higher gear ratio (and thus higher altitude limits) had much less power at low altitude. Whereas P-40K and later model P-40E could produce up to 1570 hp at WEP down around 2,000 ft or lower (from the manual, not counting overboosting) which made them very effective at escaping pursuit in a diving escape maneuver, (and very dangerous to tangle with down low) - the higher geared Allisons couldn't produce much more than 1,200 hp at any altitude. So many pilots preferred the K. There were more Aces flying the K in China, the Solomons and in Russia than any other P-40 type. Later in the war (1944) the N and M ended up being used in India to cover the 'hump' air corridor into Burma because they could make it over the mountains better.









Restored merlin P-40 "Lee's Hope" at Duxford.

*P-40F with Merlin was a major improvement*
By comparison, the P-40F (available from late 1941) and L was much more versatile, because it had the two speed supercharger. So it had good speed at low-medium altitude speed, around 4 -6,000 ft, and then the higher middle altitude, with a critical altitude about 17,500 ft and good performance up to around 21-22,000 ft. (370 mph at 20,400 ft according to this British test) This was of crucial importance in the MTO, which is why the Merlin-engined version was the only type used by the American fighter squadrons in that Theater (with a few brief exceptions of some K models due to temporary shortages). German and Italian fighters often attacked from as high as 25,000 ft and the high altitude performance of the Merlin Engined P-40s did well.

All five of the US P-40 fighter groups (33rd, 57th, 79th, 324th, and 325th), plus one independent squadron, (99th FS / Tuskeegee) active in the MTO had good to excellent combat records, and this is verified in the daily combat accounts in Mediterranean Air War. For a brief period from mid-1942, the P-40F was in heavy demand, until the middle of 1943, and arguably it was the best Allied fighter in the MTO overall until the Spit IX and later VIII arrived.

As for being a year behind, I don't think the P-40 let alone the F was ever really behind in the Pacific or China (it wasn't necessarily ahead either but when you look at realtively little known units like the 23rd FG in China and 49th FG in the Pacific they did very well). There was a general lag in the MTO where it was used against German and Italian fighters, in the sense that all nations seemed to take a while to send their most modern types down there, and it was as comparable to the Bf 109F and early G models that it faced, as well as the MC 200, 202 and 205, and the Spit V it flew with. The P-38 was probably a little bit better overall but it was having trouble in that Theater. I think the P-40F does deserve a bit more attention than it gets. It's one of those cases where a single type (P-40) has such a wide variance in subtypes in terms of it's effectiveness and combat record, that this model and the equally important K model tend to get overlooked. If it had a different designation it would probably be more famous.

*They made the right decision with the Merlins - P-51 (and Spitfire) were better regardless*
P-51 however was a better candidate for the 2 stage merlins both because of it's cooling configuration and because it was such an aerodynamically efficient / low drag design. Even with the Allison Engine the P-51 was 30-40 mph faster and it had the potential for much greater range. The P-38 and P-47 were also better than a P-40 once they worked out the various issues. The P-40Q was an interesting design which might have had a small role if not for the crash of several prototypes and overall major problems with Curtis Aircraft which put them on the outs with War Dept. officials, but I think the P-51 was still better. The Spitfire VIII and IX were also far and away better fighters than any mark of P-40.

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## Schweik (Jan 10, 2022)

gordonm1 said:


> Greg's Airplanes and Automobiles on Youtube has a recent video on the P40.
> I don't know how to make the movie work here but a link is below.
> 
> 
> ...




I watched that a few weeks ago and liked it (I like most of his videos) but I believe he greatly underestimates the importance of the higher altitude performance of the Merlin engined types, at least against German and Italian fighters. If you look at the war records from the Med, the British still had a lot of Kittyhawk I and Ia squadrons flying as late as mid 1943, and the poor South Africans even had some Tomahawks. The Kittyhawk Is were getting slaughtered by 109s and MC 202s. The (Merlin Engined) P-40F/Ls and Kittyhawk IIs however, were more than holding their own.

The top speeds are roughly the same, and 8,000 feet of performance ceiling doesn't sound like that big of a deal, but it absolutely was. By the end of 1942 the P-40E / Kittyhawk Ia was no longer really viable as a fighter. It couldn't handle Bf 109F-4 and was doomed against a G-2 most of the time. But the merlin types were flying escort over Sardinia on their own and doing very well. Even by the time of Anzio, when they were clearly getting obsolete, the F and L models were still not taking the kinds of heavy losses that Hurricanes or Kittyahwk I did over North Africa.

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## Schweik (Jan 10, 2022)

One other point to make - For the MTO, the P-40B/C (Tomahawk) was actually a better fighter than the original P-40D and E (Kittyhawk I and Ia), at least when the latter were flying according to their manual at a max of 46" Hg. The Kittyhawk was much heavier, had problems with many of it's new features like the heavy wing guns, and was definitely underpowered. A Tomahawk IIa had a maximum climb rate of about 3,000 fpm, whereas a Kittyhawk I had a maximum climb rate of less than 2,000 fpm and was slower. It wasn't until they worked out how to increase boost (to 56 or 57 Hg) and RPM (to 3,000 - 3,200), which took a few months, that they were able to compete with their early Kittyhawks against the Bf 109F2s and MC 202s. When the F-4s were coming in they were starting to get into trouble again.

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## tomo pauk (Jan 10, 2022)

Schweik said:


> *P-40 Myths *
> Most people confuse single-speed supercharger with no supercharger. I know you do not suffer from this misconception I just mention it because it is one of the typical sticking points.
> The other myth is that it was slow and unmaneuverable but rugged (it was faster than almost every Japanese fighter it faced, and could out turn all of the German and Italian monoplane fighters). It's real flaws were that it climbed poorly and had a low effective ceiling. I.e. it didn't perform at anywhere near high altitudes.



That P-40 was slow was no myth. 90% of Japanese fighters in service were also slow.
Most of today's people, when they see no turbo attached to an engine on a ww2 A/C, reckon that there was no supercharger whatsoever. That a S/C migth be driven by engine itself is probably seen as an attempt to point out to a _perpetuum mobile_.



Schweik said:


> The P-40E, the one almost always featured in synopsis, movies, video games, and models, actually had a lower 'performance altitude' of about 12,000 ft. It was also slower than typically reported, at least at the original power settings, topping out a bit over 340 mph.



Engines on the P-40E and P-40C were making the same power at 15000 ft, ie. 1000-1050 HP there. The -39 (on P-40D and E) was rated for higher boost by the manufacturer, so it's military power was 1150 HP at 12000 ft, vs. the -33 (on P-40, -B and -C) having the mil power of 1040 HP at 14000 ft (a tad lower with backfire screens installed). Take-off power was also greater on the -39: 1150 HP vs. 1040 for the -33.
Unfortunately, the V1710-39 was a lesser engine than it was the Merlin III in 1939. It was comparable to the low-level Merlin 45M - the one with smaller impeller (9.50 in diameter, ie. same as on the V-1710).

P-40B, -C, -D and -E saw incremental weight creep (almost 1100 lbs for the basic weight), rendering the V-1710-39 obsolete the day it was introduced.



Schweik said:


> Later the up-engined P-40Es and K (which is just an improved E) got the Allison 1710-73 engine, which (which using higher octane fuel) made them faster especially down low (and conferring the oft quoted top speed of ~360 mph at their highest altitude), and yet the performance altitude was still about 12,000 ft. At 16,000 these planes were already struggling. This meant in the Med they were contending with German fighters that could dive down from 8-12,000 feet above them.



Unfortunately, the -73 engine still had the same supercharger and it's drive as it was the case with -39, and barely different than the -33. Changes in engine (mostly related to crankshaft and crankcase) allowed for increased boost and thus increase of power with the 100/130 grade fuel.



Schweik said:


> But because it was still always a single speed supercharger, there was no real fix here, as P-40 marks with the higher gear ratio (and thus higher altitude limits) had much less power at low altitude. Whereas P-40K and later model P-40E could produce up to 1570 hp at WEP down around 2,000 ft or lower (from the manual, not counting overboosting) which made them very effective at escaping pursuit in a diving escape maneuver, (and very dangerous to tangle with down low) - the higher geared Allisons couldn't produce much more than 1,200 hp at any altitude.



It was about the S/C being with just one speed drive, but it was also about the S/C being physically small on the V-1710 - not a good thing if the engine is also small. Spinning it up faster, as it was the case on the engines on P-40M and N, gave only so much. That improvement was late by perhaps 12 months, if not 18 months?
Higher-geared V-1710s did a lot more than 1200 HP at any altitude, eg. almost 1500 HP on the P-40N (chart here); less on the late P-39s (not sure about the reasons).



Schweik said:


> By comparison, the P-40F (available from late 1941) and L was much more versatile, because it had the two speed supercharger. So it had good speed at low-medium altitude speed, around 4 -6,000 ft, and then the higher middle altitude, with a critical altitude about 17,500 ft and good performance up to around 21-22,000 ft.



Merlin XX (the V-1650-1 being the member of the family) was outfitted with a bigger S/C (10.25 in impeller diameter) that was also turning fast, at 9.49 times the crankshaft speed. That it was a 2-speed engine had no bearing on high-alt capability, it could've been with just 1 speed S/C drive (the high one) and still beat a V-1710 on a P-40/39/51.
We can see the Merlin 45 - an 1-speed S/C from Merlin XX, also with the much improved inlet, the impeller turning at 9.089 times the crankshaft speed. It gave about the same power above 12000 ft as the Merlin XX.

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## PAT303 (Jan 10, 2022)

drgondog said:


> First comment I have heard that P-40 had jamming problems during maneuvers? They were mounted upright whereas the A-36/P-51A/P-51B had canted mounts.


Didn't matter how they were mounted, the guns were tested with the plane flying straight and level, RAAF .50's didn't work and neither did the same guns fitted to FAA F4 Martlets, we have covered this in other threads.


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## Schweik (Jan 10, 2022)

tomo pauk said:


> That P-40 was slow was no myth. 90% of Japanese fighters in service were also slow.
> Most of today's people, when they see no turbo attached to an engine on a ww2 A/C, reckon that there was no supercharger whatsoever. That a S/C migth be driven by engine itself is probably seen as an attempt to point out to a _perpetuum mobile_.



Right but my real point is that they weren't slow compared to their opposition. I would also say, 360 mph in early 1942 (once they are pushing the engines a bit harder) is not slow, it's about average for a fighter. Some were faster but not necessarily in the field. Another issue with the P-40 (in it's favor) is that unlike the Spit and the 109 it did not seem to suffer that much from it's Tropical Filter.



tomo pauk said:


> Engines on the P-40E and P-40C were making the same power at 15000 ft, ie. 1000-1050 HP there. The -39 (on P-40D and E) was rated for higher boost by the manufacturer, so it's military power was 1150 HP at 12000 ft, vs. the -33 (on P-40, -B and -C) having the mil power of 1040 HP at 14000 ft (a tad lower with backfire screens installed). Take-off power was also greater on the -39: 1150 HP vs. 1040 for the -33.


My understanding is that the -33 had a slightly higher ratio, I'd have to go pull down some books to check. But for example according to this Sept 1941 data sheet, it had a critical altitude at military power of 13,600, where it is producing 1040 hp, and performance is usually still pretty good for another 2,000 feet above that. Which puts you at about 15,600

This similar chart from Dec 1942 for the P-40D/E shows a critical altitude at military power of 11,800 ft. Which puts you at 13,800 (but I think that was pushing it!). It's interesting though that the chart does show 56" Hg WEP setting for 1470 HP at Sea Level. I don't think a lot of units in the field got that memo until a bit later (like March).

P-40D/E was also for sure heavier. Though it was also much better protected (not just with armor but better self sealing tanks, better redundancy for flight controls etc.)



tomo pauk said:


> Unfortunately, the V1710-39 was a lesser engine than it was the Merlin III in 1939. It was comparable to the low-level Merlin 45M - the one with smaller impeller (9.50 in diameter, ie. same as on the V-1710).
> 
> P-40B, -C, -D and -E saw incremental weight creep (almost 1100 lbs for the basic weight), rendering the V-1710-39 obsolete the day it was introduced.


Well yeah, until they improved it


tomo pauk said:


> Unfortunately, the -73 engine still had the same supercharger and it's drive as it was the case with -39, and barely different than the -33. Changes in engine (mostly related to crankshaft and crankcase) allowed for increased boost and thus increase of power with the 100/130 grade fuel.


The -73 seems to basically be identical to the -39 except it was toughened (crank case, crank shaft, and bearings) for higher boost. Many of the -39s were apparently refitted with some of these same parts or the aircraft using them were given -73s which is all a bit confusing, but the net result is you got some souped up P-40Es which were really more like Ks.

The K also got some improvement to gun and/or ammunition storage which resulted in fewer stoppages while shooting.



tomo pauk said:


> It was about the S/C being with just one speed drive, but it was also about the S/C being physically small on the V-1710 - not a good thing if the engine is also small. Spinning it up faster, as it was the case on the engines on P-40M and N, gave only so much. That improvement was late by perhaps 12 months, if not 18 months?
> Higher-geared V-1710s did a lot more than 1200 HP at any altitude, eg. almost 1500 HP on the P-40N (chart here); less on the late P-39s (not sure about the reasons).


My understanding is that there were different types of the later generation Allisons, and the variant they put on the 'Interceptor' configurations of the P-40N was the higher boost type, however the 'Fighter Bomber' type P-40N and the P-40Ms were limited to lower boost, this chart for a P-40M with the V-1710-81 shows 1360 for WEP and 1200 for takeoff. The infamous Allison Memo also mentions this, that the higher geared Allisons were going to have more trouble with high boost (due to heat, from what I gather).



tomo pauk said:


> Merlin XX (the V-1650-1 being the member of the family) was outfitted with a bigger S/C (10.25 in impeller diameter) that was also turning fast, at 9.49 times the crankshaft speed. That it was a 2-speed engine had no bearing on high-alt capability, it could've been with just 1 speed S/C drive (the high one) and still beat a V-1710 on a P-40/39/51.



Right but without the second speed it would then be relatively a dog down low. As it was the P-40K was considered much faster than the P-40F below 4,000 ft.



tomo pauk said:


> We can see the Merlin 45 - an 1-speed S/C from Merlin XX, also with the much improved inlet, the impeller turning at 9.089 ties the crankshaft speed. It gave about the same power above 12000 ft as the Merlin XX.



But all the single speed superchargers had that problem - you pick where you want to go fast. Down low means poor at high altitude, up high means the reverse. It's just a bit less of an issue with a Spitfire because that is a much lighter aircraft (at least pre-Griffon)


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## Schweik (Jan 10, 2022)

PAT303 said:


> Didn't matter how they were mounted, the guns were tested with the plane flying straight and level, RAAF .50's didn't work and neither did the same guns fitted to FAA F4 Martlets, we have covered this in other threads.



They had a lot of problems with the .50s in the first few months (for several reason, both aircraft and ammunition), though this was starting to dramatically improve by mid 1942 (not every unit sorted it out at the same time).

They also had quite severe issues with the Hispano cannons particularly in the Tropical conditions, around the same time.


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## PAT303 (Jan 10, 2022)

Schweik said:


> They had a lot of problems with the .50s in the first few months (for several reason, both aircraft and ammunition), though this was starting to dramatically improve by mid 1942 (not every unit sorted it out at the same time).
> 
> They also had quite severe issues with the Hispano cannons particularly in the Tropical conditions, around the same time.


In 1939-40 the .30's from all nations were a proven gun yet the .50 and 20mm were described by the RAF as underdeveloped, including the ammunition.

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## Schweik (Jan 10, 2022)

PAT303 said:


> In 1939-40 the .30's from all nations were a proven gun yet the .50 and 20mm were described by the RAF as underdeveloped, including the ammunition.



It's kind of the perpetual dilemma of the war (and speaks to the circumstances of aircraft like the P-40 and the Hurricane) do you go with what you know works or gamble on something new and potentially much better?


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## Brent (Jan 10, 2022)

Thumpalumpacus said:


> Yeah, it did get a Merlin in a couple of models.
> 
> 
> 
> ...


I love that not the prom queen line!! I talking to a EAA chapter about my own P40k project and I’m gonna use it for sure!

Was it the hottest airplane we had? Maybe at first but certainly not by the end. But what 1935 design (think P-36) would still hold up by 1943? Not many other than the 109 and the P-38. 

The Brits and Aussies in North Africa and the AV G showed how capable it could be with proper handling and strategy. Saburo Sakai said that down low the P-40 was one of his roughest opponents

But is it really too draggy to ever be updated to P-51 levels. A fat wing and a whole lot of airframe drag kept even the updated versions from getting real fast. It’s kinda like comparing Babe Ruth to modern ballpayers training and equipment. For me personally the tradition and the style of the P-40 will always be an icon like the Colt 1911 and the Fender Stratocaster IMHO of course!

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## Thumpalumpacus (Jan 10, 2022)

Brent said:


> But is it really too draggy to ever be updated to P-51 levels. A fat wing and a whole lot of airframe drag kept even the updated versions from getting real fast. It’s kinda like comparing Babe Ruth to modern ballpayers training and equipment. For me personally the tradition and the style of the P-40 will always be an icon like the Colt 1911 and the Fender Stratocaster IMHO of course!



Right, it was an important waypoint on the road to more-modern fighters, and in its day was nothing to sneeze at. The Kiwis were using them creditably in 1944 in the Solomons, some American units were using them in that year in the MTO, and while the airframe was flawed by its older design and provenance, it was still able to cut a bit of mustard. It ain't a P-51 or Spit, never will be, but it hung in for a long time giving creditable service against enemies of its era.


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## SaparotRob (Jan 10, 2022)

Most perfectly adapted airframe for a shark's mouth. We were all thinking it.

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## Schweik (Jan 10, 2022)

And in some roles it was more suitable than a P-51 or Spit. But it was just not as generally useful especially for what were thought of as the most important roles (escorting heavy bombers and point defense / interceptor duties especially for England).

I think the short-hand on the P-40 was that it was originally a shock how poorly it held up to Axis aircraft, but then as we scrambled to train pilots, develop suitable tactics, and make a lot of minor improvements, it turned out that the P-40, in spite of it's one major flaw (altitude) remained surprisingly effective in almost every Theater of the war - except NW Europe - till surprisingly late. Not only the Kiwis but the Aussies and the Americans were still using them in the Pacific in 1944, the Americans used them into 1945 in Burma, the Americans used them as fighters through the middle of 1944 in Italy, and the British continued to use them (as fighter bombers) right up to the end of the war. The Soviets also used them until 1944 at least and they played an important role in key battles in 1942 (at Moscow and Leningrad). 

In fact the P-40 proved just good enough to still bite at the nadir for the Allies all over the world in 1942, and then as things improved into 1943 was one of the key types which helped take out a lot of those elite aircrews. It was crucial at the hinge-point and lasted in a useful role a bit beyond that.

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## tomo pauk (Jan 10, 2022)

Schweik said:


> Right but my real point is that they weren't slow compared to their opposition. I would also say, 360 mph in early 1942 (once they are pushing the engines a bit harder) is not slow, it's about average for a fighter. Some were faster but not necessarily in the field.



If the opposite side has aircraft doing 400 mph, like the Luftwaffe had in 1942 in the field, the 360 mph fighter is a slow fighter. Granted, not as slow as 320-330 mph Hurricane II or F4F.



Schweik said:


> My understanding is that the -33 had a slightly higher ratio, I'd have to go pull down some books to check. But for example according to this Sept 1941 data sheet, it had a critical altitude at military power of 13,600, where it is producing 1040 hp, and performance is usually still pretty good for another 2,000 feet above that. Which puts you at about 15,600
> 
> This similar chart from Dec 1942 for the P-40D/E shows a critical altitude at military power of 11,800 ft. Which puts you at 13,800 (but I think that was pushing it!). It's interesting though that the chart does show 56" Hg WEP setting for 1470 HP at Sea Level. I don't think a lot of units in the field got that memo until a bit later (like March).


The -33 impeller was turning at 8.77 times the crankshaft speed, the -39 impeller was turning at 8.80 times. A power of 1040 HP at 13600 ft is always 1040 HP at 13600 ft, whether made by the -33 or the -39.



Schweik said:


> My understanding is that there were different types of the later generation Allisons, and the variant they put on the 'Interceptor' configurations of the P-40N was the higher boost type, however the 'Fighter Bomber' type P-40N and the P-40Ms were limited to lower boost, this chart for a P-40M with the V-1710-81 shows 1360 for WEP and 1200 for takeoff. The infamous Allison Memo also mentions this, that the higher geared Allisons were going to have more trouble with high boost (due to heat, from what I gather).



Note the altitude for the WER there - sea level. It will be making more high up, as can be seen at the chart I've previously posted. The ram effect adds another 2500 ft for the rated altitude for WER power setting (57 in Hg at 3000 rpm). The Alison memo indeed warns for not over-boosting the new engines (the ones where impeller turns at 9.60 times the crankshaft rpm), and the power tables and chart show that, the new engines making ~100 HP less at low level vs. 'old' versions that could be run at 60 in Hg down low with blessing from Allison and USAAF. The 'old' S/C will also consume less power to drive, so more power is left to turn the prop.
There was no such thing as "this is a F/B P-40N, so easy on the throttle, fellas".



Schweik said:


> Right but without the second speed it would then be relatively a dog down low. As it was the P-40K was considered much faster than the P-40F below 4,000 ft.



As it should be, it had more power there. Trick was finding the answer how to gain performance, altitude and situational advantage over the enemy at all combat altitudes: the P-40 was lacking in that domain vs. the Luftwaffe, and could get at best the parity in Asia/Pacific.



Schweik said:


> But all the single speed superchargers had that problem - you pick where you want to go fast. Down low means poor at high altitude, up high means the reverse. It's just a bit less of an issue with a Spitfire because that is a much lighter aircraft (at least pre-Griffon)



Easy pick - the higher, the better.
FWIW, I was trying to note that 2-speed S/C is not be-all end-all qualifier, when we talk about 1-stage supercharged engines.

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## Shortround6 (Jan 10, 2022)

Tomo has covered just about all of the technical changes to the Allison engines. 

Some of the pilots manuals don't quite line up with the Allison factory specifications. But some of the pilot manuals tend to get a little sloppy with ram and no ram altitudes
There were some refits with changes with the backfire screens, too. But the superchargers and gear ratios stayed the same. until the 9.60 gears came along. 

But the main impeller when driven with a 8.80 (or 8.77) supercharger was only going to do so much and it didn't matter if you had the plain steel crankshaft, the shot peened crankshaft or the shot peened and nitrided crankshaft. The engine would hold up longer without breaking at low altitude but it was not going to make any more power at 12,000-15,000ft. (aside from changing out the backfire screens).

The 9.60 supercharger gears increased the temperature of the mixture and the higher temperature is what caused the caution in restricting the Pressure. An engine running 9.60 gears was always going to be operating closer to the detonation limits. 

I would note that the WER were also what the engine should make no RAM (like climbing or coming out of a steep turn) 

The P-40 also got lucky. How many threads do we have on things the Japanese could have done differently. (or what the Italians could have done differently) 
If the Japanese had looked around and realized that the Ki-43 needed to be retired at the end of 1942 then a lot of the P-40 saga against the Japanese facing Ki-44s ( or Ki-44s with big wings) would have been way different. 

The P-40N (and the L) were both attempts to lighted the plane up when they realized they weren't going to get much in the way of increased power. But with the N the difference in performance wasn't great and the trade-offs limited the actual utility of the airplanes. There were thousands of P-40Ns built (over 1/2 the production run)and no more of the 400 were hotrods were built, if that many and a number of them were converted back to normal Ns, at least somewhat. The Japanese and Italians and to some the extent the Germans, were not able to come up with next generations fighters (or even good improvements to existing generation fighters) that would have knocked the P-40s out of the feild.


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## K5083 (Jan 11, 2022)

> How many threads do we have on things the Japanese could have done differently. (or what the Italians could have done differently)



Got a big engine? Use it. Not got one? License it. Can't license it? You're screwed. Power is the key.


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## tomo pauk (Jan 11, 2022)

K5083 said:


> Got a big engine? Use it. Not got one? License it. Can't license it? You're screwed. Power is the key.



Japanese answer to the 1st question was 'yes'. However, the 'use it' part of the deal was not exactly followed through, especially for the Navy fighters.
Italian engine policy past 1935-ish was a hot mess, leaving them to a late start by 1940s, despite the licence deals with DB.


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## drgondog (Jan 11, 2022)

PAT303 said:


> Didn't matter how they were mounted, the guns were tested with the plane flying straight and level, RAAF .50's didn't work and neither did the same guns fitted to FAA F4 Martlets, we have covered this in other threads.


Actually it mattered significantly in P-51B/D. The solution to the B was addition of booster motor (from B-26 top turret IRC) to assist feed continuity uner high G, but realigning the 50 cal upight in the D solved the feed issue

I do know that RAF had to exert some cycles to sort out both feed chutes and mounts for the Mustang I and IA to solve issues with early Mustang 50 cal and 20mm.

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## PAT303 (Jan 11, 2022)

Schweik said:


> It's kind of the perpetual dilemma of the war (and speaks to the circumstances of aircraft like the P-40 and the Hurricane) do you go with what you know works or gamble on something new and potentially much better?


The Merlin only had about 1100hp available in 1938/39 so weight was a big issue.


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## BiffF15 (Jan 11, 2022)

K5083 said:


> Got a big engine? Use it. Not got one? License it. Can't license it? You're screwed. Power is the key.


Or you can do like the one communist country I know of, and build stuff without a license. Currently houses the birthplace of the Wuhan Flu...

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## drgondog (Jan 11, 2022)

BiffF15 said:


> Or you can do like the one communist country I know of, and build stuff without a license. Currently houses the birthplace of the Wuhan Flu...


Amen

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## PAT303 (Jan 11, 2022)

BiffF15 said:


> Or you can do like the one communist country I know of, and build stuff without a license. Currently houses the birthplace of the Wuhan Flu...


Oh you mean that virus of unknown origin


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## BiffF15 (Jan 11, 2022)

PAT303 said:


> Oh you mean that virus of unknown origin


Yes, it still hasn't been confirmed which room it escaped from in the Wuhan Institute of Virology.


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## pbehn (Jan 11, 2022)

PAT303 said:


> The Merlin only had about 1100hp available in 1938/39 so weight was a big issue.


With a twin blade fixed pitch prop, only around 66BHP was available on take off, revs had to be limited or the prop was stalled.


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## Peter Gunn (Jan 11, 2022)

Glue Sniffer said:


> The P-40 is in my honest opinion the most under rated fighter in the entire war...and there were lots of under rated fighter...F4F anyone? Considering it held the line before the war even started...its kill ratio is amazing...and it was flown against other nations at their peak by inexperienced American airmen *unlike the P-51D that got to hold the trophy after the p-47 and Spitfires had already demolished the Luftwaffe.*
> 
> *SNIP*


I hope you don't actually _believe_ this do you?

That's trope has been debunked more times than your average politician lies.


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## Schweik (Jan 11, 2022)

tomo pauk said:


> If the opposite side has aircraft doing 400 mph, like the Luftwaffe had in 1942 in the field, the 360 mph fighter is a slow fighter. Granted, not as slow as 320-330 mph Hurricane II or F4F.



But the Luftwaffe didn't have any 400 mph aircraft flying in the Med in 1942. With Trop filters their 109F and early G (toward the end of the year) were doing about 370-380 mph at their highest operating altitude. MC 202 was about the same or a little less. They got one squadron of Fw 190s briefly in 1943 but they were in Theater only for a short time.


tomo pauk said:


> The -33 impeller was turning at 8.77 times the crankshaft speed, the -39 impeller was turning at 8.80 times. A power of 1040 HP at 13600 ft is always 1040 HP at 13600 ft, whether made by the -33 or the -39.


As indicated on the charts I linked, the Tomahawk types were showing a higher critical altitude at military power.


tomo pauk said:


> Note the altitude for the WER there - sea level. It will be making more high up, as can be seen at the chart I've previously posted. The ram effect adds another 2500 ft for the rated altitude for WER power setting (57 in Hg at 3000 rpm). The Alison memo indeed warns for not over-boosting the new engines (the ones where impeller turns at 9.60 times the crankshaft rpm), and the power tables and chart show that, the new engines making ~100 HP less at low level vs. 'old' versions that could be run at 60 in Hg down low with blessing from Allison and USAAF. The 'old' S/C will also consume less power to drive, so more power is left to turn the prop.


Allison didn't give that blessing until Dec of 1942, the power issues with the Kittyhawks were already resolved by then (for several months) as acknowledged in the memo. But in early 1942 they did not know how far the engines could safely be pushed, and the improved bearings, crank shaft and crank cases were not delivered yet. Hence the problems with the early Kittyhawks starting in Dec *1941.*

This is the way 11 victory P-40 Ace and Squadron Leader Bobby GIbbes put it: 

_"Well it was basically the same aeroplane. We were a little disappointed when we first got the Kitty, we thought it'd be way ahead of the Tomahawk. In actual fact, it was a little bit better. One thing I personally didn't like about it was the Tomahawk had fairly high sides and you'd be sitting behind a thin sheet of metal but you felt safer. The Kittyhawk had perspex coming way down and you felt as if you were sitting up, very vulnerable, because you could see out so much. That was one feature I do remember. *However, later when we got our Kittyhawks running properly - were getting better performance - they were a better aeroplane."*_



tomo pauk said:


> There was no such thing as "this is a F/B P-40N, so easy on the throttle, fellas".


I believe there was though I don't know if this was just a bureaucratic thing (i.e. orders / policy) or literally a throttle limitation. Some of them had a wire which had to be broken to exceed a certain boost pressure. As Shortround6 often points out, the crew chief would typically know if they had been overboosting the engines (or just using WEP) when the plane landed due to scorch marks, oil leaks etc.



tomo pauk said:


> As it should be, it had more power there. Trick was finding the answer how to gain performance, altitude and situational advantage over the enemy at all combat altitudes: the P-40 was lacking in that domain vs. the Luftwaffe, and could get at best the parity in Asia/Pacific.



With the P-40, in all Theaters, they had to figure out how to contend with being attacked from above and carrying the day anyway. That is a very tall order, and it's the reason why the P-40 was considered so flawed. They worked out very specific tactics for this in the MTO, starting with just flying in pairs / figure 4 flights (which for some reason lagged in that Theater until around mid-1942) then flying in squadron formation and turning into the initial attacks as a unit (on the word of the squadron leader). And of course, using their escape maneuvers when they got into trouble.

Tactics in the Pacific and China were actually somewhat similar, except that they could extend more easily at or near co-altitude without doing a dramatic split S escape manuever and zoom climb.



tomo pauk said:


> Easy pick - the higher, the better.
> FWIW, I was trying to note that 2-speed S/C is not be-all end-all qualifier, when we talk about 1-stage supercharged engines.



Well, generally I agree, but not always. In an Allison P-40, the higher critical altitude is a tradeoff to the much higher power down low. There were definitely more Aces made flying P-40K than M. This also depended where the fighting was taking place, which is a reflection of what kind of bombers were active and what kind of targets they were going for. In the Pacific with dive and torpedo bombers the fighting was often lower, similar in the Med and Russian Front. There is a reason why they made those LF Spitfires.


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## tomo pauk (Jan 11, 2022)

Schweik said:


> But the Luftwaffe didn't have any 400 mph aircraft flying in the Med in 1942. With Trop filters their 109F and early G (toward the end of the year) were doing about 370-380 mph at their highest operating altitude



Any sources about the Bf 109F-4 and/or G-2 losing 30+- mph due to the installation of trop filters, while the P-40 seem to loose zero mph due to filter being installed?



Schweik said:


> As indicated on the charts I linked, the Tomahawk types were showing a higher critical altitude at military power.



The -33 have had greater critical altitude for the military power, it's military power being lower than on the -39 by about 100 HP. The V-1710-39 was making better power under ~13500 ft, and same power above ~13500 ft. 



Schweik said:


> With the P-40, in all Theaters, they had to figure out how to contend with being attacked from above and carrying the day anyway. That is a very tall order, and it's the reason why the P-40 was considered so flawed. They worked out very specific tactics for this in the MTO, starting with just flying in pairs / figure 4 flights (which for some reason lagged in that Theater until around mid-1942) then flying in squadron formation and turning into the initial attacks as a unit (on the word of the squadron leader). And of course, using their escape maneuvers when they got into trouble.



One of procedures was to have Spitfires flying top cover. Or, as it was the case in the ETO, not to use P-40s at all.


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## Schweik (Jan 11, 2022)

Shortround6 said:


> Tomo has covered just about all of the technical changes to the Allison engines.
> 
> Some of the pilots manuals don't quite line up with the Allison factory specifications. But some of the pilot manuals tend to get a little sloppy with ram and no ram altitudes
> There were some refits with changes with the backfire screens, too. But the superchargers and gear ratios stayed the same. until the 9.60 gears came along.



I'm well aware of all the changes done to the Allisons. The actual altitude where WEP was available varied based on atmospheric conditions, temperature etc., but it was obviously not literally at Sea Level, I think that is just a euphemism for "as low as possible" as a general guideline. This specific engine flight chart from Dec 1942 shows that War Emergency power (57" Hg) on a P-40N is available up to 7500 feet. This is with a V-1710-81 or -99, according to the chart. This 1944 RAAF test showed WEP rating (also looks like 57" again) available to 9,200 ft, and still managing 50" at 13,500 ft. The chart also shows what a huge improvement in speed that meant compared to military power (285 mph vs. 315 mph at Sea level, 315 vs 355 mph at 9200 ft., 330 vs 350 mph at 14,000 ft)



Shortround6 said:


> But the main impeller when driven with a 8.80 (or 8.77) supercharger was only going to do so much and it didn't matter if you had the plain steel crankshaft, the shot peened crankshaft or the shot peened and nitrided crankshaft. The engine would hold up longer without breaking at low altitude but it was not going to make any more power at 12,000-15,000ft. (aside from changing out the backfire screens).


See the chart referenced above!


Shortround6 said:


> The 9.60 supercharger gears increased the temperature of the mixture and the higher temperature is what caused the caution in restricting the Pressure. An engine running 9.60 gears was always going to be operating closer to the detonation limits.
> 
> I would note that the WER were also what the engine should make no RAM (like climbing or coming out of a steep turn)
> 
> ...



This is an interesting line of speculation. There was a lot of higher potential all around, that was always impacted by field conditions, political and economic realities.

Another one of the big Tropes that always settles in over all the key early / early-mid war Allied fighter types: P-40, F4F, Yak-1 and 7, Hurricane, D.520, Spit I through V etc. is that as relatively new aircraft, they suffered teething problems and needed to be adapted to field conditions. Their pilots weren't well trained in many cases (USN being somewhat of an exception, maybe RAF in England too) and new tactics had to be developed to make them work.

P-40N does 378 mph in a test in Buffalo, but then in Australia or at Boscombe down, with bomb shackles, direction finder, rear view mirror, full load of ammunition and fuel, some rivets and metal plates not smoothed over, and maybe not the cleanest paint job, it makes 355 mph.

Obviously the Japanese had the same problems. But they start the war with very well trained pilots, and some field experience in getting their new aircraft ready for battle. Same with the Germans, who also add particularly sophisticated tactics.

Later, when the Japanese are struggling with making some of their new types work on remote islands in Tropical conditions, we sometimes give them a pass. Oh if only the Ki-61s and Ki-44s were running right etc. (let alone getting a new wing!). They had the same struggles the Allied Air Forces did. Various US and Australian P-40 squadrons did indeed face Ki-44s and they didn't exactly get slaughtered. (maybe NZ too I'm not sure). The 23rd FG even seem to have done alright against Ki-84s in one encounter in China that I know of.

Of course by then, the Japanese were suffering from declining pilot quality / training. But we don't really give this same pass to the Allies in 1941-42.



Shortround6 said:


> The P-40N (and the L) were both attempts to lighted the plane up when they realized they weren't going to get much in the way of increased power. But with the N the difference in performance wasn't great and the trade-offs limited the actual utility of the airplanes. There were thousands of P-40Ns built (over 1/2 the production run)and no more of the 400 were hotrods were built, if that many and a number of them were converted back to normal Ns, at least somewhat. The Japanese and Italians and to some the extent the Germans, were not able to come up with next generations fighters (or even good improvements to existing generation fighters) that would have knocked the P-40s out of the feild.



Yeah, but this again is veering out into speculation and 'What -IFs'. The US could have gotten jets or bearcats into the Theater earlier, or developed the P-40Q. What matters though really is what happened. P-40s (not Q) turned out to be more useful in 1944 than anyone would have thought in early 1942. That's partly because they were able to work out tactics and mechanical improvements and maintenance procedures so that 'not quite good enough' (ala early 1942) was turning into ('definitely good enough') by late 1942 and most of 1943, and was still 'just about good enough' in 1944. To the surprise of many then, and I would suspect, of many people today as well.

Getting your existing, or new and improved technology working up to spec in the wretched kind of environments you would find in Rabaul or Guadalcanal is part of the whole contest. And this is one of the interesting threads of the story of aviation in WW2, I think.

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## FLYBOYJ (Jan 11, 2022)

Schweik said:


> P-40N does 378 mph in a test in Buffalo, but then in Australia or at Boscombe down, with bomb shackles, direction finder, rear view mirror, full load of ammunition and fuel, *some rivets and metal plates not smoothed* over, and maybe not the cleanest paint job, it makes 355 mph.


I get that some manufacturers did some minor mods to get their alleged "stock" products to perform better during factory tests, but please elaborate on your statement "rivets smoothed over," where is that coming from?


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## Schweik (Jan 11, 2022)

tomo pauk said:


> Any sources about the Bf 109F-4 and/or G-2 losing 30+- mph due to the installation of trop filters, while the P-40 seem to loose zero mph due to filter being installed?



I think the P-40s _did_ lose some speed due to tropical filters, just not as much. In one test I linked a P-40F had bomb shackles and still made 370 mph, but in other tests it's more like 350. One Boscombe Downe test shows ~340 mph with a Kittyhawk I (P-40D), other Australian tests a little later show 360 mph with a later P-40E. Bf 109 F performance was also down to the horsepower rating allowed etc., and the top speed regardless was at quite high altitude.

I gather figuring out what best performance for 109F and early G series was is also somewhat a work in progress, but on another thread in this forum, Greg P posted this German test of a 109F-2 indicating a top speed of 369 mph at 6km / 19,000 ft, and an F-4 at 388 mph at 8 km / 26,000 ft. I don't think that is with Tropical filters.

I see later in that thread someone noting that an F-4 was cleared for 394 mph at 22k ft in Feb 1942 (clean, i.e. with no Trop filter). A later test (from 1943) you posted says 635 km / hr (416 mph) but I'm not sure when that was achieved in the field, let alone with Tropical filters.

I don't know exactly how much speed the 109F or G-2 lost due to their Tropical filter, except that anecdotally the German pilots mentioned it was significant. The Spit V as we know, lost about 20-30 mph.



tomo pauk said:


> The -33 have had greater critical altitude for the military power, it's military power being lower than on the -39 by about 100 HP. The V-1710-39 was making better power under ~13500 ft, and same power above ~13500 ft.


Hmmm, I'll have to look at the charts again, maybe I misread it.



tomo pauk said:


> One of procedures was to have Spitfires flying top cover. Or, as it was the case in the ETO, not to use P-40s at all.



They would have done this more often, but the Spit V had very limited range, even more so with the Vokes filter. In the MTO it was only used for airfield defense and other missions very close to base. For attacking the German air bases they typically had to use older P-40s and Hurricanes escorted by newer (i.e. F/L or M) P-40s flying top cover. The Spitfires available in Theater were not even flying on most mission days for example during El Alamain, in Oct -Nov 1942 (about half the days, vs. almost every day for the P-40 units). I posted a long detailed breakdown of this in another thread on here a couple of years ago.

Spit Vs also didn't have super high altitude performance, compared to a Merlin P-40. Both the Spit and P-40 units had to contend with attacks from above by Luftwaffe units and had to use similar tactics. P-38s potentially could do better but they seem to have been dealing with various issues in the Med, and I'm not an expert on that type so I won't say more than that.

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## Schweik (Jan 11, 2022)

FLYBOYJ said:


> I get that some manufacturers did some minor mods to get their alleged "stock" products to perform better during factory tests, but please elaborate on your statement "rivets smoothed over," where is that coming from?



My language wasn't super precise, but I assumed the meaning was clear- 'rivets smoothed over' isn't meant literally. What I mean is that the physical condition of the aircraft varying from relatively rough to relatively pristine, made a notable difference in speed.

In the official AVG memoir they mentioned that one of their Tomahawks tested at a top speed of 348 mph, and after they carefully went over it, stripped the paint off, repainted, sanded and the waxed it, and made several minor repairs to the body where there were seams or gaps in the plates (some filled with some kind of putty), including replacing some rivets and so on, they got the speed up to 359 mph. An 11 mph improvement. And I've read similar anecdotes from many other Theaters and types of aircraft.

I'm sure you know this much better than I do, but looking closely at warbirds today at airshows and museums, you can see seams between panels, or panels raised a bit one over the other, which are wider than you would normally have on a car. All of this causes drag, and these aircraft today, are (at least the flying ones) fairly pristine compared to some in the field in places like Port Morseby (let alone say, some rural field in Russia). Many aircraft would for example have patched bullet or flak holes on the wings or fuselage. Some had major parts from another aircraft bolted on.

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## FLYBOYJ (Jan 11, 2022)

Schweik said:


> My language wasn't super precise, but I assumed the meaning was clear- 'rivets smoothed over' isn't meant literally. What I mean is that the physical condition of the aircraft varying from relatively rough to relatively pristine, made a notable difference in speed.
> 
> In the official AVG memoir they mentioned that one of their Tomahawks tested at a top speed of 348 mph, and after they carefully went over it, stripped the paint off, repainted, sanded and the waxed it, and made several minor repairs to the body where there were seams or gaps in the plates (some filled with some kind of putty), including replacing some rivets and so on, they got the speed up to 359 mph. An 11 mph improvement. And I've read similar anecdotes from many other Theaters and types of aircraft.
> 
> I'm sure you know this much better than I do, but looking closely at warbirds today at airshows and museums, you can see seams between panels, or panels raised a bit one over the other, which are wider than you would normally have on a car. All of this causes drag, and these aircraft today, are (at least the flying ones) fairly pristine compared to some in the field in places like Port Morseby (let alone say, some rural field in Russia). Many aircraft would for example have patched bullet or flak holes on the wings or fuselage. Some had major parts from another aircraft bolted on.


OK - because there have been some references to operators "grinding down" rivet heads to assist in getting more speed out of aircraft. This is something that is never done in normal maintenance operations as it destroys the strength of the rivet(s). The only means of removing material from a rivet is done with flush head rivets and a micro shaver. Sometimes you can have gapped heads on rivets that can be replaced helping the effort.

There have been many stories about surface improvements in the field in an attempt to get a few MPH out of an aircraft, but as stated, in a wartime scenario, this can only be done for so long as the pace of combat eclipses the time and need to maintain these mods.

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## Schweik (Jan 11, 2022)

Yeah in general, I don't think they usually could maintain those kinds of high 'grooming' standards for warplanes. They would do things like that for a fighter (or bomber) being used for photo recon missions to get a little more speed out of it, or sometimes when a given aircraft was deemed as losing some performance they would give it a once over. Or more rarely, for a whole unit that was say, flying top cover against very fast opposing aircraft and really needed the edge. 

Conversely, routinely used aircraft often had all kinds of issues. I've seen wartime photos where there are holes in aircraft that are apparently operational and haven't been filled in. It all depends on the circumstances.

Also I think people don't always realize, the pace of production for wartime materiel often meant that they didn't put the kind of finish on them that you would get in a civilian vehicle. You see this with tanks and armored vehicles too. 

With aircraft, it's a balancing act. It needs to be made to withstand bullets and high G forces, and be 'clean' enough to fly without too much drag, but at the same time, many of them are going to be destroyed shortly after they reach their destination combat zone (some before they even get there). It's only the fact that they were made to be so tough that some of them are still flying today (with a lot of maintenance and rebuilding etc.)

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## FLYBOYJ (Jan 11, 2022)

Schweik said:


> Yeah in general, I don't think they usually could maintain those kinds of high 'grooming' standards for warplanes. They would do things like that for a fighter (or bomber) being used for photo recon missions to get a little more speed out of it, or sometimes when a given aircraft was deemed as losing some performance they would give it a once over. Or more rarely, for a whole unit that was say, flying top cover against very fast opposing aircraft and really needed the edge.
> 
> Conversely, routinely used aircraft often had all kinds of issues. I've seen wartime photos where there are holes in aircraft that are apparently operational and haven't been filled in. It all depends on the circumstances.
> 
> ...


Well aware of all this, I've been building and maintaining aircraft (to include warbirds) for over 40 years - with that said, you cannot compare aircraft finishes (especially combat aircraft) to what you have on an automobile (maybe corporate aircraft in today's world). Additionally during WW2 there were finish and "gap and mismatch" requirements on production aircraft. After construction, an aircraft was test flown (production test flight) and there was a tolerance of performance that was required to be achieved. If that didn't happen, the unit wasn't accepted.

The perfect example of this were some of the Corsairs built by Brewster.

_Unable to meet demand, Vought licensed production to Brewster in November 1941 and to Goodyear Aircraft Corporation one month later. Brewster built 735 Corsairs, with 430 going to the Royal Navy's Fleet Air Arm.

Brewster as a company never reached its potential. Its reputation for poor quality carried over to the license-built Corsairs. Reports from pilots differed as to how well Brewster Corsairs compared to the Vought aircraft. None of the Brewster Corsairs went to front line combat units during the War.

The US Navy closed Brewster's production line at the end of June 1944 because the company was continually behind schedule building the much-needed Corsair, much of it due to labor unrest and strikes._









Brewster F3A Corsair - National Museum of World War II Aviation


This Navy Corsair was built by Brewster and Co., Aircraft Division, in Long Island City, NY. The company produced military aircraft from the 1930s until the end of WWII. In 1940, the Vought aircraft company designed one of the best all-around Navy fighters of the…




www.worldwariiaviation.org

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## Schweik (Jan 11, 2022)

One thing the US firms seemed to excel at compared to many others, is standardization and interchangeability of parts. Apparently a lot of the Japanese and Russian aircraft basically had 'bespoke' parts, some of the earlier British planes too.

Brewster is a sad story, they seem to have both management and labor problems. It happens with firms all the time to this day. It was certainly becoming an issue with Curtis toward the end of the war and there are notes about production quality issues with later model P-40s in some of the tests on WWIIaircraftperformance, with a notably ed tone from the testing officers. I think this is another reason why they decided not to go with the further development of the P-40 like the P-40Q.

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## wuzak (Jan 11, 2022)

Schweik said:


> The US could have gotten jets or bearcats into the Theater earlier, or developed the P-40Q. What matters though really is what happened. P-40s (not Q) turned out to be more useful in 1944 than anyone would have thought in early 1942.



Any aircraft is more useful than no aircraft.

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## Schweik (Jan 11, 2022)

And an aircraft that flys, and shoots, is better than one sitting in the hangar. I think that's part of it. But there is also a notable difference between say, P-39* or Hurricane units in 1943 or 44 vs. P-40s, especially in any air combat against enemy fighters.

* Except in Russia!

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## pbehn (Jan 11, 2022)

FLYBOYJ said:


> I get that some manufacturers did some minor mods to get their alleged "stock" products to perform better during factory tests, but please elaborate on your statement "rivets smoothed over," where is that coming from?


At least one manufacturer built in to their "stock product" a much higher level of smoothness and panel fit as standard which made the P-40 dog rough by comparison, I read about it in a book on a Bastard Stepchild so I am reluctant to give details.

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## Schweik (Jan 11, 2022)

North American Avitaion?

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## Schweik (Jan 11, 2022)

Thank God that German was working for us!


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## pbehn (Jan 11, 2022)

Schweik said:


> Another one of the big Tropes that always settles in over all the key early / early-mid war Allied fighter types: P-40, F4F, Yak-1 and 7, Hurricane, D.520, Spit I through V etc. is that as relatively new aircraft, they suffered teething problems and needed to be adapted to field conditions. Their pilots weren't well trained in many cases (USN being somewhat of an exception, maybe RAF in England too) and new tactics had to be developed to make them work.
> 
> P-40N does 378 mph in a test in Buffalo, but then in Australia or at Boscombe down, with bomb shackles, direction finder, rear view mirror, full load of ammunition and fuel, some rivets and metal plates not smoothed over, and maybe not the cleanest paint job, it makes 355 mph.


This is the origin of an early strand in groundhoggery. The RAF were not interested in a stripped down, souped up, puttied and sanded aircrafts top speed, the performance figure is only useful in a post war discusssion forum. They were interested in how a combat aircraft performed in standard condition. They understood that armour, self sealing tanks, cannon, aerials etc cost speed and climb, but put up with it because that was what was needed on a war plane, which wasnt a Reno racer. Some manufacturers cried foul as if the client doesnt know what it wanted, others like Supermarine and NAA did what the client asked. When the USA entered the war, their aircraft all carried the "stuff" that the RAF had demanded so there is no doubt what was the correct approach.

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## Schweik (Jan 11, 2022)

Right, and that certainly makes sense. Generally I think this is the wisest approach. Sometimes those Boscombe Downe tests erred on the conservative side a bit, as in using very low boost levels and high weight, especially for foreign planes. But I still think it's the wisest way to do the testing.

One other counterpoint is, quite often planes were eventually 'souped up' (used at higher boost ratings etc.), including Spitfires. The higher speed under 'best conditions' including sanding, higher boost and all the rest, gave them an idea of the _potential _of the airframe when certain changes were made... changes which might be out of reach at first but became attainable later. This was incorporated for example in the Spitfire when they put the bulletproof window inside, fared over the rearview mirror and so on. Sometimes small changes could be made to reduce drag and improve performance. With regard to the Merlin P-40, they made about a 20 mph difference by the field stripping and 'cleaning up' they did in the field in North Africa. And that did make a difference, apparently, or they wouldn't have been flying any of those aircraft with four guns.

And to this point, it's also worth monitoring how the performance is coping with the increasing amounts of 'stuff', because quite often there is a tipping point which occurs with a difference of just a couple of hundred pounds where performance falls off quite a bit. That is when it's time to re-evaluate either the design or how much gear you are trying to hang on it.

There is no doubt there was a wide range in actual performance under field conditions, vs the ideal performance under perfect conditions, and I wish that was a bit better covered and disseminated by the aviation literature and online resources. We tend to get kind of a random variation with some types showing 'ideal' performance numbers and / or speed with high boost, and others showing numbers based on field conditions + relatively low power. I think this is going to be the subject of another thread I want to start here one day (how to reform the basic 'stat block', including breaking down the different variants better)

When it comes to extreme cases, for example Russian early planes with very rough build quality and pilots flying with the canopy open or removed altogether because it was too difficult to open in an emergency, the speed difference might be as much as 50 mph or more off of the the theoretical baseline. Famous 'field mods' like extra gunpods on Stukas or Hurricanes also imposed a very harsh toll on top speed, though I don't know precisely how much because it's rarely published.


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## Schweik (Jan 11, 2022)

I think the Australian tests are an interesting compliment to the Boscombe Down tests. They tested under field conditions where they were, and the results were often surprising.


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## pbehn (Jan 11, 2022)

Schweik said:


> One other counterpoint is, quite often planes were eventually 'souped up' (used at higher boost ratings etc.), including Spitfires. The higher speed under 'best conditions' including sanding, higher boost and all the rest, gave them an idea of the _potential _of the airframe when certain changes were made... changes which might be out of reach at first but became attainable later. This was incorporated for example in the Spitfire when they put the bulletproof window inside, fared over the rearview mirror and so on. Sometimes small changes could be made to reduce drag and improve performance. With regard to the Merlin P-40, they made about a 20 mph difference by the field stripping and 'cleaning up' they did in the field in North Africa. And that did make a difference, apparently, or they wouldn't have been flying any of those aircraft with four guns.


There are many types of test. A product acceptance test is in the as delivered condition. Other tests to determine the effect of changes are a different story. The RAF and Supermarine conducted tests for all sorts of reasons, like producing a Spitfire with all flush rivets, covering them with split peas and progressively removing them to see how speed was affected. Flush riveting is more expensive and takes more time, so it was really an experiment in how many more Spitfires could be produced without badly affecting their performance. Testing at higher boost levels was done to verify the engine changes. If you randomly just use more boost than recommended in the field without the appropriate new engines and fuels you can quickly end up with no airforce.

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## Schweik (Jan 11, 2022)

pbehn said:


> There are many types of test. A product acceptance test is in the as delivered condition. Other tests to determine the effect of changes are a different story. The RAF and Supermarine conducted tests for all sorts of reasons, like producing a Spitfire with all flush rivets, covering them with split peas and progressively removing them to see how speed was affected. Flush riveting is more expensive and takes more time, so it was really an experiment in how many more Spitfires could be produced without badly affecting their performance. Testing at higher boost levels was done to verify the engine changes. If you randomly just use more boost than recommended in the field without the appropriate new engines and fuels you can quickly end up with no airforce.



True, but you can (and did) also end up with no Air Force by flying according to the manual / SOP, and sometimes you had to push the envelope a bit. As many units in fact did. There was a sweet spot between manufacturers recommendations and the conditions in the field (and capability of the enemy!)

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## FLYBOYJ (Jan 11, 2022)

Schweik said:


> True, but you can (and did) also end up with no Air Force by flying according to the manual / SOP, and sometimes you had to push the envelope a bit. As many units in fact did. There was a sweet spot between manufacturers recommendations and the conditions in the field (and capability of the enemy!)


And there was a guy called the *Maintenance Officer* who generally made that decision. At the same time a pilot could refuse to fly an aircraft if he deemed it unairworthy.

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## Shortround6 (Jan 11, 2022)

In a chart on page 124 in "Vees for Victory" they have a chart for the V-1710-33 The chart is dated 12-5-39.
the chart is _something like_ this one.






EXCEPT, it shows the graph going all the way to sea level. It is also in finer detail and has standard latitude and temperature along the bottom.

The engine is shown as making 1090hp/3000rpm at 13,200ft using 38.9in. in notes similar to the ones in the chart using as the illustration. 
The chart shows that the engine will make 1040hp at 14,200ft.
The engine will also make 1150hp at around 11,500ft. using 42in?
The engine will also make just under 1700hp at sea level using 61in map.

There was considerable argument about the C-33 between Allison and the Air Corp. Allison wanted the 1040hp rating and the Air Corp wanted the 1090hp rating. The Air Corp got the 1090hp rating but they broke of lot engines and Allison had to rebuild 277 engines and the engines still flying were derated to 2770rpm and 950hp at 8,000ft. The modified engines were rated at 1090hp.

Now please note that the 1040hp rating does show up in quite a few books/sources about the P-40.

BTW the chart shows the C-33 engine was good for about 1480hp at 42-4300ft using 54in and 1580hp at 2500ft using 58in which is not too bad considering changes in manifolds, backfire screens and a few other minor differences.

These are test results and are NOT useable for service use


Now even climbing or putzing along at 180mph there is going to be some RAM effect.
Ram effect in theory goes up with the square of the speed. However RAN effect in the engine charts also take into account any limitations in the intake duct duct or problems with the intake.
Also note that P-40s and P-39s (and perhaps Allison P-51) had to have their exhaust pipes modified to get the full effect of the WER performance. The Exhaust pipes were too small and were choking the engine, the exhaust outlets had to be opened up.

Corrected 1580hp at 2500ft in C033 chart

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## Schweik (Jan 11, 2022)

Interesting about the exhaust pipes, I hadn't heard that. I know they eventually changed to fishtail stacks on the P-40s (but I thought that was a bit later, late 42?) and the Mustangs went through various changes.

Do you have a larger / higher-res version of that chart? I can't read it.


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## Shortround6 (Jan 11, 2022)

That chart is from the IL-2 Sturmovik forum. 

It shows some of the information that the the Chart in "Vees for Victory" shows but not all. 

There are several charts for Allison's of different models in the book but there is at least one misprint with a wrong chart showing up next to a caption. 


I believe the exhaust stacks were were cut a different angle in order to increase the exhaust opening. After all, if you are trying to shove 28% more fuel/air (1490hp vs 1150hp) into the engine you need to let the exhaust out. This could actually be done with a hacksaw. It also screws things up slightly for high altitude work as at 15,000 to 20,000ft (and above) you are not getting quite same exhaust gas velocity as the would for the unmodified exhaust. Your exhaust thrust is mass X veleocity.

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## Schweik (Jan 11, 2022)

Gotcha


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## tomo pauk (Jan 11, 2022)

Shortround6 said:


> In a chart on page 124 in "Vees for Victory" they have a chart for the V-1710-33 The chart is dated 12-5-39.
> the chart is _something like_ this one.
> 
> 
> ...





Schweik said:


> Do you have a larger / higher-res version of that chart? I can't read it.



That chart was taken from the manual for Mustang I, showing the V-1710-39 engine. Big pic, not edited (click for hi-res):

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## Shortround6 (Jan 11, 2022)

The book may have a chart for the Allison used in the A-36 as well the Allison using the 9.60 gears. 

Some of the figures for the WEP ratings don't agree with the charts.

The WEP power for the A-36 engine (-87) is barley attainable with NO RAM at sea level (1500hp) let alone 5,400ft unless you are using a lot of RAM or are over speeding the engine (3200rpm?). Granted the chart is labeled "estimated Altitude performance" but again, RAM covers a variety of conditions. An Allison powered Mustang could do around 340-350mph at sea level using military power. However at max rate of climb it was around 170mph (or under) so your engine chart for RAM is going to show no RAM (unrealistic) and RAM for maxim speed(?) or some comprise?


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## Admiral Beez (Jan 11, 2022)

denny said:


> What was lacking in the P-40 that made the Allies decide not to upgrade it with a Merlin Engine.?
> Or maybe it was done and the P-40 proved wanting in some area(s).?
> Thank You


I expect if in 1941 you'd asked the VVS if they'd swap all their Yak-1, MiG-3 and LaGG-3 fighters with Curtiss P-40s they'd have jumped at the opportunity. Nothing wrong with the P-40 in the early war years. 

As for not sticking a Merlin on it, that wasn't an idea until the British got hold of the Allison-powered Mustang, but which time the P-40 was less competitive. Why stick your limited Merlins onto the P-40 when they can go on the Mustang?


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## Schweik (Jan 11, 2022)

Yes the Soviets did fairly well with the P-40s and considered them good up to the end of 1943, though they much preferred the P-39. They seem to have had more engine trouble with the P-40s (both due to cold weather and dust / dirt)


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## tomo pauk (Jan 11, 2022)

Shortround6 said:


> The book may have a chart for the Allison used in the A-36 as well the Allison using the 9.60 gears.



Power chart for the V-1710-81 engine, IIRC from the Perli's P-40s website.
(my comment - this represents the best-case scenario, ie. engine is without backfire screens since it had the 'Madam Queen' venturis in the intake? note that chart gives rated altitude of 15500 ft for mil power [1150 HP], while the two available tables give 14500 ft for the same thing)

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## Schweik (Jan 11, 2022)

Unless I'm reading that wrong it looks like power tops out at less than 1300 hp? But they aren't indicating any WEP / WER...


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## Shortround6 (Jan 11, 2022)

Admiral Beez said:


> I expect if in 1941 you'd asked the VVS if they'd swap all their Yak-1, MiG-3 and LaGG-3 fighters with Curtiss P-40s they'd have jumped at the opportunity. Nothing wrong with the P-40 in the early war years.
> 
> As for not sticking a Merlin on it, that wasn't an idea until the British got hold of the Allison-powered Mustang, but which time the P-40 was less competitive. Why stick your limited Merlins onto the P-40 when they can go on the Mustang?


Well, at least they would have radios,

The was a lot wrong with the P-40s in 1941, But then there was a lot wrong with the Russian fighters. 

Allison doesn't build with Allison that could withstand until WEP (even unofficially) until about Dec of 1941. That to when the change over to the "new" crankshaft and crankcase occurred (as opposed to the change over from the original crankshaft and crankcase of 1940 and the sort of new crankshaft and crankcase that used from late 1940 through most of 1941. 
You could use a lot of boost in the early Allisons, you just didn't know when they were going to quit on you.

The Lagg-3 was overweight but so was the P-40. You are going to need to find climb performance and turn numbers. The P-40 had a big wing and it was fast (better build quality) but there wasn't much you could do about the climb unless you tried hacking some weight out of it. (don't fill the fuel tanks, yank some of the guns out, don't carry full ammo, etc)


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## Schweik (Jan 11, 2022)

There is an article "P-40 in Soviet Service" which goes through their early experience with the Tomhawk / P-40B/C (which IIRC they got by Sept 1941) and then later Kittyhawk types. I'm sure you are familiar with it. It seems from that article to have come in quite handy, and they felt it could handle the 109s they were facing, even though they had a lot of trouble with keeping the engines running. They considered it superior to the LaGG-3, the Hurricane and MiG but not the Yak 1 or 7.

Excerpt:

_"Despite these problems, active combat continued. In January some 198 aircraft sorties were flown (334 flying hours) and 11 aerial engagements were conducted, in which 5 Bf-109s, 1 Ju-88, and 1 He-111 were shot down [6]. These statistics reveal a surprising fact – it turns out that the Tomahawk was fully capable of successful air combat with a Bf-109. The reports of pilots about the circumstances of the engagements confirm this fact. On 18 January 1942, Lieutenants S. V. Levin and I. P. Levsha (in pair) fought an engagement with 7 Bf-109s and shot down two of them without loss. On 22 January a flight of three aircraft led by Lieutenant E. E. Lozov engaged 13 enemy aircraft and shot down two Bf-109Es, again without loss. Altogether in January two Tomahawks were lost-one shot down by German antiaircraft artillery and only one by Messerschmitts.

However, the Tomahawk was a frequent target of friendly fire – an unfamiliar aircraft engaged in the heat of battle by both Soviet fighters and antiaircraft artillery. This normally resulted in scores of bullet holes and apologies, but around New Years Day Soviet PVO outdid itself: five I-16s, and later antiaircraft gunners, attacked the Tomahawk AN507 of Junior Lieutenant P. G. Maz. He made a forced landing, resulting in heavy damage to the engine, and the aircraft was sent off for repairs.

But the primary source of losses was mechanical failures. Practically not a single combat sortie was flown without some kind of problem. It was a common practice to land with a dead engine. Not all of these flights were completed successfully. On 17 February 1942, one of the best pilots of the regiment, HSU Senior Lieutenant S. G. Ridnyy (Tomahawk AK325) suffered an engine failure on takeoff and was killed in crash. Despite this abundance of accidents and incidents, the general impression of the pilots of 126th IAP regarding this aircraft remained good. The Tomahawk had qualities that were lacking in aircraft of Soviet production._"

Kittyhawks were even more useful especially the K model. They had at least a couple dozen pilots who made Ace flying Kittyhawks, and three or four triple or quadruple aces and HSU. I've quoted some of Nikolai Golodnikov's comments on the type which I know you've seen. They played a significant role at Leningrad and were also in action at Moscow.

Here is a link to the interview somebody posted on a War Thunder forum.

Brief excerpt:

_"*How would you rate the speed, climb rate, acceleration dynamics, maneuverability of P-40? Did you like it?*

- Again, the P-40 was much superior and the "Hurricane", and I-16, was much higher.

Strictly speaking, with all types of "Messers" P-40 fought on an equal level, almost to the end of 1943. If we take the whole complex of performance, then the P-40 Tomahawk was equal to Me-109F, and the Kittyhawk is slightly better. Speed, vertical and horizontal maneuverability were good, with enemy aircrafts quite comparable. On the dynamics of acceleration, the P-40 was a bit heavy, but when you adjust to the engine, it's normal.

When later types of Me-109G and FW-190 went, the P-40 "Kittyhawk" began to yield a little, but not much. An experienced pilot fought with them equal. At P-40, I spent 10-12 air battles and a total of about 50 sorties. Then the regiment once again changed to the P-39 "Aerocobra"_."

Most of the P-40 units in the VVS became Guards units. Most eventually switched to P-39, La 5 series or Yak 9.

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## Schweik (Jan 11, 2022)

Golodnikov mentions they flew at higher RPMs and removed some guns from their fighters to lighten them, to get the performance up sufficiently to deal with 109s. He also says engines were burning out after ~ 50 hours. Compared to the life span of an I-16 or LaGG-3 it may make sense.

But they gradually figured out how to deal with Allison (and Merlin) engines better as time went on.


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## BiffF15 (Jan 11, 2022)

Schweik said:


> Golodnikov mentions they flew at higher RPMs and removed some guns from their fighters to lighten them, to get the performance up sufficiently to deal with 109s. He also says engines were burning out after ~ 50 hours. Compared to the life span of an I-16 or LaGG-3 it may make sense.
> 
> But they gradually figured out how to deal with Allison (and Merlin) engines better as time went on.


Sounds like they were pushing the engines beyond the book if they were consistently getting 50 hours out of them, and losing so many a/c for mechanical problems. And with that they thought it was a better plane than the indigenous stuff.

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## tomo pauk (Jan 11, 2022)

Schweik said:


> Unless I'm reading that wrong it looks like power tops out at less than 1300 hp? But they aren't indicating any WEP / WER...



I'm shocked. How dare they?

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## SaparotRob (Jan 11, 2022)

BiffF15 said:


> Sounds like they were pushing the engines beyond the book if they were consistently getting 50 hours out of them, and losing so many a/c for mechanical problems. And with that they thought it was a better plane than the indigenous stuff.


What were the VVS paying for the P-40?

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## Thumpalumpacus (Jan 11, 2022)

SaparotRob said:


> What were the VVS paying for the P-40?



I've done some hurt on a Hertz, too. Ain't my engine.

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## wuzak (Jan 11, 2022)

Shortround6 said:


> BTW the chart shows the C-33 engine was good for about 1480hp at 42-4300ft using 54in and *5800hp at 2500ft using 58in* which is not too bad considering changes in manifolds, backfire screens and a few other minor differences.



Wow. Why didn't the P-39 get that engine? It would have been a world beater with that power!

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## Shortround6 (Jan 11, 2022)

wuzak said:


> Wow. Why didn't the P-39 get that engine? It would have been a world beater with that power!


it wouldn't fit because the nose armor got in the way.

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## wuzak (Jan 11, 2022)

Schweik said:


> Right, and that certainly makes sense. Generally I think this is the wisest approach. Sometimes those Boscombe Downe tests erred on the conservative side a bit, as in using very low boost levels and high weight, especially for foreign planes. But I still think it's the wisest way to do the testing.



I do believe that Boscombe Down performed performance tests and tactical trials of production aircraft using representative weights and ran them according to the operating manuals.

They also checked performance gains when additional boost was cleared for an engine type.




Schweik said:


> One other counterpoint is, quite often planes were eventually 'souped up' (used at higher boost ratings etc.), including Spitfires. The higher speed under 'best conditions' including sanding, higher boost and all the rest, gave them an idea of the _potential _of the airframe when certain changes were made... changes which might be out of reach at first but became attainable later. This was incorporated for example in the Spitfire when they put the bulletproof window inside, fared over the rearview mirror and so on. Sometimes small changes could be made to reduce drag and improve performance. With regard to the Merlin P-40, they made about a 20 mph difference by the field stripping and 'cleaning up' they did in the field in North Africa. And that did make a difference, apparently, or they wouldn't have been flying any of those aircraft with four guns.



They tested aircraft at higher engine ratings when the higher engine ratings were cleared for use. And for that the engines had to go through separate testing.

The internal armour screen was not an example of a "souped up" aircraft, but a reflection of production changes.


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## Shortround6 (Jan 11, 2022)

I would note that one of these accounts of the early Soviet P-40s says that there were no spare engines and the Soviets re-engined about 40 P-40s with M-105P engines and that reduced the speed by about 12kph. Most of the planes with M-105P engines were transferred to another regiment. The account does seem to have a misprint in regards to speed (477KPH?) but without the altitude it is very difficult to judge. 

The Russians were in desperate circumstances. They were often worried about what was going to happen in few days or few weeks. Air Forces in other parts of the World may have taken a somewhat longer view. Burning through your stock of available engines in a few weeks for gain a temporary advantage might be a good tactic, It might be a poor one if your enemy can resupply when you can't and you have no spare engines. 

P-40s rarely supplied more than a couple of regiments at a time in the same front. 

The US screwed up in 1942/43 buy not suppling enough Merlins for the P-40Fs and Ls and the British gave hundreds of Used Merlins to the US in NA/Med to be used as donner engines for overhauls.

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## BiffF15 (Jan 11, 2022)

SaparotRob said:


> What were the VVS paying for the P-40?


Exactly.

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## BiffF15 (Jan 11, 2022)

Thumpalumpacus said:


> I've done some hurt on a Hertz, too. Ain't my engine.


It's been said many times, on TDY, that you can't die in a rent a car...

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## FLYBOYJ (Jan 11, 2022)

Schweik said:


> quite often planes were eventually 'souped up' (used at higher boost ratings etc.)


Souped up? No, just a change in operating parameters maybe based on a factory modification or the manufacturer allowing higher operating parameters based on field data. "Souping Up" an engine (speaking in terms of an aircraft engine) is changing something in the basic design to enhance performance, usually outside the manufacturer's specifications (oversize pistons, tighter clearances, etc.)


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## Shortround6 (Jan 11, 2022)

BiffF15 said:


> Exactly.


I would note that the Russians had a strange incentive plan for P-40 pilots.
If the unit did well in combat (and if they lived) they got to trade in their P-40s for Yaks or La-5s or P-39s.
If they did not distinguish themselves in combat (and kept the P-40s running  ) they just got some replacement P-40s.

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## BiffF15 (Jan 11, 2022)

Shortround6 said:


> I would note that the Russians had a strange incentive plan for P-40 pilots.
> If they unit did well in combat (and if they lived) they got to trade in their P-40s for Yaks or La-5s or P-39s.
> If they did not distinguish themselves in combat (and the P-40s running  ) they just got some replacement P-40s.


Interesting plan. No motive to burn out the motors at all. And after surviving to the upgraded aircraft, they give you a ground hog. Can't win for losing.

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## special ed (Jan 11, 2022)

Schweik said:


> Golodnikov mentions they flew at higher RPMs and removed some guns from their fighters to lighten them, to get the performance up sufficiently to deal with 109s. He also says engines were burning out after ~ 50 hours. Compared to the life span of an I-16 or LaGG-3 it may make sense.
> 
> But they gradually figured out how to deal with Allison (and Merlin) engines better as time went on.


One of my books on Russian aircraft said the Russian pilots flew everywhere at full throttle. With my failing memory, I can't remember which book, so much reading is required. Now days when I find something noteworthy while reading, I put in a bookmark. My books are beginning to look like cactus plants.

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## Shortround6 (Jan 11, 2022)

FLYBOYJ said:


> Souped up? No, just a change in operating parameters maybe based on a factory modification or the manufacturer allowing higher operating parameters based on field data. "Souping Up" an engine (speaking in terms of an aircraft engine) is changing something in the basic design to enhance performance, usually outside the manufacturer's specifications (oversize pistons, tighter clearances, etc.)


The Merlins went through a number of changes but as FLYBOYJ says, there weren't souped up. 
The Merlin 45 started at 9lbs boost and very soon went to 12lbs boost. After they proved they could take it ( didn't break very often) they were approved to use 15/16lbs boost.
A similar change followed the Merlin XX. 
The only "souping" up they did was to modify the supercharger drive in order to take the increased mechanical load on the supercharger drive shaft. 

A Merlin 45 made the same amount of power at 20,000ft if it was rated for 9lbs of boost or if it was rated at 16lbs but it could only hold 16 lbs to 13,000f in high speed flight.


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## Thumpalumpacus (Jan 11, 2022)

BiffF15 said:


> It's been said many times, on TDY, that you can't die in a rent a car...



We did things to vans signed out from the motor pool that we'd never do to our own POVs.

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## Schweik (Jan 11, 2022)

BiffF15 said:


> Sounds like they were pushing the engines beyond the book if they were consistently getting 50 hours out of them, and losing so many a/c for mechanical problems. And with that they thought it was a better plane than the indigenous stuff.



There was some of that, but apparently the real reason for the short engine life was that they were maintenance issues with the engines. First, the Soviet ground crews were not used to the 'oil culture' requirements of the Merlin (for Hurricanes, at that time, later for Spitfires) and for the Allisons. Soviet engines were apparently much more tolerant of dust. Second, they had to winterize the engines, including for example making provisions to drain *all* fluids from the engines and other aircraft systems every night during winter, which in some cases meant creating drains where there weren't any. They get into a bunch of this in the article. 

From my understanding, they eventually figured a lot of this out, in part during the extensive work-up they did on the P-39.


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## Schweik (Jan 11, 2022)

SaparotRob said:


> What were the VVS paying for the P-40?



Actually, per the article:

"The first batch of Tomahawks from the USA was sent to the USSR in September 1941. *This shipment was purchased for gold* and was not part of the Lend-Lease program, the provisions of which were extended to the Soviet Union only on 7 November of that year."

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## Schweik (Jan 11, 2022)

Shortround6 said:


> I would note that one of these accounts of the early Soviet P-40s says that there were no spare engines and the Soviets re-engined about 40 P-40s with M-105P engines and that reduced the speed by about 12kph. Most of the planes with M-105P engines were transferred to another regiment. The account does seem to have a misprint in regards to speed (477KPH?) but without the altitude it is very difficult to judge.


My understanding is that the M-105P engined P-40s were not deemed suitable for front line combat and were relocated to training or PVO units.



Shortround6 said:


> The Russians were in desperate circumstances. They were often worried about what was going to happen in few days or few weeks. Air Forces in other parts of the World may have taken a somewhat longer view. Burning through your stock of available engines in a few weeks for gain a temporary advantage might be a good tactic, It might be a poor one if your enemy can resupply when you can't and you have no spare engines.


Exactly. The situation was dire in 1941 and certainly the first half of 1942. It was not unusual to send off say, a unit of 12 I-16s or LaGG-3s and have 2 or 3 come back. If they had a squadron of 12 Tomahawks and were only losing 1 or 2 per mission, (half to mechanical failure) and most of the pilots were surviving, that was still a plus even if they only made it a dozen missions or so before they needed an engine overhaul or a new engine.

They did also sort these problems out as I already mentioned, so that they were getting much longer running time out of Allisons later in the war.

Apparently there were also similar engine problems in the Western Desert in the early days, which is why the adapted the Vokes filter etc. I gather the Germans had problems with engines burning out too.



Shortround6 said:


> P-40s rarely supplied more than a couple of regiments at a time in the same front.



As I mentioned, most of the P-40 units were made into Guards units and they were put into the heaviest fighting in some zones, though some were up near Finland.



Shortround6 said:


> The US screwed up in 1942/43 buy not suppling enough Merlins for the P-40Fs and Ls and the British gave hundreds of Used Merlins to the US in NA/Med to be used as donner engines for overhauls.



True. They had a limited number but worked out a clever system for engines and spares pretty quickly, largely via the British.


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## wuzak (Jan 11, 2022)

Shortround6 said:


> The only "souping" up they did was to modify the supercharger drive in order to take the increased mechanical load on the supercharger drive shaft.



Is that "souping up", or making production modifications to improve reliability?


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## Schweik (Jan 11, 2022)

Shortround6 said:


> I would note that the Russians had a strange incentive plan for P-40 pilots.
> If the unit did well in combat (and if they lived) they got to trade in their P-40s for Yaks or La-5s or P-39s.
> If they did not distinguish themselves in combat (and kept the P-40s running  ) they just got some replacement P-40s.



I would say that is a mischaracterization - if the *Unit *did well it became a Guards unit, and Guards units eventually got newer and better planes. In many cases that did mean a Yak, La-5 or P-39 (which the Soviets considered better) and as I mentioned before. In some cases it meant going from Tomahawk to Kittyhawk variants.

This was also, incidentally, the same 'incentive plan' for all Soviet guards units, including infantry and armor units. Guards units got the best available kit (and more food, ammunition, and everything else). That was their ruthless Malthusian system at work.

That is similar to what you wrote, but to me it's not quite the same thing.

As I mentioned a couple of times, the Kittyhawk, especially the P-40K, was an effective ride for quite a few Soviet pilots. For example Nikolai Fedorovitch Kuznetsov seen here celebrating after his 20th air victory, in front of his P-40K5 (you can see the tail fin just above his number 23)_. _







Kuznetsov was an ace several times over, (credited with 21 solo and 12 group victories) and twice HSU. He initially flew the I-16 and Hurricane, but scored all but one of his first 16 solo victories in the Kittyhawk before transferring to the P-39.

There is a bio about him here Kuznetsov Nikolai Fedorovich, photo, biography

Overall, the Soviets liked the P-40, but they never _loved_ it like they did the P-39. For them it was a middling aircraft, and they definitely thought a Yak 9 or La 5FN was better, as it undoubtedly was for their purposes. They also didn't think much of the P-47 or the Spit V for that matter.

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## pbehn (Jan 11, 2022)

wuzak said:


> Is that "souping up", or making production modifications to improve reliability?


I used the word to describe non standard machines presented or reported as typical of production. Things like removing heavy items and filling painting and polishing.


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## wuzak (Jan 11, 2022)

pbehn said:


> I used the word to describe non standard machines presented or reported as typical of production. Things like removing heavy items and filling painting and polishing.



But others have used it to describe production upgrades.


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## Thumpalumpacus (Jan 11, 2022)

Schweik said:


> Overall, the Soviets liked the P-40, but they never _loved_ it like they did the P-39.



Probably because the -40 didn't have nose armor.


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## pbehn (Jan 11, 2022)

wuzak said:


> But others have used it to describe production upgrades.


Thread drift. The Merlin (and all other) was improved throughout its life, but to me all engines issued for production Aircraft were production engines and were safe to use within the stated values given by RR (and Packard). Whatever was done in experimental programmes is another issue because they wouldnt be quoted in a test on a delivered production machine.

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## wuzak (Jan 11, 2022)

pbehn said:


> Thread drift. The Merlin (and all other) was improved throughout its life, but to me all engines issued for production Aircraft were production engines and were safe to use within the stated values given by RR (and Packard). Whatever was done in experimental programmes is another issue because they wouldnt be quoted in a test on a delivered production machine.



I should say that I agree with you regarding the term "souped up".

There may have been one or two companies that resorted to "souping up" their aircraft for factory testing in order to meet promises/get sales. I think one of those made groundhogs.

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## Admiral Beez (Jan 11, 2022)

Thumpalumpacus said:


> Probably because the -40 didn't have nose armor.


Nor a big cannon in the nose.


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## BlackSheep (Jan 11, 2022)

SaparotRob said:


> I'd trade my wife for a P-40 any day. I'll even throw in $20.


How many guns does she come with?

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## SaparotRob (Jan 11, 2022)

How many ya' want?

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## drgondog (Jan 12, 2022)

Schweik said:


> Thank God that German was working for us!


Edgar Schmued was a great design engineer and project manager - but Dutch Kindelberger (and otherd like Paul Ruud) were the genius behind the production methods and kindness. Kindelberger and Atwood were also fine engineers - both key at Douglas for the DC-3 before going to NAA.

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## Schweik (Jan 12, 2022)

Thumpalumpacus said:


> Probably because the -40 didn't have nose armor.



I think there are several reasons the Soviets liked the P-39 so much, but the most important IMO were - 

The P-39 was more like a Soviet fighter (relatively small, low drag, short range).
It's main flaws ('twitchiness' and potential for a flat spin) were not as unfamiliar to them (I-16, LaGG-3 and MiG-3 had the same problems). So Soviet pilots could handle them.
It was faster than other Lend-Lease fighters and had good climb (at low altitude).
It had the nose armament (they almost always removed the wing guns) and they apparently did like the big gun.
They did a 3 month workup on it before the brought it into combat, working out maintenance issues and tactics.

By the time you get to the later models, the P-39 was basically a Soviet fighter. I think they got most of them. The P-63 was actually built with direct input from two Soviet officers.

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## Thumpalumpacus (Jan 12, 2022)

Schweik said:


> I think there are several reasons the Soviets liked the P-39 so much, but the most important IMO were -
> 
> The P-39 was more like a Soviet fighter (relatively small, low drag, short range).
> It's main flaws ('twitchiness' and potential for a flat spin) were not as unfamiliar to them (I-16, LaGG-3 and MiG-3 had the same problems). So Soviet pilots could handle them.
> ...

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## Schweik (Jan 12, 2022)

Thumpalumpacus said:


>




Hahah sorry yeah I kinda figured but wasn't sure... I'm not up on all the inside jokes around here...

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## Thumpalumpacus (Jan 12, 2022)

Schweik said:


> Hahah sorry yeah I kinda figured but wasn't sure... I'm not up on all the inside jokes around here...



It's all good, brotha. I still appreciate you posting that info, though I'd already learnt it from the Thread That Shall Not Be Named®.

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## Schweik (Jan 12, 2022)

Yeah I get it. We all have tendencies to beat a dead horse sometimes. Some more than others... 

For as stupid as that thread and several others got, the P-39 is a bit of a baffling mystery, related to some others of a similar nature; chiefly why did some types do so much better in one place than others. I don't think it's as simple as 'the Soviets just lied about everything'.

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## FLYBOYJ (Jan 12, 2022)

Schweik said:


> I think there are several reasons the Soviets liked the P-39 so much, but the most important IMO were -
> 
> The P-39 was more like a Soviet fighter (relatively small, low drag, short range).
> It's main flaws ('twitchiness' and potential for a flat spin) were not as unfamiliar to them (I-16, LaGG-3 and MiG-3 had the same problems). So Soviet pilots could handle them.


The I-16 was very light on the controls and had good aileron control. To say all 3 had a potential for a "flat spin" is a broad brush because all 3 had different stability issues and different control responses. Reading the book "Some Still Live" by Frank Tinker, an American mercenary pilots who flew the I-16 during the Spanish Civil War, he seemed to like the aircraft, spoke well about it's guns and said it was faster, more maneuverable and a better climber than the early Bf109s used by the Condor Legion.

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## Thumpalumpacus (Jan 12, 2022)

Schweik said:


> Yeah I get it. We all have tendencies to beat a dead horse sometimes. Some more than others...
> 
> For as stupid as that thread and several others got, the P-39 is a bit of a baffling mystery, related to some others of a similar nature; chiefly why did some types do so much better in one place than others. I don't think it's as simple as 'the Soviets just lied about everything'.



I think it's a matter of it working for them because their circumstances (low-altitude, short-range combat environment) minimized the -39's weaknesses. I think also the pilots themselves matter. In SWPA, P-39 pilots who tried to turn-fight a Zero or Ki-43 was usually not long for this earth. You fly the airplane to its strengths, because you know your enemy is going to be trying to expose and exploit your plane's weaknesses. 

The Eastern Front's aerial combat regime naturally masked two of the P-39's flaws (anemic performance at altitude, and range). Gritty Soviet pilots did the rest.

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## Schweik (Jan 12, 2022)

FLYBOYJ said:


> The I-16 was very light on the controls and had good aileron control. To say all 3 had a potential for a "flat spin" is a broad brush because all 3 had different stability issues and different control responses. Reading the book "Some Still Live" by Frank Tinker, an American mercenary pilots who flew the I-16 during the Spanish Civil War, he seemed to like the aircraft, spoke well about it's guns and said it was faster, more maneuverable and a better climber than the early Bf109s used by the Condor Legion.



I think the I-16 was in many ways an excellent fighter. I agree it had superb aileron control, in fact I gather it had a very high roll rate. That sometimes goes along with a certain amount of instability - as does a short fuselage. My comment about the proclivity for spin is based on the comments by several Soviet pilots, including in that interview with Golodnikov. 

I-16, especially once they put 20mm cannon on it, always had potential as a fighter, and it certainly did well in the Spanish Civil War and in Manchuria, it just fell behind in terms of raw speed and power as the war progressed. I don't think any version of I-16 was really competitive with a Bf 109F. The degree of control problems varied with different engines and configurations of guns and other equipment which varied quite a bit with different sub-variants over time. The Soviets liked the I-16 for a long time, but it was regarded as a 'twitchy' plane, and became obsolete during the first year of the war, if it wasn't already.

For that matter, I think the LaGG-3 (eventually) was a good, or at least decent fighter design. They had enormous production quality problems with it, and it was initially underpowered, but both issues also affected the early Yak-1 and other types. By the time they had a 'good' LaGG-3 variant (sometimes in modern times called the -66 variant, though probably some earlier blocks as well) the La-5 was already out and was probably better all around for most purposes.

Being a bit 'twitchy' doesn't make a fighter bad, it's just a characteristic. The P-39 was definitely 'twitchy', the P-40 was also a little bit especially at higher speeds. The Hurricane was much more stable but it didn't do so well in Soviet use (though it still played an important role for them in the early days, because they were so short on decent planes, and it was certainly faster than an I-153).

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## Schweik (Jan 12, 2022)

Thumpalumpacus said:


> I think it's a matter of it working for them because their circumstances (low-altitude, short-range combat environment) minimized the -39's weaknesses. I think also the pilots themselves matter. In SWPA, P-39 pilots who tried to turn-fight a Zero or Ki-43 was usually not long for this earth. You fly the airplane to its strengths, because you know your enemy is going to be trying to expose and exploit your plane's weaknesses.
> 
> The Eastern Front's aerial combat regime naturally masked two of the P-39's flaws (anemic performance at altitude, and range). Gritty Soviet pilots did the rest.



I agree with a lot of that, and the three month workup the Soviets did with the plane meant they had a head start in understanding it's strengths and weaknesses. Allied units in the early Pacific fighting were often rushed into battle with little to no training on type, I know that was the case with almost all the early P-40 squadrons for sure. But I also suspect there may have been some other issues, like field stripping, and also maybe something to do with the temperature. I gather some aircraft did better in cold or cooler temperature vs. tropical and humid. Which obviously affects air density.

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## Schweik (Jan 12, 2022)

Maybe someone with some better physics and / or engineering knowledge than I can chime in on that. I think this may be relevant for the Buffalo as well.


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## GrauGeist (Jan 12, 2022)

Schweik said:


> Maybe someone with some better physics and / or engineering knowledge than I can chime in on that. I think this may be relevant for the Buffalo as well.


Check out "Density Altitude".

I know this is Wiki, but it gives a good overview:








Density altitude - Wikipedia







en.m.wikipedia.org

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## Clayton Magnet (Jan 12, 2022)

Schweik said:


> I don't think any version of I-16 was really competitive with a Bf 109F


Nor the Bf 109E. The I-16 may have had some advantages over the Jumo powered Messerschmitt's over Spain, but was thoroughly outclassed by the E-3's and E-7's that it met in the summer of 1941.

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## Schweik (Jan 12, 2022)

Well the I-16 was certainly weaker - especially without radios, but they did occasionally seem to get some victories. There were several I-16 Aces in Russia and I don't think they were all made up (YMMV).

Even if it's say, 20% -30% as good, that can still be of some value and (with the right tactics) offer some challenge.


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## Schweik (Jan 12, 2022)

GrauGeist said:


> Check out "Density Altitude".
> 
> I know this is Wiki, but it gives a good overview:
> 
> ...



Thanks. A lot of that is over my head as I lack the math and engineering chops, but this sentence seems to help:

_"In hot and humid conditions, the density altitude at a particular location may be significantly higher than the true altitude."_

So if I read that correctly, if it's say 100 F and 95% humidity in Guadalcanal, that may mean that performance at Sea Level is equivalent to some number (thousands?) of feet higher. Which might explain P-39 having some trouble.

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## FLYBOYJ (Jan 12, 2022)

Schweik said:


> So if I read that correctly, if it's say 100 F and 95% humidity in Guadalcanal, that may mean that performance at Sea Level is equivalent to some number (thousands?) of feet higher. Which might explain P-39 having some trouble.


It's called density altitude and it effects all aircraft.

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## Schweik (Jan 12, 2022)

So how much of a difference (in terms of thousands of feet) would 100F and 95% humidity make?


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## Clayton Magnet (Jan 12, 2022)

Schweik said:


> Thanks. A lot of that is over my head as I lack the math and engineering chops


Think of density altitude as the altitude that the aircraft _FEELS _its at. It may be operating at sea level, but with a density altitude of 3000' for example

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## Schweik (Jan 12, 2022)

Right i get that, I was wondering what the actual ratios might be, like for the example I gave (100 F and 95 humidity) is it that much? More or less?


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## FLYBOYJ (Jan 12, 2022)

Schweik said:


> So how much of a difference (in terms of thousands of feet) would 100F and 95% humidity make?


A lot! Most performance charts start at a baseline, sea level 59F 29.92 air pressure. High temperatures and humidity will make the aircraft perform at sea level as if it was at a higher altitude. Here is a simple calculator. At 100F and 95% humidity your plane will perform as if it was at almost 3,000' MSL






E6BX | Aviation Calculators


E6B, NavLog Calculator, Weather Reports, METAR, TAF, Wind Components, Instrument Simulator, Weight and Balance, Pressure Altitude, Density Altitude, True Air Speed, and a lot more.




e6bx.com

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## Simon Thomas (Jan 12, 2022)

...


Schweik said:


> So how much of a difference (in terms of thousands of feet) would 100F and 95% humidity make?


If you were at sea level, those conditions are equivalent to 3365 ft.


Density Altitude Calculator - English/Metric, Relative Humidity

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## Clayton Magnet (Jan 12, 2022)

Schweik said:


> Right i get that, I was wondering what the actual ratios might be, like for the example I gave (100 F and 95 humidity) is it that much? More or less?


Assuming a sea level field elevation and an altimeter setting of 29.92, the density altitude at 100 degrees F would be just under 3000'

Edit: Sorry, I missed the other replies. Disregard

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## Schweik (Jan 12, 2022)

Ok thanks! Very helpful and interesting. So that means in the SW Pacific the critical altitude for a P-39D drops from around 13,000 to about 10,000 ft. Of course, early P-40s also have the same problem. F4F has much better altitude performance than either army type, still producing ~ 1,000 hp at 20,000 ft (maybe 17,000 in these weather conditions, or does that still apply once you are up in the colder air?). This maybe helps explain why F4F was still so important despite seeming to have much lower top speed. It's still in the game for another 10,000 ft.

With a bit smaller wings, P-39 may not be as stable as some other types in the (effectively) thinner / hot air?


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## Thumpalumpacus (Jan 12, 2022)

The warmer the air, the less the density. The less the density, the less lift can be developed at a given speed. This is a variable that will affect all planes operating in the same airspace in a roughly equal manner. This is also affected by altitude. A warm day in Denver requires a longer takeoff roll than a cold day in Boston.

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## Schweik (Jan 12, 2022)

Thumpalumpacus said:


> The warmer the air, the less the density. The less the density, the less lift can be developed at a given speed. This is a variable that will affect all planes operating in the same airspace in a roughly equal manner. This is also affected by altitude. A warm day in Denver requires a longer takeoff roll than a cold day in Boston.



I get that, my observation was, _maybe_ aircraft with a little bit higher wing-loading and a shorter wingspan might have a bit more trouble in thinner air. Not saying that's it so, just speculating.


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## FLYBOYJ (Jan 12, 2022)

Schweik said:


> With a bit smaller wings, P-39 may not be as stable as some other types in the (effectively) thinner / hot air?


A little be more complicated than that - you have to consider the wing design, camber, etc. I'm Showing the P-39 had a NACA 0015 wing at the root, a NACA 23009 at the tip, someone like Bill or GregP could probably do the math and tell you how that wing will perform in thinner air

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## FLYBOYJ (Jan 12, 2022)

Schweik said:


> I get that, my observation was, _maybe_ aircraft with a little bit higher wing-loading and a shorter wingspan might have a bit more trouble in thinner air. Not saying that's it so, just speculating.


Living and flying around the Denver metro area, I could attest to that. The airport where I fly out of is about 5600' MSL, I've seen days when the density altitude was close to 10,000'

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## Schweik (Jan 12, 2022)

Is there an instrument on the aircraft to measure that or do calculate it based on temperature, humidity and barometric pressure using a tool like you linked upthread?


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## FLYBOYJ (Jan 12, 2022)

Schweik said:


> Is there an instrument on the aircraft to measure that or do calculate it based on temperature, humidity and barometric pressure using a tool like you linked upthread?


It’s calculated. You start with the chart previously posted and then you use performance charts specific to the aircraft

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## BiffF15 (Jan 12, 2022)

Schweik said:


> Is there an instrument on the aircraft to measure that or do calculate it based on temperature, humidity and barometric pressure using a tool like you linked upthread?


Instruments on airplanes are funny things. In pilot training we had to do a TOLD (Take Off and Landing Data) problem every flight in the T-38 to figure out all your speeds (max abort, se t/o) plus some others I've no doubt dumped from memory. However, while sitting on the ramp at Roswell (home of the little green men and a instrument approach called the widow maker) my IP told me to dial 2992 into the altimeter (kollsman window) and it will show you what altitude the aircraft "thinks" it's at or, more accurately the pressure altitude of the airfield. Get the temp, do your TOLD, go fly. It's also useful if you think the ATIS (Airport Terminal Information Service) is inaccurate (usually updated once an hour unless conditions change enough). The altimeter can tell you more than just your altitude. In the OV-10 we had a thermometer that stuck out of the canopy, and we would do our TOLD problem just prior to take off. Not sure why, we took off below engine out take off speed(V2) (plane didn't have enough power to get to V2 on the ground), and in the event of an engine out missed it probably didn't have enough power to go around. If you touched down you would not get airborne again on one engine. That airplane (OV-10A) was a performance dud.

I started flying the Eagle in late 91. We didn't use TOLD data. The IPs told us if your nose wheel was off the runway go, if it wasn't you could abort (with one or less bags of gas). If you had 3 bags of gas it was full A/B and use around 190 as your single engine take off speed (SETOS). Fast forward about 10 years and we have two accidents and lack of TOLD data was supposedly a contributing factor. First accident was an ex F-18 guy at New Orleans who brought the gear up and settled back on the runway. That only happens if you lift off slow. Duh. Second was an accident at Nellis where the A/B nozzle gauges were backwards. So the left shows blown out, and per the checklist you pull the left out of burner and continue the take off if able. He tried, and went off the end of the runway hauling ass, punched out and got banged up pretty badly. Come to find out his nozzles where cross wired, and he pulled the good engine out of AB and tried to continue the take off in a heavy jet, high pressure altitude, with neither in AB. TOLD may have helped him make a timely decision to reject.

I got off the beaten path a bit, but just some context on why pressure altitude is important knowledge to have.

Cheers,
Biff

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## FLYBOYJ (Jan 12, 2022)

Hey Biff - something funny. Up until a few years ago the old T-41s operated at the Academy had no TOLD data above 10,000’. IPs used to love to fly to Leadville on their “proficiency“ flights. A sharp IG inspector caught this.

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## Schweik (Jan 12, 2022)

It's one of those things that after near 40 years of reading about airplanes practically every day, I never really understood this until today. It's quite interesting and I suspect it does help explain why some types did better in tropical environments and some in cold. 

When I first read that description of takeoff etc., I misread and thought you were describing the T-38 as a 'performance dud'. 

Does the TOLD etc. have the same relevance once you are up high and it's colder ?


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## Clayton Magnet (Jan 12, 2022)

Schweik said:


> why some types did better in tropical environments and some in cold.


EVERY aircraft does better in cold, assuming not too cold. Cold dry air is best for performance, no matter what aircraft you are flying

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## Schweik (Jan 12, 2022)

Clayton Magnet said:


> EVERY aircraft does better in cold, assuming not too cold. Cold dry air is best for performance, no matter what aircraft you are flying



I get that, but if you have a higher wing-loading and maybe a bit of a propensity to spin, might this not be a bit more of a problem in tropical conditions?

I.e. I am thinking a Hurricane might actually be better than say, an I-16 in say, Egypt in August, while the reverse may be true in December in Leningrad.


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## Schweik (Jan 12, 2022)

In theory (effectively) thinner air at lower altitude might make for higher speeds but a lot of WW2 aircraft seemed to have problems with cooling in high temperature environments.


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## Shortround6 (Jan 12, 2022)

As a very rough estimate the plane that has a higher loading (higher wing loading and higher power loading) will have more "trouble" than the plane with a lower loading. 

You are dealing with a "double whammy". The engine is going to make less power at the same manifold pressure and the wing is going to generate less lift for the same airspeed. 

I am not a pilot so I may be way off on this. 

Say plane A takes off at 80mph and plane B takes off at 100mph on a standard day (59 degrees/standard pressure) and with the temperature, humidity and barometric of the time of day at take off we calculate that we are going to need 10% more speed (lift?) to get the plane up to take-off speed. Plane A now needs 88mph and plane B needs 110mph, small advantage to Plane A *BUT *both planes are going to accelerate slower due to lower engine power (and the props may have have less bite) so plane B is going to need a longer distance to take off. 
The Climb performance is going to be off as plane B needs more power just to stay in the air (Higher stalling speed).

You not only need the calculator for the air conditions you need the manuals or charts for each each plane because they are all not at the same, Hot and High will be higher for each plane but not always the same.

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## Shortround6 (Jan 12, 2022)

Schweik said:


> In theory (effectively) thinner air at lower altitude might make for higher speeds but a lot of WW2 aircraft seemed to have problems with cooling in high temperature environments.



once you are dealing with high speeds you have more variables to come out and play with

Drag goes up with the cube of speed.
Your Lift goes up with the square of the speed.
The engine power (as opposed to propeller efficiency) is a combination of air density (not much change in speed) and the RAM effect of the intake and the pressure ratio of the supercharger on WW II airplanes.
Some of this is somewhat academic.

If your plane will only fly at 330mph true instead of 345mph true at 10,000ft due to hot temperatures you aren't going to know it. You are going to be looking at IAS for airspeed and the airspeed indicator is reading the existing air pressure (density). If the enemy airplane is also by 10-15mph from it's "book" figures it is going to take a long tail chase to to figure out the speed difference.

The speed/climb differences at 80-150mph when taking-off and landing are what can kill you every time you take-off and land.







I have no idea why they figured out the chart this way instead of using 59 Degrees (standard day) but the Army Charts are measured from O degrees C and 32 degrees F. (maybe they figure you know the difference between your boots sliding on ice or splashing through a puddle?). But at just about 92 degrees for the P-38 your take off distance will be 20% higher than the chart shows. North Africa can be worse.
Note that they are only figuring a 10% increase in time to climb compared to the 20% increase in take-off run.

Edit: Screwed up the math, 32 degrees F from 92 degrees is 60 degrees so we need a 30% increase in take-off run and not 20%. 
Change in temperature of 60 degrees F is worth about 2,000lbs of take off weight to the P-38 on a clean, dry runway.

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## PAT303 (Jan 12, 2022)

pbehn said:


> The RAF and Supermarine conducted tests for all sorts of reasons, like producing a Spitfire with all flush rivets, covering them with split peas and progressively removing them to see how speed was affected.


Spitfires were extensively tested by the RAE in regards to the who what and when and their effects speed, aerials, guns, blisters, ejection ports, rear view mirrors, exhaust types, panel fit and over paint condition and fit and finish where all tested and they had no trouble getting a 20-30mph increase in speed from Mk1's through to MkIX's by incorporating all the above.

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## BiffF15 (Jan 12, 2022)

Shortround6 said:


> once you are dealing with high speeds you have more variables to come out and play with
> 
> Drag goes up with the cube of speed.
> Your Lift goes up with the square of the speed.
> ...


Shortround6,

My guess on why the charts start at 0c for simplicity. Notice there are no corrections for below 0c (Assumption none needed. I fly the A319/320 and some of our charts bottom out at -5c). Makes for simpler math for your airmen.

Cheers,
Biff

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## Thumpalumpacus (Jan 12, 2022)

Schweik said:


> I get that, my observation was, _maybe_ aircraft with a little bit higher wing-loading and a shorter wingspan might have a bit more trouble in thinner air. Not saying that's it so, just speculating.



I think it's sound thinking. A smaller wing develops less lift anyway, and it stands to reason that in less-dense air a smaller wing carrying the same weight will have more trouble.

Mine wasn't a correction to you, simply an added thought.


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## pbehn (Jan 12, 2022)

PAT303 said:


> Spitfires were extensively tested by the RAE in regards to the who what and when and their effects speed, aerials, guns, blisters, ejection ports, rear view mirrors, exhaust types, panel fit and over paint condition and fit and finish where all tested and they had no trouble getting a 20-30mph increase in speed from Mk1's through to MkIX's by incorporating all the above.


I know, but a production machine was tested in the as produced condition (where this discussion started). Things like aerials cannon blisters etc would be noted.


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## BiffF15 (Jan 12, 2022)

Schweik said:


> It's one of those things that after near 40 years of reading about airplanes practically every day, I never really understood this until today. It's quite interesting and I suspect it does help explain why some types did better in tropical environments and some in cold.
> 
> When I first read that description of takeoff etc., I misread and thought you were describing the T-38 as a 'performance dud'.
> 
> Does the TOLD etc. have the same relevance once you are up high and it's colder ?


Schweik,

TOLD has relevance regardless of your altitude and temp. It's done to operate your airplane safely and efficiently. At my airline under normal conditions I pull up the data for the runway I think we will get, as well as a back up if I think there is a chance of a switch (it happens regularly). If my first runway is 15k long (think Denver) and the second is 12k, I should be able to use the same performance data (what my airline calls TOLD) but I can't. Our data is optimized around each runway (obstacles in the departure path not always visible), engine wear (we do reduced power take offs which is less stress / wear on the engines), take off speed (higher is better from a safety perspective should you lose an engine - you carry more energy airborne, getting to engine out acceleration altitude sooner + shorter distance from T/O = getting to clean maneuvering speed quicker / flaps up speed). As well as tire speed. All is balanced and done by the master computer at company HQ and accessed via a system called ACARS. Think limited texting with the ability to print out what we receive. Also runway 8 at Denver is downhill. Most airliners, and the F-15 operated with a 10 knot tailwind max (wouldn't mess with your TOLD enough to warrant a change). The A320 can go with a 15 kt tailwind. F-16s go with a 0 kt tailwind.

Prior to landing I pull up data that shows how long our landing roll should be for a given runway, and it covers various braking strengths, as well as runway slickness factors and how heavy we can be and still do a safe go around.

I fixed the above dud comment to include the Mighty Bronco.

In the Eagle, with a single centerline or no external tank, we could easily take off with one engine. While I haven't done that, I have heard of guys who did (by his wingman). TOLD is very important in airliners / big planes, and is of less relevance in a small afterburner equipped plane (you accelerate so fast it's almost "what's the point".

Cheers,
Biff

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## BiffF15 (Jan 12, 2022)

Thumpalumpacus said:


> I think it's sound thinking. A smaller wing develops less lift anyway, and it stands to reason that in less-dense air a smaller wing carrying the same weight will have more trouble.
> 
> Mine wasn't a correction to you, simply an added thought.


Here is another way to thinking about it. The plane flies like it's at the altitude it thinks its at. If you take off from hot, it flies like it's higher than it is (it wheezes sooner). High altitude fields make this worse as your take off performance is even more affected. Take off from cold, the plane flies at the altitude it thinks its at, which is lower than it really is (has more get up and go). High altitude fields reduce this some. 

If you didn't have an altimeter / airspeed indiciator but knew how your plane flies / what power it makes and speed that gives. Then you would set 50" of manifold pressure and would expect to see 300 mph at 10k (this is an example). In reality, using those power figures and altitude guesstimates you see less than 300 mph which would lead you to believe you are higher than you guessed. In reality you are at 10k and it's hotter than standard. The plane doesn't know, it makes the power and speed it can given the altitude and the temp.

Cheers,
Biff

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## Thumpalumpacus (Jan 12, 2022)

BiffF15 said:


> Here is another way to thinking about it. The plane flies like it's at the altitude it thinks its at. If you take off from hot, it flies like it's higher than it is (it wheezes sooner). High altitude fields make this worse as your take off performance is even more affected. Take off from cold, the plane flies at the altitude it thinks its at, which is lower than it really is (has more get up and go). High altitude fields reduce this some.
> 
> If you didn't have an altimeter / airspeed indiciator but knew how your plane flies / what power it makes and speed that gives. Then you would set 50" of manifold pressure and would expect to see 300 mph at 10k (this is an example). In reality, using those power figures and altitude guesstimates you see less than 300 mph which would lead you to believe you are higher than you guessed. In reality you are at 10k and it's hotter than standard. The plane doesn't know, it makes the power and speed it can given the altitude and the temp.
> 
> ...



Right, that's why we see more accidents in African highland airports, because while the plane knows what it needs to fly, the pilot still has ingrained patterns which can cause problems.

I guess that "listen to your airplane" is probably some good advice here.

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## BiffF15 (Jan 12, 2022)

Thumpalumpacus said:


> Right, that's why we see more accidents in African highland airports, because while the plane knows what it needs to fly, the pilot still has ingrained patterns which can cause problems.
> 
> I guess that "listen to your airplane" is probably some good advice here.


My guess in third world countries you will see more accidents due to poor training / decision making.

Here is an example. I've been briefed but am unable to share details.


There is a reason we have the safety stats we do. Be very very careful the further you get away from North America or Europe.

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## Simon Thomas (Jan 12, 2022)

Easy on. Australian & New Zealand are a long, long way from North America and Europe.

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## BiffF15 (Jan 12, 2022)

Simon Thomas said:


> Easy on. Australian & New Zealand are a long, long way from North America and Europe.


Yes, I stand corrected! Sorry about that, no snub intended! I think Qantas has the hands down best safety record.

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## pbehn (Jan 12, 2022)

I tried to avoid places where the pilot got a round of applause on landing, like Saudi Arabia internal flights.

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## Thumpalumpacus (Jan 12, 2022)

BiffF15 said:


> My guess in third world countries you will see more accidents due to poor training / decision making.
> 
> Here is an example. I've been briefed but am unable to share details.
> 
> ...




No doubt lower training standards are a factor. I was just saying that planes don't like to fly so much when the air is hot and thin.

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## wuzak (Jan 12, 2022)

Shortround6 said:


> Drag goes up with the cube of speed.
> Your Lift goes up with the square of the speed.



Does not drag go up with the square of speed also?

Power required goes up with cube of speed.


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## GrauGeist (Jan 12, 2022)

Then perhaps compare the accident rate for the P-38s of the 12AF that operated in the UK and then sent to North Africa in '42.

Two entirely different climates.

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## Thumpalumpacus (Jan 12, 2022)

GrauGeist said:


> Then perhaps compare the accident rate for the P-38s of the 12AF that operated in the UK and then sent to North Africa in '42.
> 
> Two entirely different climates.



From what I've read, the -38 acclimated to the Med much better than it did in Northwestern Europe. Is this accurate? The reasons I've read refer to engine cooling and altitude flight. If you've got any insights I'd love to hear them.

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## Shortround6 (Jan 12, 2022)

wuzak said:


> Does not drag go up with the square of speed also?
> 
> Power required goes up with cube of speed.


you are correct.

But when you are accelerating down the runway at over 100mph and the wing is NOT lifting (less lift) and the engine/s are not supplying enough power and the embankment at the end of the runway is getting much closer are we talking about the required speed needed (power) to clear the runway or drag?

Drag does go up with square of the speed as an instantaneous force. As in "at 100mph the airframe will exbibit XXX lbs of drag."


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## Greg Boeser (Jan 12, 2022)

Thumpalumpacus said:


> I think it's sound thinking. A smaller wing develops less lift anyway, and it stands to reason that in less-dense air a smaller wing carrying the same weight will have more trouble.
> 
> Mine wasn't a correction to you, simply an added thought.


This severely hampered B-26 operations in the South Pacific. A Navy report from mid 1943 rated the early B-26B with the R 2800-5 engines as having a combat ceiling of 12000' and a max bomb load of 2000 lbs. Take off run was longer than a fully loaded B-17.

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## Shortround6 (Jan 12, 2022)

Thumpalumpacus said:


> From what I've read, the -38 acclimated to the Med much better than it did in Northwestern Europe. Is this accurate? The reasons I've read refer to engine cooling and altitude flight. If you've got any insights I'd love to hear them.


The problem was that the P-38s used in the Med used different inter-coolers and quite possible different model superchargers (and possible different turbo controls ) over Europe in 1944 than they were using in early/ mid 1943.

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## Thumpalumpacus (Jan 12, 2022)

Shortround6 said:


> The problem was that the P-38s used in the Med used different inter-coolers and quite possible different model superchargers (and possible different turbo controls ) over Europe in 1944 than they were using in early/ mid 1943.



Were the engines running too cold over ETO? That's the implication of what I've read. I know it's a big ask but it's something I'm curious about. If you or someone else could say a bit more about this I'd be grateful.


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## nuuumannn (Jan 12, 2022)

BiffF15 said:


> I fixed the above dud comment to include the Mighty Bronco.



You flew the Bronco, Biff? Awesome! If ever I was in a position to operate an aircraft for that go-anywhere personal transport it'd be a Bronco.


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## GrauGeist (Jan 12, 2022)

Shortround6 said:


> The problem was that the P-38s used in the Med used different inter-coolers and quite possible different model superchargers (and possible different turbo controls ) over Europe in 1944 than they were using in early/ mid 1943.


I suggested comparing the operational records of the 12AF P-38s groups that were first operating in the UK before being transferred to North Africa in 1942, because it would have the same aircraft piloted by the same guys.

If I remember right, some of the P-38s groups also operated in Iceland for a time before continuing on to the UK, too.

All my stuff is still in storage, so I'm not able to check any figures.

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## BiffF15 (Jan 12, 2022)

nuuumannn said:


> You flew the Bronco, Biff? Awesome! If ever I was in a position to operate an aircraft for that go-anywhere personal transport it'd be a Bronco.


Yes I did. Replacement Training Unit (RTU) at Davis-Monthan AFB, AZ in late summer 1989. Shaw AFB from 1990-1991 (2 years in the Bronco including the school house). The Bronco went away and half the squadron transitioned to the OA-10, the rest went out into the USAF fighter world). I have about 395 hours in it, 2 ship flight lead, and got to fly my jet down to Columbia for their AF. We departed Shaw AFB, stopped at Homestead AFB for the night, Kit and Tinas in the Caicos Islands night 2, Cayman Islands night 3, Howard AFB night 4, then down to Columbia (had lunch) and returned to Howard for night 5. RTB'd the next day. We were paid 1100 in per diem, and I only spent 1200 (yeehaw!). And we followed a C-130 with it's flaps down (so we could keep up). We also had "man portable" GPS in the back seat of the lead Bronco. It weighted about 25lbs, and the keypad was at the end of a 4 foot phone cord (curly) and displayed left / right and lat longs (for use incase we became separated). In the big scheme of things the way to the USAF operated it was pretty thin performance wise. It did have good legs, burned about 600lbs / hr (easy math) and could land about anywhere (I took one in and out of a 3300' strip).

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## Schweik (Jan 12, 2022)

BiffF15 said:


> My guess in third world countries you will see more accidents due to poor training / decision making.
> 
> Here is an example. I've been briefed but am unable to share details.
> 
> ...




Or they they are sold a new model with some dodgy software and the vendor neglects to warn anybody...

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## Schweik (Jan 12, 2022)

Shortround6 said:


> you are correct.
> 
> But when you are accelerating down the runway at over 100mph and the wing is NOT lifting (less lift) and the engine/s are not supplying enough power and the embankment at the end of the runway is getting much closer are we talking about the required speed needed (power) to clear the runway or drag?
> 
> Drag does go up with square of the speed as an instantaneous force. As in "at 100mph the airframe will exbibit XXX lbs of drag."



So I'm also wondering, conversely, an aircraft with a lot of lift, like lets say a Hurricane with a 40' wingspan and a think wing, is that going to maybe have a bit more drag, and possibly not as good of a roll rate in very cold conditions, say 10F? I ask because I often wondered why the Soviets were so dismissive of the Hurricane and it's "stately maneuvering" - on paper it looks better than an I-16 in many ways and probably an LaGG-3 too. 

Second question is, does the hot and humid weather (by contrast) mean that a plane with a lower wing loading (like a P-39) is going to have more problems than one with the lower wing loading (like an A6M) or are they just affected equally? In other words, would one type of aircraft be better suited to tropical conditions?


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## BiffF15 (Jan 12, 2022)

Schweik said:


> Or they they are sold a new model with some dodgy software and the vendor neglects to warn anybody...


I don't think so. It's been in production since the 80s. When a plane has a serious incident, there is a quick look (don't forget the black boxes were pulled) and the manufacturer along with several operators determine if something is wrong with the plane. If it's plane problem ALL the users are notified ASAP and the pilots get bulletins if the plane isn't grounded (Boeing Max). There were no groundings of planes nor bulletins. Remember that in the future, it's a show of cards if you understand what it means. 

I have plumbed the DC8, DC10 and 727. I have flown T37, T38, AT38B, OV10A, F15A-D, A319/320 and 757/767. I have somewhere around 9k hours of flying time in other than light a/c. It is hands down the SAFEST plane I have ever flown. It is almost idiot proof. Have an emergency, the checklist comes up in the glass (you can see it in the video). If you have something you need to do, it's in blue letters (also seen in the video). We call them, Blue to Do's. If you have multiple emergencies, it brings up the checklists as appropriate. It almost won't let you hurt it. Overspeed, got you covered, over G, over bank, stall, throttles back when they should be up, yep, that too. The only thing you have to put up with is it will call you a retard at least twice every leg (French for bring those levers back to idle). When the final gets released I think you will be shocked.

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## Schweik (Jan 12, 2022)

I was referring to the two crashes in Ethiopia and Malaysia with the 737 MAX 8, apparently the pilots were not notified of the potential issue with the software and the need to shut it off in some scenarios. Apparently Boeing had references to the new software removed from the flight manual.

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## BiffF15 (Jan 12, 2022)

Schweik said:


> I was referring to the two crashes in Ethiopia and Malaysia with the 737 MAX 8, apparently the pilots were not notified of the potential issue with the software and the need to shut it off in some scenarios. Apparently Boeing had references to the new software removed from the flight manual.


Yes, Boeing screwed the pooch on how they handled that. They are running into some serious quality control issues on the 787 (haven't delivered many in the past 8-12 months). The 767 tanker has had quality control, quality assurance, and hardware problems. The T-7 is way, way behind. The PW powered 777s should be airborne again in the next few months (the ones with the exploding engines). However, the 777x has problems of it's own. They have dug themselves a hole but think they will climb out of it.

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## BiffF15 (Jan 12, 2022)

Schweik said:


> I was referring to the two crashes in Ethiopia and Malaysia with the 737 MAX 8, apparently the pilots were not notified of the potential issue with the software and the need to shut it off in some scenarios. Apparently Boeing had references to the new software removed from the flight manual.


Also realize there were some pilot errors in both those accidents. In both they hit the ground in full power, which had been set on takeoff roll. The faster you go, the tougher it is to handle trim problems. Also, realize that each countries version of the FAA operate under different direction. One of those countries has had numerous accidents and at one time was not allowed to operate flights to the US. Each countries FAA has direction, sometimes it's to get to the bottom of things, other times it's to make sure someone doesn't look bad who maybe should. Are you aware of the hierarchy in Asian countries. The plane manufacturers was at fault, but in my opine not enough spotlight was shown on the crew, their backgrounds, sim performance, etc. Boeing won't say that airlines pilot sucked, since they want to continue selling them jets. Lots at play and not just what happened.

Think of it this way. If your car is pulling to the left hard at 30, are you going to speed up to make it worse? No. Trim works the same way, it's just the ability to get rid of the "pull" if it's functioning correctly.

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## Schweik (Jan 12, 2022)

I hope Boeing can sort it out. I wonder if they might be better off as a couple of different firms instead of one huge one. They do a lot of different things.


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## FLYBOYJ (Jan 12, 2022)

Schweik said:


> I hope Boeing can sort it out. I wonder if they might be better off as a couple of different firms instead of one huge one. They do a lot of different things.


Boeing IS made up of several different companies under one corporate umbrella. I worked for them brifely in 1990, Chis works for them in St. Lous


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## SaparotRob (Jan 12, 2022)

BiffF15 said:


> Yes, Boeing screwed the pooch on how they handled that. They are running into some serious quality control issues on the 787 (haven't delivered many in the past 8-12 months). The 767 tanker has had quality control, quality assurance, and hardware problems. The T-7 is way, way behind. The PW powered 777s should be airborne again in the next few months (the ones with the exploding engines). However, the 777x has problems of it's own. They have dug themselves a hole but think they will climb out of it.


I read/saw an article/YouTube about Boeing losing its way. The article implied that MACAIR execs somehow took over Boeing after the merger and a major corporate culture change occurred. This was a big factor in the 737 Max issues. 
I was wondering how to bring the topic up. Perhaps its own thread with a better title?


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## SaparotRob (Jan 12, 2022)

BTW. I find it hard to believe McDonnell Douglas would take any short cuts.

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## Schweik (Jan 12, 2022)

Anyway, getting back to the hot air and lift issues.... is this a reason to assume that some types might do better in different climates? (I mean prior to afterburners and jets with 50,000 lbs thrust)


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## FLYBOYJ (Jan 12, 2022)

SaparotRob said:


> I read/saw an article/YouTube about Boeing losing its way. The article implied that MACAIR execs somehow took over Boeing after the merger and a major corporate culture change occurred. This was a big factor in the 737 Max issues.
> I was wondering how to bring the topic up. Perhaps its own thread with a better title?


Actually it was the other way around. Boeing swallowed up MACAIR and systematically eliminated it's commercial division. The only holdover was the 717 and eventually that went away as it competed with the 737. Boeing made a lot of money when they started selling off the old factory in Long Beach. I knew many people who worked for McDonnel Douglas when they "merged" with Boeing, in their eyes it was like surrendering to your mortal enemy.

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## FLYBOYJ (Jan 12, 2022)

Schweik said:


> Anyway, getting back to the hot air and lift issues.... is this a reason to assume that some types might do better in different climates? (I mean prior to afterburners and jets with 50,000 lbs thrust)


For the most part. no. Again, in layman's terms, density altitude will make a given aircraft perform as it would at a higher altitude when it may be several thousand feet lower.


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## SaparotRob (Jan 12, 2022)

FLYBOYJ said:


> Actually it was the other way around. Boeing swallowed up MACAIR and systematically eliminated it's commercial division. The only holdover was the 717 and eventually that went away as it competed with the 737. Boeing made a lot of money when they started selling off the old factory in Long Beach. I knew many people who worked for McDonnel Douglas when they "merged" with Boeing, in their eyes it was like surrendering to your mortal enemy.


That's what was strange about the article. I know Boeing acquired McDonnell Douglas. I guess the piece implied some diabolical "5th column" cabal. 
Ok Schweik, back to you.


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## BiffF15 (Jan 13, 2022)

SaparotRob said:


> I read/saw an article/YouTube about Boeing losing its way. The article implied that MACAIR execs somehow took over Boeing after the merger and a major corporate culture change occurred. This was a big factor in the 737 Max issues.
> I was wondering how to bring the topic up. Perhaps its own thread with a better title?


I read an editorial in the back of Automobile magazine by a former big three CEO. He had been asked how VW could have a diesel gate type of event. His reply was very telling. He mentioned meeting the CEO of VW at an auto show. He said he complimented him (the VW CEO) on his panel gaps at all levels of cars. VW at the time was considered the benchmark of panel gaps (smaller gaps are better, and show a quality of manufacturing) on relatively inexpensive cars. He replied that was easy. He brought his guys in, told them they had three weeks to figure it out, or they were fired. People like to have jobs, it provides food, shelter, etc. I'm not sure if you saw, but FCA just settled over their V6 diesel used in numerous vehicles here in the US, which had cheater software as well.

The Boeing test pilot who has been indicted will probably go down. He is but one cog in a big machine. The atmosphere where an underling is put in the position to be a single point of destruction / failure for a company like BA should be scrutinized.

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## BiffF15 (Jan 13, 2022)

SaparotRob said:


> BTW. I find it hard to believe McDonnell Douglas would take any short cuts.


I plumbed the DC8 for about a year. Totally archaic plane, but it was state of the art in the day. Interesting thing, as you could look down the side of the fuselage and it was as smooth as glass. No wrinkles. Not bad for a 50 year old broad. Next time you walk aboard an airliner, look at it like you would a car for wrinkles / denting. 

The guys who flew the Eagle liked to brag how tough it was compared to our single engined brethren. I always though if it had come with a hood ornament it would have been a Bulldog (think Mack trucks), or if you scrapped the paint off, it would be yellow and say Tonka all over it. They made tough products, or they rounded up when doing the math...

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## SaparotRob (Jan 13, 2022)

BiffF15 said:


> I plumbed the DC8 for about a year. Totally archaic plane, but it was state of the art in the day. Interesting thing, as you could look down the side of the fuselage and it was as smooth as glass. No wrinkles. Not bad for a 50 year old broad. Next time you walk aboard an airliner, look at it like you would a car for wrinkles / denting.
> 
> The guys who flew the Eagle liked to brag how tough it was compared to our single engined brethren. I always though if it had come with a hood ornament it would have been a Bulldog (think Mack trucks), or if you scrapped the paint off, it would be yellow and say Tonka all over it. They made tough products, or they rounded up when doing the math...


As to your first paragraph, I always check out the plane. No, my car doesn't pass muster. 
As to the second, Tonka made the best playground weapons.

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## Schweik (Jan 13, 2022)

I'm Ok y'all discuss whatever you like. I'm just steering away from certain kinds of arguments personally. The whole debacle with Boeing is quite interesting though.

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## Zsnark (Jan 14, 2022)

pbehn said:


> Th P-51 was designed to be better than the P-40 and others and it was. By 1943 in Europe N Africa the theatres that planes could be used in was diminishing. You could make a better P-40 with a two stage Packard (Merlin) but it wouldnt be as good as a P-51 so it would be a waste of engines and P-51 fuselages which were waiting for engines.


I think you are absolutely correct, why keep propping up an airframe which was new in the mid 30s and use scarce Merlins while you could put them in a great early 40s airframe. the whole "what if" thing is pointless. In my not so humble opinion (IMNSHO).


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## Escuadrilla Azul (Jan 15, 2022)

Those post are what I like about this forum. A thread started about the P-40 in Europe and drift to the Boeing debacle via some pretty technical detour about how temp and high afect performanceand TO, all with first hand knowledge and an informative mood. That is great.

Love you guys!

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## Escuadrilla Azul (Jan 15, 2022)

Risking some groundhogery.

Could the high temp and low air density in New Guinea and Guadalcanal explain partly (beside all other known factors) explain the abysmal difference in performance (real and perceived) of the plane that can't be named and the P-40 in the PTO vs the eastern front?


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## Shortround6 (Jan 15, 2022)

Not quite.
The P-40 and the P-** should not change places. 

If the P-40 and P-** are both running at 95 degrees then they will both perform below book value. 
If the P-40 and P-** are both running at 0-32 degrees than they should both perform above book value.

Now the difference _might_ not be identical (both planes _might_ not drop by 3000ft) but the difference of a few hundred feet out of 3000 shouldn't change the relative standings.
LIke have the P-40 out climb the P-** in one case and climb slower in the other case (weather condition.) 

Remember that the you are also comparing 3-5 planes. The P-40 and P-** are trying to climb in comparison to the A6M (and bombers?) and both are going to climb worse than the A6M (and bomber at altitude) even though the A6M is also going to climb worse. Likewise on the Russian front you are trying to see how well the P-40 and P-** climb in relation to the Bf 109 as main adversary. 

open to correction.

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## Escuadrilla Azul (Jan 15, 2022)

Shortround6 said:


> Not quite.
> The P-40 and the P-** should not change places.
> 
> If the P-40 and P-** are both running at 95 degrees then they will both perform below book value.
> ...


I think I didn't explain very well but nevertheless you answered my question.

I was thinking if the temp difference between NG and Cactus and the eastern front could explain the difference in performance of the P-40 and the P-40 minus one in both theathers, been both "below book value" in the tropics and "above book value" in the USSR, rather than the P-38 plus one been better than the P-40 in northern latitudes.

Anyway, thanks!


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## tomo pauk (Jan 15, 2022)

My take: if one's aircraft already have problems of unfavorable power-to-weight ratio, especially at higher altitudes - talk above 15000 ft in the SW Pacific in 1942 - these problems will be even worse when trying to operate in the climate of the region.


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## Shortround6 (Jan 15, 2022)

Well, if our pilot friends are correct ( I am assuming they are) you may see around a 3,000ft drop in critical altitude (FTH) but this is not going to show up on the instruments.
Or rather the Manifold pressure gauge may say you are getting 42in at 2600rpm (or what ever) but you are not getting the mass of air at the pressure that you will get at a lower temperature. Watching your altimeter may show that you are not climbing at the rate of climb you are expecting for the manifold pressure. 
You also have to fly a bit faster to actually equal the true airspeed and now we get into is the plane making less drag in the thinner air or is it the 
increase in the incident of the wing providing more lift at similar speed cancel things out?

Your P-40 may be climbing several hundred fpm slower, but from the pilots view point that Zero (which is also climbing several hundred FPM slower) above him is still climbing faster than the P-40.

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## FLYBOYJ (Jan 15, 2022)

Escuadrilla Azul said:


> Risking some groundhogery.
> 
> Could the high temp and low air density in New Guinea and Guadalcanal explain partly (beside all other known factors) explain the abysmal difference in performance (real and perceived) of the plane that can't be named and the P-40 in the PTO vs the eastern front?


Density altitude limitations effect *ALL* aircraft and are well known to the pilots operating them - *and effects the enemy's aircraft as well.*


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## tomo pauk (Jan 15, 2022)

FLYBOYJ said:


> Density altitude limitations effect *ALL* aircraft and are well known to the pilots operating them - *and effects the enemy's aircraft as well.*



Problem might be that Japanese aircraft were already at 17-18 kft after their 300-500 mile ccruise towards the NG and Guadalcanal. Allied fighters need to take off and climb under more difficult circumstances than it will be the case in Alaska or Connecticut. P-40 and P-39 will be worse in this job (climb to 18000 ft) than the Spitfire or F4F, and even those two were not stellar.


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## FLYBOYJ (Jan 15, 2022)

tomo pauk said:


> Problem might be that Japanese aircraft were already at 17-18 kft after their 300-500 mile ccruise towards the NG and Guadalcanal. Allied fighters need to take off and climb under more difficult circumstances than it will be the case in Alaska or Connecticut. P-40 and P-39 will be worse in this job (climb to 18000 ft) than the Spitfire or F4F, and even those two were not stellar.


Exactly. Thus the need for an interceptor with better across the board performance, possibly turbo-supercharged with a great climbing ability. Can we guess what might fill that role?

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## Schweik (Jan 15, 2022)

Shortround6 said:


> Not quite.
> The P-40 and the P-** should not change places.
> 
> If the P-40 and P-** are both running at 95 degrees then they will both perform below book value.
> ...



I suspect this may actually have something to do with it. The early P-39s and P-40s were both underpowered and overloaded. Just at the tipping point. P-39 was a bit lighter but they had shorter and smaller wings

It sounds like field-stripping started a bit earlier with P-40s (as early as Java) and overboosting was already being done by Aussie units by the time of Milne Bay (summer 1942). Meanwhile the P-39s were being shipped with those extra guns in the outer wings, which I don't think they stripped those off right away. With the F4F, they were lucky in that the original F4F-3, used up to Midway, was the peppier one (before the folding wings and extra guns).

*Early Allied Fighters*
F4F-3 has a 38' wing span with a 260' wing area. Loaded weight was about 7,300 lbs for a 28 lb / sq ft wing loading
P-40E has a 37' wing span with a 236' wing area. Loaded weight was about 8,000 lbs for a 33 lb / sq ft (171 kg/m2) wing loading
F2A has a 35' wing span and a 206' wing area. Loaded weight was about 6,800 lbs for a 34 lb / sq fit wing loading
P-39D has a 34' wing span and a 213' wing area. Loaded weight was about 7,800 lbs for a 36 lb / sq ft wing loading (this is with the wing guns)

*Early Japanese Fighters*
A5M2 has a 36' wing span with a 192' wing area, loaded weight was about 3,500 lbs for a 19 lb / sq ft wing loading
A6M2 has a 39' wing span with a 241' wing area. Loaded weight was about 6,000 lbs for a 21 lb / sq ft wing loading
Ki-27 has a 37' wing span with a 200' wing area. Loaded weight was about 3,500 lbs for a 18 lb / sq ft wing loading
Ki-43 has a 35' wing span with a 230' wing area. Loaded weight was about 5,500 lbs for a 25 lb / sq ft wing loading (plus auto-flaps)

So based on that, the Japanese fighters seem much better suited to Tropical conditions.

A few lbs difference in wing loading between the Allied types may not seem like much but as I said, all the Allied fighter types were right at the tipping point, a difference of ~300 lbs or 150 hp or so seems to have made a huge jump in rate of climb, top speed etc. The Finns also experienced this with their lighter variant of the F2A. I suspect the P-39 units were lagging a bit in modifying their crates, and they already had the shortest wings and highest wing loading of the major US fighter types.

P-39 didn't do quite as badly in the Pacific as their reputation, they did get some victories (a bit over 300 claims). They definitely did better there than in the MTO. But only one (American) Ace, which is pretty telling.

Conversely, not all the P-39 units did so well in Soviet use. There were a couple which got started in the Kuban zone (which is down in the Taman peninsula on the Black Sea, in Southern Russia) in the Summer, and they didn't do so well. I wonder if climatic conditions played a role in that.


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## Schweik (Jan 15, 2022)

tomo pauk said:


> Problem might be that Japanese aircraft were already at 17-18 kft after their 300-500 mile ccruise towards the NG and Guadalcanal. Allied fighters need to take off and climb under more difficult circumstances than it will be the case in Alaska or Connecticut. P-40 and P-39 will be worse in this job (climb to 18000 ft) than the Spitfire or F4F, and even those two were not stellar.



Sometimes, but it depended on what kind of bombing they were doing. If they were coming over with level bombers (G3M, G4M, Ki-21) they might stay at that altitude, if they were doing dive bombing, torpedo bombing or strafing they would come down much lower. The Allies also developed a fairly effective coast watcher network after the first few months and often got warning early enough to climb to altitude before the Japanese got there (even with the very slow-climbing types).


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## Schweik (Jan 15, 2022)

FLYBOYJ said:


> Exactly. Thus the need for an interceptor with better across the board performance, possibly turbo-supercharged with a great climbing ability. Can we guess what might fill that role?
> 
> View attachment 654715



It helps explain why the P-38 did so well in the PTO. The extra power really helped.


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## FLYBOYJ (Jan 15, 2022)

Schweik said:


> So based on that, the Japanese fighters seem much better suited to Tropical conditions.


Not really and don't over think this

As mentioned, density altitude (DA) effects EVERY aircraft. If you have an aircraft that's a poor climber to begin with, it's performance will be diminished even more based on the severity of the DA for that given day. Take off weight will definitely have a play into this, but you also have to consider how the aircraft is set up for climb performance. Available HP and wing design are also part of the equation.


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## FLYBOYJ (Jan 15, 2022)

Schweik said:


> It helps explain why the P-38 did so well in the PTO. The extra power really helped.


And in general PTO pilots were better trained


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## Schweik (Jan 15, 2022)

FLYBOYJ said:


> Not really and don't over think this
> 
> As mentioned, density altitude (DA) effects EVERY aircraft equally. If you have an aircraft that's a poor climber to begin with, it's performance will be diminished based on the severity of the DA for that given day. Take off weight will definitely have a play into this, but you also have to consider how the aircraft is set up for climb performance. Available HP and wing design are also part of the equation.



Right, but I'm just saying that the Japanese types seemed to have a much more comfortable margin. P-40 and P-39 are going to be starting to lose power at 10,000 ft in Tropical heat. They are close to the tipping point both for power loading and wing loading which if degraded by the equivalent of 3,000 ft, would affect takeoff and climb, right? The Japanese fighters already had an altitude advantage, but the 'comfortable zone' for the US types would be greatly compressed in high heat.

This affects not only engines but also airframes. When it comes to a stall, doesn't thinner air play a role? If you have an aircraft with a propensity to spin, and you have just effectively placed it 3,000 feet higher, wouldn't the odds of a spin go up?

The P-38 had high wing loading but a lot of extra power to call upon, and you make a good point about the training. The P-38 pilots went through operational training units. Many of the P-39 and P-40 pilots were barely trained on type. Both US 49th FG the Australian 75th FS had most of their pilots going into battle with less than 30 hours on a P-40, they literally got their training flying to the battle area (and lost half of their planes along the way in landing accidents, as many of them hadn't gotten used to retractable landing gear).

P-38 is a much more complex aircraft but I bet the extra training (often with pilots who already had combat experience in other types, like Bong and McGuire) really helped.


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## FLYBOYJ (Jan 15, 2022)

Schweik said:


> Right, but I'm just saying that the *Japanese types seemed to have a much more comfortable margin. *P-40 and P-39 are going to be starting to lose power at 10,000 ft in Tropical heat. They are close to the tipping point both for power loading and wing loading which if degraded by the equivalent of 3,000 ft, would affect takeoff and climb, right? The Japanese fighters already had an altitude advantage, but the 'comfortable zone' for the US types would be greatly compressed in high heat.


But that "margin' would generally be the same if they were flying in 100F at 98% humidity as if they were in 32F at 10% humidity


Schweik said:


> This affects not only engines but also airframes. When it comes to a stall, doesn't thinner air play a role?


No - the aircraft will stall at the same indicated airspeeds for a given configuration.

_"At higher altitudes, the air density is lower than at sea level. Because of the progressive reduction in air density, as the aircraft's altitude increases its true airspeed is progressively greater than its indicated airspeed. For example, the indicated airspeed at which an aircraft stalls can be considered constant, but the true airspeed at which it stalls increases with altitude."_



Schweik said:


> If you have an aircraft with a propensity to spin, and you have just effectively placed it 3,000 feet higher, wouldn't the odds of a spin go up?


No, same as stalling.

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## gordonm1 (Jan 15, 2022)

Escuadrilla Azul said:


> Risking some groundhogery.
> 
> Could the high temp and low air density in New Guinea and Guadalcanal explain partly (beside all other known factors) explain the abysmal difference in performance (real and perceived) of the plane that can't be named and the P-40 in the PTO vs the eastern front?


I thought a major point was one type was not equipped for oxygen and limited to 12,000 feet and the other was and not limited to 12,000.


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## FLYBOYJ (Jan 15, 2022)

gordonm1 said:


> I thought a major point was one type was not equipped for oxygen and limited to 12,000 feet and the other was and not limited to 12,000.


That would be more of an operational situation. The lack of O2 was based on the configuration of the aircraft being operated.


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## Simon Thomas (Jan 15, 2022)

Schweik said:


> This affects not only engines but also airframes. When it comes to a stall, doesn't thinner air play a role? If you have an aircraft with a propensity to spin, and you have just effectively placed it 3,000 feet higher, wouldn't the odds of a spin go up?


I've got some time in a Victa Airtourer 100. When I did stalls for training, I was around 3,000 ft. 
One day for giggles, my brother and I took it up to 10,000 ft. Due to its small wing area and 100 hp O-200, it has a rather poor climb rate. We got to 10,000 ft after a very long hour. ATC thought we were never going to make it.
Once we got their, we didn't know what to do - so with all the wisdom that a pair of teenagers could muster, we stalled it.
The stall was at the usual IAS, but bugger me it was different. Instead of the usual waffle and nose drop, it dropped a wing and despite almost instant full rudder to catch it - that wing kept going. It got past 90° very quickly. We eventually got right side up and wings level, but dropped a few thousand feet in the process.

Getting back to the question, any planes controls are less effective at altitude. The impact on the planes performance is likely related to the way wing loading and power loading decay with altitude.

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## Greg Boeser (Jan 15, 2022)

Schweik said:


> Right, but I'm just saying that the Japanese types seemed to have a much more comfortable margin. P-40 and P-39 are going to be starting to lose power at 10,000 ft in Tropical heat. They are close to the tipping point both for power loading and wing loading which if degraded by the equivalent of 3,000 ft, would affect takeoff and climb, right? The Japanese fighters already had an altitude advantage, but the 'comfortable zone' for the US types would be greatly compressed in high heat.
> 
> This affects not only engines but also airframes. When it comes to a stall, doesn't thinner air play a role? If you have an aircraft with a propensity to spin, and you have just effectively placed it 3,000 feet higher, wouldn't the odds of a spin go up?
> 
> ...


49th Pursuit Group absorbed many survivors of the Phillipines and Java, skimmed the cream of the newly arrived replacement pilots, and early on, served in an air defense role in the Darwin area, flying a single type, armed with a single weapon type, thereby simplifying maintenance. 
8th and 35th Pursuit Groups were equipped with a variety of models of Airacobra, P-400s, P-39D ( of different blocks), P-39F. These were armed with three different weapons, vastly complicating supply and maintenance requirements. Plus, their theater of operations, defending Port Moresby, and conducting offensive operations across the Owen Stanleys, was a much more challenging one. P-38 squadrons being stood up or converting from other types got to cherry pick the best and brightest veteran pilots.

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## FLYBOYJ (Jan 15, 2022)

Simon Thomas said:


> I've got some time in a Victa Airtourer 100. When I did stalls for training, I was around 3,000 ft.
> One day for giggles, my brother and I took it up to 10,000 ft. Due to its small wing area and 100 hp O-200, it has a rather poor climb rate. We got to 10,000 ft after a very long hour. ATC thought we were never going to make it.
> Once we got their, we didn't know what to do - so with all the wisdom that a pair of teenagers could muster, we stalled it.
> The stall was at the usual IAS, but bugger me it was different. Instead of the usual waffle and nose drop, it dropped a wing and despite almost instant full rudder to catch it - that wing kept going. It got past 90° very quickly. We eventually got right side up and wings level, but dropped a few thousand feet in the process.
> ...


This is more due to power loading decay IMO. I've flown C150s, 152s and 172s at altitudes in excess in 10,000' (I live at 6000' MSL) and generally felt no difference in stall/ spin recovery at higher altitudes than I would a bit lower. Now when I visit friends who reside close to sea level and have an opportunity to fly with them, I notice the performance difference, especially on take off.

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## Schweik (Jan 15, 2022)

That was the P-400, it was P-39 fitted out to British specs and the O2 systems weren't compatible.

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## Schweik (Jan 15, 2022)

Simon Thomas said:


> I've got some time in a Victa Airtourer 100. When I did stalls for training, I was around 3,000 ft.
> One day for giggles, my brother and I took it up to 10,000 ft. Due to its small wing area and 100 hp O-200, it has a rather poor climb rate. We got to 10,000 ft after a very long hour. ATC thought we were never going to make it.
> Once we got their, we didn't know what to do - so with all the wisdom that a pair of teenagers could muster, we stalled it.
> The stall was at the usual IAS, but bugger me it was different. Instead of the usual waffle and nose drop, it dropped a wing and despite almost instant full rudder to catch it - that wing kept going. It got past 90° very quickly. We eventually got right side up and wings level, but dropped a few thousand feet in the process.
> ...



Right, exactly. And planes with a higher wing loading and relatively poor power loading are going to have more problems like that at lower altitudes in hot weather, it seems to me.


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## FLYBOYJ (Jan 15, 2022)

Schweik said:


> Right, exactly. And planes with a higher wing loading and relatively poor power loading are going to have more problems like that at lower altitudes in hot weather, it seems to me.


But power loading is going to be the critical factor. In the example shown that 100 hp O-200 was probably only producing 60 HP at altitude, thus the reason for the poor climb


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## Schweik (Jan 15, 2022)

Greg Boeser said:


> 49th Pursuit Group absorbed many survivors of the Phillipines and Java, skimmed the cream of the newly arrived replacement pilots, and early on, served in an air defense role in the Darwin area, flying a single type, armed with a single weapon type, thereby simplifying maintenance.



I don't think that was the case. Quoting directly from this article:









The USAAF 49th Fighter Group over Darwin: a forgotten campaign | The Strategist


This year has seen many 75th anniversaries of battles and campaigns from the darkest hours of 1942, with the Battle of the Coral Sea (4 to 8 May) prominent. But in all these commemorative activities ...




www.aspistrategist.org.au





_"By April, the 49th, under the command of Lieutenant Colonel Paul Wurtsmith, was in situ, with its three squadrons, the 9th, 8th and 7th, located at Livingstone, Strauss and Batchelor, respectively.

Wurtsmith was a career officer, specialising in 'pursuit' operations. He was a graduate of the USAAC Tactical School with 4,800 flying hours. His executive officer, Major Don Hutchinson, was another pursuit specialist with 2,500 flying hours. The 49th Fighter Group was fortunate to have such experienced leaders, plus a handful of veterans from the Philippines campaign, but that only masked the inexperience of the group, as *out of its initial strength of 102 pilots, 95 had never flown the P-40 before.*"_



Greg Boeser said:


> 8th and 35th Pursuit Groups were equipped with a variety of models of Airacobra, P-400s, P-39D ( of different blocks), P-39F. These were armed with three different weapons, vastly complicating supply and maintenance requirements. Plus, their theater of operations, defending Port Moresby, and conducting offensive operations across the Owen Stanleys, was a much more challenging one. P-38 squadrons being stood up or converting from other types got to cherry pick the best and brightest veteran pilots.



The 49th FG was also stationed at Port Moresby, and also had to fly over the Owen Stanleys, as was the Aussie 74th and 75th FS (also equipped with P-40s). One of the first P-38 squadrons in Theater was one of the 49th FG squadrons, 9th FS, but they did get to train on type.

However I hear what you are saying there about the various types of P-39s, especially the P-400s which had a lot of differences, ammunition, O2 system etc..

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## Schweik (Jan 15, 2022)

FLYBOYJ said:


> But power loading is going to be the critical factor. In the example shown that 100 hp O-200 was probably only producing 60 HP at altitude, thus the reason for the poor climb



Power loading is also affected by the DA right? I'll take your word for it about wing loading being a factor (or not) as well. Seems like it would make a difference but I'm not a pilot.


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## Greg Boeser (Jan 15, 2022)

Pressure altitude affects all aircraft the same, so it really isn't a factor. Unless there are clouds and mountains around. That's when things get "interesting".


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## Schweik (Jan 15, 2022)

Well as you know, in NG and Solomons, there were both


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## FLYBOYJ (Jan 15, 2022)

Schweik said:


> Power loading is also affected by the DA right? I'll take your word for it about wing loading being a factor (or not) as well. Seems like it would make a difference but I'm not a pilot.


It is - but if you have power to keep airflow over the wings (regardless of the wing loading) you're going to stay airborne.


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## Schweik (Jan 15, 2022)

FLYBOYJ said:


> This is more due to power loading decay IMO. I've flown C150s, 152s and 172s at altitudes in excess in 10,000' (I live at 6000' MSL) and generally felt no difference in stall/ spin recovery at higher altitudes than I would a bit lower. Now when I visit friends who reside close to sea level and have an opportunity to fly with them, I notice the performance difference, especially on take off.



Could that possibly be because Cessna 150-172 etc. have very good stall characteristics and a low wing loading?

I get that it affects all aircraft equally, but (I guess I'm missing something here but I don't see it yet) it seems like an aircraft which was already kind of on the edge of being hard to control and / or 'twitchy' would have more trouble in the degraded (thin / hot air) conditions than one with a very good wing loading that was easy to handle.


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## Schweik (Jan 15, 2022)

Don't aircraft with larger wings handle better at high altitude? Isn't that why they had the HF and LF Spitfire, the former having the extended wing tips?


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## FLYBOYJ (Jan 15, 2022)

Greg Boeser said:


> Pressure altitude affects all aircraft the same, so it really isn't a factor. Unless there are clouds and mountains around. That's when things get "interesting".


Pressure altitude is the height above a standard datum plane based on a barometric pressure. That's what you would adjust your altimeter to based on airfield pressure. With that known you can calculate your DA


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## FLYBOYJ (Jan 15, 2022)

Schweik said:


> Don't aircraft with larger wings handle better at high altitude? Isn't that why they had the HF and LF Spitfire, the former having the extended wing tips?
> 
> View attachment 654739


Yes - because now you have a larger wing area to support the aircraft. Your lift coefficient will be higher. That's why gliders (and other aircraft) have long wings.

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## FLYBOYJ (Jan 15, 2022)

Schweik said:


> Could that possibly be because Cessna 150-172 etc. have very good stall characteristics and a low wing loading?


Compared to a Victa Airtourer 100 possibly. The 150/ 152 has little dihedral so the stall is more abrupt and a wing tends to drop, but you want that in a trainer. The 172 stalls a bit cleaner


Schweik said:


> I get that it affects all aircraft equally, but (I guess I'm missing something here but I don't see it yet) it seems like an aircraft which was already kind of on the edge of being hard to control and / or 'twitchy' would have more trouble in the degraded (thin / hot air) conditions than one with a very good wing loading that was easy to handle.


To a point, again, how much air is being pushed over the wing? That's where the power factor comes into play.


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## FLYBOYJ (Jan 15, 2022)

Schweik said:


> Don't aircraft with larger wings handle better at high altitude? Isn't that why they had the HF and LF Spitfire, the former having the extended wing tips?
> 
> View attachment 654739


Here's more on this;









Lift-to-drag ratio - Wikipedia







en.wikipedia.org

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## Schweik (Jan 15, 2022)

FLYBOYJ said:


> Compared to a Victa Airtourer 100 possibly. The 150/ 152 has little dihedral so the stall is more abrupt and a wing tends to drop, but you want that in a trainer. The 172 stalls a bit cleaner



Cessna 172 is the only one I ever flew, it seemed very gentle. Parasol wing, low wing loading etc. In spite of quite low power.



FLYBOYJ said:


> To a point, again, how much air is being pushed over the wing? That's where the power factor comes into play.



What I meant is, a Cessna (of any kind) has very benign stall characteristics and very low wing loading compared to a P-39 for sure right?

If the HF Spitfire had it's wing extended by 4 feet to improve handling in thin air, and the P-39 has a wingspan 5 feet shorter than an A6M2, 4 feet shorter than an F4F-3, and 3 feet shorter than a P-40, it stands to reason that at _some _altitude, the wing will play a role in higher altitude / more severe DA conditions. Ratios are similar vis a vis wing area and wing loading.

The question would then be at what altitude would that start to become noticeable or telling? 

Otherwise if it's just a matter of power to weight ratio, P-39 looks pretty good.


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## FLYBOYJ (Jan 15, 2022)

Schweik said:


> What I meant is, a Cessna (of any kind) has very benign stall characteristics and very low wing loading compared to a P-39 for sure right?


Yes - it is basically a trainer and designed that way


Schweik said:


> If the HF Spitfire had it's wing extended by 4 feet to improve handling in thin air, and the P-39 has a wingspan 5 feet shorter than an A6M2, 4 feet shorter than an F4F-3, and 3 feet shorter than a P-40, it stands to reason that *at some altitude, the wing will play a role in higher altitude / more severe DA conditions. Ratios are similar vis a vis wing area and wing loading.*


It will and again **Depending how much air is flowing over it**


Schweik said:


> The question would then be at what altitude would that start to become noticeable or telling?


That's is dependent on the aircraft service ceiling


Schweik said:


> Otherwise if it's just a matter of power to weight ratio, P-39 looks pretty good.


But it starts running out of power at around 15,000'


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## Shortround6 (Jan 15, 2022)

Find the tests/reports for the Spitfires, unfortunately only they one compared two sets of tips at the same time. 
There was a difference in the wing tips. However sometimes it was subtle, at least at most altitudes. Like the clipped wingtip not showing much difference until around 20,000ft was reached? Although it improved roll. it is interesting because you should swap the set of tips back and forth if you wanted to. I beleive the Clip version gave you 231/2 sq ft, normal version gave 242 sq ft and the extended tip gave 248.5 so something else beside just wing area was going on. You were altering the aspect ratio of the wing and that can affect actual lift ratio of the whole wing. 
Once you start comparing one wing and fuselage to another you had better know what you are doing.

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## FLYBOYJ (Jan 15, 2022)

Shortround6 said:


> There was a difference in the wing tips. However sometimes it was subtle, at least at most altitudes. Like the clipped wingtip not showing much difference until around 20,000ft was reached? Although it improved roll. it is interesting because you should swap the set of tips back and forth if you wanted to. I beleive the Clip version gave you 231/2 sq ft, normal version gave 242 sq ft and the extended tip gave 248.5 so something else beside just wing area was going on. You were altering the aspect ratio of the wing and that can affect actual lift ratio of the whole wing.
> Once you start comparing one wing and fuselage to another you had better know what you are doing.


When I crewed at Reno, we had custom wingtips with a slight upward slope designed by some Scale Composites folks. They gave us better roll rates but we lost a few MPH. After flying one race and almost getting passed by another aircraft, we put the stock wingtips back.

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## Schweik (Jan 15, 2022)

Shortround6 said:


> Find the tests/reports for the Spitfires, unfortunately only they one compared two sets of tips at the same time.
> There was a difference in the wing tips. However sometimes it was subtle, at least at most altitudes. Like the clipped wingtip not showing much difference until around 20,000ft was reached? Although it improved roll. it is interesting because you should swap the set of tips back and forth if you wanted to. I beleive the Clip version gave you 231/2 sq ft, normal version gave 242 sq ft and the extended tip gave 248.5 so something else beside just wing area was going on. You were altering the aspect ratio of the wing and that can affect actual lift ratio of the whole wing.
> Once you start comparing one wing and fuselage to another you had better know what you are doing.



Two comments on that - one thing I remember reading in pilot interviews about the HF wingtips, is that they disliked the pointed wingtips due to a very negative impact on roll rates. Which again makes me think of the Soviet complaints about the Hurricanes operating near Lenningrad. 

I could be remembering this wrong but IIRC LF Spitfires were not doing so well by 20,000 ft due to the engines (Merlin 45M or 50M) critical altitude. 

For example this chart for a Spit VB with a Merlin 50M tops out at 350 mph and +15lb boost at just below 6,000 ft. By 20'000 ft it's down to 337 mph and +5 lb boost.

Compare this to a Spit V with a Merlin 45 making 372 mph at 20,000 ft with +9 lb boost.


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## PAT303 (Jan 15, 2022)

Schweik said:


> Two comments on that - one thing I remember reading in pilot interviews about the HF wingtips, is that they disliked the pointed wingtips due to a very negative impact on roll rates. Which again makes me think of the Soviet complaints about the Hurricanes operating near Lenningrad.
> 
> I could be remembering this wrong but IIRC LF Spitfires were not doing so well by 20,000 ft due to the engines (Merlin 45M or 50M) critical altitude.
> 
> ...


The MkVII with Merlin 60-70 series was the HF version of the Spit, Spitfire Mk VII Performance.
The V's fitted with Merlin M series engines and clipped wings were LF versions developed to combat the FW190, the M series was purposely developed to give their best performance at low altitude.


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## Schweik (Jan 15, 2022)

I'm well aware of the above, did anything I wrote contradict that?

To clarify - HF Spitfires - good high altitude performance, complaints about roll rate (though I don't know at what altitude)

LF Spitfires, very good at low altitude, not so much at 20,000 ft (contrary to what Shortround6 said)


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## wuzak (Jan 15, 2022)

HF VIII and HF IX had standard wingtips.

Mk.VII had extended wing tips and pressurized cabin, but not many produced.


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## Shortround6 (Jan 15, 2022)

You had HF MK VI Spitfires with Merlin 47 engines and long wing tips and you had low flying Spitfires with single stage cropped impeller engines with clipped tips.

You had MK VIIs with two stage Merlins with long wing tips and a few MK VIIIs with long tips (some of which got regular wing tips later.)

You had a bunch of two stage Merlins with standard tips

There were a few MK IXs with clipped wings and there a few MK XVIEs with clipped wings. 

The LF and HF referred to the engines, not the wing tips


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## Schweik (Jan 15, 2022)

Actually LF and HF seems to have referred to both wingtips and engines, I would say. At least initially.

I know it was complicated - Spitfire variants are complicated, I was referring to it as part of another point. I think you know what I meant.


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## wuzak (Jan 16, 2022)

Schweik said:


> Actually LF and HF seems to have referred to both wingtips and engines, I would say. At least initially.
> 
> I know it was complicated - Spitfire variants are complicated, I was referring to it as part of another point. I think you know what I meant.



Maybe in the case of the Mk V.

The initial Mk.IXs (with Merlin 61s then 63s) were retroactively renamed F.IX, with the later Merlin 66 version becoming the LF.IX and the Merlin 70 version the HF.IX. Similarly the VIII was to become the F.VIII, LF.VIII and HF.VIII. Few of the LF IVs and LF.VIIIs had clipped wings, and few, if any, of the HF.IXs and HF.VIIIs had extended wing tips.

Also note that the IX was the stop-gap 2 stage Merlin Spitfire, the definitive versions being the VII and VIII, the former intended to be the standard high altitude fighter with extended wing tips, and the latter the standard day fighter with standard tips. Only 140 VIIs were built, earlier versions with the Merlin 64 (F.VII) and later versions with the Merlin 71 (HF.VII). The VII used a pressurized cabin, the Merlins they used were essentially the same as those used in the IX and VIII but with cabin blower. Many VIIs would revert to the standard wing tips.

The VI was a similarly high altitude version of the V using a pressurized cabin and the Merlin 47.

There were no HF or LF versions of the Griffon Spitfires.

The XII was a low altitude version on account of its engine, and would often be fitted with clipped wing tips.

The XIV would have clipped wing tips later in its life as some had wrinkling in wing skins, so the MAP ordered they have the clipped wing tips, though Supermarine said it was unnecessary.

Note that in tests it was shown that the clipped wing tips improved roll rate, but decreased climb rate, ceiling, turning radii and top speeds.

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## Greg Boeser (Jan 16, 2022)

Decreased turn radii? I would have thought increased.


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## Schweik (Jan 16, 2022)

Shorter wings means less wing area therefore higher wing loading. But even an LF (short winged) Spitfire still turned pretty well compared to most other fighters.


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## Schweik (Jan 16, 2022)

My original point, less it be lost in the interesting details about the Spitfire variants, is that a few feet of wing seemed to make a difference vis a vis high and low altitude performance. The longer wings on the spit conferred greater high altitude performance, I think they ended up being dropped because they had such an adverse effect on roll rates (am I right about that?)

This is still getting back to the idea of the relatively small winged P-39, with it's 34' wing span, flying in the Tropics vs Central Asia.


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## wuzak (Jan 16, 2022)

Greg Boeser said:


> Decreased turn radii? I would have thought increased.



Yes, that's what I meant. Thanks.


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## Shortround6 (Jan 16, 2022)

As I mentioned, it is a good illustration of the difference wings can make. 

The wing itself didn't change, there were no change to flaps or slats. 
From smallest to largest there was under 4% in wing area. 

Your major changes are to aspect ratio and the inset to the ailerons.
They tried them from sea level well into the 30,000ft range. 
The difference in weight was minimal.

They should provide clues to other wings.

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## Schweik (Jan 16, 2022)

Good point about the ailerons - having the wingtips extended beyond them is a pretty unusual design feature for any aircraft. That may account for the bad roll rate more than just the wingspan...


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## FLYBOYJ (Jan 16, 2022)

Schweik said:


> *Good point about the ailerons - having the wingtips extended beyond them is a pretty unusual design feature for any aircraft. *That may account for the bad roll rate more than just the wingspan...


????

I think you'll find that many aircraft have wingtips that extend beyond the ailerons!

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## Schweik (Jan 16, 2022)

Yeah but this is a big more substantial than a faring


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## FLYBOYJ (Jan 16, 2022)

Schweik said:


> Yeah but this is a big more substantial than a faring


It is - but you'll still find that on the majority of ALL aircraft the WINGTIP extends beyond the aileron.

AND - a wingtip "is not" a fairing.


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## pbehn (Jan 16, 2022)

Schweik said:


> Good point about the ailerons - having the wingtips extended beyond them is a pretty unusual design feature for any aircraft. That may account for the bad roll rate more than just the wingspan...


Even with its standard wing tips the Spitfires roll rate wasnt bad, its problem was it was facing the Fw 190 which was pretty much the best in class. The extended wing tips were fitted to get to a higher altitude, rate of roll isnt a consideration when you cant even fly straight and level.

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## Schweik (Jan 16, 2022)

FLYBOYJ said:


> It is - but you'll still find that on the majority of ALL aircraft the WINGTIP extends beyond the aileron.
> 
> AND - a wingtip "is not" a fairing.



I'd say the HF type wing was the longest 'wingtip' around, by a good margin.


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## FLYBOYJ (Jan 16, 2022)

Schweik said:


> I'd say the HF type wing was the longest 'wingtip' around, by a good margin.


For a WW2 fighter - possibly.

Gliders have huge wingtips and in some cases put on separately when the glider is assembled for flight.


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## Schweik (Jan 16, 2022)

Correct me if I'm wrong, but gliders are typically made to be very stable and not necessarily for fast rolling right?


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## FLYBOYJ (Jan 16, 2022)

Schweik said:


> Correct me if I'm wrong, but gliders are typically made to be very stable and not necessarily for fast rolling right?


No - there are many gliders designed for aerobatics and for their wingspans have pretty good roll rates around 90°/sec .

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## Schweik (Jan 16, 2022)

That does look like pretty fast rolling

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## BiffF15 (Jan 16, 2022)

SR6 & FBJ are correct regards aircraft performance and pressure altitude. I tried to explain it in a previous post but think they did a better job spelling it out.

FBJ also brings up a point with the P-38 / P-47 and turbocharging. With the two stage engines (supercharging) you see a notch in the climb chart where the switch from low to high blower occurs. In


FLYBOYJ said:


> No - there are many gliders designed for aerobatics and for their wingspans have pretty good roll rates around 90°/sec .



Ugh! He likes the negative stuff!

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## tomo pauk (Jan 16, 2022)

BiffF15 said:


> FBJ also brings up a point with the P-38 / P-47 and turbocharging. With the two stage engines (supercharging) you see a notch in the climb chart where the switch from low to high blower occurs. In


Probably there is a part of latest sentence that is missing?
The notch in the climb chart is not due to the engines having 2-_stage_ superchargers, but due to the 2-_speed_ drive for the said superchargers. Same feature is present on 2-speed 1-stage superchargers, eg. on engines powering the the Hurricane II, P-40F, Yak fighters, Fw 190, or F8F-1.
Enines with 2-stage supercharging have had the S/C drives with 2-speed gearing (as on the Merlin 60/70/100/130 series), or 3-speed gearing (Jumo 213E and F; the P&W engines with 2-stage S/Cs sorta fall in this category), or one or both stages were driven via hydraulic coupling (= infinite number of speeds in theory; the V-1710 on P-63 and P-82E, DB 603L and 605L, VK-105PD).

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## BiffF15 (Jan 16, 2022)

tomo pauk said:


> Probably there is a part of latest sentence that is missing?
> The notch in the climb chart is not due to the engines having 2-_stage_ superchargers, but due to the 2-_speed_ drive for the said superchargers. Same feature is present on 2-speed 1-stage superchargers, eg. on engines powering the the Hurricane II, P-40F, Yak fighters, Fw 190, or F8F-1.
> Enines with 2-stage supercharging have had the S/C drives with 2-speed gearing (as on the Merlin 60/70/100/130 series), or 3-speed gearing (Jumo 213E and F; the P&W engines with 2-stage S/Cs sorta fall in this category), or one or both stages were driven via hydraulic coupling (= infinite number of speeds in theory; the V-1710 on P-63 and P-82E, DB 603L and 605L, VK-105PD).


Tomo,

I thought I deleted that second paragraph. I was starting to speak to some questions that Schweik brought up regards pressure altitude, wingspan and performance but after re-reading FBJs and SR8s replies decided to skip it. I failed proofreading it would appear!

Biff


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## XBe02Drvr (Jan 17, 2022)

BiffF15 said:


> Ugh! He likes the negative stuff!


That's where it's at, Man! (Out to ten seconds, anyway.)

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## Schweik (Jan 17, 2022)

Until your eyeballs turn bright red!


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## XBe02Drvr (Jan 17, 2022)

Schweik said:


> Until your eyeballs turn bright red!


Actually it takes a bit more than steady state negative 1 G to red you out. I didn't see any "outside" maneuvers in that acro sequence. Even one negative sustained gets pretty old pretty quick. After 10-15 seconds it stops being fun. And in a glider you're surrendering altitude pretty quick in sustained inverted flight, unless you've got one designed specifically for acro which sacrifices some of its upright performance for a symmetrical airfoil. $$$!

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## FLYBOYJ (Jan 17, 2022)

When I first stared flying I had air sickness issues traced to possible inner ear damage. I was able to overcome that and was able to handle adverse maneuvers. In my 30s I started doing some aerobatic training and it didn't bother me too much. These days - no way!

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## Schweik (Jan 17, 2022)

I've experienced some negative G in a Cessna 172, was unpleasant. We all know the feeling (a bit) from elevators. Steady 2G in the Cessna was really interesting...

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## Thumpalumpacus (Jan 17, 2022)

My gonads should not be introducing themselves to my colon. I'm pretty simple that way.

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## XBe02Drvr (Jan 17, 2022)

Schweik said:


> I've experienced some negative G in a Cessna 172, was unpleasant. We all know the feeling (a bit) from elevators. Steady 2G in the Cessna was really interesting...


Actual negative? Or just zero G? I've done inverted flight (briefly) in a 150 Acrobat, but it turns into a glider muy pronto inverted. Positive G airplane. Your steady 2 G in a 172 had to have been positive and in a 60° bank. A 172 can't sustain a steady 2 Gs any other way. Routine training maneuver prepping for accelerated stalls.

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## gordonm1 (Jan 17, 2022)

The USA stayed out of Europe until Torch got things going in North Africa. Really, other than Service in the Med and Italy there was no need for USA fighters in Europe other than bomber escort until DDay June 1944. The P40 was history as a front line fighter by then and we did well with the latest versions of P47, P38, and P51. Much of P40 production went to China, Burma, Australia, New Zealand and Russia until D Day in France.


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## Schweik (Jan 17, 2022)

XBe02Drvr said:


> Actual negative? Or just zero G? I've done inverted flight (briefly) in a 150 Acrobat, but it turns into a glider muy pronto inverted. Positive G airplane. Your steady 2 G in a 172 had to have been positive and in a 60° bank. A 172 can't sustain a steady 2 Gs any other way. Routine training maneuver prepping for accelerated stalls.



Yes... just nosing over I think... the instructor said it was negative G, I thought I remembered an actual gauge but maybe that is my memory failing. The 2G (positive) was in a sustained bank turn. I remember trying to lift my left hand off my lap and it as amazingly heavy.


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## Schweik (Jan 17, 2022)

gordonm1 said:


> The USA stayed out of Europe until Torch got things going in North Africa. Really, other than Service in the Med and Italy there was no need for USA fighters in Europe other than bomber escort until DDay June 1944. The P40 was history as a front line fighter by then and we did well with the latest versions of P47, P38, and P51. Much of P40 production went to China, Burma, Australia, New Zealand and Russia until D Day in France.



North Africa was fairly important though I would say, and certainly on a large scale (which people tend to forget about). Second El Alamein involved 116,000 Axis troops with 547 tanks (losing 500) vs. 195,000 Allied troops and 1029 tanks (also losing 500. 

Axis forces lost 620,000 troops (killed or captured) in the NA Campaign, not counting Sicily or Italy. The British lost 220,000, the Americans about another 20,000.

P-40s played a pretty big role in that Allied victory.

By comparison the Axis lost 165,000 men in Kursk, the Soviets lost 250,000 (plus another 600,000 wounded or seriously ill)

Stalingrad was bigger though - Axis 750,000 men, Soviets 1,129,000


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## BiffF15 (Jan 17, 2022)

Schweik said:


> Yes... just nosing over I think... the instructor said it was negative G, I thought I remembered an actual gauge but maybe that is my memory failing. The 2G (positive) was in a sustained bank turn. I remember trying to lift my left hand off my lap and it as amazingly heavy.


You would be surprised how fast the human body can adapt. The F-15 F16 both have 9G limits, and you routinely pull 5-7 without dog fighting. Moving your head around works up until about 7, then you want to make sure it's aligned before going further. Talking, flying, tactics, running the radar, shooting all becomes second nature.

G tolerance is interesting. Most folks have about a 4G resting, or when they start to experience graying out. Marathoners will have lower, body builder types higher. We did the centrifuge while at Lead In Fighter Training (LIFT) at Holloman AFB. One of the guys in my class had a 6.5G resting tolerance. He had played football for Texas A&M. The techs were all amazed.

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## FLYBOYJ (Jan 17, 2022)

XBe02Drvr said:


> Actual negative? Or just zero G? I've done inverted flight (briefly) in a 150 Acrobat, but it turns into a glider muy pronto inverted. Positive G airplane. Your steady 2 G in a 172 had to have been positive and in a 60° bank. A 172 can't sustain a steady 2 Gs any other way. Routine training maneuver prepping for accelerated stalls.


This is about the extent of high G maneuvers I'm willing to deal with these days!

This was taken about 23 years ago. I used to help the owner with maintenance and his annual condition inspection. This was an FCF where we got the system for the G suits working, so we went and tried it out. I can't remember how many Gs we pulled but it's a little un-nerving seeing those tip tanks flop around when you're yanking and banking!

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## Thumpalumpacus (Jan 17, 2022)

gordonm1 said:


> Really, other than Service in the Med and Italy there was no need for USA fighters in Europe other than bomber escort until DDay June 1944.



Yabut that need was urgent and realized by late summer 1943. The P-40 wasn't able to cut that, good as it was in other regimes of flight.

Was just today reading Elmer Bendiner's chapter about his group's attack on Schweinfurt in Aug 43. Unescorted due to SNAFU so jagdwaffen lined up and took shots for about 400 miles. That was where the need for fighters came to belated light. "Give us fighters, goddamnit".

230 B-17s flew to Schweinfurt that day. 170 returned, and another 17 never flew again.

There was certainly a need for USA fighters in Europe -- if only for the bombers and nothing else -- in my view.

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## gordonm1 (Jan 17, 2022)

Schweik said:


> North Africa was fairly important though I would say, and certainly on a large scale (which people tend to forget about). Second El Alamein involved 116,000 Axis troops with 547 tanks (losing 500) vs. 195,000 Allied troops and 1029 tanks (also losing 500.
> 
> Axis forces lost 620,000 troops (killed or captured) in the NA Campaign, not counting Sicily or Italy. The British lost 220,000, the Americans about another 20,000.
> 
> ...


Yes and the British got more 


Schweik said:


> North Africa was fairly important though I would say, and certainly on a large scale (which people tend to forget about). Second El Alamein involved 116,000 Axis troops with 547 tanks (losing 500) vs. 195,000 Allied troops and 1029 tanks (also losing 500.
> 
> Axis forces lost 620,000 troops (killed or captured) in the NA Campaign, not counting Sicily or Italy. The British lost 220,000, the Americans about another 20,000.
> 
> ...


I left the British out of my comment and they probably had a hand in dishing out the P40 to Aussie's, Kiwi's, SAAF and such. It definitely got used in Europe but mostly before US got in with better planes. Italy still gets a tough write up where we(USA) were learning to fight uphill with equipment we still learning to fight with.


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## BiffF15 (Jan 17, 2022)

FLYBOYJ said:


> This is about the extent of high G maneuvers I'm willing to deal with these days!
> 
> This was taken about 23 years ago. I used to help the owner with maintenance and his annual condition inspection. This was an FCF where we got the system for the G suits working, so we went and tried it out. I can't remember how many Gs we pulled but it's a little un-nerving seeing those tip tanks flop around when you're yanking and banking!
> 
> View attachment 654919


Were the seat still hot? And if so, what does the civilian world do for mx on them?


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## nuuumannn (Jan 17, 2022)

Thumpalumpacus said:


> There was certainly a need for USA fighters in Europe -- if only for the bombers and nothing else -- in my view.



Definitely. In hindsight it was a hard lesson for the USAAF to learn as the original intent was that the B-17 could operate _unescorted_ over Europe. This was the basis of the British use of the Fortress I in 1941. That little experiment was costly and taught the USAAF and RAF much, but the essential lesson was _not_ learned, that if both the British and US wanted to conduct daylight bombing ops they needed escort fighters. To match the situation because for some bizarre reason certain RAF heads (yes, you, Portal) refused to acknowledge the need for escort fighters, the RAF went to full-time night offensives, although they did fly daylight raids with escorts, no less, into occupied territories. 



gordonm1 said:


> I left the British out of my comment and they probably had a hand in dishing out the P40 to Aussie's, Kiwi's, SAAF and such.



They did. All those services bought the P-40 through the British production orders, their aircraft being delivered with British equipment. It's worth noting that the Brits bought US aircraft before the US had entered the war because they needed aircraft in numbers whose supply was not under attack and could be maintained - that's what mattered. What the Battle of Britain had taught the RAF was that the numbers game applied and the side with the most aircraft being resupplied quickly to replace attrition could, and in the BoB situation, did win. Since US factories were not subject to bombing raids, supply of US aircraft was only natural, but of course was on condition of the US government, hence the establishment of the British (and French) Purchasing Commission.


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## FLYBOYJ (Jan 17, 2022)

BiffF15 said:


> Were the seat still hot? And if so, what does the civilian world do for mx on them?


These seats were hot and at this time this operator was able to get his hands on cartridges that were still within shelf life. Some operators will deactivate the seat or fly with expired cartridges with the hope that "someone" (either the A&P signing off the inspection or FAA) will look the other way. This bird came from Canada and IIRC had older MB seats where you had to physically unbuckle yourself after you punched out.

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## Thumpalumpacus (Jan 17, 2022)

nuuumannn said:


> To match the situation because for some bizarre reason certain RAF heads (yes, you, Portal) refused to acknowledge the need for escort fighters, the RAF went to full-time night offensives, although they did fly daylight raids with escorts, no less, into occupied territories.



I think the RAF's decisions about bombing strategy was rational considering what fighters they had to hand. Leaving aside the lucky break that the Merlin Mustang gave the USAAF, would the RAE have come up with a long-range daylight escort quickly enough to matter? Doubtful -- and the USAAF only got lucky by the pairing of a fine airframe with an import-design engine.

Under those circumstances, the switch to night-bombing makes some sense, especially once the boffins got to work to improve accuracy.

Developing indigenous fighters to escort Lancs on daylight ops would probably be a big ask for the British industry of the time, methinks.

I'm not well-read on the matter so I definitely appreciate any corrections offered. But it seems to me that Brit aircraft production was already pretty stretched.

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## nuuumannn (Jan 17, 2022)

Thumpalumpacus said:


> Leaving aside the lucky break that the Merlin Mustang gave the USAAF, would the RAE have come up with a long-range daylight escort quickly enough to matter? Doubtful -- and the USAAF only got lucky by the pairing of a fine airframe with an import-design engine.



Discussion surrounding escort fighters within the Air Ministry began before the outbreak of war and were raised following analyses of the Spanish Civil War - I'm sure this was not the first mention of it in the between-the-wars RAF either. C-in-C Bomber Command Edgar Ludlow-Hewitt raised the issue in 1938/1939, so it was certainly not solely a wartime discussion point. Development of a long range escort could have been done on existing airframes - there was investigation of the possibility of converting the Spitfire into a long range escort and Supermarine test pilot Jeffrey Quill flew a Spitfire fitted with long range tanks on a cross-country flight that equated to the distance between the UK and Berlin. That the fuel left over was insufficient to enable combat was a notable point, but it did demonstrate that the Spitfire could be ferried across long distances, if not be specially modified as a dedicated long range escort fighter.



Thumpalumpacus said:


> I'm not well-read on the matter so I definitely appreciate any corrections offered. But it seems to me that Brit aircraft production was already pretty stretched.



It was, but where needs must. If the RAF had a requirement for it, it would have happened. The Spitfire is an example where modifications on the production line kept the aircraft current throughout the war in the face of ever-increasing speeds and altitudes, so such a thing was possible, just not acceptable. Chief-of-Air Staff Charles Portal was dead set against escort fighters, that alone is going to hamper any development, rather than production interruption. Griffon engined Spitfires had auxiliary tanks installed to compensate for a higher fuel consumption compared to Merlin engined varieties, so modifying the aircraft _could _have been done _if _there was a desire to do so.

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## Thumpalumpacus (Jan 17, 2022)

Food to chew on. Do you have any easy-to-hand sources where I might do further reading on Portal and his apparent obstinacy?


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## nuuumannn (Jan 17, 2022)

Thumpalumpacus said:


> Do you have any easy-to-hand sources where I might do further reading on Portal and his apparent obstinacy?



The book The Right of the Line by John Terraine is a good starting point on the RAF's wartime history and the author questions Portal's stance against evidence, which is compelling in hindsight.

Amazon product

Bomber Command by Max Hastings talks about Ludlow-Hewitt and mentions his battle to reform the pre-war Bomber Command, including his stance that escort fighters were needed, but doesn't detail Portal's obstinacy on that subject so much, although he is mentioned within on numerous subjects, specifically over his disagreements with Harris.

Amazon product

I have both these in my library. I don't know for certain but I'm sure there is a biography of Portal in print that goes into the issue.

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## Shortround6 (Jan 17, 2022)

Some of what hindered long range British fighters in 1938-39 was the belief that constant speed propellers were closely allied with devil worship, witchcraft, human sacrifice and Scottish cuisine. 

With the crap propellers (fixed pitch or two speed) the planes had long take offs with light fuel loads, poor climb and other performance penalties. By the time this was getting fixed (summer of 19) the British were running behind. 
Even if Portal had been accidentally run over by a bus, several times, it still would have taken time to make the bomber escort work. Perhaps as soon as 1941, but 1942 could have seen escorts at least over western Germany.

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## nuuumannn (Jan 17, 2022)

Shortround6 said:


> Even if Portal had been accidentally run over by a bus, several times, it still would have taken time to make the bomber escort work. Perhaps as soon as 1941, but 1942 could have seen escorts at least over western Germany.



This is certainly true. The British tendency to slap a big bit of log on the front of their fighters in the late 30s certainly hindered their development, even if bombers and fighter prototypes - the Gloster monoplane fighter and the Boulton Paul Defiant for example were fitted from the outset with variable pitch props. The first two-position props were fitted to RAF fighters before the outbreak of war but Britain was still behind in that aspect.

That doesn't mean that had the impetus been there, then such a thing wouldn't have been attempted. Britain had access to VP props. That some members of the RAF stuck to old habits is certainly true and definitely hindered progress, but Britain is certainly not unique in the fighter escort respect; no one else before 1942 had true long range single-seat fighter escorts apart from the Japanese, not even the Americans and the USAAC had the idea of flying its bombers on unescorted daylight raids even after the British warned them against the idea.

It's also worth mentioning that until the USAAF receives B-17Es and Fs, the most numerous bomber in service is the B-18 Bolo, coupled with the P-36 and P-40C and D models means the USAAC is utterly unprepared for combat in Europe before 1942.

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## Schweik (Jan 18, 2022)

They all thought the twin engine heavy fighters would end up being the escorts (if such were needed). But most of those didn't work out. The only one that ever qualified as an escort was the P-38

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## Schweik (Jan 18, 2022)

BiffF15 said:


> You would be surprised how fast the human body can adapt. The F-15 F16 both have 9G limits, and you routinely pull 5-7 without dog fighting. Moving your head around works up until about 7, then you want to make sure it's aligned before going further. Talking, flying, tactics, running the radar, shooting all becomes second nature.
> 
> G tolerance is interesting. Most folks have about a 4G resting, or when they start to experience graying out. Marathoners will have lower, body builder types higher. We did the centrifuge while at Lead In Fighter Training (LIFT) at Holloman AFB. One of the guys in my class had a 6.5G resting tolerance. He had played football for Texas A&M. The techs were all amazed.



Interestingly, several of the top P-40 aces whose interviews I've read, and some other Allied aces I've read about as well, had some kind of sports background that contributed to a high G tolerance. Nicky Barr, a 10 victory Australian Kittyhawk Ace had been a rugby player and a boxer, and he attributed this to being able to tolerate high G turns. This is one of his comments:

_"I would evade being shot at accurately by pulling so much g-force...that you could feel the blood leaving the head and coming down over your eyes... And you would fly like that for as long as you could, knowing that if anyone was trying to get on your tail they were going through the same bleary vision that you had and you might get away....I had deliberately decided that any deficiency the Kittyhawk had was offset by aggression. And I'd done a little bit of boxing – I beat much better opponents simply by going for [them]. And I decided to use that in the air. And it paid off."_

Reading between the lines a little, one of the Kittyhawks advantages was, assuming you pulled the stick hard enough, it could out turn most of the Axis fighters and even in some cases, Japanese fighters (at high speed). So high G turns were part of a survival strategy. A lot of these pilots had so little training on type that they didn't know this was the case until they tried it out. Clive Caldwell made a point of forcing new pilots to go through some high G turns to prove to themselves that the aircraft (and they as pilot) could endure them.

Greg Boyington had been a fairly serious collegiate wrestler and he credited that. Both talked about bearing down and tightening their neck so they wouldn't pass out.

As you no doubt know most WW2 fighters could manage 5-6 G turns, but the pilots being in upright seats without G suits, they routinely passed out during such maneuvers. Being asleep while going 250 mph with enemy aircraft are around (not to mention the ground) is not so conducive to survival. But it's amazing how often and routinely a lot of pilots seem to have gone through that. Dive bomber pilots often passed out during pull out too, if only for a moment.

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## nuuumannn (Jan 18, 2022)

Schweik said:


> They all thought the twin engine heavy fighters would end up being the escorts



Yes, that's entirely circumstantial of course, the single-seat fighter was believed to not have sufficient range for bomber escort, even though during the Spanish Civil War both sides employed whatever single-seaters they had for bomber escort duties, and the Luftwaffe certainly had the right idea employing Bf 109s over Britain escorting its bombers, which were far more proficient than the Bf 110 Zerstorer in the role, the latter being conceived as a long range fighter/reconnaissance/light bomber.

Perception changes with experience and the Japanese, of all people were the first to employ long range fighters off the bat, which no one else was doing at the time, because of the ranges their aircraft needed to cover traversing their territory in China and the Korean peninsula, before their entry into WW2.

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## nuuumannn (Jan 18, 2022)

Schweik said:


> nterestingly, several of the top P-40 aces whose interviews I've read, and some other Allied aces I've read about as well, had some kind of sports background that contributed to a high G tolerance.



Most of the Kiwi fighter pilots were farmers that dabbled in playing rugby, so being an outdoorsy type was an advantage. Fisken, the highest scoring RNZAF P-40 ace was a farmer.

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## Schweik (Jan 18, 2022)

nuuumannn said:


> It's also worth mentioning that until the USAAF receives B-17Es and Fs, the most numerous bomber in service is the B-18 Bolo, coupled with the P-36 and P-40C and D models means the USAAC is utterly unprepared for combat in Europe before 1942.



While that may be partially true for aircraft already in the existing units, the US were _producing _a lot of aircraft which probably were ready for combat in Europe - many of which were ordered by the French and ended up being used by the British, mostly before 1942 and a few just in the early part of that year. And quite a few of the aircraft already deployed were quite capable.

These include the P-36 which you mentioned, which for all it's flaws turned out to be the most effective Allied fighter in the Battle of France (I believe Hawk-75 units even did better than Hurricane units); the P-40D and E which were in use by the British in 1941 and became their main air superiority fighter in the Med in early 1942; the DB-7/ Boston / A-20 series of bombers, which being capable of 340 mph was one of the fastest bombers in the world in 1941, which also did well for the French and became one of the primary bomber types for the British in North Africa; the Martin 167 Maryland (available in 1940), another fast (300 mph) bomber which did very well for the French in the Battle of France (with an unusually low 4% loss rate), and was again put into heavy use by the British (South Africans) as a bomber in the Western Desert, and (mainly as a recon plane) from Malta, from where it was used to conduct the recon flight before the famous raid on Taranto; the Martin 187 Baltimore another fast bomber and a bit more capable (better armed & with heavier bomb load) than the Maryland, which showed up in early 1942 (but already at the OTU's in 1941); the Lockheed Hudson and (later in 1942) Ventura, which proved their merit mainly in the maritime role, though I'd say as a day-time bomber certainly the Venture and even the Hudson compared pretty well to most other bombers of that vintage.

The P-36 and early P-40 variants lacked the altitude performance to dominate Bf 109s and were not as effective as Spitfire Vs, but they did much better than Hurricanes (including the II variants) in North Africa, and they did much better than most Soviet fighters in 1941 and early 42 on the Russian Front. They also held their own in the Pacific and in China. The three main US bomber types used by the British in North Africa - Boston, Maryland and Baltimore, were _far_ superior to any extant British bombers in terms of surviving combat missions, if not bomb load, and thus were able to operate against the enemy during daytime. The early DB-7 series had very short range (it's main flaw) but this was substantially improved with each new variant. I would say those three bomber types were undoubtedly in the top 5 for Tactical bombers in the world in 1941, rivaled only by the Ju-88, G4M, and Pe-2*. They would be exceeded only by the Mosquito.

I would also say that US Navy aircraft already deployed in 1941, notably F4F-3 (first used in combat at Wake Island in Dec 1941), SBD-3 (first combat action in Dec 1941, sinking the Japanese sub I-70), and TBF Avenger which came later in 1942, were certainly world class in their respective niches. The F4F-3 was I think hands down the best Allied naval fighter in 1941 or 1942, and was only rivaled by the Zero. The SBD was certainly the best dive bomber available and far exceeded the Skua etc.. I would say the same about the TBF, though the earlier TBD was probably inferior to a Swordfish.

Finally, the B-24 Liberator was delivered to it's first units in 1941. This aircraft was fast, flew high, was well armed and carried a fairly heavy bomb load out to a long range. It proved to be quite capable both as a daytime Operational bomber (notably in North Africa after Torch, used against Axis airfields) and of course, played it's role in the Strategic bombing. It was also extremely useful in the Maritime role as we know.

*By contrast, I don't think the Blenheim, the main British tactical bomber at that time, was in the running.


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## Schweik (Jan 18, 2022)

nuuumannn said:


> Most of the Kiwi fighter pilots were farmers that dabbled in playing rugby, so being an outdoorsy type was an advantage. Fisken, the highest scoring RNZAF P-40 ace was a farmer.



It shows some of the hidden advantages of martial arts and war-like sports for soldiers, even in the modern era.


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## nuuumannn (Jan 18, 2022)

Schweik said:


> While that may be partially true for aircraft already in the existing units, the US were _producing _a lot of aircraft which probably were ready for combat in Europe - many of which were ordered by the French and ended up being used by the British, mostly before 1942 and a few just in the early part of that year. And quite a few of the aircraft already deployed were quite capable.




Only for the British and French though. Before the British and French Purchasing Commissions, the US military machine was not geared up for mass production on the same scale that it eventually became. The US certainly didn't hit the ground running. It took time and the impetus of war in Europe for firms to get to a production standard that we are familiar with in common perception. It took Boeing a year to build around 40 B-17s, for example.

US aircraft were by and large good aircraft, but warfare was changing and many failed to make the cut, aircraft such as the Vought Chesapeake and Bell Airacobra were deemed unsuitable for British needs and it is interesting that in 1939, apart from the Catalina for Britain and Hawk 75 and DB-7 for France, the aircraft that saw the largest usage by the British and French were aircraft designed specifically for British orders, such as the Lockheed Hudson and Martin 167.

About the Hawk 75, yes, the British tested it in January 1940 and praised it, noting that it was more manoeuvrable than the Spitfire and Hurricane and had lighter controls, the pilot found it exceptionally easy and pleasant to fly, it had docile stall characteristics, but an order was not forthcoming as it couldn't match the Spitfire's performance and altitude. The Mohawks the RAF received were ex-French order aircraft that had to be modified from French standard, such as reverse working power levers, pull back for power instead of the more familiar Balls-to-the-wall, for example. 

The Tomahawk/Kittyhawk was also praised for its handling and behaviour but again, its performance was lacking compared to the Spitfire. In the Kittyhawk I the test pilots praised it as having the best gunnery characteristics of US fighters they had tested. The Kittyhawk and Tomahawk were ordered in large numbers through the British Purchasing Commission as we know.

It is worth noting that between the Spitfire and Bf 109, European air forces had the best fighters in the world at the time, at the outbreak of the war the Bf 109 Emil edged out the Spitfire Mk.I and could arguably be described as _the_ best fighter in the world.

Yes, the B-24, or LB-30 was a good long range aircraft, but it had poor defensive armament and it is worth noting that the first Liberator variant armed with power turrets was the British only Liberator Mk.II that was fitted with Boulton Paul turrets. The USA didn't have production gun turrets until the British supplied US firms with technology. Examples of turrets went to the USA and the likes of Sperry, Emerson and Martin benefitted from British expertise in this field.

My point in mentioning these things is to put British aircraft and decision making into context. The British found themselves in a war they were not prepared for. Some things they got right, some they got wrong, but the reality was that there was no other air force that could have done any better than what the British did between 1939 and late 1941. British bombers were among the best and most capable in the world at the time compared to their contemporaries yet there is much criticism of the likes of the Whitley and Wellington for example, yet the Whitley V in service in 1939 was faster than, had a greater bomb load and could carry it over a greater distance and was better defended than the USAAC's standard bomber the B-18. The USAAC/F was armed with less capable aircraft and had no modern combat experience compared to what was going on in Europe.

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## Schweik (Jan 18, 2022)

nuuumannn said:


> Only for the British and French though. Before the British and French Purchasing Commissions, the US military machine was not geared up for mass production on the same scale that it eventually became. The US certainly didn't hit the ground running. It took time and the impetus of war in Europe for firms to get to a production standard that we are familiar with in common perception. It took Boeing a year to build around 40 B-17s, for example.


None of the Allies were really ready for the war. Britain got into it earlier but was also in a steep learning curve, not just with constant speed propellers but also things like assembly-line production standards (as opposed to 'bespoke'), self sealing fuel tanks, fuel capacity, fighter and bomber tactics etc.



nuuumannn said:


> US aircraft were by and large good aircraft, but warfare was changing and many failed to make the cut, aircraft such as the Vought Chesapeake and Bell Airacobra were deemed unsuitable for British needs and it is interesting that in 1939, apart from the Catalina for Britain and Hawk 75 and DB-7 for France, the aircraft that saw the largest usage by the British and French were aircraft designed specifically for British orders, such as the Lockheed Hudson and Martin 167.



Martin 167 was I believe for a French order, which the British took over. Same for the 187 which was a much more important bomber for the British.



nuuumannn said:


> About the Hawk 75, yes, the British tested it in January 1940 and praised it, noting that it was more manoeuvrable than the Spitfire and Hurricane and had lighter controls, the pilot found it exceptionally easy and pleasant to fly, it had docile stall characteristics, but an order was not forthcoming as it couldn't match the Spitfire's performance and altitude. The Mohawks the RAF received were ex-French order aircraft that had to be modified from French standard, such as reverse working power levers, pull back for power instead of the more familiar Balls-to-the-wall, for example.


Yes I'm aware. But those same Hawk 75s held their own quite well against the Bf 109 and Bf 110 in the Battle of France.



nuuumannn said:


> The Tomahawk/Kittyhawk was also praised for its handling and behaviour but again, its performance was lacking compared to the Spitfire. In the Kittyhawk I the test pilots praised it as having the best gunnery characteristics of US fighters they had tested. The Kittyhawk and Tomahawk were ordered in large numbers through the British Purchasing Commission as we know.
> 
> It is worth noting that between the Spitfire and Bf 109, European air forces had the best fighters in the world at the time, at the outbreak of the war the Bf 109 Emil edged out the Spitfire Mk.I and could arguably be described as _the_ best fighter in the world.



In many ways, perhaps that is true, but it also had some limitations - especially range. The Emil was the first 109 variant being used in the Western Desert in 1941 and due to problems (losses) in combat with Tomahawks they rushed it's replacement with the 109F.



nuuumannn said:


> Yes, the B-24, or LB-30 was a good long range aircraft, but it had poor defensive armament and it is worth noting that the first Liberator variant armed with power turrets was the British only Liberator Mk.II that was fitted with Boulton Paul turrets. The USA didn't have production gun turrets until the British supplied US firms with technology. Examples of turrets went to the USA and the likes of Sperry, Emerson and Martin benefitted from British expertise in this field.
> 
> My point in mentioning these things is to put British aircraft and decision making into context. The British found themselves in a war they were not prepared for. Some things they got right, some they got wrong, but the reality was that there was no other air force that could have done any better than what the British did between 1939 and late 1941. British bombers were among the best and most capable in the world at the time compared to their contemporaries yet there is much criticism of the likes of the Whitley and Wellington for example, yet the Whitley V in service in 1939 was faster than, had a greater bomb load and could carry it over a greater distance and was better defended than the USAAC's standard bomber the B-18. The USAAC/F was armed with less capable aircraft and had no modern combat experience compared to what was going on in Europe.











1933 Martin B-10 left, 1934 Handley Page Heyford right

The first modern bomber aircraft in the 30's to really turn heads was arguably the incredibly ugly but rather fast (for the time) Martin B-10 of 1933, and it was partly on the strength of the performance of that aircraft that the French put in those large orders for Martin 167s.

The Whitley (230 mph) may have seemed impressive for a moment, but it did not prove capable of enduring combat where enemy fighters might be about. Same for the somewhat more ambitious but still slow (247 mph) and lightly armed Hampden. The less said about the Harrow or the Bombay the better. The Wellington was a much better design and retained a niche through the war, but was still very slow (235 mph) and was rarely used in daylight tactical strikes (even though it was available in North Africa). The Blenheim of course was serviceable and was used as a tactical bomber, but suffered appalling losses for little gain. The Beaufort proved fairly effective in the maritime strike role.

But compared to these, the Boston, Maryland and Baltimore were a generation ahead in terms of facing the dangers of modern war in 1941-42. Far superior.

The B-24 may have benefited from some British technology, (I don't know the history of the turret development) but regardless, it proved to be a highly capable design which was used effectively against the enemy through the end of the war, which is not something you can say for the Hampden, Whitley, Bombay, or Harrow. Same for the B-17, which was already active in 1941. It needed a lot more improvement but it already had a role, and just became more and more effective as the war went on (regardless of what you think of the Strategic Bombing Campaign, of which I am a skeptic).

The P-36 proved capable against German fighters in France, and the P40C/D/E models were considered (by the British) better than the Hurricane and though inferior to the Spitfire V, not so much so that they couldn't face Bf 109s. They were at least on par with the best Russian, Italian and Japanese planes of 1941. That puts US military aircraft roughly on par with the rest of the world I'd say overall. The US had better bombers and slightly inferior fighters to the British and the Germans. Maybe you could say the Japanese too. They were probably a bit better than the Soviet and Italian aircraft of that time.

And as good as the Spitfire was it had some serious flaws, especially it's range. Same was true for the 109 of course. In the Western Desert tactics and training were the main difference IMO.

As I previously mentioned, the US Navy F4F and SBD of course proved extremely capable and were the best naval fighter and strike aircraft available to the Allies in 1941. The F4F was slightly inferior to the Japanese Zero but the SBD was arguably superior to the D3A.

Yes the US had the P-39, Buffalo, TBD Devastator, Vought Vindicator, and Brewster Buccaneer ... but the British had the Battle, the Skua, the Fulmar, the Defiant, the Roc, etc. i.e. all nations in WW2 had some dud designs and some yeoman designs, and a few wild successes.

You are right that in many ways, the US was ill-prepared for War. I think that is true of all the Allies because in the wake of the horrors of WW I, nobody really thought the Axis powers would fling themselves into a new massive conflict so soon, and many of the leadership in the US had convinced themselves that they would stay out of it. The aircraft on-hand however were actually pretty good. The US also had a thriving and quite sophisticated civilian aircraft industry which proved readily adaptable to military purposes.

It's also true that many of the best designs had been somewhat ignored by the USAAC and were actually selected for production by the French, and later the British, but these aircraft were on-hand and the War Dept knew they were available. For example they had put in a small order the Boston to keep the design alive. For this reason, and because of clearly (for their time) very good aircraft like the F4F, SBD, P-40, A-20, B-17 and B-24 I would say that the claim that "_the USAAC is utterly unprepared for combat in Europe before 1942._" is rather exaggerated.

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## nuuumannn (Jan 18, 2022)

Schweik said:


> You are right that in many ways, the US was ill-prepared for War. I think that is true of all the Allies because in the wake of the horrors of WW I, nobody really thought the Axis powers would fling themselves into a new massive conflict so soon, and many of the leadership in the US had convinced themselves that they would stay out of it. The aircraft on-hand however were actually pretty good. The US also had a thriving and quite sophisticated civilian aircraft industry which proved readily adaptable to military purposes.



This is very true and I won't pick on each of the points you made regarding individual aircraft as I'm sure your research is good and others will pick at it if they find flaws, but suffice to say, context is the key to comparing individual aircraft. Some were better than others at one thing or another, but placing these aircraft in the context of how they were used at the time, rather than looking at them with loaded perceptions as we do changes how we see them, for example, my comment about the Bf 109 is accurate _in context_. The Bf 109 was the best fighter in the world not because of its individual characteristics - it had awkward undercarriage that caused ground loops, it couldn't manoeuvre with dog fighters, it had poor range etc, but put it against the backdrop of what the Nazis used it for in the first couple of years of war and it reigns supreme.

The Blackburn Skua, even the Air Ministry believed it was bordering on being obsolete when it first entered service in 1937, but put it against a German light cruiser in a harbour in Norway and you have a deadly ship-killing machine.

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## Shortround6 (Jan 18, 2022)

Without the distractions and as actually built you had the P-40s starting to arrive in May of 1940 at the Factory. All 11 of them. 

The US had placed the over 500 order in April of 1939. 
The US allowed the French thus the British to "jump the queue" First French aircraft flew in June of 1940. The French had ordered 230 P-40s in October of 1939. 
The first 100 Tomahawks got the British got (starting Sept of 1940) from the French (with French instruments and the reverse throttles) were mostly used as trainer and even a few instructional airframes as the British didn't think they were combat worthy. They did not have self sealing tanks or armor or BP glass.
The US took a lot of their over 500 P-40s from the first order in dribs and drabs so it certainly looks, if you look at the numbers delivered, as if the US was very slow when preparing for war. Curtiss built 481 H75/P-36s in 1940 and 778 P-40s in 1940. The US only took 200 P-40s in 1940 and in fact didn't take any P-40Bs until March of 1941. The last of the original order was completed May 20th 1941. Please note that another 773 P-40s were built from Jan through May of 1941. 
Some of the early P-40s were NOT up world standards, but of course world standards were changing every few months. 

How many versions of DB601s did the 109E go through? 
Changes to armor or protection? 
Changes to the armament? 

What were the world standards for the French fighters?
Or Russian.
In 1940 the Bulk of the Japanese fighters had fixed landing gear. 

The Germans did well, in part, because they figured out the "fingers four" a lot sooner that just about anybody else did.

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## nuuumannn (Jan 18, 2022)

Shortround6 said:


> In 1940 the Bulk of the Japanese fighters had fixed landing gear.
> 
> The Germans did well, in part, because they figured out the "fingers four" a lot sooner that just about anybody else did.



This is the point. The context within which each operated.

The US manufacturers identified that building for foreign needs kept them in business because the US military simply wasn't ordering in nearly as large numbers as foreigners were before the US entered the war. Why wouldn't they? Before the BPC ordered Hudsons from Lockheed, how many military aircraft was that firm building? What was its production rate? Look at how many US types the Brits and French investigated and ordered; manufacturers were falling over themselves for contracts and understandably so. Many of the aircraft were unsuited for the European conditions, but that didn't mean the Brits and French weren't about to take them and test them. Even the woeful Curtiss Sea Mew was evaluated in Britain for service.

Despite the Japanese aircraft having fixed landing gear, how effective in theatre were they? Very, in fact. The Ki-27 and A5M were formidable fighters against the opposition they were expecting and the Germans figuring out the Finger Four again highlights the context within the environment the Bf 109 was operating. The Germans figured their tactics out in Spain and that conflict prepared them for what they were about to embark on.

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## wuzak (Jan 18, 2022)

Schweik said:


> And as good as the Spitfire was it had some serious flaws, especially it's range. Same was true for the 109 of course. In the Western Desert tactics and training were the main difference IMO.



The P-40 wasn't exactly a long range champion!


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## Schweik (Jan 18, 2022)

Shortround6 said:


> The Germans did well, in part, because they figured out the "fingers four" a lot sooner that just about anybody else did.



I think THIS. The Germans were expecting the war to happen when it did, because they started it. Their core cadre of pilots were very well trained, some bloodied in the Spanish Civil War, and they were using finger four and other sophisticated tactics they had carefully worked out. They had radios in their aircraft (that worked) and fought in a disciplined manner led by veteran pilots.

Meanwhile I don't know about England but I know US and Australian pilots were so new to their P-40s in late 1941 and early 1942 they were crashing in about 20% of their landings. They weren't used to 1,000 hp engines or retractable landing gear. The Allies were scrambling to get everyone trained and to develop suitable tactics, which took a while to disseminate. 

Was the Emil really better than a Spitfire? In several ways it was more sophisticated, it had fuel injection and leading edge slats, combat flaps and a hydromatic / barometric controlled supercharger. But the Spitfire was so beautifully streamlined in spite of having 4' wider wingspan and a 40% greater wing area (with resulting superiority in turn performance) was actually faster than the Emil. I think the Spit I and the Emil were roughly equivalent. Which was better Spit or 109 went back and forth through the war with all the different variants, but they were always pretty close.

The Japanese similarly had a big early advantage because so many of their pilots had combat experience in China and because they had worked out the optimal tactics for their aircraft. And yes their aircraft were excellent. But we all here know that aircraft, especially fighter design is a bit of a paper / scissors / rock thing. You gain one advantage at the expense of another. Bf 109 wasn't perfect, neither was the Zero. A lof of their early successes can be chalked up (IMO to being more prepared for war in the early part of it, and this flip flopped and Allied training swiftly caught up, and Axis pilots suffered from attrition. As we know.

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## pbehn (Jan 18, 2022)

Schweik said:


> Meanwhile I don't know about England but I know US and Australian pilots were so new to their P-40s in late 1941 and early 1942 they were crashing in about 20% of their landings. They weren't used to 1,000 hp engines or retractable landing gear. The Allies were scrambling to get everyone trained and to develop suitable tactics, which took a while to disseminate.


What did Australians train in to be unused to 1000HP engines and fixed U/C? How did their training differ from other RAF units? I thought the majority converted from Hurricanes.


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## Schweik (Jan 18, 2022)

wuzak said:


> The P-40 wasn't exactly a long range champion!



It was a medium range fighter. Which is to say, it seems to have had about twice the effective range of a Spit V, 109E or F, of MC 202. Or most of the Soviet fighters.

The relevance in the Med was that the Spitfires were almost always used for point defense and rarely for escorting strikes, except when they were really close to the base.


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## Schweik (Jan 18, 2022)

pbehn said:


> What did Australians train in to be unused to 1000HP engines and fixed U/C? How did their training differ from other RAF units?



I have no idea, I am just referring to what happened when the Australian 75th FS were flying their new P-40s across Australia, from the South to Darwin. Two of the issues they mentioned was engine torque and retractable landing gear. They made about 6 hops and lost about 2/3 of their fighters in the process. Same thing happened to the 49th FG on their way up, and then again to the RAAF 74th FS. Some of the aircraft were later repaired and flown up.


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## wuzak (Jan 18, 2022)

Schweik said:


> In many ways, perhaps that is true, but it also had some limitations - especially range. The Emil was the first 109 variant being used in the Western Desert in 1941 and due to problems (losses) in combat with Tomahawks they rushed it's replacement with the 109F.



It is instructive to know how important that the northern desert campaign was for the RAF and Luftwaffe to see what aircraft they did and did not use.

The RAF used the Tomahawk II and Hurricane II, but did not, initially, use Spitfires, of any mark, in theatre.

The Luftwaffe initially used the Bf 109E, though the Bf 109F had entered service nearly a year before Tomahawks show up in North Africa. The Bf 109F-4 had entered Luftwaffe service in July 1941. The Bf 109G-1 started production in early 1942.

The Focke Wulf Fw 190 did not appear in North Africa for more than a year after its debut in Europe,


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## pbehn (Jan 18, 2022)

Schweik said:


> I have no idea, I am just referring to what happened when the Australian 75th FS were flying their new P-40s across Australia, from the South to Darwin. Two of the issues they mentioned was engine torque and retractable landing gear. They made about 6 hops and lost about 2/3 of their fighters in the process. Same thing happened to the 49th FG on their way up, and then again to the RAAF 74th FS. Some of the aircraft were later repaired and flown up.


I thought you were discussing N Africa. That is just lack of training.


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## Schweik (Jan 18, 2022)

nuuumannn said:


> This is the point. The context within which each operated.
> 
> The US manufacturers identified that building for foreign needs kept them in business because the US military simply wasn't ordering in nearly as large numbers as foreigners were before the US entered the war. Why wouldn't they? Before the BPC ordered Hudsons from Lockheed, how many military aircraft was that firm building? What was its production rate? Look at how many US types the Brits and French investigated and ordered; manufacturers were falling over themselves for contracts and understandably so. Many of the aircraft were unsuited for the European conditions, but that didn't mean the Brits and French weren't about to take them and test them. Even the woeful Curtiss Sea Mew was evaluated in Britain for service.



The US top leadership (i.e. FDR, George Marshall) knew that the US was probably going to end up fighting the Germans and would be allied with England and France. They also knew England and France were going to be fighting sooner. So it made sense to give priority to these soon to be Allied nations for the early ramp up in military aircraft production, which is something they did quite deliberately. Thus conferring upon the French and the British their best attack bombers etc.



nuuumannn said:


> Despite the Japanese aircraft having fixed landing gear, how effective in theatre were they? Very, in fact. The Ki-27 and A5M were formidable fighters against the opposition they were expecting and the Germans figuring out the Finger Four again highlights the context within the environment the Bf 109 was operating.


They were, though they suffered at the hands of P-40s in China



nuuumannn said:


> The Germans figured their tactics out in Spain and that conflict prepared them for what they were about to embark on.



Partly because they knew they were going to start the war, while some of the Allied leadership was still hoping they could prevent it.

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## Schweik (Jan 18, 2022)

pbehn said:


> I thought you were discussing N Africa. That is just lack of training.



They had a lot of problems in N. Africa too. According to squadron leaders like Billy Drake, Clive Caldwell, Eddie Edwards, Bobby Gibbes etc., the British / Commonwealth pilots there had basically zero gunnery training (until Caldwell invented some system of shooting at shadows) and had almost no combat training in North Africa in the early years.


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## Schweik (Jan 18, 2022)

wuzak said:


> It is instructive to know how important that the northern desert campaign was for the RAF and Luftwaffe to see what aircraft they did and did not use.
> 
> The RAF used the Tomahawk II and Hurricane II, but did not, initially, use Spitfires, of any mark, in theatre.
> 
> ...



Actually the war started with the Italians using CR 32s against British Gladiators (plus Lysanders and various other oddball crates), which were about evenly matched. Then the British sent in Hurricanes and the Italians Cr 42s and a few MC 200s, but the Hurricanes had the better of it. So the Germans initially sent in Bf 110s, which were not good enough. Then the Germans sent JG.27 with the 109E, which swung the balance back in their favor, and the British sent Tomahawks in fall of 1941. J.G. 27 was still dominating the British but after a couple of rough days the Germans brought in the 109F-2, the British sent Kittyhawks, then the Italians started sending more and more MC 202s, and then the Spitfires came in mid 1942. The US came with P-40Fs and P-38s, and then the Germans sent F-4s and G-2s, and some Fw 190s, and brought in some more squadrons of Bf 109s (JG 77 and part of 53) as J.G 27 was finally broken.

So it was, IMO, more of a tit for tat which gradually escalated both in the scale and quality of the aircraft.

However, while it's true that neither side sent their very best fighters at first, that doesn't mean it was an unimportant Theater. The importance ramped up from a backwater to a raging full scale war. The British having suffered a 'near thing' at the Battle of Britain, hoarded their Spitfires for a while, but eventually they started deploying them because the threat to the Suez etc. was getting very real. The Germans were already facing a mounting emergency in Russia, even before Stalingrad - which felt more existential. The Russians would eventually be in Berlin after all. But they saw an opportunity to choke off British lines of communication to India etc. so they made a serious effort.

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## Shortround6 (Jan 18, 2022)

Well, the world standard was certainly varied 

The Hawk 75 is supposed to be the best the French could get.

I haven't compared training times or time in service.
However the Hawk 75 and the P-36 were both noted for structural weaknesses, one reason the P-40 may have porked up? 
There was a French officer running around Buffalo trying to by 30 wing sets in Dec 1939/Jan 1940 as they had about 30 planes grounded because they had no spare wings.
The French had purchased (in money value) the equivalent of 50 airframes for 200 complete aircraft.
Reasons looked into were damage due to gun fire, wing failures due to high stresses at poor wartime airdromes and a high rate of landing accidents, plus an insufficient order for spare parts.
It does make you wonder what the rest of the French fighters were like?

While the maneuverability of the Hawk 75 is often mentioned against the Spitfire what is often left out is that the Spitfire could enter or break off combat at will due it's superior speed. The test Spitfire was number K9944 was one of the first 215 or so flown and while it is highly doubt it had a fixed pitch prop it is very likely it used a two pitch prop while the Hawk had a constant speed prop. The constant speed prop reduced the climb 20,000ft from 11.3 minutes to 7.7 minutes.

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## Thumpalumpacus (Jan 18, 2022)

nuuumannn said:


> The book The Right of the Line by John Terraine is a good starting point on the RAF's wartime history and the author questions Portal's stance against evidence, which is compelling in hindsight.
> 
> Amazon product
> 
> ...




Thanks for the leads, I'm bookmarking this post to add to the shopping list once I catch up on current reading.

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## Schweik (Jan 18, 2022)

Shortround6 said:


> Well, the world standard was certainly varied
> 
> The Hawk 75 is supposed to be the best the French could get.
> 
> ...



I suspect the D.520 was actually the best fighter the French had, they just had so little time to get used to it before the battle started, and relatively few of them were even out with their units and so on. D.520 was considerably faster than the Hawk 75, much better armed (with a 20mm HS.404) and being smaller, inline engined and nicely streamlined probably kept up a better combat speed. The D.520 had armor and a self sealing fuel tank too. I think the Hawk maybe had some armor?

The French didn't seem to have any complaints about the sturdiness of the Hawk 75 during the BoF though, to the contrary, they said it was a beast. They also did pretty well with it against the US Navy during Torch as I pointed out before (actually with both the Hawk 75 and the D.520).


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## nuuumannn (Jan 18, 2022)

Schweik said:


> I suspect the D.520 was actually the best fighter the French had, they just had so little time to get used to it before the battle started, and relatively few of them were even out with their units and so on.



It was, but it was a lot more difficult to fly and train on, the Hawk 75 was praised because of its ease of handling. The MS.406 was the most numerous French fighter at the time of the German invasion.


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## Shortround6 (Jan 18, 2022)

Schweik said:


> It was a medium range fighter. Which is to say, it seems to have had about twice the effective range of a Spit V, 109E or F, of MC 202. Or most of the Soviet fighters.
> 
> The relevance in the Med was that the Spitfires were almost always used for point defense and rarely for escorting strikes, except when they were really close to the base.



It does help to figure how they were really using it. 
The gross weight usually listed for was with 120 US gallons of fuel.
They could put 160 US gallon into a P-40B or early Tomahawk. The later ones got about 135 US gallons but could be fitted with the drop tank. 

But then you have to figure the performance loss (climb and turn) for the extra fuel/oil load.


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## Jabberwocky (Jan 18, 2022)

Schweik said:


> p0-+edI have no idea, I am* just referring to what happened when the Australian 75th FS were flying their new P-40s across Australia, from the South to Darwin. Two of the issues they mentioned was engine torque and retractable landing gear. They made about 6 hops and lost about 2/3 of their fighters in the process. Same thing happened to the 49th FG on their way up, and then again to the RAAF 74th FS. Some of the aircraft were later repaired and flown up.



The RAAF pranged a lot of Spitfires around Darwin as well. 

Anthony Cooper's _Darwin Spitfires_ book gives 36 Spitfire VCs damaged badly enough during takeoff or landing between February and September 1943 to require attention from the Repair and Servicing unit. He attributes this to the conditions inherent to the bush airfields the Spitfires were operating from. These were narrow and made of dirt (compared to the wide grassy airfields used by in the UK and in NSW). Of the 36 Spitfires, only seven (~20%) were actually damaged at the main paved Darwin airfield, the rest were damaged at the smaller ancillary dirt fields.

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## nuuumannn (Jan 18, 2022)

Schweik said:


> They were, though they suffered at the hands of P-40s in China



The number of P-40s in theatre at the time was small by comparison however and they weren't at that time everywhere the Japanese were going. The Ki-27 was used against the Soviet Union, whose fighters were more of the type the Japanese were expected to encounter. The problem is that believing that fixed undercarriage is behind the times doesn't equate to the status quo at the time and as we know, at the time the Ki-43 and A6M were undergoing development; fully modern and in the case of the A6M, the best and most modern aircraft carrier fighter of the age.



Schweik said:


> The US top leadership (i.e. FDR, George Marshall) knew that the US was probably going to end up fighting the Germans and would be allied with England and France. They also knew England and France were going to be fighting sooner. So it made sense to give priority to these soon to be Allied nations for the early ramp up in military aircraft production, which is something they did quite deliberately. Thus conferring upon the French and the British their best attack bombers etc.



True, but politics enters the fray and frowns upon the USA from overtly supporting the Allied war effort. The US was, at the time, as it is today politically divided, over the war. Needless to say though, FDR was very keen on providing the Allies military hardware.



Schweik said:


> Partly because they knew they were going to start the war, while some of the Allied leadership was still hoping they could prevent it.



Obviously. Fully because their intentions were to make war in Western Europe despite the machinations of other European leaders.

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## Schweik (Jan 18, 2022)

Shortround6 said:


> It does help to figure how they were really using it.
> The gross weight usually listed for was with 120 US gallons of fuel.
> They could put 160 US gallon into a P-40B or early Tomahawk. The later ones got about 135 US gallons but could be fitted with the drop tank.
> 
> But then you have to figure the performance loss (climb and turn) for the extra fuel/oil load.


All of that is true for every longer ranged fighter; P-51Ds didn't handle so well with a full load of fuel either. The idea was that they usually encountered enemy fighters near or over the target area, by which time they had burned off most of the less conveniently located (as in in external or overload tanks) fuel while taking off, climbing up to altitude, and flying to the target. If they were jumped early on a strike when they had drop tanks they sometimes had to jettison the tanks and abort the mission in order to defend themselves. 
I thought the P-40B couldn't take a drop tank, but the P-40C could. I may be remembering wrong.
Didn't the Spitfire have an unprotected or lightly protected (i.e. no self sealing) fuel tank in front of the pilot?


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## Shortround6 (Jan 18, 2022)

Schweik said:


> I suspect the D.520 was actually the best fighter the French had, they just had so little time to get used to it before the battle started, and relatively few of them were even out with their units and so on. D.520 was considerably faster than the Hawk 75, much better armed (with a 20mm HS.404) and being smaller, inline engined and nicely streamlined probably kept up a better combat speed. The D.520 had armor and a self sealing fuel tank too. I think the Hawk maybe had some armor?
> 
> The French didn't seem to have any complaints about the sturdiness of the Hawk 75 during the BoF though, to the contrary, they said it was a beast. They also did pretty well with it against the US Navy during Torch as I pointed out before (actually with both the Hawk 75 and the D.520).


Well, they were having trouble with the wings, and they broke at least one (some stories say several) when they tried to do acrobatics with the behind the seat tank filled. That was more of a too far aft CG thing.

Problem is that the active French campaign was so short and chaotic that that reports more than losses are hard to come by, like maintenance problems.

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## Schweik (Jan 18, 2022)

nuuumannn said:


> It was, but it was a lot more difficult to fly and train on, the Hawk 75 was praised because of its ease of handling. The MS.406 was the most numerous French fighter at the time of the German invasion.



Yes. MS 406 was a 30's era fighter whose time had come and gone. And lets not forget the Bloch 150 / 152 series, which seems to have been a dud.

But it's not really clear because the Bloch 150 series, like so many French planes, really never had a proper work up / shakeout before the war started. Many of them were not even fully equipped (with radios, all their guns, instruments etc.) before they went into combat.

Same for the D.520. They just got to the units and were just starting to learn to fly them when the fighting really started. Whereas IIRC there were several French squadrons which had already been flying the Hawk 75s a few months (?) before the fighting started. I don't remember the exact dates but I know they had more time on it. The French also had some other promising types just coming out like the VG 33 / 35 series and some interesting attack planes like the Breguet 693 which might have done a lot better if they had time to get them worked up and maybe tweak the tactics a little.

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## Shortround6 (Jan 18, 2022)

Schweik said:


> All of that is true for every longer ranged fighter; P-51Ds didn't handle so well with a full load of fuel either. The idea was that they usually encountered enemy fighters near or over the target area, by which time they had burned off most of the less conveniently located (as in in external or overload tanks) fuel while taking off, climbing up to altitude, and flying to the target. If they were jumped early on a strike when they had drop tanks they sometimes had to jettison the tanks and abort the mission in order to defend themselves.
> I thought the P-40B couldn't take a drop tank, but the P-40C could. I may be remembering wrong.
> Didn't the Spitfire have an unprotected or lightly protected (i.e. no self sealing) fuel tank in front of the pilot?


Point is you can you have the extra fuel or you can have the weight penalty. 
If the Germans are operating at less than a full load they have the advantage. 
If your Hurricane is operating at, say 50% full (combat then getting home) then a P-40 isn't going to have much more fuel or it is going to be carrying more weight.


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## Thumpalumpacus (Jan 18, 2022)

I just want to say that nice discussions like this, thick with information, are one of the reasons I love reading here.

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## nuuumannn (Jan 18, 2022)

Schweik said:


> Was the Emil really better than a Spitfire? In several ways it was more sophisticated, it had fuel injection and leading edge slats, combat flaps and a hydromatic / barometric controlled supercharger. But the Spitfire was so beautifully streamlined in spite of having 4' wider wingspan and a 40% greater wing area (with resulting superiority in turn performance) was actually faster than the Emil. I think the Spit I and the Emil were roughly equivalent. Which was better Spit or 109 went back and forth through the war with all the different variants, but they were always pretty close.



Let's look at the Emil versus the Mk.I. _Both had technical advantages and disadvantages over each other_, the list is quite extensive, but context again. The Emil had, despite a high wing loading benign stall characteristics, but it was a beast on the ground; poor visibility, poor lateral control on the ground, a heavy tail, awkward undercarriage geometry which made ground loops a mandatory aspect of operations, particularly after landing on rollout. Taxiing with the canopy open was a no no because the vibration from operating from grass strips meant the hinges wore out. In its favour the Emil has cannon armament, high altitude, high cruise speed at altitude and operating as escorts from altitude was able to carry out vertical combat manoeuvres to nullify the advantages that the Spitfire and Hurricane had over it in being superior low speed dog fighters. 

Emils also had variable pitch props, although the switch was initially located on the dashboard, which meant the pilot had to do a dance with his hands to activate it, a distraction in combat that led to the lever being mounted sensibly on the side console next to the power lever. The Spit I started the war with a giant block of wood on the nose, which to be fair was in the process of being replaced by a two-position variable pitch prop, which again was later updated with a fully CS prop. The German supercharger was a very efficient piece of technology that operated barometrically by varying its output based on its altitude, whereas the Merlin's supercharger was effective only at a prescribed altitude band.

In the BoB the Emil was formidable and widely recognised as having a better ceiling than the RAF fighters, but of course the way combat worked was that the German escorts would have to dive down on their adversaries. In commenting about the Bf 109's perceived superior altitude, one RAF pilot stated, "Well, they have to come down here and get us..." This meant the RAF fighters could take advantage of their virtues, better manoeuvrability, which as we know combat descended into twisting turning individual scraps where the superior dog fighters could get the better of the Bf 109s that couldn't pull as tight turns as its adversaries. At high angles of bank, those lift slats snapped open asymmetrically and spoiled the pilot's aim.

As for the claim the Emil was _arguably_ the best fighter in the world in 1939, it could at that time out perform the Spitfire I in altitude and it was more modern - no wooden prop, cannon armament, plus the Luftwaffe tactics learned in the Spanish Civil War meant that the Jagdgeschwader were better prepared for modern war.

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## Shortround6 (Jan 18, 2022)

The French got 4 Hawk 75s for test in Dec 1938. 
The service aircraft started going into service in March 1939. 
The A1 had four guns, supposedly seat armor, no PB glass and no protection on the fuel tanks. 
The A2 had six guns. First ones delivered in May 1939 and 97 of that batch (100 ordered) were delivered by the end of Sept.

The French were working on trying to protect the fuel tanks by Oct 21st 1939. The PIlots were asking for 8mm of armor behind the seat.
I don't know what the original armor was or if it was even fitted in some of the planes.

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## Schweik (Jan 18, 2022)

Shortround6 said:


> Point is you can you have the extra fuel or you can have the weight penalty.
> If the Germans are operating at less than a full load they have the advantage.
> If your Hurricane is operating at, say 50% full (combat then getting home) then a P-40 isn't going to have much more fuel or it is going to be carrying more weight.



Right, and this is true (as I said) for all longer-ranged aircraft, but the point is, the P-40 in this case is going to be at that 50% full point about another 100 miles further out. Which means it can be used as an escort fighter for medium ranged strikes, like escorting Baltimores against German airfields. 

If they are escorting a short range strike, like when escorting Hurricanes or other Kittyhawks carrying bombs, they are not going to use overload or external tanks (probably)

On the longer ranged strike, by the time they get into action they will (typically) no longer be in overload condition therefore at no particular defecit in performance or maneuvrability. Also helped they didn't have to lug around a vokes filter.

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## nuuumannn (Jan 18, 2022)

Schweik said:


> Yes. MS 406 was a 30's era fighter whose time had come and gone. And lets not forget the Bloch 150 / 152 series, which seems to have been a dud.



Again however, you field what you've got, not what you want. The background to France's fighter development was extensive, even the Amiot 143 was considered for a "fighter" role (!) as a _Multiplace de combat_. The French industry was in a woeful state at the outbreak of WW2 and buying US equipment added modern aircraft to the polyglot mix of aircraft, some of which were good, many of which were pretty below average. The French air force was definitely not materially prepared for defeating the Germans (funny how the Germans somehow knew this...), but it was the government's mind-set that caved in first. Had the country had more stout leadership its army could have been able to defeat the Germans on the ground - better tanks for starters, but the French collapse happened quicker than what was expected, catching even the Germans by surprise.

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## Schweik (Jan 18, 2022)

Yes France had poor leadership, some really bad bureaucratic / administrative issues inside their military and government, and no unity. The nation was deeply split, with communist sympathizers on one side and fascists on the other, and most of the people caught in the middle very frustrated with the whole situation. France has been split this way since the revolution in the 18th Century. WW I had also been such a nightmare for France, they (the common people) really wanted to avoid another war.

They did have quite a mix of aircraft, some completely ridiculous, (like the Amiot 143) and some quite nice ones like D.520 and Br 693. Same with the tanks, the SOMUA S-35 was quite promising. I often wonder (and considered starting a thread on this) if they could have done much better if they had had another 3 or 4months. So many new war machines were either just arriving at their units or were weeks away from arriving. French and French-Colonial troops fought well under LeClerc and in the Free French army after D-Day. 

But the main issue in 1940 was as you said, they lacked the leadership and were not unified. It's a very hard thing to fight a brutal war like WW2, and their heart just wasn't in it as a nation. I don't know if that is better or worse than say, Germany who _did_ have a purpose and unity, but it was a delusional, evil and ultimately self-destructive one!

It was a difficult tightrope to walk. England had some trouble with ambivalence among some of their leaders too. But luckily for all of us, they walked that fine line and ultimately hung tough long enough to bring their Commonwealth allies into action, and the US.

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## Thumpalumpacus (Jan 18, 2022)

nuuumannn said:


> [...] but it was the government's mind-set that caved in first. Had the country had more stout leadership its army could have been able to defeat the Germans on the ground [...]



Anyone looking to read about this further should read William Shirer's _The Third Republic_, a history of that era of French history.

The political divisions which made their politics so fractious filtered down to the people of the nation, which of necessity included the conscripts manning the tanks, planes, and Maginot line. The disunity infected the ranks imo.

Was it General Brooke who toured French positions in 1939 and commented in his diary about the sullen, unenergetic mien of the troops he saw there? Whoever it was, it seems pertinent here, because the failures of French leadership in government seem to have filtered down to the level of private soldier. The divisions in French society at that time seems to have undermined the morale of their army, to me.

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## Jabberwocky (Jan 18, 2022)

Schweik said:


> Didn't the Spitfire have an unprotected or lightly protected (i.e. no self sealing) fuel tank in front of the pilot?



It's a long and complicated story (as is usual with the Spitfire).

Mk Is initially didn't have any self sealing tanks. Then they got Linatex covering for the lower tank only (mod approved in April 1940) and then a fully self sealing lower tank (mod approved in July 1940). Upper tank was not self sealing, simply because there wasn't the room for it.

Mk Is (and Mk IIs) received a curved aluminum 'deflection plate' over the top tank in early 1940 (at least as early as February 1940 on a Mk II trials aircraft). This is variously given as 3 mm, 3.9 mm, 4 mm or 6 mm thick. 

Sometime in 1940, the rear fireproof bulkhead on the Mk I was improved and extended to better protect the fuel tank (and the pilot). I think it was 8 mm of aluminum, plus an asbestos layer.

All the way out to the Mk 22, the top tank wasn't self sealing. *Except for the Mk VIII and Mk VII,* where the did introduce a self sealing top tank. The December 1943 manual Mk VII & Mk VIII manual lists all four fuel tanks as self sealing. As I understand it, more space was made available in the airframe by changing the upper fuel tank dimensions and lowering it directly onto the bottom tank.

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## Greyman (Jan 18, 2022)

Jabberwocky said:


> Mk Is (and Mk IIs) received a curved aluminum 'deflection plate' over the top tank in early 1940 (at least as early as February 1940 on a Mk II trials aircraft). This is variously given as 3 mm, 3.9 mm, 4 mm or 6 mm thick.



10 swg duraluminium (ie: 3.251 mm)

They were being produced with this protection by August 1939.

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## Schweik (Jan 18, 2022)

Jabberwocky said:


> It's a long and complicated story (as is usual with the Spitfire).
> 
> ...
> 
> ...



Yet another reason to love the Spitfire Mk VIII.


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## GregP (Jan 18, 2022)

nuuumannn said:


> Let's look at the Emil versus the Mk.I. _Both had technical advantages and disadvantages over each other_, the list is quite extensive, but context again. The Emil had, despite a high wing loading benign stall characteristics, but it was a beast on the ground; poor visibility, poor lateral control on the ground, a heavy tail, awkward undercarriage geometry which made ground loops a mandatory aspect of operations, particularly after landing on rollout. Taxiing with the canopy open was a no no because the vibration from operating from grass strips meant the hinges wore out. In its favour the Emil has cannon armament, high altitude, high cruise speed at altitude and operating as escorts from altitude was able to carry out vertical combat manoeuvres to nullify the advantages that the Spitfire and Hurricane had over it in being superior low speed dog fighters.
> 
> Emils also had variable pitch props, although the switch was initially located on the dashboard, which meant the pilot had to do a dance with his hands to activate it, a distraction in combat that led to the lever being mounted sensibly on the side console next to the power lever. The Spit I started the war with a giant block of wood on the nose, which to be fair was in the process of being replaced by a two-position variable pitch prop, which again was later updated with a fully CS prop. The German supercharger was a very efficient piece of technology that operated barometrically by varying its output based on its altitude, whereas the Merlin's supercharger was effective only at a prescribed altitude band.
> 
> ...



You think the early Spitfire was a better low-speed dogfighter than the Bf 109E? 

I think it was the other way, with the Bf 109E slats helping the Emil hang in there in turns, even if stalled, and the Spitfire being better at medium to high speeds, when the Bf 109E controls got too heavy to be of much use.

But, hey, we don't exactly have an example of each to test it out with, do we? Damn! It would have been great fun.

I'll hoist a Spitfire Ale and say, "another round ..."

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## Schweik (Jan 18, 2022)

Spitfire Mk 1 - 5,935 lbs / 242 sq ft wing area = 24 lb / sq ft wing loading
Bf 109E - 5,700 lbs / 174 sq ft wing area = 32 lb / sq ft wing loading

I just googled the weights so there might be some variance in those numbers, but I think that is in the ballpark.

And I don't know how much the slats helped but that is a lot of ground to make up for. As in about a 25% advantage for the Spit.


Also in the Med in 1942-43, with Spit V vs. 109F, anecdotally (in the various pilot interviews) all the British and American and most of the German pilots seemed to agree, the Spitfire could _easily_ out-turn the 109. And I had always understood the 109F to be the best turning variant, though I know that depends on various factors.

German tactics seemed to be pretty similar to what I've read for the BoB (and partly mentioned upthread) i.e. attack from above, preferably with surprise, disengage and try again. Try to avoid the turning fight.

This was also one of the reasons why the German fighter pilots hated flying escort.


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## wuzak (Jan 19, 2022)

GregP said:


> You think the early Spitfire was a better low-speed dogfighter than the Bf 109E?



I believe that RAE or ADFU test pilots found that to be the case.




GregP said:


> I think it was the other way, with the Bf 109E slats helping the Emil hang in there in turns, even if stalled, and the Spitfire being better at medium to high speeds, when the Bf 109E controls got too heavy to be of much use.



What was determined was that service pilots were unable to turn as tightly in Spitfires as the test pilots were in the 109E. With experienced test pilots in both, the Spitfire handily out-turned the 109.

German pilots were more experienced before the BoB, and would likely have more confidence to get close to the limits of the aircraft than their British counterparts.

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## FLYBOYJ (Jan 19, 2022)

Schweik said:


> Spitfire Mk 1 - 5,935 lbs / 242 sq ft wing area = 24 lb / sq ft wing loading
> Bf 109E - 5,700 lbs / 174 sq ft wing area = 32 lb / sq ft wing loading
> 
> I just googled the weights so there might be some variance in those numbers, but I think that is in the ballpark.
> ...


You have to compute the additional wing area once the slats are deployed, that will paint a better picture of the wing loading once the -109 is in that configuration.

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## Jabberwocky (Jan 19, 2022)

wuzak said:


> I believe that RAE or ADFU test pilots found that to be the case.
> 
> 
> 
> ...



The Germans thought the Spitfire was better turning than the 109E as well. Quoting from the August 1940 German trials of a 109-E3, 110C, Spitfire, Hurricane and a Hawk 75 "Curtiss":

"Before turning fights with the Bf 109 E type, it must be noted in every case, that *all three foreign planes have significantly smaller turning circles and turning times.*
An attack on the opponent as well as disengagement can only be accomplished on the basis of existing superiority in performance." 

Both Spitfire and Hurricane had the older, two pitch propellers - I'm not sure how much that hurt/helped turn performance.


The RAF's Hurricane Mk I vs a 109-E trials from May 1940 found the British could go from in front of the Germany fighter to behind it in the space of four circles. The RAF also found that the Hurricane's turning circle was about 10% better than that of the Spitfire. 

June 1940 Spitfire Mk I vs 109-E trials stated "*the Spitfire out-turned the Messerschmitt almost as easily as the Hurricane*".

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## wuzak (Jan 19, 2022)



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## BiffF15 (Jan 19, 2022)

Jabberwocky said:


> The Germans thought the Spitfire was better turning than the 109E as well. Quoting from the August 1940 German trials of a 109-E3, 110C, Spitfire, Hurricane and a Hawk 75 "Curtiss":
> 
> "Before turning fights with the Bf 109 E type, it must be noted in every case, that *all three foreign planes have significantly smaller turning circles and turning times.*
> An attack on the opponent as well as disengagement can only be accomplished on the basis of existing superiority in performance."
> ...


Jabberwocky,

Are you able to identify "all three foreign planes" from your passage? I'm assuming it's the Hurricane & Spitfire, but am curious what the third A/C might be.

Cheers,
Biff


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## pbehn (Jan 19, 2022)

BiffF15 said:


> Jabberwocky,
> 
> Are you able to identify "all three foreign planes" from your passage? I'm assuming it's the Hurricane & Spitfire, but am curious what the third A/C might be.
> 
> ...


It is in the line above Spitfire, Hurricane and Hawk 75. However by August 1940 the Spit and Hurricane were both fitted with CS props and the Spitfire MkII was starting to come into service.

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## Snautzer01 (Jan 19, 2022)

Curtis hawk is mentioned.

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## PAT303 (Jan 19, 2022)

Jabberwocky said:


> The RAAF pranged a lot of Spitfires around Darwin as well.
> 
> Anthony Cooper's _Darwin Spitfires_ book gives 36 Spitfire VCs damaged badly enough during takeoff or landing between February and September 1943 to require attention from the Repair and Servicing unit. He attributes this to the conditions inherent to the bush airfields the Spitfires were operating from. These were narrow and made of dirt (compared to the wide grassy airfields used by in the UK and in NSW). Of the 36 Spitfires, only seven (~20%) were actually damaged at the main paved Darwin airfield, the rest were damaged at the smaller ancillary dirt fields.


117 Spitfires were ridden off at Darwin to all causes.

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## BiffF15 (Jan 19, 2022)

Thanks gents, missed the obvious!


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## PAT303 (Jan 19, 2022)

wuzak said:


> View attachment 655125
> 
> 
> View attachment 655123
> ...


My take is a rooky pilot in the Spit or Hurri could be bested by an experienced 109 pilot but when equal pilots in both planes meet the 109 looses out.

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## pbehn (Jan 19, 2022)

BiffF15 said:


> Thanks gents, missed the obvious!


Throughout the war machines and information became obsolete very quickly, testing enemy equipment and spying may have been a great way of deceiving yourself, an early 1940 Hurricane was nothing like what was sent up in the BoB.

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## Shortround6 (Jan 19, 2022)

Looking at Wuzak's post again.







That is for a minimum radius turn_ without height loss. _Or a _sustained turn_.
Both planes could easily hit 5 1/2 to 6 Gs in a turn. But they would have to trade forward speed or trade altitude in order keep the speed above stall. 
The 109 with it's slates could not actually turn better, as seen above and in other documents/tests.
The Slats on the 109 gave a much more noticeable warning of approaching stall than the Spitfire did. That is the advantage the 109 gave some rookie pilots. 
Please note that the early Spitfires were noted for having a very powerful elevator which was easy to over control in turns. Later Spits (and I believe we are talking about sometime in 1940 here?) had a bob weight installed the control circuit that increased the force needed on the stick to reduced sensitivity. 

I would venture to guess that an older Spitfire, that is one with the two pitch propeller would have trouble with 2.65 G turn in test. The two pitch propeller would be in coarse pitch and the prop would be close to stalling at that speed (or at least operating very, very inefficiently) and with less thrust the plane would _not_ be able to sustain the 2.65 turn rate without descending. 

I would also note that a pilots ability to maintain a steady rate turn is very, very hard.

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## FLYBOYJ (Jan 19, 2022)

PAT303 said:


> My take is a rooky pilot in the Spit or Hurri could be bested by an experienced 109 pilot but when equal pilots in both planes meet the 109 looses out.


Back up even further - it will be a matter of who sees who first and how that tactical advantage is exploited.

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## Shortround6 (Jan 19, 2022)

PAT303 said:


> 117 Spitfires were ridden off at Darwin to all causes.


The general rule of thumb was that a squadron was going to write off it's initial issue of planes in the first 6 months and replacement aircraft would be used up at about about rate during service. Varies a bit with actual sortie rate of course.

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## FLYBOYJ (Jan 19, 2022)

*at·tri·tion*

the action or process of gradually reducing the strength or effectiveness of someone or something through sustained attack or pressure.


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## PAT303 (Jan 19, 2022)

FLYBOYJ said:


> Back up even further - it will be a matter of who sees who first and how that tactical advantage is exploited.


Can't argue with that.

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## PAT303 (Jan 19, 2022)

Shortround6 said:


> The general rule of thumb was that a squadron was going to write off it's initial issue of planes in the first 6 months and replacement aircraft would be used up at about about rate during service. Varies a bit with actual sortie rate of course.


One of the biggest causes of write off was hitting tree's, the dust was so bad pilots would only realise they have gone off the strips after they hit one.

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## pbehn (Jan 19, 2022)

PAT303 said:


> One of the biggest causes of write off was hitting tree's, the dust was so bad pilots would only realise they have gone off the strips after they hit one.


Couldnt they have installed tree catchers or something?

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## Shortround6 (Jan 19, 2022)

Assumes pilot can see the crewman on the wingtip.
Assumes the crewman can see the tree also

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## Schweik (Jan 19, 2022)

FLYBOYJ said:


> Back up even further - it will be a matter of who sees who first and how that tactical advantage is exploited.



That brings you back to tactics like the Finger-four, the use of radios etc. The standard Finnish tactic when encountering enemy fighters (which I believe was similar to the German) was one pair from the flight makes a shallow high speed climbing turn to the right, the other turns left and climbs. Whichever the enemy fighter(s) go for becomes the bait, using their superior power and climb rate to stay ahead of their pursuers. The other pair then chases the pursuing fighters and shoots them down.

Early fighters had the turtle decks and many of them lacked rear-view mirrors initially... it became very easy to become focused on the target and forget that you were at risk... and as many early fighters (especially in Russia) either lacked radios or had radios that either didn't work very well or that they hadn't learned to use properly, a useful warning either never came or came too late. This is how a lot of fighters were shot down 'without ever seeing their enemy' - not just in the initial attack from out of the sun.






Other tactic typically used by German pilots was the rolling scissors; when faced with a better turning fighter, you roll and turn one way, then roll again and turn the other way. Bf 109 had a bit better roll rate than the Spitfire and considerably better than the Hurricane. In this manner they could sometimes get behind their opponent. This is also what the Kittyhawk pilot did against the Spitfire in that famous Australian test. Bf 109s were particularly good at this because of the slats.





Another typical tactic also used was the high or low Yo-Yo. The high Yo-Yo was a way to use some extra energy (and / or an exceptional climb rate) to make a climbing turn (what the Russians would call a 'vertical turn' ) and thus turn inside a normally better turning aircraft. I believe this was a tactic often used by German pilots, particularly in Russia. Japanese pilots did this against Allied fighters in the Pacific too.






A low Yo-Yo was a similar tactic where you have a fast diving aircraft and / or are running out of energy, you make a diving turn (picking up speed in the process) and then zoom climb up, cutting the circle. This was a standard tactic used by US fighter pilots in the Pacific especially, but also in the Med.

I mention these just as a reminder that a dog fight wasn't necessarily just a matter of turning in circles. Pilots figured out many ways to take advantage of their aircraft's strengths and exploit their enemy's weaknesses.


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## FLYBOYJ (Jan 19, 2022)

Schweik said:


> I mention these just as a reminder that a dog fight wasn't necessarily just a matter of turning in circles. Pilots figured out many ways to take advantage of their aircraft's strengths and exploit their enemy's weaknesses.


Good stuff but be aware that some of us have actually participated in these maneuvers (my experience is very novice compared to our resident Eagle driver, Biff) and these maneuvers and tactics have been discussed countless times on this forum by many. If you don't see you're enemy coming, all this is void. Every doctrine written by leading fighter pilots involves the ability to see the enemy first.

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## Shortround6 (Jan 19, 2022)

Schweik said:


> Bf 109s were particularly good at this because of the slats.


The 109 gets a lot of credit for the slats.

It was done but depending on the slats means you are at the very bottom of the energy zone. 
They are automatic slats, pilot has no control over them (can't pop them at 250mph in level flight).
They also don't come out until the airflow over the wing surface is at a certain point, like 10-15kph above stall. 
Granted in a Hi G turn that could be close to 300kph above true airspeed and nowhere near the stall speed at landing. 
It also means that the the wing is just about stall which means the angle of attack of the wing is probably 12-14 degrees above where the direction of flight is pointed. 
In other words you are in a high drag situation. You will need several minutes to get your air speed back up to near full speed flying nearly straight and level.

If your (and a wing man) have gotten into a turning fight with one or two opponents then it may be a good tactic. If you are outnumbered then getting out of Dodge is may be the better strategy. If you have gotten your slats to deploy then somebody in the furball has a better energy status than you do and they are going to be on your tail very soon. 

Not saying that the German and Japanese didn't use the hi yo-yo or the low yo-yo or some variation of it. But you get the slats to pop on the yo-you you might have already slowed down to much.

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## special ed (Jan 19, 2022)

This tactics/awareness discussion brings to mind an account from a book read about 70 years ago. The British WW1 ace was flying alone near or over German lines looking for the enemy when he spotted a German enjoying aviating. His description was that the German must have been a new pilot as he was enjoying the beautiful day and flying the rims of the of the clouds circling and climbing. The British pilot thought it was a shame to shoot down someone who enjoyed flying that much but realised the man could become a great flyer and so shot him down without the German ever seeing the danger. I can no longer remember the book or the pilot.

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## Schweik (Jan 19, 2022)

Shortround6 said:


> The 109 gets a lot of credit for the slats.
> 
> It was done but depending on the slats means you are at the very bottom of the energy zone.
> They are automatic slats, pilot has no control over them (can't pop them at 250mph in level flight).
> ...



Right, I don't disagree with any of that. Many pilots were certainly caught who had never seen their opponents. Deploying the slats definitely increased drag, and from my understanding they had some problems with the slats on the Emil, which were sorted out with the Franz.

But it was often also the situation that the pilot did survive an initial encounter, or saw the enemy coming, but then found themselves in a desperate situation in a close-quarters fight. They typically worked out standard tactics to exploit their aircraft's strengths. These were used over and over again.

The Scissors was described several times by German pilots as a 'survival method' when they did get caught in a turning fight, which was actually not that unusual depending on the circumstances. For example when they had to fly escort, they couldn't just stay above the enemy fighters until the circumstances were ideal - they had to stay and fight or else the bombers would be shot down. The Soviets also talk a lot about how the Bf 109 pilots used 'vertical turns' to outmaneuver their own (better turning) fighters. I found it quite interesting that the Scissors was also mentioned in that Australian test P-40E vs Spitfire V using combat experienced pilots.

The famous Thach Weave used by F4F pilots in the Pacific was also basically a scissors.

Similarly, the 'low-yo-yo' became a go-to survival technique for US P-40 pilots when facing zeros. This is how 14 victory ace Robert DeHaven described it:

_"[Y]ou could fight a Jap on even terms, but you had to make him fight your way. He could outturn you at slow speed. You could outturn him at high speed. When you got into a turning fight with him, you dropped your nose down so you kept your airspeed up, you could outturn him. At low speed he could outroll you because of those big ailerons ... on the Zero. If your speed was up over 275, you could outroll [a Zero]. His big ailerons didn't have the strength to make high speed rolls... You could push things, too. Because ... f you decided to go home, you could go home. He couldn't because you could outrun him. [...] That left you in control of the fight."_

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## Schweik (Jan 19, 2022)

FLYBOYJ said:


> Good stuff but be aware that some of us have actually participated in these maneuvers (my experience is very novice compared to our resident Eagle driver, Biff) and these maneuvers and tactics have been discussed countless times on this forum by many. If you don't see you're enemy coming, all this is void. Every doctrine written by leading fighter pilots involves the ability to see the enemy first.



I am aware of that, I wasn't trying to 'school' you or Biff, but some people posting here don't know all of this. 

And i agree, good eyesight is the fighter pilots first and most important trait. Second however may be knowledge of some of these tactics, or that ability to endure high G.

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## FLYBOYJ (Jan 19, 2022)

Schweik said:


> I am aware of that, I wasn't trying to 'school' you or Biff, but some people posting here don't know all of this.


You'll be surprised how many do!

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## Schweik (Jan 19, 2022)

Well I didn't when i first started reading this forum. It took me many hours of research to figure that out.

It's not just the matter of whether these techniques exist, but the context in which they were used (and by whom). 

If people generally feel that post is redundant or not useful I'll remove it.


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## FLYBOYJ (Jan 19, 2022)

Schweik said:


> Well I didn't when i first started reading this forum. It took me many hours of research to figure that out.
> 
> It's not just the matter of whether these techniques exist, but the context in which they were used (and by whom).
> 
> If people generally feel that post is redundant or not useful I'll remove it.


No, you don’t have to remove it, but just understand there’s many (if not the majority ) in this forum who are not novices


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## Schweik (Jan 19, 2022)

Based on the posts i see, I think it's a mix. But even experts on one issue are often novices on another. YMMV.

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## BiffF15 (Jan 19, 2022)

Gents,

I will throw out some perspectives and feel free to fire questions back.

First, I'm impressed with the knowledge you guys display on something that is an almost must see to believe / do to understand. I can not overstate that!

Shortround6 I agree with your assessment of the Bf 109 (I think I spaced that correctly) in that the Spit handily out turned it. Also your grasp of the simple fact to turn and maintain airspeed requires a downward spiral (or you need to give up altitude) is absolutely correct. 

The key that I will point out is an airplane has a speed that it turns best at, or one that will keep your opponent from bringing his nose to bear in a turning fight (assuming he is somewhere between / behind your 4-8 o'clock). At this speed you can steepen your turn (start what looks like a low yo yo) and hold your speed. That requires you to increase G to control speed but you are giving up a LOT of altitude. The goal is to be just nose low enough to hold your desired speed / G. If you shallow out you will burn off airspeed and your circle will eventually grow. Bigger circle or going slower lets the smartly flown bandit enter the gun employment zone, as does the low yo yo type turn (all this assumes you are defensive) as it gives him more room to maneuver.

Schweik,

Your understanding of the scissors is great with two small corrections. First, your top picture shows two drawings, the upper one is a Flat scissors, while the lower of the two is a rolling scissors. You describe the Flat but call it a rolling. Maybe in WW2 terms they just called it a scissors or a rolling scissors, but under todays terminology, they are two different beasts. Also, the flat scissors is used when both aircraft are out of energy, or one has a better turn than the others. It favors the better turning plane (slats or not). The rolling scissors usually rewards the better power to weight, or the guy who arrives there with a speed / energy advantage. The rolling scissors is two guys seeing who can fly the greatest distance while covering the least distance over the ground. Or the guy who can fly the biggest circles (will cover the lessor distance across the ground).

Also mentioned above is the bulkhead behind the pilot. The biggest thing I can say there, is if you want to survive, you need to keep checking your six, and if you get jumped you CAN NOT LOSE SIGHT of the guy trying to kill you (hated this about the movie Dunkirk). That means you are moving around in the seat, mashing your face / helmet against the canopy, flying, all while looking over your shoulder. There are many axioms, one of which is, "lose sight, lose the fight". And to quote Marissa Tomei in My Cousin Vinney, it's "dead on balls accurate".

Next is the Bf 109 and it's flight controls. I have read that they were heavy in roll, and light in pitch or that they weren't harmonized evenly. Also I have read that the slats do not deploy evenly at times, which can make it difficult to fly well / aim. I have also watched a well regarded airshow pilot get checked out on one (video) and he repeated that you brought the power in very slowly, and you didn't stop flying it until you shut down the motor. In other words it was ready to bite you at all times. Fly it long enough and a pilot can not only overcome a planes bites, but do well in it (there are enough Experten to prove this). If a Bf 109 guy is exploiting the vertical while fighting a Soviet guy, or anyone else, it's one of two things. A, he either understands how and when to do it, or B he has more power / energy.

The biggest thing I take away from reading about all these engagements, is the guys talking about them I think describe it differently than I would. It could either be they didn't understand fully what they were doing, or they did something that the enemy didn't know how to counter (good training vice poor). I've listened to WW Nam era guys talk about lag rolls, and I shudder. They got away with it, but that's not the best way to accomplish what they wanted to do. An adversary who was WATCHING them do it, and KNEW what to do would have stuffed them every time. Big picture I take with a grain of salt some of what I read and try to filter it through my individual understanding of what it is they were doing / trying to do. Also, these guys training would be considered very light compared to what we get today.

Cheers,
Biff

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## FLYBOYJ (Jan 19, 2022)

Schweik said:


> Based on the posts i see, I think it's a mix. But even experts on one issue are often novices on another. YMMV.


You’re right, 43 years in the business and I learn something daily, at the same time understand the level of knowledge in this forum, so now I’m asking you to move on.


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## Schweik (Jan 19, 2022)

FLYBOYJ said:


> You’re right, 43 years in the business and I learn something daily, at the same time understand the level of knowledge in this forum, so now I’m asking you to move on.



Post edited


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## tomo pauk (Jan 19, 2022)

nuuumannn said:


> The German supercharger was a very efficient piece of technology that operated barometrically by varying its output based on its altitude, whereas the Merlin's supercharger was effective only at a prescribed altitude band.



The supercharger _drive_ on the DB 601 was better than that of the Merlin III. The S/C itself - probably not. On 87 oct, Merlin was making better power from 15000 ft up, granted the advantage was not a big one. The 100 oct fuel that allowed for greater boost at lower altitudes, meaning now that Merlin III was making better at alltitudes. See here. 




nuuumannn said:


> In its favour the Emil has cannon armament, high altitude, high cruise speed at altitude and operating as escorts from altitude was able to carry out vertical combat manoeuvres to nullify the advantages that the Spitfire and Hurricane had over it in being superior low speed dog fighters.



Emil will cruise high and fast due to having a lot of altitude and speed when making the landfall at the SE English coast. Spitfire does not have that luxury, it's modus opearndi was to scramble as fast as possible to beet the threat head-on, if possible. 
Not every Emil was armed with cannons, the E-1 was armed with 4 LMGs; granted LW was trying to up-gun those during 1940. 
Bf 109E-1 was delivered in 1056 copies by 30th June 1940, with another 405 to be delivered until end of February 1941. E-3: 1198 copies until end of July 1940. E-4: 185, plus 609 to be delivered until end of January 1941.

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## FLYBOYJ (Jan 19, 2022)

Schweik said:


> So go ahead and ban me.


You were politely asked to move on, but why am I not surprised about your childish and ignorant behavior, yes enjoy cyberspace.


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## Thumpalumpacus (Jan 19, 2022)

Sad to see all around.

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## Shortround6 (Jan 19, 2022)

.


tomo pauk said:


> The supercharger _drive_ on the DB 601 was better than that of the Merlin III. The S/C itself - probably not. On 87 oct, Merlin was making better power from 15000 ft up, granted the advantage was not a big one. The 100 oct fuel that allowed for greater boost at lower altitudes, meaning now that Merlin III was making better at alltitudes. See here.
> 
> 
> 
> ...


At least in 1943-44 they introduced block numbers;:
A Spitfire MK I could have the two Blade prop, it could have the two speed prop, it could have the constant speed prop. It could have no protection, it could limited protection, it could somewhat more protection, it could have the modified elevator controls, or not.
Gross weight could be around 5820lbs to over 6120lbs depending on the propeller and protection and radios. 

109s had changes in protection. They had at least 2 if not more than different engines, they had four 7.9mm machine guns or two 7,9mm guns and two 20mm MG/FFs or two 7.9mm guns and two 20mm MG/FFMs. Probably some other stuff. 
109s didn't go out of production until the summer of 1941. A lot of improvements over what was used in most of the BoB. 

But then the Spit II was trickling into production at the start of the BoB but not in significant numbers. 

We need a spread sheets and color codes to keep up with what was the current versions.


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## PAT303 (Jan 19, 2022)

pbehn said:


> Couldnt they have installed tree catchers or something?








Bees Creek Sattler Airstrip, Bees Creek, Northern Territory, Australia


Bees Creek Sattler Airstrip, Bees Creek, Northern Territory, Australia, airfield, -12.542467, 131.053614




vwma.org.au




Makes you wonder why they didn't cut them back.


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## wuzak (Jan 19, 2022)

Schweik said:


> This is also what the Kittyhawk pilot did against the Spitfire in that famous Australian test. Bf 109s were particularly good at this because of the slats.



Is this the one where the Kittyhawk could get away from a Spitfire that got on his tail, but could never get on the tail of the Spitfire?


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## PAT303 (Jan 19, 2022)

BiffF15 said:


> CAN NOT LOSE SIGHT of the guy trying to kill you (hated this about the movie Dunkirk).


Or the part where he pulled lead on the 109 for a nice deflection shot but only fired when it entered the crosshairs, those .303's must have been loaded with hypervelocity ammo.

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## Vincenzo (Jan 19, 2022)

tomo pauk said:


> Bf 109E-1 was delivered in 1056 copies by 30th June 1940, with another 405 to be delivered until end of February 1941. E-3: 1198 copies until end of July 1940. E-4: 185, plus 609 to be delivered until end of January 1941.


This came from a old forum, just i don't remember what, maybe 12 o'clock high, there is not E-1 production in '41

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## Greyman (Jan 19, 2022)

BiffF15 said:


> First, I'm impressed with the knowledge you guys display on something that is an almost must see to believe / do to understand. I can not overstate that!



As much as desktop flight sims get an eye-roll from many -- I wouldn't have even close to the grasp of air combat I do without having played them (years ago, now). No amount of book reading would do.



BiffF15 said:


> The biggest thing I take away from reading about all these engagements, is the guys talking about them I think describe it differently than I would.



That was another thing that WWII fighter plane games / sims impressed upon me -- that a lot of the old pilots might full well have known what they were doing but just didn't have the formal training / nomenclature to talk about it the way a combat pilot would now.

After years of playing these games I fully understood all of the main concepts and basic maneuvers -- scissors, lag pursuits, energy, yoyos, etc., etc. -- I just had no idea these things had formal names or were codified concepts. I just intrinsically knew _'... if we're in *this *situation, I do *that *... if we're in *that *situation, I do *this *...'. _

If you were to watch one of my play dogfights and write a commentary on it, you'd be able to fill and entire page to describe what happened ... but my description (at the time) would have simply read like a WWII combat report; 'then I got behind him and gave him a two-second squirt at 100 yards.' I think something similar is going on with a lot of combat descriptions from an earlier era.

I always think back to an anecdote I unfortunately had to hear about second-hand;

In the late 90s one of these online WWII flight sims had their yearly convention where players could meet up, and as per usual had some actual WWII vets come and talk about their flying. During a Q&A with a USAAF fighter pilot, one keen-as-mustard player asked a very detailed, 'nerdy', question that would have been better put to a modern fighter pilot. The WWII vet said;

_"ACM? BVR? Those sound like something you catch off a toilet seat. We just flew, son."_

I can't remember the exact acronyms of the anecdote but you get the picture ...

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## Greg Boeser (Jan 19, 2022)

FLYBOYJ said:


> You were politely asked to move on, but why am I not surprised about your childish and ignorant behavior, yes enjoy cyberspace.


Wow. That was harsh, considering what certain other members have gotten away with. But, then, he did request it.
That last, deleted post must have been so.ething.


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## FLYBOYJ (Jan 19, 2022)

Greg Boeser said:


> Wow. That was harsh, considering what certain other members have gotten away with. But, then, he did request it.
> That last, deleted post must have been so.ething.


All I can say is refer to the forum rules. Now I'd like to move on with this very interesting thread

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## Greg Boeser (Jan 19, 2022)

Well, I've always been a fan of the second stringers. The P-40, while a capable aircraft, just wasn't in the same class as the first tier European fighters. I include in the first tier Spitfires, Typhoons, Bf 109s, Fw 190s, P-38s, P-47s, P-51s, the late, DB 605 engined, Italian fighters. So, second tier, along with the Hurricane, another one of my favorites. Something about rooting for the underdog.

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## Shortround6 (Jan 19, 2022)

Well, you can argue that the Hurricane was first tier, perhaps only for a little while 

The P-40 was never first tier. It may have been useful, It may have helped hold the line, but it was never 1st tier.

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## Greg Boeser (Jan 19, 2022)

The Hurricane was first tier right up to the point the first Bf 109Es show up.

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## FLYBOYJ (Jan 19, 2022)

Greg Boeser said:


> The Hurricane was first tier right up to the point the first Bf 109Es show up.


I think the Hurricane was one of the most under-rated fighters of WW2


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## Greg Boeser (Jan 19, 2022)

Always a bridesmaid, never a bride.

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## Shortround6 (Jan 19, 2022)

Greg Boeser said:


> The Hurricane was first tier right up to the point the first Bf 109Es show up.


 Yep, 
But the P-40 didn't show up until the 109E had been in service for 15-16 months. And the first few hundred weren't ready for combat use. (forget about armor and self sealing tanks, the engines had to be down graded to 2770rpm and 950hp at 8,000ft). Early Tomahawks in Britain couldn't get the .50 cal guns to work a large amount of the time leaving them with just four .30 cal guns compared to the over 18 month old 109E-1s four 7.9mm guns. 
By the time the Tomahawks were showing in numbers (with better engines) and armor and SS fuel tanks the 109 had 20mm MG/FFM cannons with mine shells and had DB601N engines. 
BTW, about the same month the first Tomahawks get off the boat the Hurricane II with the Merlin XX engine makes it's first appendence at an operational squadron. 
As I said, British pilots were full of joy to get Tomahawks so they could rid of Westland Lysanders. 
A lot of things are relative

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## Greg Boeser (Jan 19, 2022)

Were there any Bf 109E-1s in frontline service by the time Tomahawks are operational? And what gave you got against Lysanders? I read their incredibly low speed was a defensive advantage. A real fighter plane wouldn't be able to stay with them.

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## BiffF15 (Jan 19, 2022)

Greg Boeser said:


> Were there any Bf 109E-1s in frontline service by the time Tomahawks are operational? And what gave you got against Lysanders? I read their incredibly low speed was a defensive advantage. A real fighter plane wouldn't be able to stay with them.


Greg,

Being able to fly slow is a strength, however if your opponent is markedly faster and more maneuverable it relegates one to strafe rag status in the case of a Lysander versus a 109.

Cheers,
Biff

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## Shortround6 (Jan 19, 2022)

A fair number of army co-operation squadrons had been equipped with Lysanders, both in France in in England. 

Sopwith Salamanders would have just wonderful against "real fighters" too. 

on a more serious note "118 Lysanders were lost in or over France and Belgium in May and June 1940, of a total of 175 deployed"

and 

"The view of Army AOP pilots was that the Lysander was too fast for artillery spotting purposes, too slow and unmanoeuverable to avoid fighters, too big to conceal quickly on a landing field, too heavy to use on soft ground and had been developed by the RAF without ever asking the Army what was needed"

The Lysander may have had a slow flying speed but it also had very heavy controls which made changes of direction ponderous. 
Slow and agile might work. Slow and not agile was a recipe for disaster.

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## FLYBOYJ (Jan 19, 2022)

IIRC Lysanders did achieve several kills against -109s. I think someone once posted a list of Lysander kills


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## FLYBOYJ (Jan 19, 2022)

Shortround6 said:


> Sopwith Salamanders would have just wonderful against "real fighters" too.


I would have gone with a Gunbus...

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## Shortround6 (Jan 19, 2022)

FLYBOYJ said:


> IIRC Lysanders did achieve several kills against -109s. I think someone once posted a list of Lysander kills


Well, I keep posting the kills (claims) of Avro Anson/s (one Anson?) 
Nobody thought using Avro Ansons was a good idea for air to air combat.

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## Clayton Magnet (Jan 20, 2022)

Greg Boeser said:


> Were there any Bf 109E-1s in frontline service by the time Tomahawks are operational?


Bf 109F's were in service months before the first Tomahawk's, so I would assume all the E-1's had been replaced by at least E-3's by then. Maybe training units had the early Emil's by 1941?


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## Shortround6 (Jan 20, 2022)

According to some sources some of the E-1s were rebuilt as E-4s or later. 
Some got DB601N engines and some got 20mm cannon and patches can be seen where the 7.9mm mgs used to be.

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## pbehn (Jan 20, 2022)

FLYBOYJ said:


> IIRC Lysanders did achieve several kills against -109s. I think someone once posted a list of Lysander kills


Compared to the Po-2 on the Russian front the Lysander is a speed merchant, the Po-2 maximum speed is just 22mph faster than the Lysander stall speed, something they could make use of but I am sure they would have preferred not to.


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## Snautzer01 (Jan 20, 2022)

pbehn said:


> Compared to the Po-2 on the Russian front the Lysander is a speed merchant, the Po-2 maximum speed is just 22mph faster than the Lysander stall speed, something they could make use of but I am sure they would have preferred not to.


The po-2 slowness could be a weapon. More then 1 luftwaffe pilot stalled and crashed trying to get it in his sights.

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## MikeMeech (Jan 20, 2022)

Shortround6 said:


> A fair number of army co-operation squadrons had been equipped with Lysanders, both in France in in England.
> 
> Sopwith Salamanders would have just wonderful against "real fighters" too.
> 
> ...


Hi
It should be remembered that the equivalent type to the Lysander in the Luftwaffe was the Henschel Hs 126 and in the USAAC it was the North American O-47. All would have been poor against fighters, indeed it could be argued that the Lysander was the 'best' of the three while the O-47 was probably one of the worst aircraft for the role possible! Exactly what was the US Army thinking?

Mike


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## Shortround6 (Jan 20, 2022)

MikeMeech said:


> Hi
> It should be remembered that the equivalent type to the Lysander in the Luftwaffe was the Henschel Hs 126 and in the USAAC it was the North American O-47. All would have been poor against fighters, indeed it could be argued that the Lysander was the 'best' of the three while the O-47 was probably one of the worst aircraft for the role possible! Exactly what was the US Army thinking?
> 
> Mike


At least the US Army wasn't thinking the O-47 could do ground strafing and light bombing.

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## Peter Gunn (Jan 20, 2022)

MikeMeech said:


> Hi
> It should be remembered that the equivalent type to the Lysander in the Luftwaffe was the Henschel Hs 126 and in the USAAC it was the North American O-47. All would have been poor against fighters, indeed it could be argued that the Lysander was the 'best' of the three while the O-47 was probably one of the worst aircraft for the role possible! *Exactly what was the US Army thinking?*
> 
> Mike


Call me crazy but probably that they needed a new observation plane to replace the old canvas covered biplanes they had.

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## Thumpalumpacus (Jan 20, 2022)

BiffF15 said:


> Greg,
> 
> Being able to fly slow is a strength, however if your opponent is markedly faster and more maneuverable it relegates one to strafe rag status in the case of a Lysander versus a 109.
> 
> ...



That OV-10 v F-16 video we discussed a couple of months ago comes to mind.

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## Shortround6 (Jan 20, 2022)

MikeMeech said:


> Hi
> It should be remembered that the equivalent type to the Lysander in the Luftwaffe was the Henschel Hs 126 and in the USAAC it was the North American O-47. All would have been poor against fighters, indeed it could be argued that the Lysander was the 'best' of the three while the O-47 was probably one of the worst aircraft for the role possible! Exactly what was the US Army thinking?
> 
> Mike


The progression of the "observation" class aircraft might be a subject all on it's own. It lasted a bit over 20 years and a LOT of different aircraft and it was an essential part of any air force, until it wasn't, really quickly.


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## MikeMeech (Jan 20, 2022)

Peter Gunn said:


> Call me crazy but probably that they needed a new observation plane to replace the old canvas covered biplanes they had.


Hi
As did the Lysander and Hs 126:








Then we have the O-47:




This was the largest and heaviest of the trio, originally a three-seater, later it is reported to fly with a pilot and observer/photographer, the latter had to do his work from the belly of the aircraft. If used as a two-seater he would have to get back up to use the defensive MG if attacked, at least the observer of the Lysander and Hs 126 were close to their gun while observing. 

Mike

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## Shortround6 (Jan 20, 2022)

I have opened up a new thread for observation planes

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## nuuumannn (Jan 23, 2022)

tomo pauk said:


> The supercharger _drive_ on the DB 601 was better than that of the Merlin III. The S/C itself - probably not. On 87 oct, Merlin was making better power from 15000 ft up, granted the advantage was not a big one. The 100 oct fuel that allowed for greater boost at lower altitudes, meaning now that Merlin III was making better at alltitudes.



Interesting, thanks. The British could not take full advantage of that however, as the Germans largely had the high ground on their approach to the UK.



tomo pauk said:


> Emil will cruise high and fast due to having a lot of altitude and speed when making the landfall at the SE English coast. Spitfire does not have that luxury, it's modus opearndi was to scramble as fast as possible to beet the threat head-on, if possible.
> Not every Emil was armed with cannons, the E-1 was armed with 4 LMGs; granted LW was trying to up-gun those during 1940.
> Bf 109E-1 was delivered in 1056 copies by 30th June 1940, with another 405 to be delivered until end of February 1941. E-3: 1198 copies until end of July 1940. E-4: 185, plus 609 to be delivered until end of January 1941.



Yes, but the point was still the same, the addition of cannon to those Bf 109s that did proved a bonus, also, there were Spitfires that only had two-position props (until retro-fitted with full CS props) versus the Bf 109's fully variable props, which again states that both aircraft had advantages and disadvantages over each other. In 1939 this made a big difference and affected performance.


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## tomo pauk (Jan 23, 2022)

nuuumannn said:


> Yes, but the point was still the same, the addition of cannon to those Bf 109s that did proved a bonus, also, there were Spitfires that only had two-position props (until retro-fitted with full CS props) versus the Bf 109's fully variable props, which again states that both aircraft had advantages and disadvantages over each other. In 1939 this made a big difference and affected performance.



Your point was that 'Emil has cannon armament'. That was not exactly the case, since hundreds of Emils were with LMGs only.
Bf 109s were not fighting Spitfires in 1939, that were _faster_ than the Bf 109E despite the fixed prop or the 2-speed on the Spitfire.


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## nuuumannn (Jan 23, 2022)

GregP said:


> think it was the other way, with the Bf 109E slats helping the Emil hang in there in turns, even if stalled, and the Spitfire being better at medium to high speeds, when the Bf 109E controls got too heavy to be of much use.



Nope, not according to pilots who flew the types. It's well known that the British fighters were superior low speed dogfighters. The Bf 109E could not out turn the Spitfire, nor could it out turn the Hurricane. The problem the slats created was that they tended to snap out asymmetrically when in a tight turn, which disrupted airflow over the ailerons causing snatching of the ailerons and when this happened it made aiming difficult for the Messerschmitt pilot and following through more difficult for the German.

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## nuuumannn (Jan 23, 2022)

Thumpalumpacus said:


> Anyone looking to read about this further should read William Shirer's _The Third Republic_, a history of that era of French history.



Thanks man, I'll look into that. Shirer is a very thorough author; his account of the Third Reich is still the benchmark.

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## nuuumannn (Jan 23, 2022)

tomo pauk said:


> Your point was that 'Emil has cannon armament'. That was not exactly the case, since hundreds of Emils were with LMGs only.



Okaaaaay, but some _did_ have cannon, just like some Spitfires had two-position props and some didn't... So my point still applies.

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## Thumpalumpacus (Jan 23, 2022)

nuuumannn said:


> Thanks man, I'll look into that. Shirer is a very thorough author; his account of the Third Reich is still the benchmark.



His history of France in that book, ranging from the Dreyfus Affair to the 1940 collapse, is just as detailed.

He doesn't touch on their wonky battleships of ugly airplanes, though.

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## nuuumannn (Jan 23, 2022)

Thumpalumpacus said:


> He doesn't touch on their wonky battleships of ugly airplanes, though.



I'd really like to read a history of these things. They are slightly fascinating, mind you, I'm fascinated by this, so that explains my intrigue...





DSC_0049

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## Thumpalumpacus (Jan 23, 2022)

nuuumannn said:


> I'd really like to read a history of these things. They are slightly fascinating, mind you, I'm fascinated by this, so that explains my intrigue...
> 
> View attachment 655571
> DSC_0049



I just want to know who designed this:






... thinking it was a good idea. It looks like a hotel having 'roid rage.

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## SaparotRob (Jan 23, 2022)

Looks like a self propelled prison island.

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## BiffF15 (Jan 23, 2022)

Thumpalumpacus said:


> I just want to know who designed this:
> 
> View attachment 655572
> 
> ...


Little Greta Thunberg would have a literal cow if she saw that...

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## Thumpalumpacus (Jan 23, 2022)

BiffF15 said:


> Little Greta Thunberg would have a literal cow if she saw that...



Or maybe a littoral cow?

Sorry, I'll grab my coat.

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## SaparotRob (Jan 23, 2022)

That was wonderfully awful.

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## Thumpalumpacus (Jan 23, 2022)

SaparotRob said:


> That was wonderfully awful.



Who doesn't love a good pun? C'mon.

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## nuuumannn (Jan 23, 2022)

Thumpalumpacus said:


> ... thinking it was a good idea. It looks like a hotel having 'roid rage.



Those are reall cool! I really like that "Tumblehome" look of 19th Century French battleships. It reminds me of this for some reason...

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## Thumpalumpacus (Jan 23, 2022)

nuuumannn said:


> Those are reall cool! I really like that "Tumblehome" look of 19th Century French battleships. It reminds me of this for some reason...




Great for floating stably, until you're punctured. Then your list goes to Hell and gone.

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## nuuumannn (Jan 23, 2022)

Thumpalumpacus said:


> Then your list goes to Hell and gone.



Pretty much. The Bouvet was sunk by a mine during the Dardanelles and the Henri IV was shelled attacking Turkish forts. Odd stern on that one...









French battleship Bouvet - Wikipedia







en.wikipedia.org













French battleship Henri IV - Wikipedia







en.wikipedia.org

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## PAT303 (Jan 23, 2022)

nuuumannn said:


> Nope, not according to pilots who flew the types. It's well known that the British fighters were superior low speed dogfighters.


Jeffery Quill stated after flying an Emil that RAF pilots gave it too much respect, it couldn't turn anywhere near as tight as a Spit or Hurri and the controls started locking up above 350mph and at 400 the ailerons were unmovable.

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## nuuumannn (Jan 23, 2022)

PAT303 said:


> it couldn't turn anywhere near as tight as a Spit or Hurri and the controls started locking up above 350mph and at 400 the ailerons were unmovable.



Pretty much. In later versions this was the case too. Those slats were effective in delaying the stall but they did nothing for the type's manoeuvrability. The Bf 109 was superior in the vertical plane to the British fighters.


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## Shortround6 (Jan 23, 2022)

nuuumannn said:


> versus the Bf 109's fully variable props



I could be wrong but think the early 109 props were fully variable but not constant speed?
The required the pilot to keep twitching the switch to adjust the prop to suit the speed range the plane was operating at? 
Or rather the pilot would have to keep the engine speed and the prop aligned with what he was trying to do. 

Trying it again 

If the Pilot was climbing (low speed but high power) the pilot would have to throttle the engine up but put the prop into fine pitch or close to it (coarser than take off).
If cruising the pilot had to throttle back but manually adjust the prop pitch to suit the throttle and desired speed. 
If at full speed you had max throttle and max pitch. 
But if you were a turn as the airplane lost speed the pilot would have to reduce the prop pitch with one hand while controlling the plane with the other hand while leaving the throttle alone (?). 



CS prop took care of that for the pilot. Somewhat.
Like in the turn the constant speed governor would automatically to reduce the pitch of the propeller to keep the prop pitch at a good match to aircraft speed as the engine was making full power. 

This is something often ignored with the 2 speed prop.
In order to get "best" performance the airplane with a two speed (basically one speed/fixed pitch after take-off)
the pilot had to reduce the engine throttle to keep from over speeding the prop. The prop is not operating at anywhere near a good angle if the airspeed in not near full speed and unless the engine is throttle reduced and the engine rpm reduced. Trying to fly a tight turn with the engine running around 20-30% below max power is obviously going to affect the planes turning ability.


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## pbehn (Jan 23, 2022)

PAT303 said:


> Jeffery Quill stated after flying an Emil that RAF pilots gave it too much respect, it couldn't turn anywhere near as tight as a Spit or Hurri and the controls started locking up above 350mph and at 400 the ailerons were unmovable.


It had cannon and was quick, with a good rate of climb. If you are diving at 400MPH you are leaving the bomber formation that you were sent to attack?

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## nuuumannn (Jan 23, 2022)

Shortround6 said:


> I could be wrong but think the early 109 props were fully variable but not constant speed?



Yes, that's why I said fully variable (as opposed to two-position) and _not_ CS. De Havilland fitted the first CS prop to a Spitfire in mid 1939.

I know you like to make a big deal out of the Brits fitting big hunks of wood to their fighters in the late 30s, and for good reason - it's inexplicable, really, considering that the Blenheim, Battle, Defiant, Whitley, Wellington, Sunderland, Hampden all had VP props before the Spitfire and Hurricane, but the Brits had them, they just didn't fit them to the aircraft that probably needed them as much...

I do know how props work. I used to work in a prop overhauling shop and marvelled at the simplicity of the Hydromatic props. Overhauled a couple off a DC-3, and hacked a set of HS blades for an Allison going into a Yak-3 from blades that had come from a Privateer. I've still got the tips I cut down on my shelf.

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## Clayton Magnet (Jan 23, 2022)

nuuumannn said:


> know you like to make a big deal out of the Brits fitting big hunks of wood to their fighters in the late 30s, and for good reason - it's inexplicable, really


Spitfires with wooden fixed pitch props were a little faster than the constant speed equipped units. The benefits of the conversion of course enormously outweigh the slight reduction in top speed.


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## nuuumannn (Jan 23, 2022)

Clayton Magnet said:


> Spitfires with wooden fixed pitch props were a little faster than the constant speed equipped units. The benefits of the conversion of course enormously outweigh the slight reduction in top speed.



Not to mention more efficient acceleration, better fuel consumption, better power usage across the range of the flight regime, the advantages certainly outweighed maximum speed. Nonetheless, it was recognised before the war that VP props were more efficient on the fighters, but production and supply was not what it would eventually become. The British industry was working at peacetime levels when the First Spitfires and Hurricanes entered service.


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## Shortround6 (Jan 23, 2022)

You know but some of our readers do not. 

Like saying the the 2 pitch prop would give about the same speed as the CS prop. It would but a Spitfire I CS could cut around 3 minutes or more in the time to 20,000ft. 
Going from 11. 3 minutes to 7.7 minutes for that climb is a major change. 
Like wise the change in work load for the pilot while in combat may be significant.

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## Greyman (Jan 23, 2022)

Shortround6 said:


> Like wise the change in work load for the pilot while in combat may be significant.



I've always said that a lot is made of the Spitfire I vs. 109E re: fuel injection and engine cutting (easy to explain to the casual reader/viewer in a couple of sentences) -- but I'd *much* rather have a constant speed prop and no fuel injection (Spitfire I) than the opposite (109E).

As the Luftwaffe report on the Hurricane and Spitfire said; _'Both types are very simple to fly compared to our aircraft, and childishly easy to take-off and land.'_ This really matters in a war where you don't have time to train a large cadre of expert pilots.

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## nuuumannn (Jan 23, 2022)

As mentioned earlier, the earliest Emils had the VP switch on the instrument panel, which meant that changing prop pitch was a juggling act that required moving hands about the cockpit, either taking one's hand off the power lever or off the joystick; either way the pilot has to think and act fast in the heat of combat. Sensibly, in later Emils, not sure what production batches or so forth, it was put next to the power lever.


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## pbehn (Jan 23, 2022)

nuuumannn said:


> Not to mention more efficient acceleration, better fuel consumption, better power usage across the range of the flight regime, the advantages certainly outweighed maximum speed. Nonetheless, it was recognised before the war that VP props were more efficient on the fighters, but production and supply was not what it would eventually become. The British industry was working at peacetime levels when the First Spitfires and Hurricanes entered service.





Clayton Magnet said:


> Spitfires with wooden fixed pitch props were a little faster than the constant speed equipped units. The benefits of the conversion of course enormously outweigh the slight reduction in top speed.


Fitting of CS props was an issue, which one do you fit? Obviously for the British it had to be made in UK, that is why ROTOL was formed. Then there is the question of what is it designed for? Between the declaration of war and the Battle of Britain the Merlin increased its power output by a huge amount. Any CS prop optimised for a Hurricane with 85 Octane fuel would need to be replaced by one optimised for 100 Octane. The LW noticed the improvement of the Spitfire MK II when introduced but at the end of the BoB the high altitude Jabo raids found that the Spitfire MkI was the best to counter them.


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## Shortround6 (Jan 23, 2022)

I have read (could be wrong) that one thing flight leaders tried to do in the first few flights over the French bases with new pilots to see how they were handling the prop pitch switch.
This was before trying to fly over England. 
It the switch was not adjusted properly sometimes the new pilots could not maintain formation. And sometimes even they could maintain formation they were using a wrong throttle and pitch combination that used up fuel faster than it should have. 

Granted a British pilot could set the CS control wrong also (and we know that P-38 pilots weren't using the right combinations at times

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## nuuumannn (Jan 23, 2022)

pbehn said:


> Fitting of CS props was an issue, which one do you fit? Obviously for the British it had to be made in UK, that is why ROTOL was formed.



True, but De Havilland props were based on Hamilton Standard props. Availability is also an issue, rapidity of production to meet needs. British military expansion in the late 1930s was rapid for an industry used to peacetime and not every company was able to keep up with Air Ministry production orders, which meant delays.

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## Shortround6 (Jan 23, 2022)

pbehn said:


> Fitting of CS props was an issue, which one do you fit? Obviously for the British it had to be made in UK, that is why ROTOL was formed. Then there is the question of what is it designed for? Between the declaration of war and the Battle of Britain the Merlin increased its power output by a huge amount. Any CS prop optimised for a Hurricane with 85 Octane fuel would need to be replaced by one optimised for 100 Octane. The LW noticed the improvement of the Spitfire MK II when introduced but at the end of the BoB the high altitude Jabo raids found that the Spitfire MkI was the best to counter them.


I am not sure it works that way? Maybe one of our experts can get in on this.

A CS prop is set up to run at a certain pitch at a certain air speed/altitude. The Rotol props (at least the early ones) would handle 35 degrees of pitch change? 
Actually the prop should be set to run a certain speed at a certain pitch and hopefully it should be correct at hi speed once the prop has changed pitch? 
Now at 17,000ft or so there shouldn't have any change in the pitch settings as the Merlin and XII should have been making the same power at the same rpm at that altitude. 
Unless they adjusted them for the difference in speed due to antennas and other items that produced drag. 

I could be way wrong but think the idea of the CP propeller was to let the the prop advance the pitch as long as the engine was making the set rpm. 
If the engine was making more power (higher boost) then the prop would advance the pitch change until the prop couldn't advance the pitch anymore. 
Your top speed is the same but with the higher boost you are going to get their quicker. 

Now if you are doing a higher speed at lower altitude than you used to do because of the higher boost were does that fall on the propellers pitch range? 
does 335mph at 10,000ft call for more pitch change than 320mph at 10,000, I would say yes, but if your prop hasn't maxed out it's pitch range because the prop does have to give you a enough pitch to allow for 350mph (+) at 18,000ft is it going to make any difference? Allow for a little bit if over pitch to the plane can dive as the pilot is throttling back. 

Now if you are putting a prop on a Hurricane instead of a Spitfire you may want different blades and/or you may want to adjust the prop pitch back a little bit because the Hurricane is never going to use the max pitch of the Spitfire.
Unless the Hurricane has enough to extra travel so it doesn't really matter. 

I could be way off.


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## FLYBOYJ (Jan 23, 2022)

Actually think of a CP propeller like the automatic transmission in a car except you have the ability to control at what RPM the transmission shifts into the next higher gear. At take off you're looking at a low pitch, high RPM and you want to watch manifold pressure, (especially if you're running a supercharger so you don't overboost). As you're climbing and picking up speed you'll pick a prop setting that will give you a good rate of climb at a given manifold pressure and RPM. I remember flying a T-34 and set up for 2500 RPM at 25" ("25 square") manifold pressure as I was climbing and starting to pick up speed. At cruise I remember looking at either "24 square" or 2300 rpm at 24" manifold pressure. 2600 rpm at 26" manifold pressure (max numbers) would eventfully get me to max indicated airspeed, which was something like 160 or 170 mph. If I was flying at a certain cruise and wanted to do maneuvers, I wouldn't touch the prop control as my prop governor was now keeping my numbers in place.

It's been at least 18 years since I've flown an aircraft on a regular basis with a CP prop. Maybe some of our other resident pilots can chime in, let me know if I'm out to lunch or verify my memory.

Wes?


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## FLYBOYJ (Jan 23, 2022)

Here's a great reference, start at page 12-5



https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/airplane_handbook/media/13_afh_ch12.pdf


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## FLYBOYJ (Jan 23, 2022)



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## Peter Gunn (Jan 24, 2022)

Thumpalumpacus said:


> I just want to know who designed this:
> 
> View attachment 655572
> 
> ...


*HEY!!!*

*DO NOT HARSH ON MY PRECIOUS FRENCH PRE-DREADS!!!*

*THEM'S FIGHTEN' WORDS SONNY... *





Remember, you're talking to a guy that thinks the Brewster Buffalo is stylish, yeah I know, but not even therapy has helped with that.

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## SaparotRob (Jan 24, 2022)

Peter Gunn said:


> *HEY!!!*
> 
> *DO NOT HARSH ON MY PRECIOUS FRENCH PRE-DREADS!!!*
> 
> ...



You tell 'em Bro'!

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## MikeMeech (Jan 24, 2022)

Shortround6 said:


> I am not sure it works that way? Maybe one of our experts can get in on this.
> 
> A CS prop is set up to run at a certain pitch at a certain air speed/altitude. The Rotol props (at least the early ones) would handle 35 degrees of pitch change?
> Actually the prop should be set to run a certain speed at a certain pitch and hopefully it should be correct at hi speed once the prop has changed pitch?
> ...


Hi
Information from the late 1930s before WW2 is available from the part work 'Aero Engineering', Volume I, in an article on 'The Variable Pitch Airscrew' by Flt-Lt. J W Bell, Service Manager, Airscrew Division, de Havilland Aircraft Co.:

























In 1938 the de Havilland CS prop was flying on the Bristol Perseus powered de Havilland Flamingo. In November 1938 the Rotol (ROlls-Royce/BrisTOL) CS propeller (Hele-Shaw-Beacham patents) was being used for the RAF's Long Range Development Unit Vickers Wellesleys, powered by Bristol Pegasus XXII engines (using 100 octane fuel), these props replaced the de Havilland (Hamilton) two-pitch type normally fitted. I believe the RAF initially prioritised bombers for CS (and two-pitch) props, the production lines of both Hurricanes and Spitfires were fitting CS props by the end of 1939, the alteration of de Havilland two-pitch to CS on the squadrons in mid 1940 was to convert the fighters that had been already delivered prior to the change (the change was possible and mentioned in the above attachment).

Mike

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## Mike Williams (Jan 24, 2022)

Shortround6 said:


> I have read (could be wrong) that one thing flight leaders tried to do in the first few flights over the French bases with new pilots to see how they were handling the prop pitch switch.
> This was before trying to fly over England.
> It the switch was not adjusted properly sometimes the new pilots could not maintain formation. And sometimes even they could maintain formation they were using a wrong throttle and pitch combination that used up fuel faster than it should have.
> 
> Granted a British pilot could set the CS control wrong also (and we know that P-38 pilots weren't using the right combinations at times


Oberleutnant Ulrich Steinhilper of III/JG 52 wrote of the difficulties new pilots found operating the Me 109 E's propeller:

_We began our climb almost immediately after take-off and he was constantly using the radio to ask us to slow down so that he could keep up. It was obvious that he wasn't manipulating the pitch control with the skill of the more seasoned pilots to produce the same power as our machines. We tried to tell him what to do on the radio but to no avail. Eventually, about half way across the Channel at 4,000 metres Kühle told him to leave the formation and return to base._ Ulrich Steinhilper & Peter Osbourne, Spitfire on my Tail, (Independent Books, Bromley, 1990), p.303.

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## Mike Williams (Jan 24, 2022)

Shortround6 said:


> CS prop took care of that for the pilot. Somewhat.
> Like in the turn the constant speed governor would automatically to reduce the pitch of the propeller to keep the prop pitch at a good match to aircraft speed as the engine was making full power.
> 
> This is something often ignored with the 2 speed prop.
> ...


 Spitfire I Aeroplane, AP 1565A

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## Wild_Bill_Kelso (Sep 26, 2022)

gordonm1 said:


> Greg's Airplanes and Automobiles on Youtube has a recent video on the P40.
> I don't know how to make the movie work here but a link is below.
> 
> 
> ...




I generally like that guy's videos but he went off the rails in this one IMO. The Merlin-engined P-40 was considered by the USAAF to be the only one which could contend with Bf 109 or MC 202 / 205. The top speed doesn't tell the story, the real issue was altitude. As others mentioned, Allison P-40s began to really lose steam somewhere between 12,000 - 16,000 ft (depending on the specific type). The ones that still had power at 16,000 ft sacrificed a lot of the beast like power that say, a P-40K had 5,000 ft lower.

The P-40F/L (merlin engine) had decent power at 20,000 ft and was in the game at 23-24,000. They could make 370 mph at 20,000 ft. That meant they could tangle with 109s an C.202 when used as top cover. This meant for example they could still turn into attacks guns blazing, which was the standard tactic when facing high flying 109s. And thanks to the two speeds, they still performed pretty well down low. All of the USAAF fighter squadrons in North Africa used P-40F/L, with the brief exception of some P-40Ks by one squadron of the 57th FG, just due to shortages. The British only equipped 2 squadrons with the F/L ("Kittyhawk II and IIA") and found when they tried to switch back to the Allison types, casualties increased dramatically. 

The merlin engined P-40 was definitely needed in the North African campaign and in fact it was probably the single most important fighter type from early 1942 through the end in Tunisia in June 1943. One of the major Axis bases, at Pantelleria just off shore of Tunisia, was actually 'captured' by the 325th FG. After that, into the Sicily campaign some of the better mark Spitfires and improved P-38s were arriving in some numbers. But the merlin P-40s were still being used as fighters through the Battle of Anzio (June 44). 

In the Pacific, they did also use some of the Merlin P-40s, but the Allison types were good enough and able to hold their own pretty well. In China for whatever reason, they seemed to dominate.

The P-40 was a deeply flawed aircraft with some excellent features. It was a well designed airframe and fairly aerodynamic (though nothing like the low-drag P-51). The Allison P-51 by the way did not do so well in air combat and did not compare at all to the P-40 on a mission for mission basis in China or in Italy, except (in the A-36 version) as a bomber. The P-40 was deemed too flawed to continue to use but extended teething issues with and / or relatively slow production / development of other US types meant that it remained in use far longer than planned, and it turned out to have features which made the aircraft able to survive combat and destroy enemy aircraft much better than it should have done. Which is why it remained in use, not just because there were no other options (there were).

The flaws were the altitude limitations and rate of climb, especially when fully loaded.

The advantages were:
Very good turn rate (on the Allied side, second only to the Hurricane and Spitfire, and various biplanes)
Excellent roll rate (second only to the P-51 and Fw 190, IIRC)
Good dive acceleration and high dive speed (fast enough in a dive to evade Zeros and Ki-43s, just barely enough to often if not always evade Bf 109s)
Trim tabs so it could still be controlled, albeit with some difficulty, at very high speed (making it easier to evade A6M and Bf 109 in dives in particular)
Moderately good range (better than Bf 109, MC 202, Spitfire and Hurricane, but not comparable to A6M, P-51, P-38 or F4U) meaning it could climb to altitude before combat and reach farther for strikes
Heavily armed
Strongly built (to withstand 10G) and pretty well armored
_Relatively_ reliable and easy to maintain (still temperamental as all warplanes were, but far less so than many other competing types, meaning it was available and in larger numbers than many other fighters in a given Theater.
Pretty effective at bombing and carrying a substantial bomb load - more than a lot of light and medium bombers.

All of that meant that pilots often survived engagements, and when they had a chance to attack enemy aircraft, they often destroyed them. This is why most pilots that flew them really liked them, whereas commanders and administrative people did not. It was not a plane of the early war but of the middle, and it played a very important role for US in Pacific, China / Burma / India, and North Africa, and a very important role for the British in North Africa, and for the Russians, all especially during late 1941 through early 1944. Really, the turning point of the war.

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## GrauGeist (Sep 26, 2022)

The RAF (and RAAF) used the Tomahawk in North Africa before receiving Kittyhawks.

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## Wild_Bill_Kelso (Sep 26, 2022)

GrauGeist said:


> I don't recall hearing that either and in a bit of irony, it was the .30 MG that jammed on Lt. Rasmussen's P-36, leaving him with only a .50 MG to engage the Japanese that morning at Pearl Harbor.



They did have significant problems with the wing-mounted .50 cal guns in the early P-40D and E (Kittyhawk I and IA), usually after pulling G. They made some changes which seemed to alleviate this substantially by around mid 1942, but it was largely understood that there was still a risk of the guns eventually seizing up if they were fired _while_ pulling G, which was sometimes done anyway. Some pilots described each gun 'packing up' one by one until they were all jammed.

The nose guns could jam too but far less often. The Tomahawk (P-40B/C) types had charging handles in the cockpit which allowed jammed guns to be recharged. The Kittyhawks were supposed to be equipped with electronic gun chargers that could be used to reset the guns if they jammed but these did not seem to work in practice.

Apparently by the time the P-40K came out the problems were substantially resolved.

My understanding is that all fighter aircraft with wing mounted guns had this problem to one extent or another. I know in the Middle East and in Australia they had the same issue with the 20mm Hispano. In Australia the problem with Spitfire Mk Vs was particularly severe and was also related to serious problems with their ammunition and with gun heaters.


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## Wild_Bill_Kelso (Sep 26, 2022)

GrauGeist said:


> The RAF (and RAAF) used the Tomahawk in North Africa before receiving Kittyhawks.



yes, and the SAAF as well, who got stuck with them the longest (into 1943 for at least one unit). In some ways the Tomahawks were better than the early Kittyhawks, as they were lighter so had a much better climb rate etc., but not after they started rating the engines for higher boost and RPM on the Kittyhawks.


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## Wild_Bill_Kelso (Sep 26, 2022)

I should clarify my earlier long post. P-40s were there from fall 1941. The first merlin engined P-40 started showing up in Mid 42 in small numbers in US units (squadrons from the 33rd then 57th FG) that were initially attached to existing British units that had been in the Theater for a while. Gradually the numbers were ramped up.


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## GrauGeist (Sep 26, 2022)

Something funny about my comment about the .30MG jamming on Rasmussen's P-36?


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## Thumpalumpacus (Sep 26, 2022)

GrauGeist said:


> Something funny about my comment about the .30MG jamming on Rasmussen's P-36?



As noted above, I think it was the irony that it wasn't the fifty that jammed.

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## Greg Boeser (Sep 26, 2022)

At least his had bullets! I think Thacker landed to find they had never removed the breach plugs from his guns.


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## GrauGeist (Sep 26, 2022)

Thumpalumpacus said:


> As noted above, I think it was the irony that it wasn't the fifty that jammed.


Perhaps my sense of humor is a bit strained as of late, but it still escapes me why it would be seen as funny.

I could see the fact that a Japanese aircraft was shot down by a guy wearing purple pajamas funny, sure.


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