# Could the P36 have become America's Zero?



## pinsog (Sep 14, 2013)

The P36 had very light wing loading, very good climb rate, and very good turn radius. It's engine was equal to or better than the Zero with more growth potential. What would have kept the P36 from becoming the US version of the Zero or KI43? Give it 2 syncronized Browning 50's and no other armament. Maybe a bit of pilot armor.

Thoughts?


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## gjs238 (Sep 14, 2013)

Self-sealing fuel tanks?


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## swampyankee (Sep 14, 2013)

I think that USAAF doctrine for its pursuit aircraft had already diverged too far from the supremacy of low wing loading, fast-climbing pure dogfighters exemplified by aircraft like the Zero.


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## pinsog (Sep 14, 2013)

Understand, I am not avocating replacing the F6F, F4U or P38. What I am suggesting is something to hold the line better than the F4F, P39 and P40. I'm not sure the P40 might have been a step back from what the P36 could have been had it retained it's radial engine and had the radial engine upgraded with some of the same upgrades the F4F recieved.


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## gjs238 (Sep 14, 2013)

How did the P36 compare to other R-1830 fighters?
P35, P66, F4F, etc?


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## davebender (Sep 14, 2013)

Fighter aircraft powered by the massive R2800 engine were in development pipeline during 1939. 

Building lightweight and inexpensive P-36 for sale to friendly nations such as Australia, Netherlands, China, Finland, Belgium etc. might be a good idea. However U.S. Army Air Corps would not settle for anything less then an over priced monstrosity such as P-47. It's the American way.


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## pinsog (Sep 14, 2013)

davebender said:


> Fighter aircraft powered by the massive R2800 engine were in development pipeline during 1939.
> 
> Building lightweight and inexpensive P-36 for sale to friendly nations such as Australia, Netherlands, China, Finland, Belgium etc. might be a good idea. However U.S. Army Air Corps would not settle for anything less then an over priced monstrosity such as P-47. It's the American way.



The R2800 fighters didn't show up in combat until mid-war, I'm talking about something to hold the line until those new, big engine fighters show up. The P36 had impressive turn and climb stats and with upgraded 1820's or 1830's shouldn't it have at least been comparable to the Zero in performance?


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## JtD (Sep 14, 2013)

The extra speed of the P-40 was a pretty good thing to have when going up against bombers. At altitude, a Ju 88 was about as fast as a P-36. The air war is not just about turn fights with A6M's. 

That said, the P-36C as it was was pretty close in it's characteristics to an A6M2, at least at low altitude. It was used by several nations in WW2, with limited success. But, as speed and firepower were more important than low speed turning, I think the P-40 did better than the P-36 would have done.


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## swampyankee (Sep 14, 2013)

The P-36 could certainly have had significant performance improvements, simply due to increased engine power. I suspect, too, that it could do with a bit of aerodynamic clean-up, especially with regards to its engine installation. It is, of course, more difficult to design a good air-cooled engine installation than that of a water-cooled in-line, but it's certainly possible to design a clean engine with a radial. Compare the zero-lift drag coefficient of the F4U and that of the Bf109. The latter was reportedly about 0.029, or about 30% greater than the Corsair's.


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## Rufus123 (Sep 14, 2013)

P-36's got credit for two victories at Pearl. 

I thought the Wildcat did hold the line well until better things came along. Not as much of a dog as some people say it is.


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## davebender (Sep 14, 2013)

Apples and oranges.

P-36 is an Army land based fighter aircraft. Historically replaced by P-40.
F4F is a CV based fighter aircraft. Historically replaced by F6F.
.....USMC land based F4Fs muddy the distinction a bit. However if given a choice (and similar engines) the Jar Heads might prefer P-36 over F4F when operating from Guadalcanal.


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## pinsog (Sep 14, 2013)

davebender said:


> Apples and oranges.
> 
> P-36 is an Army land based fighter aircraft. Historically replaced by P-40.
> F4F is a CV based fighter aircraft. Historically replaced by F6F.
> .....USMC land based F4Fs muddy the distinction a bit. However if given a choice (and similar engines) the Jar Heads might prefer P-36 over F4F when operating from Guadalcanal.



F4F and P36 have similar top speed, P36 climbs at 3400 fpm, F4F around 2000 fpm. I'd give P36 2 synchronized 50's and remove the rest so F4F would have firepower, P36 would easily out turn F4F and P 36 should easily have altitude performance over F4F. Maybe they could both be deployed and compliment each other. P36 takes on fighters, F4F goes against dive bombers and 2 engined bombers. 

How much weight would self sealing fuel tanks add to P36?


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## pattle (Sep 14, 2013)

It sounds as though an improved P36 is being suggested in this thread as an aircraft that may have been able to match the Zero at it's own game, if this is the case then maybe it could have done as it wasn't bad plane. I think it was a better plan to build planes like the P40 that instead of trying to beat the Zero at its own game played a different game that the Zero was forced to join in with.


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## The Basket (Sep 14, 2013)

Not the Zero. By 1942 Zero was a poor performer.
No point copying that.
The P-36 was certainly good for its day. But Spitfire was better.
Maybe a better rationale is that America should build a fighter that can match the Spitfire since it was plenty good.

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## GrauGeist (Sep 14, 2013)

Once you start adding heavier/additional firepower, improved armor and self-sealing tanks, your performance declines. To overcome the penalty, modifications would have to be made such as larger engine, aerodynamic modifications and such. This would take time to figure out and implement and now you're into the time-frame where the newer designs were starting to appear.

One of the reasons why the A6M was successful early on, is because it didn't need self-sealing tanks or armor. This over-confidence cost them dearly when they eventually came head to head with U.S. built aircraft.


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## davebender (Sep 14, 2013)

Me-109 was also better. That makes no difference as USA was not going to build Spitfires and Me-109s. 

This is essentially a contest between improving the radial engine P-36 and morphing the aircraft into V12 powered P-40.


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## The Basket (Sep 14, 2013)

I want an aircraft with armour. And doesnt burst into flames. Or fall apart.

Just saying copy the best. The Zero was unknown anyway so the P-40 was a Spit/109 copy as the v12 was the speed king. If you want maneuverability then go biplane and put some fixed undercarriage on there too.


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## Shortround6 (Sep 14, 2013)

Every P-36 built after fall of 1939 is a P-40 NOT built. They are built in the same factory, by the same workers, using much of the same jigs and fixtures. 

A very early P-40s fuel tanks weighed 171lbs. On a P-40B they went to 253lbs and on the P-40C they went to 420lbs which is about the weight they stayed except for the stripper models that pulled a fuel tank in which case the two reaming tanks weighed about 322lbs. P-40Bs Cs added 93lb of armor and BP glass, later P-40s added more. 

P-36 altitude performance is rather doubtful. It all depends on WHICH R-1930 engine you stick in. 

We have had a lot of threads on this. 

The engine used in the historic P-36s was the -17. 1200hp for take off but only 1050hp at 6500ft. single speed supercharger. The P-36B was experimentally fitted with a -23 engine with a different supercharger gear. While this engine would give 950hp at 14,300 ft take off power was cut to 1100hp. the engines weighed about 1403-1436lbs.

The two speed -33 engine as used in the P-66 and some early NON-turbo B-24s was good for 1200hp take-off, 1100hp at 6500ft in low gear and 1000hp at 14,300ft in high gear. The engine went about 1480lbs. This was aobut as good as it gets for a single stage R-1830 until rather late in the war. 

The engine used in the F4F was the -76 and had a two stage supercharger that gave 1200hp for take-off, 1100hp at 3500ft, 1050hp at 11,000ft and 1000hp at 19,000ft. this engine weighed 1550lbs _without_ intercoolers and ducts.

The engine used in the P-36s could be down to about 600 hp at 20,000ft making its climb rate at 20,000ft and above rather suspect.

As for going for _TWO_ .50 guns and pulling the wing guns? go for it. A single .50 weighs about 70-75lbs installed. three .30 cal guns weigh about 71-72lbs. .50 cal ammo weighs about 30lbs per 100 rounds. .30 cal ammo is about 6lbs per 100. or 200 rounds of. 50 cal ammo is worth 1000 rounds of .30 cal. 

Please note that a P-40B or C had 1040hp at over 13,000ft and had 22% less drag than a P-36. 

Synchronized .50 cal Brownings had a miserable rate of fire,some where between 400 and 500 rpm.


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## davebender (Sep 14, 2013)

If so then P-40 was a poor copy. Spitfire and Me-109 were superior in almost every way.


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## GrauGeist (Sep 14, 2013)

Bf109 and P-36 first flew in May 1935, Spitfire first flew the next year...

Each aircraft had thier own unique design qualities and it's hard to imagine how a person could come to the conclusion that the P-40 was a copy of the Spitfire and/or Bf109


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## The Basket (Sep 14, 2013)

Very easily. The P-36 was a radial.
Spitfire was a V-12 inline and was faster.
Maybe if you put an inline V-12 in the P-36 it would be faster.
Not saying the P-40 was a copy. Just the inline concept.
Glad you told me the Spitfire flew in 1936. Next you will tell me the Pope is Catholic.


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## GrauGeist (Sep 14, 2013)

The Basket said:


> Glad you told me the Spitfire flew in 1936. Next you will tell me the Pope is Catholic.


Always glad to be of help...by the way, the Pope is Roman Catholic...


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## Shortround6 (Sep 14, 2013)

The XP-40 was the 10th production P-36 pulled from the production line and refitted with the Allison engine. aside from the engine the other changes (landing gear doors, etc) were introduced slowly. 

Americans had used both radials and V-12s on several earlier aircraft, Including the P-30 airframe.






From Wiki:
"Three of the four P-30s were delivered to the 94th Pursuit Squadron at Selfridge Field in 1934. The first P-30A, by this time redesignated PB-2A (Pursuit, Biplace), made its maiden flight on 17 December 1935, with deliveries to service units starting on 28 April 1936. The last of the 50 PB-2As were completed by August that year."

Who is copying who? 

Notice the turbo charger in the picture 

The designers in the US knew full well that V-12 engines offered more _speed_ than identical power radials. That had been proved a number of times in the late 20s and early 30s on US planes using US engines. They didn't need to copy the "concept" from any foreign country and most foreign countries didn't need to copy it from the US. 

Climb rate, weight, reliability and a few other features were up for debate but the speed advantage was not.


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## pinsog (Sep 14, 2013)

The Basket said:


> Not the Zero. By 1942 Zero was a poor performer.
> No point copying that.
> The P-36 was certainly good for its day. But Spitfire was better.
> Maybe a better rationale is that America should build a fighter that can match the Spitfire since it was plenty good.



I guess no one told the Japanese the Zero was a poor performer. There was a squadron of Spitfire veterans from the BOB that were sent to Austraila and got their butt's handed to them by Zero's. The Spitfires that tangled with Zero's in 1942 didn't fair to well.


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## GrauGeist (Sep 14, 2013)

Two other prototypes of the P-36 were the YP-37 and the XP-42

In the YP-37, Curtiss installed a water-cooled Allison V-12 (V-1710) along with some modifications. But terrible visibility from the relocated cockpit and cooling problems led the design nowhere.

The XP-42 was addressing the drag problems of the radial by incorporating a longer cowling and a full spinner. This suffered cooling problems as well and though the aerodynamic improvements gave it a faster speed, the P-40 ended up being faster in the end.


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## bob44 (Sep 14, 2013)

pinsog said:


> What would have kept the P36 from becoming the US version of the Zero or KI43?



In a word or two. Army/Navy.
They wanted armor, self sealing fuel tanks, ect. This means more weight, less performance.


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## Ivan1GFP (Sep 14, 2013)

This idea would never fly. The aircraft described here would not meet the customer's requirements.

Consider that the P-40 followed the P-36 even though its maneuverability was considerably worse. The goal was a bit more speed to be comparable to the European fighters.

The USN also chose to go to the F4F-4 to replace the F4F-3 even though the -4 was considerably heavier and had much worse performance.

I believe it was Flatley who commented that although there was a great reduction in maneuverability from the -3 to the -4, it didn't make any significant difference since both types were so far below the A6M in agility.

- Ivan.


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## Rufus123 (Sep 14, 2013)

davebender said:


> Apples and oranges.
> 
> P-36 is an Army land based fighter aircraft. Historically replaced by P-40.
> F4F is a CV based fighter aircraft. Historically replaced by F6F.
> .....USMC land based F4Fs muddy the distinction a bit. However if given a choice (and similar engines) the Jar Heads might prefer P-36 over F4F when operating from Guadalcanal.



I only mentioned the F4 since it was called out by name. Perhaps the P-36 would have done better with the engine but I still thought the F4 did better than most people think and held the line until other planes came into service and was still useful after the fact. I also thought the problem with the P-40 was how it was used and not the plane itself?


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## Rufus123 (Sep 14, 2013)

pinsog said:


> I guess no one told the Japanese the Zero was a poor performer. There was a squadron of Spitfire veterans from the BOB that were sent to Austraila and got their butt's handed to them by Zero's. The Spitfires that tangled with Zero's in 1942 didn't fair to well.



I could be wrong but I thought the problem with the Spitfires was not the planes but that people tried to fight the Zero the same as they would a 109. I thought if they had used energy tactics and speed the Spitfire would have been successful?


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## GrauGeist (Sep 14, 2013)

The P-40 and Wildcat suffered losses until the pilots changed thier tactics against the Oscar and Zero. Once they changed thier tactics, the Japanese started experiencing losses.

Both the P-40 and Wildcat were rugged aircraft and could absorb the damage inflicted by thier adversaries and still remain in the fight.


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## Shortround6 (Sep 14, 2013)

The early P-40 may have not been that much worse in maneuverability than the P-36. And early P-40 (no letter) was about 15% heavier than a P-36 (?) or Hawk 75 with P&W engine ( some of the figures for the P-36 are a little unbelievable compared to the HAWK 75 factory brochure). A P-40E clean is about 40% heavier which helps explain where the maneuverability went ( those six .50 cal guns in part).

People would do well to remember that the P-36 had some initial troubles ( wing skin wrinkling for one) and may have gained a bit of weight on it's own had it stayed in production instead/in addition to, the P-40.

From Joe Baugher's web site; " . However, the new Curtiss fighters began to encounter an extensive series of teething troubles almost as soon as they reached the field. Severe skin buckling in the vicinity of the landing gear wells had appeared, dictating increased skin thicknesses and reinforcing webs. Engine exhaust difficulties and some weaknesses in the fuselage structure were also encountered. Despite both production line and field fixes, the P-36As were grounded again and again. At one time, the 20th Pursuit Group was down to six serviceable P-36As, and even these planes had to be flown under severe limitations on their speed, aerobatics, and combat maneuvers. "


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## JtD (Sep 15, 2013)

swampyankee said:


> The P-36 could certainly have had significant performance improvements, simply due to increased engine power. I suspect, too, that it could do with a bit of aerodynamic clean-up, especially with regards to its engine installation. It is, of course, more difficult to design a good air-cooled engine installation than that of a water-cooled in-line, but it's certainly possible to design a clean engine with a radial. Compare the zero-lift drag coefficient of the F4U and that of the Bf109. The latter was reportedly about 0.029, or about 30% greater than the Corsair's.


The 1200hp of the R-1830-17 as installed on the P-36C were pretty much end of the line for the engine. Instead of raw power (as in higher octane fuel, more boost), it would have needed a better supercharger to have this power available at higher altitude. This doesn't come for free, as pointed out elsewhere in the topic by shortround6 - it adds weight and costs space.
The F4U has a lower drag coefficient also because it has a larger reference area. The wing is nearly twice as big, so a 30% higher drag coefficient means 30% less total drag for the 109. You can't just take some coefficient, it means nothing.


pinsog said:


> I guess no one told the Japanese the Zero was a poor performer. There was a squadron of Spitfire veterans from the BOB that were sent to Austraila and got their butt's handed to them by Zero's. The Spitfires that tangled with Zero's in 1942 didn't fair to well.


That's not an aircraft problem, but a tactics problem. The AVG fought with their P-40's against A6M since early on, used proper tactics and was highly successful under bad operating conditions.


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## tomo pauk (Sep 15, 2013)

swampyankee said:


> The P-36 could certainly have had significant performance improvements, simply due to increased engine power. I suspect, too, that it could do with a bit of aerodynamic clean-up, especially with regards to its engine installation. It is, of course, more difficult to design a good air-cooled engine installation than that of a water-cooled in-line, but it's certainly possible to design a clean engine with a radial. Compare the zero-lift drag coefficient of the F4U and that of the Bf109. The latter was reportedly about 0.029, or about 30% greater than the Corsair's.



The 'late P-36' could also use a better layout of exhaust stacks, that would provide some additional thrust when compared with the historic one. As done on XP-42?
The two speed engine should add another boost in performance, the deletion of fuselage MGs and ammo providing more space neccesarry for next step, two stage engine - again as with XP-42?
The armament - 4 HMGs should do.

The Cd0 of the Bf-109 was between .0225-0.024, depending wheter it was F/early G, or E/late G?


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## The Basket (Sep 15, 2013)

pinsog said:


> I guess no one told the Japanese the Zero was a poor performer. There was a squadron of Spitfire veterans from the BOB that were sent to Austraila and got their butt's handed to them by Zero's. The Spitfires that tangled with Zero's in 1942 didn't fair to well.


 
You are right no one did tell the Japanese as they kept building them. A Zero against a Buffalo is ok but not against a Corsair. Considering that even the best Zero model was slower than a Spitfire I shows that.


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## varsity07840 (Sep 15, 2013)

JtD said:


> The 1200hp of the R-1830-17 as installed on the P-36C were pretty much end of the line for the engine. Instead of raw power (as in higher octane fuel, more boost), it would have needed a better supercharger to have this power available at higher altitude. This doesn't come for free, as pointed out elsewhere in the topic by shortround6 - it adds weight and costs space.
> The F4U has a lower drag coefficient also because it has a larger reference area. The wing is nearly twice as big, so a 30% higher drag coefficient means 30% less total drag for the 109. You can't just take some coefficient, it means nothing.
> That's not an aircraft problem, but a tactics problem. The AVG fought with their P-40's against A6M since early on, used proper tactics and was highly successful under bad operating conditions.



The AVG didn't fight against A6Ms. Their fighter opponents were Army Ki -27s and Ki-43s.

Duane


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## JtD (Sep 15, 2013)

To my knowledge, most of the opposition was IJA, but the IJN used China as a test bed for the A6M, and on occasion ran into the AVG. But at any rate, tactics against the Ki-43 are the same that work against the A6M.


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## swampyankee (Sep 15, 2013)

JtD said:


> The 1200hp of the R-1830-17 as installed on the P-36C were pretty much end of the line for the engine. Instead of raw power (as in higher octane fuel, more boost), it would have needed a better supercharger to have this power available at higher altitude. This doesn't come for free, as pointed out elsewhere in the topic by shortround6 - it adds weight and costs space.
> The F4U has a lower drag coefficient also because it has a larger reference area. The wing is nearly twice as big, so a 30% higher drag coefficient means 30% less total drag for the 109. You can't just take some coefficient, it means nothing.
> That's not an aircraft problem, but a tactics problem. The AVG fought with their P-40's against A6M since early on, used proper tactics and was highly successful under bad operating conditions.



Please don't try to tell me how aerodynamic coefficients work. The F4U-1 had a slightly higher wing loading than the Bf109 and was a much larger aircraft. A lower wing loading will tend to decrease the value of zero-lift drag coefficient, so, if anything, the F4U was relatively cleaner than the comparison of Cd,0​ would show. Just about all single-engined fighters of WW2 had Cd,0​ between about 0.021 to about 0.025, whether using V-12s or radials, with no demonstrable superiority of one over the other, except for the Mustang, which was easily had the lowest Cd,0​ of any production WW2 combat aircraft.


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## Shortround6 (Sep 15, 2013)

Try looking at the actual drag and not coefficients. The drag of the P-36 was 22% higher than the prototype XP-40 in it's last configuration. That is computed by HP vs speed at a certain altitude but may not include exhaust thrust (about zero on a P-36) Later P-40s got worse, heavier and more bits and pieces sticking out or more holes creating turbulence. P &W got the difference down to 8% with their test mule (NOT the XP-42) but they _appear_ to be using exhaust thrust. The Test mule was an early P-40 (no letter) airframe and more than likely had no self sealing tanks, no armor and no guns making it very close in weight to the XP-40. 
Since ALL THREE aircraft used just about the same airframe except for engines and minor things like landing gear doors it is about the best comparison that I can think of, instead of trying to compare vastly different aircraft using coefficients.


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## JtD (Sep 15, 2013)

swampyankee said:


> Please don't try to tell me how aerodynamic coefficients work.


OK. If you don't want me to do it, you best ask someone else.


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## swampyankee (Sep 15, 2013)

I'm not going to argue that the P-36 was aerodynamically inferior to the P-40, just that the P-36 did not have as well-designed an engine installation as did many other radial-engined fighters, probably because it was one of the earlier ones, and did not get the kind of attention that was given to the F4F. The USAAF could have paid to put the P-36 into NACA's full-scale wind tunnel as was done with the F4F-3.


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## swampyankee (Sep 15, 2013)

JtD said:


> OK. If you don't want me to do it, you best ask someone else.



I've done that decades ago. I'm a recovering aerodynamicist.


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## Shortround6 (Sep 15, 2013)

swampyankee said:


> I'm not going to argue that the P-36 was aerodynamically inferior to the P-40, just that the P-36 did not have as well-designed an engine installation as did many other radial-engined fighters, probably because it was one of the earlier ones, and did not get the kind of attention that was given to the F4F.



And there you have it. NOBODY had well designed radial installations in 1936-41 compared to what was being done in 1942-45. They were working on it, and working on it hard but it took time and a lot of failed experiments to get on the right path. 
The timing for a _good_ radial engine installation is "just" too late to have any real effect for a _service_ aircraft in 1942 (FW 190 was the exception) To be in service in 1942 in numbers, it had to go into production in 1941 which means the design had to be finalized when in 1941? 

It wasn't just a bit of clean-up in a wind tunnel that helped the F4F, it is the fact that the 2 stage engine used offered 1000hp at 19,000-20,000ft compared to the 600-630hp that the engine in the P-36 supplied. 

A newer version of the two stage engine in the F4F did propel the P&W test Mule aircraft to over 380mph in the fall of 1942 but that is much too late to have any effect on the course of the war. 

We are getting into what ifs like "what if" Curtiss could have used the P-51 wing and radiator in 1938 on the P-40?

The XP-42 is a P-36 airframe and went through something like 13-14 different cowls and engines with extended shafts and short shafts while they worked on reducing drag for air cooled engine _WHILE_ still getting acceptable cooling. This all took time. Vultee tried the extended shaft engine and pointy nose on the first Vultee 48 (P-66) and had to give up on it. 

Everybody KNEW there was a drag problem. A number of people were spending time and money on solving it. They did solve it, just not in time for 1942.


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## pinsog (Sep 15, 2013)

Shortround6 said:


> And there you have it. NOBODY had well designed radial installations in 1936-41 compared to what was being done in 1942-45. They were working on it, and working on it hard but it took time and a lot of failed experiments to get on the right path.
> The timing for a _good_ radial engine installation is "just" too late to have any real effect for a _service_ aircraft in 1942 (FW 190 was the exception) To be in service in 1942 in numbers, it had to go into production in 1941 which means the design had to be finalized when in 1941?
> 
> It wasn't just a bit of clean-up in a wind tunnel that helped the F4F, it is the fact that the 2 stage engine used offered 1000hp at 19,000-20,000ft compared to the 600-630hp that the engine in the P-36 supplied.
> ...



What is the BEST performing/most powerfull P&W engine that could have historically been installed in the P36 in late 1941 or early 1942 in time for the P36 to see combat at say Midway and Guadalcanal? What is your best guess on the performance of the P36 with your historical engine of choice with 2 synchronized 50's for armament?


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## GrauGeist (Sep 15, 2013)

pinsog said:


> What is the BEST performing/most powerfull P&W engine that could have historically been installed in the P36 in late 1941 or early 1942 in time for the P36 to see combat at say Midway and Guadalcanal? What is your best guess on the performance of the P36 with your historical engine of choice with 2 synchronized 50's for armament?


You'd be better off getting rid of the syncronized cowl weapons...too low of a rate of fire. Four .50 or six .30 wing-mounted MGs would be a better choice.


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## pinsog (Sep 15, 2013)

GrauGeist said:


> You'd be better off getting rid of the syncronized cowl weapons...too low of a rate of fire. Four .50 or six .30 wing-mounted MGs would be a better choice.



I would normally agree with you, especially in the european theater, but against Japanese fighters and single engine dive bombers and torpedo planes I don't think it would have been too much of an issue. My school of thought is with the limited amount of engine power available in 1941 and 1942: I would rather have 2 50's and be behind the Japanese fighter, than have 4 or 6 50's and he is behind me. Also, the SBD Dauntless only had 2 synchronized 50's, I know it was a dive bomber, but still. (Does anyone know the rate of fire of the Dauntless's synchronized guns?)


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## GrauGeist (Sep 15, 2013)

The main consideration for a higher rate of fire is to deliver more damge in a short amount of time. In a confrontation, it's good to be able to "pump some lead" into the adversary, but he usually had a buddy nearby so inflicting the maximum amount of damage in the shortest possible time was a key factor in survivability.

While the Dauntless was capable of putting up a fight against the Japanese (much to thier surprise), many did not survive.


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## pinsog (Sep 15, 2013)

GrauGeist said:


> The main consideration for a higher rate of fire is to deliver more damge in a short amount of time. In a confrontation, it's good to be able to "pump some lead" into the adversary, but he usually had a buddy nearby so inflicting the maximum amount of damage in the shortest possible time was a key factor in survivability.
> 
> While the Dauntless was capable of putting up a fight against the Japanese (much to thier surprise), many did not survive.



Again, I agree 100% with what your saying, but until the Hellcat and P38 came out I think our fighters were overgunned for their horsepower. Also, it is hard to "pump some lead" into your enemy if he is always behind you do to superior performance. Or in the case of the raids on Darwin, your heavily armed P40 can't even climb high enough or go fast enough at that altitude to get to the enemy bombers. Many P39, P40 and F4F's didn't survive either.


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## swampyankee (Sep 15, 2013)

GrauGeist said:


> The main consideration for a higher rate of fire is to deliver more damge in a short amount of time. In a confrontation, it's good to be able to "pump some lead" into the adversary, but he usually had a buddy nearby so inflicting the maximum amount of damage in the shortest possible time was a key factor in survivability.
> 
> While the Dauntless was capable of putting up a fight against the Japanese (much to thier surprise), many did not survive.



I think that the USN's next-generation of attack aircraft, like the AD Skyraider and the AM Mauler, eschewed the gunner because of the resulting loss of performance and because they concluded that attack aircraft were, in general, too vulnerable to enemy fighters to manage without escort.


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## pinsog (Sep 15, 2013)

swampyankee said:


> I think that the USN's next-generation of attack aircraft, like the AD Skyraider and the AM Mauler, eschewed the gunner because of the resulting loss of performance and because they concluded that attack aircraft were, in general, too vulnerable to enemy fighters to manage without escort.



AND the US Navy had established 100% air supremacy by the end of the war with swarms of Hellcats and Corsairs escorting strikes, so they may have thought they would never be in a situation where the bombers needed to defend themselves.


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## Shortround6 (Sep 15, 2013)

I keep posting this picture. 







That is a picture of the Hawk 75 with TWO stage supercharger that was at the Army 1939 fighter trial. Please notice the duct/fairing under the plane about under cockpit. That is the fairing/duct for the inter cooler. 

There is no such thing as a free lunch, You want the power of the F4F up high you pay the cost in weight, bulk and drag, which hurts performance down low. 

The compromise is the single stage, two speed engine as used in the F4F-3A.

part of the problem with making an "American" Zero is that the Americans would never have bought an aircraft with the low structural strength of the Zero or it's low diving speed limit. The heavier structure means more weight so unless you _really_ cut armament or fuel you will wind up with a heavier airplane. 

As far as armament goes the two cowl 50s with 200rpg weigh about the same as six wing mounted .30 cal guns with 333 rpg ( 75% of the armament of a Hurricane I) that are firing almost 120 rounds per second instead of 15-16 rounds per second of the two cowl mounted .50s. Against the Japanese in 1942 who were using few or poorly protected fuel tanks and little, if any armor what does the .50 cal do for you?


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## pinsog (Sep 15, 2013)

Shortround6 said:


> I keep posting this picture.
> 
> View attachment 242960
> 
> ...



I despise RCM for fighters in WW2, BUT against the Japanese, I would say they would be acceptable if not VERY effective, especially against single engine fighters and dive bombers(Don't know how well it would work for the Betty)

P36 with the F4F-3A engine: either 2 50's or 6 30's, can you give a best guess on performance?

When I say "American Zero", it is the best way for me to characterize the P36 before we increased the weight by 30% or 40% and killed its climb rate and hurt its turning ability.


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## Shortround6 (Sep 15, 2013)

Your "despised RCM" seem to have worked moderately well for both the Germans and Japanese. The 109 E used two of them in cowl and it's 20mm guns ran out of ammo after about 8 seconds so the Germans did a fair amount of fighting with just the cowl guns. Same for the Zero, two rcmg in the cowl and two 20mm guns with just 55-60 rounds each in the wings. Quite a number victories after the cannon were empty. The Japanese army fighters in 1941/early 1942 used either two rcmgs or one rcmg and one 12.7. 
The Italian 12.7mm guns used explosive bullets that the US guns did not have. They also may have had a better rate of fire when synchronized. 

There is no reason I can think of that the Betty should be resistant to rcmg fire. One description has the ONLY armor on early versions as ONE piece about the size of a pancake protecting an ammo rack. The wing was practically one big fuel tank and NOT self sealing. Using a mixture of AP, tracer and incendiary ammunition multiple rcmgs should have little trouble setting it on fire. 

Speed is rather dependent on the cowling, the difference in armament may be minor (more drag with 6 guns?) but the fasted figure I have seen for a "service" radial engine Hawk is under 330mph. Climb is more dependent on weight and that depends on protection and structure more than armament, unless you go nuts and try to fit 4 or more .50 cal guns.


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## pinsog (Sep 15, 2013)

Shortround6 said:


> Your "despised RCM" seem to have worked moderately well for both the Germans and Japanese. The 109 E used two of them in cowl and it's 20mm guns ran out of ammo after about 8 seconds so the Germans did a fair amount of fighting with just the cowl guns. Same for the Zero, two rcmg in the cowl and two 20mm guns with just 55-60 rounds each in the wings. Quite a number victories after the cannon were empty. The Japanese army fighters in 1941/early 1942 used either two rcmgs or one rcmg and one 12.7.
> The Italian 12.7mm guns used explosive bullets that the US guns did not have. They also may have had a better rate of fire when synchronized.
> 
> There is no reason I can think of that the Betty should be resistant to rcmg fire. One description has the ONLY armor on early versions as ONE piece about the size of a pancake protecting an ammo rack. The wing was practically one big fuel tank and NOT self sealing. Using a mixture of AP, tracer and incendiary ammunition multiple rcmgs should have little trouble setting it on fire.
> ...



I certainly don't want to start a MG debate here, but I have often wondered if the reputation of American aircraft being tough was because the Germans and Japanese had run out of cannon rounds and sprayed them with RCM? 

Is the 330 mph figure for the Hawk with the best P&W engine at the time? Did it have a 2 speed supercharger or single speed? Was the F4F-3 engine more powerful or rated at a higher altitude?


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## Shortround6 (Sep 15, 2013)

That is part of it but thousands of aircraft were shot down with rifle caliber machine guns. They are not ideal by any stretch but the American .50 has a bit of an over blown reputation. While it was fairly effective as a gun it had one rather major draw back and that was it's weight, both of the gun and it's ammunition. While four of them, mounted int the wings, can certainly be fairly effective they are firing 48-52 rounds per second, not 15-16 rounds per second of two cowl mounted guns. 

To damage a plane, first you have to hit it and just two cowl mounted .50s don't have a very good hit potential. They are firing close to the number of projectiles per second as the 20mm cannon in the 109E or the Zero, except that each .50 cal projectile has much less effect than a 20mm projectile _on average._ Granted the .50 can fire longer.

I have given the figures of the for the P&W engines earlier. 

Basically you have around 1000-1050 at around 6500ft (most single speed engines) or 1000-1050 at 13,100ft ( two speed engines in high gear) or 1000hp at 19,000ft (two stage engines). There are some minor variations but not enough to get too excited about. There may have been something not quite right with the P&W single stage supercharger. Some engines were restricted to 2550rpm in high gear instead of the 2700rpm they could run in low gear. Changing to high grade fuels often wasn't used to change the power output but to raise the full throttle height. 


There is no real difference between the engine in an F4F-3 and a F4F-4. The -4 just gained weight. The early F4F-3 NOT having self sealing tanks or much for armor. 

I said "fasted figure I have seen for a "service" radial engine Hawk is under 330mph." they are usually in the 323-326mph range.


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## Greyman (Sep 15, 2013)

That seems pretty fast for a Hawk. Are the details of the test/test aircraft available?


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## Ivan1GFP (Sep 15, 2013)

JtD said:


> To my knowledge, most of the opposition was IJA, but the IJN used China as a test bed for the A6M, and on occasion ran into the AVG. But at any rate, tactics against the Ki-43 are the same that work against the A6M.



I don't believe this is entirely true.
The Ki-43 and A6M behaved quite differently:
The A6M was faster the Ki-43 in their equivalent versions. The last version of the Ki-43 was a touch faster but did it with cosiderably more horsepower.
The roll rate of the A6M degraded much worse than the Ki-43 as speed increased. Even at very low airspeeds, the roll rate of the Ki-43 was superior.
The armament was simply different. The A6M had cannons but had very little ammunition for them until the late war versions came out.

- Ivan.


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## pinsog (Sep 16, 2013)

Was the P36 ever flown head to head against the F4F Wildcat in a mock dogfight?


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## Jabberwocky (Sep 17, 2013)

Could the P36 have become America's Zero? - No

The P-36 was a delightful little aircraft and quite the dogfighter, but it never had the speed, rate of climb, range or altitude performance necessary to make it the kind of theater altering aircraft that the A6M did.

In 1940-1942 the Zero had several major advantages against its opponents. It was faster than the majority of them at medium to high altitudes, was more maneuverable than them at low to medium speeds, it climbed better than them across the altitude band and it generally had well trained and more combat experienced pilots. Its range was also a combat multiplier, allowing it to escort bombers or strike on its own without fear that its own bases (land or carrier) would be threatened.

The Zero's major opponents in the early war in the Pacific were the Hurricane and Buffalo with the RAF, the F4F and F2A-2/3s with the US Navy and the P-40B/C/E and P-39C/D with the USAAF. It also faced various Soviet types - predominately I-16s and I-153s - in early deployment testing.

Against this opposition it held all the cards in most forms of maneuvering combat. Any opponent that it couldn't out turn, it could easily outrun. Against the Western types, it could make tighter, faster circles and loops. It could out-climb them and actually accelerated as well as or better than most in a dive - the problem for the Zero not being dive acceleration, but limiting speed. 

It also had better altitude performance than all the Western types bar the F4F, which was roughly its equivalent above 20,000 ft. 

The P-36 had none of these advantages. It was probably as nice a dogfight aircraft as the early F2As, but lacked some of their pace. Both the Buffalo and the P-36 had problems hitting their advertised speeds. The French found their Hawk 75s with R-1820s had problems with engine cooling and oiling the limited their time at full power and imposed restrictions on combat maneuvers (such as going inverted and performing steep dives).

Lateral control, turning ability and roll rate was better than the Hurricane I or Spitfire I. However, the Spitfire, with a 30-40 mph speed advantage at most heights, could engage or disengage combat at will, meaning that the pilot could dictate the fight.

This speed disadvantage is the key distinction between the P-36's potential and the A6Ms potential. Without at least parity in speed, the P-36 is going to suffer against first line opposition like the Bf 109 or A6M.

What you'd see is what happened to the A6M. Once it lost that speed parity as newer fighters entered the Pacific theater (P-38, F6F, F4U ect) it quickly went from a hunter to a target.


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## swampyankee (Sep 17, 2013)

pinsog said:


> AND the US Navy had established 100% air supremacy by the end of the war with swarms of Hellcats and Corsairs escorting strikes, so they may have thought they would never be in a situation where the bombers needed to defend themselves.



While it's true that the USN had established total air superiority by the time the AD and AM saw service, and these aircraft rarely faced fighter opposition in service, the design history of these aircraft, including the choice of a single seat, dated back to 1943. I also suspect that the USN and USMC aviators who were involved in writing the specs for these aircraft did not forget the days they didn't have air supremacy: they used OR and found that the gunners saved too few aircraft to justify their presence. It was, overall, more effective to escort the strike aircraft than to have gunners.

I think that operations research found something similar with the heavily armed USAAF bombers in Europe: without escort, the gunners could not save enough aircraft to justify their presence. Once long-range escorts were available, removing the ball gunner and the waist gunners from B-17s and B-24s would probably have resulted in fewer USAAF crew casualties. (Logic? a: the ball and waist gun installation and gunners probably added something on the order of a 1500 pounds to the aircraft's take off weight, which was probably something like 25% of the bomb load on a long mission, so removing these guns and their crew would permit fewer sorties for the same effect on target, which means that the Luftwaffe gets fewer targets, and the aircraft they shoot down have smaller aircrews, so even if the number of aircraft shot down increases, the total number of casualties is less, or, if the same number of sorties is flown, more targets can be selected or they can be hit more often, b: since the same number of escorts would be available, the escorts may be more effective. Clearly, this logic does not apply if escorts cannot be provided).

Again, the entire chain of logic depends on the availability of sufficient escorts. One of the changes the USN made to its carrier air groups pretty early was increasing the ratio of fighters to strike aircraft, probably because they had found they had over-estimated the effectiveness of the gunners.


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## Shortround6 (Sep 17, 2013)

The US had decided in 1940 that planes _without_ armor and self sealing tanks would be used as operational trainers. So ANY operational aircraft against the Japanese either carry that weight penalty or need the decision changed. 

The P-36 was built to a higher load (G) factor and so had a heavier structure. Later Zeros improves their dive speed by using thicker (heavier) wing skin panels. 

The American planes were cursed with the .50 cal MG. The Zero carried about 120kg of guns and ammo. the Ki 43 carried 70kg, the 109E carried 149kg, A P-40C carried over 230kg ( perhaps well over). There were experimental P-36s with two .50s and two .30s and two .50s and four .30s. Two .50 cal guns with 200rpg is 122kg. 

When you are designing a plane the payload was about 30% of the gross weight, give or take a few percent. Changing the gun/ammo load by 100kg could change the gross weight of the rubber (paper drawing) airplane by 300kg. ( heavier structure/larger wing/bigger landing gear,etc) It never quite works this practice because you have to pick an existing engine and other parts and not one scaled perfectly to the payload but that is the start of things. Once you have the plane built however, you cannot take out some of the payload AND the up-sized structure/landing gear, etc.

The P-36/Hawk 75 was never going to be as light as the Zero. It could have been improved a bit but like I keep saying, every P-36 built is a P-40 NOT BUILT. A P-40 with sensible armament and proper tactics should be able to counter the zero.


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## Mangrove (Sep 17, 2013)

Shortround6 said:


> Speed is rather dependent on the cowling, the difference in armament may be minor (more drag with 6 guns?) but the fasted figure I have seen for a "service" radial engine Hawk is under 330mph. Climb is more dependent on weight and that depends on protection and structure more than armament, unless you go nuts and try to fit 4 or more .50 cal guns.


 
The highest ever recorded level flight velocity for a service Finnish Hawk 75 equipped with a 1200 hp Wright Cyclone GR-1820-G205A was *439 km/h at 3505 meters*, i.e. 273 mph at 11500 feet. The same figure for a Finnish Hawk with 1065 hp Twin Wasp SC-G was *429 km/h at 1500 meters*, i.e 267 mph at 5000 feet.

According to a 1939 factory manual "Curtiss Hawk 75-A Pursuit Airplane", the maximum speed for a plane with a GR-1820-G205A was 323 mph (520 km/h) at 15100 feet. The (Finnish) State Aircraft Factory speculated with was flown by a plane without a radio or armament.


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## JtD (Sep 17, 2013)

At Boscombe Down the Cyclone model managed 300 mph at 15000 feet, the Twin Wasp 300mph at 10000 feet. Note the export Twin Wasp models used 87 octane fuel and produced only around 1050 hp whereas the Army P-36's Twin Wasp used 100 octane fuel with higher boost and got 1200 hp out of the engine. Low altitude performance therefore was significantly better, and top speed marginally higher.


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## Mangrove (Sep 17, 2013)

JtD said:


> Note the export Twin Wasp models used 87 octane fuel and produced only around 1050 hp whereas the Army P-36's Twin Wasp used 100 octane fuel with higher boost and got 1200 hp out of the engine.



The exported *1065 hp* Twin Wasps indeed used 87 octane fuel, but the Cyclones could utilise 90 octane fuel as per factory and Finnish specifications. However, the Curtiss manual rates the Twin Wasp S3C3-G as 1100 hp. Thus the difference between using 87 octane fuel and using 100 octane fuel was merely 35 hp at takeoff, 40 hp at the sea level and 50 hp when cruising (2200 r.p.m).



JtD said:


> Low altitude performance therefore was significantly better, and top speed marginally higher.



I doubt there was a major weight difference between a 1100 hp Twin Wasp using 100 octane fuel and a 1200 hp Cyclone using 90 octane fuel. I still have my doubts regarding the performance figures provided by the factory.


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## Shortround6 (Sep 17, 2013)

The weight difference is in the manual/sales brochure. However the Cyclone powered planes had a different cowl than the P &W planes and may have had a different drag. 

There are US Army test reports on the wwiiaircraftperformance web site which seem to show a pretty consistent top speed of around 290-295mph using the -17 engine ( Single stage, single speed with FTH of 6500ft.)

With the -23 engine (different gear ratio on the supercharger) speed seems to be about 316-318mph. But only one plane had this engine and it was converted back. Some of the Cyclone powered Hawks had 2 speed superchargers and had more power at 10-15,000ft than the majority of the P&W powered planes even if they had the same take-off power. 

The difference between the 1200hp 100octane fuel engines and the 1050hp hp 87 octane fuel engines wasn't that great at 15,000ft. Many of them used the same supercharger and one speed gear ratio and the extra power was only available at low altitudes. Supercharger just couldn't supply enough air at much over 10,000ft. 
For some reason many of these engines never got a WEP or even a "military" rating. they got a take-off rating at 2700rpm and a "normal" rating at 2550rpm. Looking at the power available from the P-36 propeller tests it seems as much power could be had at 2550rpm and a higher boost than 2700rpm and a lower boost. I don't know why the boost was limited at 2700rpm. Cooling problems?


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## Greyman (Sep 17, 2013)

I haven't looked too closely at the P36 data from wwiiaircraftperformance.com, but here is a collection of Hawk data I've come across to date.


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## Jabberwocky (Sep 17, 2013)

Very nice Greyman. I've never seen the British and Finnish figures before!

I'm in the early stages of building a database of performance for early war types (speed, climb and roll-rate). Any chance you could send me the raw data?


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## Greyman (Sep 17, 2013)

I can send the British data but the French and Finnish figures were merely typed to me over email and boards like this.


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## davparlr (Sep 17, 2013)

Shortround6 said:


> And there you have it. NOBODY had well designed radial installations in 1936-41 compared to what was being done in 1942-45. They were working on it, and working on it hard but it took time and a lot of failed experiments to get on the right path.
> The timing for a _good_ radial engine installation is "just" too late to have any real effect for a _service_ aircraft in 1942 (FW 190 was the exception) To be in service in 1942 in numbers, it had to go into production in 1941 which means the design had to be finalized when in 1941?


While I don't really disagree with you on what you have stated here, but I do think there were some very good, non-FW 190 radial installations prior to 1942. Certainly one was the Hughes H-1 which was nearly, according to my estimate, 100 mph faster at sea level than the only slightly bigger and heavier, but more powerful, Bf-109D. Now it was indeed a superb aerodynamically designed hand built aircraft with much effort in detail to reduce drag, but it had to have a very efficient engine housing. Also, I suspect a lot of engineering went into the nacelle design of the B-26 since speed was paramount. Lastly, the F4U which flew in 1940 was quite comparable to the Fw-190 in performance and was MUCH heavier and had a comparatively huge wing (60% larger). I do not believe there was much improvement in the engine installation as the F4U performance increase significantly, although I could be wrong. I think the significant increases in hp post 1942 made smaller items in drag reduction such as elliptical wings and mid mounted wings, and possible radial engine installation of minor importance.


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## davparlr (Sep 17, 2013)

Shortround6 said:


> A P-40 with sensible armament and proper tactics should be able to counter the zero.



I would agree.


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## Shortround6 (Sep 17, 2013)

davparlr said:


> While I don't really disagree with you on what you have stated here, but I do think there were some very good, non-FW 190 radial installations prior to 1942. Certainly one was the Hughes H-1 which was nearly, according to my estimate, 100 mph faster at sea level than the only slightly bigger and heavier, but more powerful, Bf-109D.



Some people estimate that Hughes was getting about 1000hp from his P&W R-1535 engine which gives him about 45-48% more power than a Bf 109D. He was using 100 octane fuel for the record run and getting much more power than a "stock" engine running on normal fuel. His engine may have been essentially unmodified but it was not running at factory power levels. Also in record setting form the Hughes aircraft had a 138-140 sq ft wing. 

AS for the F4U, depending on altitude it may have 300-400 more HP than the 190 and that is without water injection. The early F4Us did a lousy job with exhaust thrust though. 

When you change to the F4U-4 I don't know how much of the improvement is due to the more powerful engine, how much to better use of the exhaust thrust and how much may be due to a better engine installation or better engine , the "C" series engine in the -4 had much better finning and needed less airflow ( drag) for the same amount of cooling (cylinder head and cylinder barrel temperatures)


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## Jabberwocky (Sep 18, 2013)

There was a comment earlier in the thread that US fighters were "cursed" with the M2. This is something of an overstatement, but not too far off the mark. The M2 was heavy for a machine gun, thus not particularly efficient in terms of weight vs firepower. However, it was effective and adequate enough for the jobs it was called on to perform.

There was also a comment that the Zero's armament weight was only 120 kg. This figure is roughly correct, but I don't think it includes the full armament weight, such as ammo and mountings. 120 rounds of 20 x 72B and 1000 rounds of 7.7 mm would have weighed in at 75 kg. The Type 99-1s weighed 24 kg bare and about 27.5 kg installed. The Type 97 weighed 12.5 kg, installed. 

Thus, the actual armament weight for an A6M1 or A6M2 was more like 155 kg (75 + 55 + 25). 

This weight is really is only applicable for the early Zeros, the A6M1, A6M2, and some A6M3s. The Japanese willingly went with heavier but more effective weapons, and more ammunition, on the A6M3 onwards. 

According to the TAIC report on the Zero and competing USN fighters, the A6M Model 52 had a total installed armament weight of 493 lbs/224 kg - of which 101 kg/222 lbs is gun weight. They swapped the Type 99-1 for the more powerful Type 99-2, with higher velocity ammunition and upped the capacity from 60 to 100 rounds per gun. They also added another 200 RPG for the 7.7 mm cowl guns.

Against this, the USN fighters had the following ammunition weights:

F6F: 1076 lbs (120% more)
F4U: 1056 lbs (118% more)
FM-2: 753 lbs (53% more)


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## Shortround6 (Sep 18, 2013)

Jabberwocky said:


> There was a comment earlier in the thread that US fighters were "cursed" with the M2. This is something of an overstatement, but not too far off the mark. The M2 was heavy for a machine gun, thus not particularly efficient in terms of weight vs firepower. However, it was effective and adequate enough for the jobs it was called on to perform.



When you have a 2000hp fighter carrying a decent battery of .50 cal guns and ammo is one thing, when you have a 1000-1200hp fighter it is another thing. 



> There was also a comment that the Zero's armament weight was only 120 kg. This figure is roughly correct, but I don't think it includes the full armament weight, such as ammo and mountings. 120 rounds of 20 x 72B and 1000 rounds of 7.7 mm would have weighed in at 75 kg. The Type 99-1s weighed 24 kg bare and about 27.5 kg installed. The Type 97 weighed 12.5 kg, installed.
> 
> Thus, the actual armament weight for an A6M1 or A6M2 was more like 155 kg (75 + 55 + 25).



It doesn't include mounts but but 1000 rounds of 7.7mm ammo should be about 27-28kg. 120 rounds of 20 x 72B ammo at 200 grams per round is 24kg, _not including drums._ drums may be 10kg each? 

Weight of a total armament installation can run 20-40% more than just the guns and ammo, mounts, ammo boxes, chutes, chargers, gun heat arrangements local reinforcing, etc. 



> This weight is really is only applicable for the early Zeros, the A6M1, A6M2, and some A6M3s. The Japanese willingly went with heavier but more effective weapons, and more ammunition, on the A6M3 onwards.



They also went for a more powerful engine, or at least one with a 2 speed supercharger to even the power out at different altitudes. the Sakae 21 having almost 200hp more for take-off and as much power at 6000meters at the Sakae 12 did at 4200 meters. 



> According to the TAIC report on the Zero and competing USN fighters, the A6M Model 52 had a total installed armament weight of 493 lbs/224 kg - of which 101 kg/222 lbs is gun weight. They swapped the Type 99-1 for the more powerful Type 99-2, with higher velocity ammunition and upped the capacity from 60 to 100 rounds per gun. They also added another 200 RPG for the 7.7 mm cowl guns.
> 
> Against this, the USN fighters had the following gun andammunition weights:
> 
> ...



A P-40 L or early N with four .50 cal guns and 201 rounds per gun had a gun/ammunition weight of about 554lbs. A P-40E with full ammo boxes (1410 rounds for all six guns,235 per gun) was carrying 900lb + of guns and ammo, and that is the "curse". 

Six .50s are a pretty good battery and will be an "adequate" armament for most jobs _but_ you need a powerful engine to carry it. The early US fighters didn't have the engine power to pull it off. With four .50s you are trading firepower for performance and depending on the opposition it may be a good trade. but trying to cut weight below four .50s leaves the US with a real problem. A low rate of fire and a gun that depends on kinetic energy for effect. The US never developed (in WW II) explosive bullets or even high capacity incendiary bullets or used mixed belts with incendiaries only making up 40% of the belt. Two .50s as the 'fixed" armament for a fighter is not enough and two .50s with 200rpg is 125kg. another 50rpg is another 13.6kg.


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## davparlr (Sep 18, 2013)

Shortround6 said:


> Some people estimate that Hughes was getting about 1000hp from his P&W R-1535 engine which gives him about 45-48% more power than a Bf 109D.


My book “German Combat Planes” by Wagner and Nowarra states that the Bf 109D had a DB 600Aa engine of 910 hp. Wikipedia tends to agree. This is probably close to the Hughes stock R-1535 (as bragged by Hughes, although I am sure it was well tuned) engine running 100 octane. In addition, the Bf 109E-1 with the more powerful 1100 hp DB 601A was only capable of a sea level speed of 290 mph, or 60+ mph less than the H-1, an impressive performance for a radial engine aircraft of similar power. In addition, the H-1 flew seven and a half hours at a high power setting to achieve a cross country record. The engine installation was not only aerodynamically efficient but was also apparently thermodynamically efficient.



> He was using 100 octane fuel for the record run and getting much more power than a "stock" engine running on normal fuel. His engine may have been essentially unmodified but it was not running at factory power levels. Also in record setting form the Hughes aircraft had a 138-140 sq ft wing.


 This is true but I doubt it makes up for a 35% increase in airspeed.



> AS for the F4U, depending on altitude it may have 300-400 more HP than the 190 and that is without water injection. The early F4Us did a lousy job with exhaust thrust though.


Spitfire performance tests show the Fw 190A-3 had a SL max airspeed of 335 mph. The non-MW-50 or C-3 injection BMW 801D-2 engine generated 1700 PS (1677 hp).
http://www.wwiiaircraftperformance.org/fw190/fw190-a3-climb-speed-26-11-42.jpg

The F4U-1 with normal power (approx.. 1700 hp) had a SL max airspeed of 326 mph, or only 9 mph less. 
http://www.wwiiaircraftperformance.org/f4u/02155-level.jpg

The F4U-1 is a huge aircraft compared to the Fw 190A-3 with an empty weight being 2600 lbs greater than the 190 it had a previously mentioned much larger wing (see your comments regarding the impact of the H-1 wing). 

I don’t think the claim can be made that the Fw-190 engine installation was efficient and at the same time stating that the F4U-1’s was not.

While I think your general comment on the status of radial engine integration is correct, I do think there were a few very capable radial engine integration designers prior to 1942.


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## Shortround6 (Sep 18, 2013)

What date is “German Combat Planes” by Wagner and Nowarra? most of the books from the 90s and later seem to say the "D"s had Jumo 210s like the "C"s. And the 109, while small, was not the cleanest of airframes. 
The Hurricane I prototype did 253mph at sea level with a fixed pitch prop and the engine running at 2505rpm and 6lbs of boost. production planes with constant speed props but with a weight of over 3000kg could do about 263 at sea level using 880hp. A Spitfire I with a fixed pitch prop could do 295mph at 2,000ft with the Merlin running at 2370rpm and 6.4lbs boost. the 880hp rating is at 3000rpm and 6 1/4 lbs. Hughes may have had 33% more power in a smaller airplane. 

The H-1 did NOT fly 7 1/2 hours at a high power setting. It flew a number of hours at high altitude ( Hughes was on oxygen until in malfunctioned) to take advantage of a good tailwind, the altitude got the plane into air influenced by the jet stream. Hughes had piloted or co-piloted over a dozen commerical west to east airline flights and done one flight with Jackie Cochran's Northrop Gamma. to try to map or gain experience with these tailwinds. 

The high altitude flying on oxygen trick had been done by Benny Howard and the Mr Mulligan 4 place cabin monoplane in the Bendix air race. 

A Hawker Hurricane once did a flight that averaged 400mph, doesn't mean the plane could actually do it.

Take another look at the pictures of the H-1. There do not appear to be ANY cowl flaps or way of adjusting the airflow, Pretty normal for 1935/36 but unless these guys were _waaaay_ more advanced than the even the designers at the end of the war something is off. The cowl is either set up for max speed or some compromise. Long duration high power climbs may have been a problem. One long climb on a record run overloaded with fuel doesn't prove much as the plane could be climbed slowly watching the temperature gauge.


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## Juha (Sep 18, 2013)

In fact CUc-506 achieved 476km/h at 3500m (418km/h at SL). Source Ilmailu 11/89, see also Lentäjän näkökulma II p. 212 Picture 2 Graph 1. 
CUw-572 414km/h at SL and 436,5km/h at 2285m with over-rich and 394km/h at SL and 433,5km/h at 3570m with automix.

Juha


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## Mangrove (Sep 18, 2013)

Juha said:


> In fact CUc-506 achieved 476km/h at 3500m (418km/h at SL). Source Ilmailu 11/89, see also Lentäjän näkökulma II p. 212 Picture 2 Graph 1.


 
What is the primary source quoted by the Ilmailu magazine and Raunio on his book? What was the weight of the plane and rpm pressure of the engine? I have not seen such document nor does any of the documents (dated from 1939 to December 1942) I have copies of mentioned such velocities.


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## Juha (Sep 18, 2013)

Mangrove said:


> What is the primary source quoted by the Ilmailu magazine and Raunio on his book? What was the weight of the plane and rpm pressure of the engine? I have not seen such document nor does any of the documents (dated from 1939 to December 1942) I have copies of mentioned such velocities.



In his book Raunio only thanks the staffs of the Sota-arkisto, Keski-Suomen Ilmailumuseo and Suomen Ilmailumuseo. Not really sure how much time Raunio spent in those but P. Manninen and co helped him and they have gone through at least most of the AF material at what then was Sota-arkisto. And Raunio have had access to the archive of VL .

In his Ilmailu article he mentioned besides US and British materia Selostuksia ja käyttöohjeita CUc and CUw koneita varten. Valtion Lentokonetehdas 1942.

Juha


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## Mangrove (Sep 18, 2013)

Juha said:


> In his book Raunio only thanks the staffs of the Sota-arkisto, Keski-Suomen Ilmailumuseo and Suomen Ilmailumuseo. Not really sure how much time Raunio spent in those but P. Manninen and co helped him and they have gone through at least most of the AF material at what then was Sota-arkisto. And Raunio have had access to the archive of VL .


 
I have also browsed through the material at the Finnish National Archive and various museums but found no such document as stated before. I also think that Raunio's book is quite a typical example of a work of an amateur historian with no accurate references to sources used to produce the book.



Juha said:


> In his Ilmailu article he mentioned besides US and British materia Selostuksia ja käyttöohjeita CUc and CUw koneita varten. Valtion Lentokonetehdas 1942.


 
I have a copy of this manual and it does not contain any values recorded during the claimed CUc-506 test flight.


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## Juha (Sep 18, 2013)

Hello Mangrove
At the early part of the article Raunio writes:"...artikkelin lähdeaineistona on käytetty Valtion Lentokonetehtaan koelentotuloksia CUw-551:llä (alatyyppi A2...), CUw-557:llä (alatyyppi A6...) sekä CU:506:lla (typo in original text) (alatyyppi A4, Wright Cyclone)..." In fact self-clear butat least gives the subtypes.

Juha


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## davparlr (Sep 18, 2013)

Shortround6 said:


> What date is “German Combat Planes” by Wagner and Nowarra? most of the books from the 90s and later seem to say the "D"s had Jumo 210s like the "C"s.



Don't really know however the max speed quoted was 322 mph at 13k which is more in line with the 910 hp version verses than the 292 mph at 13k for the 640 hp Jumo. Also, the E-1 definitely had the 601A engine of 1100 hp and could only do 290 mph at SL. If you backed that down to 1000 hp, the difference would even be greater.



> And the 109, while small, was not the cleanest of airframes.



Yep, you are certainly right.



> The H-1 did NOT fly 7 1/2 hours at a high power setting. It flew a number of hours at high altitude ( Hughes was on oxygen until in malfunctioned) to take advantage of a good tailwind, the altitude got the plane into air influenced by the jet stream. Hughes had piloted or co-piloted over a dozen commerical west to east airline flights and done one flight with Jackie Cochran's Northrop Gamma. to try to map or gain experience with these tailwinds.



I don’t know about that. Hughes was not known for his conservative approach to flying, in fact, he liked to push the envelope. I am sure he was pushing that plane. I also do not know if we know what altitude was that he flew at. If he was not on O2 he was not in the jet winds.



> Take another look at the pictures of the H-1. There do not appear to be ANY cowl flaps or way of adjusting the airflow, Pretty normal for 1935/36 but unless these guys were _waaaay_ more advanced than the even the designers at the end of the war something is off. The cowl is either set up for max speed or some compromise. Long duration high power climbs may have been a problem. One long climb on a record run overloaded with fuel doesn't prove much as the plane could be climbed slowly watching the temperature gauge.



There is no doubt it was tuned to the high speed record but it was still an impressive performance and honored in the National Air and Space Museum.


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## VBF-13 (Sep 23, 2013)

GrauGeist said:


> While the Dauntless was capable of putting up a fight against the Japanese (much to thier surprise), many did not survive.


The Speedy-D (as it was affectionately called) was one overall crackerjack aircraft. Put to the secondary role of a fighter, I'd put it pretty much how you put it.


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## GrauGeist (Sep 24, 2013)

VBF-13 said:


> The Speedy-D (as it was affectionately called) was one overall crackerjack aircraft. Put to the secondary role of a fighter, I'd put it pretty much how you put it.


Swede Vejtasa was a prime example of what a determined pilot could do with the rugged SBD, though he wasn't the only one, he is the most notable example


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## wuzak (Sep 24, 2013)

With regards to the Hughes H-1 and the Bf 109D, was the latter armed an armoured? If so, stripping a few of those things may help close the speed gap.


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## wuzak (Sep 24, 2013)

Also, when Hughes set his record he was nearly 100mph behind the absolute record. He didn't have the horsepower of teh MC72, but nor did he have to lug around those whpping great floats!


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## Shortround6 (Sep 24, 2013)

wuzak said:


> With regards to the Hughes H-1 and the Bf 109D, was the latter armed an armored? If so, stripping a few of those things may help close the speed gap.



It is not so much a question of the weight (and 109Ds had no armor) as it is the drag. 







The Jumo powered planes had little or no exhaust thrust, a not very good radiator installation, partial wheel covers and semi retractable tail wheel (at best), a higher drag canopy, etc.


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## varsity07840 (Sep 24, 2013)

pinsog said:


> Was the P36 ever flown head to head against the F4F Wildcat in a mock dogfight?



Vichy French H-75s fought against F4F-4s in at the start of the North African invasion. My recollection is that it was a pretty even fight. If someone else mentioned this in previous posts, I apologize.

The closest example of an American A6M at the start of the war was the CW-21B. Light weight, no protection, fast climb.

Duane


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## swampyankee (Sep 27, 2013)

davparlr said:


> While I don't really disagree with you on what you have stated here, but I do think there were some very good, non-FW 190 radial installations prior to 1942. Certainly one was the Hughes H-1 which was nearly, according to my estimate, 100 mph faster at sea level than the only slightly bigger and heavier, but more powerful, Bf-109D. Now it was indeed a superb aerodynamically designed hand built aircraft with much effort in detail to reduce drag, but it had to have a very efficient engine housing. Also, I suspect a lot of engineering went into the nacelle design of the B-26 since speed was paramount. Lastly, the F4U which flew in 1940 was quite comparable to the Fw-190 in performance and was MUCH heavier and had a comparatively huge wing (60% larger). I do not believe there was much improvement in the engine installation as the F4U performance increase significantly, although I could be wrong. I think the significant increases in hp post 1942 made smaller items in drag reduction such as elliptical wings and mid mounted wings, and possible radial engine installation of minor importance.



I don't think that Focke-Wolf had anything significant to teach US manufacturers in radial engine installation. Bluntly, I think the Fw190's radial installation was inferior to the US installations. I don't know why the RAF needed to see an Fw190 to become convinced that high performance and radial were not mutually exclusive features in a fighter aircraft; I'm sure that the British air attaché to the US had inklings that the Corsair had topped 400 mph on a test flight, the first US single-engined fighter to do so. 

A lot of effort went into the nacelle design for most multi-engined aircraft, especially after the DC-2 and DC-3 showed that aerodynamic improvements offered lower operating costs. Overall, I think that the contribution of non-military aircraft design and development to aerodynamics in the 1930s is underestimated.


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## GrauGeist (Sep 27, 2013)

swampyankee said:


> I don't think that Focke-Wolf had anything significant to teach US manufacturers in radial engine installation. Bluntly, I think the Fw190's radial installation was inferior to the US installations. I don't know why the RAF needed to see an Fw190 to become convinced that high performance and radial were not mutually exclusive features in a fighter aircraft; I'm sure that the British air attaché to the US had inklings that the Corsair had topped 400 mph on a test flight, the first US single-engined fighter to do so.
> 
> A lot of effort went into the nacelle design for most multi-engined aircraft, especially after the DC-2 and DC-3 showed that aerodynamic improvements offered lower operating costs. Overall, I think that the contribution of non-military aircraft design and development to aerodynamics in the 1930s is underestimated.


Kurt Tank took the established NACA design of the 1920's and improved on it. Not only did he enhance the cooling effect of the ducted spinner, but the design was seen to improve thrust due to the compressed hot air as it passed through the cowling.


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## davparlr (Sep 27, 2013)

Tank's first effort was a failure ala P-66. Did anyone else use a spinner fan in their radial? Certainly the late model F4U and F8F did not. In fact they did not even use a spinner cover. The beautiful Sea Fury used a spinner cover but not a ducted fan. As I have stated, I don't think the design was more efficient than the F4U design although we only have data on the total airframe and not just the engine installation.


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## futuredogfight (May 11, 2014)

I have read that the Hawk was up armed by the Finns with 2 12.7mm MG and 4 7.7mm MG by the mid Continuation War. Reports said that the addition of these weapons didn't affect the Sussu's handling and performance.


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## Garyt (May 14, 2014)

> Not the Zero. By 1942 Zero was a poor performer.
> No point copying that.



In most of 42 the standard US carrier fighter is still the Wildcat, which the Zero can handily out fly, though it is indeed rugged.


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## GregP (May 14, 2014)

The Zero a poor performer by 1942? Hardly. It was thought to be almost invincible until well into 1943, almost 1944 by the US Navy. Even then it was well respected when encountered if flown by an experienced pilot. It remained a threat if well flown until the war ended.


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