Which is the better fighter, P-40F or Typhoon?

[Greyman]

• I think your weight is really high here (original factory production? it's closer to max gross weight (i.e. with external fuel tank etc.) P-40F normal loaded weight (with 6 guns) is 8,500 -source and -source, P-40L normal loaded weight is 8,079 lb - source. The stripped P-40F as actually used in combat should be similar to that.
• Climb boost setting is undoubtedly low at 48" - takeoff power rating is supposed to be 54" (giving 1,300 hp) and they routinely took off at higher settings than that, pilots often mentioned climbing at WEP particularly during interceptions.
• Initial rate of climb is supposed to be 3,250 for the P-40F (with six guns), 3,300 ft / min for the P-40L- source

The sources from those links are all a) of the "Biff's Big Book of WWII Airplanes*" type and b) lacking in any information on aircraft condition, weight, and engine settings. Methods of correction are also potentially different. I'll stick with A&AEE measurements, which listed 8,910 lb as "typical service fighter load". It seems the A&AEE, as a rule, tested all aircraft fully loaded or at maximum take-off weight for the aircraft at the time of testing.

RE: engine settings in the climb -- in order to compare like-with-like I illustrated the maximum continuous climb settings, not 1-minute take-off settings.



*no relation/disrespect to any forum members - been using the phrase for about 20 years.

 

[Shortround6]

I would guess, repeat guess, that not very many P-40Fs flew at 20,000 ft or above when escorting B-26s. WHY????

Because the B-26 had engines with critical altitudes of 13,500 ft. and max continuous of 13,000 ft.
B-25 engines had critical height of 12,000ft.

My reason has nothing to do with the critical altitude of the engine in the P-40F

BTW you get best fuel economy using low blower as high as you can as long as it provides the power needed for the speed you are flying.

B-17 engines had critical altitudes 25-27,000ft although they rarely flew quite that high in large formations. Turbo rules are a bit different.

While you want at least some of the escort above the bombers you do want to keep them in sight. A lot depends on weather conditions.

We have manuals for many of these planes in the technical section of the website.

for the P-40F the manual says it took 12.8 minutes to get to 20,000ft with a gross weight of 8500lbs and an under fuselage load (52 gallon or 75 gallon tank or 500lb bomb.
It took 43 US gallons of fuel to start, warm up, taxi and climb to 20,000ft (it only took 34 gallons to get to 15,000ft)

At 9300lbs (and P-40F could go over 8500lb without a drop tank) it took 17.5 minutes to get to 20,000ft and the plane use 51 US gallons. This is using 3000rpm and 48.2 in for the first 5 minutes of climb and 2650rpm and 44.2 in for the time after 5 minutes.

This is for a single plane, not a formation.

And by the way, a P-40F at 9300lbs may need a bigger airfield than a Handley Page Halifax.
3950ft to clear 50 ft at sea level on a 32 degree F day.

for your consideration the fuel tanks on the P-40F were used this order.
1. front wing tank for starting and take-off
2. the belly tank.
3. The fuselage tank (behind pilot) until 35 US gallons are left.
4. the front wing tank .
5. The rear wing tank.
6. the fuselage tank 35 gallon reserve.

 

[pbehn]

The British had Gloster Gladiators on Malta in 1940, it shot some enemy aircraft down. That doesn't mean the Gladiator was the best plane in 1940s RAF it means it was the only one they had in Malta. The planes they shot down weren't the best in the Axis either they were just the ones they had there That is how I see most of these discussions about the P-40 in N Africa and Italy, sometimes things get used for stuff they were never really designed for but in many situations you use what you have because waiting isn't an option.

 

[Shortround6]

Game show announcer voice........

THE MANUAL SAYS

Empty weight...................................................................................... 6537lbs
Basic weight with 6 guns, gun sight and oxygen...................7027lbs
Guns weighed 471lbs for 6, adjust as you see fit.

Pilot 200lbs
gas weights
222lbs for forward wing tank
324lbs for rear wing tank
396lbs for fuselage tank
312lbs for the drop tank
54lbs for the drop tank installation.
423lbs for 1410 rounds of .50 cal ammo.

gross weight for max fuel .............................................................9116lbs
gross weight for design load*......................................................8505lbs
gross weight for max internal fuel.***.......................................8860lbs
Gross weight for ground attack**...............................................9347lbs

* no drop tank and forward wing tank empty
"" single 500lb bomb and full internal fuel
** and *** have 1686 rounds of .50 cal ammo
*** also has 27lbs of extra radio gear.

 

[Greyman]

In circa 1940, Chennault sent a full report on Japan's A6M to the Leaders of the USAAF and RAF, noting among other things, its 1,000 mile range. I can't speak for the RAF, but the USAAF simply tossed the report in a drawer when they saw Chennault's name.

An Air Ministry intel report dated 20 May 1940 says:

The following information in respect of a new type 0 (i.e. made in 1940) fighter with retractable u/c has been received. These figures will not be included in C.D. 131 until confirmation is obtained.

Type: T.O Mitsubishi S.S.F. (T.S.F.?) L.W.M. Deck. landing?
Engine: One 14 cylinder radial 800 - 900 H.P.
Ceiling: 23,000 to 34,000 ft.
Max. Speed: 345 to 380 m.p.h.?
Cruising Speed: 210 to 250 m.p.h.
Endurance*: 6 - 8 hours with extra tanks
Armament: 2 x 20 mm. cannons in the wings. 2 x 7.7 mm. M.G. positions unknown.

* Combat reports indicate that this aircraft has a range of 840 miles with an ample margin for combat.

 

[Navalwarrior]

An Air Ministry intel report dated 20 May 1940 says:

The following information in respect of a new type 0 (i.e. made in 1940) fighter with retractable u/c has been received. These figures will not be included in C.D. 131 until confirmation is obtained.

Type: T.O Mitsubishi S.S.F. (T.S.F.?) L.W.M. Deck. landing?
Engine: One 14 cylinder radial 800 - 900 H.P.
Ceiling: 23,000 to 34,000 ft.
Max. Speed: 345 to 380 m.p.h.?
Cruising Speed: 210 to 250 m.p.h.
Endurance*: 6 - 8 hours with extra tanks
Armament: 2 x 20 mm. cannons in the wings. 2 x 7.7 mm. M.G. positions unknown.

* Combat reports indicate that this aircraft has a range of 840 miles with an ample margin for combat.

Resp:
Thanks much for the confirmation on the report of 1940 received by the Air Ministry. Any such info needs/requires confirmation from a secondary source before it is accepted as accurate, but at least someone read the report!

 

[Schweik]

The sources from those links are all a) of the "Biff's Big Book of WWII Airplanes*" type and b) lacking in any information on aircraft condition, weight, and engine settings. Methods of correction are also potentially different. I'll stick with A&AEE measurements, which listed 8,910 lb as "typical service fighter load". It seems the A&AEE, as a rule, tested all aircraft fully loaded or at maximum take-off weight for the aircraft at the time of testing.

Well now that's just rude. I have much more authoritative books such as Americas 100,000, American Victory Roll, The Curtiss Hawks, all four volumes of Christopher Shores Mediterranean Air War, all the old Martin Caiden and Bill Gunston books, all the Black Cross Red Star books, autobiographies of 9 or 10 aces, about 40 Osprey books on aviation and so on and a couple of dozen others. I don't make up numbers out of my ass. I posted links to online sources for your convenience. As I pointed out already, it's very hard to find much about the P-40F, L or K online. I can quote sources from the books too.

Anyway, as Shortround noted in his posts, 8500 was in fact the design loaded weight. I think every other number I gave you checked out as well. I'll comment further on the weight issue in my reply to his post.

RE: engine settings in the climb -- in order to compare like-with-like I illustrated the maximum continuous climb settings, not 1-minute take-off settings.

As you yourself seemed to notice, the original WEP setting (which later became the military power setting) moved up from 48 to 54 to 60" Hg over time, and I have already posted pilot commentary (see here - direct pilot testimony from a wartime diary not from "Biff's Big Book of WWII Airplanes") where he mentioned a running fight going all the way from a Luftwaffe base back to his own base, with the P-40F going between 55- 65" Hg the whole time.

I didn't see any explanation as to why you used so much of a lower top speed than the English report I so helpfully linked for you? Did I miss that?

S

 

[Schweik]

Game show announcer voice........

THE MANUAL SAYS

gross weight for design load*......................................................8505lbs
gross weight for max internal fuel.***.......................................8860lbs
Gross weight for ground attack**...............................................9347lbs

* no drop tank and forward wing tank empty
"" single 500lb bomb and full internal fuel
** and *** have 1686 rounds of .50 cal ammo
*** also has 27lbs of extra radio gear.

I quoted 8500 as "loaded weight" I believe. That is again for the six gun fighter. Now we know that units which were doing a lot of air to air combat (some Fighter Groups more than others which I hope you remember me pointing out) tended to take 2 of their guns out of their P-40Fs along with the 480 rounds of ammunition that went with them* and other gear like the forward wing tanks, bomb shackles, radiator armor and one of the radios and some other stuff. Every US P-40 pilot I know of who commented on this mentioned that he had two guns taken out at some point. Robert Baseler apparently had 4 guns taken out for a while. Later on in Italy when Messerschmits were rare and they were flying more strafing missions some put the guns back in.

The P-40L, which had all these changes and maybe a couple more right out of the factory, and came with four guns, weighed in at just over 8,000 lbs loaded.

These weights are important because loaded with maximum fuel and especially with bombs or an external fuel tank, the P-40F/L was a bit overloaded. But this is not that unusual especially with later war fighter aircraft. What is the performance of a P-51D with maximum fuel and full external tanks? Is that the basis on which it's usually evaluated? Because I have read they didn't fly so well with that much petrol, especially in the rear fuselage tank.

The initial rate of climb for the P-40 seems to jump up from a dismal ~2,000 ft per minute with all the extra gas and six guns, to a far more sprightly ~3,300 ft per minute, possibly with a higher boost setting. I think that is one of the main reasons they took out those guns. I'm sure it helped with turn and roll but they already had an edge there.

Now when we are discussing these aircraft, do we want to consider how they were actually used? Or are we just trying to make a point?

S

* Sometimes more - P-40Ls only had 200 rounds per gun standard, sometimes less so they could have more rounds per gun as certain pilots apparently did

 

[Schweik]

The British had Gloster Gladiators on Malta in 1940, it shot some enemy aircraft down. That doesn't mean the Gladiator was the best plane in 1940s RAF it means it was the only one they had in Malta. The planes they shot down weren't the best in the Axis either they were just the ones they had there That is how I see most of these discussions about the P-40 in N Africa and Italy, sometimes things get used for stuff they were never really designed for but in many situations you use what you have because waiting isn't an option.

Aw that is really sweet.

The Gladiator had it's day, it was a good fighter. Shot down a lot of enemy planes. If you ever read Shores MAW Volume I there are some crazy battles between Gladiators and CR 42s in the Middle East.

But obviously they peaked quite early in the War. Faith Hope and Charity notwithstanding, Hurricane and even Spitfire units were having a very hard time in Malta for quite a while in 1942-43.

If you find records showing Gladiators shot down hundreds of Bf 109s, or even two or three standout incidents where they got 3 to 1 victory ratios against them, please definitely let me know I'll come running notebook in hand, that would definitely force me to re-evaluate the Gladiator and a whole lot of other things...

 

[wuzak]

The initial rate of climb for the P-40 seems to jump up from a dismal ~2,000 ft per minute with all the extra gas and six guns, to a far more sprightly ~3,300 ft per minute, possibly with a higher boost setting. I think that is one of the main reasons they took out those guns. I'm sure it helped with turn and roll but they already had an edge there.

Not exactly sure when this happened, but note that the Typhoon improved climb to ~3,800ft/min in early 1943 as the Sabre was allowed higher climb settings, which was similar to the Spitfire XII with the Griffon II. The Spitfire XII with the Griffon VI had a peak climb rate of ~5,000ft/min.

The Spitfire IX had a maximum climb rate of 3,860ft at introduction, using the Merlin 66.

The Spitfire IX with Merlin 66 (LF.IX) had a climb rate of 4,620ft/min at sea level and a peak of 4,700ft/min at 7,000ft. In FS gear the peak climb rate was 3,860ft/min @ 18,000ft. At 30,000ft a climb rate of over 2,000ft/min could be achieved.

"Sprightly" must be a relative term!

 

[Greyman]

I didn't see any explanation as to why you used so much of a lower top speed than the English report I so helpfully linked for you? Did I miss that?

Same reason as the other sources, no idea on the weight/condition of the aircraft. Plus I'm not too sure about how solid a (seemingly) quick test from the British Air Commission would be.

The A&AEE Kittyhawk II speed/climb I used is preferable because the testing appears to be exactly same as done on the Typhoon -- and with all the particulars listed. Weight, external equipment, engine settings, etc. Most books, even the great ones, don't have this kind of detail and are a very useful guide -- but again, when comparing 'like-with-like', you can't do better than looking into all the thorough work done at the A&AEE.

Anyone have a rough idea on how much speed would be gained from knocking 500 lb off of a 360mph fighter?

 

[Schweik]

I would point out Item 1 on the memo which states "Following performance figures for Kittyhawk II have been obtained by B.A.C. pilot and agree well with US Army results."

There are several books which give the top speed for the P-40F variously as 364, 368 or 370. For the P-40L it's usually 370 or 372.

Speed may not be affected very much by a ~400-500 lbs weight reduction; turn rate, ceiling and climb rate would be more impacted, roll rate too since they were removing wing guns.

Speed would be more impacted by things like removing bomb shackles or believe it or not, a radio antenna.

AVG and some other units did things like sanding, waxing, filling in or faring over holes etc. to get an extra 10 mph out of their fighters, but I have never read anything like that for the Western Desert (yet). It's possible they didn't have time. But the amount of actual records that are publically available are very few.

 

[Schweik]

Not exactly sure when this happened, but note that the Typhoon improved climb to ~3,800ft/min in early 1943 as the Sabre was allowed higher climb settings, which was similar to the Spitfire XII with the Griffon II. The Spitfire XII with the Griffon VI had a peak climb rate of ~5,000ft/min.

The Spitfire IX had a maximum climb rate of 3,860ft at introduction, using the Merlin 66.

The Spitfire IX with Merlin 66 (LF.IX) had a climb rate of 4,620ft/min at sea level and a peak of 4,700ft/min at 7,000ft. In FS gear the peak climb rate was 3,860ft/min @ 18,000ft. At 30,000ft a climb rate of over 2,000ft/min could be achieved.

"Sprightly" must be a relative term!

There's sprightly and then there's cheetah. But 3,300 fpm isn't terrible for mid 1943.

P-51D had a climb rate of 3,200 ft per minute
Fw 190A-8 had a climb rate of 2,953 ft per minute
Bf 109G-6 had a climb rate of 3,345 ft per minute and so on*

Anyway I never claimed the P-40F or L had a great rate of climb, it didn't, I was just pointing out it became much more competitive when used as it was used in combat in the Med - with a bit of weight cut out and slightly higher boost settings than the original factory limits (not talking about crazy overboost here either).

*I'm sure 109G maintained that rate of climb forever compared to a P-40L, I'm not claiming otherwise.

 

[Shortround6]

As you yourself seemed to notice, the original WEP setting (which later became the military power setting) moved up from 48 to 54 to 60" Hg over time

Please stop with this. The 48in was Military power from the start It is 9lb of boost. Unless you think the Merlin XX or Packard V-1650-1 had a military rating of 6lbs (42in) or something originally. Take off was allowed 54in (12 lbs) boost from the start. With an override on the throttle. WIth a two speed supercharger the engine would often tolerate more boost in low gear than in high gear because low gear heated the air less and so it was less prone to detonation. However there was only boost control mechanism so after the throttle was retarded after take-off the boost limit for both gears was 9lbs. Yes it was later changed to 60in when the US approved WEP power settings. Please note the British on some models of the XX series wound up with different allowable boosts for high and low gear but reversed 14lbs in low gear and 16lbs in high gear?
Also note that the US government did not allow combat or War emergency power settings until Dec of 1942, which is 11 months after production begin on the P-40F.
Please remember the main difference between military power and WEP power was that the use of Military power by the pilot did NOT require notifying the crew chief, logging the minutes used in the aircraft/engine record book, and did NOT require more frequent spark plug changes and/or maintenance procedures.

That is again for the six gun fighter. Now we know that units which were doing a lot of air to air combat (some Fighter Groups more than others which I hope you remember me pointing out) tended to take 2 of their guns out

That is why I gave the weight of 6 guns and said adjust weight accordingly.

Anyone have a rough idea on how much speed would be gained from knocking 500 lb off of a 360mph fighter?

3-5mph for the weight maybe less. As mentioned, it is the associated drag that is the speed killer. extra gun muzzles protruding through wing, extra cartridge case slots and so on.
easier to take out than add on. Many tests will state if the gun muzzles are taped/covered and some even state if the cartridge case slots are left uncovered. bullets will blow the muzzle covers off. Taped or covered ejection slots are a cheat as there is no great force to the ejected round to move/tear any such covering and after as very sort period time the cases that don't get out of the airplane will back up and jam the gun/s.

 

[Schweik]

I know... Greyman said (if I read him correctly) that 54" was a 1 minute power setting or something similar. I was pointing out that it was not.

Also keep in mind what the War Dept officially allowed and what was used in the field are two different things and one followed the other often. The war diary anecdote I quoted (with 65" Hg mentioned, no doubt at low altitude) was from Oct 42. So obviously he was able to get his throttle where he wanted it.

 

[Shortround6]

true but there is still a difference between the two different powers. The engine chart in the manual is dated Dec 18th 1942. (the manual is later as it specifies at which serial number P-40L the forward fuel tank was taken out) .
The Throttle had a crossover gate the lever had to moved through in order to get the 54in pressure on the ground, no time limit is given in the chart but the the manual for taking off says the "extreme throttle position should be used only until all obstacles are cleared." and then goes on. granted when manuals were updated they didn't always change all the language.
The engine chart also says at the bottom after the asterisk in the time slot for war emergency

*To be used in pre-combat or combat zones ONLY. EMERGENCY ONLY

underlining and capitols are in the original.
Military power just says 5 minute limit. there is no time limit given for the take-off power, everything else says "cont."

 

[Greyman]

Did some digging around ... first few tests at the A&AEE (August 1942) list the following limitations:

Take-off (3 min. or 1,000 feet) 54 inches, 3000 rpm
Max. climb (30 min. limit) 48 inches, 2850 rpm
Max. emergency climb above 20,000 ft. (short periods only) 48 inches, 3000 rpm
Max. cruising (rich) 44 inches, 2650 rpm
Max. cruising (weak) 38 inches, 2650 rpm
All-out level/combat (5 min. limit) 48 inches, 3000 rpm

But, I see a later paper (still August 1942 testing), detailing engine cooling trials adds this line to the limitations:

Note A max. of 54 in.Hg. boost pressure is permitted in M. gear only, for short periods during an emergency. This is obtained by operating the boost control cut out.

It also ups the 30 minute limit on the max climb setting to 60 minutes.

**EDIT: I should say the report itself is from 18 Oct 1942, which may account for the difference in engine limitations, even though the flight testing itself was done earlier that August.

 

[eagledad]

Gentlemen:

Basic weight of P-40F is listed as 7027 pounds. That is with 6 machine guns and no ammunition for the guns. The weight of a 50 cal gun is listed as 47 pounds, so the basic weight of the P-40 L would be 7027-94 pounds or 6933. For the P-40F, useful load includes 200 pounds for pilot and parachute, 720 pounds for fuel (119 US gallons), 135 pounds for oil (17.5 US gallons) and 423 pounds of ammunition. This gives a gross weight of 8500 pounds. For the P-40L, I reduced the ammunition weight by one third to 282 pounds. The gross weight of a P-40L would then be 8270 pounds.
Data Source P-40F and P-40L Pilot Flight Operating Instructions, revised June 20th 1943.

Please note that to reach 8500 pounds, the P-40F/L has the front wing tanks empty.

Also, for the speed of a P-40F, please see

http://www.wwiiaircraftperformance.org/P-40/P-40F-Specifications_Performance.jpg

and

P-40 Performance Thread

Neither of the above sources give a max speed of 370 (though the speeds listed are roughly between 2 and 3 percent of 370), nor do they list any climb rates approaching 3000 feet/minute. However, they do give "average performance" of the P-40 in the field. The second source is from Tactical Planning Characteristics and Performance

FWIW

Eagledad.

 

[Schweik]

P 40L has more than just the two guns and ammunition removed. They took out the forward wing tanks, radiator armor and some other stuff. I've already pointed this out a few times.

I've seen that stat block many times but it looks like something made for public release. it's alll low ball figures.

 

[Shortround6]

P 40L has more than just the two guns and ammunition removed. They took out the forward wing tanks, radiator armor and some other stuff. I've already pointed this out a few times.

I've seen that stat block many times but it looks like something made for public release. it's alll low ball figures.

From the Manual.
"On P-40L-5 airplanes serial number 41-10480 and up, the front wing tank installation has been eliminated. "

That is tank, singular, not plural. This saved about 100-105lbs? AHT says 103.

Units in the field could accomplish this but it took a bit of work as you needed to change some of the fuel lines and install a second fuel pick up in the rear tank to do a proper job.

the armor was included in the armament provisions weight catagory (which might well include gun mounts/brackets, ammunition boxes, feed chutes, gun controls in the cockpit and so on.) which varied form a high of 328lbs to a low of 297lb on an N (six gun), the next lowest was 313lbs on a K.
The armor was a 3/8in plate (15lbs per sq ft) located forward of the instrument panel and the 5/16s (12.5lbs per sq ft) plate/s located behind the pilot.
The manual says nothing about any changes between the F and L, while it does detail the changes in unlocked landing gear warning device (horn to light, change in flap position indicators, change from electric to manual cowl flaps and several other items of "stuff". the forward armor (specified as non magnetic) goes from side to side and from about the center of the propeller to the top of the cowl It is very roughly 1/4 the size of the rear armor. No mention is made of any armor protecting any part of the cooling system.


I would note that the overload figures are certainly subject to change in the field as not only was 52 gallon drop tank replaced by a 75 gallon tank but the F (and L?) had a little known feature whereby they could carry a 100lb under each wing (or 3 smaller bombs). Units in the field may have adapted such a mounting point to heaver bombs before the factory and government officials increased the bomb load on later planes. Or local units brought older aircraft more into line with the newer ones? You had a mounting point, you had a release mechanism in place/control in the cockpit. adapting the brackets/rack to take bigger bomb would have been how hard? And if you yanked a pair of guns and restricted the ammo load of the remaining guns you might not be overloading the plane that badly. Max ammo load for six guns was 506lbs so there was certainly some wiggle room.