How good a plane was the P-40, really?

Think Tanker said:

Attached are the range specifications for a typical P-47C, ranging from the C-1 to C-15 sub-blocks. On internal fuel, the aircraft is loaded with 305 US Gallons at a take-off weight of approximately 13,500-lbs. This provides the following:
P-47C: 305 US Gallons internal, 13,500-lbs take-off weight, 650-miles range at Maximum Cruise power, or 400-miles at Maximum Continuous power (325-miles at low altitude).

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Thank you for the tables.
As a side note, the P-47D razorbacks were also with just 305 US gals of fuel in the internal tanks. The P-47D bubbletops received the bigger (taller) main tank, with 270 gals now, for the total of 370 gals per aircraft.

Think Tanker said:

While I understand the push-back on that terminology, I believe a it's fair phrase to apply, though undoubtedly the language is slightly hyperbolic in the case of the Spitfire. Attached are the range specifications for a typical P-47C, ranging from the C-1 to C-15 sub-blocks. On internal fuel, the aircraft is loaded with 305 US Gallons at a take-off weight of approximately 13,500-lbs. This provides the following:
P-47C: 305 US Gallons internal, 13,500-lbs take-off weight, 650-miles range at Maximum Cruise power, or 400-miles at Maximum Continuous power (325-miles at low altitude).
View attachment 806484

If we compare to the contemporary P-40 series (excluding the P-40L and P-40N-1, since both are assuredly inferior in range due to their ~20% reduction in internal fuel capacity). we have the following information:

P-40F: 157 US Gallons internal, 8,850-lbs take-off weight, 600-mile range at Maximum Cruise power, 425-miles at Maximum Continuous power (375-miles at low-altitude).
P-40K: 157 US Gallons internal, 8,800-lbs take-off weight, 600-miles range at Maximum Cruise power, 350-miles at low-altitude Maximum Continuous (no data-point for high-altitude)
P-40M: 157 US Gallons internal, 8,800-lbs take-off weight, 550-miles range at Maximum Cruise power, 475-miles at Maximum Continuous power (325-miles at low-altitude).
View attachment 806486

Yes, there is subject to fine interpretation with each of these individual values, but I believe it does relay my position of "about on-par" adequately. While reasonable minds can disagree on where the line is for "about on-par", or what meets that metric, in my perception of the ranges of both aircraft are within a fairly narrow margin of difference--before later P-47 models are introduced, and become prolific in their carriage of large underwing tanks.

Information comes from the tactical planning charts for each aircraft type, unfortunately no data was present for the later P-40N models, otherwise I would've included them as well.

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I have seen this discussion many times before. It is based on the ultimate calling and ue of a single engined allied fighter was to escort bombers into Germany. No escort fighter was ever ordered or designed in the period. The P-47 performed its first missions in Europe in March April 1943. That is three years after the battle of France and Britain. The P-47 was designed as an interceptor but was never charged with intercepting anything in England because that duty was left to a plane that was better at the role, the Spitfire. The first USAAF bombing missions were in 1942 and escorted by the Spitfire because it was there and the others werent. The British had the Spitfire and were developing a longer range fighter in conjunction with a company called North American Aviation, it was found that when a Merlin engine was fitted in this plane called a Mustang that it was exceptional in the role of "escort fighter". The Hurricane was undoubtedly inferior to all other marques, that came later and werent there. Its role was frequently taken over by the Spitfire which served also in roles it wasnt designed for until the later planes that werent there became there. The whole point of the strategic bombing offensive was to weaken Germany and especially its Luftwaffe prior to D-Day but the P-47 couldnt reach deep into Germany until around D-Day, which was also around the start of the jet age.

tomo pauk said:

180-190 mph is about 300 km/h, and we know that going slow is greatly benefiting the range. See here for Bf 110C doing 1040 km at ~520 km/h with full internal tankage.

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Thanks for that, interesting how an aside gains a life of its own, but alongside the C-2 doing 1,040 km is the C-1 doing 780 km, with a lower fuel load, yet there were few changes between the two. Also the speed quoted is almost the reported top speed of the type, which should give an economic cruise well beyond the 1,500 km mark on internal fuel. My German is not good enough to deal with the font and abbreviations to clarify things.

The RAF calculated fighter ranges by deducting the fuel needed to run the engine at full power for 15 minutes, the rest being available for cruise, result being Spitfire official economic cruise ranges at 15,000 feet were I 575 miles, II 530 miles, V 480 miles, IX 434 miles.

Think Tanker said:

P-47C: 305 US Gallons internal, 13,500-lbs take-off weight, 650-miles range at Maximum Cruise power, or 400-miles at Maximum Continuous power (325-milesat low altitude)
If we compare to the contemporary P-40 series (excluding the P-40L and P-40N-1, since both are assuredly inferior in range due to their ~20% reduction in internal fuel capacity). we have the following information-40F: 157 US Gallons internal, 8,850-lbs take-off weight, 600-mile range at Maximum Cruise power, 425-miles at Maximum Continuous power (375-miles at low-altitude).
P-40K: 157 US Gallons internal, 8,800-lbs take-off weight, 600-miles range at Maximum Cruise power, 350-miles at low-altitude Maximum Continuous (no data-point for high-altitude)
P-40M: 157 US Gallons internal, 8,800-lbs take-off weight, 550-miles range at Maximum Cruise power, 475-miles at Maximum Continuous power (325-miles at low-altitude).

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Thanks for the range charts, firstly it is interesting how the economic cruise ranges of the various P-40 were compared to the Spitfire I. Staying with economic cruise how Francis Dean picked up on the gap between the P-47 and P-40 range, if the aircraft were in the Pacific this is the key range. Moving to the European Theatre the maximum cruise power would be more appropriate, with the P-47 having a 50 to 100 mile advantage, then comes maximum continuous power, the P-47 being equal worst.

It says something about the engines that the P-47 has a big range advantage at economic cruise, still an advantage at maximum cruise but is equal worst at maximum continuous power. While the Merlin was as good as the Allison but faster at economic cruise, gap closing at maximum cruise, and slightly better at maximum continuous at about the same speed.

Finally dividing the range by endurance throws up some interesting results, P-40M 10,000 feet economic cruise 700 miles at 195 mph, 25,000 feet maximum cruise 550 miles at 205 mph. I suspect a few of the numbers.

For "contemporary" the major theatre where the P-40 and Spitfire served together was in the Mediterranean, as of end December 1943 the RAF in theatre had 25 Spitfire mark I, 1,718 V, 6 VI, 398 VIII, 764 IX, 43 PR.IV, 51 PR.XI along with 153 Kittyhawk I, 155 IA, 165 IIA, 217 III and 135 IV, end June 1944 it was 18 Spitfire mark I, 1,347 V, 5 VI, 262 VIII, 879 IX, 32 PR.IV, 76 PR.XI along with 56 Kittyhawk I, 91 IA, 123 IIA, 158 III and 360 IV. The 456 Kittyhawk IV allocated to the RAF were 56 N-1, 150 N-5, 50 N-15 and 200 N-20. So as of 1943 the majority of Kittyhawk IV were short ranged, by the looks of things the 100 P-40L/mark II had been removed from inventory. It is really easy to choose say Spitfire VIII versus P-40N-1, Spitfire longer range, or Spitfire IX versus P-40M, P-40 longer range.

In numbers terms the P-40L and N-1 were about 8% of production, while the Spitfire IX was around 29% but from the second half of 1944 more internal tankage was fitted, deducting these leaves say 15% of Spitfire production, throw in Seafires and it becomes 13%. If we are to ignore the shorter range P-40 versions we can ignore the shorter range Spitfire versions for comparison purposes. Types like the P-40 and Spitfire came in a large number of versions with different capabilities, selecting which versions to compare therefore tends to say more about the author than the aircraft. Similar for what conditions.

Think Tanker said:

Yes, there is subject to fine interpretation with each of these individual values, but I believe it does relay my position of "about on-par" adequately. While reasonable minds can disagree on where the line is for "about on-par", or what meets that metric, in my perception of the ranges of both aircraft are within a fairly narrow margin of difference--

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To conclude "about on par" requires operations run at maximum continuous power as that is where the P-40 and P-47 ranges converge or the P-40 is superior, going to maximum cruise the P-47 range is 50 to 100 miles longer, economic cruise over 100 miles more, which means at economic cruise the Spitfire I range is "about on par" to the P-40 at 125 miles shorter. How many fighter missions were run at maximum continuous power versus at maximum and economic cruise?

Think Tanker said:

before later P-47 models are introduced, and become prolific in their carriage of large underwing tanks.

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More the extra 25% or so internal fuel.

Still interested in the MTO fighter bomber operations using 1,000 pound bombs, the P-38 units regularly used them.

Geoffrey Sinclair said:

Thanks for the range charts, firstly it is interesting how the economic cruise ranges of the various P-40 were compared to the Spitfire I. Staying with economic cruise how Francis Dean picked up on the gap between the P-47 and P-40 range, if the aircraft were in the Pacific this is the key range. Moving to the European Theatre the maximum cruise power would be more appropriate, with the P-47 having a 50 to 100 mile advantage, then comes maximum continuous power, the P-47 being equal worst.

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I don't believe any one of the values can be used in isolation, especially considering the different operational theatres the types were used. Worth noting that since the P-40 was defacto non-existent in the ETO, it's less of a metric which can be used. MTO (where the P-47 was less frequent, though the Spitfire was very prolific), PTO (both P-40 and Spitfire were somewhat prolific with the RAAF and others) and CBI (P-40 was very prolific, Spitfire not so much). Ideally an interpolation of the data-points would be used, and vary depending on the different operational theatres, intended roles, and anticipated flight-time endurance / fuel consumption.

Engine operational settings would doubtless vary quite significantly from a P-47 flying escort duties over the ETO versus a P-40 flying strike duties in the PTO. I don't believe it's a comparison that is conducive to a 'one-metric-fits-all' sort of comparison, in regards to whether higher power or economy settings are used. Certainly a topic worth discussing, though, if you have materials on the Spitfires for such data, though! I'm sure it exists somewhere, but 'ball-parking' the estimates is the best I can provide between the P-47 and P-40 comparisons. Especially if we're to consider the different theatres both types were principally used in.

Geoffrey Sinclair said:

Finally dividing the range by endurance throws up some interesting results, P-40M 10,000 feet economic cruise 700 miles at 195 mph, 25,000 feet maximum cruise 550 miles at 205 mph. I suspect a few of the numbers.

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Agreed. As mentioned, I also suspect a few of the numbers to carry some margin of error, though as a bird's eye perspective I believe it is suitable enough.

Geoffrey Sinclair said:

For "contemporary" the major theatre where the P-40 and Spitfire served together was in the Mediterranean, as of end December 1943 the RAF in theatre had 25 Spitfire mark I, 1,718 V, 6 VI, 398 VIII, 764 IX, 43 PR.IV, 51 PR.XI along with 153 Kittyhawk I, 155 IA, 165 IIA, 217 III and 135 IV, end June 1944 it was 18 Spitfire mark I, 1,347 V, 5 VI, 262 VIII, 879 IX, 32 PR.IV, 76 PR.XI along with 56 Kittyhawk I, 91 IA, 123 IIA, 158 III and 360 IV. The 456 Kittyhawk IV allocated to the RAF were 56 N-1, 150 N-5, 50 N-15 and 200 N-20. So as of 1943 the majority of Kittyhawk IV were short ranged, by the looks of things the 100 P-40L/mark II had been removed from inventory. It is really easy to choose say Spitfire VIII versus P-40N-1, Spitfire longer range, or Spitfire IX versus P-40M, P-40 longer range.

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P-40L is the Kittyhawk II (IIA in common reference) and P-40N-1 are early model Kittyhawk IVs. The vast majority of all Kittyhawk IVs were not P-40N-1 models with the reduced fuel capacity, but rather the P-40N-5 onwards with enlarged fuel capacity analagous to the P-40M types. For sake of this discussion I am also willing disregard that the designation distinction between the P-40F and P-40L were often used interchangeablely, but to the benefit of your comparison let's assume 100% of all Kittyhawk IIAs in those numbers are P-40Ls. Neither majority in the 1943 figure provided or the 1944 figure are of the short-ranged 'stripped' P-40L or P-40Ns, far as I can verify. The P-40N-5 onwards had 161 US Gallons of internal fuel capacity compared to the 122 US Gallon capacity of the P-40N-1.

Meanwhile the Spitfire Mk. VII likewise made up a small proportion of the total aircraft in-theatre. The most common types were the shorter-ranged Mk. Vs and IXs, which I was using as the basis for my comparison. If you wish to say a Spitfire Mk. VIII is longer-ranged than a P-40N-1, I have no qualms with that statement. But by-and-large the P-40 series as a whole had longer legs than the Spitfires, as evident from the preponderance of Mk. V/IX in the latter and P-40E/F/K/M/N+ in the former. On the whole I believe my assertions of range are reasonable, though I've no issue if we have a respectful disagreement on that front.

Geoffrey Sinclair said:

In numbers terms the P-40L and N-1 were about 8% of production, while the Spitfire IX was around 29% but from the second half of 1944 more internal tankage was fitted, deducting these leaves say 15% of Spitfire production, throw in Seafires and it becomes 13%. If we are to ignore the shorter range P-40 versions we can ignore the shorter range Spitfire versions for comparison purposes. Types like the P-40 and Spitfire came in a large number of versions with different capabilities, selecting which versions to compare therefore tends to say more about the author than the aircraft. Similar for what conditions.

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I don't believe we necessarily need to split hairs on such a matter, I think it's suitably reasonable if we 'block' compare the most prolific production types of each aircraft and leave it as such. There's no perfect apples-to-apples comparison, though as a matter of casual discussion I believe the bar of 'most common types' is acceptable for these purposes.

Geoffrey Sinclair said:

To conclude "about on par" requires operations run at maximum continuous power as that is where the P-40 and P-47 ranges converge or the P-40 is superior, going to maximum cruise the P-47 range is 50 to 100 miles longer, economic cruise over 100 miles more, which means at economic cruise the Spitfire I range is "about on par" to the P-40 at 125 miles shorter. How many fighter missions were run at maximum continuous power versus at maximum and economic cruise?

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Assuming we have adequate data, I'd love to compile such information into a spreadsheet of relative consumption, endurance, relative powers and 'average' power through sorties. Though that's probably an ambition for another day, unfortunately...

Geoffrey Sinclair said:

More the extra 25% or so internal fuel.

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Yes, though that was standard only on the 'later' (in the context of this conversation at least) P-47D-25-RE onwards, as I understand. As an aside, If someone is aware of information pointing to such internal fuel capacity being available on or before the P-47D-22-RE and P-47D-23-RA, I'd love to hear about it.

Geoffrey Sinclair said:

Still interested in the MTO fighter bomber operations using 1,000 pound bombs, the P-38 units regularly used them.

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I've never been able to find concrete sortie information and expenditure for all types in the MTO, sadly. My references for the P-40 in-theatre mostly extend to the combined use of 1,000-lb and 500-lb munitions on the P-40Ns, but the specifics of sortie payloads wasn't something I scanned when coming across their operational information years ago. If I'm back in town and can access those documents again, I'll see what I can find.

Single-use of the 1,000-lb munitions, as I recall, was more frequent in the PTO and CBI on older P-40E and P-40K type airframes. By the time of the P-40N underwing stores were more common. Though, if you happen across any expenditure or sortie information from the MTO, be sure to let me know. I need to dust off some of my old scans and files, it's been far too long since I've added to them, undoubtedly.

Some comments, the quoted 165 'Kittyhawk IIas' must include both the P-40F (II) and P-40L (IIa) airframes the RAF received because there was only 100 P-40Ls received by the RAF in the Mediterranean theatre.

The designation distinction between the P-40F and P-40L were NOT used interchangeablely by the RAF, that is the realm of later authors. And P-40F (II) and P-40L (IIa) are the correct RAF designations.

The bomb loads carried by the P-40N variants in Italy are quoted in the ORBs for 3 and 450 Sqns for each operation. 1000 lb bombs were carried on the belly shackles with 500 lb ones on the wings (the wings were not strengthened to take a 1000 lb load.

The Kittyhawk Mk.IIa airframes could carry 1000 lb under the belly but no wing load (horsepower limitations), The FT serialled Kittyhawk IVs were apparently limited to 3 x 500 lb loads and the FX serialled Kittyhawk IVs the full 2000 lb load (1000lb on the belly shackles and 500 lb under each wing).

However note that occasionally on long missions they would carry a drop tank under the belly and 500 lb each wing. The blocks received by the RAF had no provision for carrying a drop tank under the wing (not having the plumbing in place for it), I believe some later blocks did have such (there are a few images of USAAF P-40s fitted with them).

The images show a) closeup of 1000 lb under a Kittyhawk IIa
b) Ken Richard's Kittyhawk IIa CV-K FS433 with a 1000 lb load
c) A 450 airframe with the full 2000 lb load.
d) Belly tank plus 2 x 500 lb load.

There were all sorts of other combinations possible. At one stage 450 tried a load of 6 x 250 lb (2 under the belly and 2 each wing) but gave that idea away as they did not find them stable enough in flight.

Steve Mackenzie

Hornet133 said:

d) Belly tank plus 2 x 500 lb load.

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Thank you very much for the contribution
Do you know perhaps what kind/size the drop tank on that picture was?

Standard P-40 tank, whatever size they are.

Most likely the 75-Gallon type by that point in the War, though it could also be a 52-Gallon type, though it seems to lack the more 'slender' shape of one.

As an aside for the 170-Gallon discussions, I've found indications of their testing on P-40Ns armed with two 500-lb bombs, but cannot find photos of the type with this tank installed for the life of me. It's much more 'pancake' like than the smaller 52-Gal and 75-Gal types, so if anyone happens to have images of it I'd greatly appreciate it.

And in the spirit of some sharing photos, here are a couple more images with ordnance attached...

P-40F with 170 USgal DT

ThomasP said:

P-40F with 170 USgal DT

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If that tanks does not scream 'attach me under a P-40'....

tomo pauk said:

If that tanks does not scream 'attach me under a P-40'....

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Keeps it from scraping on the runway.

One the N's with plumbed wings they could carry one under each wing.
There was also an option for two 225 gallon tanks.
Very fuzzy photo in the manual.
Take off distance (ground run) was 4500ft.
Two 170 gallon tanks required 3800ft.
One 170 gallon tank required 2500ft

Actual take-off weight not given.

Shortround6 said:

Keeps it from scraping on the runway.

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Idea was that It would've boosted the usadility of the early P-47s by a huge margin

Shortround6 said:

One the N's with plumbed wings they could carry one under each wing.
There was also an option for two 225 gallon tanks.
Very fuzzy photo in the manual.

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A much better photo is in the AHT book, pg. 253.

tomo pauk said:

Idea was that It would've boosted the usadility of the early P-47s by a huge margin

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Maybe, I don't know if the 170 gallon tank would work at high altitude.
Manual for the P-40N suggests cruising at 10,000ft. Of course trying to cruise a P-40 at around 20,000ft is problem anyway. Both due to the engine and the lack of oxygen for a long distance flight. I don't know if it wouldn't work.
Number of available tanks may be a problem.

tomo pauk said:

A much better photo is in the AHT book, pg. 253.

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Different photo (?).
Plane in AHT is supposed to be a P-40E (caption problem?) with very wide tanks. Testing was often done months (or over a year) before production or use in service (included in manual).
Photo in the Manual, while very fuzzy, appears to have round tanks. Perspective seems to have the tanks pointed outwards but the flattened appearance is not there. Camera definitely shows the sway braces angled outwards.

Shortround6 said:

Maybe, I don't know if the 170 gallon tank would work at high altitude.

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The 165 gal tanks worked at high altitude. Expecting that the 170 gal tank will not is negativity galore.

Shortround6 said:

Number of available tanks may be a problem.

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A little bird old me that there was a country, back in the 1940s, that possessed 40-50% or the world's 'war-making' industrial capability. For example, in that country, the 165 gal tanks were manufactured in thousands.
But, going up by just 5 gals more, and that country can't make them in quantities?

tomo pauk said:

The 165 gal tanks worked at high altitude. Expecting that the 170 gal tank will not is negativity galore.


A little bird old me that there was a country, back in the 1940s, that possessed 40-50% or the world's 'war-making' industrial capability. For example, in that country, the 165 gal tanks were manufactured in thousands.
But, going up by just 5 gals more, and that country can't make them in quantities?

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Difference is ferry tanks vs combat tanks.
The 170gal tanks were not expected to be used in combat, at least not as originally designed?
And for Ferry use perhaps while they were reusable (unlike the early P-47 belly tanks) I don't know enough about long range ferry operations with P-40s to know when they were used.
Also when. Even 170 ferry tanks would have been a big benefit to the North Africa ferry routes

P-40s could have flown 1600-1700 miles per hop (depending on weather/light) instead of the approximately 1000-1200 miles using a 75 gallon belly tank.
This also assumes they can get out of an intermediate/middle of journey landing field with a full 170g belly tank.
Or in the Pacific flying out of Australia.
They may not have shown up until early/mid 1943.

The US could have produced a lot of things, the fact that they even bothered to design and build special drop tanks for the P-40 is evidence of that.
But they also tried to build things they needed and it was one thing to make assorted tanks, it is a bit different sending all kinds of different tanks all over the globe incase certain air craft happen to show up and it might be handy if they are on hand when the Plane X shows up.
US built a 175 gallon tanks for P-39s.

Too fat to fit under a P-47?
P-40 170g tank gave the wrong CG? (nose wheel made it ride too far back?)
170g P-40 tank was too wide to fit between the landing gear doors?
Ferry tanks were sometimes 'recycled'. Sent back in C-47s or other cargo plane on return flights to be used again.
The ferry tanks also had more restrictions than combat tanks as regards allowable speeds and flight maneuvers.

Shortround6 said:

Difference is ferry tanks vs combat tanks.
The 170gal tanks were not expected to be used in combat, at least not as originally designed?

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Hopefully the tanks should be dropped before the combat. By 1942, even the folks that were staunch opposition for the drop tanks in the USAAF knew better.

Shortround6 said:

The US could have produced a lot of things, the fact that they even bothered to design and build special drop tanks for the P-40 is evidence of that.
But they also tried to build things they needed and it was one thing to make assorted tanks, it is a bit different sending all kinds of different tanks all over the globe incase certain air craft happen to show up and it might be handy if they are on hand when the Plane X shows up.

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I'm not sure that I've ever advocated the aircraft-specific drop tanks.

P-38 165g tanks may have started out combat capable. Of course they were sticking them on the Turbo P-38 so they might have anticipated high altitude flight?
I believe the earliest P-38 tanks were 75 gallon?
P-38s got 150g tanks and later 165g tanks?
Later 300g and then 330g tanks or different names for the same tank?

Using Ferry tanks might be a good idea and it may be bad idea.
A lot depends on conditions.
P-47s (and P-38s?) required the fuel tanks to be pressurized over somewhere in the mid teens for altitude. The engine fuel pump would not suck the fuel out of the tanks at air pressure.
So the tanks needed a pressure fitting and an airline.
Shops might be able to modify tanks (depends on skill of mechanics and tools available).

tomo pauk said:

I'm not sure that I've ever advocated the aircraft-specific drop tanks.

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You have not have advocated it but it seems like even the US had 3-4 different drop tanks just in the 150-175 gallon range. That is just the US Army, Navy tanks may have been different?
I have no good reason why they had so many.
Guessing that one or more did not work on certain planes.
Which would mean that those specialized tanks would tend to be in areas where those planes were and not swapped around. Might also mean that the ferry tanks tended to stay in the Ferry route bases and not be used to move planes from ferry depot to front line fields (use delivery flight to deliver 1st combat tank rather than use a C-47 to fly in a bunch of empty tanks).

Shortround6 said:

Difference is ferry tanks vs combat tanks.
The 170gal tanks were not expected to be used in combat, at least not as originally designed?
And for Ferry use perhaps while they were reusable (unlike the early P-47 belly tanks) I don't know enough about long range ferry operations with P-40s to know when they were used.
Also when. Even 170 ferry tanks would have been a big benefit to the North Africa ferry routes...

P-40s could have flown 1600-1700 miles per hop (depending on weather/light) instead of the approximately 1000-1200 miles using a 75 gallon belly tank.
This also assumes they can get out of an intermediate/middle of journey landing field with a full 170g belly tank.
Or in the Pacific flying out of Australia.
They may not have shown up until early/mid 1943...

...P-40 170g tank gave the wrong CG? (nose wheel made it ride too far back?)
170g P-40 tank was too wide to fit between the landing gear doors?

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A couple comments on this,

I. It appears that, whether originally designed to be used in combat or not (something I've been unable to verify), the tanks were tested in combat-loaded conditions. Also, separately, the 170-Gal tanks appear to weigh ~1,000-lbs, and were provided installation bulletins for the older 'legacy' Warhawks. Ir doesn't appear from what I've gathered that these were intended exclusively as 'ferry' tanks, but I cannot confirm nor deny whether they were used in combat.

II. It appears that the 170-Gal tank did not reduce the margin of stability to the point where it made the aircraft naturally unstable, nor did the wing and fuselage mounts interfere with the landing gear. This is one advantage as a consequence of the "twist, back and up" style of landing gear.

Provided are some images from the Curtiss P-40 engineering bulletins, as well as an P-40N-5 suitability report sourced from WWIIAircraftperformance.org.


Curtiss P-40 Engineering Bulletin for Installation of the 170-Gallon Tanks on Wing Stations.

Installation Location


Wing Tank "Plumbing" as Retrofitted


Fuel System Diagram for Retrofitted Aircraft

Test Conditions, with and without payload.

Performance Table for P-40N-5 with x1 170-Gal tank and x2 500-lb Bombs

Range Survey (Air Miles per US Gallon) for P-40N-5 with x1 170-Gal tank and x2 500-lb Bombs

As a point of interest, using the fuel values in this report, combined with the average fuel consumption during the Range Survey (for a datapoint, selecting the 'least efficient' datapoint on Auto Lean) we determine an approximate consumption of 1 US-Gal for every 3.3 miles, at an approximate TAS of 225mph. With the provided fuel of this aircraft, this would provide an approximate range of 1,080 miles at an average speed of 225mph TAS with the 170-Gal & x2 500-lb Bombs carried during the entire flight.

I am not drawing any conclusions from those values, just found it an interesting point to calculate. You may feel free to use the other datapoints or other interpretations to derive your own figures as required.

Hopefully you folks find this interesting, let me know if there's any additional information I can provide from these items. Otherwise, you should be able to find them through online archives fairly readily.

I was looking at P-40 operations in North Africa last night attempting to look at actual missions and distances. The Palm Sunday massacre easily came up. The P-40s of the 57th were flying from El Djem, Tunisia for a mission to Cape Bon. A distance of about 175 miles. The spotted the Ju-52s assembly low over the Med, and the air battle started. The 57th Fighter Group's webpage at Nellis had the story. Regardless of actual range on paper, it seems like missions were around 200 miles for the P-40 in practice. Does anyone have a copy of The Fabulous Fifty-Seventh Fighter Group of World War II, edited by Wayne S. Dodds?

Hornet133 said:

Some comments, the quoted 165 'Kittyhawk IIas' must include both the P-40F (II) and P-40L (IIa) airframes the RAF received because there was only 100 P-40Ls received by the RAF in the Mediterranean theatre. The designation distinction between the P-40F and P-40L were NOT used interchangeablely by the RAF, that is the realm of later authors. And P-40F (II) and P-40L (IIa) are the correct RAF designations.

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Correct, the RAF census pages I used lump all the F and L together as mark IIA and I missed that, also the increase in P-47 internal fuel capacity was 20%, not 25% as I quoted, problems I create by writing to a deadline.

The RAF Serial Registers call the P-40F received serials FL219 to FL368 mark IIA, they call the P-40L received serials FS400 to FS499 mark II usually, with the occasional mark IIA. The February 1943 census reports 2 Kittyhawk II in Britain, 105 IIA in the Middle East, end June 1944 deliveries were 2 mark II and 251 mark IIA, fun huh? All up 150 P-40F (no block number), 44 P-40L-10 and 56 P-40L-15 allocated to the RAF from US production, with 21 P-40F lost at sea, 2 to Britain, rest to Middle East. The P-40F and L used the 1,300 HP V-1650-1, the P-40F were delivered in the US April to July 1942, the P-40L January to March 1943.

Mark IV FT849 to FT904 were 56 P-40N-1 and FT905 to FT954 were 50 N-5, with 7 N-1 and 8 N-5 lost at sea, 15 N-1 and 6 N-5 to South Africa. The USAAF says wing bombs/fuel tanks came with the P-40N-5. The RAF serials FX498 to FX847 were N-5 (FX498 to FX597), N-15 (FX598 to FX647) and N-20 (FX648 on)

As far as I am aware the single engine fighter bomber use of the 1,000 pound bomb in Europe is heavily associated with the move to attacks on bridges and in Italy that shift occurred late enough that little data was available for the Overlord planners to decide what to do. Be nice to pin that down.

Think Tanker said:

I don't believe any one of the values can be used in isolation,

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Unfortunately that is what happened with the "about on par" comment. In the ETO the heavy bombers and their associated escorts tried for fast cruising at high altitude, the USAAF mediums apparently normally used economic cruise and definitely stayed at medium altitude.

I was doing most of the Spitfire to P-40 comparison, using the "about on par" value, to try and point out the problems of that designation, including selecting which version is to be used and why. I still do not think it has got through. My comments on the engine are about the way fuel consumption rose faster with speed in the P-47 than the P-40

It took a redesign of the front fuselage to add the extra 65 gallons of internal fuel into the P-47D-25-RE and D-26RA, there was no retrofitting. It then took quite a while to convert the existing combat units. Wing tanks had arrived with the D-15 and earlier versions could be retro fitted.

A key point in carrying external loads is the threat level, as long as the aircraft does not have to suddenly change course the load can sit there, pull G and watch it start to tear the aircraft to pieces.

12th Air Force. Double entries are for when a group is converting to another type.


57th FG non operational 1 to 8 January 1944. 33rd FG ceased operations after 2 February 1944, 27th and 86th FBG used P-40 mid/late February then as of 27 February 27th all P-40, 86th reverted to all A-36. 79th FG ceased using P-40 22 April 1944. Given all the non bombing missions run the following is only a rough guide, average bomb loads carried per sortie, A-36 0.4, P-40 0.28, P-47 0.43 tons. Whatever the theoretical limits the USAAF P-40 were on average carrying around a 500 pound bomb.

Things become more complicated from September 1944 as the 12th Air Force was split between France and the Mediterranean, until the units in France were officially absorbed into the 1st Tactical Air Force. Finally 27th and 86th FG ceased operations in theatre on 19 and 21 February 1945 being sent to 1st TAF, leaving 57th, 79th and 350th FG, the latter had arrived in September 1944. The statistics go through to the end of the war.

For a book try USAAF Jabos in the MTO and ETO by William Wolf.