P-40 vs. Zero

[Col. Sir Harry Flashman]

(my bold)
A bit on this old chestnut. The number of supercharger speeds was just a small part of reasoning to why P-40 was underperforming at some altitude belts, especially the rate of climb being poor. The P-39, P-51 and P-51A, Spitfire I/II/V and MiG-1/3 used single-speed superchargers but were faster and sometimes climbed better than P-40. The 2-speed supercharged Packard Merlin, with much greater altitude power than the early V-1710s, was unable to turn the P-40F/L into a performer. Conversely, the P-40 was sometimes out-pacing the aircraft with multi-speed supercharged engines, and sometimes even the fighters with 2-stage supercharged engines, like the F4F.
So what are the other reasons? The P-40 was heavier than most of the listed aircraft, mostly due to big (= heavy ) fuel tankage, heavy armament package from E model on, considerable strength, and useful protection. Despite all of the listed heavy items, the powerplant was barely upgraded during the life time, ie. no big V12, no 2-stage V12 (apart from prototypes), not even a big radial engine. Let's recall that a good part of Zero and Oscar performance was due to absence of protection for pilot and fuel tanks; once the protection and armament was improved on the Zero, the speed and RoC took a hit.
P-40 was a much bigger A/C than Bf 109, MC.202 or Soviet fighters, it was even biggere than the Fw 190 - size matters here, and big weight does make aircraft under-perform. Again, conversely the still bigger Hurricane and F4F were in further peformance disadvantage, despite the engines of better power above 10000 ft.
So unless the P-40 gets the 2-stage supercharged V-1650 or V-1710, or the protection, firepower and range are sacrified, it will remain underperformer from 1941 on.

I know all about the Weight to H.P. ratio problem & that the U.S.A.A.C. Brass Hats just kept piling on the weight w/o properly upgrading the engines in the P-40's to compensate for it. The U.S. Navy Brass Hats did the same thing to the Brewster Buffalo F2's as well, so badly in fact, that the Landing Gear had to be Strengthened & the Finns were the only users of B-339's that saw the stupidity of it & did something about it. so much so that the majority of the Finnish Aces got their triple Ace-hoods flying the B-339's against what ever Fighters the Soviets threw at them.

One of the first things Gen. George's F.E.A.F. pilots did after the initial attack by the I.J. Air Forces, was to lighten their P-40's by removing the O2 systems (they couldn't get to the altitude of the Betty's & the Oscars always came down to play), the Radio Gear (the radio towers were all destroyed during the 1st air raid, so no comm at all including advanced air raid warnings via radio), 2 of the 6 .50's in the E's (Oscar's flamed nicely w/ just 4 .50's) & used bare minimum Armour for the protection of the pilots.

If Gen. George had not been killed by a Ground Looping A/C just as he was disembarking from the C-47 that had flown him & his hand picked U.S.A.C.C. Officers flown out of Mindanao, he would had Championed for the Field Mods that his Pilots & Ground Crews had come up w/ to make the P-40 Lighter, have a better Climb Rate & be able to Turn Inside the Axis Fighters.
It is also my understanding from my 20+ years of research by reading everything I could get my hands on, along w/ what I've found on the 'Net, that some of the M.T.O. Squadrons of the R.A.F./Commonwealth & U.S.A.C.C. pilots & ground crews experimented w/ this as well. What the Brass Hats didn't know, wouldn't hurt them.

 

[tomo pauk]

I know all about the Weight to H.P. ratio problem & that the U.S.A.A.C. Brass Hats just kept piling on the weight w/o properly upgrading the engines in the P-40's to compensate for it. The U.S. Navy Brass Hats did the same thing to the Brewster Buffalo F2's as well, so badly in fact, that the Landing Gear had to be Strengthened & the Finns were the only users of B-339's that saw the stupidity of it & did something about it. so much so that the majority of the Finnish Aces got their triple Ace-hoods flying the B-339's against what ever Fighters the Soviets threw at them.

Indeed, the 'Brass hats' were trying to stick, weight-wise, almost about as much on the P-39 and P-40 as it was the case with P-38 that have had twice the power, and perhaps three time the power above 20000 ft. The new engine models were being installed as they became available, but it was not enough vs. Luftwaffe, even if it was against the Japanese.
The USAAF neglection of (X)P-51 was also a factor why the P-40 went into combat well after it's sell date. Ditto for not having the second source of P-38s.

One of the first things Gen. George's F.E.A.F. pilots did after the initial attack by the I.J. Air Forces, was to lighten their P-40's by removing the O2 systems (they couldn't get to the altitude of the Betty's & the Oscars always came down to play), the Radio Gear (the radio towers were all destroyed during the 1st air raid, so no comm at all including advanced air raid warnings via radio), 2 of the 6 .50's in the E's (Oscar's flamed nicely w/ just 4 .50's) & used bare minimum Armour for the protection of the pilots.

Thank you for pointing to the Gen. George.
The FEAF rarely encoutered Oscars, their main opponent were Zeroes. Unfortunately, trying to strip the P-40s from those items lowers their combat value vs. LW had it been atempted, even if it will be workable in some instances. No radios = no communications between pilots (and ground control, moot point here). The Japanese learned hard way just how radios were useful during the Battle of Midway. Indeed, the Zeros in 1941-43 were vulnerable to the MG fire.

If Gen. George had not been killed by a Ground Looping A/C just as he was disembarking from the C-47 that had flown him & his hand picked U.S.A.C.C. Officers flown out of Mindanao, he would had Championed for the Field Mods that his Pilots & Ground Crews had come up w/ to make the P-40 Lighter, have a better Climb Rate & be able to Turn Inside the Axis Fighters.
It is also my understanding from my 20+ years of research by reading everything I could get my hands on, along w/ what I've found on the 'Net, that some of the M.T.O. Squadrons of the R.A.F./Commonwealth & U.S.A.C.C. pilots & ground crews experimented w/ this as well. What the Brass Hats didn't know, wouldn't hurt them.

Soviets were also renown (notorious?) for stripping parts from the Western aircraft they got, in order to achieve a gain in performance, mostly in rate of climb. Gen. George was flown by Lockheed C-40 to Darwin.

 

[Shortround6]

Oh boy..........

"the Finns were the only users of B-339's that saw the stupidity of it & did something about it. so much so that the majority of the Finnish Aces got their triple Ace-hoods flying the B-339's"

Finns didn't do much of anything, they flew B-239s, which were the F2A-1 released from navy contracts for early delivery to Finland.
The Finns didn't take out the armor, self sealing fuel tanks, geared engines or big propellers. the Planes never had them. The weight additions didn't happen until later models which the Finns never got. Finns did add rudimentary back armor.

I wonder what the internet hue and cry would be today if the "Brass Hats" had sent hundreds or several thousand US and British pilots into combat in fighters without self-sealing tanks, bullet proof windscreens and pilot armor????

As to lighting up the P-40 by leaving things out.
Oxygen system on a P-40C.................93lbs
radio/communications P40E.................74lbs
BP glass and armor....P-40E...............111lbs
Pair of 50cal guns on P-40.................160lbs
ammo for the extra guns......................141lbs

 

[fubar57]

 

[pbehn]

As I remember from posts here Hurricanes were sent to France without armour and not all fuel tanks could be made self sealing, although there wasnt much of a hue and cry with the public pilots installed armour themselves against advice about CoG issues.

 

[Greg Boeser]

In 1939, the only fighters that had armor installed were Soviet I-16s. Armor began being installed in most western fighters in 1940.

 

[Shortround6]

What the standard of protection was for American, British and German fighters in 1939-40 and what it was in late 1941/early 1942 (when the Americans were engaging the Japanese) are two rather different things.

 

[Shortround6]

I would also note that there were two attempts to lighten the P-40. Some of the Merlin powered "L" model were referred to as the "Gypsy Rose Lee" model after a famous strip tease artist of the time. Mainly two .50s taken out and ammo somewhat restricted four the other four. One fuel tank taken out, perhaps a few other small changes. The early N models were a somewhat more serious attempt. Which was enabled by the development of aluminium radiators and oil coolers instead of copper ones, the use of magnesium wheels, the usual pull two guns and restrict ammo, the elimination of the forward fuel tank and the change to a manual starter (no electric start) and either a smaller battery or no battery. These changes were of such importance to P-40 performance in the field that some of the using units ( and there weren't that many of these stripper models built) added the batteries and electric starters back in along with the forward fuel tank and in some cases the No. 5 & 6 guns.
Oxygen equipment was a "option" on later P-40s and when used had to counted as part of the payload.
I would note that taking out the oxygen equipment in P-40s used by the FEAF was also possible or allowed because the oxygen equipment plant for filling the O2 tanks was either defective or none operational for much of the campaign, in any case O2 was not available at any of the alternative air fields according to some accounts.
Pulling the O2 equipment from the fighters if they had oxygen supplies is hardly an example of brilliant front line thinking since it means you have zero chance of intercepting the bombers which is the primary goal. "Playing" with the fighter escort while allowing the bombers to bomb unmolested is hardly a good long term tactic for air defense. In other theaters (or in the far east at later dates) the P-40s could be flown without O2 equipment because the "Brass hats" were also supplying other O2 equipped fighters to fly either top cover for the P-40s or to perform the high altitude intercepts. Comparing use of P-40s when being flown from bases where there were Spitfires or F4Fs or P-38s/P-47s to provide top cover to earlier days when it was P-40s or nothing (P-40s and Hurricanes) doesn't take into account the full situation.

 

[grampi]

I couldn't see a P-40 being preferred over a P-51 for any reason...

 

[Balljoint]

Maybe it's another thread; but I've long been curious as to how the P-40's bastard offspring, the P-51, attained its performance despite being a bit porky. Of course the high altitude zip came from the Merlin 2x2 supercharging. And sleeker aerodynamics helped. But the Mustang seemed to be able to more or less deal with the much lighter LW fighters in hairball mode. And to do so with enough onboard fuel to get home while toting maybe a ton of extra tare weight.

 

[Shortround6]

"And sleeker aerodynamics helped"

A LOT. A P-51 using an Allison engine, the same dash number as used in a P-40E, was 40-50mph faster at most altitudes.
This means, at any given speed, the P-51 had more surplus power to put towards climbing or sustaining speed in a turn.

 

[tomo pauk]

Maybe it's another thread; but I've long been curious as to how the P-40's bastard offspring, the P-51, attained its performance despite being a bit porky. Of course the high altitude zip came from the Merlin 2x2 supercharging. And sleeker aerodynamics helped. But the Mustang seemed to be able to more or less deal with the much lighter LW fighters in hairball mode. And to do so with enough onboard fuel to get home while toting maybe a ton of extra tare weight.

Bastard offspring?? The P-51 have had nothing to do with P-40, bar engine and armament. The aerodynamics applied on the P-51 were one, if not two generations ahead, and that shows.

 

[pbehn]

"And sleeker aerodynamics helped"

A LOT. A P-51 using an Allison engine, the same dash number as used in a P-40E, was 40-50mph faster at most altitudes.
This means, at any given speed, the P-51 had more surplus power to put towards climbing or sustaining speed in a turn.

It also means that you can break off when disadvantaged, I have never read of P51s forming Lufbery circles.

 

[pbehn]

Maybe it's another thread; but I've long been curious as to how the P-40's bastard offspring, the P-51, attained its performance despite being a bit porky. Of course the high altitude zip came from the Merlin 2x2 supercharging. And sleeker aerodynamics helped. But the Mustang seemed to be able to more or less deal with the much lighter LW fighters in hairball mode. And to do so with enough onboard fuel to get home while toting maybe a ton of extra tare weight.

How does the P51 come to being referred to as the bastard offspring of the P40? It was specifically designed to be better than the P40 and it was, as Tomo has said it was 2 generations ahead in aerodynamics. Don't be fooled by the P51s apparent bulk, the cooling system was a major part of its low drag set up.

When the P51 was used as an escort just by getting into a "hairball" even without making a kill it has done its job.

 

[Robert Porter]

Two most favorite WW2 planes for me are the P-38 and P-51. I like the P-40 as well but they are in no way I can tell related.

 

[Balljoint]

My thought was that Great Britain was in the market for P-40s. NAA, finding little interest in B-25s, upsold the British on an "improved" P-40, provided the improved model could be rolled out in 60 days as I recall. The "improved P-40" i.e. P-51 airframe did roll out on schedule, but took a good bit longer to fly, and even much longer to find its niche.

While the P-51 was sleek and had a laminar flow(ish) wing, the gross weight would seem to impose a substantial induced drag penalty. But I'm not arguing with proven success.

 

[pbehn]

My thought was that Great Britain was in the market for P-40s. NAA, finding little interest in B-25s, upsold the British on an "improved" P-40, provided the improved model could be rolled out in 60 days as I recall. The "improved P-40" i.e. P-51 airframe did roll out on schedule, but took a good bit longer to fly, and even much longer to find its niche.
While the P-51 was sleek and had a laminar flow(ish) wing, the gross weight would seem to impose a substantial induced drag penalty. But I'm not arguing with proven success.

The British ordered and received 620 Mustangs (P 51A) and would have liked more. The Allison engine limited their effectiveness in Europe because a Bf109 could always climb out of trouble. The gross weight due to a larger air frame was due in part to its single major advantage over other fighters, it had a large internal fuel load and room to crowbar even more in. Even without extra internal and external tanks it became the first allied single seat fighter to fly over Germany.

 

[tomo pauk]

The British ordered and received 620 Mustangs (P 51A) and would have liked more. The Allison engine limited their effectiveness in Europe because a Bf109 could always climb out of trouble. The gross weight due to a larger air frame was due in part to its single major advantage over other fighters, it had a large internal fuel load and room to crowbar even more in. Even without extra internal and external tanks it became the first allied single seat fighter to fly over Germany.

Sorry to be a nomenclature Nazi, but Mustang (or Mustang I) = P-51.
The Mustang II = P-51A.
NAA was 1st producing the Mustang I, then A-36, then Mustang II. The Mk.II (has drop tanks, less guns, better engine, better performance) went into action in Sept 1943, more than a year after the Mustang I.

 

[pbehn]

Sorry to be a nomenclature Nazi, but Mustang (or Mustang I) = P-51.
The Mustang II = P-51A.
NAA was 1st producing the Mustang I, then A-36, then Mustang II. The Mk.II (has drop tanks, less guns, better engine, better performance) went into action in Sept 1943, more than a year after the Mustang I.

For a nomenclature nazi the Mustang/P51 is very fertile ground, machines were ordered by the British who then ran out of money and Lend Lease kicked in and then Peral Harbor happened. Some changes of identity seem to me to be purely to do with who pays.

Anyway......for a bastard child it turned out quite well.

 

[Shortround6]

First 620/618 were paid for by the British had -39 (8.80 supercharger gear) engines, four .50s (two in fuselage and one in each wing) and four .303s.
then came 150 lend lease P-51s with -39 engines but four 20mm cannon. 57 were kept by the US after Pearl harbor.
Then came the 500 A-36As US paid for and operated by the US. Had the -87 engine (low altitude) and two .50s in fuselage (like the Mustang I) and four .50s in the wing.
Followed by the 310 P-51As with -81 engines (9.60 supercharger gear) and just four .50 cal guns in the wing, British got 50 lend lease.
Nomenclature tells you engine and armament in addition to who paid.

Was only a bastard child in the sense that the USAAF looked at it as NIH. British wanted all they could get and were still operating 2 squadrons of Allison powered planes at VE day. Last Allison powered Mustang left the production line two years earlier. Not bad for a bastard child

BTW, the British got 1826 (?) Merlin powered Mustangs lend lease, does not include 100 sent to Australia as kits.