P-39 vs P-40

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gjs238

Tech Sergeant
1,889
329
Mar 26, 2009
In the Which aircraft would you cancel? thread there was some support of the P-39.
So why was the P-39 so favored in USSR, yet the P-40 so favored by the US, Britain, etc?
 
Kind of depends on when. In 1941 the P-40 is the ONLY mass produced fighter the Americans have, Ok they built 926 P-39s but Curtiss built 2248 P-40s. And all the other fighters put together don't even equal the P-39 production.

Unless you kill the P-39 in the cradle and have Bell tool up for P-40s in the fall of 1940 (Bell didn't hit 50 planes per month until July of 1941) shutting down Bell and and having them make anything else is going to leave you hundreds of fighters short in the early years of the war. Bell could crank out 200-300 P-39s a month in good months. Taking them out of production to switch over to any other fighter type isn't an option until mid to late 1943.

The P-40 is pretty much the same only more so. It is not until the last few months of 1943 that P-47 production passes P-40 production. P-51 production doesn't exceed P-40 production until the Spring of 1944 and at that point P-40 production is winding down.

As to which was favored by who? From Late 1942 onward the P-40 was used more and more as a bomber on average. It carried more fuel inside than a P-39 and could carry more bombs outside. With P-51s. P-47s P-38s and Spitfires flying top cover the P-40s were saddled with ever increasing bomb loads. Field expedients included three 500lb bombs, six 250lb bombs and in Italy a few squadrons used a pair of 1000lb bombs. The P-40 may have been easier to maintain. Nothing to do with the engine/gear box (although there may have been, I don't know) but the P-39 was an ALL ELECTRIC airplane (at least most of them), electric landing gear, electric flaps, electric radiator doors, electric prop pitch control, etc.
Since the Russian were NOT getting P-38s, P-47s and P-51s they may have rated the higher performance of the P-39 as more important than the maintenance problems. And even then they semi-stripped the P-39s. Stripped P-40s gave up a lot in return for not much.
 
I've ready plenty of historical pilot comments to effect that P-40 had few bad flying habits. Comments concerning P-39 flight characteristics tended to state the opposite.

Inexperienced pilots prefer predictable and safe over theoretical performance values.
 
Cancel the P-39? I don't think so. The early P-39s (especially when pushed to 66, 70 and even 72"Hg boost) had a more comparable performance to the Fw 190s and Bf 109s at low and medium altitudes. And that is why the Russians liked them so much.
 

So the P-39 was a better dogfighter than the P-40?
 
Soviets also didn't care how many pilots died from aircraft accidents such as low altitude spins resulting in a crash. USA and RAF pilots expected better from their equipment.
 
In the vertical, yes. In the horizontal, maybe not. The P-40 variants over all could out roll and out turn the P-39 variants. The P-39 had a speed and acceleration advantage though.
 
I wonder if the AVG "Flying Tigers" would have excelled with the P-39.
 
Hi Wuzak,

Yes, I'd have canclelled the P-39 and gone with the P-40. There was NOTHING in the XP-40Q that could not have been arrived at earlier had they concentrated on that rather than the entire P-39 project.
 
CORSNING said:
In the vertical, yes. In the horizontal, maybe not. The P-40 variants over all could out roll and out turn the P-39 variants. The P-39 had a speed and acceleration advantage though.
Click to expand...
Would that roll advantage hold true if the P-39's wing guns (and associated ammunition) were removed?
 
It was more a funtion of the aileron travel. The USA had a problem with specs. We only wanted our fighters to roll and pitvh so fast, and the rest of thw world was unconstrrained. If you go look at the epscs, the US fighters MET the specs for roll. If they had rolled as well as the Fw 190, for instance, they would not have been accepted for service, and would have been thought of as "too quick in roll.'
'
It wasn't that we couldn't make a good-rolling fighter ... we never specified one to be developed in the first place. Naval aircraft in particular had a lot of specs on slow-speed handling that affected their design.
 
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If you flew the P-39 within limits there were no issues. I believe both aircraft eventually had similar attrition rates especially when operated by training squadrons. The P-39 got a lot of bad press because of a customer who continually changed their mind about how they wanted to operate this aircraft and then deployed the aircraft in roles it wasn't intended to fulfill to begin with. It takes a lot to stall/ spin an aircraft, even one with a sensitive center of gravity. If one knew what he was doing the P-39 could be flown aggressively, the soviets more than proved this.
 
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Both US and Soviet airforces made good use of the P-39 as low alt strike fighter or as bomber killed (pending they did not fly too high due to engine limitations). The P-40 was made good use of as bomb truck - fast in and fast out.
Both were also used as fighters, especially in the Pacific but also in North Africa. It's there were both showed problems, especially with the Zero but also with the other more nimble fighters and bombers flying too high for their engine setup. In North Africa the appearance of german fighters and more modern italian MC.202 again made their deficits as fighter aircraft visible.
 
The more notable examples of problems with the P-39 spinning seem to be shifting loadouts and pilots with experience in one configuration having trouble in another. (mostly with nose-light loadings having problems -I'm not sure if the 20 mm armed versions were any better or worse)


GregP said:
I'd cancel the P-39 and go forward with the XP-40Q, hands down.
Click to expand...
I've been thinking more about the more dramatic revisions suggested to the Bf 109 over in the Ki 100 thread, and realized there might be some more realistic context to the 'early war P-40Q' suggestion. The engine was obviously a no-go and you'd be pretty much limited to the existing V-1710 and V-1650 powerplants the P-40 already used (and turbocharger implementation is potentially iffy too) but that doesn't mean the basic airframe couldn't be more dramatically improved in a number of areas the P-40Q later was. Curtiss seemed to spin their wheels a lot with the engineering employed on the XP-46 and XP-60 projects without much solid results and this somewhat reminds me of the issues with the Me 209 and 309 developments.

Granted, changing the design too much would mitigate advantages in continued production with common tooling advantages and such (over switching to another aircraft entirely) but the P-40Q at least seemed more in line there than the P-60 would have been and possibly P-46 as well. (managing better performance than the P-39/P-63 on similar engines would probably have been enough to merit production preference there too)
 
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It's not so much roll rate as roll rate at high speed. When the P-40 used the vertical at appropriate altitudes it had an excellent roll rate and did well against the Oscar and other dog fighters.
 
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