Same time as the Mustang MK I appeared too.
Groundhog Thread Part Deux - P-39 Fantasy and Fetish - The Never Ending Story (Mods take no responsibility for head against wall injuries sustained)
- Thread starter greybeard
- Start date
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Glider
Captain
good point
Shortround6
Major General
I think you missed the point. The Airacobras on your chart are running at 3000rpm for the first 5 minutes of their climb. The Spitfire is running at 2850 rpm instead of 3000rpm like it would do in combat. Granted the Allison didn't have a 30 min rating. It's next lower rating to military power was at 2600rpm so that wouldn't be fair either.
The Mustang Mk I blows most of the arguments out of the water, it was built and supplied to the British as a purchase and lend lease and much loved by the pilots that flew it, the engine was OK within the altitude limits known by all, the problem with the P-39 was the P-39 airframe.
fubar57
General
Ka-freakin'-boom!
Airframe was a small part of the problem, it was less draggy than Spitfire, P-40, Re.2005 or G.55.
Engine was the biggest part of the problem, and then we also have a problem of sticking 900 lbs worth of guns and ammo on a nominal 1150 HP engine.
I cannot possibly be the only person here that doesn't remember all these points being done to death in the past.
fubar57
General
Yep
The British had a use for the Mustang Mk I and would have taken more right up to end of 1944, they had no use for the P-39. Basically the P-51 could cross the channel and get back the P-39 couldn't.
I've never said they had use for P-39. P-39 was unsuitable for major use for ETO.
It certainly could.
P-39 Expert
Non-Expert
The P-51A (MkI) and the P-39N had the same engine.
P-51A was a little cleaner so it was 10-15mph faster.
P-51A weighed about 800-1000# more so the P-39N climbed better and had a higher ceiling.
P-51A had 50% more fuel so range was a good bit farther.
P-39 probably a little more maneuverable. Easier ground handling.
Armament? Who knows. P-51A had four wing mounted .50 MGs. P-39 had center fire cannon and two synchronized .50 MGs.
One is a better interceptor, one is a better escort.
Replace the .30cal wing guns and substitute 50gal fuel in the P-39 and you have about the same plane as the P-51A.
P-51A was a little cleaner so it was 10-15mph faster.
P-51A weighed about 800-1000# more so the P-39N climbed better and had a higher ceiling.
P-51A had 50% more fuel so range was a good bit farther.
P-39 probably a little more maneuverable. Easier ground handling.
Armament? Who knows. P-51A had four wing mounted .50 MGs. P-39 had center fire cannon and two synchronized .50 MGs.
One is a better interceptor, one is a better escort.
Replace the .30cal wing guns and substitute 50gal fuel in the P-39 and you have about the same plane as the P-51A.
Shortround6
Major General
Except you don't.
Four .30 cal guns = 99lbs
1200 rounds of 30 cal ammo= 72lbs
50 gallons of fuel weighs 300lbs
Weight of the self sealing tanks to put the fuel in???????
Wonder what the Mustang could do if you magicly took out 180lbs and added 400lbs of "stuff" with no penalty?
Problem being that P-51A was Mustang Mk.II, that entered service by September 1943 in MTO and CBI.
Mustang I was roughly XP-51 that is combat capable, RAF's Mustang I was in service by Spring 1942.
Mustang Ia was P-51.
Spitfire V was faster above ~15000 ft than P-39D, and climbed better at all altitudes. It will also out-climb the Mustang I, and probably be faster above 20000 ft.
Hello Drgondog et al,
I was basing my statement on comments from a pilot who had flown both the P-51B and P-51D and noted that the handling between the two machines was noticeably different. He attributed the difference to modifications required by the gun arrangement. There certainly were some other changes after the death of Col. Hitchcock in a high speed dive but perhaps they had no real aerodynamic effect.
- Ivan.
From what I gather the RAF's problem with the P-39 was that it didn't work, and not how the performance shook out a few mph/fpm in whatever direction. Reading 601 Squadron's trials and tribulations with the aircraft, they went from a very experienced unit excited for their new aircraft -- to a demoralized shell of what they were.
Engine troubles and forced-landings were so constant that 'getting a four-ship section airborne became cause for celebration'. Though they gave it everything in their power, 601 Squadron wasn't able to overcome the difficulties, which were beyond what they were capable at the squadron level and what the Air Ministry were prepared to devote to the aircraft.
Conversely -- 'It is not an exaggeration to say that Soviet pilots and engineers, front-line troops and researchers, gave their maximum effort to turn the Airacobra into a fully capable combat aircraft. And in doing so they saved the Bell firm from great unpleasantness associated with the production of a series of "unfinished" aircraft.'
Engine troubles and forced-landings were so constant that 'getting a four-ship section airborne became cause for celebration'. Though they gave it everything in their power, 601 Squadron wasn't able to overcome the difficulties, which were beyond what they were capable at the squadron level and what the Air Ministry were prepared to devote to the aircraft.
Conversely -- 'It is not an exaggeration to say that Soviet pilots and engineers, front-line troops and researchers, gave their maximum effort to turn the Airacobra into a fully capable combat aircraft. And in doing so they saved the Bell firm from great unpleasantness associated with the production of a series of "unfinished" aircraft.'
(from Airacobras Enter Combat by Valeriy Romanenko ... a lot of relevent bits online at Early Cobra's in Soviet Aviation)
Kevin J
Banned
The Brits would certainly know from May 10th 1941 that the Germans were about to attack the USSR as that is when they picked up Rudolf Hess. They probably had a good idea perhaps 6 months before that the Germans were about to attack the USSR as they had Spitfire spy planes overflying Germany and would have detected all the troop movements which pointed away from an invasion of the UK. I can't remember when we actually warned them of an impending attack. The P-400's were heavier because they had more armour and what did they do with them, they shot up some invasion barges. Maybe that's what we needed them for in the first place, but no invasion, no P-400's required.
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wuzak
Captain
Except for the P-400, the centre fire cannon was rather poor as an air-to-air weapon. And the cowl .50" hmgs fired much slower than the same gun on the P-51. Maybe half the rate?
Clayton Magnet
Staff Sergeant
- 890
- Feb 16, 2013
The Browning action did not synchronize well, I think they were in the 400-500 RPM territory
