Peter Gunn
Master Sergeant
What Buffnut said. You do realize we're not talking about swapping out a couple of small block Chevy's in a Camaro right?
Groundhog Thread Part Deux - P-39 Fantasy and Fetish - The Never Ending Story (Mods take no responsibility for head against wall injuries sustained) (2 Viewers)
- Thread starter greybeard
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Peter Gunn
Master Sergeant
Those would be great if they were sort of legible.
However, I think I see what you're driving at.
P-39 Expert
Non-Expert
Especially since the highest power setting was not available for most of the war.
P-39 Expert
Non-Expert
Low production engine? Same engine as contemporary 1710 models, only real variables were S/C gear ratios and E model remote reduction gear. The only new production item was the auxiliary stage which was just an impeller in a diffuser driven by a small shaft. It's not like Allison just trucked over the first -93 engine to the Bell plant and said "Surprise!" Bell had known for literally years that this engine was coming, prep work would have been done to insure as smooth a transition as possible.
Regarding cooling, as you say we have discussed this before. Just a 1325HP Allison with a higher critical altitude. I know I know the air is less dense at high altitude but it is a lot colder too. This engine was only put into a P-39E three times but I believe it could have been done. Dead horse beaten.
And the P-39 wasn't the only AAF fighter that had cooling problems. From wwiiaircraftperformance.org the P-38G tested 2/10/43: "Prestone cooling does not meet Air Corps cooling requirements." This is in addition to the intercooling deficiencies. From the P-47 tests of 6/18/42, 12/26/42 and 1/28/43: "Above speeds are for maximum rate of climb, but the engine does not meet the AAF cooling requirements at these speeds." And this is at very mediocre climb rates. P-51A test 4/2/43 didn't meet Air Corps cooling requirements in speed or climb. 6/11/42 test: "cooling temperatures were 7 degrees warmer than the maximum temperature allowed." P-51B test of 4/24/44 said "coolant temperature would be critical throughout the climb in a range of 120-135 degrees." All the AAF fighters had cooling problems except the P-40 as far as I can tell.
By late 1942 the USA had P-47, P-38 and P-51A, the UK had the Spitfire IX and the first Griffon variant the MkXII. In what role is the P-39N better than those and was it competitive with the Fw 190A-6 at all altitudes?
P-39 Expert
Non-Expert
P-39N was competitive with late 1942 P-38F/G, P-47B/C and P-51A. Yes it was.
The FW190A-6 vs P-39N graphs are graduated by altitude. Better climb and ceiling.
If the P-39N was a match for the Fw-190 at all altitudes then the P-51A would be an ideal long range escort, wouldnt it?
P-39 Expert
Non-Expert
Sure, for medium bombers but not high altitude B-17 or B-24. P-51A didn't have the climb and ceiling of the P-39N since it was 1000lbs heavier with the same engine.
Better to send whole fleets of bombers unescorted then rather than try it, why not reduce the altitude of B-17s? The P-39 was sent away from UK after 1 mission, the P-40 was sent to N. Africa after a few dozen, the Mustang MkI was used for tactical recon. This is all because the Allison engine didnt have high altitude performance and neither did the P-39N. This is why the P-38 had turbos and the P-51 got a two stage Merlin, to pretend otherwise is just denial.
Gentlemen
Granted, the opinion expressed below was from a pilot in the PTO. However, I think we are missing the whole point of why the P-39 was not valued by the USAAF:
"It took no time to realize that I had a poor combat airplane. It had served its purpose well in Panama, but this was a brand new ball game. The P-39 had no range to get you where the real action was, poor service ceiling, poor rate of climb, and it wasn't the best in a dive." Capt W.K. Giroux, quoted from Pacific Sweep page 232. (Italics by me)
Granted, he was talking about early P-39 and P-400's that were well used for the most part, and he was stationed with the 36th fighter Squadron, 8th Fighter Group in Port Moresby New Guinea. However, he had some 30 missions in the P-39, so his opinion should carry some weight.
In my opinion, stuff what ever more powerful engine you can into the P-39, adjust the weight to keep proper CG, but without extra fuel, you will still have a fighter that has "no range to get you to the real action".
So I agree with the consensus, adding a more powerful engine will not be a simple switch. It appears to me to get the most out of a more powerful engine, it makes more sense for a new airframe. Bell did this with the P-63. However, the King Cobra was still hampered by lack of range (for USAAF purposes).
My 2 cents,
Eagledad
Granted, the opinion expressed below was from a pilot in the PTO. However, I think we are missing the whole point of why the P-39 was not valued by the USAAF:
"It took no time to realize that I had a poor combat airplane. It had served its purpose well in Panama, but this was a brand new ball game. The P-39 had no range to get you where the real action was, poor service ceiling, poor rate of climb, and it wasn't the best in a dive." Capt W.K. Giroux, quoted from Pacific Sweep page 232. (Italics by me)
Granted, he was talking about early P-39 and P-400's that were well used for the most part, and he was stationed with the 36th fighter Squadron, 8th Fighter Group in Port Moresby New Guinea. However, he had some 30 missions in the P-39, so his opinion should carry some weight.
In my opinion, stuff what ever more powerful engine you can into the P-39, adjust the weight to keep proper CG, but without extra fuel, you will still have a fighter that has "no range to get you to the real action".
So I agree with the consensus, adding a more powerful engine will not be a simple switch. It appears to me to get the most out of a more powerful engine, it makes more sense for a new airframe. Bell did this with the P-63. However, the King Cobra was still hampered by lack of range (for USAAF purposes).
My 2 cents,
Eagledad
P-39 Expert
Non-Expert
See the chart in post #869. 38000ft ceiling and 31000ft combat ceiling. Better than P-40, P-51A, F4F, F4U, F6F, FW190, Typhoon, A6M2 and Ki-43. About the same as P-38F/G, P-47C and Me109G and better climb below 30000ft. Not as good as Spitfire IX. That about covers it for 1942/43 fighters.
P-39N had a higher rated engine than the vastly overweight P-400s rejected by the UK.
P-39N had a higher rated engine than the vastly overweight P-400s rejected by the UK.
P-39 Expert
Non-Expert
Agree with most of what you said. 1942 P-39 was way too heavy for the engine power available. Dump the wing guns, nose armor plate and IFF radio and a 7150lb P-39 would have done whatever the Captain asked. Endurance was actually over 3 hours which was better than single seat European fighters and enough to conduct operations in New Guinea that were mostly defensive in 1942.
It did make sense to design the new P-63 around the new engine, but it did not make sense to waste seven months in the middle of 1943 waiting on the airframe to be finished.
So he people there at the time were wrong then? Like many you underestimate the effect of that 21 miles of water. What worked in Africa and Russia didnt work across that stretch of water, and after D-Day altitude performance wasnt so important, neither was range, although it is 21 miles at the shortest point it quickly becomes 100.
P-39 Expert
Non-Expert
I don't understand your comment about overwater flights.
FLYBOYJ
"THE GREAT GAZOO"
The AAF was not going to dump the IFF in operational units, so drop that, and depending on radio configuration, you cannot remove the armor plate in the nose as been shown over and over again! I have some more data coming to include Russian P-39 configurations.
And speaking of IFF - you have said that the Russians "removed" their IFFs. An IFF was a sensitive unit and even had a destruct system built into it. Do you have an accurate source to say the Russians were "removing" their IFFs or were P-39s were being delivered with IFFs not installed?!
Glider
Captain
and lose valuable firepower
And be shot to bits by anyone with an LMG. Put it another way. I can think of loads of aircraft who added armour for protection but cannot think of any that took armour out. P39 do you have any examples?
And suffer much higher losses as they normally had other functions such as identifying aircraft lost in bad weather. Helping your side sort out who was friendly and who wasn't. Again to put it another way. Why do you think it was installed in the first place?
]
Well then I suggest you read about it and think about it. The Channel is a DMZ or no mans land, both sides have to cross it and both sides had heavy AA on the coast, you can cross at sea level if you want but that means you can be bounced at zero feet. Apart from heavily defended ports there is little of interest on a coast, it is completely different with a land front, as in Russia and the east, N Africa and France Italy after landings had been made, the fighting on the ground and providing CAS drags the conflict down to ground level, higher altitudes covering for CAS operations.I don't understand your comment about overwater flights.
According to Wiki the Russians were still telling Bell to put more armour in and move the cannon forward in the P-63 in 1944. From start to finish Bell and yourself dont grasp that armour and other equipment werent there as ornamental and pretentious frippery.
FLYBOYJ
"THE GREAT GAZOO"
P-63A-8, SN 269261, was extensively tested at TsAGI in what was then the world's largest wind tunnel. Soviet input was significant. With the Soviet Union being the largest buyer of the aircraft, Bell was quick to implement their suggestions. The vast majority of the changes in the A sub-variants were a direct result of Soviet input, e.g. increased pilot armor and fuselage hardpoint on the A-5, underwing hardpoints and extra fuel tanks on the A-6, etc. The Soviet Union even experimented with ski landing gear for the P-63A-6, but this never reached production. Most significantly, Soviet input resulted in moving the main cannon forward, favorably changing the center of gravity, and increasing its ammo load from 30 to 58 rounds for the A-9 variant. The P-63 had an impressive roll rate, besting the Americans' P-47, P-40, and P-51—and the Japanese Navy's Kawanishi N1K2 Shiden-Kai fighter—with a rate of 110° per second at 275 mph (443 km/h).
Dean, Francis H. America's Hundred Thousand. pp. 410, 602
Dean, Francis H. America's Hundred Thousand. pp. 410, 602
P-39 Expert
Non-Expert
We'll have to disagree on the nose armor. It certainly could be removed if other adjustments were made. The 20mm cannon was 140lbs lighter than the 37mm cannon and Bell made adjustments for that. The nose armor only weighed 71-100lbs.
You don't need IFF if your base doesn't have radar. Port Moresby didn't get American radar until fall 1942. If you have not been detected on radar then you don't need to identify yourself as friendly. I'm only advocating removing the IFF sets in 1942. After then, when radar is available, the IFF radios, nose armor and 30cal wing machine guns can remain because the P-39 will have the uprated -85 engines. Again: Lighten the 1942 P-39D/F/K/L, not the more powerful 1943 M/N.
I have read numerous times about the IFF radios being deleted by the Soviets along with the wing machine guns. They never deleted the nose armor that I am aware of.
