A few comments on P-39.
The P-39 appears to be optimized for the technology of the moment, with limited growth space, ala F-16, which had 2 sqft growth space when I did avionic installation work for the Nothrop AMRAAM proposal. With limited growth bound by size and critical Cg requirements, building a really capable fighter was difficult. They probably should have started off with a longer fuselage ala P-63, increasing the nose length and moving the pilot/engine forward moving the natural Cg forward allowing more flexibility in stability and equipment layout. This would have allowed the room for turbo or fuel or maybe both. Of course, slightly more weight, bigger wings needed?, more power?, on and on. It was quite fast compared to the P-40, F4F,and the Zero, so it had some airspeed to trade off against a bigger wing. The turbo would certainly improve performance at higher altitude. I kinda guess that they should have started off with a lightened P-63ish design.
Please remember the Allison only had 1150hp. Uprated engine or auxiliary stage supercharger wasn't available until 1943. Had to keep it small to have any performance at all.
Second, a few months ago, I read The First Team and the Guadalcanal Campaign and there was not too much derogatory comments about the P-39 except the limited high altitude ability. I it did provide quite capable close air support for the Marines. Also, General Kenney did not complain much about the plane and wanted more of them, of course, he was desperate for aircraft and really wanted P-38s.
Finally, degrading the P-39 performance in the Pacific was possibly the capability or lack thereof of the pilots. The army had a 100 new pilots fresh out of flight training enroute to the Philippines when war broke out and these were then diverted to Australia. I suspect these very inexperienced pilots had a tough time against Japans best.
This was huge. Best pilots in the world vs 100 guys fresh out of flight school. Hellcat (and even Lightning) were great planes but they never faced the Japanese first team.
I was much confused by the data on the P-39. While it has been ragged on as a second class fighter the flight test data in comparison with contemporary fighters, the P-40E and the F4F-4, and the Zero, the P-39 was significantly faster than the P-40E up to about 19k, significantly faster than the F4F-4 up to 25k (50 mph at 15k), and faster than the Zero up to 25k. In climb, the P-39 is equal to or better than both the P-40E and the F4F-4 up to 25k. The Zero is much better than the American planes in climb rate at all altitudes. So, below 15k the P-39 is quite a bit faster than both American fighters and the Zero, and below 10k, the Zero has only about 300 ft/min advantage in climb over the P-39. So, it is a low altitude fighter, but could certainly be formidable there in the hands of a capable pilot.
1942 P-39 data has always been biased. 750lbs lighter than the P-40E with the same engine and propeller it had to be faster and climb much better at all altitudes. Reduce the weight like the Russians did and it would climb with a Zero.
comes up with a similar chart or data from a different model, I'll be glad to run the numbers (and show the math). However, I don't think there's going to be much of a difference.
