New member here, where in hell did you get the graphs above?
Been looking for that stuff for a long time! Is it available for other aircraft?
I have been looking for just such a comparison, but, of course, the altitude makes all the difference. Superchargers and turbochargers made a huge difference in the performance of the various airframes.
Example was the P-39. WITH the turbocharger it was world beater. Without the turbo, it was a world beater below 12 to 15 thousand feet, but was miserable above that altitide.
So the Soviets kicked ass with the P-39 while WE didn't use it much unless we HAD to.
So ... where are all these performance graphs located?
I have extensive files of air kills, conflicts, and pilot names, but all are by country and name. None are by what aircraft type the pilot was flying or what aircraft was killed. Seems almost like a conspiracy of disinformation ...
Anyone HAVE these data? If so, you are the savior of all WW2 aviation fans all over the world!
PLEASE post or send an email link!
All the NACA historical documents are available at the NASA archives:
NASA Technical Reports Server
Diasgree that the P-39 was a "worldbeater" with the turbosupercharger.
Fundamental problem is that, due to many reasons, the performance of the XP-39 couldn't really have been replicated on production machines (combined with the philisophy of the USAAF at the time didn't really favour high altitude interceptors).
The excellent 390 mph top speed and 5 minutes to 20,000 feet climb figures that the turbosupercharged XP-39 achieved in testing were for an unarmed, unpainted, polished prototype without any military equipment.
The XP-39 that achieved them weighed just 3,995 lbs at empty (only 200lbs heavier than an empty A6M Zero and more than 1,400lbs lighter than P-40 protoypes). If you add military equipment, like self sealing fuel tanks, military radios, antenna, armour, guns, gunsights, gun heaters, ammunition, IFF and all the other stuff necessary to make the plane a workable fighter, performance is going to take a nose dive.
Aerodynamics get messed up by airframe projections (gunports, antenna, ejector chutes, ect) and camoflage paint. The RAF found they lost 7 mph in top speed at sea-level from the its Allison engined P-51s after painting them.
Just to give an idea of how much weight creep there would be; The empty weight of the YP-39 was 5,040 lbs, up just over a 1,000 lbs from the 3,995 lbs of the XP-39. That's a weight gain of just over 25% on the empty weight AFTER stripping out the turbosupercharger.
Loaded weight shot up from 5,550 lbs for the unarmed XP-39 prototype to 7,070 lbs for the armed YP-39, and it was still without internal or cockpit armour and had no self sealing fuel tanks. When these, and more guns and ammunition were added, combat weight climbed by another 500lbs.
So, a fully loaded, combat capable P-39D circa September 1941, weighed around 7,650 lbs combat loaded, almost a full 2,100lb heavier than its turbosupercharged XP-39 ancestor. That is a weight gain of about 38%. Its empty weight was 1,400lbs higher than that of the XP-39 prototype. That increase would markedly effect handling, speed and climb performance.
Would the P-39 have been better a better fighter in the ETO and Pacific if the USAAF had left it alone? Yes, but probably not by much. It would of been marginally slower and less manouverable down low, but progressively faster above 15,000 feet. Its problems with CoG and cannon reliability would of still existed.
To turn the P-39 into a combat capable fighter it needed all that equipment. So, the weight creep, that was always going to happen, meant that the performace exhibited by the prototype wouldn't of been achievable in real life until there was a serious jump in power in the military models.
