P-39 program originally intended to use turbosupercharged Allison engines; however, during the design phase, the turbocharger was dropped as a drag reduction measure. Whether this was actually necessary or not, remains an open question.
P-38 did, however, use turbosupercharged Allison engines, and considering the immense technical difficulties they had in the ETO, it could be argued that the P-39 with turbosuperchargers would not have been as useful in Europe as it ended up being specifically flown by the Soviet VVS. The P-38's in Europe suffered from various problems, including sensitivity to cold weather, sensitivity to fuel quality, design flaws in the engine manifold that resulted in poor air-fuel mixture regulation, all of which could cause detonations and thus cause the engines to wear fast, and also caused engine failures directly.
On the other hand, turbosupercharged P-39's could have had a huge impact on the mid-war Pacific campaign, since on the Pacific theatre the P-38's with turbosupercharged engines proved easier to maintain and were quite effective.
If someone does put together a "prototype" P-39 with turbosupercharged engine, I believe the P-38 engines would offer a good starting point as far as engine performance goes. Of course the 3D model should be updated to include the supercharger intake, and I have really no idea what that might have looked like.
The P-63C already uses a very powerful Allison V-1710-117 engine, which had, in addition to the standard single-stage supercharger that all Allison-powered aircraft had, a second remote supercharger operated by hydraulic clutch, which engaged as the boost pressure dropped below certain limit (wiki says it engaged at 3000 metres or so, depending on atmospheric conditions). This added about 3000 metres to the service ceiling and obviously significantly improved the high-altitude performance. P-63 was never intended to have a turbosupercharged engine; however, there was an intended variant (P-63B) that was to use a Packard Merlin engine. Due to the unavailability of Merlins (their production was mainly allocated for the P-51's for obvious reasons), this variant was cancelled.
Additionally, if someone feels like fiddling around, after the war, Bell modified two P-63's to swept-wing variants called L-39, under contract with US Navy, for the purpose of low-speed and stall testing of high-speed, swept wing design. I do not know what happened to either of those airframes or how they fared in testing, but they look kind of cool.
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Topic: P-39/P-63 with turbocharger (Read 2805 times)
