I agree with Lumpy. Inverted stalls are more difficult to recover from. By the video, the pilot was not able to recover enough airspeed to pull out of the stall. It is very hard to get the nose down when there is little airflow over the tail surface, which is what he had when this aircraft stalled. As to the aft mounted engine, that has nothing to do with how the aircraft recovered or lack of recovery. Remember, the aircraft rotates around its Center of Gravity. As long as the CG is within limits, there will be no issues if the aircraft stalls. Even if the aircraft is in 45 or 60 degree bank, as long as the ball is centered, it will not spin. Have done this countless times in C-172s and other aircraft. Now I will grant that the CG for the P-39 is more aft than normally seen in aircraft. But as long as the CG is within limits and at a safe altitude, the pilot would have been able to recover. Toward the end of the video, the aircraft is starting to recover, but the altitude is not sufficient enough to allow it. He also stalls a second time as evidenced by the abrupt roll to the right as he is diving to regain airspeed. We may not know if the CG was within limits, I would hope that the pilot was professional enough to check that, but if the airspeed had been high enough, we would not have seen this video.
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