Brian,

I beg to differ regarding gyro-p and p-factor. Gyro-p is very likely in play as the aircraft has very recently if not actually in the process of raising the tail; p-factor is in play as the aircraft is in a tail-low, positive angle of attack.

Maybe the forces involved in gyro-p and p-factor are not that great, however. The info at this link state: "Wind tunnel research on conventional single-engine aircraft indicate that about 6/7 of the total yawing moment is produced by the spiraling slipstream..." Unfortunately, the article itself shows no citations.

Thanks,

Bill