Engine torque is the torque that the engine applies to the drive shaft to turn the propeller.
Propeller torque is the torque that is caused by the rotational drag as the propeller turns. The propeller torque opposes the rotation of the propeller.
As the TAS increases during the take-off run the angle of attack of the blades decreases. This decreases both the thrust and the propeller torque. If we assume that the engine torque has not changed, then the engine torque will be greater than the propeller torque. So the RPM will tend to increase. If it is also a constant speed prop the CSU will sense this tendency and will increase pitch angle to prevent it.
Last edited by keith williams; 28th July 2011 at 15:06.