Well,
I keep following this thread with great expectation and interest. All of your comments are being very important and have already contributed to some judgement regarding the real need for aileron (and not only rudder) trim on prop / turboprop aircraft operations, single or twin (with non counter-rotating props), and under normal situations (no asymmetry due to differential thrust/engine failure, fuel imbalance, etc...).
A few pilots I was meanwhile able to talk to, mentioned that only rudder trim is used, because yaw and not bank is the main / perceptible effect of the "family" of prop effects (torque (engine inertia + airflow drag), p-factor, slipstream asimmetrically hitting various aircraft surfaces, gyroscopic effects). Other pilots acknowledge the need to use aileron trim under various phases of flight to be able to "fly hands off"...
On the particular source I am using, unfortunately not real life experience but rather a PC-based simulator, the bank from torque is very considerable, most probably because the asymmetric hit of the wings & tail surfaces is not fully modeled, which could account for some forces to counter the torque effects - spiraling slipstream hitting the left wing from bellow, thus tending to counter the left roll tendency assuming clockwise running props...
I look forward for even more posts :-)
Thank you very much you all :-)
Last edited by jcomm; 13th Sep 2012 at 17:02.