Wednesday, March 7, 2007

Propeller Torque Effect

So for a while now, I guess since I built the new sim rig, I noticed everytime I'd take off my Cessna would veer to the left. For a few days I figured this was due to the yoke/peddles needing calibration. So today, I calibrated them, and calibrated, and calibrated. No luck. Still, heads to the left.


Then, I remembered about engine propeller torque. And to confirm what I remember from so long ago, found on this post:


"Torque effect is the influence of engine torque on aircraft movement and control. It is generally exhibited as a left turning tendency in piston single engine propeller driven aircraft.

According to Newton's law, "for every action there is an equal and opposite reaction," such that the propeller, if turning clockwise (when viewed from the cockpit), imparts a tendency for the aircraft to rotate counterclockwise. Since most single engine aircraft have propellers rotating clockwise, they rotate to the left, pushing the left wing down.

Typically, the pilot is expected to counter this force through the control inputs. To counter the aircraft roll left, the pilot applies right aileron.

It is important to understand that torque is a movement about the roll axis. Aileron controls roll. Prop torque is not countered by moving the rudder or by setting rudder trim. It is countered by moving or trimming the aileron.

This correction induces adverse yaw, which is corrected by moving or trimming the rudder (right rudder).

On aircraft with contrarotating propellers (propellers that rotate in opposite directions) the torque from the two propellers cancel each other out, so that no compensation is needed."

To further backup the theory that Flight Simulator was actually doing this, I googled "fs2004 torque effect" and found this post:

http://flyawaysimulation.com/postt25992.html

Which confirmed that yes, my left banking is single engine propeller torque, cool!

(Note: Someone in that post mentioned you could "Press 5" to correct it) But since I want it to be a realistic as I can possibly make it, I'll let it torque left and use right airleron to compensate.

Matt

VATSIM Pilot, USA-W
Coral Airlines, N324CR
Pilot ID: 908853

No comments: