Dissymmetry of Lift and the R22

[Robbiee]

According to my textbook, Dissymmetry of Lift is corrected by the teetering and feathering of the main rotor. However, I also remember being told that the trim in the R22 was to compensate for Dissymmetry of Lift. So, which is it?

Anyone know enough about the R22 to clear this up?

[SunofAtom]

Dissymmetry of lift is resolved through teetering of the rotor system. IIRC, trim is simply to hold some of the cyclic pressure while in straight and level flight, since without hydraulics, it took constant pressure to hold it.

[212man]

Originally Posted by Robbiee

According to my textbook, Dissymmetry of Lift is corrected by the teetering and feathering of the main rotor. However, I also remember being told that the trim in the R22 was to compensate for Dissymmetry of Lift. So, which is it?

Anyone know enough about the R22 to clear this up?

In the cruise you are holding the cyclic in a position to counteract inflow roll and flap back - the trim relieves some or most of that force. I believe.

edit - exactly what the POH says: https://robinsonheli.com/wp-content/.../r22_poh_7.pdf

[Ascend Charlie]

Dissymmetry of Lift is corrected by the teetering and feathering of the main rotor.

The teetering in this statement is actually flapping away from the direction of travel, and the feathering comes from the cyclic input to stop it from happening.

There are forces felt through feedback from the rotor system. In a hydraulic aircraft, these forces are not felt through the controls (unless, in a Squirrel, the forces from enthusiastic moves overpower the dismal hydraulic system). But in the Robbies, you need physical effort on the cyclic to hold it in the position you want. Pulling the trim knob on can relieve some of these forces.