My understanding of the Rabe Rudder is the variable rudder will counter act the gyroscopic precession caused by the rotating mass we call the propeller. Please don't ask be to explain Gyroscopic precession, I completely lack the physics knowledge to explain it.
The amount of force generated by the gyroscopic precession is really not a function of the diameter of the prop but the mass of the prop. That is to say an 11 inch wood prop might have less mass than an 11 inch composite prop or vice versa.
Anyway the rudder is only need in the pitch down motion. In pitch up the gyroscopic precession will tend to yaw the plane to the right, which in our counter clock wise flying is a good thing. But when the plane pitches down the yaw will be to the left, as in toward the pilot. This is where you want the right rudder to kick in, and is the reason for all the asymmetrical control linkage the Rabe Rudder requires. Again a Nobler with a .35 using a light prop probably won't benefit much from a Rabe Rudder. On the other hand a large plane with a big motor swinging a heavy prop could benefit quite a bit.
I also seem to remember Mr. Rabe saying that the final rudder deflection can only be determined by flying and observing how much counter yaw is required from the rudder.
Andy
Topic: Installing Rabe rudder on ARF Nobler (Read 3100 times)