Mounting a hitec 5945 in the tail of a WH Edge. Do I need a SWB 1 1/4 arm to get the max throw?

It depends on the length your horn is set to. Use arm length/horn length=ratio of deflection. If you use a 1.25" arm and a 1.5" horn length then surface deflection degrees = 1.5/1.25* servo rotation.

In this case if the servo rotates full 60 degrees then surface deflects 1.5/1.25*60=50 degrees of deflection.

A longer arm puts more stress on the servo and gears.

TF

A 1-1/4" arm is just perfect.

Too much math?

TF

Yep, throw meter ; )

Thanks for the help. I like simple control rods. I have used the carbon fiber 4-40 rods from central hobbies alot, and like them.... Tom's method seems to be just as strong.... and cheaper... and easier to install....

Stronger IMHO. When pulling the CH pushrods depend on a glue joint, ours are pulling against a steel rod all the way through. And when pushing ours have steel reinforcing the tube, theirs have only the tube.

TF