Originally Posted by
Bozarth
I disagree. Given a somewhat symmetrical geometry, there is no need for expo...the system is proportional...20% movement of the stick moves the servo 20%, which moves the control surface 20%. 80% movement of the stick moves the servo 80% which moves the control surface 80%. The motion is rotary-translational-rotary, resulting in a linear and proportional output. The SIN function is working on both sides of the pushrod.
Kurt
No need for expo? Interesting.
Expo isn't used to make the control surface directly proportional to stick movement. It's just the opposite. Expo is used to move the control surface less than stick movement around center to make it less sensitive, which makes flying smoother.
I have my elevator throws set for 20% of full throw when flying pattern and I still use 40% expo. The other surfaces also have similar set ups in relation to full throw. Full throws are used for landing and take off and have higher expo percentages.