RE: What's the minimum amount of torque that can be used for aileron direct drive?
I reqally shoul have said :
Trim is vague with servos which are very weak at the first degree or two of movment.
If the surfaces are LOCKED together - then the trim stays put much more easily.
Why?
for one aileron to move (thru airloads such as pitch commands), it must move the other in the opposite direction.
Tho tiny non digital servos have enough torque-after two or thre degrees of rotation, ,typically their ability to hold a "no command input" position (center)is flat lousy .