Rob Wolf,
However you attach the pitch servo rod to the elevator push rod, try to eliminate any "slop' or "dead area". My 235/320 is very sensitive in pitch control, so if you allow the push rods to rotate when control force is applied, this presents a dead area to the servo/controller,so rotate all the rod-end bearngs in one direction to minimise "slop", I attached the servo rod end bearing to the elevator pushrod with a bolt thru the servo rod end bearing, which was bent 90 deg to parallel the elevator push rod and the used two hose clamps around both to hold it parallel and tight to the elevator push rod.
The whole trick to good control is to mimic the pitch servos response to the A/C's control/altitude changes and with my S-Tec 50 it has been a battle. For the most part it is too sensitive, maintaining absolute altitude control to the foot (almost) but yanking us humans up and down rather uncomfortably.
We had added a gang switch of resistors which helped greatly, but the internal wireing kept shorting out a pico fuse in the controller, a new metal "Absolute Altitude Tranducer" has helped the transient EMF problems and a local wizard here wants a crack at it.. more later Don Skeele N320J
-------------- Original message from rwolf99@aol.com: --------------
Does anyone see a problem with mounting an autopilot pitch servo control rod to the main elevator pushrod by using the hardware supplied for the mechanical pitch trim, i.e., a collar clamped to the main pushrod to which the pitch servo pushrod rod end bearing is attached?
Related question -- I vaguely recall that the STEC intsallation calls for brackets to be pop-riveted to the main elevator pushrod, and the rod end bearing is attached to those brackets. Is this recollection correct and, if so, does anyone have part number information so I can order up a set from STEC?
Related question -- has anyone who uses the mechanical trim system had the collar slip at all?
- Rob Wolf