Sign in to follow this  
Followers 0

Trim systems for model C


3 posts in this topic

Posted

There appears to be no provision for pitch trim on the model C.  Using the flaperons for trim might work in cruise, where the q is high, as they can be used to effectively set the wing's moment contribution, but using them in the pattern at low speeds would have you trying to increase nose-up moment by further upwards flaperon deflection, which may not be possible.  You'd likely run out of trim capability.  At low speeds you would ostensibly want them deflected downward anyway to augment lift.  You can always slip if you want drag for a steeper descent.  At low speed, with them down you'd be way out of trim!  I figure I'll put a tab (bellcrank) on top of the elevator tube between the seats then connect it to a bungee or spring somewhere aft, the aft end of which connects to a large RC electric actuator.  This way, I'd be able to trim out the stick force for low - speed operations, yet still be able to command pitch changes with the stick.  The remaining question is what spring rate would be appropriate.  Guess I'll have to measure stick moment and play with it.  Any thoughts on alternative approaches?  I'm not too keen on tabbing the elevator, although the electric actuator could be placed out there ahead of the tab, I suppose.  Too ugly!  Then there's the perturbation to mass balance...

Share this post


Link to post
Share on other sites

Posted

Kitfox 5 used a heavy electric servo to move the leading edge of the Horizontal Stabilizer for trim much like the Piper had a hand crank and chain - Your Avids and earlier Kitfoxes could be modified to use it.  I have an unused one I would take my original $300 for with plan drawings for it in manual.  I see these listed in Spruce now for about $700-$800.  EDMO

Share this post


Link to post
Share on other sites

Posted

I always liked that model A Ford window-crank trim on the ceiling of my old tri-pacer. Like opening & closing a sunroof!

Bandit showed a pic of a ridiculously elegant trim setup in another thread.  I think that' the ticket!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0