Elevator Balancing Using Shock Cord

With regards to the trim, Many gliders do not have a control surface trim, instead they use a spring (or springs) to trim the aircraft. As my elevator is not balanced, I attached a length of shock cord (stretch bungy cord) to my top elevator cable and stretched it through the seat back to hold my elevator level with the horizontal stabilizer and tied it off (not adjustable). I hardly need to use my trim in flight to trim to the required attitude (NOTE: in sailing we use shock cord into cleats to assist in trimming some of the smaller sailing boats, this is where I got the idea)

16 Apr 2005 - I do have a trim control surface, which is not enough. At cruise the trim is almost fully forward, and I cannot trim the KR2 into a descent above 140kts, I have to push the stick forward. Therefore I think I require a little less tension in my bungy cord. These test were all done one up.

15 Jun 2005 - After doing some tests two up, I will make the shock cord adjustable as my control surface trim is insufficient.

Shock Cord coming through seat


Shock Cord running back and attaching to elevator cable


Shock Cord attaching to elevator cable


Shock Cord going through seat, reverse angle

I intend to use the adjustable idea on the right rudder cable to trim the aircraft during climb and cruise (on decent no rudder is required, on cruise only the slightest right rudder is required) The advantage of shock cord is that being stretchy you can override the trim with normal control inputs