Elevator Balancing
NOTE: This is no substitute for using your builder's manual! Always build according to the manual.
Some Critical Dimensions
Elevator Deflection
Full Up 24 - 26 degrees Full Down 28 degrees min. (Be sure that you are getting full 26 degree down elevator and, at least, 21 degrees up elevator.)
Gap between Canard trailing edge and Elevator
Elevator Neutral Position 0.050” Elevator Full Down 0.200”You will note that in the assembly of the elevator - canard hinges, (Figure 14-2) there are 2 washers, one on each side of the elevator mounted hinge. The hinge arm, mounted to the canard, connects to the hinge on the side where the bushing protrudes from the hinge. When installing the assembly, tighten the hinge screw until it is snug, then back it off one-half turn. Lock it in place with the appropriate locknut. It helps to lubricate the screw with some white grease. Once assembled, check the system for binding and full travel.
Have the elevators installed loosely on the canard for balancing. Block the canard up on a flat table as you did to check you elevator travel.
Without paint, the elevators should hang slightly nose down. Ideally, with the final finish applied, the elevators should balance bottom side level. A bit nose down is acceptable.
The reason for proper balancing is to prevent flutter. Flutter can occur at high speeds and is aggravated by turbulence. Thus, to achieve the highest safe Vne (Never exceed speed ), all control surfaces must conform to the above balancing criteria.