Many years ago a now long departed older friend asked me to do the maiden on his just completed Pilot Pacemaker old timer style plane. He was one of the best builders around, but not the best mechanically when it came to setup. I had flown many of his planes without incident, so I took the box and pushed the thorttle stick forward.

When the plane got up to speed and altitude, the sound of flutter was heard and we could SEE the elevator flapping like a flag so fast it looked like a humming bird wing! I immediately throttled back and was able to land, although had to hold almost full DOWN elevator to do it, as pieces of balsa and covering were flying out the back of the plane.

The Csuse: Readily apparent, he had connected the elevator with a 4 - 5" piece of unuspported inner Nyrod instead of using metal pushrod after the Nyrod exited the outer tube as it exited the fusealge.

Damage: Horizontal stab rear (main) spar broken on both sides; most covering on horizontal stab shredded or missing; elevator horn hanging by one screw.

One could deflect the elevator almost 90 degrees down by pushing it with a finger. The inner Nyrod of course just bent like a soda straw.

Moral: Always test stiffness of your control linkages. ALL flutter is caused by aerodynamics, but can usually be prevented with proper control linkages.

littlera