ArtW

The hinge didn't fail until the plane hit the asphalt runway. The hinge line was not sealed. That is an interesting wrinkle to this problem. The instructions do not mention sealing the hinge line. I have done it on some planes but not on all. I think, the issue is the "balance" surfaces on the elevator. The "balanced" elevator tabs must place to high torsional load on the elevator and horizontal stabilizer. The elevator starts to oscillate and has a resonance frequency that is too low. On the first flight the elevator fractured. On the second flight the horizontal stabilizer fractured. The design of the elevator and horizontal stabilizer is too light to prevent flutter, oscillation, and immediate fracture. I was stunned that there was absolutely no warning of flutter. The elevator simply fluttered and immediately failed. The entire failure took less than a second. Moreover, the plane was at extremely low speed. Control surface flutter can be a problem at high speed and is part of the reason for a Vne in full size aircraft. In this aircraft, the Vne is less than 10 mph. I think it just turned into the wind, fluttered, and failed.