Hi,

Has anyone out there experienced horizontal stabiliser flutter on the Exelleron 50 airplane?

Yesterday I experienced horizontal stabiliser flutter, and I still have the aircraft to tell the tale. This occurred on flight number six.

However, the story goes back to last week, when I did the post-flight inspection of the Excelleron after 3 flights. I discovered that the horizontal stab failed (broke) cleanly along the centre-line, and the only thing holding it in was the epoxied attachment to the fuselage sides. I noted at the time that the tail seemed a bit flimsy and the first three flights were accompanied by a buzzing sound from the airframe. However I repaired this and proof loaded it to a 12g tail balance load. On the next flight I experienced flutter of the tail whilst at about 30 ft and about 100km/hr (occurred right in front of me). I managed to recover the aircraft intact (by miracle) to do an inspection. The forward and aft spars had broken symmetrically (both LH and RH side) and snapped the elevator pushrod out of the servo arm. I have attached some photos of the horizontal stab with the covering cut away showing this spar damage.

The elevator gaps were sealed and the control linkages had very little or no backlash or slop.

Regards

Waz

PS. I have rebuilt the tail, and after a dozen flights I have yet to experience flutter