Re: LS1 midspan hinge repair
|
Vern,
toggle quoted message
Show quoted text
I do not have Q plans. From the discussion I surmise an Aluminum arm is bonded to the canard and it failed in fatigue between the hinge at the huge change in stiffness where it is bonded in. Stress follows stiffness change. I chimed in because I seem to remember an accident where this might have been a factor in a inflight elevator failure. I cannot remember details. Fatigue failures are insidious and sadly not considered in plastic airplanes not designed to last a half century. My 767 door springs had to demonstrate 200,000 cycles to qualify. How much testing did the Q Corp do on hinge arms? For your somewhat off topic question. Dragonfly has tip bearing, 2 mid span hinge arms 4130 steel bonded in and the elevator torque control tube is coaxial and plugs into the elevator hinge tube. Torque loads are transmitted through the Revised bonded in wood rib with a bellcrank and two bolts directly to the skin laminate. The Dragonfly elevator flutter issue was using -3 bolts to pin the aluminum hinge tube to the steel elevator control tube in the fuselage that was also pinned together with -3 bolts. The only thing between the hinge tube and elevator skin, 2 lb styrofoam. When things got shaking the bearing strength of the hinge tube was not enough to keep the holes from elongating allowing flutter. No one lost a fluttering elevator which at least took the hinge joints to limit loads. Regards, On Monday, May 9, 2022, 12:42 PM, Frankenbird Vern <smeshno1@...> wrote:
|
|
|