Originally Posted by SaR
Sorry to hear of the mishap, Ed. What structural part failed?
Well, after a few cold ones, I finally got around to stripping the parts out of the A-4. I am happy to report that all of the servos survived (I had to replace the servo gears in all servos but they work fine now), the fan and motor survived. The ESC is broken but it will go back to Castle for repair. The retracts and retract valve also survived but the receiver and the Life flight pack batteries did not make it.
I asked the NTSB to please assist with the accident investigation
and with their help I have identified the cause of the crash. In disassembling the remains I found the left aileron had a clevis and parts of the pushrod still attached and the aileron had the other parts of the pushrod. Sounds simple but I was missing one important piece of the pushrod. Let me explain. For many years I have used carbon tube and the threaded titanium ends from Central Hobbies ( http://www.centralhobbies.com/contro...e/pushrod3.htm
) with wonderful success. However in looking at the plane I found that the threaded titanium ends had very little glue on them. What I did not find was he carbon tube that was supposed to connect the front and rear clevis'. This was clearly my fault and here is what the NTSB had to say.
" The inflight flutter and subsequent crash of the "giant foam A-4" was simply the result of a manufacturing oversight on the part of the builder. The aircraft was not at fault nor were the servos, receiver, motor/fan or ESC. Assignment of full blame for the crash is attributed to the builder, Mr. Ed
Here is what I believe happened. During the flight as the speed increased the little glue or lack of glue allowed the front and rear portions of the left aileron pushrod to separate which in turn caused the aileron to flutter and depart the aircraft. The subsequent flutter caused the other servos to fail. This in turn made the plane a very poorly flying free flight and the pilot was left to watch the impact.
Stop trying to make me feel bad because I do not have a big A-4 to fly.