I recently had a mishap witch resulted in some minor damage to my plane but more importantly, taught me a valuable lesson in setting up a plane for 3D flight. I am making this post to hopefully prevent someone else from repeating my errors .

The picture below is of the stab and elevators from my prized plane The stab failure was a result of a violent elevator flutter.



I assembled the ARF and setup the control horns based on the simple theory of shortening the horns will allow for increased throws, which at the time seemed like a no brainer for a 3D plane. The gaps were sealed and the servos used were the recommended servos for torque ratings but were not metal gear servos as recommended by the manufacturer. The servos that I was using I had purchased off EBAY and never opened the cases to inspect the gear trains. I basically set myself up for failure and did not realize it. I setup the plane with a very poor mechanical linkage setup and added to the problem by using servos that may have been questionable.

On the maiden flight, flying at half throttle, the left elevator started to flutter very violently, it took only a few seconds for the entire stab to blow apart and separate from the fuse. The pilot that was maidening the plane was able to land the plane inverted with minimal damage. The flutter and subsequent failure happened so fast the pilot did not have a chance to cut throttle. When we recovered the plane, many of the pilots at the field (myself included) felt the failure was attributed to a poor design (weak) stab.

I sent the above picture to the manufacturer for help in determining the problem. He took only a few seconds to tell me the setup of the control horns most likely contributed to the flutter and subsequent failure of the stab. Basically, in a very nice way, he told me I had screwed up and this was not a faulty plane He was nice enough to send replacement parts (stab, elevators and canopy).

With the replacement parts in hand, I reassembled the new stab and elevators with a the control horns as far as possible from the surface for maximum mechanical advantage (based on the manufacturers recommendation). The servos that were in the plane were removed and repaired (converted to metal geared) and reinstalled.

The subsequent flights were flown without any flutter which confirmed the manufacturers position that I was a dummy in setting up the plane.

In learning about mechanical linkage setups I found a great article on the Horizon Website which goes through and explains what I failed to do. The link for the article is here: [link]http://horizon.hobbyshopnow.com/ProdInfo/PagesAUX/1192-ART.asp[/link]

Hopefully, the above information might help someone from repeating my mistakes