Hi,

I have had a few problems with my Synergy 90 3D lately regarding Tail Flutter...

I completed my Synergy that I brought back from Germany a few weeks ago, On the first test flight I had a serious case of tail flutter when flying straight and level at just over half throttle (OS 91 FX) I slowed down immediatly but one elevator clevis came off and the left elevator settled in the full down position.. I had to switch to full rates to get enough elevator to keep it from flying straight into the dirt, I managed to put it down in the next paddock but unfortunatly the long grass ripped the undercarriage clean out. (I had added tri stock reinforcing as Mark Novack suggested)
On closer inspection the brass pin in the elevator clevis fell out when the tail flutter occured. I had used all the supplied hardware except for the aileron linkages..

I repaired the dammaged undercarriage block and replaced the elevator clevises with du-bro locking clevises.
Next flight had a similar problem. After flying aroung a few circuits at low throttle I decided to push the stick foward to about half throttle, as soon as I did this the tail started fluttering violently and after a quick change of underpants I managed to land safely without damage. I noticed the violent shaking had broken one of my tail struts I had made from aluminium airfoil tube. It was back to the drawing board...

I have since replaced ALL the clevises and control horns with Du-Bro, and replaced both tail struts. I also straightened out a slight warp in one stabiliser side...

The next day I went out for another attempt - SUCCESS!! It flew much better with no sign of tail flutter even at full throttle.

I am still not really sure what the problem was, and if it is going to happen again when I am flying low inverted across the strip? I assume the light control horns were too flexible and allowed enough play in the linkages to cause the flutter...

Has anyone else had this problem?? The last thing I want is to loose my model because of something stupid like tail flutter...

Attached is a pic of my synergy right before the first flight (Note the long grass that is good for ripping wheels out..)