I'm afraid I had exactly the same experience with mine, powered by an OS 91FX.

Mine, however, had the added excitement of one of the stabilizer sides breaking off on the first flight while flying level! Luckily, the other side still worked OK (I had dual elevator servos), and the break was clean enough not to flap around, making it possible to land.

So, having fixed that, I flew a few more times, but finally gave up due to the horrendous snapping which was making it too much like hard work to fly. I just couldn't trust it to come out of any sort of dive, at any speed, without flipping over onto her back.

I tried everything, including reducing the elevator movement to such a small amount that maximum throw was not enough to loop!! CG movement forwards and backwards, checking equal elevator movement, checking lateral balance, - the lot!

It looks good, and flies level pretty well, (big deal!) but that snap has made me move onto Extras and Edges.

-David C.