I have/had a TT91 FS in a Great PLanes Big Stik. I flew the plane aroudn with authority and never let me down. I only pule the motor out when the exhaust manifold/pipe broke and the muffler came off. Luckily it was still on the ground preparing for the first flight of the day. I plan to order a replacement pipe and with return it to a plane soon after.

The Big Stik crashed about a month ago with a a YS 91-FZ.