Mine is finally ready to fly, with OS .91FX and a cut down 14x7 3 blade prop. Needed a bit of lead in the nose to balance at 10". I just mounted a plastic servo box and filled it with shot until balance was right, then added epoxy. I ran the engine and this this is going to scream. I am sure you could exceed the airframe limits fairly easy with this engine. It is very light though. Maiden sunday maybe. Bob