This will be my second plane.Up to what size engine can you put on this plane before before you have to start worrying about structural issues. In other words could you put a Saito 100 on it without worrying about tearing the plane apart?Thanks for any and all help.

Mine flew beautifully on an OS 71FS. I wanted that engine for another airplane so I have a Saito 91 in it now; it has good vertical but not outstanding, so I think the 100 would be great! However, I would pin the firewall (drill in toothpicks or bamboo swewers), and reinforce all of the joints. This is a very light weight airframe for such a large airplane, so you will want to be careful with your throttle management. Oh yes, don't expect it to go fast. It is at its best flying slow, and doing outrageous airobatics. My club oohs and aahs at what it will do.

Yes, that big fat wing won't let you fly fast no matter how big a motor you hang up front. More power does give the plane an added dimension, though. Saito 100 will do just fine, and won't require too much reinforcements. I put a Magnum 1.20FS on mine and went nuts reinforcing the plane, mostly on the fuselage behind the wing, where I fully sheeted top and bottom with cross-grain 1/16" balsa.

With a Saito 100, you'll also be okay balance-wise. mine needed a lot of tailweight to balance that 31.5 Oz 4stroke. I hate lead, so I sheeted the horizontal stab and enlarged/reshaped the tail feathers. I also mounted 3 servos near the tail. All that and a HD Tatone tailwheel assy finally got the plane balanced at the factory recommended point, which is correct BTW despite being much farther back than the traditional 33% chord. Mine came out a little heavy at 10lbs RTF, so now I'm gonna swap in a TT Pro120RP.

I wouldn't recommend all these mods, though. I pretty much turned it into the WM Fun World 3D, which wasn't available yet when I bought the Super Stunt 60. If I buy an SS60 again, I'd probably just do a taildragger conversion and keep it light.

Good luck and enjoy the plane. It was, and continues to be, the best $199 I've spent since I got back to RC a couple of years ago.

A follow-up on my previous post: I moved up from a 12x8 on the Saito 91 to a 13x6-10 and now have unlimited vertical, tail slides, harriers and more fun than a barrel of monkeys!