BMatthews

Ive got one of these engines that I've never run yet. It's truly a real cutie.

One of the English mags had a couple of designs for them a few years back. The big thing is to keep the model light and larger so that it flies on the wing and not the prop. Old timer cabin or shoulder wing designs in the 50 to 60 inch size range would be perfect trainers but may be a little lazy for you depending on what you want.

For something moderatley aerobatic I agree that many of Randy Randolph's designs would be just right. Pick the wood to keep them light and consider shortening the nose by about 1/2 inch to compensate for the greater weight compared to the usual 15 sized 2 strokes that he liked to use.

In any event don't plan on going over about 2 1/2 lbs if you want to have any sort of climb ability. 2 lbs would be lovely but it'll take some serious wood selection and the right design to do that.

I'd suggest a 3D type construction but that would be so far out of the character for this engine that it would be silly.

I'm planning on using mine in something WW1'ish with about 500 to 550 sq inches and built up like an old timer stick and tissue model. There's been a lot of Speed 400 electric biplanes offered in the English mags in the past couple of years. They all have around a 36 inch span and run through a photocopier to enlarge them up to about a 44 inch span would make them perfect for the FS20. Just resist the urge to beef them up. Stick with the wood sizes of the smaller version with just enough adaptation around the firewall for the engine and it would build up to about that magic 2 or 2 1/4 lb mark with small radio gear.