Troy:

A couple notes.

I've not used the Spring-Airs, but whatever retracts you use mount the nose gear mechanism as low on F1 as you can and still have everything come up inside. The limit on nose gear length is the front wing mount, can't cut it away.

Another possibility is moving F1 forward in the fuselage, but that would have to be planned ahead, making the sides, top, and filler sheets longer to match.This could also aggravate the nose heavy tendency, so if you do it do it carefully.

When you fit the mains in the wing you can put the wheel wells right against the root rib. This gives you the longest possible main gear length. To decide how long you actually want them, by this time you should have the nose gear mounting to the point you know how long you can make it, lay it out on the side view plan, then using a yardstick you can see not only how long the mains want to be, you can also check prop clearance.

The first paragraph in the quote Tim attached was talking about the wing fillets. They are important, the fuselage is not strong enough at the rear of the wing seat without the fillets, or some other reinforcement. I also like to fill the space between the top of the wing and the threaded mounting block too, if you do this you might be OK without the fillets.

As a final note, the plane was designed for 0.40 two strokes running at a high rpm, with the smaller props they used. Your 0.52 four strokes won't be happy at high rpm, I'm afraid you'll find you have to use three blade props whether you want to or not. Or use two stroke engines. Your OS engines should run nicely with Zinger 10x6 three blade props. And Du-Bro has nice spinners to fit them. Or Tru-Turn, at $70 the pair.

Keep us informed of your progress, always happy to see another Duellist.

For your next project, I expect to see the 2/60 (twin 60 engines) released this fall, with the smaller version for 0.15 engines soon after.

Bill.