BMatthews

Moved from Aerodynamics to SPAD. The plastic benders here will have some more ideas on how to best build your design to be successful.

At that weight it will fly but not well. But more importantly I'd be worried about the wing folding up at the first bit of added G load from a turn or pulling out of even a shallow dive. It is far too thin to hold the sort of spar you need to be strong enough for the flight loads it'll see. You don't say what you made the wing from but by the looks of the graphics I'm guessing that it is corroplast sign board. The wing will not hold up to any flight loads you'll see with anything near that sort of weight. Even at a 1 lb takoff weight the wing would suffer from extreme bending and likely fold up and crash the model. The little stub of wood or whatever you used at the root isn't going to be anything like enough. Even if you ran such a strip for the full span it would not be enough. Even at a 2 lb weght the flight maneuvers will generate enough G load to fold that flat wing. It may not even survive the takeoff. A single layer of corroplast is just not structurally strong enough or rigid enough to use as an RC model wing of this size and shape.

Even with a regular airfoil 250 sq inches is not a lot of area. The takeoff, landing and stall speeds will all be quite high. It would also be suceptable to high speed stalls and snap rolls with the flat or thin airfoil and the high wing loading. If you were to redesign and build a wing with adequite strength you would still want to keep the weight down to more like 2 to 2.5 lbs at a maximum. Even then it would be a fast takeoff and landing speed. 250 sq inches is what I fly with using an .049 that weights 1.5 lbs. And that has a comfortable landing and takoff speed. Up to 2 lbs I would still find OK but not as much fun. But much over that and it becomes a "special" model that would seldome be flown for fun because keeping it within its flight parameters would become too much work for my tastes.

Now that we've pretty much ripped your dreams up I will say that it LOOKS nice for the material you are using. It's hard to make a model from corroplast that has good looks yet also works within the limitations of the material. If it were me I'd make the tip chord a little wider so that the wing area bumps up to 300 sq inches. And keep the "payload" down so the whole model weighs no more than 2 to 2.5 lbs then you would have something that would fly very well. But it sure as blazes will NOT be a trainer. Not even a second model. But as a third model and provided you're VERY capable at flying your second model which should be a fairly sporty handling type then you'll be ready to try something like your twin boomer. At 2 lbs it would fly with a lot more forgiveness than if it is heavier. At 2.5 lbs it'll take off and land at racer like speeds. At 3 lbs it'll be a handful and a half for landings and takeoffs. And in the air it'll begin to do nasty snaps out of turns and dive recoverys when you least expect it due to the wing loading. So do try to keep it under 2.5 lbs for best results.

You can use corroplast for the wing and still keep it fairly thin. By getting some thinner material and creasing the inside along a couple of corrugations you can fold the material back on itself and include a carbon fiber tube about 5/16 to 3/8 in diameter at the high point to act as a spar. Even better would be a stick of wood about 1/2 inch wide by 3/8 deep that tapers to 1/2 wide by 1/4 deep at the tip. Then glue flat carbon strips 1/2 winde by .035 thick to the top and bottom of that wood spar and then fold the corroplast over this spar. The wing will still be pretty thin but it'll now be both strong and rigid. You'll need to do separate wings with this method and then join them using a good solid method at the root. Also you'll want a really good way to bond the tail booms to the wing and the fuselage to the wing. But the folks here in the SPAD forum should be able to help you with that.

Good luck on the rebuild and I wish you success with the new and better version.