bentwings

The Big Apple was the second generation of the twin .40s. It was very similar but had a tapered leading edge and straight trailing edge. I'm not sure exactly why but I know from my own experience with a number of pattern planes the straight trailing edge rolled much better, and snapped nicer. I actually have considered building a giant scale version of the BA with DLE 55 rear exhaust motors and tuned pipes....ever the hotrodder. 110-120" wing. I probably would build a couple of different span outer wing panels to try.

I never did get to build the BA. I had all the parts cut out and two K&B 7.5 ducted fan motors with pipes and we moved. My engineering career was getting a jump start and I had to concentrate on it. At some point I sold it as a builder kit. I do have plans some place but not in CAD. I think it would have had all the M 80 good points plus some others. I had planned on full gear doors and longer gear legs.

one issue the M80 had was the nose gear leg was too springy. I made a number of them but never really fixed it. The 7.5's liked a bit larger prop with more pitch. These were hard to get and rather expensive in the day. I often used a dozen or more props and a pair of glow plugs per flight. It was funny about fuel. A gallon of glow fuel lasted many guys a couple weeks. I could go through a couple gallons of 30% a day. The field was only a couple blocks away so I flew several days a week plus Sat and Sun weather permitting. I was one of the few that had a spare battery pack as well as a quick charger. Somewhere I have a single picture of me and my oldest son at a big meet. The M80 is partly covered as it was raining and I was getting ready to fly a repaired DB. As I recall it was a challenge to see who was the hardest core flyer. My son says we won but I don't remember.

i don't think you will have balance problems. I'd be more concerned about weight. As with most models the heavier they get relative to wing area the faster they land. Flaps again. Oh yes please don't use flapsrons. On our warbirds we use a little up aileron plus washout. This prevents early tip stall when landing. As your plane gets heavier using flaps it will land Corsair style....think carrier landing.