I made a small electric biplane recently. All from 0.505 blue insulating styrofoam. The Pitts Special was the outline inspiration. The span is 30", constant chord of 5", approx area of 295 sq in. The plane weighs 16 oz with rudder, elevator, ailerons, ESC. I only put ailerons on the top wing. Intended to put them on the bottom wing but the constant removal of the bottom wing led me to put them on the top wing, which is permanently attachec. After flying the plane I plan to put ailerons on both the top & bottom. The roll rate wasnt good. The blue foam is reinforced with 2" wide bi-directional fiberglass tape & covered with Econocote. Really light & strong

Now, the point of the post. I made the wings with different airfoils. The top wing is barely semi-symmetric, a raised-LE flat-bottom might be the way to label it. The degree of curvature is about 25% that of the top surface. The top wing has Pitts looking sweep and about .75" dihedral on each tip.

The lower wing is almost fully symmetric. No sweep, no dihedral.

My feeling was the lift characteristics were linear mathematically and the characteristics of both airfoils would be available to some degree. (They would add up, so to speak, much like the properties of oil in a multi-grade variety ... or wave phenomena, etc.) I wanted a slightly positively stable plane that wouldnt croak upside down.

The CG seemed happy about mid-way on the upper wing, which was staggered 50%. Decalage (sp?) was eyeballed to be 0* lower, -1* upper (very close to 0.5, enough to see it was slightly lower AA than the lower wing.

As for flying ... it barely flew on a 3:1 280 speed, 8 cells. It soared on a slope really well with no power. With a 4:1 speed 300, 8 cel, 8x6 prop it really flew well. When the speed dropped, the tip stalls were meaty. It was good that the recovery was pretty fast...

Anyway, I lost all power about 50' up and shattered the fuselage. (read homemade battery packs & worn out connector leads :O ) It was not covered at all. I plan to replace it with a 1" wide, near profile fuselage.

Does the idea of two different airfoil profiles make any sense? Before I rebuild the fuse, I want to know if I should also make another wing. If I do so, I will have both very close to full symmetry.

Derek