This Profile scale model of an Aeronca 7Ac Champ was built from plans by R. D. Hawes in the Flying Aces Club Newsletter (Jan/Feb 2009 No. 245). It is light, with an airframe weight of 11 grams and rubber motor weight of 1.4 grams.  The motor is an 8.5 inch loop of 1/8 inch wide FAI Tan rubber, about the length from the propeller hook to the rear hook. I tried narrower and longer motors, but did not get climb. The propeller is a 6 inch diameter one from North Pacific, lightened by sanding. Winding to 750 turns, I've gotten 50 second flights in Memorial Hall. It is a docile flyer, with cubic wing loading just above 2 ounces per cubic foot.