Howard Fink — My Paper Airplanes

January 12, 2013

C Wing airplane

Filed under: Uncategorized — @ 9:54 pm

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19960023622_1996039477.pdf is a 1995 paper in which a genetic algorithm was set to design an airplane wing of fixed lift and span, minimizing drag.  The result after 120 iterations was the C wing.

c_wing

c_wing_front

This uses a legal-size sheet of 16-pound paper. ( 8-1/2″ x 14″ or 216mm x 355.6mm and 60 grams per square meter).  The full sheet of paper is 4.6 grams, or about 4 grams for the completed airplane.  The rolled leading edge taped flat and folded is enough structure to keep the upper horizontal surface of the C wingtips relatively flat. The fold needs to be refreshed to remain horizontal.   This plane flies quite well, with a L/D of 6 or more.  No flutter when flying in circles or in glides.  The original Barnaby glider had a full wingtip fold instead of a winglet.  Who would have thought in 1908 a second fold would be a breakthrough in aerodynamics in 1995?

A small cut about a quarter of the way in on the initial folds that create the vertical wing panels allows the trailing edge of the wings more camber, which improves the L/D to 7.  In addition, this provides more adjustment of the wing loading, which must be equal in order to fly in circles and return at the same altitude.

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