Freak Aerodynamics

Lilly is doing a how-to demonstration in school tomorrow. Technically, it's a how-to about origami, but in fact it's about making a good paper airplane. She made one this evening, a nice construction with a number of fancy folds under the wing, and threw it at the ceiling fan in the room off the kitchen. The fan was rotating. Her paper airplane slid onto one of the blades of the fan, and stayed there for a few minutes as it continued to rotate.

One of the folds was apparently exactly the right size to catch the blade, and it entered the fan's airspace at exactly the right angle, at exactly the right moment. I was astonished. I told Lilly she could throw that airplane at the fan every day for a year, maybe several times a day, and probably not have the same outcome again. Unless there's something I don't know about the aerodynamic interaction of ceiling fans and paper airplanes.

My paper airplanes were never very sophisticated. Many imaginary test pilots died in them. As for origami proper, the father of a friend of mine in elementary school was pretty good at it, the only person I ever met before I lived in Japan who had the knack. I never put the necessary effort into mastering origami myself, though I'm good enough at origami boulders -- but who isn't?