Deconstructing Flight

An article in yesterday's Washington Post highlights some interesting research into the mechanics of flight. It compares the flight styles of both insects and birds, primarily ones that can hover like hummingbirds and hawk moths. One project used 1,000 fps video to break down a turning motion while in flight.

The answer turned out to be surprisingly simple. First, the animal initiates the turn with asymmetrical flapping.

Then, rather than stopping the turn with a reverse asymmetrical flapping, the animal switches to regular symmetrical flapping. At that point, natural aerodynamics kick in.

"There's a simple rule for slowing back down: It's going back to being symmetric. You don't have to try anything special," said Hedrick. "What we have here is a shortcut rule for stability."

Hedrick and his colleagues universalized the principle when they noticed similarity between the flapping motions of hummingbirds and fruit flies. They studied nine types of creatures, including a hummingbird, a cockatoo, a bat and four species of insects, and all used FCT.

FCT is the acronym for "flapping counter-torque."

I think that the flight mechanics are interesting on their own, but there is some backing for this research coming from military sources:

The military, Willis said, "would love it if they could robotically control a moth and have it fly into a window with a camera on its back."

Apparently there may be some other applications for rescue operations, perhaps involving some other kinds of sensors rather than cameras. All that is a long way off, however, because of the difficulty in engineering structures that are as strong and flexible as animal wings. So for the moment we just have some interesting research.