Nature Suggests Different Ways To Fly
A jellyfish and an owl have inspired researchers recently with new insights about how to fly more efficiently and with less noise. The oscillating movement used by jellyfish underwater can translate into aerial capabilities, as proven by a tiny hovercraft built by Leif Ristroph, a mathematician at New York University. The tiny 3-inch-wide prototype, which he demonstrated at the recent meeting of the American Physical Society, in Pittsburgh, hovers using four small petal-like wings that open and close. The machine "achieves self-righting flight using flapping wings alone, without relying on additional aerodynamic surfaces and without feedback control," Jaworski said. At the same meeting, engineer Justin Jaworski of Lehigh University said the mechanics of owl wings may help design quieter airplanes.
Jaworski's research is exploring how the structure of the various parts of an owl's wings helps it to fly so quietly. "Owls possess no fewer than three distinct physical attributes that are thought to contribute to their silent flight capability: a comb of stiff feathers along the leading edge of the wing; a flexible fringe at the trailing edge of the wing; and a soft, downy material distributed on the top of the wing," he said. Jaworski said the velvety down may have an unusual sound-absorbing mechanism that hasn't been studied before. The research could help determine how the use of flexible fibers could help eliminate noise from airplane surfaces and wind turbines.