Before Orville and Wilbur Wright, many early airplane designs looked like giant birds. Some even had flapping wings. Now, Richard Dryden, a biology lecturer at England's University of Plymouth, has returned to nature for inspiration--but for a new type of sail. The concept has just won a $70,000 grant from Britain's National Endowment for Science, Technology & the Arts. Dryden plans to spend next year working full-time on his wing sail, which looks more like the wing of a bat than that of a bird.
Dryden believes the bat-wing sail may prove useful for all manner of watercraft, from sailboards to oil tankers that exploit wind power to reduce fuel consumption. His system's key feature is that the mast and sail automatically adapt to changing winds. The mast has joints, like the bones of a wing. In strong winds, the joints bend to reduce the sail's size. This trimming of the sail lowers its "center of effort"--the area where most of the wind's force is concentrated--to avoid excess pressure at the top, which can shred the sail or capsize the boat.