Wings warp for birdlike agility.

Taking cues from seagulls, a bird-size prototype aircraft morphs its wings to navigate cluttered environments. The ability to shift its wings between an M shape for cruising and landing and a W shape for dives and turns bodes well for tasks in tight spots, from tracking wildlife in canyons to spying on an urban enemy, says Mujahid Abdulrahim of the University of Florida in Gainesville. By twisting its wings, the half-kilogram electric flyer can maneuver swiftly, executing three rolls a second, Abdulrahim notes. He and his colleagues made the prototype, in line with a trend toward the morphing of even full-scale aircraft (SN: 12/06/03, p. 359), by stretching plastic over a carbon-composite frame. They plan to share details of the aircraft next month in Albuquerque at a conference on unmanned aerial vehicles.