Gliding high with servos

Flocks of unmanned paragliders steer themselves through dangerous missions using innovative servoactuators. The Onyx platform in flight, here carrying an iRobot surveillance bot payload. The Onyx retracts and extends parafoil steering lines to maneuver its parafoil via capstans mounted to custom dc motors via planetary gearheads. Servos also control parafoil angle-of-attack for long or short glides. Developed for Darpa, the Leapp paragliders are slow-flying, long-endurance UAVs for surveillance and delivering payloads. The MicroLeapp version (below) is small enough to be carried in a backpack. Its big brother can carry up to a 250-lb payload and is powered by a turbo diesel engine. For a ground launch, soldiers unfurl the paraglider wing behind the vehicle. Takeoff is in 100 ft or less and need not be from a paved runway. It may sound like a low-tech way of flying military missions. But guided-parachute systems developed by , Brooklyn, N.Y., are anything but. The basic idea: Launch a small propeller-powered platform attached to a high-tech parafoil. Then give the platform enough smarts to fly itself, follow a flight plan, and manage fuel in such a way that it can hang around in the air for days on end. The Long Endurance Autonomous Powered Paraglider, or Leapp, UAV is designed for special operations intelligence, surveillance, and reconnaissance. It can operate autonomously or be piloted by remote control via a portable base station. The MicroLeapp version is light enough to go in a backpack, flies for up to 8 hr, and can carry a 50-lb payload. It gets power from a gas engine not much different from those in model airplanes. A bigger version of the Leapp UAV carries a turbo and supercharged diesel engine. It is designed to fly for up to 55 hr at greater than 35,000 ft using the largest elliptical paraglider