The A160T Hummingbird, an unmanned helicopter from Boeing, recently set a flight endurance record when it stayed aloft for 12.1 hr.
It was carrying a 500-lb payload at 5,000 ft over California, and landed with 40% of its full fuel load still onboard.
The 35-ft-long Hummingbird has a 36-ft-diameter rotor and can climb to 30,000 ft, 10,000 ft higher than conventional helicopters can fly. It has a range of 2,500 miles and top speed of 140 knots. The helo is designed to carry a 300-lb payload, but has been flight tested with a 1,000-lb load. And according to Boeing, it can fly farther, hover longer (up to 20 hr), and operate more quietly than any other helicopter. Key to its performance are its rotors. The pilot who flies it remotely from a ground station, can vary the rpms to improve efficiency. The military is interested in the aircraft as a surveillance platform.