Ultra-Long-Endurance Progress

Ultra-Long-Endurance Progress: It's proving a long wait, given they are supposed to be "rapid" programs, but Boeing has begun taxi tests of its private-venture Phantom Eye hydrogen-fueled high-altitude, long-endurance UAV, while Mav6 has attached the payload/control car to its M1400 surveillance airship. Both are aimed at providing endurance measured in days, not hours.

Pictures: Mav6

Planned for deployment to Afghanistan and designed to stay aloft at 20,000 ft. for up to nine days, the M1400 is being built for the US Air Force's Blue Devil 2 program. It's hard to tell the sheer scale of the 370 ft.-long helium airship from the picture above, so below is a view from the top, showing the recently installed maneuvering valves.

The M1400 is powered by three Thielert turbo-diesels. Phantom Eye, meanwhile, has a pair of Ford truck engines modified to run on hydrogen and triple-turbocharged to operate at high altitude. The 150 ft.-span demonstrator is designed to stay aloft at 65,000 ft. for four days, as a precursor to a 10-day-endurance UAV. I'm sure it will fly well, but the Phantom Eye looks a little ungainly on the ground at Edwards AFB, on its take-off trolley AFB, taxiing (video here).

Photo: Boeing Phantom Works