UAVs

Aerovironment is claiming the world’s first demonstration of a liquid hydrogen fuel-cell-powered high-altitude long-endurance unmanned air vehicle. The eight-engined Global Observer testbed is a one-third-scale version of a proposed 45-61m (150-200ft)-wingspan hybrid fuel-cell- and solar-powered UAV Aerovironment hopes to develop for NASA’s planned ultra-long-endurance high-altitude UAV research programme.

The name Global Observer is derived from NASA’s own proposed Global Observer “eternal aircraft” demonstration planned for 2014 as a successor to its environmental research aircraft and sensor technology programme. NASA plans an interim long-endurance Observer UAV demonstration in 2009-10, but this depends on funding.

Aerovironment’s self-funded Global Observer design draws on lessons learned from the loss of the company’s Helios flying wing, hybrid fuel-cell- and solar-powered UAV over Hawaii in June 2003, including shifting the fuel cells from wing pylon mounts to a central fuselage to avoid point loading problems.

The sub-scale Global Observer prototype has a wing span of 15.2m and carries eight electric motors. The full-scale version could fly for more than a week carrying a payload of 4,530kg (10,000lb).