Fuel-cell flier

This article briefly describes a new electric high-altitude drone aircraft The Global Observer is intended to stay up for 7-10 days carrying up to 1,000 pounds weight of payload at 65,000 feet, operating as a fixed, near-space satellite for reconnaissance or communications relay. It is powered by fuel cells driven by liquid hydrogen. This fuel presents weight problems as it needs a larger tank than a hydrocarbon fuel, although it provides more energy per pound. The Global Observer's design features a central fuselage tank and a tail, with a bracing wire from the bottom of the fuselage to the half-span wing joint. The eight electric motors are spread along the wing, which will have a span of about 250 feet. Currently only a 50-foot-span prototype has been built, which has made short flights. (A)