Advanced Technology Products (ATP) is planning to develop and fly an electrically powered DynAero Lafayette III light aircraft early in 2004 and aims to demonstrate fuel cell-powered flight in January 2005. The timetable means that the fuel cell/battery hybrid E-Plane will fly at about the same time as Boeing Madrid's Diamond HK36 motorised glider demonstrator, for which ATP is providing the electric motor and batteries (Flight International, 22-29 July).

Massachusetts-based ATP is embarking on Phase II of its three-phase development programme, having been awarded $400,000 by NASA and the US Foundation for Advancing Science and Technology Education.

The E-Plane will initially be powered by high-energy lithium batteries and a UQM Technologies DC motor, which will give the converted Lafayette a range of about 155km (85nm). For the second set of tests batteries will be used in conjunction with two 10kW fuel cells to boost take-off and climb performance. With the battery augmentation, the Lafayette is expected to require only a 60m (200ft) ground roll and boast a 2,500ft/min (12.7m/s) climb rate. At an altitude of about 3,000ft, with the batteries mostly expended, the fuel cells would provide all the required power to sustain flight for about 2.5h.

The third phase of tests will use more powerful 30kW fuel cells and eliminate battery power except for emergency reserve power.

The Lynntech Technologies fuel cells each weigh 21.7kg (47.8lb) and are based on Lynntech's cells developed for the NASA/AeroVironment Helios flying wing. Gaseous hydrogen is stored in two 350bar (5,000lb/in2) carbon filament-wound tanks.

ATP president and E-Plane project leader Jim Dunn says further developments in fuel cell technology could be incorporated in subsequent phases. "We've developed our own approach using ammonia and, in a fourth phase, we'll fly with ammonia as our base fuel," he says. Like the water-producing hydrogen cells, the nitrogen produced by the ammonia cells would be vented into the atmosphere.

Source: Flight International