The demonstrator aircraft is a Dimona motor glider, built by Diamond Aircraft Industries of Austria.  It uses a PEM (proton exchange membrane) fuel cell/lithium-ion battery hybrid system to power an electric motor, which is coupled to a conventional propeller. The fuel cell provides all power for the cruise phase of flight, except during takeoff and climb. During that phase, when more power is required, the system draws on the lithium-ion batteries.  Its cruise speed will be approximately 100 kilometers per hour (62 miles per hour).

"While Boeing does not envision that fuel cells will provide primary power for future commercial passenger airplanes, demonstrations like this help pave the way for potentially using this technology in small manned and unmanned air vehicles," said Francisco Escarti, the managing director of BR&TE.

An example of other types of promising fuel cell technology is a solid-oxide fuel cell that could be applied to secondary power-generating systems, such as auxiliary power units. This technology could be mature enough in 10 to 15 years for potential use in commercial aviation, Boeing researchers believe.

BR&TE is part of the Boeing Phantom Works advanced R&D unit. Besides its colleagues in Boeing Commercial Airplanes, its European partners include companies in Austria, France, Germany, Spain, the United Kingdom and the United States.

The PEM fuel-cell system used on the flight demonstrator, for instance, was designed and built by Intelligent Energy, base in the U.K.  Madrid-based Aerlyper performed the airframe modifications, as well as the mounting and wiring of all components; SAFT France designed and assembled the auxiliary batteries and the backup battery; Air Liquide Spain performed the detailed design and assembly of the onboard fuel system and the refueling station; the Electronic Engineering Division of the Polytechnic University of Madrid (School of Industrial Engineering) collaborated in the design and construction of the power management and distribution box; post-integration bench testing is being conducted in a facility that belongs to the Polytechnic University of Madrid (INSIA); and SENASA (Spain) will provide a test pilot and facilities for flight tests.

Other suppliers for the demonstrator include UQM Technologies Inc. (U.S.), MT Propeller (Germany), Tecnicas Aeronauticas de Madrid (Spain), Ingenieria de Instrumentacion y Control (Spain), GORE (Germany), Indra (Spain) and Inventia (Spain).

Boeing says, the flight tests, which will take place in Spain, will demonstrate for the first time that a manned airplane can maintain a straight level flight with fuel cells as the only power source.  04-01-2007.