First Fuel-Cell Manned Aircraft

In February and March 2008 The Boeing Company successfully performed flight tests of the first manned fuel-cell airplane in aviation history. The fuel-cell demonstrator airplane is a modified two-seater motor glider equipped with a hybrid power source powering an electric motor that drives a variable-pitch propeller. The hybrid power source comprises a proton exchange membrane fuel cell, the main power source, and a Li-ion battery that assists the fuel cell only during takeoff and climb, when the maximum power is demanded. The fuel-cell demonstrator airplane successfully completed four test flights. The airplane took off and climbed at 100 km/h, up to 1066.8 m (3500 ft) above sea level, with full power from the Li-ion batteries and the fuel-cell system. Once the cruise altitude was reached, the pilot disconnected the batteries. The altitude profile of the flight mission, logged in an International Civil Aviation Organization certified global positioning system, proved that the airplane maintained altitude. This demonstrated the first manned straight and level flight with only fuel-cell power. The fuel-cell demonstrator airplane generates water vapor as the only exhaust product and seems considerably quieter than the conventional airplane. This paper gives a brief description of the fuel-cell demonstrator aircraft's main subsystems, bench, ground, and flight test results, as well as the main challenges encountered while designing, building, and testing this prototype and the lessons learned for the implementation of fuel cells in aviation.