power to maintain level flight. The fuel cell is powered by a high-pressure, hydrogen storage tank, located aft of the cockpit. The extra power required for take-off and climb is supplied by a bank of lithium-ion batteries located where the passenger would normally sit. The current state-of-the-art for fuel cells still results in a power-to-weight ratio far inferior to a modern internal combustion engine.  

It is expected that the Dimona, powered by this exotic multimillion dollar powerplant, will be able to fly a very limited mission consisting of take-off, climb to 3,000’, cruising 30 minutes or so, and returning for landing. Remember, though, that the point of the experiment is to move along the technology for commercial use, not to create a viable general aviation powerplant. I suspect that the rate of progress in fuel cells, driven by government and auto-industry money and interests, will result in power-to-weight ratios and acquisition costs acceptable for specialized applications, such as motorgliders, sometime in the next 10-15 years.   

THE BOTTOM LINE?
Look for fuel cells in the tail of your favorite Boeing airliner around 2020, in use as an APU, but probably not under the cowling of your favorite Cessna.

OK– SO WHAT’S THE ANSWER?
Here’s my take on the future. In the next ten years, we’ll see two things happen; the first is the adoption of a new standard, unleaded, mogas/avgas to be used in existing 100LL engines. (There is an outside chance that alcohol will be used as a fuel in some localities where there is the political will and local agriculture looking for a new market.) The second is the gradual introduction of new airplanes designed around turbo-diesels, most likely

The Boeing “Fuel Cell Demonstrator”, Diamond Dimona motorglider, in the Intelligent Energy integration lab located in the UK. The above photo depicts the fuel cell systems installed, featuring a UQM electric motor.

derived from mass-market automotive engines. In the next twenty years, we’ll see the introduction of fuel cells or hybrid powerplants, only for specialty applications in general aviation such as motorized gliders or experimental aircraft. The majority of the general aviation fleet will continue to fly with a high-octane, unleaded fuel, but fuel prices will increasingly drive pilots to convert to more fuel-efficient Jet A burning diesels. Time will tell, but I believe that the increasing real and political costs of crude oil will force us towards a more fuel-efficient future. Ready or not, here we come!                                                   ~Michael Friend