Andrzej Jeziorski/Munich
DAIMLER-BENZ Aerospace (DASA) is planning to turn a Dornier 328 turboprop into a hydrogen-powered testbed, with a view to possible serial production.
The test aircraft is scheduled to be flown in late 1998, and the flight could lead to production of an operational, hydrogen-powered turboprop by around 2005, says DASA head of alternative fuels, Hans-Wilhelm Pohl. The aircraft will not emit carbon dioxide - only water vapour and a small amount of nitrogen oxides.
The 328 variant will be powered by Pratt & Whitney Canada engines with specially-developed combustion chambers designed to optimise the burning of the hydrogen/oxygen mix and minimise nitrogen oxide (Nox) emissions. They will use technology developed by P&WC, AlliedSignal, the German Aerospace Research Establishment and DASA Airbus.
The extra fuel volume necessary will be provided in the form of underwing fuel tanks outboard of the aircraft's engines - liquid -hydrogen fuel requires four times the storage volume of kerosene. Pohl predicts that while the engines will generate the same power as conventionally fuelled turboprops, the increased drag of the fuel tanks will reduce the aircraft's usual 335kt (620km/h) maximum speed by about 15kt.
Elements of the insulated fuel system will be manufactured by Russia's Tupolev, with which DASA has a long-standing partnership on a projected Cryoplane: a planned hydrogen-powered jet transport based on an Airbus airliner, most probably the A310. The companies, along with Russian engine producer TRUD (formerly Kuznetsov) have co-operated in this field since 1989.
Pohl predicts that a prototype of the Airbus-based aircraft could appear in the second half of the next decade, possibly leading to serial production in around 2010-15.
A natural-gas powered variant of the cryonic-fuelled 328, with a different combustion-chamber design, could also be manufactured for use in the former Soviet Union.
DASA Airbus is now conducting experiments with large cross-section combustion chambers, while tests on a new fuel-nozzle design are to begin soon. Pohl says that the 328 testbed's engines will generate only 5% of the Nox emissions of comparable conventional engines.
The hydrogen fuel will be provided under the Euro-Quebec Hydro-Hydrogen Pilot Project, begun in the 1980s.
Here, excess hydroelectricity would be used to produce hydrogen, which would then be transported by ship to Europe for use as fuel.
Source: Flight International
