Electric nose wheel could reduce aircraft emissions

Commercial aircraft could cut their on-ground emissions by one quarter with a new hydrogen fuel-cell propulsion system, according to its creators.

Researchers at the German Aerospace Centre (DLR) supported by Airbus and Lufthansa have developed an electric nose wheel that could allow aircraft to move around airports without using their main engines.

For short-haul aircraft that often take off and land seven times a day, this could save between 200 and 400 litres of kerosene per day while reducing noise by around 95 per cent, without the use of towing vehicles.

The nose wheel drive system has already undergone successful tests in the laboratory, and comprises two highly efficient electric motors that are built into the rims of the aircraft’s nose wheel.
The nose wheel drive system has already undergone successful tests in the laboratory, and comprises two highly efficient electric motors that are built into the rims of the aircraft’s nose wheel

The system, designed for an Airbus A320, uses a low-temperature polymer electrolyte fuel cell driven by hydrogen and can provide ground propulsion for an aircraft weighing up to 70 tons.

It allows the pilot to turn off the main engines one minute after landing and not turn them on until three to five minutes before take-off, in order to heat them up. This means the engines could be used 1,200 hours less per year.

‘The weight of the propulsion system has to be as low as possible,’ DLR project manager Josef Kallo told The Engineer. ‘If you have a lot of weight in the nose wheel the hydraulics have to be changed.

‘It has to be very compact to fit into the rim of the nose wheel and has to have very high torque. Just to get to 3–5kph you have to work against something like 5,000–7,00NM.’

The DLR team took inspiration from electric cars to solve the power mass problem and looked to stationary applications and trains for the answer to the torque issue.

Kallo could not reveal how much hydrogen it consumed but said for a short-haul aircraft it would need refuelling every one or two days.

The team plan to trial the system in a Lufthansa test vehicle in Hamburg in April 2011.

They are also developing a fuel-cell unit for auxiliary power for the aircraft’s climate control and other electrical systems, which is currently provided by a turbine in the aircraft’s tail.