"The aircrafts own auxiliary power unit, or APU, provides the electrical power needed by the motor. The APU is actually a gas turbine/generator unit, generally located in the fuselage tail,"
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The plane's own wheels could be used during 'braking' to generate energy to be stored and resupplied to assist in Taxiing, Auxiliary power, etc... Thus, relieving some of the load needed by the APU.
Honeywell and Safran, a French aerospace company, said they will launch a joint venture to create an electric taxiing system for airplanes in a move that will save money, fuel and carbon emissions.
The companies said the electric taxiing system will use an airplane’s Auxiliary Power Unit (APU) generator to power motors in the main wheels without using primary engines while on the ground.
Today, airplanes use their main engines and taxiing eats up 4 percent of total fuel consumption. That percentage equates to 5 million tons of fuel used just to taxi.
Under the joint venture’s plan, the Honeywell-Safran system will be installed on new aircraft and retrofitted on existing planes starting in 2016. The two companies appear to be a good fit since Honeywell specializes in auxiliary power units and Safran makes landing gear systems.
Safran explained how the system works on its Web site:
From the technical standpoint, each powered wheel in the main landing gear is equipped with an electric motor-reduction gearbox-clutch assembly to drive the wheel. The aircraft’s own auxiliary power unit, or APU, provides the electrical power needed by the motor. The APU is actually a gas turbine/generator unit, generally located in the fuselage tail, that provides the electrical power needed to start the jet engines, power air conditions and supply electricity for other onboard systems, mainly on the ground when the jet engines aren’t operating. With this new system, we can also do away with the tractors that tow the aircraft after the doors are closed at the loading gate. In other words, the aircraft taxis using only electric power until just a few minutes before takeoff – and then again after landing, right after it leaves the runway.
Among the key benefits of this electric taxiing system:
- Airplanes will be able to push back from the gate and go faster.
- Fuel costs and related equipment costs such as tugging, brake wear and carbon emissions taxes will decline.
- Airlines will save “several hundred thousand dollars” per aircraft a year.
The two companies said that they will initially focused on narrow-body aircraft, which are used for short-range flights and are generally more sensitive to fuel costs.
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