Hybrid helicopter could take off electrically
We already have hybrid diesel-electric cars, buses and lorries. Could hybrid helicopters be next?
As well as being more fuel-efficient, a hybrid diesel-electric helicopter would be able to take-off and land on electric power alone, making it significantly quieter, claimed the EADS team, which presented the concept in full-scale model form at the ILA Berlin Airshow this week.
Developed by the company’s corporate R&D network, EADS Innovation Works, the hybrid helicopter concept uses electric motors to drive the main and tail rotors; these in turn would be powered by multiple diesel-electric generators and a pair of batteries, all controlled by power electronics for best efficiency.
The researchers propose using opposed-piston, opposed-cylinder (OPOC) diesel engines, which they say offer up to 30 percent better fuel economy than today’s helicopter turbine engines. However, other types of combustion engine could also be used.
The hybrid scheme would also allow the main rotor and its electric motor to be tilted forwards when the aircraft is cruising. This would minimise aerodynamic drag and therefore fuel consumption. Similarly, the tail rotor could be turned off at higher speeds when it is not needed, as the tail fin and rudder then provide stability and control.