Diamond's diesel-electric hybrid and other GA news
On 31 October Diamond Aircraft made the first flight of a multiengine diesel-electric hybridpowered DA40 that has been developed in collaboration with Siemens AG. During the twenty-minute flight the aircraft demonstrated all modes of operation, including hybrid, ‘charging’ and full electric flight, from takeoff. The main objective of the joint project is to develop an aircraft that has lower fuel consumption (thus higher efficiency), and a lower noise footprint. ‘The hybrid powertrain will allow for full electric takeoff capabilities without the added noise and pollution of a combustion engine,’ Diamond says.
The DA40 has been reconfigured so that a single combustion engine powers two independent electric drive systems, each comprising one motor, battery and inverter. Mounted on a forward canard, the two electric motors can jointly generate 150kw of takeoff power. A diesel generator in the nose of the aircraft can provide up to 110kw of power, and two 12kwh batteries mounted in the rear passenger compartment act as an energy storage buffer. Through a dedicated power lever, the pilot can control the energy flow between generator, batteries and motors, selecting either pure electric mode (generator off), ‘cruise mode’ (in which the generator provides all power to the motors), and ‘charge mode’ (in which the generator charges the batteries). On pure electric power the DA40 has an endurance of about thirty minutes, which the hybrid system extends to five hours.
Head of Flight Test Ingmar Mayerbuch, who piloted the aircraft, reported: “The first flight exceeded all our expectations. The combination of the hybrid powertrain and the configuration of the aircraft is just perfect. We reached 130 knots at medium power output and climbed to an altitude of 3,000ft.”
“This is the first serial-hybrid electric plane in the world with two electrically-powered free-stream propellers and one combustion engine,” says Dr Frank Anton, Siemens AG’S Executive Vice President, eaircraft. “A distributed propulsion architecture opens entirely new possibilities for the design of highly efficient planes−and we have now proven its technical feasibility. Serialhybrid electric propulsion systems and distributed propulsion architectures for us are the key to a more sustainable flight future also in higher power classes. The Diamond flying test bed will help us to understand the requirements for these new propulsion technologies and to be prepared for the challenges of larger-scale applications.”
The next flight tests will aim to determine the exact efficiency increase achieved in comparison to similar non-electric aircraft. The aircraft’s noise footprint will also be monitored. Future trials will gather knowledge on the practical operation of hybrid aircraft in different modes and their effects on efficiency, range, and energy consumption.
Head of Flight Test Ingmar Mayerbuch made the first flight
150kw (201hp) is available for takeoff, generator produces 110kw
Electric motors provide propulsion, nose houses diesel generator