Hybrid Airplane Concept Moves Forward

Diamond Aircraft and electronics giant, Siemens, are moving forward on plans for an experimental hybrid airplane based on Diamond’s existing DA 40 twin engine aircraft, reports AVWeb.

The plan is to mount two electric motors on pylons connected to the front engine compartment rather than positioned in the normal position on the wings. That arrangement would permit a single diesel engine driving a generator to be mounted in the usual engine location.

According to Diamond CEO, Christian Dries, the “two electric motors… each weigh less than 30 pounds but deliver 85 kilowatts or 114 horsepower. The aircraft will use some 440 pounds of lithium ion batteries mounted where the backseat would normally be, so it will be limited to two occupants. Typical cruise speeds [would be] 110 to 120 knots, [and] the airplane would have 10 hours of endurance, burning 6 to 7 liters (1.8 gallons) per hour.” That is about one tenth the fuel consumption of a conventional twin engine small airplane that consumes nearly 11 gallons or fuel per hour at normal cruising speed and altitude.

During the testing phase, the companies will experiment with some of the ideas NASA has developed for its GL1o electric vertical take off and landing (VTOL) prototype.

Did it seem just a few years ago that the concept of a diesel electric hybrid airplane was too far out to even consider? Not any more.

Siemens and partners build first aircraft with series hybrid electric drive

Siemens Drive Technologies Division supplied the integrated drive train for the first series-hybrid electric aircraft. Source: Siemens. Click to enlarge.

Siemens, Diamond Aircraft and EADS have built an aircraft equipped with a series hybrid electric drive system. The partners are presenting the two-seater motor glider DA36 E-Star at the Paris Air Show Le Bourget 2011 (until 26 June) in daily flight shows. The aircraft was built to test the hybrid electric drive concept.

The technology, which is intended for later use also in large-scale aircraft, will cut fuel consumption and emissions by 25%, compared to today’s most efficient aircraft drives, according to Siemens.

Based on Diamond Aircraft’s HK36 Super Dimona, the E-Star’s propeller is powered by a 70 kW electric motor from Siemens. Electricity is supplied by a small Wankel engine from Austro Engine with a generator that functions solely as a power source. A Siemens converter supplies the electric motor with power from the battery and the generator.

Fuel consumption is low since the combustion engine always runs with a constant low output of 30 kW. A battery system from EADS provides the increased power required during takeoff and climb. The battery is recharged during the cruising phase. The plane is able to start noiseless with the electric drive and can fly over long distances. During test flights, it was airborne for about two hours.

The next development step will be to further optimize the entire drive train. Siemens researchers are currently working on a new electric motor that is expected to be five times lighter than conventional drives. In two years, another aircraft is expected to be equipped with an ultra-light electric drive.

Siemens’ Drive Technologies Division has already used integrated drive trains in other applications like marine drives. The know how gained in these areas has now been applied in the aviation industry as well. Combined with the corresponding product portfolio, the components of the drive train can be optimally adjusted to one another.

Source: Green Car Congress