Siemans just unveiled the world’s first true plug-in hybrid-electric airplane, which has an engine that resembles the Chevy Volt’s. The airplane took its maiden flight on June 8 at the Wiener Neustadt airfield in Vienna, Austria and could reduce fuel consumption and emissions by 25% — that number is taken from statistics of the most fuel efficient aircraft available. This proven concept could do for the air what the Chevy Volt has done for the roads, and provide a nice segue from gasoline power to electricity by splicing the two technologies together.
The plane runs off of an electric motor that is initially powered by a battery and then once depleted, is fed by a gasoline generator. The aircraft was modeled after Diamond Aircraft’s HK36 Super Dimona and is the only one of its kind in the world. In addition to being much more fuel efficient the two seater is able to take off while powered only by electricity which could help with noise pollution problems around airports.
Currently they’ve only installed the technologyin this small, two person motor glider, but Siemens has plans to go bigger. “The first thing we want to do is test the technology in small aircraft. In the long-term, however, the drive system will also be used in large-scale aircraft,” said Dr. Frank Anton, the initiator of electric aircraft development at Siemens. The motor glider’s propeller is powered by a 70kW electric motor and the plane’s battery is recharged during cruising phases to allow for even longer flights.
I'm an EV geek & pilot and have to agree with Zeppflyer. While the research is fun and interesting it really doesn't have any practical applications until battery energy density actually gets close to the incredible energy density of fossil fuels. It's the wrong way to go in the near term for aircraft. Synthesized, CO2 neutral liquid fuels is the right answer (as well as FINALLY moving away from leaded fuels). Caeman, the noise of the airplanes is 99% the propeller chopping through the air. Very little engine noise except in jets and that noise is the exhaust being blasted out of the back of the engine at speeds in excess of the speed of sound, not the turbines inside the jet engine spinning. So, even if the engines themselves were entirely electric, there's little to no chance it would noticeably effect the noise you hear on the ground.
OK. At first, I couldn't figure out how on Earth this could make sense, but I can see now how bits of it *could*, possibly, be useful. Potentially, yes, it could make sense to have a gasoline engine not powerful enough to carry a plane aloft, but only enough to maintain altitude while the more powerful electric engine draws down a battery during climb. Other technologies used to solve this problem have included rocket boosters, secondary engines which were shut off while cruising (See the Voyager.)and even having larger planes carry small ones aloft. The difference with these techs is that the weight is partially or entirely discarded once the plane reaches cruising altitude. Even with a secondary gas engine, the fuel that it burns is weight that doesn't have to be carried throughout the entire trip. With an electric takeoff assist, though, you have to lug the full weight of the battery and electric motor for the entire flight. And, as has been said about the Volt, its 400lb, $7,000 battery can drive the car almost 40 miles, but so can one roughly 6.5 lb gallon of gas. Furthermore, a pure series hybrid seems a poor choice. The Inhab distillation of the actual article states that this resembles the technology used on the Volt. This is not quite so. While it was originally advertised as such, the production Volt is not a pure series hybrid. That is, in some conditions, the motor does directly turn the wheels, bypassing the electric system entirely. A parallel setup like this would make more sense than a pure series model since, during the 90% of the time when an airplane is operating at a constant, fuel efficient cruise, it makes no sense to lose a good chunk of the engine's power by routing it through a generator, battery, and electric motor rather than coupling it directly to the prop and allowing the electrics to sit there until needed for another climb. Basically, the arguments against hybrid cars (complexity, weight, and only seeing increased efficiency under conditions of extreme load) apply even more so to airplanes. Power density on batteries is not yet high enough to drive an airplane for any useful distance and a tiny fraction of an airplane's flight is, unlike the stop and go of a car commute, a chance for a hybrid system to shine. (Not to mention that there is no way to do regenerative breaking, which is a big part of the efficiency of a hybrid) Once batteries have become significantly more efficient the use of electric-only airplanes will make sense, but, as a transitional technology, the series hybrid power train seems to be of very limited utility when it comes to aircraft.
Anything to make the planes quieter is a good thing.