A new type of electric motor designed specifically for use in aircraft could help make electric-powered passenger flight a reality its developer has claimed.
Developed by researchers at Siemens in Germany the motor, which weighs just 50kg, delivers a continuous output of about 260kW – five times more than comparable drive systems.
The team claims that the motor’s power-to-weight ratio of 5kW per kilogram could enable larger aircraft with take-off weights of up to two tons to make use of electric drives for the first time.
Electric motors of comparable strength that are used in industrial applications typically deliver less than 1kW per kg, whilst the performance of drive systems used in electric vehicles is about 2kW per kg. Siemens claims that it achieved the improved performance by employing advanced simulation techniques and reducing the weight of every component of the system.
Because the motor delivers its performance at rotational speeds of just 2,500 revolutions per minute, it is able to drive propellers directly without the use of a transmission.
“This innovation will make it possible to build series hybrid-electric aircraft with four or more seats,” said Frank Anton, head of eAircraft at Siemens Corporate Technology, the company’s central research unit.
The motor is scheduled to begin flight-testing before the end of 2015. In the next step, the Siemens researchers will boost output further. “We’re convinced that the use of hybrid-electric drives in regional airliners with 50 to 100 passengers is a real medium-term possibility,” said Anton.
In 2013, Siemens, Airbus and Diamond Aircraft successfully flight-tested a series hybrid-electric drive in a DA36 E-Star 2 motor glider for the first time. The test aircraft had a power output of 60kW.
Siemens is not alone in pursuing the goal of electric flight. As previously reported in The Engineer, Airbus has made big strides with electric propulsion technology. Its two-seater E-Fan aircraft performed its first public flight last year (2014) whilst the company has a longer-term stated vision to develop a 90-seater electric passenger plane. Meanwhile the Solar Impulse aircraft, which is currently attempting the world’s first solar-powered round the world flight is also helping to generate interest in the concept.
Click here to read our feature on Airbus’ E-Fan concept
Click here to read our Q&A feature on Solar Impulse
This seems more suited to LTA craft with a large solar collecting area on top to assist other propulsion systems and possibly greatly extend the range or flight duration.
It would need a major improvement in compact and lightweight electric accumulators before 50-100 seat HTA craft would have adequate range.
I don’t know what they are thinking, but won’t the extension cord be rather long for this flying electric lawn mower? 🙂
All joking aside, 5kW/kg mass is an outstanding accomplishment the team members should be saluted for. Icarus may finally get wings that won’t melt in the sun.
Yes the motor is certainly light but when you add the batteries to power it then you will have a different equation.
This concept goes much farther than electric plane, or hybrid thermal-electric like the E-Thrust of Airbus.
If you look as SUGAR Boeing/Nasa report
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120009038.pdf#page=38
you see that LENR first integration should be as Hybrid electric.
Airbus is clearly interested as it have already joined LENRG ecosystem, and send it’s Chief scientist to LENRG conference in oxford (and will send him to Milano too).
Airbus Defense and Aerospace even hold a patent in that domain
DE102013110249
while Boeing clearly integrate LENR option in his own electric fan patents EP 2730501 A2
a race is in process, and electric engine is an intermediate requirement for LENR-electric hybrid planes.
another requirement is lightweight heat to electric conversion… Turbines or alike…
4kWth/kg is already achieved, so this put pressure on engine and turbines…
Chris Saint, the purpose of using a hybrid system similar to the Chevy Volt is that you do not need a large battery pack. With a small, efficient ICE, you can generate significant power to keep the smaller battery pack charged throughout the flight. The balance of battery weight to fuel weight can be adjusted to reach optimal performance for a given distance.
“I don’t know what they are thinking, but won’t the extension cord be rather long for this flying electric lawn mower?”
Actually – you could spiral the plane up to 40,000 feet on an electric chord, then the battery would take over for a controlled glide to its destination.
That would work for short haul – but might not be practical.
“…you could spiral the plane up to 40,000 feet on an electric chord…”
I’m not sure how a chord played on an electric guitar is able to power a plane…
A hybrid system would use very few if any batteries. Batteries release power slowly. The prime mover (ic, turbine, fuel cell) could do that. So kerosene remains as the main fuel. Electric storage would be in super capacitors. They don’t store so much energy but they can release it to the motor very quickly for take off and directional change. The prime mover would run at a constant rate, optimized for fuel efficiency so reducing size/weight, fuel costs and maintenance. Super capacitors are the game changer here; more than the electric motor. The motor is a response to the opportunity. Trains, trucks, trams, trolley buses, buses and cars can use this technology too.
8.2 kW/kg, 5 years ago…
http://www.launchpnt.com/portals/53140/docs/dual-halbach-motor-presentation.pdf
No one has addressed the class of plane this might work for. Jet engines have power to propell an aircraft very fast. I don’t see this possibility with an electric or electric-hybrid power system. Private aircraft and short range flights might justify such an approach but no one wants to be on a slow plane on a trans-Atlantic flight.
Editor – yes power chords as are played by AC/DC in a metal song . . . The kind that plugs into an outlet is a cord. 🙂
I have yet to see some good numbers for flight duration on batteries alone. The amps are too low for solar assist. So far I see the need for batteries to equal the weight of the passengers. We have a hybrid system that puts out 2 Hp per pound which keep the cells going 4 times longer.