World’s First In-Flight-Recharging Hybrid Electric Plane Takes To The Skies – Video

JAN 9 2015 BY MARK KANE 18

World's First In-Flight-Recharging Hybrid Electric Plane

World’s First In-Flight-Recharging Hybrid Electric Plane

The aviation industry seems far behind automotive in terms of drivetrain electrification, however the first projects are starting to knock on the doors.

Researchers from the University of Cambridge, in association with Boeing, recently presented an aircraft with a parallel hybrid engine, which according to the article is the first to have recharge mode to recharge its batteries in flight.

The whole concept of the hybrid single seater motor glider make sense because aircraft need most power while taking off and then need significantly less power for cruising. This mean that the oversized petrol engine works inefficiently most of the time.

The team designed the drivetrain with a small 7 kW petrol engine and 10 kW electric motor, powerful enough for take off and then efficient operation in the air, as well as being able to recharge batteries in flight for the next take off. The result is up to 30% higher fuel economy.

Who knows, maybe one day we will see commercial electric and plug-in hybrid aircraft.

“The demonstrator is based on a commercially-available single-seat aircraft, and its hybrid engine was designed and built by engineers at Cambridge with Boeing funding support.”

“The aircraft uses a combination of a 4-stroke piston engine and an electric motor / generator, coupled through the same drive pulley to spin the propeller. During take-off and climb, when maximum power is required, the engine and motor work together to power the plane, but once cruising height is reached, the electric motor can be switched into generator mode to recharge the batteries or used in motor assist mode to minimise fuel consumption. The same principle is at work in a hybrid car.”

“The hybrid power system in the Cambridge demonstrator is based on a Honda engine, in parallel with a custom lightweight motor. A power electronics module designed and built in the Engineering Department controls the electrical current to and from the batteries – a set of 16 large lithium-polymer cells located in special compartments built into the wings. The petrol engine is optimally sized to provide the cruise power at its most efficient operating point, resulting in an improved fuel efficiency overall.”

“Test flights for the project took place at the Sywell Aerodrome, near Northampton. These tests consisted of a series of ‘hops’ along the runway, followed by longer evaluation flights at a height of over 1,500 feet.”

Dr Paul Robertson of Cambridge’s Department of Engineering, leader of the project, stated:

“Although hybrid cars have been available for more than a decade, what’s been holding back the development of hybrid or fully-electric aircraft until now is battery technology. Until recently, they have been too heavy and didn’t have enough energy capacity. But with the advent of improved lithium-polymer batteries, similar to what you’d find in a laptop computer, hybrid aircraft – albeit at a small scale – are now starting to become viable.”

Marty Bradley, Boeing’s principal investigator for the program, commented:

“Our mission is to keep our sights on finding innovative solutions and technologies that solve our industry’s toughest challenges and continually improve environmental performance. Hybrid electric is one of several important elements of our research efforts, and we are learning more every day about the feasibility of these technologies and how they could be used in the future.”

More on the project can be found here.

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18 Comments on "World’s First In-Flight-Recharging Hybrid Electric Plane Takes To The Skies – Video"

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Spoken purely from a novice, but I think Hydrogen would be more viable for aircraft. Especially of we are thinking about the environment and doing away with fossil fuel engines. Batteries would just take too many batteries for electric.

You can find Elon Musk’s response to that here

Hydrogen is a fossil fuel. It comes from coal and natural gas.

Hydrogen CAN BE extracted from fossil fuel, and yes in most cases that’s true because it is still the cheapest way to get hydrogen.

But hydrogen itself isn’t fossil fuel per definition, or an even an energy source (here on earth). Hydrogen can be extracted by splitting water molecules with electricity, making hydrogen fuel as clean as it’s source. Although there are energy losses in the extraction of hydrogen with electricity, and that is just one downside of hydrogen as a fuel.

“The aviation industry seems far behind automotive in terms of drivetrain electrification”


Please tell me you know how regen works in hybrid and electric cars, and you’re not the *complete* dunce you just made yourself out to be by saying this?

The fact is, that there’s no energy for an airplane to *recover* in the first place. There’s no stop and go in the air, you just accelerate to gain lift, reach cruising altitude, then nearly coast to a stop (the entire final approach is done with your engine nearly at idle) at your point of landing.

On top of this little gaffe, there’s the minor detail that efficient aircraft are extremely sensitive to weight. They absolutely *need* the lightest possible fuel source. And that’s not batteries.

There’s a reason that the only aircraft to sport electric or hybrid engines are basically sailplanes. And that same reason is why passenger aircraft will never be electric.

I don’t think there are any blunders from Kane or the University. Looks to be a solid design. As far as commercial flight, 400 Watt-hours per kilogram is where Elon Musk declares the market to be “compelling”. Check out the link above. Most manufacturers agree with this post. Decades away for commercial flight, but definitely not off the table. In fact, Boeing and Airbus seem to be working on designs expecting the battery density to be there in twenty years. This one is a different application though and seems to have merit.

During landing, and while in taxi mode on runways, there could be some recharging.

Commercial aircraft today should have electrically driven wheels for taxiing. Don’t start the main engines until nearly cleared for takeoff and shut them off as soon as the plane is off the main runway after landing.

and done:

Batteries are not currently used, but the main engines are shut off after landing and started at near the take-off point (American 757, you’re #3 for take off, you may start your marines now)! They use the APU, since it also powers lights in the cabin, avionics, hydraulics, and air conditioning.

“There’s a reason that the only aircraft to sport electric or hybrid engines are basically sailplanes. And that same reason is why passenger aircraft will never be electric.”

Why do you use the word “never”? How can you look at today’s situation and conclude “never” for the future? That’s stupid, if you ask me.

I guess you think that airplanes will look the same, smell the same and sound the same in 100 or 1000 years? You just shouldn’t use the word “never”. You made a terrible conclusion.

Strange, what you write.
Event though the reasonning seems good, it ended with the only viable flying being sailplane, wich need more than commercial plane to be light!
So you prove the contrary of what you intend to do.

This is why I read
Keep up the great work.

Seems like some solar panels on the main wing would be a good application. Probably not so useful in flight, but planes tend to spend much of their time parked in the sun.

And see: Worlds First Solar Powered Two Seat Airplane,,

Also see
For a Long Range Solar Goal!

For a more fun and useful Hybrid aircraft – see the Volta Volaré GT4,

EADS has done Hybrid aircraft before, too, and an all Electric Cri-Cri –

Pipistrel is building Award Winning Electric Aircraft, taking NASA’s prize, and they have a hybrid Aircraft in the works, too:
or here:

And, for more Electric Aircraft on-topic sources, try here:

He didn’t mention the best advantage of an hybrid aircraft, the potential availability of high peak power for vertical take-off in more then just a regular plane take-off. That is where hybrids can actually shine.

When I first read “World’s First In-Flight-Recharging Hybrid Electric Plane”
I had visions of the one with near flat batteries cruising up behind another with a set of jump leads trailing behind it 🙂

I pictured an EREV with a diesel adding thrust for takeoff and then just plugging away in the tail with a CVT spinning a genset as fast as it could turn. Hell, just removing the jet-fuel requirement would hafta’ help efficiency-wise, but no doubt diesel fuel is as anchor-heavy as the batteries.
But having motors that can respond so much faster to changing conditions that ICE/jet -seems- like it could pay back in efficiency.