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Electric airplane sets ascent record with Siemens drive system

An electric-drive Extra 330LE aerobatics plane recently set a world record in ascent in the category of “Electric aircraft weighing up to 1,000 kilograms. The pilot reached an altitude of 3,000 meters in only four minutes and 22 seconds, beating the previous record by one minute and 10 seconds. The airplane rose into the air at 11.5 meters per second.

The plane is equipped with a SP260D electric drive system from Siemens that has a continuous power output of 260 kW, continuous torque of 1,000 N·m, weighs only 50 kg, and thus offers an excellent power-to-weight ratio. (Earlier post.) Pilot Walter Extra broke the previous record set by the American pilot William M. Yates in 2013. The World Air Sports Federation—Fédération Aéronautique Internationale (FAI)—recognized the record-breaking flight.


This is a milestone on the path to electrification in aviation. This enormous achievement was possible only with digital technologies that enabled us to push our drive train to its technological limits.

—Frank Anton, who heads eAircraft within Siemens’ next4 startup unit

The Extra 330LE, which weights approximately 1,000 kilograms, serves as a test vehicle for the new drive. Its first public flight was in July 2016. (Earlier post.) For Siemens AG eAircraft, this record is proof of the performance of the SP260D drive system and its efficient integration into the airplane built by Extra Aircraft OEM.

The Extra 330LE two-seater will be the test aircraft for the coming years, when the goal will be to analyze and further develop how the individual components of its propulsion system work together. Siemens will also bring the technology to its electric flight collaboration agreement with Airbus, which the two companies signed in April 2016. (Earlier post.)

They want to prove the technical feasibility of hybrid electric drive systems for regional aircraft with up to 100 passengers by 2020. This will require power ratings of up to 10 MW.

The two partners plan to develop hybrid electric regional aircraft on the basis of the record-breaking motor.

We expect to see the first aircraft with up to 100 passengers and a range of approximately 1,000 kilometers by 2030

—Frank Anton


Dr. Strange Love

ECI. Battery advances are following a logarithmic asymptotic path and will only reach half the energy density of current light oil based aviation fuels. The mass density will never compete either. FCs may possibly be competitive. Battery driven air transport will be short hops. Special purpose built sail planes can be built to stay aloft in-definitely on solar and batteries, but it is not transporting freight and/or many passengers.

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DSL if battery energy density can ever reach 6.35kwh/kg as you suggest would be the physically possible limit it will be much better than kerosene at 12.7kwh/kg because the jet engine design is only 25% as efficient as the electric fan design everything considered. So a battery at 6.35kwh/kg will be comparable to kerosene at 25.4 kwh/kg.

Commercial viability is mostly about price per mile traveled but also speed. I bet there will be commercially viable options for a 1000 miles range supersonic battery electric aircraft with 400wh/kg batteries. It may take as long as ten years to develop an entire airplane for 100 passengers so if Tesla starts their development in 2020 they could start selling these airplanes by 2030. At that time Tesla should also be able to make 500 wh/kg batteries or better with the needed durability. I expect each plane to launch up to 10 times per day so 10,000 deep cycles for 3 years of durability are needed. The first plane will probably not be a normal passenger or cargo airplane but rather a corporate airplane with space for 6 people. It will sell well because it will be the only supersonic airplane in the world for corporate airplanes. With vertical launch you will also save time. You could probably do 1000 miles in less than 60 minutes.

Dr. Strange Love

I am sorry. I should have recognized "@Mahonj"s response. Mahon has already stated that the light oil Kerosene is "115x" more dense than current battery technology at 400wh/kg.

Given that wh/kg improvement will follow a Logarithmic Asymptotic limit of twice the current density, batteries will approach the limit of being "57x Less Dense" than current Light Oils.

No one likes Dead weight.

Your right, DSL, that extra weight is undesirable in vehicle design, especially airplanes, but incorrect when you conclude that the trade-off of cheaper flight won't be acceptable. I'm not addressing Transport or Cargo aircraft in my comments, but for GA, 400Wh/kg is the point at which battery electric airplanes find practical applications, and it just gets better from there.

Training flights, for example, are generally only one hour. A 100 mile commute (to work or to a weekend vacation home) will generally be less than an hour trip.

At 20% of the previous fuel cost, you'll see a lot more of them.

Account Deleted

DSL 115x is counterfactual and I even gave a source but apparently you don’t care about facts. You are so certain of yourself and what you want the truth to be. You really have lost it.

Dr. Strange Love

ECI. I agree with you on these applications. Electric drives by themselves are "Too Good", and should be used.

Change. You are talking to a PhD in EE, who initially was on the path to becoming either a BioChem or ChemE. Anyway, I am older and wiser now, and I don't always get the exact numbers, but I rely on practical experience. I think you should do some research in The Physical aspects of Ion Transport at the Lattice Level, and I think if you can understand the current Dimensional Densities of the the effective Redox Agents, and compare this with the Covalent Density of CH bonds in Light oils used in Combustion, you will come to the realization that there is no way that Batteries will ever achieve the Power/Aromic-Weight density of HydroCarbon based fuels. It is not possible unless you could Play God and Modify the Ground State Model of Quantum Physics (effective shell model and their associated spatial size) as we know it. Take courses in Material Science, Physical Chemistry, Modern Phys and the Standard Model, Quantum Physics and QED if you are so inclined and so on. You probably don't need all this course work do your analysis. HCs are packed chemical energy. (Btw, we are not comparing this to nuclear.)


Be careful about insults read the rules or be reported.


I think the 2170s coming out of the Gigafactory right now are pretty much at 300 Wh/kg, and that's with old-skool chemistry. Once the final hurdles of lithium sulphur are sorted out, it's a quick step up to 500-600 Wh/kg. Batteries don't need to match the energy density of kerosene because the motors are 3x more efficient.

Dr. Strange Love

Right now the energy density differential is about 2 orders (100x). @Mahonj mentioned a 115:1 differential. Even if you reduced the differential to 50:1 and applied the 3:1 efficiency factor, you are 16:1. This is still a very large difference. And also with batteries, your weight is always a factor, contrary to fuels where the products of combustion are exhausted and the craft becomes lighter.

There is an Asymptotic limit to battery energy specific density, and it is probably 40 or 50 to 1 worse than Kerosene. I don't see it getting much better. The Ion chemical Redox agents possible and substrates don't exist.

Agree with your energy density comparisons DSL, but as with autos, the manner of use can shift when the economics dictate it must.

Under a fixed-power regime (generally 75-80% of max for cruise flight) the efficiencies of stop and go are lost, but landing as heavy as takeoff is an easily solved problem. Drones are doing it right now today. EADS is on a path to building a twin engine trainer that will absolutely re-ignite GA. Truly the most exciting thing to happen in aviation since Burt Rutan.

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Clett I think you are nearly right with the energy density of Tesla’s 2170 cells at 300wh/kg. I have found two sources to confirm that. One is a new one where CTO Straubel says that the Model 3 will improve the energy density of the battery pack by 30% over Model S and X. The other is an old green car congress story about Tesla and Panasonic battery development cooperation that shows that the 18650 cells with enhanced nickel cathode and silicon anode was 252wh/kg (=(1000/54)*13.6). That was state of the art in 2013 to 2014 but I still think this is what is used in Model S and X today. Tesla needs to test these state of the art cells a lot before they dare to use them for production cars (a battery error could bankrupt Tesla so they need to be extremely careful). If you multiply that with 1.3 we get 327wh/kg for Tesla’s new 2170 cells.

Tesla new Powerpack2 got 210kwh up from 100 kwh for Powerpack1 and it kept its dimensions. That pack made the shift from 18650 cells to the new 2170 cell but also got better packaging tech.

If I am right about the above it also means that Tesla could make a 130kwh option available for Model S and Model X when it transform to these new 2170 cells for its battery pack. Tesla has to buy 18650 throughout 2017 from Panasonic but we could see the new battery option for Model S and X in 2018.

Roger Pham

Dr. Strange Love must have referred the 115:1 energy:weight ratio as between Liquid Hydrogen (LH2) vs Li-ion battery at 400 Wh/kg, though getting 40 kWh per kg HHV of H2 divided by 0.4 kWh/kg of Li-ion would only give 100:1 ratio.

But please know that LH2 is the future of aviation, due to the extreme weight advantage of LH2 vs kerosene jet fuel, of 3:1. Foam insulated container for LH2 is very light, as used in NASA's rocket. The reduction in fuel weight itself will double the payload:fuel for airliners and airtransport planes. The H2 can simply be burned in current jet engines with some modification, at around 50% thermal efficiency, which is comparable to the efficiency of the latest large-size turbofans. With LH2 costing $4 per kg and JP4 costing around $2 per gallon, the fuel cost per lb of payload is comparable.

Look to LH2-FC electric power as a way to significant boost payload capacity of General Aviation aircraft. Imagine carrying 1/5 the fuel weight for comparable range, for example, 500 lbs of AVgas fuel can be reduced down to 100 lbs of LH2 to travel 1,000 miles in LH2-FC electric aircraft! How is that doing for your payload capacity, eh?
Your 2-occupant aircraft at full fuel load now can carry 4 adult occupants with luggage to travel 1,000 miles.
NASA is paying about $4 per kg of LH2. So, you can carry twice as much payload while paying 1/2 for fuel cost, or FOUR-fold payload to fuel cost ratio.


10 tonnes of cells at 300 Wh/kg usable = 3 MWh.

That's enough to keep a 2,000 hp engine at full output for 2 hours, or a 1,000 hp engine at max for 4 hours. Yes it makes for a heavy aircraft, but it's still easily enough to keep an efficient e-fan powered intercity jet at reasonable speed (say, 350 mph) for 500-1,000 mile hops.

Dr. Strange Love

Roger. What is the reasonable life of the LH2 container before it must be replaced? What is the risk of letting a full or partial charge of LH2 remain unspent for long periods?

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@DLS Musk thinks the differential can come down to about 1/7 using 400wh/kg batteries as he said 1000 miles should be possible. The reason is some or all of the 6 reasons I listed above. I trust Musk on this more than I trust you. He understands the involved dynamics better than you do. That said it is still a large differential so military airplanes will continue to use kerosene as long as it is the most capable fuel as it obviously still is and will be for decades ahead. Small electric airplanes are already here and they will get bigger and faster as the wh/kg of batteries is improving. The breakthrough supersonic high altitude battery powered aircraft will come after 2030 when practical high cycle life batteries are over 400wh/kg. Tesla could be the first to make it. However, the first such plane will probably just be a “corporate jet” with space for 6 to 12 people.

By the way I also have a PhD but in mathematical economics. My interest for the natural sciences is just a hobby because it fascinates me more than most things. With your background you should know more on that area than I do. However, I am very careful about not saying anything that I can’t verify. I always check my sources and questions everything I think I know or others think they know. And I get angry when I see other PhDs slip on that ground.

@Roger it is the low volumetric energy density of hydrogen that makes it unsuited to use as an aviation fuel. At 700 bar it is only 1.5kwh/l. However, you need large cylindrical tanks so 50% volume is lost and then we get down to 750wh/l which is much less than the over 1000wh/l of Tesla’s 2170 cells. Then there is the problem of inefficient jet engines compared to the electric fan and it gets even worse. And the fuel is also impractical to handle. If you use liquid hydrogen you would need to boil off the tanks between each landing as they would otherwise explode. That boil off may need to be a controlled burn to prevent explosions. It will be wasteful. If you use pressure tanks they are used up after typically 1000 refills and need to be replaced. Replacing the fuel system in an airplane may cost more than buying a new plane. 1000 refills is not durable enough for an aircraft that needs to launch many times a day to be economical. Hydrogen may find practical use for stationary purposes like seasonal storage of renewable energy. However, for mobile applications it does not have a future. It is also a poor rocket fuel. LNG or kerosene is much better. SpaceX will use LNG in all of their future rockets. Currently it is kerosene.


OK, the figure of 115x for LiIon vs Kerosene energy density was wrong, so please discount it. A figure of 39 - 51 would probably be better. The range is because we do not know the battery pack density for current battery systems. The cell density of current 18650 cells is 250 wh/Kg. This yields a factor of 51x at cell level (not battery pack level). If you multiple the 250 x 1.3 (as people are suggesting for 2170 cells), you get 39x at cell level.
However, cells are not high voltage battery packs so we probably have to allow a margin for that.
Then you have to move very large currents and voltages from the batteries to the controls to the motors etc.

Here is a link to a story in AWST today.

From the article, it looks like hybrid aircraft have better performance but are very hard to program, pure battery planes are easier to program, whatever about performance.

Account Deleted

I got a new idea for how to make a long-range and very large supersonic battery electric aircraft. The two stage design I described above should not be 100% battery powered. The first stage should be like a first stage Falcon 9 rocket, however, upgraded with the more efficient and durable raptor engine that burns LNG which can be made by synthesis of renewable hydrogen and atmospheric CO2 so that it is CO2 neutral. It also burns far cleaner than the kerosene engine of the current Falcon 9 rocket. LNG is also a very affordable fossil fuel at 1/3 the price per energy content compared to kerosene.

The idea is to put a large supersonic battery electric aircraft on top of that falcon rocket and launch it vertically of cause to 50,000 feet at mark2. After that the battery electric airplane takes over and get into its cruising 72,000 feet horizontal orbit still at mark2.

The 1st stage falcon rocket falls back and gets refueled for another takeoff after 30 minutes of refueling and maintenance work.

The reason I no longer believe in a battery electric 1st stage is that it is inefficient to have a possible 100 ton first stage land vertically after falling from 10 miles from above. You spend a lot of energy making it safely back. The falcon rocket 1st stage will have spend like 90% of its LNG during takeoff so its total weight will have dropped by over 80% and therefore it also takes far less energy to land it vertically.

This is what Musk has in mind I am sure of. It all fits so well and it can explain why he believes the 1/7 differential is possible with just 400wh/kg. This is Musk’s secret design.

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Then at second thought I feared that the cost of liquid oxygen could be a show stopper for the above. I goggled it and found a source that says NASA only pay 16 cents per kg of liquid oxygen so I don’t think that will be a show stopper for rocket launched airplanes. We need highly reusable rockets (over 1000 launches with the same rocket) but SpaceX should have that by 2025.

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@Roger liquid hydrogen as a rocket fuel for a 1st stage launch of a battery electric aircraft may actually be a good idea if not for the high cost of hydrogen. The hydrogen rocket engine is very efficient and we only need to go 10 miles up at mark 2 and then fall back so air drag of a short and fat liquid hydrogen 1st stage booster rocket will not be a problem. It is actually an advantage when it falls back that it has poor aerodynamic as that will slow down the fall and require less fuel for the safe landing. Also hydrogen burns very clean so no cleaning is needed of the rocket engine after each launch. An inspection of the integrity of the engine may be all that is needed for a re launch of such a rocket. Kerosene rockets are full of dirt after launch and need a lot of cleaning. LNG is much better and H2 would have no issues in this regard. However, the show stopper for hydrogen is still the cost. 4 USD per kg for natural gas reformed hydrogen is much too much for mass market aviation.


I am not sure that you would want to subject a plane load of passengers to the G forces of a rocket takeoff.
I am not sure that you could turn around a rocket booster in 30 minutes - whatever about a 737 or A320.

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@mahonj I think it will be super fun. A true roller coster experience. I do not think that mark 2 at 10 miles is that much. A Tesla can do 0 to 60 mph in 2.4 seconds and people do not have problems with that. You do not need a pressure suit or anything like that. Some very old people may not like that they need to sit 90 degrees up at launch. That may be a little scary for some. They should travel in a driverless buss instead. The acceleration will not be a big problem. You can travel 1000 miles in just 60 minutes. This is progress.

I do not know how to calculate the needed G force to get to Mark 2 at 10 miles up vertically but if someone can please post it so we can see if there is a problem.


It shouldn't be to difficult to increase batteries performance from 333 Wh/Kg to 1000+ Wh/Kg by 2030 or so.

If so, the possibility of more efficient small training e-planes (by 2025 or so) and 8 to 12 passenger GA/Business e-planes (by 2030 or so) will become a reality.

Loop (1000 miles/h) and ultra fast (300 miles/h)passenger FC e-trains could replace many current large Jet Planes with less pollution and noise. Current airport infrastructures could be used as major pick-up and delivery points.

Roger Pham

@Dr.Strange Love,
Apparently, the lifespan of the LH2 tank should be good enough for Nikola Motor to consider the use of LH2 in semi-trucks. Furthermore, the LH2 tank can be designed to be easily removed and replaced at regular intervals to ensure safety. Having a thin aluminum inner layer and polyurethane foam outer layer should be cheap enough and light enough.
Boil-off rate is insignificant at the size of LH2 tank required for an airliner. The APU (auxillary power unit) (which could use a fuel cell) can use the H2 evaporating to make electricity and have a plug-out to power the airport and the city as well, while the plane is parked, until the next flight.

NASA study showed that a LH2 spherical tank a foot in diameter with 1" foam insulation takes about 6-8 hrs for complete boil off. If you triple the insulation thickness,it would take a whole day for boil off, and with ten-fold volume to surface ratio, it would take 10 days for complete boil off.

Please read my reply to Dr. SL above for concern about LH2 tank durability and boil-off.
Just use the LH2 in existing jetplanes would be the cheapest option. Designing new airliners takes $10 Billions, like the Boeing 777, that use conventional turbofan tech. Designing a completely novel and unconventional system may cost a lot more than that.

Due to the much lower loaded weight of a LH2 jetplane, the wings, the tails, the landing gears, and the engines can all be around 60% the weight of previous sizes, causing even further reduction in airplane gross weight and hence even lower fuel consumption...probably 30% the fuel consumption per mile in comparison to a kerosene powered plane for a given payload weight, so you can actually save on fuel cost...You pay double for fuel cost per energy unit but your plane only consumes 30% of the energy per mile.

LH2 seems to be the best option for both small aircraft as well as for the largest airliners. At the end of a flight, any LH2 remaining in a small aircraft can be pumped out, and the plane can taxi back to the hangar using battery power.
Of course, electric trains will save more energy than jetplanes, but we're discussing air travel here.

Account Deleted

I gave it more thought. The rocket booster stage for the electric aircraft is not going to happen anytime soon and likely never will. The problem is the risk of an exploding booster rocket. It will happen so you need a large area around the launch site to be clear of people and buildings. Also how will you save the passengers in the electric aircraft on top when the rocket booster explodes? In a normal space rocket with people the passenger compartment is able to detach and fly away at enormous speed using its own rocket engines to avoid the blast of the exploding first stage. The astronauts need to be in pressure suits to survive the resulting G forces probably over 20 G for a few seconds. This is not possible with a much larger electric airplane with civilians in it. This is a show stopper for rocket boosted electric airplanes.

However, an electric booster aircraft is possible and the idea of using a superconductive cable to power the first quarter mile during vertical takeoff is also practical.

I also read up on what Musk said about electric aircrafts development. He wants to make an electric supersonic vertical takeoff and vertical landing aircraft. That means no landing gear with wheels on it. The supersonic part of it also means a quadcopter design is impossible. The aircraft will have to look like a falcon 9 rocket with wings on it optimized for high altitude supersonic speed. So instead of rocket engines it will have a large fan at the bottom and instead of conventional elevator and rudder it will have steering fans. The booster rocket could also be like that about from not awing and passenger compartment but just be one big battery with wings optimized for slowing the speed of the fall back. Because it has wings it could fly back in a large spiral maneuver while charging its batteries with the main fan running backwards.

@Roger you can’t retrofit a hydrogen powered aircraft from an existing aircraft. A complete redesign is needed to take any passengers in. A LH2 retrofit of a 447 will end up with seating for 30 instead of 400 and the fuel with be 2 times as expensive as kerosene for the same distance traveled. Something like that. There is no way around spending 20 billion USD or so to make a large LH2 aircraft and it will still be uneconomical to kerosene jets. Battery aircrafts has a change to compete on price and speed but not on range at least not until we reach over 7*400 =2800wh/kg which may never be possible.


Lithium 0.36–0.875 MJ/kg 4.32 MJ/L

Jet fuel 46 MJ/kg 37.3 MJ/L

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