[glabifrons]

I don't see how hybrid-aircraft make any sense.

The whole point of hybrid cars are the fact that you're only on the throttle periodically. You start, stop, speed up, slow down all the time (especially in S. Florida!). Normally when you're slowing down, you're burning off the energy as heat (friction from the brakes), etc. Adding an electric motor/generator to this allows you to recapture energy that is normally wasted slowing back down, so it can be reused to re-accelerate back up to speed. This is why hybrids (unlike non-hybrid cars) get better fuel mileage in town than on the freeway.

Aircraft, on the other hand, are at full-throttle on takeoff, and close to 3/4 throttle during the vast majority of the flight. There is no slowdown to recoup the energy until coming in for a landing. @beloch has already done the math showing the electric range would be downright miniscule, so there's very, very little to be gained here.

Until we have some utterly astounding advances in battery (or more likely, supercapacitor) tech (probably via graphene), this won't really be a cost-effective solution.

However, this would be an absolutely incredible motor for electric car conversions. Imagine a pair of these (each powering an axle)... it would be considerably more powerful than even the Tesla Model S P85D.

[mikeash]

Regenerative braking is only one advantage of the hybrid approach. The other significant advantages are:

1. The engine can be sized for average output, not peak output, which makes it more efficient.

2. The engine can stay closer to its optimally efficient RPM.

3. Because RPM variation is smaller, and because power requirements are smaller, you can use more efficient engine cycles like the Atkinson cycle.

I'm doubtful that the advantages will be worth the extra weight. #1 is not going to be as big of a deal for an airplane, since as you note, power output is a decent fraction of the maximum during cruise. (In contrast with a car, which might have a 200hp engine but only use 30hp of that in cruise.) But it should count for something. #2 might make a nice difference paired with a variable-pitch propellor. #3 gives a decent efficiency boost. Put it all together and it doesn't seem likely to be worth the extra weight, since that counts for so much in an airplane, but it's not completely absurd.

Note for the Tesla comparison that the limiting factor in the P85D's power output is the battery, not the motors. Lighter motors would certainly be good, but it'll be a small effect. If you really want more power, you either need a bigger battery, or a battery chemistry that can discharge faster.

[nether]

Electric aircraft can recharge in flight from the sun. This will mostly be long endurance, high altitude utility aircraft, like Facebook/Titan Aerospace's wifi UAV or surveillance drones that can stay airborne indefinitely. These aircraft can be pseudo satellites without requiring a rocket launch. They must be extremely low in drag and weight efficient, with powerplant weight being a major issue because previously large electric motors have not had application in aerospace and have not been weight optimized as gas turbines have. Siemens has seen the growing market (QinetiQ Zephyr for another example) and is responding to it. We definitely won't be seeing any passenger aircraft electrically propelled anytime soon.

[glabifrons]

The article specifically mentions using this motor for hybrid passenger aircraft (which is what my post addressed). I mentioned nothing about UAVs or solar power (which is only possible with an enormous wing/fuselage ratio).

FTA: "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

[rasz_pl]

This is 200KW motor, you might want to check the size of 200KW solar installation.

[thrownaway2424]

These could dramatically improve the throttle command response of the aircraft and make the aircraft far quieter on departure and approach. Civil aviation is one of the most annoying hobbies that anyone has ever conceived, from the perspective of people who live near airfields. If this tech opens up the possibility of living near and airfield but not having to put up with the sound of private pilots coming and going all day long in Korean-War-era airplanes, that would be nice for those people.

[davepage]

> from the perspective of people who live near airfields.

Things more annoying than airplane noise: * People who voluntarily choose to live near airports (which predictably have associated airplane noise), then complain about it. * The ubiquitous, intentionally loud motorcycles (at closest approach, much louder than any small airplane, due to power law d^-2), which all get a free pass for some bizarre cultural reason, and are largely inescapable.

Some of the airplane noise perception problem is jealousy, and is easy to fix: go down to the airport, chat someone up, and they'll give you a ride.