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Electric drivetrains have the unique ability to recover energy, often used in braking for EV cars. Is there any corollary for recovering potential energy for el

Electric drivetrains have the unique ability to recover energy, often used in braking for EV cars. Is there any corollary for recovering potential energy for electric planes?

jxf 6y ago
The reason energy recovery in cars makes sense is that you're constantly stopping and starting. In a plane you definitely don't want the engine to stop running while you're in the air.
- manigandham 6y ago
  Isn't altitude ultimately a function of energy? If you're decreasing altitude wouldn't that be a decent amount of recovery? Gas turbines need to keep running to sustain combustion but electric motors can start and stop instantly with current flow; it seems possible to use this as part of the dynamic control of the aircraft.
  - dogma1138 6y ago
    You don’t change altitude frequently enough and even if you could recover 80% of the energy you spent on reaching cruising altitude when you perform your landing approach it won’t be much, and probably won’t be worth the extra complexity and weight of an energy recovery system. Unless we’re talking about very short flights the majority of your energy would be expanded at cruising altitude especially since electric engines have a fairly flat efficiency curve.
- LightG 6y ago
  Actually, why don't planes cycle climbing to a height, switch off the engines, glide for X miles, restart engines to climb, etc ... Pretty sure I used to do that when I used to fly in my Microprose F-15 and was short on fuel.
  - dogma1138 6y ago
    Because it’s not a very efficient or pleasant flight experience, and it’s probably too much of a risk.
  - greedo 6y ago
    Generally, you don't want to stop an engine that's running fine. It might just not restart...
rmelly 6y ago
Kindof. Currently used for emergency recovery: https://en.wikipedia.org/wiki/Ram_air_turbine https://en.wikipedia.org/wiki/Ram_air_turbine
sxates 6y ago
Potentially on descent, but I think it's a much smaller potential benefit in an airplane, and perhaps tricky because you don't want to extract so much energy that you lose speed and stall.
layoutIfNeeded 6y ago
Planes don’t brake (except for a brief moment while landing), so no.
bdamm 6y ago
There is at least one commercial EV aircraft that can do it, but frankly it won't be as big a deal as it is with cars. Cars are speeding up and slowing down all the time. Aircraft generally speed up, stay fast, and then slow down at the very end of the flight. And for most aircraft, the entire flight is powered from takeoff to landing. It could be useful in emergency situations where the pilot is at risk of overshooting the runway. For aerobatic aircraft it could be a big deal. High power motors and the desire to be as light as possible will probably drive power recovery and even crazier stunts at airshows.
phire 6y ago
Electric planes don't really need much breaking, except when coming in for a landing. At that point, your flight is over and you don't need any extra range.

Electric drivetrains have the unique ability to recover energy, often used in braking for EV cars. Is there any corollary for recovering potential energy for electric planes?

jxf 6y ago

The reason energy recovery in cars makes sense is that you're constantly stopping and starting. In a plane you definitely don't want the engine to stop running while you're in the air.

manigandham 6y ago
Isn't altitude ultimately a function of energy? If you're decreasing altitude wouldn't that be a decent amount of recovery? Gas turbines need to keep running to sustain combustion but electric motors can start and stop instantly with current flow; it seems possible to use this as part of the dynamic control of the aircraft.
- dogma1138 6y ago
  You don’t change altitude frequently enough and even if you could recover 80% of the energy you spent on reaching cruising altitude when you perform your landing approach it won’t be much, and probably won’t be worth the extra complexity and weight of an energy recovery system. Unless we’re talking about very short flights the majority of your energy would be expanded at cruising altitude especially since electric engines have a fairly flat efficiency curve.
LightG 6y ago
Actually, why don't planes cycle climbing to a height, switch off the engines, glide for X miles, restart engines to climb, etc ... Pretty sure I used to do that when I used to fly in my Microprose F-15 and was short on fuel.
- dogma1138 6y ago
  Because it’s not a very efficient or pleasant flight experience, and it’s probably too much of a risk.
- greedo 6y ago
  Generally, you don't want to stop an engine that's running fine. It might just not restart...

rmelly 6y ago

Kindof. Currently used for emergency recovery: https://en.wikipedia.org/wiki/Ram_air_turbine https://en.wikipedia.org/wiki/Ram_air_turbine

sxates 6y ago

Potentially on descent, but I think it's a much smaller potential benefit in an airplane, and perhaps tricky because you don't want to extract so much energy that you lose speed and stall.

layoutIfNeeded 6y ago

Planes don’t brake (except for a brief moment while landing), so no.

bdamm 6y ago

There is at least one commercial EV aircraft that can do it, but frankly it won't be as big a deal as it is with cars. Cars are speeding up and slowing down all the time. Aircraft generally speed up, stay fast, and then slow down at the very end of the flight. And for most aircraft, the entire flight is powered from takeoff to landing. It could be useful in emergency situations where the pilot is at risk of overshooting the runway. For aerobatic aircraft it could be a big deal. High power motors and the desire to be as light as possible will probably drive power recovery and even crazier stunts at airshows.

phire 6y ago

Electric planes don't really need much breaking, except when coming in for a landing. At that point, your flight is over and you don't need any extra range.