3 ms·

I agree it's unrealistic, but not because the plane might need "big energy" later -- I don't see how dropping the battery is any different than burning the fuel

I agree it's unrealistic, but not because the plane might need "big energy" later -- I don't see how dropping the battery is any different than burning the fuel? If the plane burns 25% of its fuel on takeoff and climb, then that fuel is gone. If the plane drops 25% of its battery capacity (which is now depleted) after takeoff and climb, that battery capacity was already depleted, it's just acting as dead weight.

dredmorbius 3y ago
The difference is that when you burn fuel, you burn fuel, and the mass exits the aircraft through the engine. When you discharge an electric cell, you're still carrying that electric cell with you. I suspect you're trying to express this and are fingering some other element of this concept as unrealistic, but that's not how your comment reads.
- Johnny555 3y ago
  I literally said that the depleted battery would be physically detached, I don't see how there is any other interpretation? I saw a concept once that had the plane drop the big battery after takeoff (maybe after reaching cruising altitude too) and let the battery fly back to the airport autonomously. Then it doesn't have to carry that dead weight for the entire trip. It's unrealistic because of all of the details in making a an autonomously flying battery pack that can detach from an aircraft in flight and do it with the kind of safety a civilian passenger aircraft demands.
  - dredmorbius 3y ago
    That's clearer.
  - notahacker 3y ago
    Apart from the detaching and flying a battery part, you've also got to seamlessly switch power source in midflight Otherwise you've depleted 25% of all your batteries and jettisoned a single battery pack, which (like the others) is 75% full. (That might of been a source of confusion).
    - Johnny555 3y ago
      That seems like the easiest part, flip the relays to disconnect the battery pack, evaluate remaining capacity and if the detachable pack is discharged by the expected amount and the onboard packs are full, then go ahead and jettison.
      - hef19898 3y ago
        You have to do that realibly, millions of times without failure, safely and without loosing redundancy. Flipping a relay is easy, doing in flight with one of most safety critical systems not so much. Man, I just hope all those aerospace companies YC is funding have founders with a much better understanding of these things...
        Johnny555 3y ago
        >Flipping a relay is easy, doing in flight with one of most safety critical systems not so much This system assumes an aircraft that is already battery powered and requires routinely detaching a very heavy piece of equipment in flight without causing undue risk to the aircraft and then autonomously flying that heavy battery pack over populated areas in airspace shared with other aircraft. The power control system for detaching battery pack is the least complicated part of this system.
        hef19898 3y ago
        Power decoupling is the only part that actually deserves any discussion at all, everything else is beyound rediculously laughable.
        Johnny555 3y ago
        So it sounds like you're agreeing with me -- the power management piece of this system is pretty much the only part that we understand how to do?
    - calamari4065 3y ago

dredmorbius 3y ago

The difference is that when you burn fuel, you burn fuel, and the mass exits the aircraft through the engine. When you discharge an electric cell, you're still carrying that electric cell with you. I suspect you're trying to express this and are fingering some other element of this concept as unrealistic, but that's not how your comment reads.

Johnny555 3y ago
I literally said that the depleted battery would be physically detached, I don't see how there is any other interpretation? I saw a concept once that had the plane drop the big battery after takeoff (maybe after reaching cruising altitude too) and let the battery fly back to the airport autonomously. Then it doesn't have to carry that dead weight for the entire trip. It's unrealistic because of all of the details in making a an autonomously flying battery pack that can detach from an aircraft in flight and do it with the kind of safety a civilian passenger aircraft demands.
- dredmorbius 3y ago
  That's clearer.
- notahacker 3y ago
  Apart from the detaching and flying a battery part, you've also got to seamlessly switch power source in midflight Otherwise you've depleted 25% of all your batteries and jettisoned a single battery pack, which (like the others) is 75% full. (That might of been a source of confusion).
  - Johnny555 3y ago
    That seems like the easiest part, flip the relays to disconnect the battery pack, evaluate remaining capacity and if the detachable pack is discharged by the expected amount and the onboard packs are full, then go ahead and jettison.
    - hef19898 3y ago
      You have to do that realibly, millions of times without failure, safely and without loosing redundancy. Flipping a relay is easy, doing in flight with one of most safety critical systems not so much. Man, I just hope all those aerospace companies YC is funding have founders with a much better understanding of these things...
      - Johnny555 3y ago
        >Flipping a relay is easy, doing in flight with one of most safety critical systems not so much This system assumes an aircraft that is already battery powered and requires routinely detaching a very heavy piece of equipment in flight without causing undue risk to the aircraft and then autonomously flying that heavy battery pack over populated areas in airspace shared with other aircraft. The power control system for detaching battery pack is the least complicated part of this system.
        hef19898 3y ago
        Power decoupling is the only part that actually deserves any discussion at all, everything else is beyound rediculously laughable.
        Johnny555 3y ago
        So it sounds like you're agreeing with me -- the power management piece of this system is pretty much the only part that we understand how to do?
  - calamari4065 3y ago