3 ms·

I'd love to see a future where part of a plane's battery pack is a detachable drone that could fly back right after takeoff (most taxing on energy use) and thus

by gibolt 6y ago

I'd love to see a future where part of a plane's battery pack is a detachable drone that could fly back right after takeoff (most taxing on energy use) and thus decrease the weight of the plane. You could also have battery swaps during flight as they pass over drone battery depots. Sounds crazy. Might not be worth the gains for the complexity, but could be worth it across a whole fleet. Microwave laser groundstations (or solar satellites) could come first, removing much of the battery requirement.

tengbretson 6y ago
Hah, now you've got me imagining a gentle rain of 18650 batteries following a plane as it travels across the sky.
- gibolt 6y ago
  Yes, gentle :D
mikeyouse 6y ago
Seems like you'd be better off with a ground-based catapult system to get the plane up to speed and in the air where the on-board motors could take over.
- gibolt 6y ago
  If these are passenger aircraft, that probably wouldn't fly
  - microcolonel 6y ago
    > If these are passenger aircraft, that probably wouldn't fly Well, it doesn't need to have the same rate of acceleration as a carrier's, but honestly it just doesn't make sense in general.
    - mikeyouse 6y ago
      Right -- you could use the full length of an existing runway to have a gentle acceleration , bt I'd argue this makes a lot more sense than some sort of drone delivered jettisoned/retrieved battery if your goal is to reduce on-board energy expended for takeoff. Much less complex and the wear parts would be fixed at the airport rather than on every single airplane.
      - microcolonel 6y ago
        > I'd argue this makes a lot more sense than some sort of drone delivered jettisoned/retrieved battery.. Oh absolutely, it compares favourably to one of the most asinine first-pass approaches to this problem I've ever seen, heheh. The real solution is to find a way to produce good liquid fuel from a cheap and abundant source of overprovisioned baseline power (maybe make hydrogen† from your nuclear power in off-peak hours). Batteries are mostly composed of matrix, so even if you could extract energy as efficiently from the non-matrix materials in the battery as you can from hydrocarbon combustion, you would still be lugging around all that matrix. † Yes, I get that it's 3 times less energy dense than good hydrocarbons, but it's a start when compared to batteries.
    - K0balt 6y ago
      Might make more sense that you suspect. An airport designed to land uphill and takeoff downhill actually makes huge a difference in operating costs for heavy aircraft. Takeoff and initial climb are huge fuel burners.
- klyrs 6y ago
  Catapult really paints the wrong picture... but if you say ballista and actually mean a maglev rail accelerator then I'm down
usrusr 6y ago
Another crackpot idea: Instead of a catapult or a flying battery pack, go for a tethered launch. The plane taxis onto a platform that is actually a powerful "cable laying UAV" with powerful ducted fans for propulsion and some lift and two big powered spools of copper as heavy as it can carry. The platform arrests the plane's main undercarriage, connects power lines to the plane and raises itself on its own set of wheels. They accelerate together, leave the ground together, all while the powered spools are unrolling the wires to the ground station exactly as fast as needed to avoid mechanical drag (the wires are effectively in free-fall, perhaps issues with the cable landing could be evaded by sending up a chain of "cable carrying (T)UAVs" that take the role of virtual poles). In time before the spools run out, the platform disconnects from the plane slows down the spools so that the inertia and main motors of the platform start pulling on the wires, then reels itself back in while it maneuvers to a point above the base station, finishing the circle with a tail-landing followed by dropping into "platform" position controlled by its secondary fans. Meanwhile, the plane flies of into the sunset on a fresh set of batteries. But the battery tender UAV actually sounds far more practical, I guess I just like ideas involving tethered UAV. (and somehow I feel almost entitled do spew out the most improbable ideas, since seeing footage of the successful dual suicide burns of the Falcon Heavy boosters - if that's possible, why isn't everything else as well?)

by gibolt 6y ago

tengbretson 6y ago

Hah, now you've got me imagining a gentle rain of 18650 batteries following a plane as it travels across the sky.

gibolt 6y ago
Yes, gentle :D

mikeyouse 6y ago

Seems like you'd be better off with a ground-based catapult system to get the plane up to speed and in the air where the on-board motors could take over.

gibolt 6y ago
If these are passenger aircraft, that probably wouldn't fly
- microcolonel 6y ago
  > If these are passenger aircraft, that probably wouldn't fly Well, it doesn't need to have the same rate of acceleration as a carrier's, but honestly it just doesn't make sense in general.
  - mikeyouse 6y ago
    Right -- you could use the full length of an existing runway to have a gentle acceleration , bt I'd argue this makes a lot more sense than some sort of drone delivered jettisoned/retrieved battery if your goal is to reduce on-board energy expended for takeoff. Much less complex and the wear parts would be fixed at the airport rather than on every single airplane.
    - microcolonel 6y ago
      > I'd argue this makes a lot more sense than some sort of drone delivered jettisoned/retrieved battery.. Oh absolutely, it compares favourably to one of the most asinine first-pass approaches to this problem I've ever seen, heheh. The real solution is to find a way to produce good liquid fuel from a cheap and abundant source of overprovisioned baseline power (maybe make hydrogen† from your nuclear power in off-peak hours). Batteries are mostly composed of matrix, so even if you could extract energy as efficiently from the non-matrix materials in the battery as you can from hydrocarbon combustion, you would still be lugging around all that matrix. † Yes, I get that it's 3 times less energy dense than good hydrocarbons, but it's a start when compared to batteries.
  - K0balt 6y ago
    Might make more sense that you suspect. An airport designed to land uphill and takeoff downhill actually makes huge a difference in operating costs for heavy aircraft. Takeoff and initial climb are huge fuel burners.
klyrs 6y ago
Catapult really paints the wrong picture... but if you say ballista and actually mean a maglev rail accelerator then I'm down

usrusr 6y ago

Another crackpot idea: Instead of a catapult or a flying battery pack, go for a tethered launch. The plane taxis onto a platform that is actually a powerful "cable laying UAV" with powerful ducted fans for propulsion and some lift and two big powered spools of copper as heavy as it can carry. The platform arrests the plane's main undercarriage, connects power lines to the plane and raises itself on its own set of wheels. They accelerate together, leave the ground together, all while the powered spools are unrolling the wires to the ground station exactly as fast as needed to avoid mechanical drag (the wires are effectively in free-fall, perhaps issues with the cable landing could be evaded by sending up a chain of "cable carrying (T)UAVs" that take the role of virtual poles). In time before the spools run out, the platform disconnects from the plane slows down the spools so that the inertia and main motors of the platform start pulling on the wires, then reels itself back in while it maneuvers to a point above the base station, finishing the circle with a tail-landing followed by dropping into "platform" position controlled by its secondary fans. Meanwhile, the plane flies of into the sunset on a fresh set of batteries. But the battery tender UAV actually sounds far more practical, I guess I just like ideas involving tethered UAV. (and somehow I feel almost entitled do spew out the most improbable ideas, since seeing footage of the successful dual suicide burns of the Falcon Heavy boosters - if that's possible, why isn't everything else as well?)