7 ms·

I always wondered if this could work, that is if it'd be more energy efficient that using fuel/batteries to reach cruising altitude: - use lighter than air ba

by psadri 4y ago

I always wondered if this could work, that is if it'd be more energy efficient that using fuel/batteries to reach cruising altitude: - use lighter than air balloon to life an aircraft to cruising altitude - transition to powered flight while collapsing the balloon (by compressing the gas into liquid form?). Or maybe detaching from it? - cruise - at destination, glide towards touch down?

pqdbr 4y ago
Those are crazy ideas. I love them. Anywhere they have been experimented with before?
- psadri 4y ago
  Looks like quite a few companies worked on the idea for orbital launches -- lift a rocket with a balloon and then launch from a high altitude.
  - 6stringmerc 4y ago
    There is a lot of talk about horizontal launch for spacecraft - I’m pretty sure steam catapults and aircraft designed to use them could change things as well.
  - Ekaros 4y ago
    Rocketry really isn't about height but speed. And balloons don't actually help so much with that. At least if you want to stay up there once the lift is gone.
    - psadri 4y ago
      Most of a rocket's weight is fuel. Ironically, most of that fuel is needed to lift the rest of the fuel from ground level to some altitude A, then the remaining fuel is used to get to A', and so on. If you could first lift the rocket to a high altitude, you could get away with far less fuel. The smaller mass would mean faster acceleration (think a rocket fired from a jet fighter). note: I'm not a rocket scientist or physicist :-)
lmm 4y ago
> use lighter than air balloon to life an aircraft to cruising altitude Interesting thought, but that would mean you've got aircraft ascending slowly right through the entire airspace with limited control. Difficult to imagine it would be workable at busy airports. > Or maybe detaching from it? Consuming a balloon's worth of helium every flight is a non-starter, and hydrogen is probably unacceptable to passengers. Landing a balloon is also not cheap or easy, even without passengers. > at destination, glide towards touch down? Almost all planes essentially do this already, they'll reduce thrust and start descending a long way out.

by psadri 4y ago

pqdbr 4y ago

Those are crazy ideas. I love them. Anywhere they have been experimented with before?

psadri 4y ago
Looks like quite a few companies worked on the idea for orbital launches -- lift a rocket with a balloon and then launch from a high altitude.
- 6stringmerc 4y ago
  There is a lot of talk about horizontal launch for spacecraft - I’m pretty sure steam catapults and aircraft designed to use them could change things as well.
- Ekaros 4y ago
  Rocketry really isn't about height but speed. And balloons don't actually help so much with that. At least if you want to stay up there once the lift is gone.
  - psadri 4y ago
    Most of a rocket's weight is fuel. Ironically, most of that fuel is needed to lift the rest of the fuel from ground level to some altitude A, then the remaining fuel is used to get to A', and so on. If you could first lift the rocket to a high altitude, you could get away with far less fuel. The smaller mass would mean faster acceleration (think a rocket fired from a jet fighter). note: I'm not a rocket scientist or physicist :-)

lmm 4y ago

> use lighter than air balloon to life an aircraft to cruising altitude Interesting thought, but that would mean you've got aircraft ascending slowly right through the entire airspace with limited control. Difficult to imagine it would be workable at busy airports. > Or maybe detaching from it? Consuming a balloon's worth of helium every flight is a non-starter, and hydrogen is probably unacceptable to passengers. Landing a balloon is also not cheap or easy, even without passengers. > at destination, glide towards touch down? Almost all planes essentially do this already, they'll reduce thrust and start descending a long way out.