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>“It never made sense to me that it was possible to have a battery-powered car that could drive more than 300 miles but not have a battery-powered drone that co

>“It never made sense to me that it was possible to have a battery-powered car that could drive more than 300 miles but not have a battery-powered drone that could fly more than about 20 minutes,” he says. I don't see why...drone flight requires substantial power output to counteract gravity, which increases in proportion to the battery mass. Unlike a rolling vehicle This stinks of marketing gibberish.

perilunar 8y ago
Also very little opportunity for regenerative braking.
- dotancohen 8y ago
  While quickly descending use the motors as a generator via autorotation? I'm only joking, but there might in fact be practical application of the concept.
  - perilunar 8y ago
    I don't actually know if it's possible to autorotate a quadcopter. I imagine you would have very little control during the transition. Quadcopters don't fly very high anyway, so there's probably little to gain from it.
    - foobarbecue 8y ago
      ESC electronics usually doesn't support this, but I've wanted to try for many years.
    - thx11389793 8y ago
      autorotation requires control of blade pitch.
      - perilunar 8y ago
        It certainly does in helicopters, which have large, relatively heavy blades you really don’t want to stop turning. In a quadcopter the blades a small and light, so you could conceivably stop them and let them turn them in reverse as the airflow changes direction (from downwards to up through the blades). I think there would be real problem with control during the transition, and you’d need a lot of height to make it worthwhile.
- foobarbecue 8y ago
  Unless you use updrafts. Check out dynamic soaring. I have often thought about using updrafts above lava lakes and custom ESCs that can charge batteries to do quadcopter DS.
Grue3 8y ago
Having to constantly counteract gravity is just a limitation of this form of aircraft. If it was able to glide, then it would only need to spend energy to maintain height. Some birds can stay in the air for days without landing and they aren't exactly flying batteries.

perilunar 8y ago

Also very little opportunity for regenerative braking.

dotancohen 8y ago
While quickly descending use the motors as a generator via autorotation? I'm only joking, but there might in fact be practical application of the concept.
- perilunar 8y ago
  I don't actually know if it's possible to autorotate a quadcopter. I imagine you would have very little control during the transition. Quadcopters don't fly very high anyway, so there's probably little to gain from it.
  - foobarbecue 8y ago
    ESC electronics usually doesn't support this, but I've wanted to try for many years.
  - thx11389793 8y ago
    autorotation requires control of blade pitch.
    - perilunar 8y ago
      It certainly does in helicopters, which have large, relatively heavy blades you really don’t want to stop turning. In a quadcopter the blades a small and light, so you could conceivably stop them and let them turn them in reverse as the airflow changes direction (from downwards to up through the blades). I think there would be real problem with control during the transition, and you’d need a lot of height to make it worthwhile.
foobarbecue 8y ago
Unless you use updrafts. Check out dynamic soaring. I have often thought about using updrafts above lava lakes and custom ESCs that can charge batteries to do quadcopter DS.

Grue3 8y ago

Having to constantly counteract gravity is just a limitation of this form of aircraft. If it was able to glide, then it would only need to spend energy to maintain height. Some birds can stay in the air for days without landing and they aren't exactly flying batteries.