Comment by mikrl
21 hours ago
If this works via induction could you even eliminate the need for the drones to land?
Assuming flight conditions are good, there would be a region around the wire (line of charge) with an electric/magnetic field that the drones could use, any shielding notwithstanding.
Coupling falls off rapidly with distance. It's why a thick enough phone case will interfere with magnetic charging, and that's only on the scale of a few millimeters.
Drones consume a lot of power while in flight. You can get a little bit of power out of powerlines standing underneath them with some tricks, but it's not enough to keep a drone in flight. At least not without something prohibitively large to couple to the line.
It's also risky to hover near a stationary object because the longer you hover, the more you're exposed to the risk of a wind gust knocking you into the nearby obstacle.
iirc efficiency loss in wireless energy transmission is exponential? someone correct me. But basically after just a few mm the losses are so great that the amount of electricity needed becomes ridiculously wasteful.
to power a running drone at more than a few inches would be just...a lot.
Inverse square, so each time the distance doubles the power density drops by a factor of four.
That was my thought as well...I suppose there may be something I am not thinking of. Perhaps they get more total energy if they "perch" on the tower.
My gut says there's something like an inverse-square law that governs how far away they can effectively charge.
It’s exactly the inverse square law.
You get a million times more power if you can put a coil 1mm away from the wire than if you hover 1 meter away.
It's actually an inverse first power law, assuming that the distance of the drone from the wire is much less than the length of the wire. The inverse square law applies only to a point source of electrical energy, to a sphere, or to an object whose largest dimension is much less than the distance to the drone.
Yes, feels like perching via some insulated "feet" and only using energy for stabilisation (as opposed to flight) would allow the drone to get very cloe (and suck much more power) from the line.
It'll definitely charge faster, if only because it's drawing less power to stay up and getting closer. The only question is, is it like 10% or 100% faster?
Drones consume something like 100W to stay in the air (ballpark, of course), so they'd probably never charge if they had to hover.
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