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Tiny, Morphing, Electricity-Stealing Spy Planes Developed
tkohler writes "The Air Force Research Lab is developing an Electric Motor-powered Micro Air Vehicle (MAV) that can 'harvest' energy when needed by attaching itself to a power line. It can also temporarily change its shape to look more like innocuous piece of trash hanging from the cable. For domestic spying, maybe it will morph into a pair of sneakers?"
It's not made yet. I doubt even a prototype has been made yet.
That's just a stupid urban legend. Shoes hanging from a powerline indicate nothing more than bored kids.
ZFS: because love is never having to say fsck
actually if the shoes are in a gang's color it is their way of claiming the corner, usually for drug sales. a nearby gang would throw up one black and one red shoe tied together because those were their colors. that way other gangs and independent pharmaceutical salespeople are forewarned that they shouldn't set up shop on that intersection. if they do, they are asking to get shot. some gangs use it to claim the turf in general, but mostly it is used to mark drug spots now.
i used to teach in the 'hood and was educated by my students about it. obviously this depends on the part of town we are talking about
Cute idea. What they're trying to do, it seems, is mooch a little power from the electrostatic field gradient around the wire. This is quite feasible if you have a wire with a few KV to ground. The classic demo is to light up a fluorescent lamp by placing it vertically below a high tension line. This works partly because air is not a perfect insulator. There's an electrical path to ground; it just has a high resistance.
If the thing lands on an 11KV power line that's 10m above ground, and has a conductive part that dips 10cm below the line, it should see a voltage difference of about 90 volts. You can't draw very much current before the voltage difference disappears, but you can draw a little.
It's also possible to extract some energy magnetically. See U.S. Patent #3,202,963, "Apparatus for Illuminating Power Lines". But that approach requires heavier parts than an electrostatic approach.