The next time you see something flapping in the breeze on an
overhead power line, squint a little harder. It may not be a
plastic bag or the remnants of a party balloon, but a tiny spy
plane stealing power from the line to recharge its batteries.
The idea comes from the US Air Force Research Lab (AFRL) in
Dayton, Ohio, US, which wants to operate extended surveillance
missions using remote-controlled planes with a wingspan of about
a metre, but has been struggling to find a way to refuel to
extend the plane's limited flight duration. So the AFRL is
developing an electric motor-powered micro air vehicle (MAV)
that can "harvest" energy when needed by attaching itself to a
power line. It could even temporarily change its shape to look
more like innocuous piece of trash hanging from the cable.
AFRL's initial aim is to work out how to make a MAV flying at 74
kilometres per hour latch onto a power line without destroying
itself or the line. In addition, so as not to arouse suspicion,
AFRL says the spy plane will nee