USAF Spy planes to recharge by power lines

19 Dec 2007, 1944 hrs IST,ANI

AFRL wanted to operate extended surveillance missions using remote-controlled planes with a wingspan of about a metre, but had been struggling to find a way to refuel to extend the plane's limited flight duration.

However, it seems that with the new idea of developing a spy plane, which could ‘harvest’ energy when needed by attaching itself to a power line, has the ability to solve the problem.

The aircraft would even have the ability to transform into inconspicuous objects, like an innocuous piece of trash hanging from the cable.

AFRL's first plan 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.

Also, to avoid suspicion, the plane would need to collapse its wings and hang limply on the cable like a piece of wind-blown detritus. Much of the ‘morphing’ technology to perform this has already been developed by DARPA, the Pentagon's research division.

Technologies developed in that program include carbon composite ‘sliding skins’, which enable fuselages to change shape, and telescopic wings that allow lift to be boosted in seconds by boosting a wing's surface area.

However, Zac Richardson, a power-line engineer with National Grid in the UK, has warned that the notion of landing on a power line is riddled with challenges.

Richardson said that if the MAV contacts an 11-kilovolt local power line, it could short circuit two conductors, causing an automatic disconnection of the very power the plane seeks. And, on a 400-kilovolt inter-city power line, it risks discharging sparks.

"It will hang there fizzing and banging and giving its position away anyway," New Scientist quoted Richardson, as saying.

Ian Fells, an expert in electricity transmission based in Newcastle, UK, said: "Even kites falling across power lines cause breakdowns. It's an utterly bizarre idea to try to land a plane on one."

Despite these challenges, the AFRL is planning on conducting test flights in 2008.

http://timesofindia.indiatimes.com/Spy_planes_to_recharge_by_power_lines/articleshow/2635356.cms