Print 14 comment(s) - last by Calin.. on Dec 1 at 5:17 AM

U.S. military hopes to make spy planes greener, but several hurdles must be overcome

Unmanned robotic spy planes are now going green as researchers hope to develop aircraft able to fly longer while also conducting surveillance with less threat of detection due to engine noise.

Most drones today use internal combustion engines that are extremely loud, which forces officials to fly them at higher altitudes during missions.

"Think about lawnmowers or chainsaws -- they're really loud," Naval Research Lab researcher Karen Swider-Lyons told LiveScience during a recent interview.  "It's hard to spy on people when they know you're there, so you had to fly them at high altitudes to keep them from being heard."

The Office of Naval Research said spy planes powered by electric engines are available, but they have shorter estimated flight times than aircraft powered by internal combustion engines.

To help fill a void in next-gen technology, the "Ion Tiger" UAV is powered by hydrogen fuel cells.  The engines can run quieter than a regular engine, while also being twice as efficient, offering an appealing alternative as the USAF increases the use of spy planes.  

During testing in October, Ion Tiger flew 23 hours and 17 minutes consecutively, though that number was recently topped while flying over the "Aberdeen Proving Ground."  The 37-pound craft flew for 26 hours and 1 minute.

The military has announced different ways it looks to go green, ranging from hybrid Humvees to greener Navy ships -- but this is the first significant proof showing a UAV successfully powered by alternative energy.

The newer drones could also fly civilian routes to observe natural disasters, track storms, or provide surveillance, military experts said.

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Am I missing the obvious?
By Amiga500 on 11/30/2009 8:42:43 AM , Rating: 5
Ducted fan, mini-turbine engine and noise is sorted.

If they want more range, then scale up the wing and get more fuel in there.

Simple, cost effective and do-able within a year.

RE: Am I missing the obvious?
By R6Raven on 11/30/2009 8:45:39 AM , Rating: 5
Exactly. However, that would be a conservation of tax-payer dollars, and we both know there's no room for that.

RE: Am I missing the obvious?
By FastEddieLB on 12/1/2009 4:30:27 AM , Rating: 2
Of course not, because then they'd have to give out a tax refund. Gotta keep congress in their golden parachutes ya know.

RE: Am I missing the obvious?
By Calin on 12/1/2009 5:13:05 AM , Rating: 2
Scale up the wing means scale up the model. So, instead of being able to be launched by hand and retrieved by a net, it means needing a car-borne catapult and a landing "strip".

How could you get up the mileage on your car? By pulling a trailer loaded with fuel. However, this isn't what you would always want

Hydrogen fuel cell.. or.. blimp?
By FishTankX on 11/30/2009 9:20:15 AM , Rating: 2
Wouldn't it be possible to create a UAV that would be powered by a transparent hydrogen lifting cell, which it could draw fuel from, and gradually retract as the fuel depletes? I imagine a 5000 liter lifting cell would provide quite a bit of energy, as well as ease energy requirements for much of the intended mission. Very good for loiter.

Make it even more interesting by giving it solar cells and the ability to replenish it's lift cell with hydrogen generated from electrolysis from the solar cells, and the water generated by the fuel cell. A sort of very large, lifting battery of sorts. It's a UAV, probably shouldn't care much if it blows up. Good loiter, too.

RE: Hydrogen fuel cell.. or.. blimp?
By JediJeb on 11/30/2009 11:24:14 AM , Rating: 2
If it uses the Hydrogen for the fuel sell then it will lose lift as it uses it up. If you add more Hydrogen before takeoff then you increase lift and may need more water as ballast, but I guess you could use solar to generate Hydrogen from the ballast as you go. If you can work in a way to constantly recycle the water from the fuel cell back into the fuel cell they you would be set, but it would take a lot of solar energy to do it. Best bet would be hydrogen cell for lift, and solar to run the electronics with limited battery or fuel cell for nighttime duty.

RE: Hydrogen fuel cell.. or.. blimp?
By foolsgambit11 on 11/30/2009 10:45:33 PM , Rating: 2
Totally ignoring the aerodynamics of towing a bag full of hydrogen....

RE: Hydrogen fuel cell.. or.. blimp?
By ViroMan on 11/30/2009 11:51:33 PM , Rating: 2
Towing? you mean being towed by the wind in the air right?

No mater how clear the material is, it will still likely reflect/refract light that will be detectable to anyone watching.

Im sure they KNOW we use UAV's by now. So its not too far fetched to think that they have someone watching the skys all the time, or watching for certain frequencies (UAV's radio control) to get used.

RE: Hydrogen fuel cell.. or.. blimp?
By Calin on 12/1/2009 5:17:46 AM , Rating: 2
What about strong winds? This could force you to use much bigger engines to stay on course.

Call me old fashioned but
By corduroygt on 11/30/2009 11:27:31 AM , Rating: 2
The only green I want to see in the military is camouflage.
Everything else should be geared towards improved performance/lower cost/higher range/more stealth etc. You know, the stuff that helps win battles.

RE: Call me old fashioned but
By Smartless on 11/30/2009 1:51:01 PM , Rating: 2
Well, going green could involve half of what you said like higher range and lower cost. Heck keeping a spy plane in the air for 24 hours at low altitude and fairly quiet could have prevented a few ambushes in Afghanistan. Hey as long as Congress likes it.

RE: Call me old fashioned but
By corduroygt on 11/30/2009 3:20:04 PM , Rating: 2
I agree, but the priority should be better performance with green being the side effect, NOT the other way around.
That's what I was trying to convey in my first post.

RE: Call me old fashioned but
By smitty3268 on 11/30/2009 4:51:50 PM , Rating: 2
One of the other benefits of "going green" would be reduced supply lines. Anything that makes the fighting forces more self-sufficient also makes them much more agile. But I agree, performance should be priority #1.

Nothing to do with green
By nafhan on 11/30/2009 9:31:10 AM , Rating: 5
-able to fly longer
-less threat of detection due to engine noise
-subsequently, lower altitudes without being detected

Those are your reasons right there. The "green" angle is just to help sell it to Congress.

"If a man really wants to make a million dollars, the best way would be to start his own religion." -- Scientology founder L. Ron. Hubbard
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