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Helicopter-Hovercraft hybrid

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Old 10th Apr 2007, 09:51
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Helicopter-Hovercraft hybrid






Geoff Hatton, a British engineer that previously worked on hovercraft designs, has designed an unmanned aerial vehicle that has attracted the interest of the US military and its very healthy budget allocation.
The design is based around the melding of a hovercraft with a helicopter, and manages to take some of the best characteristics of each. For one thing, the saucer shaped UAV can fly high in the air (unlike a hovercraft) but also doesn't have a large rotor blade (unlike a helicopter.)
The concept takes advantage of the "coanda effect" -- which says that a fluid will tend to stay attached to a convex surface -- with control surfaces at the base of the UFO-like vehicle used to alter the course of the UAV.
One of the main reasons that the military is interested is that the design means there's much less of a problem with collisions because the rotor isn't as big or as exposed on other reconnaissance vehicles, although Geoff points out that there are "a lot of prospects besides the military": because civilians can be klutzes when it comes to unmanned aerial vehicles too.
The 68-year-old has won a contract with the US government for his 3ft-wide contraption, a cross between a hovercraft and a helicopter. It is being considered for surveillance sorties.
"Unlike a helicopter, though, this is aerodynamically neutral and you can bump into walls and not smash the rotor,' said the inventor. "And, unlike a hovercraft, you can fly it as high as you want."
The dome-shaped object is powered by an electricity-driven propeller on top that pushes air over the outer surfaces, and has controllable flaps.
The device, which was rejected by the Ministry of Defence, was funded partly by a £43,000 development grant from the Department of Trade and Industry five years ago.
The Americans are convinced that it has potential.
"It's a unique approach which lends itself to a surveillance platform,' said Sal Gomez, of the US army's International Co-operative Programs centre. "It could be useful in urban areas because if it bumped into walls it could recover. This is just the earliest of days, like the Wright Brothers."
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Old 10th Apr 2007, 10:03
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Autorotational capabilities of a brick. Limits its use somewhat to a desert.
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Old 10th Apr 2007, 10:20
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Letsby, that's probably just the sort of attitude that allowed the MOD to pass over a promising piece of technology and let the US DoD have it. Sadly all too typical of Britain over the last few decades - prototype doesn't work perfectly so bin it, why should we bother wasting money on development. Why indeed. How the hell we ever developed something like the Harrier is is beyond me - and beyond us all if it were to happen again today.

But tell me, Letsby, why would autorotation be even slightly important in a military surveillance vehicle? These things by their very nature are cheap and expendable, and if it were important not to bang the enemy's heads if it fell from the sky surely a piece of sorbo or a parachute would do the trick?

I bet the poor inventor is pulling his hair out.

Shame shame shame.
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Old 10th Apr 2007, 11:23
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Coanda effect flying machines are not new, and have always had the problem of the coanda skirt being heavier than an equivalent rotor. The disk loading is also inherently high which, as Letsby comments, means it can never be considered for piloting. That said this is a good application of the technology, and i wish Geoff Hatton well.

I'm almost ashamed that i agree with you, Agaricus bisporus. When working abroad i used to jokingly refer to UK as the "Land of Dispair and Apathy", but the joke wears thin after you see innovator after innovator crushed to favour the finance sector. I would like to become one of those innovators at some point, but will probably try to avoid any funding within the UK.

Mart

Last edited by Graviman; 13th Apr 2007 at 21:32. Reason: Last part was just a whinge anyhow.
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Old 10th Apr 2007, 14:15
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Typical PR bumf, in that it infers the unique virtue of protecting its rotor comes at no cost in other mission attributes.

The question was never asked by our astute press people: "What does it give up to gain this feature?" (nor was this asked by the ppruners who fell in love with it!)

I would guess the power needs (and fuel requirements in a hover) are probably twice that of a helo, so the question, fully phrased, is:

"Do you want half the payload and half the radius of action as a trade-off for the ability to bump into walls?"

I'd give my eye teeth (whatever they are) for a reporter who bothered to ask simple questions. That being said, the concept is interesting. It appears that the bowl below "shapes" the air plume to make the air spread out, increasing efficiency because it reduces disk loading, since the bigger the fan of air, the less the power required.

Last edited by NickLappos; 10th Apr 2007 at 14:58.
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Old 10th Apr 2007, 15:08
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Agree with Nick about this invention.
But I think the idea of a "Helicopter/Hovercraft Hybrid" makes sense, for surface tasks not requiring an expensive conventional helicopter.
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Old 10th Apr 2007, 15:12
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"Typical PR bumf, in that it infers......"

Why can't you just cut the guy some slack? He is not inferring anything about mission attributes or technical mumbo-jumbo, he just seems to be an engineer who has put some thought into a fairly unique flying machine and has made the comittment to see it through.

I think he deserves copious amounts of respect rather than any form of dismissal.
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Old 10th Apr 2007, 15:43
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I can see how this new vehicle could have uses in the UAV mission being considered and used by the US Military as we speak. It may be limited in size and lifting capability but having the shrouded rotor should make it useful for use in an urban environment.

It sure beats the Osprey concept in my view. One thing is it will not cost billions of dollars and human lives as does the Osprey.

You reckon some folks said something similar about Igor in the early days of his helicopter experiments?
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Old 10th Apr 2007, 18:08
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Hi all,
inventions makes the world go round.
Still, the benefit isn yet very clear, because there are already drones available, which 1st, don't bump into walls, because they are stable in the air (inbuild gyro) and 2nd - offer already various payload variations.
Take a look at http://www.airrobot.com/


Greetings "Flying Bull"

Scary to think about ground forces beeing interested in this product - instead of a helicopter :-(
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Old 10th Apr 2007, 22:42
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So we're all agreed then... Only useful over the desert errr where there aren't any walls to bump into anyway Nice. Glad to see the good old USofA have got billions to pump into this sort of thing, we've just blown all of our dosh on Eurofighter.
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