Combined Hovercraft and Helicopter 254
An anonymous reader writes "Has British engineer Geoff Hatton brought us the best of two worlds with his UFO-looking machine? The US military thinks so and are investing in it. The design is sturdy (as opposed to a helicopter) and can fly high (as opposed to a hovercraft). It is based on the Coanda Effect."
sturdy? as opposed to a helicopter? (Score:4, Insightful)
Saying "The design is sturdy (as opposed to a helicopter)" is really quite a statement since the design is not in service.
Seems pretty cool though.
Re:sturdy? as opposed to a helicopter? (Score:5, Insightful)
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Re:sturdy? as opposed to a helicopter? (Score:5, Informative)
They won't be much larger, or made out of much more durable materials (they can be flexible) because they are planning to use them as UAVs and not as manned aircraft, at least for the time being. If you RTFA they specifically talk about the design's suitability for this purpose in light of its ability to survive collisions with walls.
I'm afraid I'm going to dream of manhacks tonight...
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Re:sturdy? as opposed to a helicopter? (Score:5, Informative)
I don't think that's what he's referring to at all. Helicopters are very unstable machines, especially in hover mode, which is arguably the most important and most distinguishing feature of a helicopter. A helicopter requires hundreds of very precise control inputs a minute to remain in a hover. If you change one of the variables, you pretty much have to change all of the rest. For example, if you adjust the cyclic, you have to adjust your engine's torque and collective a tiny amount so you don't fall out of the sky, or alternatively, go flying up too fast, and you'll also have to nudge the tail rotor to account for the increased torque form the main rotor. You can think of it as a loop in a computer program that operates very quickly.
It looks like this guy's hovering craft aims to make the most advantageous feature of a helicopter much, much easier to preform, and hence the vehicle is "more stable" than a helicopter. It's probably more sturdy, too, but that's a side effect of not having blades swinging around in an arc that is considerably larger than the aircraft.
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As for the stability of helicopters, if you look at the designs in the 50's and 60s, stability was a big goal. Look at Stanley Hiller's demonstration of hands off hovering of his
Re:sturdy? as opposed to a helicopter? (Score:5, Informative)
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Yes, you probably were.
Unless equally sized bits break off of every blade or a *very* small piece breaks off a blade, the helicopter is almost sure to immediately literally explode from the created imbalance. And that's not a joke.
Many RC-Helicopter pilots know this from own experience -- a loud bang and the helicopter rains down in pieces (and those blades onl
Re:sturdy? as opposed to a helicopter? (Score:5, Informative)
Re:sturdy? as opposed to a helicopter? (Score:5, Interesting)
The second is that it would avoid a problem which helecopters face when trying to hover out of ground effect. When more than about a rotor's diameter above the ground, the downward moving air starts to circulate down, out, up, and back into the rotor. The air moves in a circular pattern through the rotor, around, and back through the rotor again. This creates a downdraft from the perspective of the helecopter. Adding more power doesn't always help, because it just makes the air move in a circular pattern faster. The result is that the helecopter sinks when trying to hover at altitude.
If you observe helecopters hovering at altitude, you'll notice that they aren't actually hovering. They're moving forward very slowly. That's the only way to avoid that problem. You have to keep moving a little bit so you stay out of the circular rotation of air that you create behind your helecopter. If you stop completely, you're in the circular pattern and you sink unless you've got some enormous power source like a jet engine.
When you're in ground effect, the ground itself disrupts the circular movement of the air and limits how fast it can move in a circular motion. It also makes it turbulent as it deflects off the ground. The result is that you don't get a well-formed column of downward moving air that your helecopter is sitting in, thus you can efficiently hover without moving at all when you are fairly close to the ground or some other air-disrupting object like a building that you're carrying materials up to.
I would not be surprised if this device had some advantages over regular helecopters when it comes to hovering out of ground effect.
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> hovered absolutely still (+/- 6-12") for over 5 minutes while a tech harnessed to the
> side and hanging down attaches the insulator on top of the tower in 30 mph wind.
Hovering with respect to the ground in a 30mph wind is the same as moving 30mph in still air.
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Maybe they meant "stable"? That doesn't really make a lot of sense either. . . .
Sturdy vs surveilance helicopters, perhaps (Score:2)
Re:Sturdy vs surveilance helicopters, perhaps (Score:4, Funny)
Re:sturdy? as opposed to a helicopter? (Score:5, Interesting)
I talked to a air-rescue helicopter pilot once and he told me they have helicopters in service that are 35+ years old, but the only original parts in them are their skids.
Maintenance? (Score:2)
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Re:Maintenance? (Score:4, Informative)
As an aside, I'm not sure why using the Coanada effect is better than just building a ducted fan with internal control surfaces. Putting that big blockage in your airflow just seems like it's going to sap power from your engine.
Balance (Score:2)
Putting that big blockage in your airflow just seems like it's going to sap power from your engine.
Agreed, however I think the possible advantage is that you can hang something directly in the center underneath, thus maintaining the center of gravity inline with the fan's center point, rather than trying to balance the payload out when placing it outside the diameter of the fan. That's a big plus. The Coanda effect just allows for them to shed the weight of the ducting by not having to worry about totally enclosing the air flow.
Ducted fans (Score:2)
There were also devices with a single internal ducted fan featured on slashdot a while back. These are simple to control, but only if the center of
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Fluids is a tricky subject, and not just grammatically. So long as the force doing the redirecting of the flow is everywhere normal to the direction of the flow there is no power expended in the process of redirection. This is not quite the case in the Coaanda effect, which seems to be mediated by frictional effects, but one of the startling things about it is that the normal forces are much larger than the frictional forces, so you do get substantial redirection with very small losses.
Better structure for lift and control (Score:3, Informative)
It also causes the lift (and thrust) to appear distributed over the surface of the fuselage (except for the very center), where it can be easily transferred to support the payload.
With a helicopter lift appears on the rotor. It must first be focussed on the rotor shaft, then passed through a bearing, and
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It may be stable without any control inputs. Internal-fan lifting bodies tend to precess and flip without corrective control.
It may be resistant to bumping walls. The air flowing over the surface may push it away from obstructions, making it valuable for maneuvering in tight spaces.
I suspect it is less maneuverable, but more stable, than a contained propeller VTOL. This is an advantage in urban situations. But it's pure speculat
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But my curiosity is in energy efficiancy vs. a heli style machine. Yeah, it might be an order of magnitude safer, but if it costs twice as much to run, how much of a help can it be?
I was looking at the video and for secret surveilence I think this wouldn't work. It's WAY too loud. It would be good for commercial arial shots though.
I saw many things in that video alone that made me wonder...
1. Why square (ish?) why not use a
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# 3. they have self powered models.
2. it appears to fall flat, w/ the flaps extending
1. Square, Circle, Rectangle. Shape matters little. 1.a No one has a model w/ the stabilizer flaps moving (that I saw) 1.a.2 There is a proposal to use flapless by using some kind of plasma fluid. That looks interesting indeed!
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I have a AirHogs Reflex that I am going to try this effect with! I had the greatest Idea of putting the top of a frappaccino cup. It's a Dome shapped piece of thin plastic that would fit under the rotors. I'll let you know more when I get it together!
Re:Maintenance? (Score:5, Informative)
"'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.
Geoff's Flying Saucers - the original name for his GFS Projects company - are based on an aerodynamic principle that has been around for nearly 100 years.
Known as the Coanda Effect, after a Romanian jet-engine pioneer, the principle is today used primarily in helicopters that have no tail rotors."
Sounds to me like it's even less complicated than a traditional helicopter. The blades in a traditional helicopter go through some incredibly complex motion. From the pictures in TFA, it looks to me like this is a simple propeller. Rather than relying on complicated mechanisms on the blades, it exploits the properties of the working fluid (air in this case). The adjustable flaps over that outer surface look simple enough.
Seems to me like a lot less complex, mechanically, than the helicopters we've been deploying to wars for decades.
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Actually, half the tags come across as heavily opinionated comments. Questions are answered "yes" or "no" or often, both. A product that might not work quite right or a company that gets its come-uppens gets tagged "haha".
Ya, these are really going to help anyone search.
Penguin on a treadmill (Score:4, Funny)
Excellent! (Score:5, Funny)
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Revenge probing?
Best link in the article (Score:2)
Now we see Linus' master plan. Apparently he didn't get enough karma for Linux.
Coand effect (Score:3, Insightful)
If air didn't stick to smooth leading edges, aircraft could never get enough L/D to fly subsonic.
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Re:Coand effect (Score:5, Interesting)
My one question (Score:2, Interesting)
I'm curious whether the flying saucer would be stable and not spin around. Helicopters have rear rotors so they can counteract the spin forces induced by the main rotor. Other helicopters [wikipedia.org] have two rotor blades on top of each other, one spinning one way, the other spinning the other way.
Without a design that counteracts the torque caused by the only rotor, what is it that will prevent the UFO thing from spinning around like crazy?
Re:My one question (Score:5, Informative)
Note the scoops on the sides. They're all directing the airflow clockwise (as seen from top). If your rotor is also spinning clockwise (as seen from top), the airframe will be torqued counterclockwise, and those little scoops will counter the torque.
Just my guess.
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From what I can tell from the picture, a small amount of the downward thrust is directed in the opposite direction of the rotation, producing the necessary counter torque.
Look at those curved fins on the sides. (Score:3, Informative)
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There's a little goblin inside who spins it the other way.
Not funny, not informative, but at least it's not another dupe.
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There are a few radio-control helicopters that have a separate motor for the tail rotor and vary its speed for control, simply for the sake of mechanical simplicity.
UK definately dropped the sauser on this one... (Score:2)
This is an excellent idea. Almost one of those head slapping "why didn't I think of that?" type ideas.
I could see these replacing many unmanned aerial recon aircraft in urban and other areas where there is potential for the craft to bump into objects. Hell, with a bit of inlet cowling to prevent debris from hitting the propeller, I would suspect this thing could be used in wooded areas like dense jungles where typical surveillance craft can only use infrared.
Definitely a marketable ide
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Hmmm... (Score:4, Funny)
Amazing opportunity... (Score:4, Funny)
Re:Amazing opportunity... (Score:4, Funny)
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seems inefficient? (Score:3, Interesting)
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As to how efficient this is. I don't know it may have a lot of advantages at low Reynolds number but totally fall apart at higher ones.
In other words it may be the bee's knees for a small drone but fail totally for a replacement for a Blackhawk.
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I'd need to play with one to see for sure, but I think the key feature here is the anti-torque stator vanes on the shell. Otherwise, my intuition tells me that a direct-lift system would be more "efficient" (in terms of pounds of lift per watt of electrical power).
Or I could be mistaken. Low-speed aerodynamics is a very tricky business.
Re:seems inefficient? (Score:4, Interesting)
This craft moves a smaller amount of air across it's surface, like the wing of an airplane, the way the air flows across it's surface creates the low pressure zone necessary to create lift.
The method you discuss, works well in situations where the rotors are very large in relation to the body of the craft, while this method works even when the rotors are much smaller in relation.
I am sure someone with a little more understanding of the physics involved could improve upon what I just said, but I'm pretty sure this is the way it works.
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What makes it better, or more news-worthy, than for example this design;
http://www.globalsecurity.org/intell/systems/image s/cypher-pic2.jpg [globalsecurity.org]
Could be the whole point of the article is the humane angle; that an old guy built it in his shed. Ho
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Consider the 2 designs, and think about where you would place the payload, and how much of it you can have.
In your link, the craft needs the central area clear of obstacles to allow airflow, leaving only the perimeter available for payload. In the article's craft, the air is directed around the perimeter of the craft, leaving the central area available for payload.
From the video, it appears (Score:2, Funny)
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If the military threw money and talent at it, i'm sure it could be made very quiet.
What to call it? (Score:3, Funny)
Why is this a great idea? (Score:2)
This thing has to carry heavy batteries or fuel, limiting its range. And it's ungodly loud. A small dirigible is silent and I imagine you can make one pretty small given how lightweight today's surveillance tech is.
Seems like the only thing this might have over a blimp is speed. But if it's speed you want... what's wrong with a winged drone that can do tight circles over an area?
Is it the VTOL aspect?
I just want to know what the US mility finds so
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Keep it small in size (Score:2)
I think its potential applications are better suited to where you need a small, remote-controlled flying/hovering device, as compared to some huge personnel-carrying machine.
Let's say that you need to do non-secretive reconnaisance in a confined area, such as urban city streets. Flying something like this that's a couple of feet across, equipped with cameras might be the solution. You could accidentally bump it into things and not have to worry about it crashing (as opposed to a remote-controlled helico
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As cool as that would be, the lighter you get the more easily you can be carried away by a gust of wind. And the lift of a LTA craft varies with the cube of linear dimension. Otherwise, I'd welcome our zeppelin-riding overlords.
Lots of RC people working on the same thing (Score:2)
Tom Swift Jr. (Score:2)
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More of a flying hovercraft, not a helicopter (Score:3)
If you look at the main "lift generating mechanism," it is essentially a fan/turbine, not a wing. As such, it generates its lift by forcing air downwards, developing thrust. A helicopter's main rotors are shaped liked wings (airfoil [wikipedia.org]) on a fixed-wing aircraft. As such, the wing develops lift by forcing the majority of the air over the top of it to create an area of low pressure over the top of it as it rotates.
While its flight my appear to behave like a helicopter, it is not working on the same principles of flight that a helicopter uses.
Re:More of a flying hovercraft, not a helicopter (Score:5, Informative)
The main lift mechanism for this vehicle is the Coanda effect. The acceleration of the fluid as it curves around the body of the "ufo" generates the majority of the lift. The fluid curves because it is a viscous fluid and experiences boundary layer attachment, ie there is friction between the fluid and the surface which keeps it "attached" to the convex shape. I assure you that the thrust generated by his tiny propeller is not nearly enough to lift the vehicle vertically by itself.
"As such, the wing develops lift by forcing the majority of the air over the top of it to create an area of low pressure over the top of it as it rotates."
There is no majority or minority of flow over an airfoil. In fact, boundary conditions for the freestream are generally positive and negative infinity. If lift was only generated by more flow going over the top, airplanes would have a really hard time flying inverted!
Lift is indeed generated by the integration of an asymmetric pressure distribution, but the interesting thing is what causes the asymmetric pressure distribution. Simplified a bit, lift is a reactionary force on the wing, generated by the downward change in momentum imparted to the fluid due to the airfoil's shape.
Or you can explain lift with circulation theory, which is a mathematical model that makes no practical sense to anyone
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Desite your reply as an AC, I have to give you credit for correcting me on this one. You pointed out something that I did miss. I did recognize that the Coanda effect was redirecting the airflow downward around the edges (I have air knives [exair.com] here at work that do this), but missed that the air movement over the surface would also generate a lifting force as well.
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The human issue is interesting... (Score:2)
...I think the more interesting aspect here is that people in the UK have shopped their inventions to the USA, which bought them, and will likely use them ON the UK. In other words, the UK is perhaps selling technology that will be used against them. Of course that's an exaggeration to some degree, as the USA & UK are pretty chummy. But still, isn't it odd that surveillance technology is being giving to other countries? I'm pretty sure we haven't loaned out any of our stealth planes, or even made th
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Tag: eelsonahelicopter (Score:2)
Warp Drive (Score:2)
Which programme is more deluded?
You know you've played too much Half-Life (Score:2)
Small UAV (Score:2)
It could be nice for exploring the inside of buildings, since it can bump into the walls and ceiling without being damaged.
Auto-Rotation (Score:2)
The rotor may be protected, but how will this thing operate in the event of a power failure? Helicopters can auto-rotate, effectively gliding back to the ground. This thing wouldn't be able to do that, so if you're going to use it for manned craft you're going to need to find some way of bringing it down safely in the event of engine failure.
"Wright Brothers" (Score:3, Interesting)
It sounds like it could work underwater maybe.
It looks like it is made for silicon wafer size engineering, microdrones.
I wonder about the linear speed and turning too. Would it be bad to put wings on it? Is that just a propellor and not a turbine like in the Avrocar? Would a turbine be better, and would tilting it naturally turn the machine's direction through gyroscopic precession?
If you put a rocket on one side, would it stay stable?
Could some kind of electrostatics (perhaps wires suspended above the disk parallel to it) help increase air flow by physically drawing it past the surface? Thinking of the "lifter" models.
If it was rising through a charged fluid you might think it could be leveraged. Usable in high atmosphere?
Is its rate of rise limited by the weight of the cowling it needs as a surface?
Does it use rare earth magnets like in engines inside electric car wheels?
Would a spiral ramp-shaped body like Da Vinci's early helicopter design actually work with a fan on top?
Would another fan help in maintaining stability and speed direction changes, like with helicopters tail blades?
I'll believe it when (Score:3, Interesting)
The only thing in the inventor's favour is that the British MOD has a track record of failing to recognise useful inventions (such as RSA encryption, which it had long before R,S and A and ignored) while spending a fortune on torpedoes that don't work, nuclear submarines with no role, tanks with undersized engines, and rifles that don't shoot properly. For long haired left leaning peaceniks like myself half the charm of the MOD is its ability to reduce the risk that we will get involved in a major war by making sure our armed forces are ill equipped to fight one. (that was sarcasm btw). However, my own view is that they regard flying surveillance vehicles as unnecessary. The plan is to cover the entire planet in talking CCTV cameras, which will probably catch speeding motorists as well.
Watch the video on the company's site (Score:2)
They talk about scaling up to fit a pilot near the end.
Did the military forget they tried this already? (Score:3, Insightful)
That's a full scale model of the very same technology! I imagine in this day and age of computer control it will be more successful, especially as a UAV, but how can this guy get a patent on technology from 1958 and claim it as new?
Plans for building your own (Score:3, Interesting)
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Being laughed at is not a guarantee of success (Score:3, Funny)