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back to article 'First-ever' flight of robotic ornithopter announced

Famous crazycraft company Aerovironment has won a $2.1m contract to further develop its robotic "Nano Air Vehicle" (NAV), which flies and hovers using flapping wings like a hummingbird. The company has also released a video of the innovative craft in test flights. According to Aerovironment, the fluttering NAV achievement is …

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Anonymous Coward

Efficiency and endurance? Not really

“The NAV program will push the limits of aerodynamic and power conversion efficiency, endurance, and maneuverability for very small, flapping wing air vehicle systems”

Not if they count birds and insects it isn't. Not by a factor of a million or so!

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Grenade

Deception Point

I'm guessing it'll be able to recharge by inducting the EMF from mains cables and transformers as well...

Next there'll be a Dune style version with a poisoned dart on the front.

Are there any military devices/weapons that weren't invented by fiction authors ?!

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Paris Hilton

Expensive Toy

I've got something like that at home, cost me £14.99. It's a miniature R/C helicopter. I'm not sure the development of flapping-wings robots is all that useful when rotors work very nicely.

Isn't this the equivalent of somebody coming out with a car with legs than runs down the road? Here's a thought: you don't see many wheels in nature, but I don't know of any creatures that can outrun even the cheapest of nasty car tat clogging up our roads.

Paris becase even she would know better.

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Bronze badge
WTF?

Ahem

What does the 'thopter design offer over a rotary wing alternative?

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Boffin

Reynolds number

Efficiency

When the Reynolds number his high, the fluid flow becomes turbulent, wasting energy

When the Reynolds number is small enough, you have laminar flow, in which all the energy is used towards your goal.

That's why a big, low rpm fan is much more effective and quiet than a small, high rpm one.

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Wing advantage: my guess

Is they're better able to survive collisions? I saw wildlife on one or something about butterflies, and how they can still fly when their wings are torn to shreds, perhaps there is an advantage there.

Also, if they can make one this size that works, they could potentially make it smaller still. I'd guess that mini helicopters couldn't be shrunk to the size of a blue bottle and still work? Although blue bottle sized helicopters would be very cool toys.

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Thumb Up

@Frank Bough

"What does the 'thopter design offer over a rotary wing alternative?"

Bags of win.

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Boffin

Not the first

As far as I know, the DelFly of the Delft University of Technology (and another project by David Lentink of the Delft University and Wageningen University) was earlier (maybe even the first): http://www.tudelft.nl/live/pagina.jsp?id=861eb007-c9e5-4f7e-a9b3-a81d36b3a32f

See also http://www.youtube.com/watch?gl=NL&hl=nl&v=rmf3qWqox7k at around 5:50

But probably since it didn't happen in the States, it did not exist.

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Boffin

Reynolds Number

Reynolds Number 1 isn't that the speed at which ripples travel?

traveling slower than a ripple means the air is clean each sweep, travelling faster means cutting the wake each stroke more noise less efficient.

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Pirate

HE IS THE KWIZATZ HADERACH!

Is it any good for flying around deserts and checking out spice harvesters?

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Happy

Very interesting exercise

but I'd have to agree that aside from the academic point of view, the benefits are dubious.

The only reason nature uses flapping based propulsion systems is that nature cannot produce an infinately rotational ball joint.

Even the helicopter, which beats the laws of physics into submission, rather than working with them like the plane wing is vastly more efficient than birds at powered flight.

This is down to the fact that rotors, propellers and jet turbines can continuosly rotate in one direction. Birds and insects lose a tremendous amount of energy each time their wing reaches the end of its travel, as they have to then put twice that energy back in to change its direction.

I'm also struggling with the concept of noise reduction. Surely anything that flaps its wings at such a high bmp is going to generate an enormous amount of noise? If you think about it, the wing is a relatively flat surface moving back and forth at a high frequency - just as the surface of a speaker cone does.

We've all heard the disproportionate amount of noise something as tiny as a blue bottle generates? And the blue bottle has no engine noise.

As with most DARPA projects I read about though, I love it! Practical? Nah! Fascinating? hell yeah!

I would certainly be interested to hear more about wing resiliancy in comparison to rotors though. I suppose it depends on the makeup of the wing itself, more than anything else.

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@Richard Stokoe

Yes, but now take your average car off-road and compare its performance up hill and down dale compared to a horse. There's a reason cars do well in that contest: it's 'cos the level playing field we call a road is designed for them to work on.

Nice thing about leggy devices/creatures is that they DON'T need a smooth, flat surface to operate on.

As for the ornithopter/helicopter question, I imagine it has to do with the viscosity of air at smaller scales. Same reason it's easier to fly at the scale of a fly (indeed for really tiny creatures the challenge would be staying on the ground) than it is at the scale of a jumbo (pachederm or jet)

I'm no aeronautical engineer, though, so I couldn't say for sure.

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Black Helicopters

As the controllers laugh histerically

"Future versions of the bugthopter are expected to be able to "perch" in suitable locations, relaying sound and video back to their controllers up to a kilometre away, AS they also drop off very small payloads such as tiny clouds of anthrax..."

There, fixed that for ya....

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Breaking news:

North Korea is said to be stepping up it Taepodong XII Rolled-Up Newspaper Program...

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Anonymous Coward

@Avalanche

Close, but no cigar. DelFly2 clearly has a tail for control, so doesn't fit in the tailless category AV are claiming a first for.

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Coffee/keyboard

@Dr Harkin

Thanks Doc, coffee on keyboard and screen moment there.

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Silver badge

@ Frank Bough

'What does the 'thopter design offer over a rotary wing alternative?'

The opportunity to acquire bags of DARPA funding.

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Boffin

@Psymon

Actually, bacteria do a very nice rotary joint (actually an electric motor) - check their flagella, but it doesn't scale well.

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