From IEEE Spectrum,a "cyclogyro", or "cyclocopter":

 

Fundamentally, a cyclocopter is similar to a helicopter in that it creates lift through rapidly moving airfoils. Unlike a helicopter, a cyclocopter's airfoils rotate around ahorizontal axis, continually changing their pitch in order to generate thrust in one single direction:

It's certainly not a simple system, which is why this idea (which has been around in the form of various prototypes for nearly a century) only got off the ground to make a first untethered flight just recently, thanks to a lot of hard work from Moble Benedict and his team at the University of Maryland. They've been developing a cycloidal rotor system made of carbon fiber and titanium that's so far been applied to both a quad cyclocopter and a twin cyclocopter, and they've successfully gotten the two rotor version (with a supplemental tail rotor) into an untethered and more or less stable hover.

You're probably wondering what the advantages of such a complex system are, and luckily, there are a few. Primarily, it's suggested that a cyclocopter would be more efficient than a helicopter, able to generate more thrust for a given amount of power. It's also thought that cyclocopters will prove to be more maneuverable, since the thrust can be vectored very rapidly. On the downside, you've got the overall complexity of the system to deal with, and the weight of the rotors might cancel out any efficiency gains.

 

Paper (pdf) here. Video of earlier demo:

 

Views: 5392


Developer
Comment by Randy on July 25, 2011 at 5:37pm

Awesome.  I've never seen anything like it.

 

One advantage over a quad is that it can likely fly upside down.  Of course a regular heli can do that too but this thing is also more compact and slightly less scarry to be around.

Comment by Yuan Gao on July 25, 2011 at 7:07pm

Holy sh...that's awesome and scary.

 

This is interesting to me because of my background working on wind turbines - the advantages they mention are the same advantages that vertical axis wind turbines have over horizontal axis wind turbines.  But if they're that similar, then this means they might have the same kind of problems with cyclic loading on the blades (and therefore faster fatigue).  But probably those issues would only affect large scale machines.

Comment by Cliff-E on July 25, 2011 at 9:08pm

Cool yes, efficient, likely, practical... not really. (not the time difference in the video, 3+yrs in the making).

 

If they can get the blades smaller than a EDF in diameter, then I can see some applications.


Developer
Comment by Jason Short on July 25, 2011 at 9:33pm

I've seen these in Tug boats and their called Voith Schneider propellers. I played with a prototype one in Munich's amazing industrial museum. The cool part about the props is that you can direct the propulsion in any direction in an instant. So a tug boat would point the blades vertically allowing it to travel sideways or backwards. 

Comment by MarcS on July 26, 2011 at 1:25am

Hi Jason,

the Voith Schneider propellers was the first that came into my mind, too :-)

If you see the complexety of the system, you begin to like the simple construction of a helicopter... Very nice engineering, anyway!!

Comment by Peter Seddon on July 26, 2011 at 3:47am
Can it cut the grass at the same time? - now that would be an advantage.

Peter
Comment by ionut on July 26, 2011 at 1:51pm
They should try it on water:)
Comment by Greg Fletcher on July 26, 2011 at 9:23pm

Rattletrap prone to failure. I would wonder about its' efficiency. Lots of moving parts.

Comment by Greg Fletcher on July 26, 2011 at 9:26pm

For a aero/mech engineering project, it's excellent.

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