Dr. Beaujean's airborne wind turbine

Because I don’t know the actual design in detail it’s difficult to know, but; Say the magnet size is 10 cm each, and the coil is equal to the chord of the wing, say 3 m each. The distance between the wings might be, say 50 m. In this case, the coils and magnets are only overlapping area 6% of the time. Its going to be difficult to extract all the energy in this short timespan. I would expect the distance between the coil and magnet would have to be less than 10 cm? For normal electric motors the distance between the magnets and coils id extremely short, and also the coils will have heavy ferrite (?) cores. I can’t see any way you could design a lightweight motor like this idea describes.

Why isn’t a gearbox a better solution for such designs? (referring to @PierreB 's picture of a two propeller windmill). Dual “propellers” would surely escalate costs and cause additional trouble with turbulence?

A gearbox can be heavy. Beaujean’s design has also a possible advantage as the blades are held with the rings by their respective tips, avoiding some lever effect, but with also some possible counter-effects like the weight and the complexity of the rings and the machinery.
I showed Dual “propellers” to compare with Beaujean’s design.

Is not possible using the rings? Only the tips of the blades have to be very close to the ring.

One of the biggest issues are the ‘air bearings’. Those would need to have extremely low friction and still take significant load in direction of the rotational axis. 60 m/s (210km/h) is much faster than bearings usually handle. Even if it were the tree rigid rings, keeping the pressure differential in the bearings would result in significant losses. (As far as I understand it, air constantly needs to escape)

Ooops forgot the stacked arrangement

Thanks @Tom I’ve probably got a drawing of one somewhere :grin:

Anchors on the seabed already in this Beaujean case

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Maybe. I don’t think its clear. The lines do converge to a single point which suggests that they connect to a single tether or anchor.


Quick sketch of another counterrotating turbine concept.

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It is true. If the ring is solid, the issue of proximity may be solved to some degree. An improvement on the design could be to place the coils on the ring such that the could could be places continuously along the ring. This will also place additional constraints on the wing tip thickness of the wings.

Maybe my problems accepting the design is due top not understanding the construction in detail.

To hilight my doubts about keeping the wings (single skin?) at this aspect ratio flying without colliding, look at eg. the Pter Lyn Phantom kite. With gusts/changes in tension, there will be “jellyfishing”. My guess is that this would happen quite severely for this rig even without gusts. This is because the kites will be passing in close proximity, and the jellyfishing will not be gone when the next wing passes.

Looking eg. at 3:47

Here’s one more

The determining factor of a wing performance is not only aspect-ratio, but also the initial L/D of the wing profile. It seems to me a very unusual choice to design the wings with such an high AR. If they are replaced by some other wings with AR around 10-15, the power plant might be easier to construct.

For instance: How will we stiffen the profile angle-of-attack to keep it in optimum setting while flying? I believe you would need an infinite stiffness rear edge tether for this, along with constant wind conditions. Also, with the radius very different at the outer and inner side, the profile would need (perhaps) to be different to account for this. After doing that job for a design wind speed, will the design scale for different wind speeds and for different power extraction in the magnet/coil devices. Not a showstopper perhaps, but definitely a need for some bleeding edge technology in kite design.

Wow - when I see these videos I start thinking building a rig with 2x6 of these kites flying counter rotating would be so much fun!

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Quick sketch of another counterrotating turbine concept.

You can drop the vane if you can control the speed of either ring, and you probably need such control for depower anyways

Bet it would still need a vane as the friction won’t be exactly the same even if speed is matched. Probably needs a vane above the generator as well and some swivels…

If you can control the speed of the rings ant the power takeout, you should be able to drop the vane. But you dont necessarily need to, perhaps the vane is a good idea.

http://www.energykitesystems.net/Beaujean/index.html
@JoeFaust has collected some info on the Dr. Beaujean (†2014).

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You guys are mostly rehashing probable-, typical- Professor-Crackpot type stuff.
Two giant rotating discredited Honeywell bicycle-spoke-turbines, with-peripheral PMA generators. Add air-hockey “frictionless” travel. All in salt-water. Of course, why not make it for 500 MW? Anything else? As usual, the company probably wanted millions but couldn’t show you even a science-fair-scale demo. Come on Professor, just use an old air-hockey pump! I’ll let you use my garage to build it!
Counter-rotating: a common feature that newbies typically think they are the first to suggest. Even when an actual professor got a grant to try it, he STILL used two regular generators instead. He was one of my precursors with the California Energy Commission. I was surprised how interested they were in my results - turns out most projects never amount to anything and are never even completed - who knew!?!?! Starting to see a pattern? All those ropes - no drag? Renderings - they make you think crazy stuff is real.
Other than that, I like the idea. One more proposal that wants to be a SuperTurbine when it grows up.

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Perhaps repellant forces could be used to fix the blades. Some quick sketch here:

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Yes, its true… putting the problem to good use. Though the force is not strong enough to do this alone. I think you still need a “railroad” like system with ball bearings. But this design would likely add less vibrations to the system.

The repellant force argument was mostly important before I realized there would be a rigid ring leading the wingtips

I think the high aspect ratio of the wings may be due to the requirement of the shape stability of the rings, as numerous wings are implemented.
The rings can be a weak point as their stability of shape depends on flexible wings.