Touche. Well debunking Brainwhere is pretty easy though. Only the brainless wold invest in Brainwhere. Wait thats recursively untrue…
I don’t think so, it is rather a vertical-axis wind turbine (VAWT) put into the horizontal.
I agree it is not promising, not to say worse.
Of course Shepard’s design is 1000 times far better, the problem being a very long tether in regard to the rotor diameter.
"[quote=“PierreB, post:22, topic:264”]
added a disproven Honeywell-style rim generator
I don’t think so, it is rather a vertical-axis wind turbine (VAWT) put into the horizontal."
Pierre: Thanks, I see what you mean, now that I watched the video, which says the generator is in the blue enclosure hanging below. I had assumed the rim had magnets. Does it? They don’t say. It is indeed a cross-axis turbine (sideways VAWT) but maybe not with a discredited Honeywell-style rim generator. They added a rim. Cross-axis turbines are pretty-much debunked by this point in time. Rim generators: Also pretty-much debunked or shown inadvisable, so how does this generator work? I don’t see that explained. Gears? Friction? Magnets in the rim? They probably don’t know either. But also, watching the video explaining how this “will work” in the jetstream, I’m thinking, OK so you have a 120 mph wind. Your blades operate at a 4:1 TSR, so the blade speed is 480 MPH. The blades would just break and fly off the machine, even in a 30 MPH wind. I think he said he thought it up while drunk? Well, there you go.
I correct a bit: it is an Honeywell-style as the generator works the rim, that is not usual for a vertical-axis wind turbine (VAWT), the Honeywell turbine being an horizontal axis wind turbine (HAWT).
So this design seems to cumulate all possible problems.
Ha ha that is funny - a design that finds a way to combine all possible problems. Wow. That is a good summary of where the Professor Crackpot Syndrome often leads to.
Speaking of Shepard, what about a stack of SkyWindPower machines that had already moved beyond the cross-axis design? What ever happened to SkyWIndPower? Seemed like a promising idea - has SkyWindPower “quietly gone away” like the rest… PJ?
I don’t see that, just like I don’t see the blades slicing through the blue thing.
These are the only criticisms from first principles I see:
How much friction? I see a smooth ring rotating.
Putting it on a tower is a good way to test that, after simulations. Or before simulations, make a rotating disk and attach your blades to it.
Look at the rendering of the stack of modules above the truck. How can these blades rotate without slicing through the tether? I don’t know how much friction, but normally we arrange things so the high-speed parts of blades travel through air only. You “see” a smooth ring rotating or you imagine it? Looks to me like the ring has to rotate as fast as the blades - or does the ring not even rotate at all? Who knows!?!?!
And regarding centrifugal force, there is a lot of previous vertical-axis experience to draw on. The normal solution to centrifugal force is to give the blades a troposkein (banana) curve, or support ech blade with multiple arms (weight, drag). Of course the real solution is to align the blades with centrifugal force, hence, the good ole’ “propeller” configuration. But hey - you can change it! Who cares about “what is known to work best”? Not “the good professor”, that’s for sure.
Imagine they’ve solved the problem of breaking blades and (the software problem of) getting the thing to fly. What are now still first principles problems with the system (flying at a lower altitude). What are first principles reasons why it could work?
This is just another idea for an awes, like I see posted here often. It is more achievable than some, like the Beaujean thing. So I don’t see why the discussion has to be more negative than in all those other threads. Increase the number of angles from which you look at a problem, and the deeper your understanding will be.
I might have looked closer at this, but just now it doesnt seem worthwhile to me. Perhaps if they release something more than a 3D rendering…
Let me just say this: Like the Laddermill (Laddermill, third post), the wings are generating crosswind energy, but at the same time moving the wings for power generation perpendicular to the wind direction (wing moving upwards and wind horizontal). This does not scale well I think with higher rotational speeds. You get a lot of force at low speeds, but little power when combined with fast rotation.
The reason that generating energy with motion perpendicular to the wind direction is a consecuence of apparent wind. With such a movement, apparent wind will work very hard against the wing motion. It would be very similar to a Kitemill/Makani Yoyo rig producing directly upwards. Anyone familiar with kites will know that once the tether is released somewhat (and kite moves upwards), the tether force will immediately be almost slack. It’s a matter of geometry, a bit hard to explain.
Another way to approach this is to understand that when harvesting wind energy, you are harvesting the difference in speed wind relative to ground. The tether force acting in the direction component directly against the wind is the basis for your power generation. If the tether is pointing mostly upwards (to reach high altitudes), you are probably not going to harvest much energy because the tether needs to be very strong for a small horizontal component.
Add to this that if you divide the circular motion into four quadrants, forward, aft, up down, only the forward quadrant (a bit simplified) is generating energy, up and down are pure transport while down is a pure loss (but necessary for the function of the device). So only 1/4 of the time, the wing is active.
It might be better if the device was headed mostly downwind instead of upwards into jetstreams.
The reason, why we’re more negative about Brainwhere and Michael Perlberger is, that he’s cocky. Presenting himself like a savior. No humility. He’s actually trying to trick investors into giving him money and get public attention. When he will inevitably fail, people will be disheartened with the whole of awes. He has a lot of credibility, having been in business for a while and having a related MA from Delft. So he should know better. “It is science fiction, but it works.” He states that with the utmost confidence without having tested enough. “Humankind will benefit from it” That’s also why I got into awes, but he says it like he is Prometheus himself.
In contrast to that, the Beaujean thing is a concept by a dead person brought up by a fellow forum member in the category “lounge” with the preface that it’s crazy, but we should discuss it for fun.
Now how can I, with much less credibility, make such a harsh judgement? (Thx, @Windy_Skies, but I’m not an expert either) Because there are simple, understandable reasons, why this will not work. I will not do a detailled analysis since noone’s paying me to do one but this concept can be dismissed without one.
First things first: Can this thing fly as a kite? Yes. Standing still it’s just a mupltiplane. It has pitch control on every surface, so it should be steerable as well.
Can this fly on itself? Probably. Control is very difficult, but it theoretically it should be possible. Even without airfoils or even blades, one can make a magnus effect plane. Is it steerable? Probably. If not one can always add an empennage to the non-rotating part.
Can power be extracted? When he shows the test article in the video, he says how he can get the system to roatate when it stands still or turns very slowly. Then all is good. Positive aoa in front, negative in back and all of them get some wind. Then it is easy to have a bit more lift up than down to keep the system in the air.
But as soon as one starts cranking up the angular velocity, the relative wind on an airfoil changes drastically, other effects set in, the fast moving blades in the back are in the wake of the fast moving blades in front. When the front blade uses its potential as a perfectly aligned crosswind kite, it can faster than the airspeed. But then everything needs to move faster than the airspeed. the top blade when moving backwards would go against the relative wind with the airflow from back to front. I don’t really know what the back blade will do but it certainly won’t be in the position as shown due to relative wind. If the radius is gigantic, so that the front blade does have no effect, then the back blade could have a second optimal point of crosswind flight. At the bottom the blade can provide lift for the system. It has very high relative wind. Namely the wind speed outside plus the speed of the roation which can be higher than the wind speed. Very high drag, extracting energy from the system.
Mechanically this thing is challenging. Pitch control on every whole wing, not just airfoils, rotating very fast. That’s extreme mechanical loads and the whole thing is supposed to be net energy positive.
A generator in the rim. Possible, but unneccessarily complicated. So much friction. There’s a reason why hubless wheels haven’t taken off. Usually in a generator all parts are at work. But not in this one. A large part of the rotor is not in the stator at any time. This means a lot of dead rotor weight.
The concept can be dismissed much more easily when looking at alternatives instead of stating why brainwhere is stupid. Just imagine a not moving makani plite optimised not for crosswind flight, but standing in the air. The system is soooo much less complicated. It’s just a kite with rotors. Very stable and reliable. The rotors move optimally crosswind all the time. A simple well tested hub generator. Much larger swept area per mass, even when not going crosswind! Now imagine it going crosswind. The system which is already much better than brainwhere suddenly becomes a multitude more efficient.
So much business bullshit.
Now he’s looking for a partner in crime. Someone with “Existing network of C-Level contacts in relevant governmental institutions, utilities and the investment community”
Dr. Beaujean raises the good questions, in first the proportions of the tethers and the flying rotor as the device scales, in second the multiple wings in order to avoid cubed mass penalty.
The present design is a variation of a VAWT put in the horizontal.
Two sideways airborne versions of the vertical-axis icebreaker propeller:
My prediction: “Vaporwhere” - you’ll never see one fly. Too complicated.
And cross-axis turbines are a known bad design direction in wind energy. Twice the weight per unit power, high nonsteady unnecessary bending forces on the blades, too many unworkable aspects, temporarily glossed over by the irresistible lure of sexy renderings…
Really good find!
The ship propeller addresses some issue that are not present in airborne wind turbines.
Here’s a wiki article ( should have looked for that sooner):
All cyclogyros have a system to counteract torque. The brainwhere system will probably need one, too. The weight of the stator can’t suffice. But I guess engineering comes after selling for our glorious savior.
By the way- he has claimed to have filed a patent. I can’t find it. If it is granted, we should invoke the powers of the old forum to find some prior art.
Looks like they’re headed toward the well-worn path of “mission creep”, where they decide their device will never compete in providing electricity at a competitive cost, anywhere in the world, so they will use an airborne platform to provide a wifi connection.
Some things never change…
This is a much more plausible telco relay concept:
(actually used http://awesystems.info/orgs to find this.)