DaveS,

If by “looping arch” in kite mode you are referring to the Cyclo-Kite, then you are simply repeating errors that I already explained to you and which you never countered. You just ignored them. There is no DS associated with the Cyclo-kite. A wind gradient does not constitute DS. Back looping on a tether does not constitute DS. You seem genuinely incapable of seeing the relevant differences. If you are asserting that any wind turbine subject to a wind gradient is benefiting from DS, that makes no sense. It’s just plain wrong because it’s a meaningless observation. It is based on not making the appropriate distinctions between DS gliders and wind turbines, which I have explained to you, and which you simply ignored, apparently without understanding them.

You seem to be saying that the downwind blade pass of a VAWT on the ground is part of the “kite window”. That makes no sense unless you define anything downwind of an anchor point to be part of a kite window. If so, then the tail vane of a small HAWT is part of the kite window. There is no point in that observation. It has no value whatsoever. So if that is what you are saying, you are mixing technologies for no apparent reason other than obfuscation.

So, so far, everything you have said on your second attempt still makes no sense, and its looking worse for your credibility.

I see that you snuck in “quasi-DS mode” in order to introduce even more ambiguity. Nice back door to slip out of.

PeterS

DaveS,

Only some of his wind turbines are vertically tilted. Others are not vertically tilted at all. How many times do I have to say that before you understand it? You just ignore evidence that contradicts you claims. That is very clear.

PeterS

DaveS,

You’re asking me to agree with your delusion. “ST” does not mean tilted up. You made a mistake because you forgot about the various ST configurations.

I defined “ST” in terms of the way DougS uses it: multiple rotors on the same shaft.

Your error is so obvious but you genuinely can’t see it. That’s a bad sign.

PeterS

DaveS,

When the subject is VAWT, such as the Cyclo-Kite, you are the student. And you are lousy student. As a result, your knowledge of VAWT is close to zero.

PeterS

DaveS,

“A VAWT on the ground is not a kite, so no DS. A static kite that does not sweep across a gradient, no DS.”

Thank you for admitting that you were wrong about the Cyclo-Kite on towers.

PeterS

DaveS,

“Only the tilted airborne STs count here, unless stated otherwise.” And you neglected to state otherwise in your definition, which is why you were wrong.

Thank you for admitting that you were wrong about the definition of Doug’s ST.

PeterS

DaveS,

You are attempting to change your definition of ST rather than to admit that your original definition was wrong. You are dishonest.

PeterS

DaveS,

You are claiming to be right because you are an expert on VAWT. You know diddly squat about VAWT. Your only area of expertise is posing as an expert.

I am still waiting for the record of any research you did on the Bird Windmill. Apparently you have none. If not, then you were lying.

I’m still waiting for you to show me prior art for the Bird Windmill, and I clearly defined the date for prior art. So until I see the evidence, I will assume that you were lying.

PeterS

Hi Pierre,

Yes, your analysis is correct. And by the way, thank you for posting that patent summary for us to see. I wish that the drawing in the patent summary were more clear.

I’ve still been puzzled about what Lecanu and his associates are claiming, and I think that I may understand a little better after re-reading some of their papers. I think that they can actually exceed the “Betz” limit for VAWT. Since that sounds impossible, I’ll explain why I say that:

When a VAWT is stationary and producing power, there is a lot of drag pressure on the rotor, and that rotor drag pressure is resisted by the base of the VAWT sunk into the ground. That pressure does no work because the VAWT can’t move. But if the VAWT were on a floating platform, that rotor drag pressure would move the VAWT downwind as if it were a square sail on a sailboat on a run directly downwind. So work would be done. However, there would be no net gain in power because the VAWT is moving away from the wind. The normal power of the VAWT would be reduced due to the negative translation (reduction) of the true wind speed. So nothing unusual is happening. The rotor pressure can be converted into power (by mounting a water turbine under the VAWT), but there is no net gain in power, so there is no point in doing that.

However, Lecanu and his associates have found a way to achieve a net gain in torque and power by extracting energy from the rotor pressure. That energy is in addition to the energy normally converted by the VAWT, and which is determined by the “Betz” limit for VAWT. They do it by causing the blades to produce extra torque by being forced downwind. The base of the VAWT does not move downwind. But the blades do. Their mechanism is ingenious because it results in a nearly circular orbit for the blades even though they are moving downwind.

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Here is a way to see what they have done: It is as if they designed a VAWT so that the blades would move upwind during both the upwind and downwind blade passes, but then they let the wind pressure force the blades to move downwind to create torque during both the upwind and downwind blade passes. Notice that their central gear is located upwind of the central shaft. So the blades, due to moving downwind, end up following an almost normal circular orbit. In other words, it’s as if his VAWT is designed to have the blades orbit eccentrically shifted to windward, But then the wind blows the blades downwind and they end up in an almost normal circular orbit around the central shaft. It’s a brilliant concept. I’m still amazed. It does not seem to violate the laws of motion.

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The Betz limit is based on how much the air can be slowed by the wind turbine. It does not say anything about the rotor pressure and its potential to do work. It was assumed that the wind turbine had to be stationary, so no extra energy could be obtained from the pressure on the rotor. No movement, no work, nothing to consider.

But Lecanu and his associates are showing that the “Betz” limit, while entirely valid with respect to slowing the wind, does not place a limit on the energy that can be extracted from rotor pressure. The Betz limit completely ignores rotor pressure. Lecanu is claiming, if I understand him correctly, that by using his mechanism, rotor pressure can be converted into a 20% to 30% gain in torque and power above what the VAWT normally produces.

And furthermore, the total amount of power can, at least in theory, substantially exceed the Betz limit (which he calculates as .61 for VAWT, and others have calculated up to .64, depending upon the flow model). In this case, exceeding the Betz limit does not violate the Betz limit. That is because Betz did not consider that rotor pressure could be converted into power.

So if Lecanu is correct, then the “Betz” limit for VAWT is .61 plus roughly 30% of .61, which is .79 or somewhere fairly close to that.

In principle, other WECS, including power kites, could also benefit from Active Lift if inventors can figure out how to do it.

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Normally, allowing the blades to move downwind might cause vibration, which might not be safe. But the Lecanu Version 3 eliminates almost all of that vibration. Their blade orbit on Version 3 is slightly elongated in the plane of the wind. In other words, the upwind blade pass has a slightly larger radius, on average, than the radius to the cross-wind positions. The same for the downwind blade pass.

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The Sharp Cycloturbine -- according to my analysis of diagrams showing how it works, and my observation of especially high torque at a TSR of 2 -- produces extra torque due to Active Lift. As such it is prior art for the Active Lift Turbine, and Lecanu is studying it. But my patent makes no claim about Active Lift because I had no understanding of Active Lift. So the fact that it benefits from Active Lift is purely accidental. It in no way invalidates any aspect of his patents.

The Bird Windmill (including the Cyclo-Kite) has an eccentric orbit shifted downwind which is due to Active Lift, and that is similar to his Version 2, and he is also studying that.

The Active Lift Turbine should produce the most gain in torque when operating at a TSR of 3 and above where fixed-blades are no longer subject to dynamic stall. The Sharp Cycloturbine benefits most from blade pitching and Active Lift when operating below a TSR of 3. The two VAWT could be easily combined by using Sharp blade-units instead of fixed blades. The resulting VAWT should have an extremely high Cp and an extremely wide and high Cp curve. It should achieve a Cp beyond the Betz limit for HAWT.

PeterS

DaveS,

Your lying.

PeterS

Hi Pierre,

I like your point about how kites make use of Active Lift to fly (sustain altitude by converting energy). That’s a very important point, even though it’s obvious. While their flying may not produce power directly, it places them at a higher altitude where more power is available. So it is possible that kites were the first devices to make use of Active Lift.

However, historically in times long ago, conventional kites flew stalled most of the time. They relied on drag rather than lift. So it might be more accurate to say that they made use of “Active Drag”. Then, as kites began to fly across the wind at considerable speed in relatively modern times, they began to create high lift like modern airfoils, so those kites may be said to be using Active Lift.

PeterS

DaveS,

The term “reversible helical pitch” has no generally understood meaning for VAWT. Please explain what you are talking about.

PeterS

DaveS,

You are claiming that I have no advanced knowledge of VAWT because I have not produced power kites. That’s nonsense, as usual.

You are not equipped to get into a pissing contest with anyone because you inevitably piss all over yourself. Go fly a kite.

PeterS