True, but some AWES (crosswind, Daisy) use mainly lift, while some other AWES (Guangdong parachute, Magenn) use mainly drag . Lift devices are more efficient but some advantages (simplicity, higher elevation angle) could perhaps come from drag devices.
This important distinction is found in established wind energy with lift devices (3-bladed HAWT, VAWT in Darrieus-type), and drag devices (Savonius-type). Lift devices are far more efficient.
It’s no surprise AWES has lift and drag all mixed up.
They’re at an elevation angle.
Wing lift has a drag downwind component.
Do you get lift and drag type helicopters? Hope not.
A rotor at any angle to the local wind has an upwind an downwind side
Hi Pierre: The term “downwind” (and upwind) are also already taken in wind energy.
It refers to the placement of the working surfaces, upwind of the base station or downwind of the base station.
Regular horizontal-axis propeller-style wind turbines with the rotor located downwind of the tower are referred to as “Downwind” designs. The stated advantage is usually passive automatic aim, whereas the disadvantage is often the “whack” that afflicts the blades as they transit the “wind shadow” of the tower.
So by established nomenclature, most AWE concepts, including SuperTurbine™, would be called “downwind”.
The advantage of “upwind” designs, which encompasses most utility-scale devices, is smoother airflow through the rotor, due to being placed in fresh wind, upwind of the tower.
“Upwind” and “Downwind” are two major existing categories of wind turbine nomenclature, after
“Lift-based” and “Drag-based”.
Next you have the method of overspeed protection:
“Pitch controlled”, “Stall-controlled” or “furling”
There is ALWAYS some company promoting some “new” downwind, 2-bladed wind turbine. Usually it is just renderings, though sometimes they actually get one built.That never changes.
The latest one I saw featured active yaw control.
That lets it turn sideways, and park the blades horizontally, to survive storms.
But usually they rely on passive downwind rotor orientation.
They never catch on, usually never get built, and if built, they usually explode or have a tower-strike at some point.
They often cite offshore applications, and the ability to have a larger rotor than whatever is common at the time of promotion.
Stated advantages are faster rotation, less material used, longer blades, and avoidance of tower-strikes. hmmm…
For now I’d be happy with getting long-established terminology to match what is long-established:
“lift machine” vs “drag machine”
“upwind” vs “downwind”
I also think “yo-yo” is “cute” but not accurate.
More like a fishing pole reel than a yo-yo.
None of the AWE reeling devices I’ve seen really acts like a yo-yo.
As I’ve joked in the past, it might refer to the promoters more than the device.
The thinking is to split into the four variants of «bounding»/«hovering» and «lift»/«drag». Then split further into the most common archetypes, if further classification makes sense.
Bounding: changing between production (downwind motion) and return phase (upwind motion)
Hovering: Plant is more or less stationary, any movement back an forth relative to wind is not related to power harvesting directly
Lift: Blades are producing more lift than drag
Drag: Blades are producing less lift than drag
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I know bounding/hovering seems odd and new to everyone, but if you look at their meaning in bird flight it immediately makes sense, and the terms are not currently loaded with meaning.
How about “wasting”? As in the machine wastes half of the energy on the generation phase, then not only wastes ALL of the energy on the return phase, but actually wastes even more of the energy previously generated! A wind energy device that uses energy - wow. You can tell there are no real wind people in AWE.
Those look like SD turbines. A resurrection of a failed design from a bankrupt company - trying to remember their name… Wait, just remembered the name: “Proven”. I guess at first it was proven to work, but then later, proven to fail… The original company Proven was from Scotland if memory serves. I know a lady around here who had one. I think it broke down. I was originally very impressed with the design. They had an interesting method of overspeed protection, but I think that turned out to be the Achilles heel. From what I remember, I think they all break down eventually. I think that was why the company went bankrupt. I used to think that was a compelling design, until they started failing on everyone. People from outside wind energy will just fall for anything. Just because a website that says their stuff is great doesn’t mean it is true. Then again my SuperTwins and my Firefly are either upwind/downwind or dual-rotor downwind, and they stay running for years. I did, however, have to deal with tower wake effects that can be real dealbreakers. I found ways to address the issue but I found out the hard way, the tower wake is for real. That’s why Skystream has curved (scimitar) blades - so they don;t all hit the wake at once. But the Skystream had balance issues as well, and many other issues, and the company, Southwest Windpower, went bankrupt. I know one of the founders. Still, in general, downwind machines tend to not last. Too many problems to go into right now, but you don’t see very many operating, and if you do, stay tuned cuz it will probably be not running before long.