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This thread is privately moderated by maguro, who may elect to delete unwanted replies.
Jul 09, 2018, 03:48 PM
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The tuft test I did a few years ago shows that the vortex sheds and reforms a lot when maneuvering the plane. I don’t believe the concave step would do much to change this, but as Jack said, we don’t have any testing to document what it might do.
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Jul 09, 2018, 04:34 PM
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Hereís a paper on a KFm1, which is referred to in this paper as a cusp airfoil vs. NACA 0015.
Jul 10, 2018, 03:13 PM
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The KF Trapped Vortex applied to a YAWT.

VAWT LENZ2 (0 min 58 sec)
Jul 10, 2018, 03:25 PM
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Here is an interesting comparison between a propeller and trapped vortex.

Der Vergleich: ElvWiS vs HAWT (5 min 31 sec)
Jul 10, 2018, 04:32 PM
Build straight - Fly twisty
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That is an array of S type turbines. I can't see how that relates to anything KF.
Jul 10, 2018, 07:10 PM
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Quote:
Originally Posted by Whiskers
That is an array of S type turbines. I can't see how that relates to anything KF.
Whiskers.... everyone sees the world through their own eyes differently. When we filed for a patent back in 1971, we claimed that our airfoil with a step produced a vortex attachment. I also stated this in my Ultimate Paper Airplane book in 1985. My view is that when an airfoil creates a vortex, it produces slight forward pressure as well as stall resistance. This wind turbine uses a similar principle. As far as I know, Floyd and I were the first ones to introduce a vortex capture in aerodynamics.

However, you are entitled to your perception. And, I am entitled to mine. It is whatever it is.
Jul 10, 2018, 07:51 PM
Build straight - Fly twisty
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No, The S type turbine works on the simple principal that the concave side has greater drag than the convex side and so in an airflow the thing rotates.
Just a simple result of differential drag.
In the array depicted the S elements are rotated relative to each other to produce smoother torque.
Jul 10, 2018, 08:15 PM
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Dickeroo's Avatar
Quote:
Originally Posted by Whiskers
No, The S type turbine works on the simple principal that the concave side has greater drag than the convex side and so in an airflow the thing rotates.
Just a simple result of differential drag.
In the array depicted the S elements are rotated relative to each other to produce smoother torque.
Okay.
Jul 10, 2018, 10:18 PM
Build straight - Fly twisty
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The other examples you have posted were of the KF variety.
This particular one, which is not, managed to sneak through under false colours
Jul 15, 2018, 11:34 AM
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Dickeroo's Avatar
Here is an interesting comparison between a Kelso wind turbine, which appears to have a step and a conventional propeller.

The Kelso (0 min 16 sec)
Jul 16, 2018, 09:13 AM
Jack
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Is the motion on that 5 bladed fan in the background arrested by the camer's frame rate? Or is it turning that slow?

Jack
Jul 16, 2018, 01:15 PM
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Quote:
Originally Posted by jackerbes
Is the motion on that 5 bladed fan in the background arrested by the camer's frame rate? Or is it turning that slow?

Jack
Jack....
Donít know the answer to that one. I think that this video was posted in 2010, so it has been around a while.

Here is a KFm4 and a KFm2, but I donít have any info on them. Also, a close-up viewing from the trailing edge of the KFm4.

Eolienne axe vertical Vawt C-rotor canstein type (1 min 42 sec)

Lenz2 Turbine from recycled materials. (1 min 0 sec)
Jul 16, 2018, 01:54 PM
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For anyone who wants to build a backyard KF wind turbine... here it is.

Open Source Wind Turbine v1.0 - Construction Tutorial Animation (6 min 25 sec)
Jul 18, 2018, 05:11 PM
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Dickeroo's Avatar
This is a Vimeo video of a ParaGlider using a KFm1 type of airfoil.

https://vimeo.com/ozone/xxlite


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