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May 26, 2018, 04:55 PM
Build straight - Fly twisty
Quote:
 Originally Posted by RexGalore I'd have accepted 90mph. What's 0.098822874413 mph between friends?
8.696412948344 feet per minute, now that you ask

Dick's headline sure grabbed my attention
May 26, 2018, 05:17 PM
Out Standing In The Field
Quote:
 Originally Posted by Whiskers 8.696412948344 feet per minute, now that you ask Dick's headline sure grabbed my attention
That sounds slooooooooooooooooooooooow, to me anyway.
But we're still friends, anyway!
Latest blog entry: Rare Bear
May 26, 2018, 06:23 PM
"long stretch of water..."
Quote:
 Originally Posted by Whiskers 8.696412948344 feet per minute, now that you ask Dick's headline sure grabbed my attention
Hah. I could probably fly my Nutball that slow. 😀✈

Pat
May 26, 2018, 09:02 PM
looking up, down under
Quote:
 Originally Posted by Whiskers 8.696412948344 feet per minute, now that you ask Dick's headline sure grabbed my attention

i hope you don't do your own accounting
May 26, 2018, 10:22 PM
Build straight - Fly twisty
Quote:
 Originally Posted by scruffy1 i hope you don't do your own accounting
No I don't. I cohabit with The World's Greatest Book-keeper.

Are you saying that 0.098822874413 mph is not 8.696412948344 feet per minute? I am notoriously bad at math.
 May 26, 2018, 10:58 PM looking up, down under i just re-read the post - your maths is probably correct (didn't obsessively check), but my interpretation of the speed you were referencing i thought was the actual speed of the plane, not the difference in the calculation of the speed seemed ~8.7 feet per minute was less than stall speed carry on !
 May 26, 2018, 11:10 PM Build straight - Fly twisty Ah yes, one hundredth of a mile per hour would indeed be slow. The guys who are obsessed with hovering do ground-speeds like that. (yawn)
Jun 12, 2018, 02:55 PM
scratchbuilder

# KFm 2 in ground effect

I managed to get the Ekranoplan to fly in ground effect. On the passes at the beginning of the vid, there was no need to touch the elevator. When it descended towards the water, the compressed air lifted it automatically- enjoyable and relaxing super low flying!

 Modell-Aviator Ekranoplan am Edersee (1 min 47 sec)
Jun 12, 2018, 03:22 PM
Registered User
 fpv cuda launched off school buss (9 min 24 sec)

my bus doing work. Got to love that kfm3!

one day I need to actually see how much she will lift.
Jun 12, 2018, 05:26 PM
Registered User
Quote:
 Originally Posted by Sr71freak https://www.youtube.com/watch?v=GEqeJ0IAkNQ my bus doing work. Got to love that kfm3! one day I need to actually see how much she will lift.
Some years ago, the Bloody Micks did some testing between a conventional airfoil and a KFm3. One of the tests was weight lifting. The sound cuts out at one point, but then returns. The KFm3 was able to lift 79oz. compared to 71oz. for the conventional airfoil. They conducted other tests for stall and stability as well.

 weight lifting part 3 (6 min 10 sec)
Jun 12, 2018, 05:47 PM
Registered User
Quote:
 Originally Posted by Dickeroo Some years ago, the Bloody Micks did some testing between a conventional airfoil and a KFm3. One of the tests was weight lifting. The sound cuts out at one point, but then returns. The KFm3 was able to lift 79oz. compared to 71oz. for the conventional airfoil. They conducted other tests for stall and stability as well. https://youtu.be/rspdbPaMY9c
Thanks, I'll check that out after work.
 Jun 27, 2018, 11:09 AM Planes are for trix You guys have been busy in here So many great builds. Love this thread! Flew some Powered Flytraps this weekend with the KFH foil. Fun slow flying power setups. 1 hour builds from razor knife, to sky (we need to cut that down)
Jun 27, 2018, 07:55 PM
Registered User
Here is an interesting paper I just stumbled upon.....

Darrieus, Vertial Axis, Wind Turbine, Kline-Fogleman, Step, CFD

Abstract: Airfoils which have backward facing steps are called Kline-Fogleman airfoils and those have previously shown to have lift/drag enhancement potentials over conventional airfoils. Darrieus vertical-axis wind turbines rotate by the lift generated on its airfoils. The exploration of power enhancement potentials of such turbines is a current scientific topic in the literature.
In this study, the effects of stepped airfoils in a Darrieus turbine is studied by validated computational fluid dynamics (CFD) simulations, to the author’s best knowledge, for the first time in the open literature. The comparisons revealed that this has both positive and negative effects. Optimized step geometries with active flow control may eliminate negative aspects and improve overall performance. This study is expected to be a reference study on this area.

http://web.deu.edu.tr/fmd/s56/S56-m8.pdf

### Images

Last edited by Dickeroo; Jun 30, 2018 at 04:13 PM.
Jun 27, 2018, 08:11 PM
Build straight - Fly twisty
Quote:
 Originally Posted by Dickeroo Here is an interesting paper I just stumbled upon....
The NACA 0021 is a funny old fat section to use for a wind turbine.
I can't think of a valid use for a symmetrical section for a one-sided application such as a wind turbine.

### Images

Jun 27, 2018, 08:30 PM
Build straight - Fly twisty

# Ah! Now I see...

I have just slightly diluted my ignorance of wind turbines.
You can see that a step on the inner surface of the down-wind foil would indeed help with self starting.