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Jun 09, 2010, 10:04 PM
agony sweetns the victory
atjurhs's Avatar
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Discussion

ATJ Plank Sloper Airfoils for Light Winds


All right guys, several folks have been asking me for this pair of plank airfoils designed specifically for light wind conditions. Till now, they have only been available through FutureSlopeDesigns on the Sherpa http://www.futureslopedesigns.com/Sherpa.html and you can read a bit about their performance on Paige's website. I'm also hoping to get them released on the Zipper at OffTheEdge http://www.offtheedge.com.au but today I am releasing them publicly. Before I do, I'll tell you that I have chatted a bit with Peter Wick about them and here are his words:

"Dear Todd

I compared your airfoils with a PW 1211 with the same thickness and camber.

First of all, the differences in their shape are not very big. The biggest difference is around the nose, where your airfoils are more sharp and have a more pronounced flow acceleration, both on the under and upperside.

This makes these airfoil more suitable for lower RE (good work)
The cm is for the root airfoil a little bit less for your airfoil than for the PW, but will be mostly compensated by the lower RE sensitivity.

At higher (above 250k) Re, the PW`s might have a little edge in sharp corners, producing more lift, due to the more rounded leading edge.

The tip is very very well made, has a more positiv cm, which is also necassary due to the even lower Re there. The cm curve is also very flat.

What I especially like is, as you also pointed out the underside has a very smooth deaccelartion over most of the underside, which makes the underside very stable, concerning laminar flow at lower angles of attack.

So all in all..congratuations good work, especially it is a good strake from tip to root for ships, I would say less than 2m span, but they will also not loose a lot at higher Re.

Yours Peter"


note, this pair of airfoils should be treated as a pair ie. the root airfoil together with the tip airfoil otherwise the span-wise flow won't be as efficient. Also, I do maintain exclusive rights for their commercial use. If you as a commercial vendor decide to utilize them, please contact me first (they are still free, I just want to know what commercial kits are using them).

enjoy, Todd
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Jun 09, 2010, 10:12 PM
Registered User
Thanks for making them available Todd!!!
Jun 09, 2010, 10:30 PM
agony sweetns the victory
atjurhs's Avatar
Thread OP
Your welcome!

They are the results of several months work, using a couple different codes, targeting a very specific niche - plank airfoils for Re numbers less than 80-120K. They've also been tested and perform well up around 250K, but I believe them to be the most efficient airfoils (that current methods enable us to achieve) for that niche. BTW, I've tested them on planforms mimicking the Weasel, the Zipper, and of course the Sherpa flies them, so they are fairly planform independent.

again enjoy, Todd
Jun 10, 2010, 02:56 AM
Long to be flyin'
Antonsoarer's Avatar
Nice foils Todd , Inspiration and acknowledgement??
Last edited by Antonsoarer; Jun 10, 2010 at 08:05 AM.
Jun 10, 2010, 08:35 AM
agony sweetns the victory
atjurhs's Avatar
Thread OP
Yes, I should certainly acknowledge the insight and understanding that Anton provided me in private messages as to what makes a good light wind slope airfoil. You helped educate me, thanks!

Todd
Aug 19, 2010, 11:15 AM
Dark Side of the Red Merle
Curtis Suter's Avatar
Yes Todd!

Thanks so much. I'll give a Zipper flight report with them in the future, perhaps not so near but in the future all the same.

Curtis
Montana
Aug 23, 2010, 06:24 PM
Its not IF... Its WHEN.
The.Timinator's Avatar
Quote:
Originally Posted by atjurhs
Yes, I should certainly acknowledge the insight and understanding that Anton provided me in private messages as to what makes a good light wind slope airfoil. You helped educate me, thanks!

Todd
Perhaps you should have done so up front...
Aug 24, 2010, 01:55 PM
agony sweetns the victory
atjurhs's Avatar
Thread OP
Hey Timinator,

Thanks for the PM, and you're right, Anton freely shared his knowledge and provided me with alot of "knowing what to look for" in my output data in order to produce a good light wind slope plank airfoil.

Also, Paige of FSD inspired me to not develop just one single airfoil, but rather a pair (one for the root and one for the tip) that would work together.

And as previously acknowledge, Peter Wick chimed in with his knowledge, experience, and feedback in the airfoil's development.

I think that just about completes the list of all those who contributed to this project (besides myself).

Hope you all enjoy the airfoils. They do fly rather nicely (but of course I would say that ).

Todd
Last edited by atjurhs; Aug 25, 2010 at 02:11 PM.
Aug 24, 2010, 10:48 PM
FSD
FSD
Definite Flight Risk
FSD's Avatar
Todd is the man...

Todd I emailed you a few weeks ago concerning an idea regarding your outstanding airfoils. Did you receive it?

-P
Aug 25, 2010, 08:21 AM
agony sweetns the victory
atjurhs's Avatar
Thread OP
Quote:
Originally Posted by FSD
Todd is the man...

Todd I emailed you a few weeks ago concerning an idea regarding your outstanding airfoils. Did you receive it?

-P
Sorry Paige, no unfortunately I did not receive your email. I'm rather prompt about that sort of thing. I'll PM with a couple of my addresses just in case one isn't working for you.
Aug 25, 2010, 12:11 PM
Its not IF... Its WHEN.
The.Timinator's Avatar
Cheers Todd
Last edited by The.Timinator; Aug 26, 2010 at 04:56 AM.
Aug 28, 2010, 11:48 AM
FSD
FSD
Definite Flight Risk
FSD's Avatar
Quote:
Originally Posted by atjurhs
Sorry Paige, no unfortunately I did not receive your email. I'm rather prompt about that sort of thing. I'll PM with a couple of my addresses just in case one isn't working for you.
I will...It is not a "dynamic" idea...but one that I am considering once I reopen FSD.

-P


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