Airfoils S822 or better?

[DanOpto]

Has anyone used the S822 airfoils to build a wind generator.


Are they worth the extra work in building their special shape.


Are there better or newer airfoils to use for a wind generator?>br>

Where is the best place to look for the best airfoils?

[Dutch]

Every airfoil has it's own characteristics and there isn't such a thing as a "bad" or "good" airfoil. Given a specific situation (drag, lift, speed, rpm, windspeed, etc.) some airfoil is more suited then another.

The standard book about airfoils is Theory of Wing Sections from Abbott and Von Doenhoff. This book has a rather steep learning curve and you kan better start with more casual stuff.

Have a look at my website http://www.windwerk.nl/modules/mylinks/viewcat.php?cid=8 for some valuable links on this subject.

And this is a nice primer http://www.dreesecode.com/other/aflprimer.pdf

Have fun ;-)

[finnsawyer]

I don't see an advantage over a NACA 4412.  The lift and drag coefficients seem to be similar.  Keep in mind that a thicker blade means more weight and the problems that flow from that.  Also unless you're bound and determined to approach the magic 60% efficiency I'd also just do a flat windward side.  Why use more material than you need?  I guess I'd like to see efficiency curves for actual mills made using these blade profiles.  I wouldn't do it myself.  

[Victor]

Hi Dan,

 Where did you find this info?

Victor

[DanOpto]

http://wind.nrel.gov/designcodes/papers/NREL%20Airfoil%20Families%20for%20HAWTs.pdf

http://www.nrel.gov/docs/fy99osti/26173.pdf

This is interesting research comparing several different airfoils on a wind generator.

I was looking at these pdf files from wind energy research and I was interested to find out if anyone was using them for homebuilt rotors.

Would anyone with experience with these please give their opinion

[cslarson]

I also came across these profiles (NREL S822 and S823) when researching airfoils specific to wind power generation.  I think the article (http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=212729) was highly relevant also.  The full pdf should also be available at some point from http://www.cprl.ars.usda.gov/REMM_Publications.htm.  These airfoil profiles were designed specifically for small wind turbines (1KW - 10KW) back in 1993.  My understanding is that now both Southwest Windpower Skystream (http://www.windenergy.com) and Endurance Windpower (http://www.endurancewindpower.com) are using them in their blade designs.  When made from wood, though, I can understand that they would significantly increase manufacturing complexity.  I'm hoping to only have to make one from wood which I will then use as a plug for a fiberglass mold.

I'm building wind turbines in Kabul, Afghanistan with the eventual goal of encouraging a small sustainable wind power industry (our project was instrumental 20 years ago in developing the micro-hydro industry here - arguably much better suited to the country than wind, sure).  We have a wind map now, though, and the improved power profile these airfoils offer may make a significant difference to the utilization of wind here.

Could anyone help me determine what would be an optimal chord width and pitch angle?  I am hoping to basically duplicate the blades from the article mentioned above.  They were 1.67m long and produced maximum power of 1.5KW.  The S823, thicker airfoil, is used for the root section, up to 40%, while the S822 is used for the remaining blade section.  According to the article they had a linear chord taper, and "a near Glauert twist distribution" (I haven't been able to find out what this means!).  Any help would be greatly appreciated and certainly help speed things up for us (I am admittedly a real novice with these aerodynamic issues).

Thanks in advance,

Carl Larson

RESAP Engineer, IAM