Finding Airfoil Data For Amateur Projects?

An anonymous reader asks: "I am an aerospace engineering student who is engaged in an amateur project. A major hurdle I am having is finding modern airfoil data which can be used for a non-profit project. As most aerospace engineers know, just about all modern airfoil data are guarded industry secrets, so building an amateur project that requires precise airfoil data is difficult, because of the lack of available modern information. There is plenty of dated airfoil data from the 1960s or earlier, but my project requires access to modern data. Note that I do not have access to a wind tunnel to procure this data on my own. Where would one find free modern airfoil data for use in an amateur project?"

Comments

XFoil

[slacy]

There's a great GPL'd program out there called XFoil that contains a large database of standard airfoils, including several "flat bottomed" foils, that are easy to construct from balsa.

I've used these before in some simple hobby projects (that never actually got finished)

Ask the experts

[Rick the Red]

NASA

Coordinate Data and other stuff.

[Skyfire]

Here's a pretty good site with coordinate data. I used it for a Catia model once. If you want data on the performance of the airfoil as well, such as polar curves, here is another site. Anyways, one thing to take note of is that not all modern airplanes use modern airfoils. For example, the Gulfstream GIV uses a modified NACA airfoil.

Sailplanes

[littlerubberfeet]

Sailplanes are a good place to start. Get a copy of "Fundamentals of Sailplane Design" by Fred Thomas, printed by the college park press in MD. ISBN: 0966955307. It has a bunch of equations you are probably sick of (Stokes anyone?) and wing profiles and data for some gliders, including the Eta Uberglider.

If L/D is all you need, it should be easy, though there are some other numbers in the book that are probably useful. Good luck! Also, it never hurts to ask...Have you tried the military? Sometimes they give up random tidbits of data without a FOIA request.

Classic is the best

[Murrow]

The book that I always pull off my shelf is the classic "Theory of Wing Sections" by Abbott and von Doenhoff (ISBN: 0486605868). It's a compilation of NACA data (NACA is NASA's predicessor) and the most comprehensive reference on the subject that I know of. Amazon has a new copy for $14.

I'm not sure why modern data would be a must for any non trans/supersonic vehicle (and some supersonic aircraft still use the classic NACA 4-digit airfoils).

Previous Discussion on this?

[Zapper]

This discussion (Free Hydro/Aero-Dynamic Software Simulators?) has some [maybe] useful links in it.

Totally agree

[rudog]

I have encountered the same lack of current information and airfoil performance. I am a garage-engineer that produces experimental r/c aircraft somewhat regularly.

I have found several gpl/shareware programs that do help design airfoils and predict their usability, but on a small scale for r/c. And the properties obviously change for real-world aircraft.

here are some links that may help though:

http://www.pagendarm.de/trapp/programming/java/p ro files/NACA4.html

http://raphael.mit.edu/xfoil/

http://ourworld.compuserve.com/homepages/Harold_ Gi nsberg/

http://www.compufoil.com

http://www.profili2.com

http://www.ozemail.com.au/~malhardy/

These are applications that I have used with mixed success. And remember - most of these are for model aircraft so YMMV.

Also just google, there are lots of others out there who have run into the same situation and started the own projects to make data available.

Re:Uhh?

[Zeriel]

"Airfoil data" in this context is a summary of performance data over various airspeeds for a given wing cross-sectional shape. There are endless books of these in hard-copy, and they're absolutely critical if you want to design an airframe without having access to a wind tunnel or extensive prototyping facilities.