USA 35B airfoil experimental data 4

[gibran_alves]

Hello everyone, I need of experimental data from USA 35B airfoil, is to an academic work (homework). Where can I find experimental data from this airfoil? I tried airfoiltools.com (I find the airfoil I want, but not experimental data) and others coordinates sites. Or if is not possible what can I do to get these data?

tnx for reading

 

[rb1957]

1) see the "students click here" on teh LH side of teh screen.

2) why do you want the experimental data, if you can see the resulting curves ?

another day in paradise, or is paradise one day closer ?

 

[3DDave]

Try contacting UIUC aerodynamics group for data.

https://m-selig.ae.illinois.edu/

 

[verymadmac]

Have a dig around on the NASA tech sever maybe

https://ntrs.nasa.gov/

 

[gibran_alves]

Hello everyone! I find the experimental results that I need, tnx a lot for your tips

@rb1957 -> about the 2nd question: my teacher ordered us to get experimental data (that's why I'm suffering to find these data) would be ease if I could use xfoil to get these data after this I'll curse the teacher (I'm kidding if teacher is reading this).

@3DDave -> tnx for tip, I'll search this

@verymadmac -> I found the data just there, tnx for the tip.

Now I have a problem, if some of you could help me, the experimental data is quite different of xfoil results, I dont know hot to solve it.

 

[Sparweb]

Now I have a problem, if some of you could help me, the experimental data is quite different of xfoil results, I dont know hot to solve it.

The methodology you need to model an airfoil's characteristics can be found here:
Theory of Wing Sections (Dover Books ) by Ira H. Abbott, A. E. von Doenhoff

https://www.amazon.com/Theory-Wing-Sections-Aeronautical-Engineering/dp/0486605868

Or
NACA-TR-824, 1945, Abbott, Von Doenhoff, Stivers, Summary of Airfoil Data

Which you can find on the site above.
For clarity, NACA is the precursor of NASA.
There are no typos in my post.

Edit:
You use experimental data to validate the aerodynamic model. XFOIL is also a model. If you build either model incorrectly, then the results won't agree with experiment. In either case, the model loses because the experiment, when well constructed, is closer to reality than any calculation.

I have to agree with RB1957's point: if you're a student then whey are we teaching you this instead of your professor??

 

[rb1957]

would Abbott and von Doenhoff (my uni aero text, from a lifetime ago) have the raw data ? or the results curves ?

if your teacher asked you to find the raw data then either ...
1) he knows it's out there and is seeing if you can find it, or
2) he doesn't know it's out there and is being a jerk !?

I'd try the olde NACA reports ... there was a mirror site in Cranfield some time ago. I remember that they tightened up access to the Langley library.

But seriously, do read "students click here".

another day in paradise, or is paradise one day closer ?

 

[3DDave]

Huh.

The EAA sells a book (about $20) called GA Airfoils written by Harry Riblett which is a very informative book that the average aviator should have no problem understanding.... and it's a lot easier read than Abbott and Von Doenhoff's book: The Theory of Wing Sections. I've read and utilized both and Riblett has his stuff wired. The USA35B is a good airfoil, no question about it. The Riblett GA30A613.5 should be just a tad bit better. Don't see how one could go wrong with either airfoil. I have Compufoil loaded in my computer and with it I can overlay two airfoils on top of the main airfoil. Quite an eye opener. I'm using the Riblett GA30A613.5 on my little bush plane project. Bob Barrows chose the Riblett GA35-413.5 for the Patrol which worked out pretty well from the reports I've read. The 4 series has lower Reynolds #s than the 6s so don't know how it would compare side-by-side with a Cub of similar weight/power. Heard rumors he had the Patrol at a STOL contest recently. Wonder how it did?

https://www.supercub.org/forum/showthread.php?36076-Why-USA-35B

Also of possible interest:

https://www.supercub.org/forum/attachment.php?attachmentid=10906&d=1365107996

(from the same thread)

 

[rb1957]

but will these reports have to original raw test data the OP is looking for ?

another day in paradise, or is paradise one day closer ?

 

[LiftDivergence]

Now I have a problem, if some of you could help me, the experimental data is quite different of xfoil results, I dont know hot to solve it.

Possibly because Xfoil is intended for low Reynolds number computations.

What range of Re are you interested in / trying to compare?

Keep em' Flying
//Fight Corrosion!

 

[LiftDivergence]

Also, looking a bit further...

I tried airfoiltools.com (I find the airfoil I want, but not experimental data)

Not sure what happened there, but I found it straight away:

http://airfoiltools.com/airfoil/details?airfoil=usa35b-il#polars

Halfway down the page you can change the reynolds number range and Ncrit to show different plots.

There is also dat included in NACA TN-219:

https://ntrs.nasa.gov/citations/19930081027

I got the selig format dat file and ran some calculations in Xfoil for Re = 500,000. I only did a AoA range of 0 to 8 degrees but it seems to match up perfectly with the data on Airfoil Tools.

So we know at least the computational methods are being consistent.

You are right that there is a bit of discrepancy in the test results (at least in the report that I linked to). But I notice the plot in the figures was made for a Re = over 3 million.

I would make sure your Reynolds numbers are consistent when comparing.

Keep em' Flying
//Fight Corrosion!

 

[gibran_alves]

@LiftDivergence the reynolds number I'm trying is 3.47 * 10⁶, what type of flow are u using: inviscid or viscous?

@rb1957: the idea of work(s) is first to get experimental data and after use simulations tools like xfoil, ansys (main tool) to generate simulated data and compare the results. And I got the experimental data

and first, sry for the late reply and tnx for the answers