RAE2822 - experimental lift coefficient
 

Does anyone know where I could find lift/drag/moment coefficient data for the RAE2822 airfoil? I have pressure coefficient data, but it would be nice to compare with test data for the integrated lift coefficient (I don't know if it was even measured).

I'm specifically interested in Mach 0.729, 2.31 degrees alpha.

Thanks in advance.

Re: RAE2822 - experimental lift coefficient
 

Look at this:

http:/www.grc.nasa.gov/WWW/wind/valid/raetaf/raetaf01/raetaf01.html

Bye

Re: RAE2822 - experimental lift coefficient
 

Thanks, I am aware of that site. In fact that's were I obtained the pressure coefficient data.

To repeat, I am interested in the section lift coefficient from the test.

Re: RAE2822 - experimental lift coefficient
 

If you cannot get a hold of the AGARD report that's referenced on this website, why don't you digitize the experimental Cp data on Fig. 7? If you need a nice digitizer I am sure we can recommend one. Integration to obtain Cl shouldn't be a problem.

Re: RAE2822 - experimental lift coefficient
 

I have considered that (a numerical integration), but I thought it would be best to compare to actual test data if possible.

I don't suppose you have access to the AGARD report?

Re: RAE2822 - experimental lift coefficient
 

No, I would have given it to you if I had. But you can be pretty sure that any Cl quoted in the report will be just that: An integration of the measured pressure coefficient. That seems to be your best option and is usually very accurate, especially with such a nice resolution as provided in this case.

Re: RAE2822 - experimental lift coefficient
 

Thanks anyhow.

I had browsed many citations of this popular test case and not once did I come across a comparison with the integrated force/moment coefficients, which is what led me to post here.

I'll have to see if I can get hold of the original report.

Re: RAE2822 - experimental lift coefficient
 

You should definitely try to get the original report.

But, aside from that, you didn't get my point. Taking the integral over the pressure a very common (if not most common), accurate and established technique to obtain a steady-state lift coefficient experimentally (alternative to a scale). It's likely that that's exactly what is provided in the AGARD report, anyway. I say "likely" without having seen the report, because it's hard to believe that anyone would go through the extra trouble and expense to use a scale, when the surface pressure has already been obtained at such high resolution.

In any case, the resolution looks high enough to get a very accurate lift coefficient that should closely match any scale, and the integration is really easy to do. In fact, you could have done the digitization and integration in the time we both spent on writing posts about it (if you're a slow typer like me). ;)

If other people quote comparison's with the "experimental lift" you still don't know if it was obtained from a scale or from the pressure data, unless they specifically mention that (unnecessary) detail. Typically it would be from the pressure.

Re: RAE2822 - experimental lift coefficient
 

Without seeing the report, it's also possible that the section lift coefficient was measured with a strain gauge or balance, which would give a more accurate result than a numerical integration of the discrete pressure coefficient distribution at the surface taps.

Your point is taken, but that's why I'm hesitant to just go ahead with the integration.

Anyway we've ordered the report and will hopefully see the "truth" soon enough....