Airfoil-section stall at low speed

Here's another interesting NACA Technical note:

"Examples of Three Representative Airfoil-Section Stall at Low Speed"
TN 2502

just do a search on "2502" on the NACA archive server.

It includes some discussion on very thin airfoils and describes three basic types of stall.

Searching the NACA archives is like searching the SS Forum archives: one often ends up going down some very interesting "bunny trails"

Thanks. I am amazed that your previous (flap) post didn't get more attention. It was in my view important to a discussion on flat and fixed flaps that we had a few months ago, and of some real practical value.

Concerning low-RN airfoils, the following are also interesting NACA reports: TR 391 (1931), TN 364 (1931), TN 385 (1931), TN 386 (1931), TR 586 (1937), TR 628 (1938), TR 647 (1939), TN 3963 (1957). Igor Burger has posted some good modern stuff on SSW too.

Been there, Done that. I spent many days in the Minneapolis library on a long series of layovers when flying for Braniff back in the late '60's. I quoted many NACA reports in my articles and even pictured some. It was the lack of information on airfoils typical of those we use that prompted me to try to build an airfoil test rig. The NACA reports pointed me toward thicker airfoils and larger flaps.

Yep! And your findings on flap types are mirrored in that report too. The nice thing was that there was quantitative corroboration.

I too thought that the references to the flap report was applicable to the flap discussion as well as the discussions on the Flight Streak fixed flap type airfoil. WRT this airfoils section stall report: I was curious about the use of thin and/or flat airfoils for our stabilizer/elevator. While it certainly shows that the thicker airfoils can reach a higher Cl max than the very thin ones, note how smooth the peak of the Cl/alpha curve is on the thin airfoils at stall (also, note the same effect on the pitching moment). I can't help but wonder if the thin (and/or flat) stab/elevator isn't better for us ham fisted wannabe pilots that tend to apply too much control too late. It might make it easier to fly smooth corners with less tendency to over control while having enough area for good pitch damping??? Also, I wonder if the large negative, smooth pitching moment doesn't give us more feed back (or "feel") at high deflections??? What do you think?