Affects of Critical Alpha on Mach number
 

Does the maximum AoA vary with mach-number?

If you mean the AoA for maximum lift - yes, it varies with Mach number.

regards,
HN39

P.S. NACA Technical Note No. 1390 shows effects of Mach number on lift coefficient, pressure distribution, AoA, etc. Another illustration is shown in Boeing Aero Magazine no. 12 .

Also,
 

Dont forget flying control reversal tendency at or around Mach 1. Miss Jane.

UA

Try this link, near the end is a graph of CLmax vs mach number for the DC9.

High Lift Systems: Predicting CLmax

You can see that the maximum coeficient of lift decreases above about M 0.3.

This is one of the reasons why indicated stalling speed (CAS) increases with altitude (the other being compressibility error).

Rivet gun;

Thanks for the link to an article containing a wealth of interesting data. Could you indicate the source of the article?

In the graph of CLmax vs mach number for the DC9 (no flaps, no flaps), I note that CLmax increases between Mach 0.8 and 0.9 . That seems somewhat odd and I see no reason for it. Can you explain it?

regards,
HN39

Hazelnuts
Maybe because it is labelled tail off from flight test ???? http://images.ibsrv.net/ibsrv/res/sr...ies/thumbs.gif

Seriously, it might be just the flight test value, which could be buffet limited rather than a genuine stall, and an estimated correction for tail load which might or might not be credible.

Source I think is the course notes for Stanford University AA241

Does this trend of critical AoA reducing with mach number increasing continue when going supersonic?

I'm just curious because if I recall supersonic airflow can go very rapidly around rough edges (and from what I remember this is why you can use an airfoil with a diamond cross-sectional shape at supersonic speeds), though on the other hand, you have a shockwave on the leading edge that you don't have on a subsonic wing and that does tend to produce some turbulence behind it and that could make airflow separate a bit easier...