When I say that flaps have non influence on stall AOA, I shoud have said 'simple flaps'... For the same reasons as leading edge slats, slotted flaps are another story... But the only glider I'm aware of with slotted flaps was the Breguet 904... That's history but I will never regret the day I had one at disposal...

Basically it is a question of definition:

If you consider that the AOA is the angle between the tip of the leading edge and the trailing edge, then the critical AOA will decrease with flaps down... But that's not what we measure... We measure the angle of the fixed part of the wing and unless you have a variable incidence this angle is the same on the fuselage or on the wing.

When I say that flaps position has no influence on the best glide angle or maximum lift angle, it assumes also that I consider low flaps deflection, say +- 15°... This might not be true for 45° flap deflection or more as this will modify the airflow regime considerably, create a lot of turbulence on top and new stagnation points under the profile... Indeed it will lower the critical AOA (as measured).

Same for critical stall angle... Stick a sidestring on a flapped glider and check for any flaps position, and stick some colored tape at stall angle! Wind tunnel experiments or calculation shows that we are within 1-2°.... Over a 25° range. This is sufficient to say that it will make no difference in flight...compared for example to stall speed in various configurations. And if we suppose that the pilot is sufficiently skilled to keep the right flaps settings it makes no sense anyway... And the AOA indicator is a precious instrument to set the flaps at the right position anytime.

As I said on a previous mail, I'm designing a detachable indicator... Dimension will be about 10x50x8 mm with a back connector and it might be integrated in the panel or simply stuck over the surface... I think to integrate it into a 80 mm ASI... I have a spare... And don't forget that the data will be available in any suitable format for your calculator to have something displayed there... Next step is to integrate this into XcSoar... Next winter?

And to anticipate the next remark: My system is not designed to work in inverted flight... But it is possible to setup a second one with a top pressure port for this purpose.