Until I read the book 'Ruder and Stick' I thought you can not hear the
AoA. But now I know that I can hear large changes in the AoA. Just turn
down the radio and the variometer and listen to your glider when you are
flying at different AoA at the same speed. You will realize marked
differences in sound of your gilder. Our Duo sounds different at
thermaling AoA and at stall AoA. The sound at stall AoA is much deeper
than at thermaling AoA.

You can feel the distance to the stalling AoA in the elevator. If you
are far away from the stall AoA a small increase in back pressure on the
stick will lead to a much larger change of the attitude than at an AoA
close to stall speed.

Unfortunately we train our students in practical flying for attitude
controlled flight. This is a very successful strategy to reach an
intended equilibrium speed in calm air if a slow control loop is
sufficient to reach the equilibrium. But it is not a very good technique
to fly in the turbulent air close to a ridge. There as in winch launch
we train to rely more in the ASI, but again this is just a successful
technique, if a slow control loop is sufficient to reach the equilibrium.

It would be much better to have a fast AoA in the glider and to use it
in the control loop, because it would tell you all the time how far you
are away from the stalling AoA.


Eric Greenwell schrieb:
Bill Daniels wrote:

Controlling airspeed is simply not good enough - it's too abstract,
too easy to triviallize, too easy to misunderstand the significance of
it.

snip

As pilots, we do not fly the cockpit, the fuselage or the empenage -
we fly the wing. The wing is really the only thing that does fly, the
rest is just baggage.

While I agree with Bill that stalling the wing is a proximate cause of
stall/spin accidents, I don't understand his conclusion that getting
pilots to understand angle of attack (AOA) will help a lot (or even at
all). The big problem is AOA is an abstract engineering parameter,
because pilots can't see it, can't hear it, and can't feel it. We can
see attitude and airpeed, we can hear airspeed and stall rumble, and we
can feel stick position and stick forces, so that is what we use to fly
by. I sure don't think about AOA when I'm flying.

IF we had a "good" AOA indicator or pre-stall indicator, THEN we might
be able to fly more safely using it. And that is something the soaring
community has wanted for decades, but so far, we don't have any in wide
use. So, I think we need people to experiment with currently available
AOA units, like Safeflight's and DG's. If they seem useful, try them on
students, and see if students learn fly more safely or more quickly. If
AOA indicators seem promising, it might lead to better/cheaper
indicators, and begin to spread throughout the fleet.

Until we can hear it, see it, or feel it, we won't be able to use.