I fly an SZD 55 and it has a audible stall warning indicator installed.
It consists of a port just under the noes of the glider which is plumbed
into a pressure switch device, it is also connected to the Pitot. The device
compares the pressures and gives a warble when it thinks you are going to
stall. It has an adjusting screw on the instrument panel to adjust the
trigger point. I have not spent a lot of time trying to adjust it so I tend
to leave it off. If on it tends to go off when I am thermalling so I guess I
have not got the adjustment right as yet.
I have not placed it as a high priority for me so have not bothered with it.
However when adjusted correctly I think it would be good.

"John" wrote in message
m...
Can you plumb airflow to an audio variometer in such a way that
normally the vario will not see any airflow, but the vario will see
air flow if the angle of attack is increased?

The idea I have is a stall horn is normally quiet unless you pitch up
and expose the horn to the airflow.

Similarly, a variometer makes no noise on the ground, but does once
you have airflow (rising and descending airflow).

Can we plumb the vario to act like a stall horn? Would be a great
feature during landing. Obviously, would need a selector valve to
switch the varios inputs from the TE probe to the new AOA measuring
source.

One idea is to plumb the vario to a PITOT tube, and bend the end of
the PITOT tube downward at an angle such that normally the end of the
tube is flat to the airflow (essentially, measuring only static
pressure). As the aircraft pitches up, the end of the PITOT would no
longer be flat, and air would enter the PITOT. The vario could then
respond to the changing dynamic pressure.

Maybe the same could be done if the TE probe was removed and the vario
was plumbed to measure "stick thermals" again.

Any thoughts on this?

John