"Wayne Paul" wrote in message
m...

"Dan D" wrote in message
...

A very 'slippery' glider takes a while for the airspeed to settle down
after a pitch change. Flying to an exact AOA would be easier than
chasing airspeed.

An AOA indicator that shows minimum sink and maximum L/D as well as
stall would be quite useful.


The glider solution could be a simple as the piece of yarn along the side
of the canopy...


It isn't that simple. The string will show the angle of flow relative to
the fuselage, not the airfoil. The fuselage angle of max L/D and
minimum sink change with the flap setting. (Thermal at 15 degrees, cruise
between zero and -10 degrees.)

A true AOA would supply a single given Max L/D indication no mater what
the flap setting. The software to do this isn't difficult if you know
the airflow relative to the fuselage, the angle of incidence of the wing,
and the wing's performance curves for various flap setting.

From my perspective a reliable low-drag encoding vane is the tall pole in
the tent. The airfoil performance/angle of incidence can be derived
from sailplane's handbook. The cockpit indicator can be the
designer's/owner's choice.

Wayne
HP-14 N990
Flap range -10 to +90.
http://www.soaridaho.com/Schreder/HP-14/N990/N990.html

The idea of the string, or the string on each side, is not that that it is a
true angle; but, if the canopy sides are at a promising height and also an
adiquate distance from the wing, that the positions can be marked as
calibration points for the particular angles of interest--such as best L/D
and minimum sink.