On Tuesday, February 7, 2017 at 9:42:02 PM UTC+3, wrote:
Sounds like you are trying to find a use for stuff in the instruments.
My question would be what are you trying to accomplish?
UH


Goal: To increase the pilot's awareness of how close to the stall the aircraft actually is. This could be of some use during thermalling flight, especially at low level or when encountering gusty conditions. A poor man’s AOA meter, if you will. If properly implemented, it should help avoid stall/spin accidents... I believe that aircraft landing on carriers carry such technology (AOA indicator), as well as certain business jets. Before the days of microprocessors, this would have been difficult to implement. See Soaring magazine, March 1975 to give you an idea of pre-microprocessor attempts to do this.

Since many modern varios already have sensors receiving and interpreting the required inputs to calculate CL, it should be simply a software modification to actually calculate this value. Perhaps the most difficult part of the whole implementation would be to present the pilot with this information so that it would be useful to him (Visual? Audio?).

Having to input weight and wing area (which admittedly doesn't change on most gliders) before flight seems like not only a pain and error-prone but also not entirely useful as different wing profiles have different useful max CL as well, and that is not published information even for "as new" gliders.

Maybe better to do an in-flight calibration where the pilot flies the glider briefly at their personal comfort limit near the stall and presses a button to calibrate the instrument. This could be done in straight and level flight, with the pilot judging it by buffet, sink rate, sound from airflow breaking away from the wings or whatever. Or it could be done in the first in-anger thermal.

Maybe also have "+1 knot" and "-1 knot" buttons to fine tune it later.