On Wednesday, June 10, 2015 at 9:07:21 AM UTC-7, SF wrote:
The Speed to fly functionality of the ClearNav vario works pretty well for giving you a speed to fly number based on the current conditions. I don't constantly chase the number it displays, but it is a good number to work off of.


Somehow, suggesting a ClearNav (or even XCSoar) to someone who is talking about making paper speed rings for club gliders doesn't seem reasonable, but I guess I'm behind the times.

For the original poster, Paul Remde has an good assortment of soaring related spreadsheets he

https://www.cumulus-soaring.com/soar...ring_files.htm

In particular, polar6th.xls does pretty much what you want. There is also this web app:

https://www.stolaf.edu/people/hansonr/soaring/spd2fly/

Marc