On Friday, January 10, 2014 1:10:45 PM UTC-6, Kevin Christner wrote:
My understanding is that modern flight computers (which seem to have 10X more features than anyone could possibly use) don't make adjustment to STF calculations for the wind.

They do make very good adjustments for the wind in the sense that if you dial in MacCready 3 into the wind they will tell you you need a lot more altitude than if you dial in MacCready 3 going downwind.

The speed to fly calculation is not affected by wind, as long as thermals drift with the wind. You still fly MacCready 3 airspeed in MacCready 3 lift. The final glide calculation is also not affected by wind. You still leave a 3knot thermal when you hit the MacCready 3 altitude, corrected for wind.

There are second order effects -- thermals don't drift exactly with the wind, you may be able to bump more or less effectively depending on wind, etc. But it would take a whole new generation of theory and software to begin to quantify these effects.

The optimal MacCready setting is affected by wind, when you're going in to a turnpoint. You want to both fly faster and be choosier about thermals going to an upwind turnpoint, and fly slower and take weaker lift going to a downwind turnpoint. This is currently handled by just increasing or decreasing the MacCready setting, which is what Brigliadori and Kawa are advocating..

The setting choice can be done quantitatively, see "upwind and downwind" here

http://faculty.chicagobooth.edu/john...ring/index.htm

The only thing a flight computer can productively add is this calculation. I've been bugging the CN folks do implement this for a while. All it takes is to present the equivalent after-turnpoint mac cready setting for the current value. But they answer (correctly, from a business standpoint) "we're not putting in a number that only you care about!"

John Cochrane