Hi all, sorry if I make mistakes, i'm french. I build gliders and I want can to calculate easily my glider's glide ratio. For all people like me, I've program a little software to simplify calculations.
For calculate your plane's glide ratio, you have to follow some instructions :
1-Select a start point at one altitude (for the example : 3800 ft) and one speed you will maintain during the
measure (here, I take 64 mph)
2-Record the time for reach a new altitude (here, we imagine we stop the chronometer at 2800 ft and I've obtain 3min12s) while maintaining approximately the same speed (in the example, 64 mph)
3-Enter values in my software : the lost height (here, 3800-2800 = 1000 ft), the time to lose that height (here, 3*60 = 180 180+12 = 192 s) and your chosen speed (in the example, it's 64 mph)

The software give you the result at your speed (in the example, we obtain a glide ratio of 18.022 at 64 mph from entered values). This method isn't very precise, the result is an approximation :)
Good fly all ! :)

You can download the software here (Only for Windows) :
-32bits (need java): http://www.mediafire.com/download/0g1hj6vay41gwsx/32Glide+ratio+assistant+calculation.zip
-64bits (doesn't need java): http://www.mediafire.com/download/a19t2u1ducb2u2g/64Glide+ratio+assistant+calculation.zip
Please report bugs, I'm not a professional programmer :,)