How to simply determine the L/D of your glider

On 1/11/2011 7:57 AM, John Cochrane wrote:

It is instructive to compare your statistics for the day to another
pilot flying a comparable glider. I've been surprised at how different
they can be, particularly the number of thermals taken, how fast they
cruise on average, and the percentage of circling times.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

Mean L/D is actually a very poor statistic. 1/ Mean D/L is a lot
better. Seriously now, they are very different. As you go through
lift, L/D passes through infinity and then becomes negative. 1/ Mean D/
L is much better behaved. Now, which one do our computers really
present???

The numbers the OP gets from his PDA, and what SeeYou provides on the
Statistic page, are labeled "L/D", so that's probably why we were using
them. SeeYou also provides "Mean L/D" separately for rising air (it's
negative) and sinking air. So far, no Mean L/D beyond about 80, so
infinity is safe from me!

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)