On Jan 15, 2:00*am, "Paul Remde" wrote:
:The "Current L/D" window in SeeYou Mobile is very powerful because
you can
:compare it with the required L/D to see how you are doing on the way
to a
:goal. *I remember being impressed with it one day while flying in the
:Minnesota Soaring Club's SZD Junior. *The Junior is a wonderful
glider, but
:it has thick wings and doesn't penetrate wind very well. *I was
fighting a
:20+ knot headwind to get to my destination and could see the
destination
:clearly. *I noticed that my required L/D was onlly 20. *The Junior
can
:theoretically perform at a 35:1 glide ratio, but with the strong
headwind my
:measured "Current L/D" was 12. *I liked that the number was an actual
:measured performance number, not an estimate based on a previously
:measured wind and the entered approximate polar data. *I knew for a
fact that I
:needed another thermal - and I found one. *Cool feature!

It's very interesting that you used the term "L/D" three times, and
every single time it was an incorrect usage. What you were referring
to was in fact the distance traveled in losing a certain amount of
height, or in other words the achieved glide ratio.

And yet the ONE time that you could have correctly said "L/D" you said
"glide ratio" instead!!

A given aircraft at a given weight and in similarly clean condition
will always perform at a fixed L/D (lift/drag) at any particular speed
and G loading. It is an aerodynamic property.

The actual glide ratio achieved will depend on head or tail wind, lift
or sink encountered. As well at the air mass movement it is dependent
on the glider's L/D ratio, but it IS NOT an L/D ratio. It is a glide
ratio.