Mark,

My first post came across as a bit glib - apologize for that. But, I
actually put a little thought into that subject recently while writing some
batch analysis specs for GPS log files. The problem is that a good glider
pilot will not encounter random vertical motions - even in cruise flight.
He/she will stack the deck in his favor, seeking out cloud streets or
connecting the best looking individual Cu. Thus, you can't just average
out the L/D over time on specific segments (e.g. cruise flight). What you
can do is deterimine which pilot does the best job of achieving highest L/D
on a given day. Several of the popular flight analysis programs do this
already.

I'd certainly be interested in any detailed ideas you might have.

P3

"Mark Zivley" wrote in message
m...
Obviously ridge flight would not be conducive, nor wave, but put enough
data together from cruises during thermal flights and I bet something
could be put together.

Papa3 wrote:

Mark,

How do you propose to isolate the impact of vertical air motion? For
instance, I can fly the ridge at 100Kts and maintain altitude (same for
wave
or cloudstreets). I'm sure Rolladen-Schneider (ahem, DG) would love to
publish the L/D of my LS8 from the average of my flights for a season:
"LS8, with a measured L/D of 800:1..."

Cheers,
Erik


"Mark Zivley" wrote in message
m...

We all know what the manufacturer's polars look like, but what about our
individual planes. Has anyone done any work to develop a program that
would look at some flight logs and determine what a particular glider's
actual polar is? At one point Ball was making a vario system that would
determine the aircraft's polar over time just by flying.

For someone who already had some algorithms for computing wind from
ground track drift during thermals could take this info and then be able
to back figure from GPS ground speed what the IAS was during a
particular phase of the flight. By isolating longer sections of cruise
flight at varios airspeeds it should be do-able. Question is, has it
been done.

Mark

extra "hot" in the address to delay the spammers...