Polar Analysis from flight logs?

At 22:30 30 December 2004, Eric Greenwell wrote:

A Google search turned up laser airspeed sensors that,
in concept, could
be used to measure L/D directly from the glider. Some
of them were good
for the low speeds we need to measure sink rates. So,
have one pointing
forward, one pointing down, divide the forward speed
by the sink rate,
and ta-da! L/D.

Would you need an inertial platform to resolve horizontal
and vertical accurately enough or would eyeballing
it be good enough?

Also, the forward looking and downward looking lasers
would be observing different air, so it's possible
that would cause problems, depending on how far out
they look.

I think it might work - though at a hefty price I bet.

9B