On Thu, 30 Dec 2004 16:51:25 -0800, Eric Greenwell
wrote:


GPS speed and pressure altitude are referenced to the earth, not the air
mass, so they would determine a different L/D than airmass referenced
instruments. In concept, a glider flying at constant speed through
rising and falling air would have a constant L/D according to the laser
airspeed sensors, but a widely varying one based on GPS speed and
pressure altitude.

You are correct - I should have read your posting more carefully!
Happy New Year, btw!


Bye
Andreas