On Sun, 30 Nov 2003 16:51:58 -0800, Holger Stephan wrote:

Kevin Horton wrote:
Note 2: the glide ratio does not vary with gross weight. I won't try to
explain the math or physics as there are lots of references available on
the web for your googling pleasure.

True only in theory (i.e. on high performance gliders). The added drag
with the increased max glide speed will decrease the ratio.

- Holger

The higher speed also gives more lift, and the lift to drag ratio (and
hence the glide ratio) remains the same. This assumes that both
conditions are at the same angle of attack, and the the changes in
Reynolds number and Mach number don't change the airfoils CL and/or CD.
This should not be a problem with typical light aircraft at their best
glide speeds at typical light aircraft altitudes.

But, if we have a windmilling prop, the windmilling rpm will go up
with speed, and the windmilling drag could increase quite a bit, and that
could affect the results. So, add an assumption of a stopped prop.

--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://go.phpwebhosting.com/~khorton/rv8/
e-mail: khorton02(_at_)rogers(_dot_)com