"Maule Driver" wrote in message
m...
The best glide speed in the book is calc'd at gross weight. At lighter
weights, the best glide will be lower. The calculation for best glide at
various weights is straight forward but I don't know it. I'm going to
guess
that it will be about 6 knots slower at empty weight plus a standard pilot
(can't wait to find out what the real number is)


See responses above, your 6 kts was a good guess,

Flying that speed accurately is valuable but perhaps not as valuable as
understanding the other major variable in doing an engine out glide to a
spot on the ground. That variable is wind. Since this is a ground
reference manuever so to speak, wind plays a signinficant role. The task
at
hand is generally "best glide speed for distance over the ground". If
you
are flying upwind to a spot, best glide speed will be higher. Downwind to
a
spot, a slower than best glide speed will take you further. Accurately
flying 73 knots to make maximum distance over the ground into a 20 knot
headwind is a mistake. (I'd guesstimate that 80-85 knots would be more
like
it).

excellent point about the wind, i can make sense of that, spend less time
going against the wind.



I don't know the formula for doing the calc and doubt you will have it if
faced with the problem. When faced with the problem, I had a gps driven
glide computer in my glider which would give you precise guidance based on
wind, glide polar, and vertical air motion.

I dont intend to be doing the calcs on the spot but to have some numbers in
the back of my head for different wts. I always have a fair idea of what my
wt is at any time.


A couple of rough rules of thumb
- err on the high side for upwind max distance glides - you really need to
go faster upwind and there is disportianate penalty for being slower than
optimal
- err on the high side for downwind - you can get a little more distance
by
going slower than best glide speed, but not much. Just fly best glide if
in
doubt

I'm really interested to see what the actual speeds are for different
weights and wind conditions.

Im interested in the wind calcs too now. thanks Maule. by the way what is
this Maule thing that you drive?

Terry