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)

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).

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.

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.

"d&tm" wrote in message
...
the best glide speed of a warrior is quoted as 73 kts. but best glide
should
be at best lift /drag ratio which I recall is at about 4 degree angle of
attack. But this must be a function of weight. So my questions are what
weight is the 73 kts based on ? and how much does this best speed change
say
between maximum weight and minimum wight , or lets just say an 80 kg ( 176
pounds for the folks up over ) pilot flying solo with half fuel? Why ? I
am just curious, I like practicising my forced landings ( solo) and just
wondered how much extra time /distance i might get by flying at a more
"correct" speed. My flying school actually rounds it off to 75kts,
regardless of weight.
Terry