>How can you determine in flight, the best angle of
attack for best glide?  Can that be guestimated from your angle of attack
instrument?<

When you are flying in the green of the AOA you are in "normal command" and
when you are in the yellow or red  you are flying in "reverse command."
Normal command means that you are flying in a regime where adding power
will result in flying faster assuming you leave everything else alone.
Flying in reverse command means that to fly slower will require more power.
 Reverse command is sometimes called flying on the back side of the speed
stability curve or behind the power curve.  I think Scott would call it
flying on the "dark side."  In any event, the transition between normal and
reverse command is L/Dmax or best glide.  It is also where the induced +
parasitic drag is at a minimum.  On the AOA gauge it is where the display
transitions from green to yellow.

So, to fly at the best glide using an AOA instrument, fly the transition
between green and yellow and be assured that no mater the GW, CG, bank
angle, etc. the IAS will be correct.  Of course this assumes your AOA is
calibrated correctly.  To confirm, refer to any one of the recent articles
in Sport Aviation on test flights for best glide.

There was also a lenghty article on L/Dmax testing in the Lancair Network
News and is available in the archives.  Search for Best glide.    

James B. Frantz
Proprietary Software Systems, Inc.
www.angle-of-attack.com
LFrantz@compuserve.com
(952) 474-4154