Best Glide is one of the
cardinal speeds which it is important to know when flying a
glider of any kind. Max glide, as it is also known, is the speed at which the
aircraft gets the best glide angle, i.e. the greatest
horizontal distance for a given loss of
altitude (in still air). This is the
airspeed at which to fly to
maximize distance across the ground, and also the best
speed to fly when flying
upwind (all else being equal).
For a typical
hang glider,
stall speed is 18-20 mph,
minimum sink is about 21-22,
trim speed is 22-24, and
best glide is somewhere in the 25-30 mph range. Flying at best glide speed will put one on the ground sooner than flying at
minimum sink speed, but one will cover more distance across the ground. One must use careful judgement when determining which is more desirable.
These airspeeds can be determined using
instruments while flying in still air and recording airspeed vs. descent rate. A
plot of these values is called a
polar curve, and is an indispensable aid
to pilots when racing or trying to maximize any aspect of gliding flight.