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.