At 18:24 01 September 2004, Chris Ocallaghan wrote:
I'd always assumed there were two factors in choosing
a pattern speed.
First, safety, thus the +5 for turbulence. The other
was to place the
glider at best speed to fly. That way if you have to
put the spoilers
away, you are guaranteed to cover the maximum distance.
If I recall,
the simple formula for best speed was best l/d speed
plus 1/2 the
headwind. Don't recall the second ever being explained
though. Just
seemed to fit.

It appears that if you draw a tangent to your glider's
polar beginning, not at zero, but at any given headwind
speed, the line will touch the polar at a point that
is best L/D plus half that headwind.