"john smith" wrote in message
...
73 kts is the stall speed at max gross and aft CG.

Vs(actual)=[sqrt(actual wt/gross wt)]*Vso(gross)


I am not talking about stall speed but it makes sense to me that the
calculation should be the same for the change in glide speed,

so if my best glide speed is 73kts at gross wt (1055 kg), then with just me
and half fuel at about 850 kg
this would give a speed of 66kts, which is a significant difference (
especially from the 75 the flying school suggests)

now that i think about it your equation makes sense. lift required should
be proportional to weight. but lift generated by the wing is proportional to
v^2. So for the same angle of attack it makes sense that the speed should
be a factor of
sqrt ( actual wt/gross wt). in the stall example you are just talking about
a different angle of attack ( 16 degrees) instead of the best glide angle of
attack (4 degrees)

thanks for the help John.

Terry