"news.mcgraw-hill.com" wrote in message
...
During a review of the V-speeds for an airplane I've never flown before,
my
instructor asked me about glide speed vs. weight, and total glide
distance.

I got the glide speed vs. weight part right, but the distance part seemed
counterintuitive - that the total distance covered (by flying at the
correct
best glide speed for the weight) would be the same, regardless of the
weight.

Can anyone explain this so that it makes sense?

Lift/Drag = Velocity/sink rate = Glide distance/Altitude = glide ratio

The angle of descent doesn't change. As the weight increases,
the speed also increases to keep the L/Dmax the same.

Looking at it another way, more weight means a higher sink rate.
To maintain the glide ratio of the lower weight, velocity must
increase.

I just went over this working on my commercial. It doesn't feel right
unless you remember that velocity is allowed to change and the
glide ratio remains constant.