motorgliders as towplanes

All of the energy to maintain a glider in steady flight through still
air is derived from gravity - there is no other source of energy.

Potential energy of the glider is converted to kinetic energy in the
form of forward motion in order to overcome drag. In a 1000 lb
sailplane with a 40:1 glide, the wings will develop about 25 lbs of
forward thrust to overcome drag and about 1,000.3 lbs of total lift.
The glide angle is about 1.5 degrees.

I don't understand why people have a problem understanding this - it's
a very similar problem to a ball rolling down an inclined plane.

Just basic physics!

Mike

On 17 Mar, 18:33, Mike the Strike wrote:
All of the energy to maintain a glider in steady flight through still
air is derived from gravity - there is no other source of energy.

And how often do we fly in still air? For that matter, how often do we
build gliders on the top of hills, fly them to the bottom and then
abandon them. A very little energy may be stored as gravitational
potential, but gravity certainly isn't the source of the energy!

Ian