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Old March 19th 09, 06:33 PM posted to rec.aviation.soaring
The Real Doctor
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Posts: 108
Default Aerodynamics of Towing

On 19 Mar, 16:39, Darryl Ramm wrote:

A glider "climbs" when you pull back on the stick and converts kinetic
energy to gravitational potential energy,


Technically that's a "zoom", not a climb.

The glider also
"climbs" - (maybe you should think of "lifted" if "climb" confuses
you) by a rising air mass and that does increase the glider's
gravitational potential energy.


But people keep telling me that it's conversion of PE to drag which
keeps the glider flying. How can that be happening when the PE is
increasing?

So how many ways do people need to keep answering the same pedantic
question you keep asking?


Well, some accurate ways would make a good start!

It amazes and depresses me how prevalent the nonsensical believe that
"gravity powers gliders" extends in the gliding world.

Do the ultimate thought experiment, turn off
gravity and the glider will just float along with moving air currents
but will be unable to glide anywhere.


Cars won't be able to work either, since no gravity = no weight = no
friction at the tyres. Would you say that gravity powers cars?

Ian

PS Thanks for your concern about my confusion. I don't really go in
for arguments from authority, but would it allay your concern to know
that I have taught and examined fluid dynamics at two major UK
universities for over twenty years?