[Crumpp]

So are you suggesting aircraft can't turn without thrust?......so every glider I have seen change direction is purely my imagination?

Now we have to teach people the basics.

Aircraft cannot sustain performance without excess thrust and the forces in balance.

Any airplane without excess thrust can use gravity and momentum to achieve instantenous performance.

A glider uses gravity to propel itself which is why we don't use them on transatlantic flights. They exist in a purely instantenous performance condition. They cannot sustain performance under the power of gravity alone and must constantly trade altitude for airspeed without an alternate form of energy.

Gliders seek an alternate form of energy in the form of rising air currents to stay aloft.

Flying a sailplane is probably the closest thing any human will come to feeling like a bird. Powered only by gravity and air currents, these gliders move silently through the sky, often for hours at a time.

http://www.mansfieldct.org/Schools/M...ightglider.htm

Bongodriver, try to make a turn from maximum level speed in an airplane maintaining both airspeed and altitude.