Soaring is essentially like sailing in 3D. You are using the power up
updrafts, whether caused by heating of the earth (thermals), or winds
blowing against mountains (ridge lift and mountain wave) to provide the
power to stay aloft. The basic aerodynamics are the same as in a power
plane with the engine turned off. The big difference is that sailplanes
have much better glide ratios due to their much wider wingspans and the lack
of drag provided by an inop engine.

Mike Schumann

"Allen Smith" wrote in message
...
Hello,
I just watched a movie online (Youtube) about gliders and saw one
thermaling and gaining altitude. How is this is done? I am a presolo
power pilot (Just finished with my 12th hour) and have been taugt
that a power plane will climb when excess power is availible.
(Steepen the angle of attack, and the airplane will start climbing
steady when all 4 forces are equal) How does a glider do that, since
there is no engine? Does the thermal change the relative wind?
(Which can\'t because the airplane creates the relative wind as it
flys through the air, right?)

Really interesting stuff.





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