Ian wrote:

Think of a slinky spring going down stairs.

Now think of a slinky spring going down an "up" escalator.

In short - nothing fancy happens to the angle of attack. The glider
keeps on going down through the air...

....and, when the air is going up faster than the glider is going down,
then the Glider goes UP. Or, thermal air rising 400 fpm - glider sinking
100 fpm = glider climbing at 300 fpm.

Angle of attack changes only momentarily, while in the transition phase
from the glide in still air to a glide in rising air, in order to
accelerate the mass of the glider to a state of equilibrium within the
rising air mass--assuming a constant airspeed.

If entering a strong area of rising air both the angle of attack and the
airspeed may increase initially but both return to equilibrium as above
without pilot input.


Jack