pman, believe me, it's a can of worms. I've been thinking about it for years and gotten to succesive explanations, only to reject each as incomplete and sustitute for the next one.
Lift is generated by your speed RELATIVE to the wind. Not by your ground speed. You're flying supported by the wind that surrounds you and move with it and inside it. Imagine a fly flying inside a railroad coach, it´s going perhaps a hundred MPH relative to ground but quite slow relative to wind. So the lift doesn't depends on how fast the train is going. OK?. But in ridge lift, wind goes up forced by the ridge in the windward side, so if you fly there you can stay aloft while the wind goes up relative to ground faster than you go down relative to wind. Your wind speed indicator is relative to wind,
while your altimeter is relative to ground, and anyway you can see the vultures flying next to you. As you fly away from the ridge, the ridge lift diminishes, so if you keep your flying speed constant, your sink ratio is constant and you must go down proportionally to the ridge lift loss. When circling on ridge lift, just the opposite happens. Away fron the ridge you go up, towards it you go down. Of course speed relative to ground changes, being lower while going away from the ridge. Now is when it starts getting rough. If you're interested enough, email me, my address is in my profile. Perhaps we can figure it out. Strange things start happening when you leave the ground...same as when you drink too much CruzCampo.
- Chotacabras