On Saturday, February 8, 2014 11:30:34 PM UTC-5, Waveguru wrote:
Gravity does not power our gliders. The forward tilt of lift is what moves us forward. The sun powers our gliders. ( after the initial boost from dead dinosaurs)

Pointing out that the sun is the source of all vertical wind is a good way to recruit young eco-minded prospects, but some folks will be put off by that "sustainable green talk".

My standby line is that "a good glider pilot can stay up for hours without spending any money on fuel". Most people take that as a big plus, and it directs the conversation towards lift and the core challenges of flying gliders.