Calling all glider pilots, surfers, physicists, and those who are interested in any of these fields of endeavor. Ask Allan your questions in the comments section of this post, and he promises to answer them. Only not when he’s flying, surfing, or doing physics (stay safe, Allan!).
UPDATE: We are no longer taking more questions for Allan. But check out his answers in the comments. He may have answered a question you were going to ask!