It isn't hang gliding but Carl was present quite regularly at our early Southern Cal HG gatherings. We all enjoyed his company and got to know him well, considered him a friend, and of course enjoyed his films and still photos. I have a group of poster sized prints, of the early HG flying, that he gave me.
CNN is running a documentary about his starting BASE jumping history. It airs this evening (Sunday 1/17/16) at 9:00 PM PST. The title is "Sunshine Superman".
Frank C.