On a clear, breezy day off the coast of California at a spot north of San Diego known as Torrey Pines you're apt to find this young man riding the up-drafts. As one of the nation's youngest solo sailplane pilots, Roger, 14, is a member of that hardy brotherhood which soars on the crest of itinerant air waves that play around the craggy cliffs of the Pacific's shores. He made his first solo flight last November in a Schweizer TG2 four days after he passed the legal minimum age. Member of a family of soaring enthusiasts, Roger learned his love of the air from his father, John Williams, who spends his spare time in such motorless craft or piloting a tow plane for his co-members of the Associated Glider Clubs of Southern California. Roger's best-remembered thrill was soaring across Texas for 300 miles with his dad. A student at Marston Junior High, Roger hopes to become an Air Force pilot but he still has years of work ahead in sailplanes. To gain a rating he must complete a flight of five hours' duration, another one of 32 miles' distance and gain 3,200 feet in altitude in free flight.