National Geographic : 1967 Jan
Sailors of the Sky that still stands. Actually, his ship was still in strong lift, but he had reached the limit of safety without pressurization. Someday, someone will build a pressurized sailplane and reach 60,000 feet or more. No one knows how high such waves go. "Twenty years ago, we didn't know much at all about mountain waves [painting, page 66]. Just that they contained fantastic vertical currents that could send an airplane shooting upward at 3,000 feet a minute-then send it plummeting down again. Such turbulence has peeled the wings from a fast-moving powered plane. "In 1949 the Air Force, the Navy, and the Weather Bureau launched a three-year proj ect to investigate the Sierra Wave. They used instrumented sailplanes as research tools. Because of their light weight and slow speed, sailplanes are well suited to probing turbulent air. They can ride the very wave currents being studied and measure them more simply without engines." Gliders May Bring Men in From Space Mighty mountain waves, surging desert thermals, cold fronts shoveling warm air aloft as they sweep across the country-pilots in the United States can choose from a wide range of soaring conditions. NTING BY DAVIS MELTZER:EKTACHROMEBY EMORY KRISTOF N.G .S.