National Geographic : 1946 Sep
New Frontier in the Sky BY F. BARROWS COLTON « C MPOSSIBLE' is now an obsolete word!" SSo said three scientists to me one 1- day at the great Army Air Forces re search center at Wright Field, Ohio. That is the guiding watchword of the men who today are rapidly opening up the newest, strangest frontier of the earth, high in the vast, cold, blue depths of the sky. This new frontier lies overhead in the "ocean of air," the atmosphere, which envelops the entire globe as the skin envelops an orange. It extends from the surface up to a height of perhaps 600 miles, to the very top of the atmosphere, where the last few scattered mole cules of air merge into the vacuum of outer space. Most of us, up to now, when we thought about geography, thought only of the land and sea and did not include the atmosphere. But today the Age of Flight has given geog raphy a new third dimension-upward. You've heard a lot about aviation, but probably not so much about the ocean of air in which it operates. This ocean of air, this new world aloft, is fast becoming as important as the ocean of water. Things are happening in it that will affect your destiny and mine as much, perhaps, as anything down here below on terra firma. Heroes of Sky Exploration Until recently nobody knew much about the ocean of air except for the first few miles above the earth, where weather and storms originate and circulate.* It was only a little over ten years ago that daring explorers began to pene trate higher and Captains Albert W. Stevens and Orvil A. Anderson (now respectively Lieutenant Colonel, retired, and Major Gen eral) made their historic stratosphere flight in the National Geographic Society-U. S. Army Air Corps balloon Explorer II, reach ing a record altitude of 13.71 miles.f Today, with rocket-driven missiles such as the V-2 bomb climbing five times that high (pages 384-86); with radar signals being sent to the moon at frequent intervals (page 382); with world-wide wind belts being charted for the use of airline routes as carefully as ocean currents are for ships; with jet-propelled air planes crossing North America in four-and-a quarter hours, and 1,000-mile-per-hour planes predicted, the ocean of air has acquired a new and urgent importance (page 396). We're finding strange things in this new world overhead. To penetrate it, to learn to live, work, travel, and fight in its upper depths, man has to overcome barriers and diffi culties unlike anything ever encountered by earth-bound explorers. Queer behavior of the air around an airplane when it nears the speed of sound is one mystery of the ocean of air. When Maj. Fred Borsodi of the Army Air Forces put a new fighter plane into a high-speed test dive from 40,000 feet, he was startled to see a strange ripple moving steadily across one wing. When he reported the occurrence to his com manding officer, the latter only smiled and said, "Fred, those dives are pretty strenuous. Better take a little leave." But, later, motion pictures of these mysterious ripples were ob tained (page 405). Those pictures were the first visible evidence on an airplane of the strange phenomenon of "compressibility," a very real barrier in the sky. As intangible as a gust of wind but as "solid" in its way as a stone wall, it has pre vented airplanes from flying faster than the speed of sound. When Airplanes Vie with Speed of Sound It so happens that when an airplane reaches the speed of sound, 661 miles per hour in the -67° F. cold at 40,000-feet altitude, particles of air cannot get out of its way fast enough to flow smoothly over the wings and provide "lift" in the usual manner. Instead, they form "shock waves" that bat ter at the airplane structure, spoil its lift so that it may fall out of control, and even may tear off parts of the plane. Those shock waves were what Major Borsodi saw and photo graphed on his airplane wing. High over the Japanese islands, at 30,000 feet, our B-29s ran into terrific head winds blowing 300 miles an hour, stronger than any winds ever encountered before by our bombers. These winds caused some of the B-29s to fly backwards at times, since they blew faster than the B-29s' own forward speeds. In the cold, rarefied air at 63,000 feet a man's blood literally would boil because of the reduced atmospheric pressure if he flew to that height without protection. At 40,000 feet a breath of fresh air is any * See "Weather Fights and Works for Man," by F. Barrows Colton, NATIONAL GEOGRAPIIIC MAGAZINE, December, 1943. t See "Man's Farthest Aloft," by Capt. Albert W. Stevens, NATIONAL GEOGRAI'PIC MAGAZINE, January, 1936, and "Ballooning in the Stratosphere," by Au guste Piccard, March, 1933.