Evening Star Newspaper, January 25, 1931, Page 84

i . THE SUNDAY STAR, WASHINGTON, D. €, JANUARY 25, YOST. ECHO CONQUERS FOG FOR FLYERS Slowly Winning the Battle Against viation’s Greatest Hazard, Science Now Goes One Step * Further in Giving Pilot Eyes to Pierce Dangerous Mists. BY JOHN L. COONTZ. SOUND WAVE shot down to the earth and its echo reflected back to H B g hpiE gk si Ef o At and puil g i RE : “Immzoocmtotsphmopented > by Lieut. Hegenberger and equipped with & sonic altimeter. In the rear cockpit was & pair ol stethoscopes, to all appearances the same as those used by a medical doctor. They were plugged in on the line. off Lieut. Hegenberger got the apparatus to . ieut. Hegenberger banked around the north angle of Bolling Field, headed his plane for the field and handed the controls over to me. Paying attention only to the altitude and to the longitudinal motion of the plane, I de- creased my speed by pulling back the throttle and gliding at about 75 miles per hour for the field with my head ducked down inside the cowling, relying only on the sonic altimeter to indicate to me the distance I was from the ground. Lieut. Hegenberger corrected any ten- dency on my part to veer off to one side or the other of the course or to drop a wing of the plane, although this was hardly necessary 8s the plahe, a Douglas basic training plane, was very stable laterally and directionally. His main function was to see that I avoided any obstruction, such as towers at the Navy Yard and other airplanes which might be flying in the vicinity. “Below 50 feet one does not rely on the gauge to indicate altitude, but on his aural or ear senses alone. At 50 feet the echo comes back a —‘nth of a second later; at five feet it comes g Remarkable photograph of a plane breaking through a fog. In the insert the pilot is shown with stethoscope adjusted fori receiving echoes shot up to him from the earth through use of the sonic altimeter. as most of the modern airplanes are equipped with very. efficient shock- gear, “pancaking” from such a height would not be excessive, consider: the circumstances surrounding the making of a blind landing in a fog. “With a perfect airport, one of good size, I believe it possible for a pilot to come in and compass. Perhaps the first instrument that early fiyers thought of was the compass—the hand to guide them home or show them the way across the continent through the air, erringly as the bird. Early fiyers flew by compass. For that matter, flyers still fily by the com pass, but the compass is not alone in them to their destination 3 destination is not only a given city, tain small tract of ground within that city on its rim. The pilot must not “port,” but he must come down, come safel to rest with his load whether it be human commercial freight. He must make it in rain, in fog, in snow, in sleet, from clouds by day and night the year around. LA} It tells a flyer his from the earth at amny given time. The field can be wrapped knows whether he is 50 or the ground. But how get d The pilot, when he before him in flight, when visibility has been shut off to come down or depend upon some instrumen on his instrumeént board to keep the of his plane normal. This problem has been solved for him by the artificial horizon. It nothing more than the horizon of the earth transferred to the dash of the plane. o Tflnmh-im‘i.—ndmfix- the instrument board and weighing only five pounds. The face of the mstrument sists of a smooth background, biue on the half to represent the sky, shading o a gray on the lower half to represent el i the bar remains horizontal, whereas and the airplane silhouette tilt The horizon bar is thus free to tilt, and can assume any of these positions. The instrument will cate banks up to 80 degrees and climbs or glides up to 45 degrees. The bar is held in the horizontal position by a small airspun gyro- scope mounted in a gimbal ring and having its spinning axis vertical.” Fe ¥e ! 5k 2 cast from towers at intervals of about 200 miles. A pilot on a course plugs in his set of earphones on his receiving instrument. He gets a dot and a dash if he is one side of his course, a dash and dot signal if he is the othe: side. If he is truly on his course he gets long dash—the blend of the det and dash. This is the aural or ear type of radio tion finder. It new has been supplemen the visual type. This consists of two vib: larger much than an ordinary cigarette pack- age. The box, when in use, is plugged into the dash of a plane’s receiving set. The position of a pilot in flying is indicated with respect to when to the left the white marking caused by the left reed becomes longer than the When the pilet is on the true course the reeds vibrate equally. As the fiyer beacon whose beam is being recorded reed instrument it becomes mecessary for him to cut down the volume of his receiving At the exact moment that he is over tion housing the beacon the reeds ing. They start again, this time im opposit: Continued on Twenticth Page