Show Keeping Up 0 c n c ere e I I o 0 Science Service Service Miniature Airplanes Now Nov ow Fly Freely in New Nev Test Tunnel Scientists Test Catapult for Launching Transports By WATSON ATSON v DAVIS Director Science Service Langley Field Va Minia Minia Miniature ture airplanes take off and maneuver maneuver maneuver ma ma- for the sake of science nce in the worlds world's first free flight wind tunnel just demonstrated for the first time by the N National National Na Na- a- a Advisory Committee for Aeronautics at its laboratories here Instead of the small counterpart of a sized full-sized airplane being held conventionally in an experimental blast of air the artificial breeze is increased until the model takes of off by itself and flies freely Then ailerons ailerons ailerons ailer ailer- ons and rudder are controlled by magnetic fields acting on small smaIl electromagnets elec tro-magnets tro in the models model's wings The scientist in charge maneuvers the test model plane just as a pilot handles a real one We expect that this new method of studying airplane stability and control will give us much information information information tion directly that we have hitherto obtained theoretically or by empirical empirical empirical em em- estimation said Dr George W. W Lewis N N. A. A C. C A A. A director of research i Bumps or gusts of wind are I measured and studied by two new devices devised by N. N A. A C C. C A A. A ex ex- ex- ex i Instrument Fits Pocket I I One of these is a bump recorder small smaIl enough to fit into the pocket About of these instruments are placed in airplanes and seaplanes of different types during actual flight One of them has been carried by bythe bythe the China Clipper on round trips between San Francisco and Manila From the curve traced by the instrument instrument instrument in in- strument engineers are able to reconstruct reconstruct reconstruct re re- re- re construct every roughness of the voyage and tell what what stresses stresses the craft withstood I Gusts are made to order in a new tunnel and model airplanes are catapulted catapulted catapulted cat cat- into them As fast as an arrow is ic IQ shot from a n 1 bow the iha th tin tin u u. u UJ Y plane is accelerated to 50 miles per hour in a few feet of travel Hit by bythe bythe the gust its action is recorded by a motion picture camera Reduces Take-Off Take Distance Just by reducing the size of rivets in an airplane wing by one thirty- thirty second of an inch it is possible to reduce the power necessary by horsepower This is one result of the experiments on the friction drag on the wings of large modern I airplanes In operating high performance performance performance per per- modern aircraft the import importance importance im im- port nce of smooth surface in a awing awing awing wing is so great that the N. N A. A C. C A. A e experts suggest it may be found economical to have service crews wipe of off accumulated dirt and dust duston on wing surfaces at every stop Large air transports leaving our airports in the future may be catapulted catapulted catapulted cata cata- in order to assist their takeoff takeoff takeoff take take- off and reduce the long run now necessary if a suggestion of the N. N A. A C. C A. A is adopted A catapult with half the acceleration of gravity would reduce the take-off take distance from 1000 feet to 1150 feet |