Gas Barrage Engineers' Two i ind Tunnels Used To Test Golf Clubs, Airplanes, Cars Editor's note: The material for this article was obtained from interviews with Prof. Edward A. Stalker, acting head of the aeronautical engineering department this summer, and, Prof. Milton J. Thompson of the same de- partment. By BETSEY ANDERSON If you're having trouble with the behavior of your golf clubs, keeping1 shingles on your roof, jumping out of airplanes, racing cars, windmills, yacht sails, smoke areas, streamlining trains, or building airplanes and glid- ers, the aeronautical engineering de- partment of the College of Engineer- ing can no doubt solve your problem with the aid of their two wind tun- nels located in the basement of the East Engineering Building. Not only that, but, in sharp con- trast to the warm atmospheric con- ditions outside, the two tunnels, one a 50-foot long, 8-foot high model and the other a smaller student model, provide breezes which can be turned on and off at will and can be regulat- ed at any speed desired between the range of 15 and 120 miles per hour. However, at high speeds the tempera- ture increases to a point about ten de- grees warmer than the ou~tside air. Breezes of all kinds are blown through the pipelike chambers by the engineers to test the practicability and usefulness of various miniature models made to scale. The tunnel is so perfectly constructed that, if the small model is made completely to scale, all the necessary points may be tested before the larger model is built, thus reducing the cost of experiment- ing on different shapes and varieties at actual size. Consequently, much more experimentation is made pos- sible. In testing a plane, for example, the student works out all the necessary computations and plans on paper, and then builds a miniature model to scale and places it on the three vertical wires that hold it up in the tunnel and tests its lifting power and re- sistance. The long rectangular tunnel con- sists of three tubular chambers through which the wind is blown. The model is placed in the middle sec- tion, hung from the ceiling by three vertical wires, two of them placed at the wings of the plane and one at the tail. Then the test is started and the fan starts to 'suck in the wind, caus- ing air currents to blow out in back of it in somewhat the same manner as if a household fan had been turned backward. Thus, by holding the model stationary and blowing air past it, the same effect %is gained as if the air were stationary and the plane were dlying through it. The air is sucked back into the two other chambers, one on either side of the fan and thus is continually circulating during tests. Honeycomb chambers in the two pipe-like outside chambers keep the wind straightened after rounding the corners and also keep the speed uniform. The walls in the two outside channels are plastered to make them more smooth so the air can go past them at a greater speed. As the test progresses, the charac- teristics of the model at different speeds and positions is worked out by those taking part in the experiment. At least two and usually four men are needed to take care of the data. The tunnel is one of the few of its size in operation in the country, the number probably not exceeding more than 30 at, the most, although there are quite a few smaller ones used mainly for demonstration rather than testing purposes. Most of them are maintained by universities and the model at Michigan possesses the repu- tation of being perhaps the most out- standing in the Middle West. It is a model of the double return type. A force of 50 policemen and deputy sheriffs, recruited from North Shore towns, used a barrage of tear gas to drive between 400 and 500 strike demonstrators from the plant of the Chicago Hardware Foundry Co. in North Chicago, Ill. The strikers are shown here in retreat, water-soaked handkerchiefs clasped to their faces. lIj F - ~------ --_-- :r. - e te Ve HUGE OUT-OF-DOOR CONCERT 215 MUSICIANS University Summer Session Band High School Clinic Band Conductors: / WILLIAM D. REVELLI,University of Michigan GERALD R. PRESCOTT, University of Minnesota -Hear Sousa's "Stars and Stripes Forever" played by this great musical aggregation. Friday,July F ERRY 29,,7 P. M. FIELD O.D.MORRILL 314 S. State St. Typewriters, Stationery, Studernt andiOffie SunnGies Saffel andBush No Admission Charge In Case of RAIN, the Program will be given in Hill Auditorum at 8:30 P.M. """ * "JP" """ i 1 V . 0 E M N T E! L L Sb A N Q T H E R " ikf Since 1908 Phone 6815 _____ _ l ._, FOR W MICI-IIGAN MEN' . 0 0 MAKE THE TAP ROOM YOUR EATING HEADQUARTERS )MF FOOD AMAR F FAR YnA IR DnT T.A R CFNTR ALLY LOCATED . +r/ HOT ESC N aIs ~U 11 I