Page:Popular Science Monthly Volume 91.djvu/877

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Popular Science Monthly


���How Airplane Engines Are Tested at the Factory

PROBABLY nothing that is made in our factories to-day is tested more carefully than an airplane. An air- plane has not the solidity of an automobile or of a power boat. It is very light and elastic. Yet it calls for a high power engine. To put a hundred horsepower engine in an airplane without first test- ing it would be to invite disaster. An engine that gives an ideal perform- ance when on a bedplate securely bolted to the fac- tory floor might be trusted in the solid chassis of an automobile or the sub- stantial hull of a launch but never in the flimsy, vibrating fuselage of an airplane.

Where airplane motors are made in large numbers it is not practicable to test them in actual fuselages because the fuselages would deteriorate too rapidly. Therefore a good imitation fuselage has been designer! to meet the needs of the engine makers. This is made of angle iron and rests on real airplane wheels. The motor is controlled from a regular pilot's seat. The water jackets are connected with water, mains by flexible hose resting on a separate wooden frame.

It is not at all difficult to test an air- plane motor because the propeller is its flywheel and it is only necessary to as- certain whether or not it keeps up a standard amount of pull and works steadily. This is measured by a sim- ple spring balance. The engine must be tested also, to de- termine how it is af- fected by inclining it up or down as it

��must be inclined when flying. This test is accomplished by hooking the spring balance lower or higher to a massive post behind the testing fuselage. While the pilot controls the motor a mechanician stands by to watch the per- formance of the engine. A safety attachment holds the fuselage in place in case the spring should break.

In this way it is possible to test the airplane en- gine very thor- oughly before it is put into service in the air, without endanger- i n g the lives of the work-

��Testing an airplane engine by means of an imitation station- ary fuselage made of angle iron mounted on airplane wheels

���This wooden-soled, zinc protected garden- ing shoe may serve our trench-fighters

��Protecting Your Shoes from Mud — in War Gardens or Trenches

THE patriotic citizens who planted and tended war gardens in response to the urgent advice of the Government dur- ing the past year, found that weeding is best accomplished after a rain, when the ground is soft and yielding. The house- wives had to learn something too in the line of patience, which was needed when so much cleaning up had to be done on account of the gardeners coming indoors with their muddy feet.

I. E. Harris, an employee in the Census Office, in Washington, D. C., found a way to protect his shoes from the mud so that when he came in out of the garden there would be no tracks for the housewife to complain about. He designed a garden shoe with canvas upper and wooden sole and around the sole he shaped a piece of zinc, tacking it to the sole. He has offered his idea to the Government.

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