Popular Science Monthly 



861 



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. 



