The Strength of Human Wings 



One hundred and twenty-two people can 

 stand on the wings of a big biplane 



IF the men who lost their lives in the early 

 years of the flying machine's develop- 

 ment could come back to life and gaze 

 upon the picture which accompanies this 

 article, they would first gasp in astonish- 

 ment and then they would approve en- 

 thusiastically the construction which made 

 it possible for sixty people to crowd upon 

 one.Thalf.of-a huge biplane's wings without 

 breaking, them. For, let it never be for- 

 gotten/ that some of the early martyrs who 

 dropped to a terrible" x death from great 

 heights, went to their doom because the 

 builders.. of;, their machines had no concep- 

 tion of .the structural * strength required to 

 buffet turbulent winds at high speed. 

 . Study, the pictured well. Note that the 

 wing section. of a biplane here depicted is 

 supported from a. heavy wooden frame and 

 not . from the.' floor. The wirig section is 

 held" only, on one side and extends freely 

 from that side into the air. Judging from 

 their size, the wings are , those of any 



enormous flying yacht. Although the sup- 

 porting surfaces of this yacht could evi- 

 dently sustain the weight of some one 

 hundred and twenty-six passengers, they 

 have not, of course, that amount of lifting 

 power. The crew of the vessel probably 

 amounts to four. Hence, the weight for 

 one hundred and twenty-two people is 

 available for the boat body, rudders, 

 engines, propellers and supplies, something 

 like over eight and one-half tons. More- 

 over, the human freight here pictured 

 clearly does notoverstrain the wings. 



The picture is an object lesson in reserve 

 strength. The stoutest storm-sails of an 

 old-fashioned sailing ship were never sub- 

 jected to such strains as those which must 

 be endured by that fabric of linen, wires, 

 and lattice-work of which the wings of a 

 modern flying-machine are composed. A 

 sail needs strength to resist mere tearing 

 alone. A flying-machine's wings must in 

 addition be so rigid that they will keep its 

 shape in the worst hurricane. Only the 

 pilot of an airplane knows how his wings 

 are strained when he drops at a steep 

 angle from a height of five thousand 

 feet in a swift downward glide for 

 home. It must bend no more than 

 if it were made of cast iron. To 

 this stiffness the modern 

 airplane owes its superior 

 stability. 



Testing the wings of the great 

 biplane by crowding upon it 

 a maximum human load 



