Parachute Safety Device for Airplanes 



A new attempt to revive the late Sir 

 Hiram Maxim's idea of twenty years ago 



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OF his first machine Sir Hiram 

 Maxim said, over twenty years 

 ago, that, completely stalled in the 

 air, it would "pancake" down with the 

 velocity of a fall of four feet. But these 

 old machines were loaded barely more 

 than one pound to 

 the square foot, and 

 their center of grav- 

 ity was far below 

 their carrying sur- 

 face. The arrange- 

 ment, as we know 

 now, prevented easy 

 flight, but it made 

 them good para- 

 chutes. The more 

 perfect and efficient 

 the modern airplane 

 became, the more it 

 lost its former like- 

 ness to a parachute. 



The wings of mod- 

 ern airplanes bear 

 a load of five to 

 seven pounds to the 

 square foot and the 

 center of gravity has been raised. Stalling 

 and pancaking are nowadays considered 

 worse than upsetting and "looping the 

 loop"; yet pancaking, that is, descending 

 like a parachute, is ob nously the safest 

 way to land on badly brol'en, mountain- 

 ous ground. 



Very interesting is a revival of Maxim's 

 parachute idea in modified form, by 

 Gerrit Van Daam, because it aims at 

 making safe not only stalling but also 

 landing on the worst ground. It is not 

 feasible v/ith heavily loaded biplanes, 

 since in their case one wing surface blan- 

 kets the other; but with lightly loaded 

 monoplanes of the Bleriot type the plan 

 may work out satisfactorily. What such 

 monoplanes lack in surface for a para- 

 chute-like descent, the inventor makes 

 up, more or less, by turning the wings 

 into true, highly-arched parachutes of 

 increased air-resistance. 



A parachute is tightly folded ovf the 

 whole upper surface of each wing, being 



By releasing the parachute and opening 

 long slots in the wings through which 

 the air rushes under the parachute, the 

 descent of the airplane is made safe 



held in place by a netting. When 

 needed, this netting is instantly loosened, 

 and at the same time a long slot opens 

 along the center line of each wing, ad- 

 mitting the air from below into the 

 spacious pocket formed by the distending 

 parachute, now held only by the margin 

 of the wing. 



Smoothness of the wing tops in flight is 

 absolutely essential; 

 so the folded para- 

 chute and the net- 

 ting will have to be 

 covered, while not 

 in use, by a smooth 

 light shell firmly se- 

 cured to resist the 

 air suction, yet easily 

 removed when nec- 

 essary. Of greater 

 importance is a de- 

 vice that will keep the 

 pancaking airplane 

 on an even keel dur- 

 ing descent. That 

 is not so easy with a 

 machine of the Ble- 

 riot type. In that machine, the tail 

 makes an excess of surface toward the 

 rear, while the advanced center of 

 gravity, balancing the equally advanced 

 center of lift, gives an excess of weight 

 in front. The only remedy would seem 

 to be control independent of the 

 machine's headway, or adjustable rudders 

 with a circular motion of their own, which 

 remain efficient in a stalled machine. 



Numerous attempts have been made 

 in the past by inventors in many countries 

 to utilize the principle of the parachute 

 in safety devices, but the success has not 

 been encouraging. Parachutes have been 

 found useful and fairly reliable for drop- 

 ping from observation balloons, but have 

 failed to give satisfaction as a safe means 

 of escape in practically all other cases. 

 They have not been used extensively- for 

 military purposes; but perhaps this new 

 device may solve a hitherto battling 

 problem and thus add to the balance 

 of safety in the aviator's favor. 



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