20 



The National Geographic Magazine 



Method of Flying the Oionos Kite 



Pieces of red silk are attached to several meters of the 

 flying cord with the object of rendering the direction 

 of the cord visible on the photograph plate 



Oionos Kite with Movable Tail Controlled by Swingin 

 Head-load of Lead 



When released in the air at a considerable elevation it acts very much 

 like a soaring bird, moving forward against the wind or swinging 

 around in large circles. It is then, in effect, a free gliding machine, 

 which acquires considerable velocity in the horizontal direction, 

 while descending gently in the vertical direction. The head-load 

 gives the machine a slight tendency to dive, which is resisted by 

 the steering action of the tail when headway is gained. The moment 

 the head is depressed, as in diving, the weight swings forward, thus 

 automatically causing the elevation of the tail 



what would it profit a man were 

 he to gain the whole world and 

 lose his own equilibrium in the 

 air ? A kite composed exclusively 

 of multitudinous winged cells 

 seems to possess this property of 

 automatic stability in a very 

 marked degree. If, then, its Hft- 

 ing power is sufficient for our 

 purpose, there is no necessity for 

 the introduction of a factor of 

 danger by the addition of hori- 

 zontal surfaces. Of course, the 

 addition of such surfaces would 

 enable us to secure the desired 

 lifting power with a smaller, and 

 therefore lighter, structure, and 

 this would be of advantage if we 

 could be sure of its stability in 

 the air. 



In employing tetrahedral 

 winged cells alone upon the hol- 

 low plan of construction in which 

 large empty spaces 

 occurred within the 

 kite, a practical diffi- 

 culty was encountered 

 arising from the enor- 

 mous size of the struc- 

 ture required for the 

 support of a man, 

 combined with the in- 

 creasing weakness of 

 the structure as it in- 

 creased in size. The 

 discovery that the 

 cells may be closely 

 massed together with- 

 out marked injurious 

 effects has completely 

 remedied this diffi- 

 culty; for upon this 

 plan not only is the 

 structural strength 

 improved by an in- 

 crease of size, but the 

 lifting power increases 

 with the cube of the 

 dimensions ; so that a 

 very slight increase in 

 the dimensions of a 



