144 LAWRENCE HARGRAVE. 
ON THE CELLULAR KITE. 
By Lawrence Hargrave. 
[With Plate VII.] 
[Read before the Royal Society of N. S. Wales, August 5, 1896.] 
As there is little doubt that the cellular is a permanent type of 
kite, a few remarks will be of interest ; especially as its action 
and construction as hitherto explained are somewhat obscure. 
The first question that suggests itself, is, why should the cellular 
lift more per square foot than the ordinary single surfaced kite ! 
In a kite or flying machine the distribution of the lifting surface 
is most important. The value of the lifting surface depends 
within certain limits on the linear dimension that first meets the 
wind. Thus, a common kite of twenty-five square feet area can- 
_ not show more than about seven feet of edge to the wind, whereas 
a cellular one of twenty-five square feet area can easily show 
twenty feet of edge to the wind. 
The great stability of the cellular kite is due to the vertical 
surfaces. To understand this, it is necessary to grasp the truth, 
that a perfectly flat kite has no stability; and even with tail and 
side ropes is an inferior flyer. The more the kite bends back from 
the longitudinal centre line or back bone, the more stable it 
becomes. The angle between the two sides is called by flying- 
machine men the diedral angle, and without this or its equivalent, 
no flying apparatus will balance with any degree of certainty. 
x 
| 
1 
a a ae 
Let A BC be the diedral angle of a kite. B being the end 
view of the back bone. Resolve A B and B C into their com- 
ponents, and D B E is the breadth of surface that tends to lift 
