28.7
Wright.... 2 538 41.0
30.7
Farman.... 2 430 32.9
39.6
Voisin.... 2 538 37.9
39.6

No. of Weight Without
Propeller
Make Cylinders Horse Power Operator
Diameter
Curtiss... 8 50 600 6.0
Wright.... 4 25 1,100 8.1
Farman.... 7 50 1,200 8.9
Voisin.... 8 50 1,200 6.6

In giving the depth dimensions the length over all--from the extreme
edge of the front auxiliary plane to the extreme tip of the rear is
stated. Thus while the dimensions of the main planes of the Wright
machine are 41 feet spread by 6 1/2 feet in depth, the depth over all is
30.7.

Figuring Out the Details.

With this data as a guide it should be comparatively easy to decide
upon the dimensions of the machine required. In arriving at the maximum
lifting capacity the weight of the operator must be added. Assuming this
to average 170 pounds the method of procedure would be as follows:

Add the weight of the operator to the weight of the complete machine.
The new Wright machine complete weighs 900 pounds. This, plus 170, the
weight of the operator, gives a total of 1,070 pounds. There are 538
square feet of supporting surface, or practically one square foot of
surface area to each two pounds of load.

There are some machines, notably the Bleriot, in which the supporting
power is much greater. In this latter instance we find a surface area of
150 1/2 square feet carrying a load of 680 plus 170, or an aggregate of
850 pounds. This is the equivalent of five pounds to the square foot.
This ratio is phenomenally large, and should not be taken as a guide by
amateurs.

The Matter of Passengers.

These deductions are based on each machine carrying one passenger, which
is admittedly the limit at present of the monoplanes like those operated
for record-making purposes by Santos-Dumont and Bleriot. The biplanes,
however, have a two-passenger capacity, and this adds materially to the
proportion of their weight-sustaining power as compared with the surface
area. In the following statement all the machines are figured on the
one-passenger basis. Curtiss and Wright have carried two passengers on
numerous occasions, and an extra 170 pounds should there