July 25th, 1909, the Frenchman was carried in a
monoplane 24 1/2 feet in spread, and with a total sustaining
surface of 150 1/2 square feet. The total weight of
the outfit, including machine, operator and fuel sufficient
for a three-hour run, was only 660 pounds. With
an engine of (nominally) 25 horsepower the distance of
21 miles was covered in 37 minutes.

Which is the Best?

Right here an established mathematical quantity is
involved. A small plane surface offers less resistance
to the air than a large one and consequently can attain
a higher rate of speed. As explained further on in this
chapter speed is an important factor in the matter of
weight-sustaining capacity. A machine that travels one-
third faster than another can get along with one-half the
surface area of the latter without affecting the load. See
the closing paragraph of this chapter on this point. In
theory the construction is also the simplest, but this is
not always found to be so in practice. The designing
and carrying into execution of plans for an extensive
area like that of a monoplane involves great skill and
cleverness in getting a framework that will be strong
enough to furnish the requisite support without an undue excess
of weight. This proposition is greatly simplified
in the biplane and, while the speed attained by the latter
may not be quite so great as that of the monoplane, it
has much larger weight-carrying capacity.