Since the first edition of this book was printed, early in 1910,
there has been a remarkable advance in the construction of aeroplane
motors, which has resulted in a wonderful decrease in the amount of
surface area from that formerly required. Marked gain in lightness and
speed of the motor has enabled aviators to get along, in some instances,
with one-quarter of
the plane supporting area previously used. The first Wright biplane,
propelled by a motor of 25 h. p., productive of a fair average speed of
30 miles an hour, had a plane surface of 538 square feet. Now, by using
a specially designed motor of 65 h. p., capable of developing a speed of
from 70 to 80 miles an
hour, the Wrights are enabled to successfully navigate a machine the
plane area of which is about 130 square feet. This apparatus is intended
to carry only one person (the operator). At Belmont Park, N. Y., the
Wrights demonstrated that the small-surfaced biplane is much faster,
easier to manage in the hands of a skilled manipulator, and a better
altitude climber than the large and cumbersome machines with 538 square
feet of surface heretofore used by them.
In this may be found a practical illustration of the principle that
increased speed permits of a reduction in plane area in mathematical
ratio to the gain in speed. The faster any object can be made to move
through the air, the less will be the supporting surface required to
sustain a given weight. But, there is a limit beyond which the plane
surface cannot be reduced with safety. Regard must always be had to the
securing of an ample sustaining surface so that in case of motor
stoppage there will be sufficient buoyancy to enable the operator to
descend safely.
The baby Wright used at the Belmont Park (N. Y.) aviation meet
in the fall of 1910, had a plane length of 19 feet 6 inches, and an
extreme breadth of 21 feet 6 inches, with a total surface area of 146
square feet. It was equipped with a new Wright 8-cylinder motor of 60 h.
p., and two Wright propellers of 8 feet 6 inches diameter and 500 r. p.
m. It was easily the fastest machine at the meet. After the tests,
Wilbur Wright said:
"It is our intention to put together a machine with specially
designed propellers, specially designed gears and a motor which
will give us 65 horsepower at least. We will then be able, after some
experimental work we are doing now, to send forth a machine that will
make a new speed record."
In the new Wright machines the front elevating planes for
up-and-down control have been eliminated, and the movements of the
apparatus are now regulated solely by the rear, or "tail" control.
