s 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.

A Powerful Light Motor.

Another successful American aviation motor is the aeromotor,
manufactured by the Detroit Aeronautic Construction. Aeromotors are made
in four models as follows:

Model 1.--4-cylinder, 30-40 h. p., weight 200 pounds.

Model 2.--4-cylinder, (larger stroke and bore) 40-50 h. p., weight 225
pounds.

Model 3.--6-cylinder. 50-60 h. p., weight 210 pounds.

Model 4.--6-cylinder, 60-75 h. p., weight 275 pounds.

This motor is of the 4-cycle, vertical, water-cooled type. Roberts
Aviation Motor.

One of the successful aviation motors of American make, is that produced
by the Roberts Motor Co., of Sandusky, Ohio. It is designed by E. W.
Roberts, M. E., who was formerly chief assistant and d