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The Wright biplane is a structure composed of two main surfaces, each 40 feet long and 6 feet 6 inches wide, set one above the other, parallel, and 6 feet apart. The planes are held rigidly at this distance by struts of wood, and the whole structure is trussed with diagonal wire ties. It is claimed by the Wrights that these dimensions have been proven by their experiments to give the maximum lift with the minimum weight.

Diagram showing the construction of the Wright biplane. The lever R is connected by the bar A with the rudder gearing C, and is pivoted at the bottom on a rolling shaft B, through which the warping wires W¹, W² are operated. The semicircular planes F aid in stabilizing the elevator system.

The combination of planes is mounted on two rigid skids, or runners (similar to the runners of a sleigh), which are extended forward and upward to form a support for a pair of smaller planes in parallel, used as the elevator (for directing the course of the aeroplane upward or downward). It has been claimed by the Wrights that a rigid skid under-structure takes up the shock of landing, and checks the momentum at that moment, better than any other device. But it necessitated a separate starting apparatus, and while the starting impulse thus received enabled the Wrights to use an engine of less power (to keep the machine going when once started), and therefore of less dead weight, it proved a handicap to their machines in contests where they were met by competing machines which started directly with their own power. A later model of the Wright biplane is provided with a wheeled running gear, and an engine of sufficient power to raise it in the air after a short run on the wheels.

Two propellers are used, run by one motor. They are built of wood, are of the two-bladed type, and are of comparatively large diameter—8 feet. They revolve in opposite directions at a speed of 450 revolutions per minute, being geared down by chain drive from the engine speed of 1,500 revolutions per minute.

The large elevator planes in front have been a distinctive feature of the Wright machine. They have a combined area of 80 square feet, adding that much more lifting surface to the planes in ascending, for then the under side of their surfaces is exposed to the wind. If the same surfaces were in the rear of the main planes their top sides would have to be turned to the wind when ascending, and a depressing instead of a lifting effect would result.

To the rear of the main planes is a rudder composed of two parallel vertical surfaces for steering to right or left.

The feature essential to the Wright biplane, upon which the letters patent were granted, is the flexible construction of the tips of the main planes, in virtue of which they may be warped up or down to restore disturbed equilibrium, or when a turn is to be made. This warping of the planes changes the angle of incidence for the part of the plane which is bent. (The angle of incidence is that which the plane makes with the line in which it is moving. The bending downward of the rear edge would enlarge the angle of incidence, in that way increasing the compression of the air beneath, and lifting that end of the plane.) The wing-warping controls are actuated by the lever at the right hand of the pilot, which also turns the rudder at the rear—that which steers the machine to right or to left. The lever at the left hand of the pilot moves the elevating planes at the front of the machine.

Sketch showing relative positions of planes and of the operator in the Wright machine: A, A, the main planes; B, B, the elevator planes. The motor is placed beside the operator.

The motor has 4 cylinders, and develops 25 to 30 horse-power, giving the machine a speed of 39 miles per hour.

A newer model of the Wright machine is built without the large elevating planes in front, a single elevating plane being placed just back of the rear rudder. This arrangement cuts out the former lifting effect described above, and substitutes the depressing effect due to exposing the top of a surface to the wind.

Courtesy of N. Y. Times.

The new model Wright biplane—without forward elevator.

The smallest of the Wright machines, popularly called the “Baby Wright,” is built upon this plan, and has proven to be the fastest of all the Wright series.