The method of starting the Voisin airship is entirely different from the Wrights’. The machine is mounted on two wheels, attached to the girder body with an arrangement of springs to take up the shock on landing. To launch the aëroplane, the propellers are started, and the machine rushes forward on its wheels until it has developed sufficient speed to send it up. It may thus rise from an ordinarily level ground, and does not require the apparatus used by the Wrights. The pilot and passenger sit in much the same position as in the Wright aëroplane.
The Voisin model weighs 300 pounds more than the Wrights’ or 1590 pounds. It has a supporting surface of 535 square feet, and a speed, under favorable conditions, of 38 miles an hour. Another point of difference from the Wright model is the propeller, which is single and measures seven feet six inches in diameter. The motor, an eight cylinder Antoinette, usually gives fifty horse power at 1100 revolutions per minute. The Wright Brothers, by the way, make their own motors, which are considered inferior to the French motors.
The smallest and swiftest of all the aëroplanes is the Curtiss-Herring model, which was invented by two Americans whose names it bears. Its general form suggests the Wrights’ machine. The span of the large planes is only 29 feet or under, the depth but four feet six inches, and the spacing four feet six inches. It has a total wing surface of but 258 square feet. The weight, not including the pilot, is only about 450 pounds. When seen beside the aëroplane of ordinary size, the little craft looks like a very large toy model. It has the appearance of a smart little racer, however, and its maximum speed is over 50 miles an hour.
Everything has been sacrificed in the Curtiss-Herring model for the sake of compactness. The forward rudder, which seems small even for such a craft, consists of two planes, one above the other, whose combined area is only twenty-four square feet. Unlike the Wright or Voisin models, this forward rudder carries a vertical plane which makes for stability. There is no tail as in the Voisin model, and the rear, vertical rudder consists of a horizontal plane six feet wide and two feet, three inches deep and a vertical rudder below it, two feet deep and three feet four inches wide. The front and rear planes extend out from the main frame about the same distance. The main stability planes, curiously enough, are placed inside the frame. There are two of these, one at either end of the main plane.
An ingenious method has been followed to control the various planes. The pilot sits facing a wheel, like that of an automobile, which is so rigged that by simply pushing it from him or pulling it back, he may lift or decline the front planes. By turning this wheel he operates the rudder in the rear, exactly as you would steer an automobile or a boat. The balancing mechanism in turn is connected with a frame which fits about the pilot’s shoulders like a high-backed chair and is operated by merely leaning to one side or the other. This has the same effect as warping the main planes. The control of the machine becomes largely automatic. If the pilot feels that his aëroplane is tilting over at one end or the other, he merely leans to one side or the other, and, without taking his hands from the wheel before him, has the machine under perfect control. Even the motor is controlled by pedals placed under the pilot’s feet.
This little racer is mounted on three wheels, one well forward and two in the rear about half way between the main planes and the horizontal rudder. An original feature of this model is a foot brake which, connecting with the forward wheel, helps to slow down the machine on landing, just as you close the brake of an automobile. There is only one rudder measuring six feet in diameter, which is unusually large considering the size of the model. The engine is mounted at the center of the space between the two main planes, and the propeller, which is kept on a line with it, is therefore considerably higher than in most aëroplanes. The lower plane comes very near the ground. It is only raised by about the height of the bicycle wheels. It is thought by some that this arrangement of the engine blankets the propeller, while others argue that the suction produced in this way increases the thrust of the propeller. The machine is built of Oregon spruce, the wings are covered with oiled rubber silk, and the entire mechanism is beautifully finished in every detail.
PLATE XXV.
Another View of the Wright Model.
The ingenuity of the designers of aëroplanes is astonishing. With so many aëroplanes in the field, or rather in the sky, it is surprising that they are not more alike. The Farman biplane, for instance, follows the same general proportion as the Wright machine, but there the similarity ends. To secure equilibrium in this model, four small planes are used, hinged at the back of the two main planes, and these, it has been found, take the place of the flexing device used by the Wrights. The two swinging planes on the lower wing are controlled by wires, while the upper two swing free. A single lever controls the two lower planes and the horizontal rudder.