Page:Popular Science Monthly Volume 88.djvu/741

 Popuhir Science ^lonihly

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���By means of a trigger which ipoves but forty inches, an aeroplane can be catapulted into the

air with a velocity equivalent to a run of forty feet on the ground. This new invention

advances the u^e of aeroplanes at sea far beyond anything yet achieved

��Catapulting Seaplanes from Battleships

AFKW years ago, when the thought of usnig aeroplanes in connection with battleships occurred to naval officers, the problem of launching was sohed in a crude way by means of temporary inclined platforms built on the deck. Apart from the military objection to such a structure, the weather conditions had to be decidedly favorable in order to insure a successful start for a flight. At no time was it considered practicable to launch the flying machine while the ship was in motion. The machine ran down on the platform on the regulation wheels of a land machine; they were not real sea- planes.

It was apparent that the Inclro- acroplanc or seajilane would have to be carried temporarily upon a car or truck from which it could be detached at the right moment and allowed to rise of its own imjiulse by reason of the supporting pressure of the air due to the speed acquired in a short run. It was also clear that the car would have to be quickly accelerated to full speed within a run of something like forty feet. This rapidly gathered headway had to be insured without jerks or jars. To this end Captain Washington I. Chambers

��of our navy has de\ised a compressed-air catapult, the compressed air operating a piston which, in its turn, actuates a wire rope traveling o^'er pulleys. A movement of but forty inches on the part of the piston is multiplied so as to draw the car forward forty feet.

To-day, the catapult has been so far perfected by the Bureau of Construction and Repair of the Na\y Department that it has become a permanent feature aboard the a\"iation ship U. S. S. North Carolina. It is now possible to launch in flight the service seaplanes while the cruiser is steaming along at fair speed.

The seaplane's motor is set going be- fore the catapulting process is started. In fact, the pilot docs not gi\'e the signal for launching until his engine is working just right. The im]>ulse a.ir for working the piston is drawn right from the torpedo air-supply system, and the working prcs- vsure is something like three hundred pounds to the square inch. B\' means of a cleverly designed valve the air is. ad- mitted progressively to the cylinder, ami in this wa\- the desired maxinunn speed is reached from zero without shock.

In the future, our na\>-, when lumd'rcds of miles from shore, will be able to send its seaplanes skyward with measurable indifference to the weather.

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