Tuesday, July 2, 2013

Prof Samuel P Langley's Flying Machine -- July 2, 2013

Samuel Pierpont Langley was a scientist and pioneer student of aviation. His Aerodrome Number 5, an unmanned steam-powered triplane, flew almost 3/4 of a mile on 06-May-1896. He never built a successful man-carrying ship.

From the 24-May-1896 Saint Paul Globe

Prof. Samuel A Langley's flying machine is very accurately pictured in the above cut. At Occoquan, Va., near Washington, D. C, the Smithsonian Institute professor recently tested this machine to his complete satisfaction. The machine rose 200 feet in the air and flew steadily for half a mile. Fuel in the engine then gave out and the machine sunk gently to the ground.

The flying machine carries a small steam engine of one-horse power. The whole contrivance weighs twenty-five pounds. Its light steel framework holds extended horizontally three sheets of thin canvas, one above the other. The length over all is fifteen feet.The engine runs two propellers.

The machine could fly 100 miles or even a much greater distance with a sufficient supply of steam. But the small engine employed is not of the condensing pattern, and has no means of using the same water over
and over. Prof. Langley will soon construct a flyer of large size, which will carry a proper mechanical equipment and be capable of extended flight. The one described is only a model for experimental purposes. The inventor has not troubled himself to any extent about the question of a suitable engine, which could be furnished easily enough when needed. The problem was to make a machine that would fly and fly in the right way, this accomplished, there was no difficulty in supplying the power required for a long trip.  In fact, the difficulties are greatly lessened by the enlargement of the machine. A flyer of this type eighty feet long would have a sufficient area of planes to sustain a powerful steam engine and a car carrying a number of passengers. The steam may be obtained from liquid fuel or by burning gas that has been compressed and loaded into cylindrical reservoirs of thin-drawn steel tubing. Such reservoir can be made to hold 100 times its
cubical contents of gas, and thus the airship is able to take on board a great quantity of fuel in a very small compass. The four-horse power Copeland engine now in the market weighs only twenty-seven pounds and occupies a floor space only ten inches square, its height being twenty-one inches.

Prof. Langley calls his machine an "aerodrome" or air-runner. It travels at the rate of eighteen miles an hour. The Inventor regards it as an important point of vantage that it is able to go so slowly. This will be understood when it is explained that the sustaining power required by the airship becomes less in proportion to the increase of its speed. A man can skate over thin ice which would not bear him if he stood still.  The faster he goes the thinner the ice needed to hold him up. If he goes fast enough he could run over the surface of a pond of water. The same principle applies to the aerodrome in its progress through the atmosphere.

If the aerodrome is able to sustain itself when flying only eighteen miles an hour, it can carry twice as muoh weight when going twice as fast Until recently it has been imagined that the atmosphere was not dense enough for propellers to act upon it effectively. This belief is now exploded. Prof. Langley's experiments have proved that it is only necessary to make the propellers revolve fast enough in order to force the airship along at a rate almost infinitely fast.  Also he has discovered that the resistance offered by the air to the aerodrome is only one-fiftieth part of what was supposed, implying that so much lost motive power is needed. The speed attained by the airship of this pattern will be 100 miles an hour or more if desired.

The theory of the aerodrome is wholly different from that of the balloon. Unlike the latter. It does not aim to float by reason of being lighter than the air; Prof. Langley's machine weighs about 1,000 times as much as the air which supports it. It relies upon the air currents, as does a soaring bird. In fact, its principle is derived from the suggestions offered by birds of the vulture type.  There is no better example of soaring than in the flight of a vulture, which, though large and heavy, will remain a whole day in the air without a single wing-beat, simply opposing its wings to the air currents and thus obtaining support from them. The start with the machine must be made from a height. Not the best flyer among tho soaring birds can make a start from the ground without much difficulty. The eagle takes a long run before It can rise, thus gathering momentum. The sky-searching condor of the Andes gets a start usually by dropping from a lofty crag.

An important part of the problem of human flight is the question of landing safely.  Prof. Langley believes that he sees the way out of this trouble, but he guards his ideas on the subject very carefully.

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