SAMUEL PIERPONT LANGLEY (/ˈlæŋli/ ; August 22, 1834 – February 27, 1906) was an American astronomer , physicist , inventor of the bolometer and pioneer of aviation .
* 8 References
* 8.1 Notes * 8.2 Bibliography
* 9 External links
He was born in Roxbury, Boston on 22 August 1834.
Boston Latin School
Langley arrived in
As railroads became operational, that unpredictability of time became dangerous. Trains ran by a published schedule, but the scheduling was chaotic. If the watches of an engineer and a switch operator differed by even a minute or two, it could mean disaster. Two trains could be on the same track at the same time and crash.
Using astronomical observations obtained from the new telescope, Langley devised a precise time standard – including time zones – that became known as the Allegheny Time System . Initially he broadcast time signals to Allegheny city business and the Pennsylvania Railroad . Eventually, twice a day, the Allegheny time signals broadcast the correct time via 4713 miles of telegraph lines to all railroads in the US and Canada. Langley used the money from the railroads to finance the observatory. From about 1868, revenues from the Allegheny Time continued to fund the observatory until the US Naval Observatory provided the signals for free in 1883.
Once funding was secure, Langley devoted his time at the Observatory initially in researching the sun. He used his draftsman skills (from his first job right out of high school) to produce hundreds of drawings of solar phenomena, many of which were the first the world had seen. His 1873 remarkably detailed illustration of a sun spot, observed while using the observatory's 13-inch Fitz-Clark refractor became a classic. It is featured on page 21 of his book, The New Astronomy, but was also widely reprinted – in the Americas as well as throughout Europe.
In 1886, Langley received the inaugural
Henry Draper Medal
Langley's steam-powered Aërodrome No. 5 in flight, May 6, 1896.
Alexander Graham Bell
Langley attempted to make a working piloted heavier-than-air aircraft . His models flew, but his two attempts at piloted flight were not successful. Langley began experimenting with rubber-band powered models and gliders in 1887. (According to one book, he was not able to reproduce Alphonse Pénaud 's time aloft with rubber power but persisted anyway.) He built a rotating arm (functioning like a wind tunnel ) and made larger flying models powered by miniature steam engines . Langley realised that sustained powered flight was possible when he found that a 1 lb. brass plate suspended from the rotating arm by a spring, could be kept aloft by a spring tension of less than 1 oz.
He met the writer
Through Roosevelt I met Professor Langley of the Smithsonian, an old man who had designed a model aeroplane driven—for petrol had not yet arrived—by a miniature flash-boiler engine, a marvel of delicate craftsmanship. It flew on trial over two hundred yards, and drowned itself in the waters of the Potomac, which was cause of great mirth and humour to the Press of his country. Langley took it coolly enough and said to me that, though he would never live till then, I should see the aeroplane established.
His first success came on May 6, 1896 when his Number 5 unpiloted model flew nearly 3/4 of a mile after a catapult launch from a boat on the Potomac River. The distance was ten times longer than any previous experiment with a heavier-than-air flying machine, demonstrating that stability and sufficient lift could be achieved in such craft.
On November 11 that year his Number 6 model flew more than 5,000 feet (1,500 m). In 1898, based on the success of his models, Langley received a War Department grant of $50,000 and $20,000 from the Smithsonian to develop a piloted airplane, which he called an "Aerodrome " (coined from Greek words roughly translated as "air runner"). Langley hired Charles M. Manly (1876–1927) as engineer and test pilot . When Langley received word from his friend Octave Chanute of the Wright brothers ' success with their 1902 glider, he attempted to meet the Wrights, but they politely evaded his request.
While the full-scale Aerodrome was being designed and built, the internal combustion engine was contracted out to manufacturer Stephen M. Balzer (1864–1940). When he failed to produce an engine to the power and weight specifications, Manly finished the design. This engine had far more power than did the engine for the Wright brothers' first airplane—50 hp compared to 12 hp. The engine, mostly the technical work of men other than Langley, was probably the project's main contribution to aviation. The piloted machine had wire-braced tandem wings (one behind the other). It had a Pénaud tail for pitch and yaw control but no roll control, depending instead on the dihedral angle of the wings, as did the models, for maintaining roughly level flight.
In contrast to the Wright brothers' design of a controllable airplane
that could fly against a strong wind and land on solid ground, Langley
sought safety by practicing in calm air over the
In the first attempt, Langley said the wing clipped part of the catapult, leading to a plunge into the river "like a handful of mortar," according to one reporter. On the second attempt the craft broke up as it left the catapult (Hallion, 2003; Nalty, 2003). Manly was recovered unhurt from the river both times. Newspapers made great sport of the failures, and some members of Congress strongly criticized the project.
The Aerodrome was modified and flown a few hundred feet by Glenn Curtiss in 1914, as part of his attempt to fight the Wright brothers' patent, and as an effort by the Smithsonian to rescue Langley's aeronautical reputation. Nevertheless, courts upheld the patent. However, the Curtiss flights emboldened the Smithsonian to display the Aerodrome in its museum as "the first man-carrying aeroplane in the history of the world capable of sustained free flight". Fred Howard, extensively documenting the controversy, wrote: "It was a lie pure and simple, but it bore the imprimatur of the venerable Smithsonian and over the years would find its way into magazines, history books, and encyclopedias, much to the annoyance of those familiar with the facts." (Howard, 1987). The Smithsonian's action triggered a decades-long feud with the surviving Wright brother, Orville.
Langley had no effective way of addressing the Wright brothers' central innovation of controlling an airplane too big to be maneuvered by the weight of the pilot's body. So if the Aerodrome had flown stably, as the models did, Manly would have been in considerable danger when the machine descended, uncontrolled, for a landing—especially if it had wandered away from the river and over solid ground.
Air and sea craft, facilities, a unit of solar radiation, and an
award have been named in Langley's honor, including: First
failure of the manned Aerodrome,
Langley Gold Medal by the
In 1878 Langley invented the bolometer , an instrument initially used
for measuring far infrared radiation. The bolometer has enabled
scientists to detect a change of temperature of less than 1/100,000 of
a degree Celsius. It laid the foundation for the measurements of the
amount of solar energy on the Earth. His 1881 paper, The
Radiant Energy, became a scientific classic. He made one of the first
attempts to measure the surface temperature of the Moon, and his
measurement of interference of the infrared radiation by carbon
dioxide in Earth's atmosphere was used by
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Starting with his tenure at
* ^ "Tableaux des prix décernés". Comptes rendus hebdomadaires
des séances de l\'Académie des sciences. 117. 1894. p. 1006. (The
French Academy awarded the 1893 prizes on 18 December 1893.)
* ^ "Science Prizes". American Naturalist. 28. U. of Chicago Press.
1894. p. 290.
* ^ BIOGRAPHICAL INDEX OF FORMER FELLOWS OF THE ROYAL SOCIETY OF
EDINBURGH 1783 – 2002 (PDF). The Royal Society of Edinburgh. July
2006. ISBN 0 902 198 84 X .
American Antiquarian Society Members Directory
University of Pittsburgh
* A Dream of Wings: Americans and the Airplane, 1875-1905, by Dr. Tom D. Crouch, W. W. Norton, 1981 * Taking Flight: Inventing the Aerial Age, from Antiquity through the First World War, by Dr. Richard P. Hallion, Oxford University Press, 2003 * Wilbur and Orville: A Biography of the Wright Brothers, by Fred Howard, Dover, 1987 * A Heritage of Wings, An Illustrated History of Naval Aviation, by Richard C. Knott, Naval Institute Press, Annapolis, Maryland, 1997 * Winged Shield, Winged Sword: 1907-1950: A History of the United States Air Force, by Bernard C. Nalty, University Press of the Pacific, 2003 * Aviation, The Pioneer Years, edited by Ben Mackworth-Praed, Studio Editions, Ltd., London, 1990 * To Conquer The Air—The Wright Brothers and the Great Race for Flight, by James Tobin, Free Press, division of Simon Gennaio 1996. * Selling the True Time: nineteenth-century timekeeping in America, by Ian R. Bartky, Stanford University Press, 2000
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