Samuel Pierpont Langley

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Samuel Pierpont Langley (August 22, 1834, Roxbury, Massachusetts (near Boston) – February 27, 1906, Aiken, South Carolina) was an American astronomer, physicist, inventor of the bolometer and pioneer of aviation. He graduated from Boston Latin School, was an assistant in the Harvard College Observatory, then became chair of mathematics at the United States Naval Academy. In 1867, he became the director of the Allegheny Observatory and a professor of astronomy at the Western University of Pennsylvania at Pittsburgh a post he kept until 1891 even while he became the third Secretary of the Smithsonian Institution in 1887. Langley was the founder of the Smithsonian Astrophysical Observatory.

In 1886, Langley received the Henry Draper Medal from the National Academy of Sciences for his contributions to solar physics. His publication in 1890 of infrared observations at the Allegheny Observatory in Pittsburgh together with Frank Washington Very was used by Svante Arrhenius to make the first calculations on the greenhouse effect.

[edit] Aviation work

Langley attempted to make the first working piloted heavier-than-air aircraft. His models flew but his two attempts at piloted flight, though less ambitious than the Wright brothers' flights, were not successful.

Langley began experimenting with rubber powered models and gliders. (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 (with function similar to the Wright brothers' wind tunnel) for testing. He obtained a War Department grant of $50,000 and $20,000 from the Smithsonian Institution to develop a piloted airplane and proceeded to larger models with steam and gasoline power. These flew free for considerable distances, demonstrating stability and sufficient lift. They had elaborate wire braced structures. He hired a successful glider pilot to work with him, offered financial support to the Wright brothers (not accepted), and hired Charles M. Manly as engineer and test pilot.

While the full-scale vehicle was being designed and built, the internal combustion engine development was contracted out to an engine manufacturer. When the contractor failed to produce an engine to the power and weight specifications, Manly finished the design. This engine had far more power per weight than did the Wright brothers' engine that powered the first airplane. The engine, though mostly not the direct technical work of Langley, was probably the project's main contribution to aviation. [1]

His piloted machine had wire-braced tandem wings (one behind the other). It had pitch and yaw control but no roll control, depending instead on stability, like the models, for maintaining its roll angle. In contrast to the Wright brothers' approach of designing a light and agile airplane that could be flown against a strong wind, Langley avoided fatal accidents by practicing over water, the Potomac River. This required a catapult for launching. The craft had no landing gear, the plan being to crash into the water after demonstrating flight. They gave up the project after two crashes on take-off on October 7 and December 8, 1903. Manly was recovered unhurt from the river.

Langley's aircraft was modified and flown by Glenn Curtiss, in 1914, as part of his attempt to fight the Wright brothers' patent, but the court upheld the patent.

Langley appears to have 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 "Airdrome" had taken off and flown stably, as the models did, Manly would have been in considerable danger and the Wright Brothers' credit would be little reduced. To his credit, Langley had to write reports and proposals during this project, while the Wright brothers were spending their own money.

A number of things related to aviation have been named in Langley's honor, including:

• Langley medal
• NASA Langley X-43A Hyper-X
• NASA Langley Research Center (NASA LaRC), Hampton, Virginia
• Langley Air Force Base
• Langley Memorial Aeronautical Laboratory
• Langley unit of solar radiation
• USS Langley (CV-1)
• USS Langley (CVL-27)

In World War II the United States liberty ship SS Samuel P. Langley was named in his honor.

[edit] References

• A Heritage of Wings, An Illustrated History of Naval Aviation, by Richard C. Knott, Naval Institute Press, Annapolis, Maryland, 1997
• Aviation, The Pioneer Years, edited by Ben Mackworth-Praed, Studio Editions, Ltd., London, 1990

[edit] External links

• http://www.flyingmachines.org/lang.html
• http://www.centennialofflight.gov/index2.cfm

Preceded by: Spencer Fullerton Baird

Secretary of the Smithsonian Institution 1887-1906

Succeeded by: Charles Doolittle Walcott

Persondata
NAME	Langley, Samuel Pierpont
ALTERNATIVE NAMES
SHORT DESCRIPTION	American physicist and pioneer of aviation
DATE OF BIRTH	August 22, 1834
PLACE OF BIRTH	Roxbury, Massachusetts
DATE OF DEATH	February 27, 1906
PLACE OF DEATH	Aiken, South Carolina