Langley was serving as director of the Allegheny Observatory in Pittsburgh when he attended the American Association of the Advancement of Science in 1886. It was during this conference that he became fascinated by a presentation on the flight of birds. Shortly thereafter, Langley received permission from the Observatory to build a whirling-arm, an early device similar to the wind tunnel and used to study aerodynamic properties. With the largest whirling-arm built to that time, Langley proceeded on a four-year research effort that resulted in the publishing of Experiments in Aerodynamics. In this book, Langley methodically explored the measurement of atmospheric properties as well as the aerodynamic force on flat plates. He also described the effect of aspect ratio on lift, propeller design, the movement in center of pressure as it relates to stabilty and control, and the power required for flight. This research convinced Langley that heavier-than-air flight using mechanical engines was not only practical but within the limits of technology available at the time.
By this point, Langley was now secretary of the Smithsonian Institution in Washington DC, where he began a new series of experiments with small powered models. These models allowed Langley to test nearly 100 different aircraft configurations, but he eventually gave up this effort after learning little from the frail, breakable models. He then pursued a new and more sophisticated approach using steam-powered sub-scale flying machines that he called "aerodromes" (from the Greek aerodromoi, or "air runner"). Seven different aerodrome designs, numbered 0 to 6, were constructed, and Aerodrome no. 5 proved to be the most successful. Weighing in at 26 lb, the design featured twin tandem wings with highly cambered airfoils and two propellers driven by a 1-hp steam engine.
Tests flights of his unmanned aircraft gave Langley an appreciation of the importance of structural strength-to-weight ratio, power-to-weight ratio, and methods of maintaining controllability and stabilty. After three years of testing, re-designs, adjustments, and trial-and-error, Langley finally achieved success on 6 May 1896. Following a failed launch of his seventh design, Aerodrome no. 5 flew about 3,300 ft over 90 seconds. This noteworthy event marked the first time in history that a heavier-than-air aircraft had successfully completed a sustained flight under its own power.
Langley then proceeded with the final and most ambitious phase of his experiments as he attempted to build a full-scale manned aerodrome. The manned aircraft was essentially a much larger version of his earlier aerodromes but now powered by a 52.4-hp gasoline engine. In order to become airborne, Langley constructed a large catapult system mounted to the roof of a houseboat that he sailed in the Chesapeake Bay near Washington DC. Langley's aircraft was ready for its first test flight in late 1903.
On the first attempt, the aircraft failed to become airborne and suffered minor damage due to the forces imparted on its structure by the launch catapult. Following repairs, a second test flight was attempted 8 December 1903. Langley was so sure of success that he invited several prestigious guests from Washington and local newspaper writers to witness the event. Unfortunately, the lauch proved disastrous when the rear wing of the aerodrome collapsed just moments after takeoff. The subsequent crash was widely publicized and proved to be an embarrassing failure that damaged Langley's reputation for the remainder of his life.
Further compounding Langley's humiliation was the success of the Wright brothers who succeeded where Langley had failed. Just days after the failure of the Langley Aerodrome, the Wright Flyer became the first successful manned powered aircraft on 17 December 1903.
Due to the criticism he received after the Aerodrome crash, Langley never again attempted another flight and remained rather bitter about the affair until his death in 1906. However, his full-scale aerodrome did get a second lease on life when his former employer, the Smithsonian Institute, sought to rehabilitate Langley's reputation. In 1914, the Smithsonian contracted aviation pioneer Glenn Curtiss to rebuild and fly the Aerodrome to prove that it was a flyable design. Following several months of restoration and repairs, Curtiss succeeded in flying the aerodrome on 28 May 1914.
The Smithsonian then made the dubious claim that Langley had been the first to successfully develop a manned powered aircraft after all, not mentioning the fact that Curtiss had found it necessary to make some 93 modifications to Langley's design to make it airworthy. Nonetheless, the Smithsonian credited Langley with the historic achievement and ignored the rival Wright brothers all together. This decision rekindled a long-standing fued between the Wrights and Langley that had started during their compeition to build the first manned airplane in the 1890s. Orville Wright was so angered by the Smithsonian's decision that he donated the Wright Flyer to the Science Museum in London, and it was not until his death in 1948 that the Flyer was returned to the United States.
Despite the rather disappointing conclusion to his experiments, Samuel Langley's contributions to the field of
aviation should not be ignored. Though they did not correspond directly with each other due to their rivalry, much
of Langley's research and many of his ideas did influence the Wright brothers and assisted them in their success.
Perhaps more importantly, Langley firmly established the United States as a leader in aerodynamic research and
provided much of the inspiration to construct wind tunnels and other aeronautical laboratories that became crucial
to maintaining American involvement in the new science. It was largely because of this pioneering influence that
the National Advisory Committee on Aeronautics (NACA), the forerunner of NASA, was formed. The new institution
further honored Langley by naming its first major research center the Langley Memorial Laboratory. Today, the
NASA Langley Research Center continues to be a world leader in
aerospace research. The US Navy also paid tribute to Samuel Langley's contibutions to aeronautics when its first
aircraft carrier was named the USS Langley (CV-1) in 1922.
- answer by Jeff Scott, 10 December 2000
Read More Articles:
|Aircraft | Design | Ask Us | Shop | Search|
|About Us | Contact Us | Copyright © 1997-2012|