Samuel Pierpont Langley (1834-1906)

1831 - Walker publishes the first design of a tandem wing aeroplane in the second edition of his Treatise upon the Art of Flying. This almost certainly influence D. S. Brown and through him, Samuel Pierpont Langley 1874 - D. S. Brown completes the tests of his tandem-wing gliders and publishes the results in the Annual Report of the Royal Aeronautical Society for that year. He is concerned with longitudinal stability and was probably inspired by Walker (see 1831). Brown in turn probably was the main influence for Langley (see 1892 and 1896)

Samuel Pierpont Langley

Samuel Pierpont Langley was born in Roxbury, Massachusetts on August 22, 1834. He was educated in the Boston public schools but taught himself engineering as a young adult. He was expert in astronomy, physics, and aeronautics and contributed to the knowledge of solar phenomena. He is best known for his attempts to build the first heavier-than-air flying machine. He became secretary of the Smithsonian Institution in 1887.

It was during his tenure there that he carried out most of his experiments in heavier-than-air flight. Langley began with experiments on flying machines that used twisted rubber bands for propulsion. His larger models used steam engines. He had two successful flights in 1896 with models that caught the eye of the U.S. War Department.

After receiving financial support from the War Department, he built a full-size flying machine called an Aerodrome that was to be piloted. This vehicle used a gasoline-powered internal combustion engine that was built by Charles Manly and was based on an engine built and tested in 1901 by Stephen Balzer. Unfortunately, Langley devoted too much time to the subject of propulsion and not enough to considering the added stresses that would be placed on a large vehicle that was to carry a human passenger.

He attempted twice in 1903 to launch the Aerodrome by catapulting it from the roof of a houseboat anchored in the Potomac River and both attempts failed the aircraft fell apart and plunged into the Potomac. Langley was severely criticized by the press and Congress for his waste of money. He abandoned the effort and died on February 27, 1906.

Timeline : 'Aerodromes' 1892 - 1903

Langley Aerodrome No.1-3, June - Nov.1892

Langley Aerodrome No.4, Dec. 1892 - single wing - initially a failure? heavily modified between 1893-5 to become Aerodrome No.6 in late 1896

Langley Aerodrome No.5, 1896 - nb: 'squared off' wingtips
Copyright © 2000 NASMSI National Air and Space Museum Smithsonian Institution

Wingspan 4.2 m (13 ft. 8 in.), Length 4.03 m (13 ft. 2 in.), Height 1.25 m (4 ft. 1 in.), Weight 11.25 kg (25 lb.)

Langley Aerodrome No.6, 1896 - heavily modified Aerodrome No.4 - nb: rounded wingtips

Wingspan 4.2 m (13 ft 9 in), Length 4.0 m (13 ft 2 in), Height 1.3 m (4 ft 3 in), Weight 11.4 kg (25 lb)

The Quarter Scale Aerodrome, 1901

Wingspan 3.7 m (12 ft), Length 4.7 m (15 ft), Height 1.1 m (3 ft 6 in), Weight 19 kg (42 lb)

Langley Aerodrome A, 1903

Wingspan 14.8 m (48 ft 5 in), Length 16.0 m (52 ft 5 in), Height 3.5 m (11 ft 4 in), Weight 340 kg (750 lb), including pilot

The Curtiss - Langley Aerodrome A (modified), 1914

Wingspan etc...

Timeline : Experiments and supplementary events 1887-1914


Between 1887 and 1891, Langley's staff constructed more than 100 models powered by twisted strands of rubber. None proved capable of staying airborne for more than six seconds. At that juncture, the team investigated every known alternative -- electric motors and batteries, compressed-air motors, hot-water motors and even flywheels. All were too heavy. While carbonic acid (H2CO3) looked promising as a fuel, nagging technical problems dampened enthusiasm for that option. Germany's Nicholas Otto had recently invented an internal combustion engine, but early examples were big, heavy and underpowered.

This era is covered in some detail by David 'Dannysoar' Dodge

Samuel P. Langley's early rubber models

Samuel P. Langley's rubber in tension models

1891 - 95

The First Aerodromes

Lightness, strength and power were prerequisites for successful Aerodromes, and the steam engine seemed to be Langley's last hope. Over the next five years, a tremendous effort was expended to optimize the delicate steam power plant. By 1896, the system consisted of an engine, burner, boiler coils, pump, fuel reservoir and associated delivery tubes and fittings. One example, which produced one brake horsepower, weighed only 7 pounds.

Langley, true to form, avoided theoretical considerations and resorted to empirical methods for determining the airframe design. Large rubber-band-powered test models (Nos. 30 and 31) were used to settle the wing configuration issue. Today those two models would be considered conventional -- a monoplane and a biplane, each equipped with a Cayley-type cruciform tail. Yet a puzzling question remains: How did the final tandem-wing arrangement emerge from those test models? Whatever the reason, all Aerodrome models sported tandem wings.

Work began on the first Aerodrome in November 1891. (Langley's numbering system for identifying the Aerodrome models gets confusing -- his first model was No. 0, the second No. 1, the third No. 2, etc. Later, No. 4 -- the 5th model -- was modified, becoming No. 6.) According to Langley, Aerodrome No.0 had...

"a single pair of large wings containing about 50 square feet, and a smaller one in the rear about half as much, or in all some 75 feet of sustaining surface, for a weight which...would not exceed 25 pounds."

Six months later, that first attempt at a working model was abandoned as hopelessly overweight.

Three new Aerodromes Nos.1, 2 and 3 were built between June and November 1892. Different engines, burners, boilers, fuels, working fluids and a variety of construction materials were tried in the Aerodromes, all in an effort to save weight.

Trial And Error

Determining the ideal size of the Aerodrome was an exercise in trial and error. The second prototype Aerodrome No.1, which was much smaller than its predecessor, was designed to operate on compressed air or H2CO3 acting on the piston of a modified steam engine. Its total supporting surface was only 6.5 square feet, but the engine was weak -- producing only a fraction of the power required for flight.

The third model Aerodrome No.2 was steam-powered. It had a lifting area of 50 square feet and was larger than No. 1 but smaller than No. 0. It also turned out to be overweight and underpowered.

The fourth Aerodrome No.3, about the size of No. 2, showed the best power-to-weight ratio thus far, but Langley was not happy. "There was...," Langley said, "so much that was unsatisfactory about it, that it was deemed best to proceed to another construction before an actual trial was made in the field."

Design and construction of the fifth Aerodrome No.4 began in December 1892. Its relatively small wings totaled 14 square feet, and the weight was a modest 10 pounds. Its power plant and propulsion system lifted 40 percent of the Aerodrome's weight during static tests -- the best performance yet.

Potomac-Based Test Run

Aerodrome No.4 was ready by mid-March 1893, but Langley's crew had difficulty throughout the summer and fall with the complicated overhead launching system. The apparatus used nine sturdy coil springs in tension, operating through two pulleys. A small launching cart, with the Aerodrome hung below, was to accelerate along the 20-foot track. At its end, an automatic release mechanism would free the model, allowing it to proceed in flight.

Langley believed until the end of his life that less power was required to fly faster than slower. In an Aeronautical Annual article, he wrote that...

"it is necessary for an aerodrome, as it is for a soaring bird, to have a certain considerable initial velocity before it can advantageously use its own momentum for flight, and the difficulties of imparting this initial velocity...are surprisingly great."

Believing the power requirements to be unacceptably high at lower velocities, Langley attempted to leapfrog the problem by launching at higher velocities.

Flight testing was always halted during the summer months while Langley and his family vacationed in Europe. By the middle of November 1893, however, everything looked ready for a trial. Aerodrome No.4 was moved from the Smithsonian to the houseboat, anchored on the Potomac off tiny Chopawamsic Island.

Immediately, two problems surfaced. First, in mild breezes, the model swung wildly below the launch cart, jeopardizing a smooth run down the launch rail. Second, the burner -- difficult to maintain in the best of circumstances -- refused to stay lit. No attempt to launch could be made until those problems were corrected by Langley and his assistants. Over the next six weeks, nine round trips were made between the Smithsonian and the houseboat, but all efforts to make the launcher work proved fruitless.

also on the Aerodrome No.4...

Samuel Langley builds Aerodrome No.4 which after major modification becomes in 1896, the successful Aerodrome No.6

In 1887, when Langley became Secretary of the Smithsonian Institution, he began building rubberband-powered toymodels based on experiments conducted by his forerunners in aerodynamics, such as Alphonse Penaud. In 1891 he succeeded in flying one. He continued to experiment by varying the configuration of the wings and by using different type propellers. He eventually constructed between thirty and forty different versions.

Langley hoped to launch a more advanced steam-powered model Aerodrome No.4, weighing a little over 14 pounds, with help from the wind. In 1893, he decided that a launch into the wind would best be accomplished on water, an idea which was being independently developed in Germany by Count Ferdinand von Zeppelin. Langley chose a site on the Potomac River near Quantico, Virginia.

He erected on a fishing scow (12' x 38') a storehouse topped by a four foot high platform. Several attempts with a spring-mounted launching apparatus failed; the following year Langley experimented with a catapult device. This time, however, the wing structure failed due to the weight of the aerodrome. Undaunted, Langley deduced that the aerodrome should have two sets of wings, each of equal area.

Returning to The First Aerodromes

Langley's Frustration

Frustrated and desperate, in January 1894 Langley tried dropping the Aerodrome into a gentle breeze from an arm 25 feet above the water, hoping it would gain flying speed before it reached the river. Its propellers whirled at maximum rpm as Aerodrome No.4 plunged straight into the frigid Potomac.

Another new Aerodrome was almost ready when Langley decided to concentrate his team's effort on the abortive flight tests with Aerodrome No.4. Throughout the winter and spring months of 1894, work proceeded to complete Aerodrome No.5 and retrofit Aerodrome No.4 with a bigger set of wings. Aerodrome No.5 was a large machine, with a wingspan of 13 feet 8 inches, length of 13 feet 2 inches and height of 4 feet 1 inch. Weighing 30 pounds, it was fitted with a new and more powerful single-cylinder steam engine.


Ironic Failure

Over the next five years, Langley developed a scaled-up version of Aerodrome No.5. Powered by a gasoline engine, the "Great Aerodrome" [alt. Aerodrome A - Ed.] experienced similar problems to those of early steam-powered models. On October 7, 1903, the machine snagged on part of the launching mechanism and plunged into the Potomac like "a handful of mortar." Two months later, on December 8, a similar misfortune caused the "Great Aerodrome" to collapse in midair. Fortunately, Langley's chief engineer and designated pilot, Charles Manly, was unhurt in both accidents. But these failures would continue to haunt Langley.

For a full and detialed account of the Aerodrome story, read the full article here


Edward Huffaker begins to work for Samuel Langley, designing wings for Langley's Aerodromes.

Augustus Herring also works briefly for Langley, doing dynamics tests.


On May 6, 1896, Langley's Aerodrome No.5 made the first successful flight of an unpiloted, engine-driven heavier-than-air craft of substantial size. It was launched from a spring-actuated catapult mounted on top of a houseboat on the Potomac River near Quantico, Virginia. Two flights were made that afternoon, one of 1,005 m (3,300 ft) and a second of 700 m (2,300 ft), at a speed of approximately 25 miles per hour. On both occasions, the Aerodrome No.5 landed in the water, as planned, because, in order to save weight, it was not equipped with landing gear.

Aerodrome No.5 had a metal tube-fuselage structure that housed the engine, the boiler, and other components of the propulsion system. The wings and tail were wood-frame, covered with fine silk. The power plant was a single-cylinder, one-horsepower steam engine equipped with a double-action piston with a slide valve, and a flashtube boiler fired by a pressure burner that vaporized gasoline. The engine drove twin propellers, centrally mounted between the front and rear sets of wings, through a system of shafts and bevel gears. The aircraft weighed approximately 11 kg (24.3 lb) ready for flight.

On November 28, 1896, another successful flight was made with a similar model, the Aerodrome No.6. It was flown a distance of approximately 1,460 m (4,790 ft). The Aerodrome No.6 was actually Aerodrome No.4 greatly modified. The original No.4 had been so completely rebuilt between 1893 and 1895 that by then it was referred to as the "new No.4." It was radically altered again in the winter of 1895. This time so little remained of the original aircraft that it was given the new designation of Aerodrome No.6. In appearance, the Aerodrome No.6 was much like the Aerodrome No.5 except for having rounded wing tips. The No.5's wing tips were squared off.

used with permission from the Copyright © 2000 NASMSI National Air and Space Museum Smithsonian Institution



Samuel Langley secures $50,000 funding from the War Department to build a full-size man-carrying Aerodrome by 1899.


Edward Huffaker quits work with Langley and goes back to Tennessee.

The Wright brothers experiment with twisting wings, trying to deform the front edges. They can't come up with a device light enough or strong enough to control a glider in flight.

May 30 - Wilbur Wright writes the Smithsonian asking for published materials on aeronautics. He is answered by Richard Rathbun, who sends four pamphlets and a list of other publications.


Samuel P. Langley : The Quarter Scale 'Aerodrome'
used with permission from the Copyright © 2000 NASMSI National Air and Space Museum Smithsonian Institution

Samuel P. Langley, third Secretary of the Smithsonian Institution, constructed this quarter-scale model of the Aerodrome in 1901. It was one of seven such unmanned powered aircraft he built and flew at the turn of the century. Some had steam engines, others were gasoline powered.

He used this model for balance studies when designing and constructing the full-scale, man-carrying Aerodrome A of 1903. The Quarter-Scale Aerodrome flew twice on June 18, 1901, covering distances of 150 feet (45 meters) and 300 feet (90 meters). Its final flight was in August 8, 1903, when it traveled a distance of 1,000 feet (300 meters)


"The construction details and distribution of stresses on the Aerodrome A were based on the successful performance of a gasoline-powered model, one-fourth the size. This exact scale miniature, known as the Quarter-scale Aerodrome, made two flights of 46 m (150 ft) and 108 m (350 ft) on June 18, 1901, powered by a one-and-a-half horsepower internal combustion engine designed and built by a New York inventor named Stephen M. Balzer"

used with permission from the Copyright © 2000 NASMSI National Air and Space Museum Smithsonian Institution


October 17 - Augustus Herring leaves Kitty Hawk and visits Samuel Langley in Virginia, looking for work. He tells Langley of the Wright's success.

October 19 - Samuel Langley cables the Wrights, requesting information on their "special curved surfaces" and asking to come to Kitty Hawk. The Wrights decline.

December - Samuel Langley asks Octave Chanute to help him get a foot in the door with the Wrights. Chanute can't get them to talk to Langley.


October 7 - Samuel Langley tests his man-carrying Aerodrome on the Potomac, with Charles M. Manly, a co designer, at the controls. The machine snags on its launch mechanism and plunges into the Potomac River.

November 8 - Samuel Langley asks the War Department for more money to rebuild and test his Aerodrome again. He gets it.

December 8 - Samuel Langley tests his Aerodrome again. And again it fails and plunges into the Potomac River. Charles Manly is almost drowned in the crash.


Samuel Langley dies


May 28 - The rehabilitation of the Langley aerodrome at the Curtiss airplane factory is completed, and the aerodrome is successfully launched with Glenn H. Curtiss piloting the craft.


The Curtiss Langley Aerodome Flight, May 28, 1914

Download a 750pixel image


The Curtiss Langley Aerodome Flight, May 28, 1914


The Curtiss Langley Aerodome Flight, May 28, 1914


The Curtiss Langley Aerodome Flight, May 28, 1914


The Curtiss Langley Aerodome Flight, May 28, 1914

Secretary C. D. Walcott provides a controversial statement that the tests thus far have shown that the late Secretary S. P. Langley had succeeded in building the first airplane capable of sustained free flight with a man.


May 28 - In an attempt to nullify the legal decision of Curtiss vs. Wright, Glenn Curtiss "restores" the 1903 Langley Aerodrome and flies it from Lake Keuka ostensibly to prove the Aerodrome was the first airplane capable of manned flight. In reality, Curtiss has made over 30 major modifications to the Aerodrome to make it airworthy. The flights have no effect on the patent litigation.


March 3 - The Langley Aeronautics Laboratory (formerly attached to the Smithsonian) becomes a separate entity, NACA - the National Advisory Committee for Aeronautics. This is the forerunner of NASA.

Annual reports of the Board of Regents of the Smithsonian Institution, Washington DC, 1901

Wright, Wilbur., Annual reports of the Board of Regents of the Smithsonian Institution, Washington DC, 1901 Washington DC: Government Printing Office, 1902.
Professor Samuel Pierpont Langley (1834 - 1906), third Secretary of the Smithsonian Institution, was one of the first major aeronautical figures in the United States. He started serious investigations in flight in 1887 with rubber band-powered models; however, their short and erratic performances led him to seek other types of propulsion.

Unsuccessful experiments were conducted with engines powered by gunpowder, hot water (fireless boiler), compressed air, electricity, and carbon dioxide. In 1892 Langley began experimenting with large tandem-winged models powered by steam engines, and on May 6, 1896, his Aerodrome No. 5 made the first successful flight of any engine driven heavier-than-air craft.

It was launched from a spring-actuated catapult mounted on top of a houseboat on the Potomac River near Quantico, Virginia. Two flights were made during the afternoon, one of 3,300 feet and one of 2,300 feet. On both occasions the Aerodrome landed in the water, as planned, because, in order to save weight, it was not equipped with landing gear.

A distinguished observer, Dr. Alexander Graham Bell, wrote about these flights in Nature on May 28, 1896:

On the occasion referred to, the Aerodrome at a given signal, started from a platform about 20 feet above the water and rose at first directly in the face of the wind, moving at all times with remarkable steadiness, and subsequently swinging around in large curves of, perhaps, a hundred yards in diameter and continually ascending until its steam was exhausted, when at a lapse of about a minute and a half, and at a height which I judge to be between 80 and 100 feet in the air, the wheels ceased turning, and the machine, deprived of the aid of its propellers, to my surprise did not fall but settled down so softly and gently that it touched the water without the least shock, and was in fact immediately ready for another trial.

In the second trial, which followed directly, it repeated in nearly every respect the actions of the first except that the direction of its course was different. It ascended again in the face of the wind afterwards moving steadily and continually in large curves accompanied with a rising motion and a lateral advance. Its motion was, in fact, so steady that I think a glass of water on its surface would have remained unspilled. When the steam gave out again, it repeated for a second time the experience of the first trial when the steam had ceased, and settled gently and easily down.

What height it reached at this trial I cannot say, as I was not so favourably placed as in the first, but I had occasion to notice that this time its course took it over a wooded promontory, and I was relieved of some apprehension in seeing that it was already so high as to pass the tree tops by twenty or thirty feet. It reached the water one minute and thirty-one seconds from the time it started, at a measured distance of over 900 feet from the point at which it rose.

The Dominion of the Air
by J. M. Bacon

Professor Langley, in attacking the same problem, first studied the principle and behaviour of a well-known toy--the model invented by Penaud, which, driven by the tension of india-rubber, sustains itself in the air for a few seconds. He constructed over thirty modifications of this model, and spent many months in trying from these to as certain what he terms the "laws of balancing leading to horizontal flight." His best endeavours at first, however, showed that he needed three or four feet of sustaining surface to a pound of weight, whereas he calculated that a bird could soar with a surface of less than half a foot to the pound.

He next proceeded to steam-driven models in which for a time he found an insuperable difficulty in keeping down the weight, which, in practice, always exceeded his calculation; and it was not till the end of 1893 that he felt himself prepared for a fair trial. At this time he had prepared a model weighing between nine and ten pounds, and he needed only a suitable launching apparatus to be used over water. The model would, like a bird, require an initial velocity imparted to it, and the discovery of a suitable apparatus gave him great trouble. For the rest the facilities for launching were supplied by a houseboat moored on the Potomac. Foiled again and again by many difficulties, it was not till after repeated failures and the lapse of many months, when, as the Professor himself puts it, hope was low, that success finally came. It was in the early part of 1896 that a successful flight was accomplished in the presence of Dr. Bell, of telephone fame, and the following is a brief epitome of the account that this accomplished scientist contributed to the columns of Nature:

"The flying machine, built, apparently, almost entirely of metal, was driven by an engine said to weigh, with fuel and water, about 25 lbs., the supporting surface from tip to tip being 12 or 14 feet. Starting from a platform about 20 feet high, the machine rose at first directly in the face of the wind, moving with great steadiness, and subsequently wheeling in large curves until steam was exhausted, when, from a height of 80 or 100 feet, it shortly settled down. The experiment was then repeated with similar results. Its motion was so steady that a glass of water might have remained unspilled. The actual length of flight each time, which lasted for a minute and a half, exceeded half a mile, while the velocity was between twenty and twenty-five miles an hour in a course that was constantly taking it 'up hill.' A yet more successful flight was subsequently made."

First flights

The Wright Brothers were not alone. Rivalries launched a controversy that left things up in the air for almost half a century

By Frank Wicks - read the complete article here

When we look back at the Wright Brothers' 1903 first flight, from our perspective it is a milestone in human history.

The Wright Brothers were not the first aeronautical engineers in the United States. Technically, they weren't engineers at all by training or according to conventional credentials. But they did what many pundits of their time declared impossible: get a man aloft in a heavier-than-air machine under its own power.


Samuel Pierpont Langley was professor of physics and astronomy at the University of Pittsburgh's Allegheny Observatory, where he had invented instruments for measuring solar radiation. In 1886, the year before he was named secretary of the Smithsonian Institution in Washington, Langley traveled to Buffalo, N.Y., for a meeting of the American Association for the Advancement of Science. He attended lectures on flight and would devote much of his remaining years to the challenge.

When he secured research funds, Langley began to measure how much power was required to lift a weight with a wing moving through the air. He used a technique for testing air foils that had been described 50 years earlier by Sir George Cayley. A wing could be attached to a 30-foot-long arm rotating at up to 70 miles per hour on a horizontal plane.

The lift and drag forces were difficult to measure. In an 1891 paper, "Experiments in Aerodynamics," Langley concluded the higher the speed, the lower the drag. This incorrect conclusion was accepted at the time and named Langley's Law. He experimented with models that used two wings in tandem with a propeller powered by a small steam engine.

Langley was joined by Alexander Graham Bell who, 20 years after he invented the telephone, said he was more interested in flight. Langley achieved a remarkably successful flight on May 16, 1896, when his fifth model traveled 3,300 feet in a circular path at a speed of about 25 mph before running out of fuel.

Langley and Bell were elated. The aircraft weighed 30 pounds and had a 7-foot wing span. It was powered by a 1-hp steam engine with a boiler pressure of 90 psi driving the propeller at 700 rpm. For the first time, a large model with a self-contained power plant had demonstrated heavier-than-air flight.

That was the year in which William McKinley was elected president, and he appointed the young Theodore Roosevelt assistant secretary of the Navy. When the war against Spain materialized after the sinking of the battleship Maine in Havana Harbor, the United States suddenly became a world power.

Langley solicited McKinley and Roosevelt for funds to construct a man-carrying flying machine for future military missions. In 1898, Congress authorized $50,000 for the project.

Langley understood a practical machine that could carry a human over a significant distance could not be powered by steam engines.

It was still eight years before Henry Ford would introduce the Model T as the first mass-produced automobile, but gasoline engines were beginning to compete with steam and electric for the few customized cars that existed. Langley estimated that human flight would require an engine of at least 12 hp.

In 1899, his friend Robert Thurston, a Cornell engineering professor, introduced him to Charles Manly, who had graduated from Cornell as a mechanical engineer.

Manly went to work for Langley. He modified a 6-hp engine that had five rotating air-cooled cylinders and a fixed crankshaft to a radial engine with fixed cylinders and a rotating crankshaft. Next, he converted from air to water cooling by adding jackets to the cylinders. By June 1901, he had nearly quadrupled the output to 22 hp.

Manly increased displacement from 380 to 540 cubic inches, which required casting new cylinders and cooling jackets. He improved the ignition and carburetor. By March 1903, in static tests the 130-lb. engine produced 52 hp as it turned twin propellers at 575 rpm.

After 17 years, Langley's dream of powered human flight finally seemed attainable. The first manned flight, on Oct. 7, 1903, would be launched by a 60-foot catapult from the roof of a houseboat that also served as a machine shop anchored on the Potomac River. Reporters, photo-graphers, and sightseers turned out in hopes of witnessing history. Manly, the pilot, had strapped a compass to his leg to aid in navigating a long flight.

Manly took his place at the controls. The unmuffled engine was running smoothly. The launch signal was the firing of two rockets followed by two toots from a tugboat. A mechanic cut the holding cable. The catapult moved the plane forward. There was a roaring and grinding noise as the airship tumbled 16 feet into water.

Manly was unhurt. Langley blamed a fouled launching mechanism. They tried and failed again on December 8. On this launch, the nose angled up before the splashdown. This time, Manly barely survived and the aircraft was badly damaged. It is improbable that the necessary flying speed was achieved.

Members of Congress and the press began to call it Langley's Folly. The government withdrew support. Langley had to abandon his dream and died in 1906.

Many experts were skeptical that flight was even possible. Admiral George Melville, the Navy's chief engineer and a president of ASME, received acclaim for his vision of converting ship propulsion from reciprocating steam engines to the newly developed turbines. When it came to the possibilities of human flight, the admiral was a skeptic who wrote with authority. He had written about flight in the December 1901 issue of North American Review that "a calm survey of natural phenomena leads the engineer to pronounce all confident prophecies for future success as wholly unwarranted, if not absurd."

An editorial in The New York Times said Langley's fiasco was not unexpected by experts because of the existing relationship between the weight and strength of materials. The editorial predicted that a flying machine might take a million years of efforts by mathematicians and mechanicians.

It actually took nine days after Langley's final failure. The flying machine that Wilbur and Orville Wright had developed with their own funds performed the epic feat on Dec. 17, 1903. Attention was minimal. It was not reported by The New York Times. There were only five witnesses and a camera.

The Wright Brothers logged air time in gliders before they tried a self-powered craft. Dan Tate (left) and E.C. Huffaker launched Wilbur Wright in 1901.

The brothers' success immediately after Langley's well-funded failure was astonishing. Neither brother was a high school graduate. It was suggested that they stumbled into the sky almost by accident.

However, the revised view of present-day historians of science and technology is that Wilbur and Orville Wright were possibly the most remarkable scientific and engineering team in history. Their work has become a favored topic for engineering case studies.


Langley, with the help of Manly, had spent five years with government funding to successfully modify an existing engine to produce 52 hp and weigh only 130 lbs. With the improved wing performance, Wilbur calculated that only 8 hp was required for level flight. In their bicycle shop during the winter and spring of 1903, the brothers designed and built a workable 160-lb. engine that produced 16 hp when cold but deteriorated to 12 hp when hot.

The 200-cubic-inch engine contained four inline horizontal water-cooled cylinders with a 4-inch bore and stroke. There was no fuel pump, water pump, radiator, carburetor, spark plugs, or exhaust pipes. Gasoline flowed by gravity directly into the intake, where it was vaporized by incoming air. Water was allowed to boil in the jacket around the cylinders. The spark was produced by opening electric contacts inside the cylinder via a cam. Electricity was induced in a stationary coil by a magnet mounted on the 26-lb. engine flywheel.


Why did Wilbur and Orville Wright succeed instead of Samuel Langley, who as the secretary of the Smithsonian, was the nation's most eminent scientist and had the advantages of time, government funding, and outstanding engineering support? That question is best answered by examining the five conditions that were necessary for success: adequate lift, thrust, control, flying skill, and launching.

Langley's wings and structure were adequate in terms of lift and strength, but the Wrights had a better design. Langley had the much superior engine. The brothers had invented and implemented three-axis control. Manly had no piloting experience, while Wilbur and Orville had become highly skilled pilots with their 1902 glider. Langley's technique of catapult launching from the roof of a houseboat was unforgiving, while the Wrights' technique of launching with skids on the sand allowed for several initial failures and adjustments before their final success.


Langley's engineer, Charles Manly, was recruited by Curtiss. Bell believed that the Langley machine, then in storage at the Smithsonian, was capable of flight. Curtiss understood that if the Langley machine could fly, it would weaken the Wrights' patent claims.

The new Smithsonian secretary, Charles Walcott, allowed Curtiss to borrow the Langley machine. It was restored and modified. Curtiss installed floats and, in 1914, lifted the Langley machine off Keuka Lake for a flight of about 150 feet. Langley's Folly finally flew, 11 years after its second splash in the Potomac.


Frank Wicks is a professor of mechanical engineering at Union College in Schenectady, N.Y., and is a pilot of gliders and powered aircraft.

Enduring Heritage

The Virginia Air and Space Center is home to the Great Aerodrome, which almost beat the Wrights into the air

By Donald L. Lansing

which in part says...

Langley's interest in aviation blossomed when he was 52, just before he joined the Smithsonian Institution as its new secretary. By then, Langley had an established international reputation as a solar physicist. He had invented an instrument, the bolometer, for measuring the spectral distribution of the sun's radiant energy. He studied the then-unexplored infrared portion of the sun's radiation and made the first attempt to estimate the solar constant--the rate at which the earth receives energy from the sun--a critical determinant of our climate and growing seasons. For that pioneering work, Langley received numerous medals, awards and honorary doctorates from scientific societies and universities in the United States and abroad.

In 1891, Langley began to build large, steam-powered, unmanned models of heavier-than-air flying machines, which he called "aerodromes." Seven aerodromes subsequently were constructed, numbered 0 to 6. Each was different, but typically weighed 20 pounds, was 16 feet long and had a 12-foot wingspan. They had a unique tandem-wing configuration with four wings of identical shape, two forward and two aft. Two pusher propellers were each powered by a small 1-horsepower, alcohol-fueled steam engine. The aerodromes, which were completely uncontrolled in flight, were launched with a spring-loaded catapult from the top of a houseboat anchored in the Potomac River near Quantico, Va. The river offered an unobstructed flyover area and a large landing area.

On May 6, 1896, Langley successfully flew aerodrome No. 5 twice. A third successful flight was achieved on November 28 with aerodrome No. 6. Those flights lasted about 90 seconds while covering circular paths of between one-half and one mile. On the basis of those flights, Langley deservedly receives credit for having achieved the world's first sustained flights of heavier-than-air flying machines, even though they were unmanned.

With those successes behind him, Langley was ready to embark on his most ambitious undertaking--building a man-carrying flying machine, which would become known as his "Great Aerodrome" [alt. Aerodrome A - Ed.]. The project would be costly, so he set out to obtain government money. The Spanish-American War erupted in April 1898, so the War Department became interested in his proposed vehicle as an observation platform. The War Department awarded him $50,000 in late 1898 to cover expenses. Langley would use another $23,000 of Smithsonian discretionary funds, which he controlled, before the project was complete.

Because he had a winning approach in the small aerodromes, Langley simply scaled everything up, making necessary allowance for the presence of an onboard aviator. The Great Aerodrome would be catapulted from the top of a new and larger houseboat. It took Langley almost five hours to remove the Great Aerodrome from storage, raise each piece to the top of the shed and fully assemble the machine on the catapult. Summer thunderstorms frequently disrupted those time-consuming preparations.

The development of a suitable engine to power the dual pusher propellers proved to be a major frustration; 41?2 years passed before a suitable engine was developed by Charles Manly, an engineer on Langley's team, in the Smithsonian shops. It delivered 52 hp at a weight of approximately 200 pounds. By contrast, the Wright brothers' 180-pound (and thoroughly adequate) engine delivered only 12 hp. Manly's engine was the highest performance gasoline engine of its day, and was one of the true achievements of the Great Aerodrome project.

Like the earlier small versions, the Great Aerodrome was again a tandem-wing, dual pusher propeller configuration. It measured 55 feet in overall length and 48 feet in wingspan. The frail, lightweight structure was braced by a complex system of support wires radiating from four guy posts. One engine drove both propellers through an array of shafts and gears. An aviator's car was added to accommodate the pilot. Rudimentary controls consisted of an engine throttle, a vertical, wedge-shaped rudder for yaw control, and a large cruciform tail for pitch control. Like some other would-be aviators of the day, Langley thought that a human pilot could not react quickly enough to unpredictable upper air currents in order to completely control a flying machine. Hence, he installed no lateral (roll) control--inherent stability was to be assured by wing dihedral. Landing gear was conspicuously absent. The aviator--Manly volunteered for the honor--would just have to know how to swim! There were floats located about the airframe to prevent it from sinking. The Great Aerodrome, including pilot, weighed 850 pounds. By comparison, the 1903 Wright Flyer weighed 750 pounds including pilot. It was a biplane 40 feet in span, 21 feet in overall length, and incorporated a fully tested three-axis control system that, as the Wrights well understood, was the outstanding challenge to manned flight at that time.

In the fall of 1903, everything was ready. By now Langley was feeling intense pressure to show results. He was running out of money, there was no war to sustain government interest in the work, and the media wanted to know what the country was getting for the taxpayers' money. During the first flight test on October 7, the Great Aerodrome shot off the catapult and immediately nosed down into the Potomac "like a handful of mortar." The floating debris was gathered up and taken back to the Smithsonian shops. The damage was actually not serious. The aerodrome was repaired and taken out for another flight on December 8. There was no time to tow the houseboat downriver from Washington to Quantico, so the test took place off of what is now Washington National Airport in full view of the press and public. This time, immediately after launch, the Great Aerodrome nosed up, fell over onto its back and crashed into the now cold and icy river. Remarkably, Manly survived unharmed but well chilled. A generous ration of spirits and expletives brought about his swift recovery.

The media and Congress had a field day at the expense of the "professor... wandering in his dreams of flight...who was given to building...castles in the air." One congressman was quoted as saying, "You tell Langley for me...that the only thing he ever made fly was government money." The appropriateness of spending public funds on that kind of high-risk research was openly debated. And then, as if to deliberately aggravate an already tender wound, the Wright brothers conducted their first four successful flights at Kitty Hawk, N.C., only nine days later--on December 17.

As secretary of the Smithsonian, Langley was, in effect, the nation's chief scientist. Consequently, all the open criticism and public ridicule had a devastating effect on his image and self-esteem. After he died, disheartened and disgraced, in February 1906, Langley was identified with the failure of his Great Aerodrome--his other substantial and lasting accomplishments being overlooked and largely forgotten.

What went wrong? Langley blamed the launch mechanism for the failures. A friend of Orville Wright, Griffith Brewer, dismissed that explanation as little more than an unsupportable excuse. While modern-day aerodynamicists differ somewhat on the details, they agree that the Aerodrome's flimsy structure was unable to support the transient aerodynamic loads induced on it by the catapult-type launch. The Langley team did not have the scientific understanding or the engineering insight to achieve the dream of "navigating the air." There was much about aerodynamics and flying that Langley never mastered.

The Great Aerodrome did not pass into oblivion after the 1903 disaster, however. It reappeared in 1914 to become the centerpiece in a long and drawn out public controversy between the Smithsonian and Orville Wright (Wilbur had died of typhoid in 1912) over who invented the first operational airplane. In 1914, the Smithsonian awarded Glenn Curtiss, one of the great innovators and promoters of early aviation who flew after and competed with the Wrights, a $2,000 contract to fly the Great Aerodrome to settle the still unanswered question of whether or not it would have been capable of sustained, piloted flight. The Great Aerodrome was shipped to the Curtiss aircraft factory at Hammondsport, N.Y., where it was extensively modified and rebuilt by his mechanics and actually flown on several short hops over Keuka Lake. The machine was then returned to the Smithsonian and restored to its 1903 condition.

On the basis of the flights of the altered machine, the Great Aerodrome was put on display at the Smithsonian with an exhibit label asserting that it "was the first man-carrying aeroplane in the history of the world capable of sustained free flight." The Smithsonian's 1914 annual report stated that the Great Aerodrome of 1903, "with its original structure and power," was "capable of flying with a pilot and several hundred pounds of useful load." The Wright Flyer was shipped to England for display.

Orville Wright asked the Smithsonian to clarify its claims, initiating a public dispute that was to harm the institution's credibility and tarnish its reputation for objective scholarship. The controversy would not be fully and finally settled to everyone's satisfaction for 34 years. In 1942, the Smithsonian published a short paper, reviewed and approved by Orville Wright, that confessed the institution's sins in the most diplomatic terms. That paper defused the controversy and paved the way for the eventual reconciliation between Orville Wright and the Smithsonian.

On December 17, 1948--45 years to the hour after the Wright brothers' first flights--the restored 1903 Wright Flyer was returned to public display in an elaborate ceremony at the Smithsonian's Arts and Industries Building. The personalities and events of that controversy, characterized by Griffith Brewer in the 1920s as "the greatest scandal in aviation history," make a fascinating sidelight to aviation legend that readers will find described in biographies of Langley, Curtiss and the Wright brothers.

'Memoir on Mechanical Flight'
Langley, Samuel Pierpont and Manly, Charles M[atthews]

Memoir on Mechanical Flight, Part I, 1887 to 1896, by Samuel Pierpont Langley, edited by Charles M. Manly. Part II, 1897 TO 1903, by Charles M. Manly, Assistant in Charge of Experiments. (Publication 1948). Washington, Smithsonian, 1911. x,[2],320pp. Illus., 101 plates, some double-page. Original 4to printed wrappers. First edition. Smithsonian Contributions to Knowledge, Volume 27, Number 3.

This volume, which follows his Experiments in aeronautics (1891) and The internal work on the wind, (1893) was published following his death in 1906. It documents in great detail his experiments with gliders and powered models as well as his later ill-fated Aerodrome.

In 1898 Langley was requested by the U.S. War Department to design and construct a man-carrying Aerodrome, a term chosen by Langley to call his aircraft. The years 1899 to 1903 were spent in the design, testing and construction of the craft. The actual trials took place on a houseboat on the Potomac River on October 7 and December 8, 1903.

With his assistant Charles M. Manly at the controls a launch was made via a catapult atop the houseboat. A malfunction in the launching apparatus caused the machine to crash a few feet in front of the boat wrecking the Aerodrome and also Langley's experiments as the U.S. government withdrew financial support.

It is unknown if Langley's aircraft would have flown were it not for the launching problem. It was academic, for nine days later on December 17, 1903, the Wright Brothers became the first to fly in a powered aircraft. Langley however is credited with proving that this could be achieved via his extensive experiments with models in sustained flight.

Story of Experiments in Mechanical Flight By Samuel Pierpont Langley from James Means' 1897 Aeronautical Annual

The editor of "The Annual" has asked me to give matter of a somewhat personal nature for a narrative account of my work in aerodromics.

The subject of flight interested me as long ago as I can remember anything, but it was a communication from Mr. Lancaster, read at the Buffalo meeting of the American Association for the Advancement of Science, in 1886, which aroused my then dormant attention to the subject. What he said contained some remarkable but apparently mainly veracious observations on the soaring bird, and some more or less paradoxical assertions, which caused his communication to be treated with less consideration than it might otherwise have deserved. Among these latter was a statement that a model, somewhat resembling a soaring bird, wholly inert, and without any internal power, could, nevertheless, under some circumstances advance against the wind without falling; which seemed to me then, as it did to members of the Association, an utter impossibility, but which I have since seen reason to believe is, within limited conditions, theoretically possible.

I was then engaged in the study of astro-physics at the Observatory in Allegheny, Pennsylvania. The subject of mechanical flight could not be said at that time to possess any literature, unless it were the publications of the French and English aeronautical societies, but in these, as in everything then accessible, fact had not yet always been discriminated from fancy. Outside of these, almost everything was even less trustworthy; but though after I had experimentally demonstrated certain facts, anticipations of them were found by others on historical research, and though we can now distinguish in retrospective examination what would have been useful to the investigator if he had known it to be true, there was no test of the kind to apply at the time. I went to work, then, to find out for myself, and in my own way, what amount of mechanical power was requisite to sustain a given weight in the air, and make it advance at a given speed, for this seemed to be an inquiry which must necessarily precede any attempt at mechanical flight, which was the very remote aim of my efforts.

The work was commenced in the beginning of 1887 by the construction, at Allegheny, of a turn-table of exceptional size, driven by a steam-engine, and this was used during three years in making the Experiments in Aerodynamics, which were published by the Smithsonian Institution, under that title, in 1891. Nearly all the conclusions reached were the result of direct experiment in an investigation which aimed to take nothing on trust. Few of them were then familiar, though they have since become so, and in this respect knowledge has advanced so rapidly that statements which were treated as paradoxical on my first enunciation of them are now admitted truisms.

It has taken me, indeed, but a few years to pass through the period when the observer hears that his alleged observation was a mistake; the period when he is told that if it were true, it would be useless; and the period when he is told that it is undoubtedly true, but that it has always been known.

May I quote from the introduction to this book what was said in 1891?

"I have now been engaged since the beginning of the year 1887 in experiments on an extended scale for determining the possibilities of, and the conditions for, transporting in the air a body whose specific gravity is greater than that of the air, and I desire to repeat my conviction that the obstacles in its way are not such as have been thought; that they lie more in such apparently secondary difficulties as those of guiding the body so that it may move in the direction desired, and ascend or descend with safety, than in what may appear to be the primary difficulties due to the nature of the air itself," and, I added, that in this field of research I thought that we were, at that time (only six years since), "in a relatively less advanced condition than the study of steam was before the time of Newcomen."

It was also stated that the most important inference from those experiments as a whole was that mechanical flight was possible with engines we could then build, as one-horse power rightly applied could sustain over 200 pounds in the air at a horizontal velocity of somewhat over 60 feet a second.

As this statement has been misconstrued, let me point out that it refers to surfaces, used without guys, or other adjuncts, which would create friction; that the horse-power in question is that actually expended in the thrust, and that it is predicated only on a rigorously horizontal flight. This implies a large deduction from the power in the actual machine, where the brake horse-power of the engine, after a requisite allowance for loss in transmission to the propellers, and for their slip on the air, will probably be reduced to from one-half to one-quarter of its nominal amount; where there is great friction from the enforced use of guys and other adjuncts; but above all where there is no way to insure absolutely horizontal flight in free air. All these things allowed for, however, since it seemed to me possible to provide an engine which should give a horse-power for something like 10 pounds of weight, there was still enough to justify the statement that we possessed in the steam-engine, as then constructed, or in other heat engines, more than the indispensable power, though it was added that this was not asserting that a system of supporting surfaces could be securely guided through the air or safely brought to the ground, and that these and like considerations were of quite another order, and belonged to some inchoate art which I might provisionally call aerodromics.

These important conclusions were reached before the actual publication of the volume, and a little later others on the nature of the movements of air, which were published under the title of The Internal Work of the Wind (Smithsonian Contributions to Knowledge, Volume XXVII., 1893, No. 884). The latter were founded on experiments independent of the former, and which led to certain theoretical conclusions unverified in practice. Among the most striking and perhaps paradoxical of these, was that a suitably disposed free body might under certain conditions be sustained in an ordinary wind, and even advance against it without the expenditure of any energy from within.

The first stage of the investigation was now over, so far as that I had satisfied myself that mechanical flight was possible with the power we could hope to command, if only the art of directing that power could be acquired.

The second stage (that of the acquisition of this art) I now decided to take up. It may not be out of place to recall that at this time, only six years ago, a great many scientific men treated the whole subject with entire indifference as unworthy of attention or as outside of legitimate research, the proper field for the charlatan, and one on which it was scarcely prudent for a man with a reputation to lose, to enter.

The record of my attempts to acquire the art of flight may commence with the year 1889, when I procured a stuffed frigate bird, a California condor, and an albatross, and attempted to move them upon the whirling table at Allegheny. The experiments were very imperfect and the records are unfortunately lost, but the important conclusion to which they led was that a stuffed bird could not be made to soar except at speeds which were unquestionably very much greater than what served to sustain the living one, and the earliest experiments and all subsequent ones with actually flying models have shown that thus far we cannot carry nearly the weights which Nature does to a given sustaining surface, without a power much greater than she employs. At the time these experiments were begun, Penaud's ingenious but toy-like model was the only thing which could sustain itself in the air for even a few seconds, and calculations founded upon its performance sustained the conclusion that the amount of power required in actual free flight was far greater than that demanded by the theoretical enunciation. In order to learn under what conditions the aerodrome should be balanced for horizontal flight, I constructed over 30 modifications of the rubber-driven model, and spent many months in endeavoring from these to ascertain the laws of "balancing"; that is, of stability leading to horizontal flight. Most of these models had two propellers, and it was extremely difficult to build them light and strong enough. Some of them had superposed wings; some of them curved and some plane wings; in some the propellers were side by side, in others one propeller was at the front and the other at the rear, and so every variety of treatment was employed, but all were at first too heavy, and only those flew successfully which had from 3 to 4 feet of sustaining surface to a pound of weight, a proportion which is far greater than Nature employs in the soaring bird, where in some cases less than half a foot of sustaining surface is used to a pound. It had been shown in the Experiments in Aerodynamics that the centre of pressure on an inclined plane advancing was not at the centre of figure, but much in front of it, and this knowledge was at first nearly all I possessed in balancing these early aerodromes. Even in the beginning, also, I met remarkable difficulty in throwing them into the air, and devised numerous forms of launching apparatus which were all failures, and it was necessary to keep the construction on so small a scale that they could be cast from the hand.

The earliest actual flights with these were extremely irregular and brief, lasting only from three to four seconds. They were made at Allegheny in March, 1891, but these and all subsequent ones were so erratic and so short that it was possible to learn very little from them. Penaud states that he once obtained a flight of 13 seconds. I never got as much as this, but ordinarily little more than half as much, and came to the conclusion that in order to learn the art of mechanical flight it was necessary to have a model which would keep in the air for at any rate a longer period than these, and move more steadily. Rubber twisted in the way that Penaud used it, will practically give about 300 foot-pounds to a pound of weight, and at least as much must be allowed for the weight of the frame on which the rubber is strained. Twenty pounds of rubber and frame, then, would give 3,000 foot-pounds, or one-horse power for less than six seconds. A steam-engine, having apparatus for condensing its steam, weighing in all 10 pounds and carrying 10 pounds of fuel, would possess in this fuel, supposing that but one-tenth of its theoretical capacity is utilized, many thousand times the power of an equal weight of rubber, or at least one-horse power for some hours. Provided the steam could be condensed and the water re-used, then, the advantage of the steam over the spring motor was enormous, even in a model constructed only for the purpose of study. But the construction of a steam-driven aerodrome was too formidable a task to be undertaken lightly, and I examined the capacities of condensed air, carbonic acid gas, of various applications of electricity, whether in the primary or storage battery, of hot-water engines, of inertia motors, of the gas engine, and of still other material. The gas engine promised best of all in theory, but it was not yet developed in a suitable form. The steam-engine, as being an apparently familiar construction, promised best in practice, but in taking it up, I, to my cost, learned that in the special application to be made of it, little was really familiar and everything had to be learned by experiment. I had myself no previous knowledge of steam engineering, nor any assistants other than the very capable workmen employed. I well remember my difficulties over the first aerodrome (No. 0), when everything, not only the engine, but the boilers which were to supply it, the furnaces which were to heat it, the propellers which were to advance it, the hull which was to hold all these,-were all things to be originated, in a construction which, as far as I knew, had never yet been undertaken by any one.

It was necessary to make a beginning, however, and a compound engine was planned which, when completed, weighed about 4 pounds, and which could develop rather over a horse-power with 60 pounds of steam, which it was expected could be furnished by a series of tubular boilers arranged in "bee-hive" form, and the whole was to be contained in a hull about 5 feet in length and 10 inches in diameter. This hull was, as in the construction of a ship, to carry all adjuncts. In front of it projected a steel rod, or bowsprit, about its own length, and one still longer behind. The engines rotated two propellers, each about 30 inches in diameter, which were on the end of long shafts disposed at an acute angle to each other and actuated by a single gear driven from the engine. A single pair of large wings contained about 50 square feet, and a smaller one in the rear about half as much, or in all some 75 feet, of sustaining surface, for a weight which it was expected would not exceed 25 pounds.

Although this aerodrome was in every way a disappointment, its failure taught a great many useful lessons. It had been built on the large scale described, with very little knowledge of how it was to be launched into the air, but the construction developed the fact that it was not likely to be launched at all, since there was a constant gain in weight over the estimate at each step, and when the boilers were completed, it was found that they gave less than one-half the necessary steam, owing chiefly to the inability to keep up a proper fire. The wings yielded so as to be entirely deformed under a slight pressure of the air, and it was impossible to make them stronger without making them heavier, where the weight was already prohibitory. The engines could not transmit even what feeble power they furnished, without dangerous tremor in the long shafts, and there were other difficulties. When the whole approached completion, it was found to weigh nearer 50 pounds than 25, to develop only about one-half the estimated horsepower at the brake, to be radically weak in construction, owing to the yielding of the hull, and to be, in short, clearly a hopeless case.

The first steam-driven aerodrome had, then, proved a failure, and I reverted during the remainder of the year to simpler plans, among them one of an elementary gasolene engine.

I may mention that I was favored with an invitation from Mr. Maxim to see his great flying-machine at Bexley, in Kent, where I was greatly impressed with the engineering skill shown in its construction, but I found the general design incompatible with the conclusions that I had reached by experiments with small models, particularly as to what seemed to me advisable in the carrying of the centre of gravity as high as was possible with safety.

In 1892 another aerodrome (No. 1), which was to be used with carbonic acid gas, or with compressed air, was commenced. The weight of this aerodrome was a little over four and a half pounds, and the area of the supporting surfaces six and a half square feet. The engines developed but a small fraction of a horse-power, and they were able to give a dead lift of only about one-tenth of the weight of the aerodrome, giving relatively less power to weight than that obtained in the large aerodrome already condemned.

Toward the close of this year was taken up the more careful study of the position of the centre of gravity with reference to the line of thrust from the propellers, and to the centre of pressure. The centre of gravity was carried as high as was consistent with safety, the propellers being placed so high, with reference to the supporting wings, that the intake of air was partly from above and partly from below these latter. The lifting power (i.e., the dead-lift) of the aerodromes was determined in the shop by a very useful contrivance which I have called the "pendulum," which consists of a large pendulum which rests on knife edges, but is prolonged above the points of support, and counterbalanced so as to present a condition of indifferent equilibrium. Near the lower end of this pendulum the aerodrome is suspended, and when power is applied to it, the reaction of the propellers lifts the pendulum through a certain angle. If the line of thrust passes through the centre of gravity, it will be seen that the sine of this angle will be the fraction of the weight lifted, and thus the dead-lift power of the engines becomes known. Another aerodrome was built, but both, however constructed, were shown by this pendulum test to have insufficient power, and the year closed with disappointment.

Aerodrome No. 3 was of stronger and better construction, and the propellers, which before this had been mounted on shafts inclined to each other in a V-like form, were replaced by parallel ones. Boilers of the Serpolet type (that is, composed of tubes of nearly capillary section) were experimented with at great cost of labor and no results; and they were replaced with coil boilers. For these I introduced, in April, 1893, a modification of the ælopile blast, which enormously increased the heat-giving power of the fuel (which was then still alcohol), and with this blast for the first time the boilers began to give steam enough for the engines. It had been very difficult to introduce force pumps which would work effectively on the small scale involved, and after many attempts to dispense with their use by other devices, the acquisition of a sufficiently strong pump was found to be necessary in spite of its weight, but was only secured after long experiment. It may be added that all the aerodromes from the very nature of their construction were wasteful of heat, the industrial efficiency little exceeding half of one per cent., or from one-tenth to one-twentieth that of a stationary engine constructed under favorable conditions. This last aerodrome lifted nearly 30 per cent. of its weight upon the pendulum, which implied that it could lift much more than its weight when running on a horizontal track, and its engines were capable of running its 50-centimetre propellers at something over 700 turns per minute. There was, however, so much that was unsatisfactory about it, that it was deemed best to proceed to another construction before an actual trial was made in the field, and a new aerodrome, designated as No. 4, was begun. This last was an attempt, guided by the weary experience of preceding failures, to construct one whose engines should run at a much higher pressure than heretofore, and be much more economical in weight. The experiments with the Serpolet boilers having been discontinued, the boiler was made with a continuous helix of copper tubing, which as first employed was about three millimetres internal diameter; and it may be here observed that a great deal of time was subsequently lost in attempts to construct a more advantageous form of boiler for the actual purposes than this simple one, which with a larger coil tube eventually proved to be the best; so that later constructions have gone back to this earlier type. A great deal of time was lost in these experiments from my own unfamiliarity with steam engineering, but it may also be said that there was little help either from books or from counsel, for everything was here sui generis, and had to be worked out from the beginning. In the construction which had been reached by the middle of the third year of experiment, and which has not been greatly differed from since, the boiler was composed of a coil of copper in the shape of a hollow helix, through the centre of which the blast from the ælopile was driven, the steam and water passing into a vessel I called the "separator," whence the steam was led into the engines at a pressure of from 70 to 100 pounds (a pressure which has since been considerably exceeded).

From the very commencement of this long investigation the great difficulty was in keeping down the weight, for any of the aerodromes could probably have flown had they been built light enough, and in every case before the construction was completed the weight had so increased beyond the estimate, that the aerodrome was too heavy to fly, and nothing but the most persistent resolution kept me in continuing attempts to reduce it after further reduction seemed impossible. Toward the close of the year (1893) I had, however, finally obtained an aerodrome with mechanical power, as it seemed to me, to fly, and I procured, after much thought as to where this flight should take place, a small house-boat, to be moored somewhere in the Potomac; but the vicinity of Washington was out of the question, and no desirable place was found nearer than thirty miles below the city. It was because it was known that the aerodrome might have to be set off in the face of a wind, which might blow in any direction, and because it evidently was at first desirable that it should light in the water rather than on the land, that the house-boat was selected as the place for the launch. The aerodrome (No. 4) weighed between 9 and 10 pounds, and lifted 40 per cent. of this on the pendulum with 60 pounds of steam pressure, a much more considerable amount than was theoretically necessary for horizontal flight. And now the construction of a launching apparatus, dismissed for some years, was resumed. Nearly every form seemed to have been experimented with unsuccessfully in the smaller aerodromes. Most of the difficulties were connected with the fact that it is necessary for an aerodrome, as it is for a soaring bird, to have a certain considerable initial velocity before it can advantageously use its own mechanism for flight, and the difficulties of imparting this initial velocity with safety are surprisingly great, and in the open air are beyond all anticipation.

Here, then, commences another long story of delay and disappointment in these efforts to obtain a successful launch. To convey to the reader an idea of its difficulties, a few extracts from the diary of the period are given. (It will be remembered that each attempt involved a journey of thirty miles each way.)

Nov. 18, 1893. Having gone down to the house-boat, preparatory to the first launch, in which the aerodrome was to be cast from a springing piece beneath, it was found impossible to hold it in place on this before launching, without its being prematurely torn from its support, although there was no wind except a moderate breeze; and the party returned after a day's fruitless effort.

Two days later a relative calm occurred in the afternoon of a second visit, when the aerodrome was mounted again, but, though the wind was almost imperceptible, it was sufficient to wrench it about so that at first nothing could be done, and when steam was gotten up, the burning alcohol blew about so as to seriously injure the inflammable parts. Finally, the engines being under full steam, the launch was attempted, but, owing to the difficulties alluded to and to a failure in the construction of the launching piece, the aerodrome was thrown down upon the boat, fortunately with little damage.

Whatever form of launch was used it became evident at this time that the aerodrome must at any rate be firmly held, up to the very instant of release, and a device was arranged for clamping, it to the launching apparatus.

On November 24th another attempt was made to launch, which was rendered impossible by a very moderate wind indeed.

On November 27th a new apparatus was arranged to merely drop the aerodrome over the water, with the hope that it would get up sufficient speed before reaching the surface to soar, but it was found that a very gentle intermittent breeze (probably not more than three or four miles an hour) was sufficient to make it impossible even to prepare to drop the aerodrome toward the water with safety.

It is difficult to give an idea in few words of the nature of the trouble, but unless one stands with the machine in the open air he can form no conception of what the difficulties are which are peculiar to practice in the open, and which do not present themselves to the constructor in the shop, nor probably to the mind of the reader.

December 1st, another failure; December 7th, another; December 11th, another; December 20th, another; December 21st, another. These do not all involve a separate journey, but five separate trips were made of a round distance of 60 miles each before the close of the season. It may be remembered that these attempts were in a site far from the conveniences of the workshop, and under circumstances which took up a great deal of time, for some hours were spent on mounting the aerodrome on each occasion, and the year closed without a single cast of it into the air. It was not known how it would have behaved there, for there had not been a launch, even, in nine trials, each one representing an amount of trouble and difficulty which this narrative gives no adequate idea of.

I pass over a long period of subsequent baffled effort, with the statement that numerous devices for launching were tried in vain, and that nearly a year passed before one was effected.

Six trips and trials were made in the first six months of 1894, without securing a launch. On the 24th of October a new launching piece was tried for the first time, which embodied all the requisites whose necessity was taught by previous experience, and, saving occasional accidents, the launching was from this time forward accomplished with comparatively little difficulty.

The aerodromes were now for the first time put fairly in the air, and a new class of difficulties arose, due to a cause which was at first obscure,-for two successive launches of the same aerodrome, under conditions as near alike as possible, would be followed by entirely different results. For example, in the first case it might be found rushing, not falling, forward and downward into the water under the impulse of its own engines; in the second case, with every condition from observation apparently the same, it might be found soaring upward until its wings made an angle of 60 degrees with the horizon, and, unable to sustain itself at such a slope, sliding backward into the water.

After much embarrassment the trouble was discovered to be due to the fact that the wings, though originally set at precisely the same position and same angle in the two cases, were irregularly deflected by the upward pressure of the air, so that they no longer had the form which they appeared to possess but a moment before they were upborne by it, and so that a very minute difference, too small to be certainly noted, exaggerated by this pressure, might cause the wind of advance to strike either below or above the wing and to produce the salient difference alluded to. When this was noticed all aerodromes were inverted, and sand was dredged uniformly over the wings until its weight represented that of the machine. The flexure of the wings under these circumstances must be nearly that in free air, and it was found to distort them beyond all anticipation. Here commences another series of trials in which the wings were strengthened in various ways, but in none of which, without incurring a prohibitive weight, was it possible to make them strong enough. Various methods of guying them were tried, and they were rebuilt on different designs,-a slow and expensive process. Finally, it may be said, in anticipation (and largely through the skill of Mr. Reed, the foreman of the work), the wings were rendered strong enough without excessive weight, but a year or more passed in these and other experiments.

In the latter part of 1894 two steel aerodromes had already been built which sustained from 40 to 50 per cent. of their dead-lift weight on the pendulum, and each of which was apparently supplied with much more than sufficient power for horizontal flight (the engine and all the moving parts furnishing over one-horse power at the brake weighed in one of these but 26 ounces); but it may be remarked that the boilers and engines in lifting this per cent. of the weight did so only at the best performance in the shop, and that nothing like this could be counted upon for regular performance in the open. Every experiment with the launch, when the aerodrome descended into the water, not gently, but impelled by the misdirected power of its own engines, resulted at this stage in severe strains and local injury, so that repairing, which was almost rebuilding, constantly went on,-a hard but necessary condition attendant on the necessity of trial in the free air. It was gradually found that it was indispensable to make the frame stronger than had hitherto been done, though the absolute limit of strength consistent with weight seemed to have been already reached, and the year 1895 was chiefly devoted to the labor on the wings and what seemed at first the hopeless task of improving the construction so that it might be stronger without additional weight, when every gramme of weight had already been scrupulously economized. With this went on attempts to carry the effective power of the burners, boilers, and engines further, and modification of the internal arrangement and a general disposition of the parts such that the wings could be placed further forward or backward at pleasure, to more readily meet the conditions necessary for bringing the centre of gravity under the centre of pressure. So little had even now been learned about the system of balancing in the open air that at this late day recourse was again had to rubber models, of a different character, however, from those previously used, for in the latter the rubber was strained, not twisted. These experiments took up an inordinate time, though the flight obtained from the models thus made was somewhat longer and much steadier than that obtained with the Penaud form, and from them a good deal of valuable information was gained as to the number and position of the wings, and as to the effectiveness of different forms and dispositions of them. By the middle of the year a launch took place with a brief flight, where the aerodrome shot down into the water after a little over 50 yards. It was immediately followed by one in which the same aerodrome rose at a considerable incline and fell backward, with scarcely any advance after sustaining itself rather less than ten seconds, and these and subsequent attempts showed that the problem of disposing of the wings so that they would not yield, and of obtaining a proper "balance," was not yet solved.

Briefly it may be said that the year 1895 gave small results for the labor with which it was filled, and that at its close the outlook for further substantial improvement seemed to be almost hopeless, but it was at this time that final success was drawing near. Shortly after its close I became convinced that substantial rigidity had been secured for the wings; that the frame had been made stronger without prohibitive weight, and that a degree of accuracy in the balance had been obtained which had not been hoped for. Still there had been such a long succession of disasters and accidents in the launching that hope was low when success finally came.

I have not spoken here of the aid which I received from others, and particularly from Doctor Carl Barus and Mr. J. E. Watkins, who have been at different times associated with me in the work. Mr. R. L. Reed's mechanical skill has helped me everywhere, and the lightness and efficiency of the engines are in a large part due to Mr. L. C. Maltby.

The Manly Engine

A History of Aeronautics
by E. Charles Vivian

Part IV. - Engine Development - I. , Part III. The Radial Type

The very first successful design of internal combustion aero engine made was that of Charles Manly, who built a five-cylinder radial engine in 1901 for use with Langley's 'aerodrome,' as the latter inventor decided to call what has since become known as the aeroplane. Manly made a number of experiments, and finally decided on radial design, in which the cylinders are so rayed round a central crank-pin that the pistons act successively upon it; by this arrangement a very short and compact engine is obtained, with a minimum of weight, and a regular crankshaft rotation and perfect balance of inertia forces.

When Manly designed his radial engine, high speed internal combustion engines were in their infancy, and the difficulties in construction can be partly realised when the lack of manufacturing methods for this high-class engine work, and the lack of experimental data on the various materials, are taken into account.

During its tests, Manly's engine developed 52.4 brake horsepower at a speed of 950 revolutions per minute, with the remarkably low weight of only 2.4 lbs. per horsepower; this latter was increased to 3.6 lbs. when the engine was completed by the addition of ignition system, radiator, petrol tank, and all accessories, together with the cooling water for the cylinders.

In Manly's engine, the cylinders were of steel, machined outside and inside to 1/16 of an inch thickness; on the side of cylinder, at the top end, the valve chamber was brazed, being machined from a solid forging, The casing which formed the water-jacket was of sheet steel, 1/50 of an inch in thickness, and this also was brazed on the cylinder and to the valve chamber.

Automatic inlet valves were fitted, and the exhaust valves were operated by a cam which had two points, 180 degrees apart; the cam was rotated in the opposite direction to the engine at one-quarter engine speed. Ignition was obtained by using a one-spark coil and vibrator for all cylinders, with a distributor to select the right cylinder for each spark--this was before the days of the high-tension magneto and the almost perfect ignition systems that makers now employ.

The scheme of ignition for this engine was originated by Manly himself, and he also designed the sparking plugs fitted in the tops of the cylinders. Through fear of trouble resulting if the steel pistons worked on the steel cylinders, cast iron liners were introduced in the latter, 1/16 of an inch thick.

The connecting rods of this engine were of virtually the same type as is employed on nearly all modern radial engines. The rod for one cylinder had a bearing along the whole of the crank pin, and its end enclosed the pin; the other four rods had bearings upon the end of the first rod, and did not touch the crank pin.

The accompanying diagram [not avail. Ed.] shows this construction, together with the means employed for securing the ends of the four rods--the collars were placed in position after the rods had been put on. The bearings of these rods did not receive any of the rubbing effect due to the rotation of the crank pin, the rubbing on them being only that of the small angular displacement of the rods during each revolution; thus there was no difficulty experienced with the lubrication.

The Blauer Max - Motoren
Der Sternmotor

Eine weitere dem Umlaufmotor ähnliche Konstruktion ist der sog. Sternmotor. Dem Assistent M. Manly des Flugpioniers Samuel Pierpont Langley gelang Anfang 1900 einen Flugzeugmotor zu entwickeln der seiner Zeit weit voraus war und eine sehr gutes Leistungs - Gewicht - Verhältnis aufwies.

Grundsätzlich handelte es sich hierbei um einen Sternmotor bei dem fünf Zylinder wie ein Stern angeordnet waren. Im Gegensatz zu den Umlaufmotoren hat ein Sternmotor unbewegliche Zylinder mit Kolben, die eine zentrale Kurbelwelle drehen. Manleys Motor war ein echter Verbrennungsmotor. Die Zündkerzen entzündeten das Benzin Luftgemisch in den Zylindern, die sich in einem von Wasser durchflossenen Mantelkühler befanden.

Im weiteren Sinne entsprach dieser Antrieb einem Automobilmotor, unterschied sich von diesem jedoch beträchtlich in seiner Leistung. Während eines 10 Stundentests wurde eine gemessene Leistung von 52,4 PS festgestellt, wenngleich der Motor einschließlich der Zusatzaggregate, dem vollen Tank, der Wasserkühlung und dem Kühler weit unter 90 Kg wog.

1918 hatte der Sternmotor die Umlaufmotoren verdrängt und zur Kühlung wurde mittlerweile der Luftstrom hinter dem Propeller verwendet. Die Kraftübertragung erfolgt von den Zylindern über Pleuelstangen auf einen Kurbelwellenhubzapfen der wiederum die Kurbelwelle antreibt. So war es sogar möglich mit neun Zylinder die Kraft zu übertragen und dies bei einer Motorlänge von der eines Einzylinder - Aggregats.

Außerdem wurde dadurch eine ausgezeichnete Standfestigkeit erzeugt, und die kurze, feste Kurbelwelle wurde wahrscheinlich niemals Drehschwingungen ausgesetzt, von denen in der Anfangszeit der Luftfahrt die Reihen- und V- Motoren geplagt wurden. In den 20er Jahren kam es daher sogar zu Produktionen von zwei versetzten Zylindereihen. Der bekanntesten und erfolgreichste Einsatz eines Sternmotoren wurde sich bei der Atlantiküberquerung von Charles Lindbergh durchgeführt.

Querschnittszeichnung durch einen Sternmotor (5 Zylinder Sternmotor von Charles Manly - hier wird nur der obere vertikale Zylinder gezeigt).


1. Zylinder; 2. Zündkerze; 3. Kolben; 4. Pleuelstange; 5. hohler Kurbelwellenhubzapfen, 6. runde Antriebswelle für Steuer- und Backbordpropeller, 7. Stößelstange des Ausströmventils; 8. Ein- und Auslaßventil

Further Reading

Samuel Pierpont Langley

The second individual to make an impact during this decade was Samuel Pierpont Langley. Although his attempts at powered flight were unsuccessful, he highlighted some of the issues relating to flight and the necessity of using a sound research methodology....more

The Langley Airship

Prof. Langley has issued the following statement:

To the Press:

The present experiments being made in mechanical flight have been carried on partly with funds provided by the Board of Ordnance and Fortifications, and partly from private sources, and from a special endowment of the Smithsonian Institution. The experiments are carried on with the approval of the board of regents of the Smithsonian Institution. The public's interest in them may lead to an unfounded expectation as to their immediate results without an explanation, which is here briefly given....more

Langley's Aerodrome Experiments
Scientific American, 89, August 22, 1903

Prof. Langley's 12-foot aerodrome was tested on August 8, with results considered decidedly encouraging by its inventor. The model flew a distance of 600 yards and then sank in 22 feet of water. When it was finally recovered, all that was left was a tangled wreck of twisted wires. The time consumed in flight was not more than 45 seconds....more

The Failure of Langley's Aerodrome
Scientific American, 89, October 17, 1903

Those who have the interests of aerial navigation at heart will regret the failure of Prof Langley's last experiment, not so much because the aerodrome refused to fly, but because of the adverse newspaper comment which the trial has prompted no scientist was ever absolutely successful in every experiment which he has undertaken, least of all is success to be expected in so precarious an undertaking as that of testing the capabilities of a new flying machine....more

Langley's Folly

The following story is excerpted from the book, Failing Forward: Turning Mistakes Into Stepping Stones For Success, by John C. Maxwell. Copyright 2000. Thomas Nelson, Inc., publishers.

Just about everyone has heard of the Wright brothers, the bicycle mechanics who pioneered manned motorized flight in the first part of the twentieth century. The circumstances surrounding Orville and Wilbur Wright's first flight on December 17, 1903, make an interesting story. But what you may not know is that prior to that day, the Wrights, unknowns with no university education, were not the leaders in aviation. They were obscure at best, and another man was expected to put the first airplane in the air. His name was Dr. Samuel P. Langley....more

Langley's Feat - and Folly

The Smithsonian Secretary assembled a devoted team, a remarkable engine and a plane that wouldn't fly It stands unobtrusively in the Early Flight gallery on the ground floor of the National Air and Space Museum (NASM). Look below and just beyond the 1894 glider flown by aviation pioneer Otto Lilienthal, and there it is, a primitive radial aircraft engine not quite four feet in diameter, modestly displayed. But don't dismiss it. This small piece of machinery has a tale to tell....more

Samuel Pierpont Langley

Some time during [his] busy years of solar research at Allegheny Observatory [Langley's] thoughts turned actively to the possibility of man flying through the air. This was, of course, a general topic of the times, much like space flight is today. It was a dream that Langley had nurtured since boyhood when he would lie in the meadow watching the birds in flight. Langley theorized that a flying bird, weighing nearly a thousand times as much as the air it displaced, had to be sufficient evidence that heavier-than-air flight could not be impossible....more

A History of Aeronautics : Part X. Samuel Pierpont Langley
by E. Charles Vivian

Samuel Pierpont Langley was an old man when he began the study of aeronautics, or, as he himself might have expressed it, the study of aerodromics, since he persisted in calling the series of machines he built 'Aerodromes,'......a great race between Langley, aided by Charles Manly, and Wilbur and Orville Wright, and only the persistent ill-luck which dogged Langley from the start to the finish of his experiments gave victory to his rivals....more

Samuel Pierpont Langley

Samuel Pierpont Langley, born on August 22, 1834 in Roxbury, Massachusetts...Langley's interest in flight came in 1886, at the age of 52, when he attended a lecture of the American Association for the Advancement of Science. He eagerly read the literature on the subject and convinced the Board of Trustees of the Allegheny Observatory to support his study into the possibility of heavier-than-air flight....more

Samuel Pierpont Langley

Samuel Pierpont Langley was a significant pioneer in the early days of aeronautical research. Born in 1834, he spent much of his early life pursuing an interest in astronomy and eventually became a professor of mathematics and physics. As director of the Allegheny Observatory in Pittsburgh, he attended the American Association of the Advancement of Science in 1886 where he became fascinated by a presentation on the flight of birds....more

Langley's Steam-Powered Flying Machines

Aerodrome No. 5 sits in the Smithsonian Institution's shop following two successful flights on May 6, 1896. (National Air And Space Museum)

More than 100 years ago, Samuel Langley's team of specialists from the Smithsonian Institution proved to a small group of astonished observers that powered flight was possible. But they still had to prove that their Aerodrome could safely carry a man into the sky.

By C. David Gierke

Samuel Pierpont Langley paced impatiently on the deck of a houseboat on May 6, 1896. His friend and fellow scientist, Alexander Graham Bell, stood nearby. The previous day, they had taken the train 41 miles from Washington, D.C., to the village of Quantico, Virginia. In a shallow, remote cove on the Potomac River, they watched nervously while workmen made final adjustments to the sixth in a series of experimental steam-powered flying models that Langley called "Aerodromes." Finally, at 1:10 p.m., with the model's propellers turning at maximum speed, Langley gave the signal to launch. When the launch lever was pulled, powerful springs catapulted the large model along its 20-foot launching rail. Takeoff!...more

Icarus on the Mall

At the Smithsonian, he [Langley Ed.] quickly established himself as the august director of projects and studies....but he found time to pursue such pet projects as "lighter than air" machines and to maintain control of the Allegheny Observatory. There, in the summer of 1887, he helped design a "whirling table," two 30-foot armatures on a revolving vertical shaft capable of speeds of 70 miles an hour. With it, he hoped to reproduce mechanically the aerodynamics of flight....more

Samuel Pierpont Langley

Samuel Pierpont Langley (1834 - 1906) is often used as a contrast to the Wrights. Unlike the two brothers, Langley was highly-educated and had more than ample funding in support of his efforts to develop an airplane. His stature at Secretary of the Smithsonian Institution lent great credibility to his efforts to build an airplane, as did his success with the unmanned aerodromes.

In particular, his Aerodrome No. 6 flew 4,200 feet at about 30 mph on November 28, 1896. This unmanned tandem-wing craft employed a lightweight steam engine for propulsion. The wings were set at a distinct dihedral angle so that the craft was dynamically stable, capable of righting itself when disturbed by a sideways breeze. There was no method of steering this craft, nor would it have been easy to add any means to control the direction the craft flew....more

Samuel Langley: (1834-1906) : from failure to posterity
by Philippe Ballarini, translation: Michel Léveillard

Before consecrating his life to aviation research, Samuel Pierpont Langley (born in 1834), had distinguished himself with his work on physic and astronomy, and by publishing a book concerning Experiments in aerodynamics.

This eminent personality who was the secretary of the renowned Smithsonian Institute in Washington, could not ignore the new wave of enthusiasm to give wings to the ending ninetieth century. Closely studying the work of Clément Ader and Otto Lilienthal, he began building flying scaled models, propelled by rubber band motors, and having the particularity of a double set of wings mounted in the tandem configuration....more

Samuel Langley

Samuel Langley, born in 1834 is often compared with the Wright brothers because they were aiming for the same goal at around the same time. However, Langley never really achieved the fame that the Wright Brothers had. Although Langley, unlike the Wrights was well educated, had ample funding, and had great support....more

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