Wright Brothers

Toward flight

First flight, December 17, 1903.In 1899 Wilbur put wing-warping to the test by building and flying a five-foot box kite in the approximate shape of a biplane. When the wings were warped, or twisted, one end would receive more lift and rise, which would start a turn in the direction of the lower end. To allow warping, the front and rear posts between the wings of the kite (and later, manned gliders) were unbraced. Warping was controlled by wires running through the structure, which led to sticks held by the kite flyer, who could pull one or the other to twist the wings and make the kite bank left or right. It worked.

In 1900 the brothers went to Kitty Hawk, North Carolina to continue their aeronautical work — choosing Kitty Hawk (specifically, a sand dune called Kill Devil Hill) on the advice of a Weather Bureau meteorologist because of its strong and steady winds, and because its remote location afforded the brothers privacy from prying eyes in the highly competitive race to invent a successful heavier-than-air flying machine.


The gliders
For more information, see Wright Glider

They based the design of their first full-size glider on the Chanute-Herring "double-decker," a hang glider which flew well in experiments in 1896 near Chicago. The uprights between the wings of the Chanute and Wright gliders were braced by wires in a modified "Pratt truss," which Chanute, an engineer, had adapted from his bridge-building experience. The general appearance of these gliders was similar to the biplanes that would usher in the era of flight in the next few decades.

The brothers flew the glider only a few days in the summer of 1900 at Kitty Hawk. In early tests Wilbur was aboard the glider while it flew as a kite not far above the ground with men below holding tether ropes. Many of the kite tests were unpiloted with sandbags or chains (and even a local boy) as onboard ballast. The glider was also tested unmanned while suspended from a small homemade tower. Wilbur (and possibly Orville) made free glides on only one day. Although lift was less than expected, the brothers were encouraged since the front elevator worked well and they had no accidents. Because they did so little untethered gliding, they were not able to give wing-warping a true test.

The pilot lay flat on the lower wing, as planned, to reduce aerodynamic drag. As a glide ended, the pilot was supposed to lower himself to a vertical position through an opening in the wing and land on his feet with his arms wrapped over the framework. Within a few glides, however, they discovered the pilot could remain prone on the wing, headfirst, without undue danger when landing. They made all their flights in that position for the next five years.

They built the 1901 glider with a much larger wing area, hoping to improve lift. This glider, however, delivered two major disappointments. It produced much less lift than calculated and sometimes failed to respond properly to wing-warping, turning opposite the direction intended. On the trip home after their second season, Wilbur, stung with disappointment, remarked to Orville that man would fly, but not in their lifetimes. In the fall of 1901 they renewed their efforts and conducted systematic wind tunnel experiments. In only a few weeks they re-defined fundamental knowledge of lift, drag, wing shapes and airfoil curves. With a greater "aspect ratio"--longer wingspan and shorter chord (front-to-back wing dimension)--the 1902 glider that emerged from this research looked much more like the modern idea of an aircraft than their previous machines, possessing a notably more graceful appearance. The airfoil also had a flatter camber--the ratio of the wing's maximum thickness to its chord. The 1901 wings had been significantly thicker, a feature copied from Lilienthal. With their own wind tunnel data in hand, they were no longer copying anyone else's designs.


Wilbur Wright pilots the 1902 glider near Kitty Hawk, Oct 10, 1902. The single rear rudder shown is steerable; it replaced the original fixed double rudder.With characteristic caution, the brothers first flew the 1902 glider as a large unmanned kite, as they had done with their two previous versions. Rewarding their wind tunnel work, the glider produced the expected lift. It also had a new structural feature: a fixed, rear vertical rudder, which the brothers hoped would eliminate the problem of turns that went contrary to warping control. They understood that warping to increase lift at one end of the wing in order to raise it and bank into a turn also increased drag on that end, slowing it, which sometimes made the aircraft turn in the wrong direction.

The improved wing design, generating greater lift, enabled consistently longer glides, but the problem of turns was only partly solved. The glider did not turn opposite its warping control anymore, but sometimes when the wind tilted the glider to one side, the craft failed to respond to wing-warping and continued to slide toward the lower wing, which hit the ground. Orville suggested to Wilbur that the rear rudder be moveable, under control of the pilot, to overcome the problem. Turning the rudder would reduce pressure on one side of it--pressure that could force the glider to continue an unwanted turn--and increase pressure on the other side, in the direction of a desired turn. Through logic and experiments in the air, the brothers discovered the rudder should be turned toward the wingtip that was warped to receive less lift (the lower wing when making a turn, the higher wing when leveling off from a turn or a wind disturbance).

To simplify matters, they connected the rudder to the warping controls so a single movement (of their hips in the warping "cradle") simultaneously controlled wing warping and rudder deflection.


Wilbur making turn Oct. 24, 1902.With this method they achieved true control in turns and made about a thousand glides, some lasting nearly 30 seconds and exceeding 600 feet distance--the best results anyone had ever achieved. Thus, did three axis-control evolve: wing-warping for roll (lateral motion), forward elevator for pitch (up and down) and rear rudder for yaw (side to side). On March 23, 1903 they applied for a patent for their novel technique of flight control.





USPS stamp depicting the "Flight."[edit]
Adding power
In 1903, they built the Wright Flyer - later the Flyer I (today popularly known as the Kitty Hawk) - carved their own propellers, and had a purpose-built engine made by Charlie Taylor in their bicycle shop in Dayton, Ohio. The propellers had an 80% efficiency rate. The engine was superior to manufactured ones, having a high enough power-to-weight ratio to use on an aeroplane. The chains used to drive the propellers, though resembling those of bicycles, were heavy-duty hardware from a manufacturer of automobile chain-drives. While the early engines used by the Wright brothers are thought to no longer exist, a later example, serial number 17 from circa 1910, is on display at the New England Air Museum in Connecticut.


Wright engine serial # 17, circa 1910By autumn 1903 the Wright brothers were skilled glider pilots. Before attempting their first powered flights of the year, they made many glides in their 1902 machine, surpassing their own records for duration and distance.

Then on December 17, 1903, in a frigid wind gusting to 27 miles an hour, the Wrights took to the air in their powered Flyer, both of them twice. The first flight, by Orville, of 39 meters (120 feet) in 12 seconds, was recorded in a famous photograph. In the fourth flight of the day, the one most fully controlled, Wilbur flew 279 meters (852 ft) in 59 seconds. Their altitude on the four flights was about ten feet above the ground. [1].

The flights were witnessed by 4 lifeguards and a boy from the village, making it arguably the first public flight. A local newspaper reported the event, inaccurately. Only one other newspaper, the Cincinnati Enquirer, printed the story the next day.

The Flyer I cost less than a thousand dollars to construct. It had a wingspan of 40 feet (12 m), weighed 750 pounds (340 kg), and sported a 12 hp (9 kW), 170 pound (77 kg) engine. After the fourth flight of December 17th, a strong wind overturned the parked Flyer and wrecked it; the aircraft never flew again. The brothers shipped the pieces home, and years later Orville restored the Flyer, lending it to several museums in the U.S., then to a British museum (see Smithsonian dispute below), before it was finally installed in the Smithsonian Institution in Washington, D.C. in 1948.


Milestones of the flight
The Wright Flyer flight was notable in that 1) the aircraft moved under its own power, unassisted by gravity; 2) the flight was prolonged through direct, conscious, and active manipulation of control surfaces, instead of merely making an uncontrolled "hop"; 3) the flight has been reproduced experimentally using a painstakingly recreated replica of the original aircraft. Also notable is the fact that the Wright brothers accurately described several principles of flight (including aerodynamics and propeller design) that previous pioneers had either described inaccurately or not at all.

It is important to note that several replicas of the original Wright Flyer have been modified by using modern aerodynamic knowledge to improve their flight characteristics. However, at least one replica exists that has made flights without being so modified. The Wright Experience, through painstaking research of original documents, photographs, and artifacts from the original Flyer (conducted much like an archaeological expedition), managed to accurately and precisely recreate it. Their stated purpose was to build an exact replica of the original aircraft, whether or not it would actually fly. As it turned out, the aircraft did indeed make several successful flights.


Trouble establishing legitimacy
The Wrights established a flying field at Huffman Prairie near Dayton and continued work in 1904, building the Flyer II. In May they invited reporters to their first flight attempt of the year, but engine troubles prevented any flying, and they could manage only a very short hop a few days later with fewer reporters present. Some scholars of the Wrights speculate the brothers may have intentionally failed to fly in order to disinterest reporters in their experiments.[13] Whether that is true is not known, but their poor showing did result in the local newspapers virtually ignoring them for the next year and a half.


Orville in flight over Huffman Prairie, approximately 1,760 feet in 40 1/5 seconds, Nov. 16, 1904.Lighter winds and lower air density than in Kitty Hawk (due to Ohio's higher altitude and higher temperatures) made takeoffs very difficult, and they had to use a much longer starting rail, stretching to hundreds of feet. During the spring and summer they suffered many hard landings, real crackups, repeated Flyer damage, and bodily bumps and bruises to show for it. In August, making an unassisted takeoff, they finally flew farther than their longest powered flight at Kitty Hawk. Then they decided to use a catapult to make takeoffs easier and tried it for the first time on September 7th. On September 20th, 1904 Wilbur flew a complete circle in about a minute and a half—the first in history by a heavier-than-air flying machine. By the end of the year, the brothers had made 105 flights over the rather soggy 85 acre pasture, which, remarkably, is virtually unchanged today from its original condition and is now part of Dayton Aviation Heritage National Historical Park, adjacent to Wright-Patterson Air Force Base.

In 1905, they built an improved aeroplane, the Flyer III, and by October 5, Wilbur set a record of over 39 minutes in the air and 24½ miles (39 km) circling Huffman Prairie, landing only when his fuel ran out. The flight was seen by a number of people, including several invited friends and their father. Reporters showed up the next day (their first appearance at the field since May the previous year), but the brothers declined to fly. The only photos of the flights of 1904-05 were taken by the brothers.

In 1904 Ohio beekeeping businessman Amos Root, a technology enthusiast, saw a few flights including the first circle. Articles he wrote for his beekeeping magazine were the only published eyewitness reports of the Huffman Prairie flights, except for the unimpressive early hop local newsmen saw. Root offered a report to Scientific American magazine, but the editor turned it down. As a result, the news was not widely known outside of Ohio, and was often met with skepticism. The Paris edition of the Herald Tribune headlined a 1906 article on the Wrights "FLYERS OR LIARS?"

In years to come, Dayton newspapers would proudly celebrate the hometown Wright brothers as national heroes, but the local newsmen's ability to overlook one of the biggest stories in human history as it was happening a few miles from their doorstep stands as a unique chapter in the annals of American journalism.

The Wright brothers were, in fact, complicit in the lack of attention they received. Wary of the competition stealing their plans, after 1905 they refused to make public demonstrations or take part in air shows before signing firm contracts with the military. They attempted to sign contracts with the United States Army, the French Army, the British Army, and the German Army, but all refused because the Wrights insisted on a signed contract before giving a flight demonstration. Thus, doubted or scorned by the press, the Wright brothers continued their work in semi-obscurity, while other aviation pioneers like Brazilian Alberto Santos-Dumont and American Glenn Curtiss were occupying the limelight.

The Wright brothers made no flights at all in 1906 and 1907. After finally signing contracts with a French company and the U.S. government, they went back to Kitty Hawk in May 1908 with the 1905 Flyer, modified with seats for pilot and passenger, and began practicing for their all-important demonstration flights. Their contracts required them to be able to carry a passenger. After tests with sandbags in the passenger seat, Charlie Furnas, a helper from Dayton, became the first fixed-wing aircraft passenger on a few short flights May 14. For safety and as a promise to their father, Wilbur and Orville did not fly together.


The patent
Their 1903 patent application, which they wrote themselves, was rejected. In early 1904 they hired Ohio patent attorney Henry Toulmin, and on May 22, 1906 they were granted patent #821,393 for a "Flying Machine". Significantly, this patent illustrated a non-powered flying machine. The patent's importance lies in its claim of a new and useful method of controlling a flying machine, powered or not. The technique of wing-warping is described, but the patent explicitly states that wing-warping need not be the only method that could be employed to vary the angle presented to the air by the outer portions of a machine's wings. The concept of varying the angle near the wingtips, by whatever means, is central to the patent. The broad protection intended by this language was important in the patent infringement lawsuits the Wrights brought and won against Glenn Curtiss and other early aviators who adopted ailerons while the Wrights continued to use wing-warping (see Patent War section below). The patent also describes the innovative steerable rear vertical rudder and its vitally important use in combination with wing-warping to overcome the problem of "skidding" (adverse yaw) when turning the aeroplane. Finally, the patent describes the forward elevator, used for ascending and descending.


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