At 10:35 a.m., on December 17, 1903, Wilbur and Orville Wright made history in Kitty Hawk, North Carolina, when they made the first powered, controlled flight of a heavier-than-air flying machine, a craft they designed and built, simply called the Flyer. The airplane had been invented.
The flight lasted only 12 seconds, but it was a true flight nevertheless. The brothers would make three more flights that day, the longest covering 852 feet in 59 seconds.
These history-making 1903 flights weren’t the Wrights’ first time at Kitty Hawk. The brothers had begun visiting a few years earlier, starting in 1900, to test gliders and use the data they gathered in their tests to refine their designs and eventually build their 1903 Flyer.
Why Kitty Hawk?
For their tests, the Wrights needed a place with wide-open spaces and strong, steady winds. They wrote to the U.S. Weather Bureau in Washington, D.C., to find suitable locations. Among the paces that seemed promising was Kitty Hawk, North Carolina, a small fishing village on an isolated strip of beach on the mid-Atlantic coast. Later, Orville would describe Kitty Hawk as “like the Sahara, or what I imagine the Sahara to be.”
Beyond the favorable conditions for gliding, the welcoming response to a letter Wilbur wrote to the local weather station settled the matter. William Tate, considered the best educated resident in the modest little fishing village of Kitty Hawk, enthusiastically recommended it as a fine place to conduct the experiments Wilbur described, and offered to help in any way he could. Tate replied on August 18, 1900, “If you decide to try your machine here & come I will take pleasure in doing all I can for your convenience & success & pleasure, & I assure you you will find a hospitable people when you come among us.”
The First Tests: The 1900 Glider
The Wright brothers began developing their design ideas for a flying machine with a series of gliders before attempting to build a powered airplane.
Their 1900 glider incorporated the wire-braced biplane structure and wing-warping control system they developed with their earlier 1899 kite. Lying on the lower wing, the pilot controlled the gilder laterally by operating a crossbar mounted behind him with his feet. In addition, the horizontal had levers in front of him flexed the forward elevator up and down, controlling pitch.
The glider generated less lift than the brothers’ had predicted. However, the control system—wing warping for lateral (roll) control and the forward elevator for pitch control—worked beautifully. While the Wrights managed only two minutes of free gliding that first visit to Kitty Hawk, those precious seconds in the air proved their innovative control ideas were sound.
Improving the Glider: The 1901 Glider
The poor lift performance of the 1900 glider made the Wright brothers question, but not abandon, the aerodynamic data and equations from others they had relied on. To increase lift on their next glider, they simply increased the size of the wings and the curvature of the airfoil (wing cross-section).
The brothers returned to Kitty Hawk in 1901 to test their improved glider design. The results were discouraging. Although they made more and longer glides than in the previous year, the new glider performed worse than the 1900 glider. It still suffered from lack of lift—only one third the amount predicted—and now had control problems. The elevator was now overly sensitive and erratic. When they warped the wings, the glider initially turned in the intended direction, but then suddenly reversed itself.
The brothers suspected the large increase they had made to the airfoil curvature was causing the problems. They re-rigged the wings to have a shallower curvature and were partially successful. The responsive pitch control returned, but the lift remained poor.
Back in Dayton
The gliders the Wright brothers had designed and tested were based on accepted equations for lift and drag. They also used Otto Lilienthal’s aerodynamic data, and Smeaton’s coefficient for air density. When the gliders at Kitty Hawk failed to produce the lift that calculations predicted, Wilbur and Orville decided to check Lilienthal’s data and Smeaton’s coefficient.
First, they adapted a bicycle to create a device to measure the lift of an airfoil. Using their bicycle-device, the brothers concluded that the wing of their glider needed to be at an angle to the wind more than three times greater than what Lilienthal’s data predicted. Their crude device confirmed their suspicions that either Lilienthal’s data or Smeaton’s coefficient—or both—were wrong. They would need a more precise apparatus, a wind tunnel, for further tests to be sure.
So build a wind tunnel they did. Actually, they built two—a smaller one for initial tests, and a larger one for extensive research. Using the wind tunnel, they tested dozens of wing shapes, including the one Lilienthal used to derive his aerodynamic data, and selected the most efficient wing shape for their aircraft. They also derived a more accurate value for Smeaton’s coefficient. Since the 1700s, the value of 0.005 had been used for the coefficient. The Wright brothers calculated the new average value of 0.0033.
Returning to Kitty Hawk: 1902 Glider
Armed with this data, they were ready to return to Kitty Hawk. The brothers decided to build one more glider, rather than immediately testing a powered flying machine. They couldn’t be sure that the data obtained in their wind tunnel from tiny model wings would translate to a full-size aircraft.
Compared to their earlier gliders, the 1902 glider had a much thinner airfoil and longer and narrower wings, which their wind tunnel tests had shown to be more efficient. To improve lateral control, they added a fixed, double-surface, vertical rudder to the rear of the glider. They retained the reliable forward elevator for pitch control, but changed the shape.
The improvement in performance from all these changes was dramatic. When kiting the glider, the Wrights’ usual first step, the improved lift performance was evident—the glider could sustain nearly level flight—something the other gliders had not achieved.
When flying the glider, the new fixed vertical rudder seemed to control some of the problems they experienced with the 1901 glider. However, sometimes the reversal of the glider’s direction in a turn was even more sudden and violent. The Wrights called these episodes “well digging,” referring to the small crater left in the sand when the glider uncontrollably hit the ground. To solve this the brothers made adjustments “in the field” at Kitty Hawk. The Wrights made the rudder moveable, so it could be coordinated with the wing-warping. They also made it a single-surface rudder.
It worked! The Wrights had created the first fully controllable aircraft with control over pitch (climb and descent), roll (banking the wings), and yaw (nose side to side). The three-axis control system was their single most important design breakthrough. “Our new machine is a very great improvement over anything … anyone has built,” Wilbur explained on October 2, 1902, “Everything is so much more satisfactory that we now believe that they flying problem is really nearing its solution.”
During September and October, the brothers made between 700 and 1,000 glides, getting extensive practice in the air. “We now hold all records,” Orville wrote home.
Inventing the Airplane
Buoyed by this success, Orville and Wilbur returned to Dayton and looked at the final hurdles to inventing the airplane, including refining their design and creating a propulsion system to enable powered flight.
The Wright engine was a bit crude, even by standards of the day—but was revolutionary in one sense. The crankcase was made of aluminum, the first time this lightweight material was used in airplane construction. Charlie Taylor, a mechanic who had been working in the Wrights’ bicycle shop, helped design the engine and did virtually all the machine work to build it.
One of the most innovative aspects of the 1903 Flyer was its propellers. The Wrights decided to treat the propeller as if it were a rotary wing.
The controls on the Wright Flyer were similar to those on the 1902 glider.
Making History in Kitty Hawk
The Wright brothers returned to Kitty Hawk in September 1903. This time things were different, they were no longer conducting experiments. They were going to fly an airplane.
The Flyer was too big for the Wrights to assemble in their shop in Dayton and run the engine with the propellers, so the first several weeks in North Carolina were spent putting together the airplane and trouble-shooting the propulsion system.
The transmission system in particular gave them trouble. The two counter-rotating propellers were connected to the centrally mounted engine via a set of chains and sprockets. The jerking motion of the chains caused the sprockets to loosen and damage the propeller shafts—Orville returned to Dayton to make new shafts and arrived back in Kitty Hawk on December 11. By then harsh winter weather was closing in.
The Flyer ended up 125 pounds heavier than the Wrights initially estimated. Fortunately, their propellers provided 50% more thrust than expected, which the brothers hoped would compensate for the extra weight.
Another innovation was needed. The powered airplane weighed too much to be hand launched like the gliders had been. The brothers built a 60-foot wooden launching rail. The airplane rode down the rail on a small wheeled dolly for take-off.
The Wright Flyer was ready to fly, but who would fly it? They decided by a coin toss: Wilbur would fly first.
Forty feet down the launching rail, the Flyer lurched up, stalled, and smashed into the sand. The forward elevator was slightly damaged, requiring repair, but the brothers were undeterred. The Flyer was airborne for 3.5 seconds, but the power of the engine and the responsiveness of the controls bolstered Wilbur’s confidence. He wrote home “There is now no question of success.”
Three days later, the damage was repaired, and the brothers were ready to try again. It was freezing outside with a 27-mph wind. This time Orville took the controls. Liftoff! The Flyer darted up and down as it sailed slowly over the sand—a result of the overly sensitive elevator control—at last coming to rest with a thud 120 feet from where it took off. It was a short flight—only 12 seconds—but it was a true flight nevertheless. A human had flown.
The Wright brothers made three more flights that day, each taking a turn to fly. On the final flight, with Wilbur at the controls, he steadied the airplane for an impressive 852-foot trip in 59 seconds, definitively demonstrating that the Wright Flyer was capable of sustained, controlled flight. The airplane had been invented!
