The Wright Flyer (also known as the Kitty Hawk, Flyer I or the 1903 Flyer) made the first sustained flight by a manned heavier-than-air powered and controlled aircraft on December 17, 1903. Invented and flown by brothers Orville and Wilbur Wright, it marked the beginning of the pioneer era of aviation.
The aircraft is a single-place biplane design with anhedral (drooping) wings, front double elevator (a canard) and rear double rudder. It used a 12 horsepower (9 kilowatts) gasoline engine powering two pusher propellers. Employing "wing warping", it was relatively unstable and very difficult to fly.
The Wright brothers flew it four times in a location now part of the town of Kill Devil Hills, about 4 miles (6 kilometers) south of Kitty Hawk, North Carolina. The airplane flew 852 ft (260 m) on its fourth and final flight, but was damaged on landing, and wrecked minutes later when powerful gusts blew it over.
The brothers shipped the wreckage back to Dayton, and the aircraft never flew again. Orville later restored it and displayed it on several occasions. The Flyer joined the Smithsonian Institution's collection of historic aircraft in 1948 after the end of a long and bitter dispute between Orville and the Institution over its refusal to recognize the Flyer as the first successful airplane. Today, it is on display in a place of honor in the National Air and Space Museum in Washington, D.C.
The Flyer was based on the Wrights' experience testing gliders at Kitty Hawk between 1900 and 1902. Their last glider, the 1902 Glider, led directly to the design of the Wright Flyer.
The Wrights built the aircraft in 1903 using spruce for straight members of the airframe (such as wing spars) and ash wood for curved components (wing ribs). The wings were designed with a 1-in-20 camber. The fabric for the wing was 100% cotton muslin called "Pride of the West", a type used for women's underwear. It had a warp of 107 threads per inch, a weft of 102, and a total thread count of 209.
Since they could not find a suitable automobile engine for the task, they commissioned their employee Charlie Taylor to build a new design from scratch, a lightweight 12-horsepower (9-kilowatt) gasoline engine, weighing 180 pounds (82 kg), with a 1-US-gallon (3.8 L; 0.83 imp gal) fuel tank. A sprocket chain drive, borrowing from bicycle technology, powered the twin propellers, which were also made by hand. In order to avoid the risk of torque effects from affecting the aircraft handling, one drive chain was crossed over so that the propellers rotated in opposite directions.
"They figured on four cylinders and estimated the bore and stroke at four inches. It took me six weeks to make that engine. The completed engine weighed 180 pounds and developed 12 horsepower at 1025 revolutions per minute...The body of the first engine was of cast aluminum, and was bored out on the lathe for independent cylinders. The pistons were cast iron, and these were turned down and grooved for piston rings. The rings were cast iron, too. A one-gallon fuel tank was suspended from a wing strut, and the gasoline fed by gravity down a tube to the engine. The fuel valve was an ordinary gaslight petcock. There was no carburetor as we know it today. The fuel was fed into a shallow chamber in the manifold. No spark plug. The spark was made by opening and closing of two contact points inside the combustion chamber. Dry batteries were used for starting the engine and then we switched onto a magneto bought from the Dayton Electric Company. There was no battery on the plane. Several lengths of speaking tube...were used in the radiator. We blocked-tested the motor before crating it for shipment to Kitty Hawk."
The 8.5 foot (2.6 m) long propellers were based on airfoil number 9 from their wind tunnel data, which provided the best "gliding angle" for different angles of attack. The propellers were connected to the engine by chains from the Indianapolis Chain Company, with a sprocket gear reduction of 23-to-8. Wilbur had calculated that slower turning blades generated greater thrust, and two of them were better than a single blade turning faster. Made from three laminations of spruce, the tips were covered with duck canvas, and the entire propeller painted with aluminum paint.
On November 5, 1903, the brothers tested their engine on the Wright Flyer at Kitty Hawk, but before they could tune the engine, the propeller hubs came loose. The drive shafts were sent back to Dayton for repair, and returned on 20 November. A hairline crack was discovered in one of the propeller shafts. Orville returned to Dayton on 30 November to make new spring steel shafts. On December 12, the brothers installed the new shafts on the Wright Flyer and tested it on their 60-foot (18 m) launching rail system that included a wheeled launching dolly. According to Orville:
"We had designed our propellers to give 90 pounds (41 kg) thrust at a speed of 330 rev. per minute (about 950 of engine), which we had figured would be the required amount for the machine weighing 630 pounds (290 kg)."
In practice tests, they were able to achieve a propeller rpm of 351, with a thrust of 132 pounds (60 kg), more than enough for their 700-pound (320 kg) flyer.
The Wright Flyer was a canard biplane configuration, with a wingspan of 40 feet 4 inches (12.29 m), a camber of 1-20, a wing area of 510 square feet (47 m2), and a length of 21 feet 1 inch (6.43 m). The right wing was 4 inches (10 cm) longer because the engine was 30 to 40 pounds (14 to 18 kg) heavier than Orville or Wilbur. Unoccupied, the machine weighed 605 pounds (274 kg). As with the gliders, the pilot flew lying on his stomach on the lower wing with his head toward the front of the craft in an effort to reduce drag. The pilot was left of center while the engine was right of center. He steered by moving a hip cradle in the direction he wished to fly. The cradle pulled wires to warp the wings, and simultaneously turn the rudder, for coordinated flight. The pilot operated the elevator lever with his left hand, while holding a strut with his right. The Wright Flyer's "runway" was a 60-foot (18 m) track of 2x4s, which the brothers nicknamed the "Junction Railroad". The Wright Flyer skids rested on a launching dolly, consisting of a 6-foot (1.8 m) plank, with a wheeled wooden section. The two tandem ball bearing wheels were made from bicycle hubs. A restraining wire held the plane back, while the engine was running and the propellers turning, until the pilot was ready to be released.
The Wright Flyer had three instruments on board. A Veeder engine revolution recorder measured the number of propeller turns. A stopwatch recorded the flight time, and a Richard hand anemometer, attached to the front center strut, recorded the distance covered in meters.
Upon returning to Kitty Hawk in 1903, the Wrights completed assembly of the Flyer while practicing on the 1902 Glider from the previous season. On December 14, 1903, they felt ready for their first attempt at powered flight. With the help of men from the nearby government life-saving station, the Wrights moved the Flyer and its launching rail to the incline of a nearby sand dune, Big Kill Devil Hill, intending to make a gravity-assisted takeoff. The brothers tossed a coin to decide who would get the first chance at piloting, and Wilbur won. The airplane left the rail, but Wilbur pulled up too sharply, stalled, and came down after covering 105 ft (32 m) in 31⁄2 seconds, sustaining little damage.
Repairs after the abortive first flight took three days. When they were ready again on December 17, the wind was averaging more than 20 mph (32 km/h), so the brothers laid the launching rail pointed into the wind on level ground near their camp. This time the wind, instead of an inclined launch, provided the necessary airspeed for takeoff. Because Wilbur already had the first chance, Orville took his turn at the controls. His flight, captured in a famous photograph, lasted 12 seconds for a total distance of 120 feet (37 m) – shorter than the wingspan of a Boeing 747. The brothers made three more flights, taking turns. The second and third flights were 175 and 200 feet (53 and 61 m) in 12 and 15 seconds respectively. The fourth and last flight, by Wilbur, took 59 seconds to cover 852 feet (260 m) over the ground, moving through approximately a half mile (800 m) of flowing air.