Wright Bros Flyer I
Powerfully encouraged by the 1902 flights, the Wright brothers began immediately to construct a four-cylinder gasoline motor (its design based on a smaller unit they had already built to drive their wind tunnel) to power a still bigger aircraft to be tested during their next vacation, in the fall and winter of 1903. For the first time, they were confronted with the need to design screw propellers.
The airframe in which the first flights were made was an equal-span, unstaggered, biplane of 40ft 4in span and 510 sq ft wing area, with front biplane-elevator and aft twin-rudders, a half-gallon fuel tank and a cradle for a single, prone, pilot on the lower wing. Its empty weight was "a few pounds over 600 lb". Loaded for the flights it weighed "a little over 745 lb” for a wing-loading of 1.46 lb per sq ft and a power-loading of 74.5 lb per hp. It was the fourth Wright-built biplane (and the first to be powered) since their first kite of August 1899, and it had deliberately been made unstable "to improve control".
The power-plant was, like all the rest, designed and built by the Wrights in their bicycle shop at Dayton. It was a 3.3 litre (201 cu in) four-cylinder inline, horizontal water-cooled four-stroke, with low-tension magneto ignition. Running on "cooking" gasoline it was capable of 13 measured brake-horse-power at 1,750 r.p.m. and it achieved 132 lb of static thrust by driving two, 8ft 6in diameter opposite-rotating pusher propellers (likewise Wright designed and built) mounted on shafts between the mainplanes and driven through cycle-chains at a gearing of 23 to 8. Flight was sustained at 1,030 r.p.m. which yielded ten horsepower to the shafts.
Wright Flyer I
The new machine (which had cost them almost $1,000) was transported to their Carolina campsite in September 1903; while making preparations to test it, they continued to practice piloting with their 1902 glider. They encountered problems with the power transmission to the twin counter-rotating propellers of their new machine and it wasn't until December 14 that they were ready to try a takeoff from their monorail "runway."
Success came three days later when four flights - the last the best, covering 852 feet in 59 seconds - were made. The first flight on 17th December 1903 Orville covered only 120 feet, his speed was only 31 m.p.h. and the flight lasted just 12 seconds. The machine followed an undulating flight path just above the sands. The Flyer I was a canard design, believed by the Wrights to ensure greater control, but the first flight ended in a dive into the sand of the Kill Devil Hills as a result of over-correction of the forward elevator by Wilbur. It was damaged on the last landing and rather more thoroughly wrecked later by a gust of wind as Will and Orv, exhilarated beyond dreams, stood discussing their stupendous success with a group of spectators and helpers from the nearby Coast Guard station.
Unstable, underpowered, lightly loaded, difficult to control, the "Wright Flyer" flew. The five take-oils of 1903 totalled 99.5 seconds of airborne time. The total flying distance was 1,447 feet for an average ground-speed of just under ten miles an hour, achieved against winds of up to 25 m.p.h.
Those five historic flights were:-
Monday, December 14, 1903:
1. Wilbur Wright, 2.5secs, 100ft.
Thursday, December 17, 1903:
2. Orville Wright, 12secs, 120ft
3. Wilbur Wright, 11secs, 175ft
4. Orville Wright, 15secs, 200ft
5. Wilbur Wright, 59secs, 852ft
They were gaining in experience and their fuel capacity of half a gallon was sufficient for 18 minutes' duration.
The Wrights flights in December 1903 were the culmination of four years of carefully built-up experience and almost six hours of gliding airborne time in some 1,400 individual launches.
The Flyer I was unstable in pitch, flying in a series of divergent phugoidal swoops.
The Flyer is on display at Washington’s National Air & Space Museum.
First flight: 17 Dec 1903
Engine One 12 hp Wright
Wing span 40 ft 4 in (12.2 m)
Wing area: 510 sq.ft
Wing chord 6 ft 6 in
Length 21 ft 1 in (6.4 m)
Height 9 ft. 3 in
Weight empty 605 lb (275 kg)
Flight wt approx: 746 lb
Speed 30 mph (48 kph)
Ceiling 10 ft (3m) fully loaded
Range 852 ft (260 m)
No of flights: 5
Longest flight: 59 sec / 852 ft
Total flying time: 1 min 39.5 sec