The Blériot XI, largely designed by Raymond Saulnier, was a development of the Blériot VIII, which Blériot had flown successfully in 1908. Like its predecessor, it was a tractor-configuration monoplane with a partially covered box-girder fuselage built from ash with wire cross bracing. The principal difference was the use of wing warping for lateral control. The tail surfaces consisted of a small balanced, "all-moving" vertical rudder with no fixed fin, at the very rear vertical member of the fuselage structure, and a single-level, horizontal tailplane surface with elevator surfaces comprising the outermost cell of the stabilizer's structure on each end, pivoting together with a torque tube running through the fixed inner sections linking the "tip elevators", mounted under the lower longerons of the fuselage. Like its predecessor, it had the engine mounted directly in front of the leading edge of the wing and the bracing and warping wires attached to a cabane structure made from steel tubing above the fuselage, with its five members oriented like the edges of a simple single-gabled house roof in shape, and an inverted four-sided pyramid-form ventral cabane, also of steel tubing, below it. When first built, it had a wingspan of 7 m (23 ft) and a small teardrop-shaped fin mounted on the cabane, which was later removed. The main undercarriage was also like that of the Type VIII, the wheels being mounted in castering trailing arms, which could slide up and down steel tubes, the movement being sprung by bungee cords. This simple and ingenious design allowed crosswind landings with less risk of damage. A sprung tailwheel was fitted to the rear fuselage in front of the tailplane, with a nearly identical castoring arrangement in its design to the maingear strutwork.
When shown at the Paris Aero Salon in December 1908, the aircraft was powered by a 35 hp (26 kW) 7-cylinder R.E.P. engine driving a four-bladed paddle-type propeller. The aircraft was first flown at Issy-les-Moulineaux on 23 January 1909, but although the aircraft handled well, the engine proved extremely unreliable and, at the suggestion of his mechanic Ferdinand Collin, Blériot made contact with Alessandro Anzani, a famous motorcycle racer whose successes were due to the engines that he made, and who had recently entered the field of aero-engine manufacture. On 27 May 1909, a 25 horsepower (19 kW) Anzani 3-cylinder fan-configuration (semi-radial) engine was fitted. The propeller was also replaced with a Chauvière Intégrale two-bladed propeller made from laminated walnut wood. This propeller design was a major advance in French aircraft technology and was the first European propeller to rival the efficiency of the propellers used by the Wright Brothers.
During early July, Blériot was occupied with flight trials of a new aircraft, the two-seater Type XII, but resumed flying the Type XI on 18 July. By then, the small cabane fin had been removed and the wingspan increased by 79 cm (31 in). On 26 June, he managed a flight lasting 36 minutes 55 seconds, and on 13 July, Blériot won the Aero Club de France's first Prix du Voyage with a 42 km (26 mi) flight between Etampes and Orléans.
The Channel crossing
The Blériot XI gained lasting fame on 25 July 1909, when Blériot crossed the English Channel from Calais to Dover, winning a £1,000 prize awarded by the Daily Mail. For several days, high winds had grounded Blériot and his rivals: Hubert Latham, who flew an Antoinette monoplane, and Count de Lambert, who brought two Wright biplanes. On 25 July, when the wind had dropped in the morning and the skies had cleared, Blériot took off at sunrise. Flying without the aid of a compass, he deviated to the east of his intended course, but, nonetheless, spotted the English coast to his left. Battling turbulent wind conditions, Blériot made a heavy "pancake" landing, nearly collapsing the undercarriage and shattering one blade of the propeller, but he was unhurt. The flight had taken 36.5 minutes and had made Blériot a celebrity, instantly resulting in many orders for copies of his aircraft.
The aircraft, which never flew again, was hurriedly repaired and put on display at Selfridges department store in London. It was later displayed outside the offices of the French newspaper Le Matin and eventually bought by the Musee des Arts et Metiers in Paris.
After the successful crossing of the English Channel, there was a great demand for Blériot XIs. By the end of September 1909, orders had been received for 103 aircraft. After an accident at an aviation meeting in Istanbul in December 1909, Blériot gave up competition flying, and the company's entries for competitions were flown by other pilots, including Alfred Leblanc, who had managed the logistics of the cross-channel flight, and subsequently bought the first production Type XI, going on to become one of the chief instructors at the flying schools established by Blériot.
In February 1912 the future of the Type XI was threatened by the French army placing a ban on the use of all monoplanes. This was the result of a series of accidents in which Blériot aircraft had suffered wing failure in flight. The first of these incidents had occurred on 4 January 1910, killing Léon Delagrange, and was generally attributed to the fact that Delagrange had fitted an over-powerful engine, so overstressing the airframe. A similar accident had killed Jorge Chavez at the end of 1910, and in response to this the wing spars of the Blériot had been strengthened. A subsequent accident led to a further strengthening of the spars. Blériot, understandably, took this matter very seriously, and produced a report for the French government which came to the conclusion that the problem was not the strength of the wing spars but a failure to take into account the amount of downward force to which aircraft wings could be subject to, and that the problem could be solved by increasing the strength of the upper bracing wires. This analysis was accepted, and Blériot's prompt and thorough response to the problem enhanced rather than damaged his reputation.
The Type XI remained in production until the outbreak of the First World War, and a number of variations were produced. Various types of engine were fitted, including the 120° degree Y-configuration, "full radial" three-cylinder Anzani (like the restored example at Old Rhinebeck Aerodrome still flies with) and the 50 hp (37 kW) and 70 hp (52 kW) Gnome rotary engines. Both single and two-seat versions were built, and there were variations in wingspan and fuselage length. In later aircraft the tip elevators were replaced by a more conventional trailing edge elevator, the tailwheel was replaced by a skid, and the former "house-roof" five-member dorsal cabane being replaced by a simpler, four-sided pyramidally framed unit similar to the ventral arrangement for the later rotary-powered versions. Blériot marketed the aircraft in four categories: trainers, sport or touring models, military aircraft, and racing or exhibition aircraft.
The Type XI took part in many competitions and races. In August 1910 Leblanc won the 805 km (500 mi) Circuit de l'Est race, and another Blériot flown by Emile Aubrun was the only other aircraft to finish the course. In October 1910, Claude Grahame-White won the second competition for the Gordon Bennett Trophy flying a Type XI fitted with a 100 hp (75 kW) Gnome, beating a similar aircraft flown by Leblanc, which force-landed on the last lap. During the race Leblanc had established a new world speed record. In 1911, Andre Beaumont won the Circuit of Europe in a Type XI and another, flown by Roland Garros, came second.
Louis Blériot established his first flying school at Etampes near Rouen in 1909. Another was started at Pau, where the climate made year-round flying more practical, in early 1910 and in September 1910 a third was established at Hendon Aerodrome near London. A considerable number of pilots were trained: by 1914 nearly 1,000 pilots had gained their Aero Club de France license at the Blériot schools, around half the total number of licences issued. Flight training was offered free to those who had bought a Blériot aircraft: for others it initially cost 2,000 francs, this being reduced to 800 francs in 1912. A gifted pupil favoured by good weather could gain his license in as little as eight days, although for some it took as long as six weeks. There were no dual control aircraft in these early days, training simply consisting of basic instruction on the use of the controls followed by solo taxying exercises, progressing to short straight-line flights and then to circuits. To gain a license a pilot had to make three circular flights of more than 5 km (3 mi), landing within 150 m (490 ft) of a designated point.
The first Blériot XIs entered military service in Italy and France in 1910, and a year later, some of those were used in action by Italy in North Africa (the first use of aircraft in a war) and in Mexico. The Royal Flying Corps received its first Blériots in 1912. During the early stages of the First World War, eight French, six British and six Italian squadrons operated various military versions of the aircraft, mainly in observation duties but also as trainers, and in the case of single-seaters, as light bombers with a bomb load of up to 25 kg.
Famous Blériot Monoplane pilots
- Oskar Bider – Swiss aviator who flew over the Pyrenees and the Alps in 1913.
- Baron Carl Calle Cederström, who made the first flight of a heavier-than-air craft in Norway on 14 October 1910. He made a flight of 23 minutes and reached a height of 300 metres (983.9 feet).
- Jean Conneau (André Beaumont) In 1911 won the Paris-Rome race, the Circuit d'Europe (Tour of Europe) on 7 July and the Daily Mail Circuit of Britain Race on 26 July 1911.
- Jorge Chavez – French-Peruvian aviator who crossed the Alps in 1910, but crashed on arrival and was killed.
- Denys Corbett-Wilson – Anglo-Irish aviator who made the first successful flight from Britain to Ireland in April 1912.
- Leon Delagrange – One of the first people to fly an aircraft in France, killed on 4 January 1910 flying a Blériot XI when a wing failed.
- Carlo Piazza - On October 22/23 1911, Captain Piazza of the Italian Royal Army Air Services conducted the first aerial reconnaissance flight between Tripoli & Aziza during the Italo-Turkish War.
- John Domenjoz (1886–1952) – Performed aerobatics in South, Central and North America in 1914–1918. His Gnome rotary-powered Blériot-XI is displayed at the National Air & Space Museum, Washington.
- Roland Garros - Won second place in the 1911 Circuit of Europe race, and set two world altitude records in 1912 in an adapted Type XI, flying to 5,000 m (16,000 ft) on 6 September 1912
- Claude Grahame-White Won the 1910 Gordon Bennett Trophy race held in New York flying a Blériot
- Eugène Gilbert – Went to the Blériot school in 1910 after having built his own small unsuccessful aircraft in 1909. During a flight across the Pyrenees Mountains in the 1911 Paris to Madrid air race he and his Blériot XI were attacked by a large eagle, which Gilbert drove off by firing a pistol.
- Tryggve Gran – Norwegian aviator, first to cross the North Sea from Scotland to Norway in 1914.
- Maurice Guillaux – French aviator, visited Australia April–October 1914. Flew Australia's first air mail and air freight from Melbourne to Sydney, 16–18 July 1914.
- Gustav Hamel – Flew the world's first regular airmail service between Hendon and Windsor in September 1911.
- Vasily Kamensky – a famous Russian Futurist poet, one of the pioneering aviators of Russia.
- Jan Kašpar – Czech aviator, first person to fly in Czech lands on 16 April 1910.
- Hubert Le Blon - A former racing car driver. He took up aviation and designed his own monoplane design. On April 2, 1910, flying a Bleriot XI, he became the second(after Delagrange) fatality of the type falling on to the rocks at San Sebastian, Spain.
- Alfred Leblanc – Broke the flight airspeed record on 29 October 1910 while flying a Blériot XI. His speed was calculated at 68.20 mph (109.76 km/h): on 11 April 1911 he raised the record to 111.8 kph
- Jan Olieslagers (1883–1942) – Lieutenant in the Belgian Army during the First World War.
- Earle Ovington – First airmail pilot in the United States, used a Blériot XI to carry a sack of mail from Garden City, New York to Mineo, Long Island
- Adolphe Pégoud – First man to demonstrate the full aerobatic potential of the Blériot XI, flying a loop with it in 1913. Together with John Domenjoz and Edmond Perreyon, he successfully created what is considered the first air show.
- Harriet Quimby – First licensed female pilot in the United States; first female to fly the English Channel solo.
- Rene Simon (1885-192?) – In February 1911, the Mexican government engaged Rene Simon, a member of an aerial circus touring the southwestern United States, to reconnoiter rebel positions near the border city of Juarez.
- Emile Taddéoli – Swiss aviator who first flew on 22 March 1910, in his newly bought Blériot XI, and flew about 150,000 kilometres (93,000 mi) during the next five years, using various aircraft, among them, the Blériot XI, Morane-Borel monoplane, Dufaux 4, Dufaux 5 and SIAI S.13 seaplane.
- Blériot XI (REP)
- Blériot XI (Anzani)
- Blériot XI Militaire
- Blériot XI Artillerie
- Blériot XI E1
- Blériot XI Type Ecole
- Blériot XI R1 Pinguin
- Blériot XI (1912)
- Blériot XI Parasol
- Blériot XIbis
- Blériot XI-2 Tandem
- Blériot XI-2 bis
- Blériot XI-2 bis "côté-à-côté"
- Blériot XI-2 Hydroaeroplane
- Blériot XI-2 Artillerie
- Blériot XI-2 Génie
- Blériot XI-2 Vision totale
- Blériot XI-2 Hauteur
- Blériot XI-2 BG
- Blériot XI-3 Concours Militaire
- Thulin A