he Blériot XI, largely designed by Raymond Saulnier,[2] 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 differences were 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, the engine was mounted directly in front of the leading edge of the wing and the bracing and warping wires were attached to a cabane structure made of 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, also of steel tubing, below it. When first built, it had a wingspan of 7 m (23 ft) and a small teardrop-shaped fin was mounted on the cabane,[3] but this 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 ingenuous design allowed crosswind landings with less risk of damage. A sprung tailwheel was fitted to the rear fuselage in front of the tailplane.
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[4] but although the aircraft handled well the engine proved extremely unreliable and, at the suggestion of his mechanic Ferdinand Collin, Blériot made contact with Alexandre Anzani, a famous motorcycle racer whose successes were due to the engines which 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 (or semi-radial) configuration engine, was fitted.[5] The propeller was also replaced with a Chauvière 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.[6]
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 m, 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
General characteristics
Crew: 1
Length: 7.62 m (25 ft 0 in)
Wingspan: 7.79 m (25 ft 7 in)
Height: 2.69 m (8 ft 10 in)
Wing area: 14 m2 (150 sq ft)
Empty weight: 230 kg (507 lb)
Powerplant: 1 × Anzani 3-cyl. Fan 25-30 hp 3-cyl. air-cooled fan style radial piston engine, 19 kW (25 hp)
Propellers: 2-bladed Chauvière Intégrale, 2.08 m (6 ft 10 in) diameter
Performance
Maximum speed: 75.6 km/h (47 mph; 41 kn)
Service ceiling: 1,000 m (3,281 ft)
