The Breguet 14 was designed by aviation pioneer and aeronautical engineer Louis Breguet. By this point, Breguet's company had already built up a reputation for producing several capable aircraft and advanced aerodynamic test apparatus, including the Breguet-Richet Gyroplane, which held the distinction of being the first direct-lift aircraft in the world. Breguet had been a key innovator in the field of all-metal construction, which he had employed on a successful series of biplanes during the pre-war years; these principal would be applied in the designing of the Breguet 14 as well.
The outbreak of the First World War in 1914 quickly led to large numbers of Breguet-built aircraft being inducted into the military air services of several nations, including many of the nations in the Triple Entente. Breguet himself flew as a military pilot early on in the war, and soon recognised there was demand for aircraft fitted with more powerful engines in order to carry worthwhile payloads over anything beyond short distances. For his next design, he opted to abandon his previously-favoured tractor configuration in favour of a pusher configuration to better satisfy the inflexible requirements issued by the French general staff, which sought an unobstructed frontal viewpoint to benefit the observer.
During the summer of 1915, the French Ministry of War held a competition, seeking to determine the most suitable type of aircraft to carry a bombload of 300 lb at a speed of 120 km/h over a minimum distance of 600 km. Following an extensive evaluation, Breguet's submission to the contest, SN-3; reportedly, a major reason for its selection over more powerful rivals was its use of the desired pusher configuration. The SN-3 would be developed into the Breguet Type IV, V, and VI, which would be built in large quantities for military use.
In spite of the expressed preference of French officials for the pusher configuration, Breguet remained a proponent of tractor aircraft. During June 1916, he decided to initiate work on a clean-sheet design for a military-oriented two-seater aircraft, which was assigned the designation of Breguet AV Type XIV. According to aviation authors J.M Bruce and Jean Noel, the French Army's Section Technique de l' Aéronautique (S.T.Aé.) received early information on the design and recommended that Breguet power it using a 200 hp engine by Hispano-Suiza. However, Breguet found that the engine would be incapable of delivered the desired performance, instead insisting on the adoption of a 12-cylinder Renault-built engine that had been powered the previous Breguet Type V.
The Breguet Type XIV was both a practical and aesthetically pleasing design. A distinctive characteristic of the Type XIV was its rectangular frontal radiator, as well as the shape of is cowling and the negative-stagger of its mainplanes. It possessed a sturdy undercarriage, along with two-part ailerons on the upper wing only. On the prototype, the lower wing reportedly featured flaps along the trailing edges, that partly emulated the manner of operation of "single-acting ailerons" in only "coming up" from their "down" position at rest, as the aircraft accelerated during takeoff; these possessed a limited angle of depression and were not directly controlled by the pilot, instead being actuated by a set of 12 adjustable rubber bungee cords.
The airframe was composed primarily of duralumin, invented in Germany by one Alfred Wilm a decade earlier; many sections, such as the duralumin longerons and spacers, were attached using welded steel-tube fittings and braced using piano wire. The wing's main spar were rectangular duralumin tubes complete with either oak or ash lining-pieces at the attachment points and sheet steel sheaths around the spars. The box-unit wooden ribs had fretted plywood webs and ash flanges. The surfaces of the tail unit used welded steel tube structures; while the elevators featured horn balances. During its design phase, French officials were wary of the Type XIV's structure, having made such an extensive use of the relatively new metal duralumin that it was claimed to be the first aircraft in the world to combine heavy use of the metal with oxy-welded joints.
On 21 November 1916, the first prototype conducted its maiden flight, flown by Breguet himself. The first flight had confirmed Breguet's opinion that the Renault engine was more suitable for the type; on 30 November 1916, he informed the S.T.Aé of this determination and of the comparably worse performance of their recommended engine. On 11 January 1917, Breguet informed the S.T.Aé that the prototype had reached the point where he considered it to be representative of production-standard aircraft. Later that month, it participated in further trials and, by 7 February 1917, the S.T.Aé had issued a report, declaring that the prototype had attained an air speed of 172 km/h at an altitude of 2,000 meters.
During November 1916, the S.T.Aé. had issued its requirements for four different new aircraft types. Breguet submitted his new design for two of those categories - reconnaissance aircraft, and bomber. Following its evaluation during February 1917, the Breguet 14 had been accepted to perform both of these roles. On 22 February 1917, Breguet pressed the S.T.Aé for a production order to be issued for the type; on 2 March, he declared that production jigs had been prepared for quantity production of the type. On 6 March 1917, the first official production order was received by Breguet, calling 150 aircraft, designated as the Breguet 14 A.2; a follow-on order for a further 100 aircraft was received on 4 April.
Mass production and further development
By March 1917, several orders had been placed, calling for a combined 150 reconnaissance aircraft and 100 bombers, designated "Breguet 14 A.2" and "14 B.2" respectively (by 1918, it was written as Breguet XIV A2/B2). The A.2 variant was equipped with an array of cameras, while some were also provisioned with radios, while the lower wing of the 14 B.2 was modified slightly in order to accommodate bomb racks (built by Michelin), capable of housing up to 32 115 mm calibre bombs. To avoid the bomb racks conflicting with operation of the flaps, a small forward extension of the wings was added; another modification was the installation of transparent panels to the sides of the observer's cockpit to aid in the operation of the bomb sight.
By mid-1917, French authorities had expressed a high level of confidence in the type in the form of a substantial expansion of the type's production. Various other companies were contracted to manufacture the type. On 25 April, French aviation company Darracq was requested to manufacture 330 aircraft. On 8 June, another 50 were ordered from
Société des avions Henri & Maurice Farman; on 18 June,
Paul Schmitt was issued a contract to produce 200 aircraft. Some of the contractors were unable to commence quantity production of the Breguet 14 until 1918. Following the war, a handful of aircraft were constructed in French military-owned workshops in Indo-China, albeit these are likely to have been heavily reliant upon the availability of spare parts.
As an insurance against engine shortages, alternative engines to use in place of the standard Renault powerplant were fitted on some aircraft, both for experimental purposes and in production quantities. An improved model of the standard engine, referred to as the Reanault 12Ff, appeared in Summer 1918 and was used on some later-built aircraft. Another engine adopted was built by French automotive company Lorraine-Dietrich, which was lighter but produced less power than the Renault unit. A number of Belgian and American Breguet 14s were outfitted with the Fiat A.12 engine. A number of later-built B2 models were equipped with the U.S.-built Liberty engine; to distinguish these aircraft, they were denoted as the Breguet 14 B2 Ls.
Other minor variants of the Breguet 14 were flown in small numbers during the Great War; these included the 14 B.1 long-range single-seat bomber, the 14 GR.2 long-range reconnaissance, the 14 H floatplane, the 14 S air ambulance and the 14 Et.2 trainer. Later variants, such as the 14bis A2 and 14bis B2, featured improved wings. An improved variant equipped with enlarged wings was produced as the 16. Further derivatives of the aircraft included the two-seat fighter 17, which would only be built in small numbers due to its late arrival. Production of the base Breguet 14 continued long after the end of the war, finally ending in 1926.