Bréguet 14. French users. Part one.

 

The Breguet 14 became the best French bomber of the World War I. It was designed by aeronautical engineer and aviation pioneer Louis Bréguet, who had already made himself a reputation for producing capable aircraft with innovative ideas, including the use of metal for aircraft construction. 

At the outbreak of World War I, Bréguet turned to the military industry, therefore, designing a number of versatile aircraft, such as the Br. 11, the Br. 5, which could act both as recon aircraft or even as heavy escort fighters. The firm, however, run out of orders and they switched to manufacture the Dorand AR.1 under license. Further development of the B.M. (the letter M stands for Michelin) pusher bomber series was ruled out as they proved to be ineffective in their role as day bombers and long-range escort fighters, so Bréguet realized that their next design should be capable of surviving the harsh environments of the Western Front. 

Despite of the official Aéronautique Militaire (French Air Arm) preference for pusher aircraft, Bréguet insisted on his AV idea (AV probably standing for "Avant" - tractor configuration) and, in June 1916, he began working on his design for a Renault-powered tractor biplane, with a wing with low wing loading. The AV 1 was also innovative for the widespread usage of duralumin, which, at the time, was only employed by the Germans in the airship construction, as this metal was light, resistant but too hard to work with. 

The first prototype, AV 1, was powered by a single 263 hp Renault engine, while the second prototype, AV 2, was powered by a 272 hp Renault engine, had a longer fuselage and was slightly heavier. Flight tests showed that the aircraft had a tendency to pull to the left, so vertical fin had to be offset slightly to the left. Upper wing was also given a sweepback to improve stability and give a better field of fire to the rear gunner. 

AV 1 flew for the first time on 21st November 1916 following six months of design and testing. Tests were carried out at Villacoublay, a village close to Paris, with Louis Bréguet at the controls. By January 1917 flight tests were completed and results showed that, for once, they had produced a bomber aircraft more advanced than any British (whose their Airco DH.4 was still under development) or German bomber of the time.

The AV 2, second prototype, was officially tested by the STAé (Section Technical Aéronautique - Aeronautics Technical Section) of the Aéronautique Militaire during early 1917, and it showed very promising results, being very useful for the day bomber role, hence they gave the AV 1 the official denomination of Bréguet 13 and the AV 2 the denomination of Bréguet 14. 

Bréguet received an initial order for 150 AV 1s, intended for reconnaissance on 6th March 1917 and that same day Michelin got another order for 150 AV 2s intended for the bomber role. The Bréguet 13 denomination was soon discarded and both variants received the Bréguet 14 denomination, with the "A" variant being the reconnaissance one and the "B" variant being the bomber one. 

From May 1917 onwards the type began to be introduced in many Escadrilles of the Aéronautique Militaire, most of them in the Western Front, although some few were also deployed on the Salonika Front. 

Some of those squadrons were:

• BR 7: Formed from SOP 7 in June 1917, this unit received the Br.14A.2 at Plessis-Bellevile, in the Oise department. In June it was sent to the Vosges front and was assigned to the 6e Corps De Armée (6th Army Corps). One year later, in 1918 it was sent to the Oise front to take part in the Battle of Picardie, and then to Bruthécourt, Meurthe-et-Moselle department, to take part in the Lorraine Offensive. After the war it was renamed as 7e Escadrille and, based at Dijon, was part of the 2e Régiment d'Aviation d'Observation (2e RAO).
• BR 504: Bomber Escadrille formed from V 388 on 14th June 1917. It was initially employed as a reconnaissance unit for the Armée Française d'Orient (AFO - French Army of the East). After the war it became the 5e Escadrille of the 7éme RAO. As it took part in the Salonika front, most of the bombing runs were carried out by other Escadrilles. See this post for more information.
• BR 218: Established from F 218 in late 1917, it was assigned to the 33éme Corps De Armée, and ended the War attached to the 10e Corps De Armée. One Br.14A.2 from this unit became famous for carrying King Albert I of Belgium during a flight.

Regarding the drawings, the B.1 variant, was a single-seat variant of the B.2 bomber with an enlarged wing area, automatic flaps and extra fuel tank in lieu of the original cockpit, as it was relocated to the observer's position. This variant was conceived by Jules Védrine as a long-range bomber to raid Berlin. It was tested by pilot De Bailliencourt, who found, while testing, that the Solex carburetor froze at altitude so he had to make a forced landing, provoking another prototype that was being tested at the same place and the same time, the Blériot 71 to crash-land while attempting to avoid the incoming Br.14B.1. 

The B.1 could carry up to 180 kg (397 lbs) of bombs with an endurance of up to seven hours. Two were ordered and Jules Védrine test-flew one machine from Paris to Cancale (in Brittany) in July 1917 in preparation for the raid on Berlin. However, the reluctance of the French Government to bomb German cities, as they feared retaliations, mixed with the marginally better performance of the B.1, when compared to the B.2, and its vulnerability against enemy fighters, led to the cancellation of the project.

Sources: 

1st Flying Machines Press  - French Aircraft of the First World War

2nd https://en.wikipedia.org/wiki/Bréguet_14