The Bristol F.2B
The Bristol F.2 Fighter was a British two-seat biplane fighter and reconnaissance aircraft of the First World War developed by Frank Barnwell at the Bristol Aeroplane Company.
It is often simply called the Bristol Fighter, other popular names include the "Brisfit" or "Biff". Although the type was intended initially as a replacement for the pre-war Royal Aircraft Factory B.E.2c reconnaissance aircraft, the newly-available Rolls-Royce Falcon V12 engine gave it the performance of a two-seat fighter.
Despite a disastrous start to its career, the definitive F.2B version proved to be an agile aircraft that was able to hold its own against opposing single-seat fighters; its robust design ensured that it remained in military service into the 1930s.
Some surplus aircraft were registered for civilian use, and dedicated civilian versions proved popular. By Autumn 1915, the Royal Flying Corps (RFC) had identified the need for a new aerial reconnaissance and artillery spotting aircraft to replace the pre-war Royal Aircraft Factory B.E.2c.
Among other attributes and performance requirements, emphasis was placed upon the ability to defend itself in aerial combat.
Several new types were developed; the Royal Aircraft Factory responded with its R.E.8 design, while the Armstrong Whitworth Company produced the design that eventually emerged as the F.K.8. In March 1916, Frank Barnwell of the Bristol Aeroplane Company, commenced work on a new design also intended to serve as a replacement for the ageing B.E.2.
This initially took two forms, the Type 9 R.2A, to be powered by the 120 hp Beardmore engine, and the very similar Type 9A R.2B, powered by the 150 hp Hispano-Suiza.
Both designs featured the mounting of the fuselage between the wings, with a gap between the lower longerons and the wing, along with a substantial part of the vertical tail surfaces being located beneath the fuselage. These features were intended to optimise the field of fire for the observer; the positioning of the fuselage also resulted in the upper wing obscuring less of the pilot's field of view.
The crew positions were placed as close together as possible, to optimise communication between the pilot and observer. Before either the R.2A or R.2B could be constructed, the new 190 hp (142 kW) Rolls-Royce Falcon [V 12 cylinder engine ] became available; Barnwell now drafted a third revision of his design around the new engine, with its decidedly superior power/weight ratio. The anticipated improvement in performance changed the emphasis in its intended operational use; it was now seen as a replacement for the F.E.2d and Sopwith 1 1⁄2 Strutter two-seat fighters rather than a competitor with the pedestrian reconnaissance designs that were to replace the B.E.2. The resulting Type 12 F.2A, was a two-bay equal-span biplane, closely based on the R.2A and R.2B designs.
Prototypes Bristol Fighter prototype with B.E.2d wings.
Note column radiators on fuselage sides, forward of the wings. In July 1916, work commenced on the construction of a pair of prototypes; on 28 August 1916, an initial contract was awarded for 50 production aircraft.
On 9 September 1916, the first prototype performed its maiden flight, powered by a Falcon I engine.
It was fitted with B.E.2d wings (Bristol were major contractors for the type) to save time; its lower wings were attached to an open wing-anchorage frame and had end-plates at the wing roots. On 25 October 1916, the second prototype was completed, powered by a Hispano-Suiza engine, and otherwise differing from the first prototype in its tail-skid, which was integrated into the base of the rudder.
It was found that the prototype's radiator arrangement obscured the pilot's field of view, and the nose was redesigned around a new circular-shaped frontal radiator housed within the cowling.
Other changes made to the first prototype during flight testing included the elimination of the end-plates from the lower wing roots and the addition of a shallow coaming around the cockpits.
Between 16 and 18 October 1916, the type underwent its official trials at the Central Flying School, Upavon, during which it was tried with both a four-bladed 9 ft 2 in propeller and a two-bladed 9 ft 8 in propeller.
By the time of its arrival at the experimental armament station at Orfordness it had also been fitted with a Scarff ring mounting over the rear cockpit and an Aldis optical sight.
Only 52 F.2A aircraft were manufactured before production was switched to the definitive model, the F.2B (retrospectively designated Bristol Type 14 which first flew on 25 October 1916.
The first 150 or so F.2Bs were powered by either the Falcon I or Falcon II engine, but the remainder were equipped with the 275 hp (205 kW) Falcon III engine.
The additional power gave the F.2B a 10 mph (16 km/h) advantage in level speed over the F.2A, while it was three minutes faster in a climb to 10,000 ft (3,000 m).
Armament The Bristol F.2 Fighter was armed in what had by then become the standard weapons configuration for a British two-seater military aircraft: one synchronised fixed, forward-firing .303 in (7.7 mm) Vickers machine gun (in this case mounted under the cowling to avoid freezing) and a single flexible .303 in (7.7 mm) Lewis Gun on a Scarff ring over the observer's rear cockpit. The F.2B variant often carried a second Lewis gun on the rear cockpit mounting, although observers found the weight of the twin Lewis gun mounting difficult to handle in the high altitudes at which combat increasingly took place in the last year of the war, many preferring to retain a single gun.
Bristol Fighter with Foster-mounted Lewis gun Attempts were made to add a forward-firing Lewis gun on a Foster mounting or similar on the upper wing either instead of, or in addition to, the Vickers gun.
Among other problems this caused interference with the pilot's compass, which was mounted on the trailing edge of the upper wing: to minimise this effect the Lewis gun was offset to starboard.