The Vickers F.B.5 Gunbus (Fighting Biplane 5) was a British two-seat pusher military biplane of the First World War.
Armed with a single .303 in (7.7 mm) Lewis gun operated by the observer in the front of the nacelle, it was the first aircraft purpose-built for air-to-air combat to see service, making it the world’s first operational fighter aircraft.
Vickers began experimenting with the concept of an armed warplane designed to destroy other aircraft in 1912.
The first resulting aircraft was the “Destroyer” (later designated Vickers E.F.B.1) which was shown at the Olympia Aero Show in February 1913 but crashed on its maiden flight.
This aircraft was of the “Farman” pusher layout, to avoid the problem of firing through a tractor propeller and was armed with a single belt-fed Vickers gun.
Vickers continued to pursue the development of armed pusher biplanes, and their Chief Designer Archie Low drew up a new design, the Vickers Type 18, or Vickers E.F.B.2. This was a two-bay biplane powered by a single 80 hp (60 kW) Gnome Monosoupape nine-cylinder rotary engine; the aircraft had a steel tube structure, with fabric-covered wings and tail, and a duralumin-covered nacelle with large celluloid windows in the sides.
The unequal-span wings were unstaggered, with lateral control by wing warping, while the aircraft had a large semi-circular tailplane.
Armament remained a single Vickers gun mounted in the nose of the nacelle, with limited movement possible, and a very poor view for the gunner.
The E.F.B.2 made its first flight at Brooklands on 26 November 1913.
It was soon followed by the E.F.B.3, powered by a similar engine, but using ailerons instead of wing warping, and with equal-span wings, while the nacelle omitted the large windows fitted to the E.F.B.2.
The belt-fed machine gun proved problematic, and the weapon was changed to the lighter, handier, drum-fed .303 in (7.7 mm) Lewis gun.
The F.B.5 first flew on 17 July 1914.
It was powered by a single 100 hp (75 kW) Gnome Monosoupape nine-cylinder rotary engine driving a two-bladed propeller, and was of simple, clean, and conventional design compared with its predecessors.
In total, 224 F.B.5s were produced, 119 in Britain by Vickers, 99 in France and six in Denmark.
F.B.6
The Vickers F.B.6 was a development of the F.B.5 with an increased span on the upper wing.
Only one was built.
F.B.9
A further development of the F.B.5, the Vickers F.B.9, had a more streamlined nacelle and an improved ring mounting (either Vickers or Scarff) for the Lewis gun.
Fifty were delivered to Royal Flying Corps training units.
A few served in some F.E.2b squadrons while they were waiting for their new aircraft between late 1915 and early 1916.
Variants
E.F.B.2 (Vickers Type 18)
Single engined two-seat fighter prototype powered by 100 hp (75 kW) Gnome Monosoupape rotary engine.
It had a slight overhang on upper wings and wing warping controls.
Its nacelle was fitted with large celluloid windows and was armed with a single Vickers machine gun, One built.
E.F.B.3 (Vickers Type 18B)
Revised fighter, with equal-span wings, aileron controls and revised nacelle without windows, One built.
E.F.B.4
Proposed design of similar layout to “Destroyer” – unbuilt.
E.F.B.5
Further improved development of E.F.B.3.
Six built for RFC and RNAS.
F.B.5
Production version of E.F.B.5 with rectangular tail surfaces.
At least 120 built by Vickers, with 75 built by Darracq in France and 12 by the Tøjhusvoerkstedt (Danish Arsenal Workshops), giving a total of at least 207.
F.B.6
Pre-production aircraft, differing from E.F.B.5 by having revised unequal span wings with large overhang and ailerons only on upper wing, One built.
F.B.9
Improved derivative of F.B.5, with revised wings and tail, a more streamlined nacelle, a new V-type undercarriage and using streamlined Rafwire bracing instead of conventional cable bracing.
95 built by Vickers and 24 by Darracq, giving 119 in total.
Specifications
Crew
Two
Length
27 ft 2 in (8.28 m)
Wingspan
36 ft 6 in (11.13 m)
Height
11 ft 0 in (3.35 m)
Wing area
382 sq ft (35.5 m2)
Empty weight
1,220 lb (553 kg)
Gross weight
2,050 lb (930 kg)
Powerplant
1 × Gnome Monosoupape,
9-cylinder rotary engine,
100 hp (75 kW)
Performance
Maximum speed
70 mph (110 km/h, 61 kn) at 5,000 ft (1,500 m)
Range
250 mi (400 km, 220 nmi)
Endurance
4 hours 30 minutes
Service ceiling
9,000 ft (2,700 m)
Time to altitude
16 min to 5,000 ft (1,500 m)
Armament
Guns
1 × 0.303 in (7.7 mm) drum fed Lewis gun in observer’s cockpit.
