C.Andrews Vickers Aircraft since 1908 (Putnam)
Vickers fared a little better with their excursions into the tractor biplane field for multi-seat aircraft, after a poor start with the F.B.11 designed by Howard Flanders as a Zeppelin airship destroyer, for which purpose it had a fighting top mounted on the centre section of the upper wing. On a trial flight the F.B.11 proved to be deficient in control, and Harold Barnwell spent five weeks in Crayford hospital as a result. Its sole claim to distinction was that it was the first Vickers aeroplane to be powered with a Rolls-Royce engine, the early Eagle I of 250 hp.
F.B.11 - One 250 hp Rolls-Royce Eagle I. Span 51 ft; length 43 ft; height 15 ft; wing area 845 sq ft. Empty weight 3,340 lb; gross weight 4,934 lb. Max speed 96 mph at 5,000 ft; climb to 10,000 ft - 55 min; service ceiling 11,000 ft; absolute ceiling 12,000 ft; endurance 4 1/2 hr. Armament two Lewis guns.
H.King Armament of British Aircraft (Putnam)
F.B.11. Apparently intended primarily for anti-airship duties, though having obvious potential as an escort fighter, this single-engined three-seater of 1916 had two Lewis guns on Scarff ring-mountings. The foremost of these installations was in the nose of a nacelle carried forward from the upper surface of the top wing; the other was immediately behind the pilot, just aft of the wing trailing edges.
W.Green, G.Swanborough The Complete Book of Fighters
VICKERS F.B.11 UK
Designed by Howard Flanders as an airship destroyer, for which purpose it had an elevated gunner’s station, or "fighting top”, mounted on the centre section of the upper wing, the F.B.11 flew in late November 1916. Carrying a crew of three, including two gunners each provided with a 0.303-in (7,7-mm) Lewis gun, the F.B.11 was powered by a 250 hp Rolls-Royce Mk III 12-cylinder water-cooled engine - later to be named Eagle. The F.B.11 proved to be deficient in lateral control and the first prototype eventually crashed and was written off, a second example never being completed as, in the meantime, it had been realised that the entire concept of the large airship destroyer was fundamentally unsound.
Max speed, 96 mph (154 km/h) at 5,000 ft (1525 m), 81 mph (130 km/h) at 10,000 ft (3 050 m).
Time to 5,000 ft (1525 m), 16.5 min.
Ceiling, 11,000 ft (3355 m).
Endurance, 7.5 his.
Empty weight, 3,340 lb (1515 kg).
Loaded weight, 4,934 lb (2238 kg).
Span, 51 ft 0 in (15,54 m).
Length, 43 ft 0 in (13,10 m).
Height, 13 ft 8 in (4,16 m).
Wing area, 845 sq ft (78,50 m2).