Dubbed unofficially the Streamline Gunbus, the F.B.9, which emerged towards the end of 1915, introduced numerous refinements over its predecessor, the F.B.5. The fuselage nacelle was of improved aerodynamic form; the wings and tailplane sported rounded tips; streamlined Rafwires replaced stranded steel cables and turnbuckles for interplane bracing, and a plain, Vee-type undercarriage supplanted the twin skids previously used.
The standard power plant remained the 100hp Gnome Monosoupape rotary. Vickers built a total of 95 F.B.9s, and a further 20-30 were built by Darracq in France, some of which were issued to the RFC (No 11 Sqn) and were used during the Battle of the Somme which began on 1 July 1916. The manufacture of the F.B.9 in Italy by Vickers-Terni fell through owing to political reasons.
The only FB.9s known to have seen operational service were seven examples (Serials 7812, 7813, 7820, 7826, 7827 and 7828), all of which were flown on war patrols by 11 Squadron RFC in France in June-July 1916. On July 1, 7828 gained a confirmed aerial combat victory. All other FB.9s were relegated to RFC and RNAS training units, where they gave faithful service until late 1918. As trainers, several FB.9s were modified to have dual controls, and many had a Scarff ring fitted in the front cockpit for gunnery practice. At least one FB.9 was armoured and fitted with an oleo undercarriage. None remained on charge at the time of the Armistice.
Engine: 100-hp Gnome Monosoupape rotary, or 110-hp Le Rhone rotary
Span: 10.3 m (33 ft 9 in)
Length: 8.7 m (28 ft 5.5 in)
Height: 3.5 m (11 ft 6 in)
Wing area: 31.59 sq.m / 340.03 sq ft
Max take-off weight: 858 kg / 1892 lb
Empty weight: 467 kg / 1030 lb
Maximum speed: 132.9 km/h (82.6 mph) at ground level
Climb to 3048 m (10000 ft): 51 min
Service ceiling: 3353 m (11000 ft)