Second prototype of Sopwith Bulldog |
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The Sopwith 2FR.2 Bulldog was a design for a two-man fighter-reconnaissance aircraft that was produced in one bay and two bay versions, but that didn’t enter production.
Sopwith produced two designs for fighter-reconnaissance aircraft in the summer of 1917. The Sopwith FR.2 was a two-bay biplane with a wingspan of 40ft 3in, armed with a single fixed forward firing Vickers gun, and with the pilot and observer sharing a single cockpit. This aircraft was to carry cameras and radio equipment, and to operate at high altitude. It didn’t go beyond the design stage.
The second design was the 2FR.2 Bulldog (originally called the Buffalo). This was originally designed and built as a single bay biplane, with a wingspan of 26ft 6in, making them shorter than on the single seat Sopwith Camel. The upper wings also had a large cut-out section in the trailing edge, and no centre section as this was where the pilot’s position was. However it was very heavily armed, with two fixed forward firing Vickers guns and two Lewis guns. It was to be powered by the new Clerget 11Eb rotary engine, a new design that was in rather short supply. Indeed the Bulldog had to share a single engine with the contemporary Sopwith 3F.2 Hippo. The observer had a long cockpit behind the wings, with a pillar mounted Lewis gun at each end
The single bay wings didn’t survive for long. They may have been used when Sopwith began flight tests in November, but had been replaced by a new set of two-bay wings with a longer span and horn-balanced ailerons by 13 November 1917. This wing was modified again before the aircraft went to Martlesham Heath for trials in May 1918, by which the horn balances had been removed. This aircraft was tested at Martlesham Heath with the number X3. It was put through mock combat with a Bristol Fighter, and was found to be about as manoeuvrable as that machine. However that wasn’t enough to justify putting the Bulldog into production.
It was followed by a second prototype, X4, this time powered by the new A.B.C. Dragonfly radial engine. X4 (or the Bulldog II) was built as an unarmed engine test-bed and was ready for tests in June 1918. This aircraft was used for tests well into 1919 and was at the RAE, Farnborough in March 1919, but the Dragonfly engine proved to be rather unreliable and the only significant improvement in performance was a superior climb rate which saw it reach 15,000ft in 16min 28sec, twice the speed of the Bulldog I.
Bulldog I
Engine: Clerget 11Eb
Power: 200hp
Crew: 2
Span: 33ft 9in
Length: 23ft
Height:
Empty Weight: 1,441lb
Maximum Weight: 2,495lb
Gross Weight:
Maximum Speed: 109mph at 10,000ft, 101.5mph at 13,000ft
Cruising Speed:
Climb rate: 6m 5s to 5,000ft; 15m 35sec to 10,000ft
Ceiling: 15,000ft
Endurance: 2 hours
Range:
Guns: Two fixed forward firing Vickers guns, two flexibly mounted Lewis guns.
Bomb load:
Sopwith Bulldog X-4 from the right 
Second prototype of Sopwith Bulldog from the right