H.King Armament of British Aircraft (Putnam)
Robey-Peters Gun Carrier. In June 1916 J. A. Peters, who designed this large three-seat three-bay tractor biplane as a Zeppelin fighter, drew up a scheme for mounting gun (or engine) nacelles under the top wing of an aeroplane. It was slated that the gun mountings were placed above the nacelles 'on the top plane, which is cut away to facilitate operation of the guns'. On the aircraft as built, the nacelles were carried close inboard on two pairs of upright V struts. There were, in fact, two cut-outs in the upper surface of the wing above each nacelle, the rear ones, apparently, for the gunners, and the forward pair for the mountings to take two Davis recoilless guns. The pilot sat far aft in the mid-mounted fuselage.
W.Green, G.Swanborough The Complete Book of Fighters
ROBEY PETERS R.R.F.25 UK
Tests conducted in the USA led the British Admiralty to adopt the Davis recoilless gun for the RNAS, several types of aircraft being designed around this immense weapon, essentially for the anti-Zeppelin role. Among these was the Robey Peters R.R.F.25, designed by J A Peters for Robey & Company. Powered by a 250 hp Rolls-Royce 12-cylinder Vee-type water-cooled engine (later to be named Eagle), the R.R.F.25 was an unequal-span two-bay biplane with a crew of three comprising a pilot and two gunners. The pilot was accommodated far aft, immediately ahead of the vertical tail, and the gunners occupied nacelles suspended beneath the upper wing. The port nacelle accommodated a 0.303-in (7,7-mm) Lewis gun and the starboard nacelle housed a two-pounder version of the Davis gun which exceeded 7 ft (2,13 m) in length. Eight shells for the gun were fitted into the nacelle and two more in the adjacent wing. Two prototypes were ordered, the first of these flying in September 1916. It suffered minor damage as a result of turning over during the take-off run for what was to have been its second flight, and when it did succeed in getting airborne once more a fire at low altitude resulted in a crash in which it was destroyed. The second prototype, referred to as the Mk II, featured a new equi-span three-bay wing cellule, introduced a fixed tail fin, and side windows were added for the pilot. Overall span was reduced by 2 ft (61 cm) and wing area was increased by 63.5 sq ft (5,89 m2). It was intended that a Davis gun be carried in each nacelle. This aircraft was, in fact, cancelled by the Admiralty, but was completed nonetheless in January 1917 and flown during the course of the month. It stalled on take-off, however, and crashed, further work on the aircraft being finally abandoned. The following data relate to the first prototype.
Loaded weight, 3,700 lb (1678 kg).
Span, 54 ft 6 in (16,61m).
Length, 29 ft 4 1/2 in (8,95 m).
Wing area, 483.5 sq ft (44,92 m2).