P.Lewis The British Fighter since 1912 (Putnam)
Admiralty interest in fighters continued to increase with the result that, during the first months of 1916, the Port Victoria designers received a request from the Experimental Armament Section for a two-seat fighter layout required to be an effective gun-carrier.
Plans were commenced for a pusher project on a land undercarriage and powered with the 110 h.p. le Rhone. It would seem that this machine would have been the P.V.3 but the project did not reach fruition and was dropped in favour of a revised development on floats. This was designated P.V.4 and given the serial N8. An American-designed engine, the 10-cylinder Smith Static radial which delivered 150 h.p., was scheduled to power the P.V.4. Based on the output of this engine, the specification included a top speed of 80 kt., an initial climb rate of 5,000 ft. in 15 min., an endurance of 8 hours, wireless equipment and a Lewis gun for the gunner. The crew of two were housed in a trim, streamlined nacelle, to the top longerons of which were fitted the upper wings. The lower wings were considerably smaller than the upper set and the tail unit was carried on four slim booms. Stepped Linton Hope main floats formed the landing-gear, together with a single tail float, and a Scarff ring in the nose was used to enable the gunner to make the best use of an outstanding field of fire for his gun. The Smith Static, being produced in Britain by Heenan and Froude, was extremely slow in reaching production status, so that by the time that the P.V.4 was ready for its power unit in the Autumn of 1916 the Static was still not available. After continuing delay, a final effort was made in mid-1917 to get the P.V.4 airborne by installing a 110 h.p. Clerget. The Clerget’s greater length upset the balance of the machine completely and only considerable revision of the design could have rectified the faults. By this time the cleaner tractor with its synchronized forwards-firing gun was in the ascendant and development of the P.V.4, commendable design though it was, was dropped.
F.Mason The British Fighter since 1912 (Putnam)
Port Victoria P.V.4
Shortly after Port Victoria embarked on its P.V.2 anti-Zeppelin seaplane, work started on a two-seat pusher landplane fighter powered by a 110hp Le Rhone rotary. This aircraft was not built, and may have been designated the P.V.3. The design was, however, considered so favourably that Port Victoria was officially instructed to commence a twin-float derivative which became the P.V.4. Pursuing the P.V.2’s sesquiplane wing layout with upper wing attached to the crew nacelle’s top longerons, the resulting design was exceptionally compact, the gunner being located in the extreme nose with a Scarff ring-mounted Lewis gun forward of the pilot’s cockpit. The tail unit was carried on two pairs of converging booms attached to upper and lower mainplanes. Linton Hope floats were fitted from the outset.
The main problem lay in the official choice of the 150hp Smith ‘Static’ radial engine. The P.V.4’s airframe was completed during the autumn of 1916, but the Smith engine was never delivered and, in order to meet the stipulated maximum speed of 92 mph, only such engines as the 150hp Hispano-Suiza or 190hp Rolls-Royce Falcon would have sufficed - but neither could be fitted in the P.V.4. In the event recourse had to be made to a 110hp Clerget and, not surprisingly, the top speed performance fell far short of the target. Moreover, use of the Clerget moved the aircraft’s centre of gravity too far aft, and when the tailplane was rigged to counterbalance this, all longitudinal control was lost below 63 mph.
By that time, however, pusher fighters were regarded as de trop with the arrival of reliable gun interrupter gears, so it was not thought worthwhile to undertake the necessary redesign of the P. V.4’s tail unit, and its further development was therefore abandoned.
Type: Single pusher engine, two-seat twin-float sesquiplane fighting scout seaplane.
Manufacturer: RNAS Experimental Construction Depot, Port Victoria, Isle of Grain, Kent.
Powerplant: One 110hp Clerget 9Z nine-cylinder air-cooled rotary engine driving four-blade pusher propeller.
Structure: Wire-braced wooden box-girder central nacelle formed to near-circular section with wooden two-spar sesquiplane wings. Twin Linton Hope main floats and tail float.
Dimensions: Span, 32ft 0in; Weight: all-up: 2,400lb.
Performance: Max speed, 80.5 mph at sea level.
Armament: One 0.303in Lewis machine gun on Scarff ring in nose of nacelle.
Prototype: One, N.8 (first flown at the Isle of Grain in mid-1917). No production.
W.Green, G.Swanborough The Complete Book of Fighters
PORT VICTORIA P.V.4 UK
Early in 1916, the Marine Experimental Aircraft Depot initiated the design of a land-based two-seat fighter, the P.V.3. Although this was never built, the Depot was officially requested to develop a float seaplane version carrying radio equipment and a single 0.303-in (7,7- mm) machine gun. This, the P.V.4, was a small and compact sesquiplane with a central nacelle for the two crew members and a pusher engine, and the tail assembly carried by four slim booms. The gunner occupied the forward cockpit, which was equipped with a Scarff ring for the gun. The intention was to fit the P.V.4 with a 150 hp Smith "Static” radial engine but, as this was unavailable, a 110 hp Clerget rotary was installed for flight testing in mid-1917. This created CG problems, resolution of which would have involved considerable redesign, and, as the P.V.4 was considered to possess insufficient promise to warrant this work, development was discontinued.
Max speed, 81 mph (130 km/h).
Loaded weight 2,400 lb (1 089 kg).
Span, 32 ft 0 in (9,75 m).
Wing area, 220 sq ft (20,44 m2).
J.Bruce British Aeroplanes 1914-1918 (Putnam)
Port Victoria P.V.4
EARLY in 1916, the Experimental Armament Section asked Port Victoria to design a two-seat fighter.
The chief requirement was that the design must enable the most effective possible use to be made of a gun.
Preliminary drawings were prepared for a two-seat pusher landplane powered by a 110 h.p. Le Rhone rotary engine. The design seemed to hold promise, and was developed in some detail; presumably it was designated P.V.3. The machine was never built, however, for it was regarded so favourably that an official request was made for a seaplane of similar layout.
This seaplane version was to carry wireless apparatus and a Lewis gun, and was to have a flight endurance of eight hours; the specified maximum speed was 80 knots (92 m.p.h.), and the climb to 5,000 feet was to be made in 15 minutes. It was promised that a new radial engine, the 150 h.p. Smith “Static” would be supplied: this engine weighed only 380 lb and was reputed to have remarkably low fuel and oil consumption.
The initial calculations showed that, provided the engine gave its specified power, the required load could be carried and the performance achieved. Work was therefore begun on the seaplane, which was designated P.V.4. By the autumn of 1916 the airframe had been completed, but the promised engine was never delivered.
For a two-seat seaplane, the P.V.4 was remarkably small and compact. It was a nacelle-and-tailbooms pusher biplane with wings of unequal span. The upper wings were attached to the upper longerons of the nacelle, as on the P.V.2. The monoplane tail-unit was conventional; and the fin and rudder combined to form an almost circular surface. The lower tailbooms converged to meet at the bottom of the rudder-post.
The main floats of the undercarriage were of Linton Hope design, and the tail-float was similar to that of the P.V.2.
The gunner occupied the forward cockpit, on which was mounted a Scarff ring. From his position above the level of the upper wing he had an excellent field of fire for his gun.
When the non-appearance of the Smith engine held up the completion of the P.V.4, Wing Commander Aldwell made urgent representations to the Engine Section of the Air Department of the Admiralty. He obtained a promise that some engines would be delivered, but these materialised as a 150 h.p. Hispano-Suiza and a 190 h.p. Rolls-Royce Falcon, neither of which could be installed in the P.V.4. As a last resort, in the middle of 1917, the P.V.4 was assembled with a 110 h.p. Clerget rotary engine. The installation of this power-unit gave rise to a number of problems, for it was rather longer than the Smith radial, and it was found that the Clerget’s carburettor would come in the place occupied by the fuel tanks. By the time the necessary modifications had been made, the airscrew hub was nearly a foot further aft than the designed position.
The Clerget installation brought the centre of gravity too far aft and, with the airscrew much nearer the tailplane than it should have been, it proved to be impossible to make the machine longitudinally stable both with the engine on and off. With the tailplane rigged to give correct balance with full power the machine became tail-heavy with the engine off, and all longitudinal control was lost when the airspeed dropped below 55 knots (63 m.p.h.). Each landing was therefore something of an adventure, and only the strength of its Linton Hope floats saved the P.V.4 from an untimely end.
Redesign of the tail-unit could have remedied this fault, but the P.V.4 was no longer regarded as sufficiently important to justify the modifications. Machine-gun interrupter gears had meanwhile become available, but it is doubtful whether any other aeroplane of the 1914-18 war gave its observer a better field of fire than the P.V.4.
Manufacturers: R.N.A.S. Experimental Construction Depot, Port Victoria, Isle of Grain.
Power: 110 h.p. Clerget. (Designed for 150 h.p. Smith Static.)
Dimensions: Span: 32 ft.
Areas: Wings: 220 sq ft.
Weights: Loaded: 2,400 lb.
Performance: Maximum speed: 70 knots (80-5 m.p.h.).
Armament: One Lewis machine-gun on Scarff ring-mounting on front cockpit.
Service Use: Flown experimentally at Isle of Grain Test Depot.
Serial Number: N.8.
H.King Armament of British Aircraft (Putnam)
P.V.4. Another 1916 Port Victoria design, the P.V.4 pusher two-seater, did not fly until the following year. There was a Scarff ring-mounting for a Lewis gun in the nose, commanding a field of fire even over the top wing.