H.King Armament of British Aircraft (Putnam)
P.V.7 (Grain Kitten). Designed specially for anti-Zeppelin operations from small naval craft, this tiny single-seat biplane of 1917 had a single Lewis gun above the centre-section, the trailing edge of which was cut away for elevation. Three drums of ammunition were specified.
P.Lewis The British Fighter since 1912 (Putnam)
The next designation in the Port Victoria design series, P.V.6, was allotted to an uncompleted project for a fast scout landplane. Attention was next turned to meeting a call for a very small, low-powered scout capable of being flown from minor warships. The engine specified was the two-cylinder, geared 45 h.p. A.B.C. Gnat. Besides the Port Victoria Depot, the Experimental Flight at Eastchurch was asked also to submit a design.
Each machine was a diminutive biplane, that designed at Port Victoria being designated the P.V.7, while the Eastchurch-conceived machine, through transference to Port Victoria for completion, became the P.V.8. Respectively, the aircraft were called the Grain Kitten and the Eastchurch Kitten.
Both types constituted early examples of the often-attempted light fighter, each being a well-conceived and competent approach to an interesting challenge.
Grain’s P.V.7 was the smaller of the two, following the normal layout for a single-seat, single-bay biplane of unequal span and showed traces in its outline of its predecessors from the same design source.
The Eastchurch Kitten was rather more angular and of cleaner cut than the Grain machine and received equal-span wings, set with accentuated stagger on single I-type interplane and centre-section struts.
Both the P.V.7 and P.V.8 were forced to use the lower output of the direct-drive 35 h.p. A.B.C. Gnat as the 45 h.p. version of the engine was not available. Each was armed with a single Lewis gun on the upper centre-section and each machine was modified in several respects after completion in mid-1917 and, of the pair, the P.V.8 showed itself to be the superior aeroplane.
F.Mason The British Fighter since 1912 (Putnam)
Port Victoria P.V.7 and P.V.8
Early in 1916 the Admiralty directed the Experimental Construction Depot at Port Victoria and the Experimental Flight at Eastchurch to examine the feasibility of producing a small scout capable of taking off from a very short platform aboard a Torpedo-Boat Destroyer, specifying the use of a geared 45hp ABC Gnat engine.
Both agencies produced independent designs, Capt W H Sayers rfc producing the P.V.7 at Port Victoria; at Eastchurch, Lieut G H Millar rnvr devised a rather different sort of aircraft. However, when Sqn Cdr H R Busteed moved from Eastchurch to assume command of Port Victoria, he took with him both Millar and his design, which was then designated the P.V.8. To differentiate between their design origins, the P.V.7 came to be called the Grain Kitten, and the P.V.8 the Eastchurch Kitten.
The P.V.7 was unquestionably the more attractive of the two, with sesquiplane wings, outward canted and paired interplane struts, gracefully tapering fuselage in plan and low aspect ratio ailerons on the top wing only. There was a spigot-mounted Lewis gun above the wing. However, tested first on 22 June 1917, the P.V.7 proved difficult to handle on the ground, and tail-heavy in the air; moreover the sesquiplane layout, with high-lift wings, was shown to be unsuitable for the tiny aeroplane.
By contrast, the aesthetically less-pleasing Eastchurch Kitten was much more successful. It featured heavily staggered single-bay wings of equal span employing I-form interplane and cabane struts from a crashed Sopwith Triplane, and when first flown on 7 September, it featured a balanced elevator without fixed tailplane. The pilot, Harry Busteed himself, reported severe longitudinal instability, with the result that a fixed tailplane was added, and much of the elevator horn balance was removed. To provide some shock absorption during landing, very big landing wheels with large-section tyres were fitted.
As with almost all Port Victoria’s aircraft, the engines promised for the two Kittens never materialised, and both aircraft had to be modified to take the direct-drive 35hp version of the ABC Gnat. This engine, designed by Granville Bradshaw, was an ingenious horizontally-opposed twin-cylinder aircooled engine weighing 115lb dry. Yet, despite the obvious success of the P.V.8, and the ease with which it could be flown, interest in the idea was shortlived.
Type: Single-engine, single-seat, single-bay lightweight biplane scout.
Manufacturer: RNAS Experimental Construction Depot, Port Victoria, Isle of Grain.
Powerplant: One direct-drive 35hp ABC Gnat horizontally-opposed two-cylinder aircooled engine.
Dimensions: P.V.7. Span, 18ft 0in; length, 14ft 11in; height, 5ft 3in; wing area, 85 sq ft. P.V.8. Span, 18ft Oin; length, 15ft 7 1/2 in; height, 5ft 5in; wing area, 106 sq ft.
Armament: Both aircraft equipped to carry one 0.303in Lewis gun above wing centre section.
Prototypes: P.V.7, N539 (first flown by H R Busteed on 22 June 1917). P.V.8, 540 (first flown by Busteed on 7 September 1917). No production.
W.Green, G.Swanborough The Complete Book of Fighters
PORT VICTORIA P.V.7 (GRAIN KITTEN) UK
To meet a requirement for a diminutive lightweight single-seat airship interceptor suitable for operation from platforms on relatively small seagoing vessels, the Depot produced the P.V.7 to the designs of W H Sayers. To become known as the Grain Kitten to distinguish it from a competitive design created by the RNAS Experimental Flight at Eastchurch (which accordingly became known as the Eastchurch Kitten), the P.V.7 was an extremely small sesquiplane intended to be powered by a 45 hp geared ABC Gnat two-cylinder air-cooled engine. Armament consisted of a single 0.303-in (7,7-mm) machine gun mounted above the wing centre section. Unavailability of the geared Gnat engine led to installation of a 35 hp direct-drive Gnat with which the P.V.7 was completed in the summer of 1917. Difficulties were experienced with the engine from the start of flight testing in June, the aircraft being tail-heavy and performance disappointing. A series of modifications was introduced, but the P.V.7 was not flown subsequently.
Max speed, 89 mph (143 km/h) at 2,000 ft (610 m).
Time to 6,500 ft (1980 m), 10.8 min.
Empty weight, 272 lb (123 kg).
Loaded weight, 491 lb (223 kg).
Span, 18 ft 0 in (5,49 m).
Length, 14 ft 11 in (4,55 m).
Height, 5 ft 3 in (1,60 m).
Wing area, 85 sq ft (7,90 m2).