F.Manson British Bomber Since 1914 (Putnam)
Wight Admiralty Type 840
The appearance of the 225hp Sunbeam engine encouraged not only Short Bros to embark on their successful Type 184, but also the East Cowes company of J Samuel White, whose chief designer, Howard T Wright, recognised that an engine of this power made possible a torpedo-carrying seaplane, capable of realising Admiralty demands for a worthwhile range as well as a relatively heavy warload. The ensuing design was the Admiralty Type 840, so designated from the serial number of an example in the first production batch ordered, Nos 831-840.
The Type 840 was an almost exact contemporary of the Short 184 and, despite featuring four-bay wings, possessed a closely comparable performance. Moreover, on account of much longer, three-step main floats, the Wight seaplane could dispense with a tail float. The 14in torpedo was held by crutches on the rear three inter-float ties, and would have been partly submerged when the aircraft was resting on the water.
Although the Short was probably recognised from the outset as being the superior aircraft, the Admiralty clearly felt Wright's design worthy of production orders, and 52 examples (from at total of 68 ordered) came to be built, though none ever joined an operational unit of the RNAS, serving instead at various naval ports, perhaps occasionally performing coastal patrols.
Just as the Short 184 came to provide the basis of a landplane bomber, which was built in numbers and reached operational service (see Short Bomber), Whites produced a landplane version of their Type 840, retaining the four-bay wings. Small changes were made to the tail unit, the tailplane being raised to top of the fuselage. A much simpler twin mainwheel undercarriage replaced the floats, incorporating a small, forward-rigged wheel to avoid the possibility of grounding the propeller during landing. Unlike the Short, the Wight landplane inherited a long slim fuselage, and one is perhaps able to conjecture that handling of this version would have been superior to that of the original Short 184 landplane. Bomb load would probably have been of the order of eight 65 lb bombs in place of the seaplane's 810lb torpedo. It has been suggested that at some time in its life a 275hp Rolls-Royce engine might have been fitted, but as far as is known only one example of the landplane was completed.
Type: Single-engine, two-seat, four-bay biplane torpedo-bomber seaplane.
Manufacturers: J Samuel White & Co, East Cowes, Isle of Wight; William Beardmore & Co Ltd, Dalmuir, Dumbartonshire; Portholme Aerodrome Ltd, Huntingdon.
Powerplant: One 225hp Sunbeam eight-cylinder, water-cooled, in-line engine driving two-blade propeller.
Dimensions: Span, 61ft; length, 41ft; wing area, 568 sq ft.
Weights: Tare, 3,408 lb; all-up (with 810 lb torpedo), 4,810 lb.
Performance (without torpedo): Max speed, 81 mph at sea level; max endurance, 7 hr.
Armament: Either one 810 lb 14in torpedo or equivalent weight of bombs; no provision for gun armament.
Production: A total of 68 Type 840s was ordered, of which 52 were built. White, 24 (Nos 831-840, 1300-1319 and 1351-1354); Beardmore, 25 (Nos 1400-1411 and 9021-9033); Portholme, 3 (Nos 8281-8283). The remainder were delivered as spares (Nos 8284-8292 and 9034-9040).
Summary of Service: Wight Type 840s served at a number of RNAS Seaplane Stations, including Felixstowe, Scapa Flow and Gibraltar.
P.Lewis British Bomber since 1914 (Putnam)
Among the machines from J. Samuel White and Company which achieved quantity production was the Wight Admiralty Type 840 seaplane, a two-seat tractor biplane fitted with the 225 h.p. Sunbeam. The 61 ft. span, four-bay, folding wings possessed a moderate amount of overhang of the upper planes, in which were incorporated the long-span ailerons. The wing section embodied the double-camber idea with its depression in the upper curve of the aerofoil. Twin main floats were attached to the simple type of fuselage by a complex arrangement of struts; as a torpedo-carrier the cross-braces between the floats were arched, but later examples which were not intended to launch a 14 in. torpedo appeared with straight cross-struts. The Sunbeam received its cooling through twin radiators, one of which flanked the engine on each side. The Type 840 was employed at a number of R.N.A.S. coastal stations, but was unable to match the lustre which attached to its contemporary, the Short Type 184.
A landplane version of the Wight Type 840 was constructed using, among other modifications, a nosewheel main undercarriage reminiscent of the Grahame-White Type 18.
O.Thetford British Naval Aircraft since 1912 (Putnam)
WIGHT ADMIRALTY TYPE 840 SEAPLANE
The Wight Type 840 was designed as a torpedo-carrying seaplane to the same requirements as the more famous Short Type 184. It could carry a single 810 lb 14 in torpedo, but there are no records of this weapon having been used in action. It served with the RNAS at Felixstowe, Scapa Flow and Gibraltar on anti-submarine patrol between 1915 and 1917. No.835 (illuistrated) was one of the batch 831 to 840 built by the parent company, which also produced Nos.1300 to 1319 and 1351 to 1354. About 70 Wight 840 seaplanes were delivered to the RNAS, including sub-contracted aircraft by Beardmore of Dalmuir and Portholme of Huntingdon. A landplane version also existed. One 225 hp Sunbeam engine. Loaded weight, 4.453 lb. Maximum speed, 81 mph. Span, 61 ft. Length, 41 ft.
H.King Armament of British Aircraft (Putnam)
Type 840. Like its counterpart the Short 184, this twin-float seaplane was designed to carry a 14-inch torpedo. On the first few machines the bracing-ties between the floats were arched accordingly, but these members were later made straight, and a bomb load of considerably less than the torpedo's weight was carried. A Wight seaplane of unspecified type was used in 1915 for bombing experiments at Calshot.
M.Goodall, A.Tagg British Aircraft before the Great War (Schiffer)
Deleted by request of (c)Schiffer Publishing
Jane's All The World Aircraft 1919
Type 840 TRACTOR SEAPLANE
Length: 41 ft.
Span: 61 ft.
Surface: 568 sq. ft.
Weight empty: 3408 lbs.
Useful load: 1045 lbs.
Engine: 225 h.p. Sunbeam.
Speed: 81 m.p.h.
Endurance: 4 hours.