F.Manson British Bomber Since 1914 (Putnam)

Sunbeam Bomber

   A contemporary o f the Sopwith B. 1, and approximating to its general configuration and purpose, was the Sunbeam Bomber, designed and built in response to encouragement from the Admiralty by a company which had not only produced numerous aircraft on behalf of other manufacturers, notably Short Bros, but also an impressive range of aircraft engines of its own design.
   For this reason the Admiralty appeared more generously disposed towards Sunbeam than Sopwith in this instance, ordering two prototypes o f the former company's Bomber while declining to offer support for the Sopwith B. 1. Unfortunately the Sunbeam aircraft proved a thoroughly inept design, and the Sunbeam engine chosen to power it, the 200hp Arab, was found to suffer from severe vibration which, for many months, defied rectification.
   The Sunbeam Bomber was a single-seat, two-bay biplane which, despite spanning 42 feet, did not feature folding wings. The bomb load, amounting to no more than 332 lb, was suspended from beneath the wings, and the 50-gallon fuel tank was located in the fuselage about the aeroplane's centre of gravity. The cockpit was therefore located well aft, some 13 feet from the nose of the aircraft, with a deplorable field of view for the pilot. His single synchronized Vickers machine gun was situated in the extreme nose and, being nine feet from the cockpit, was of course inaccessible in the event of a gun stoppage.
   At no time did the Admiralty suggest folding wings, nor would they have been possible as the upper wing possessed no centresection, the two halves meeting on the aircraft's centreline and being bolted to pyramidal cabane struts.
   The first example, N515, was flown during the latter half of 1917 at Castle Bromwich, but almost immediately encountered engine vibration which considerably delayed the Service trials; these eventually took place at Martlesham Heath in August 1918, and were only conducted to satisfy contractual obligations. The second aircraft was not completed, and N515 was not held on Air Ministry charge at the date of the Armistice.

   Type: Single-engine, single-seat, two-bay biplane naval bomber.
   Manufacturer: The Sunbeam Motor Car Co Ltd, Wolverhampton, Staffs.
   Powerplant: One 200hp Sunbeam Arab eight-cylinder, water-cooled, in-line engine driving two-blade propeller.
   Dimensions: Span, 42ft; length, 31ft 6in; height, 11ft; wing area, 466 sq ft.
   Weights: Tare, 1,915 lb; all-up (with three 100 lb bombs), 2,952 lb
   Performance: Max speed, 112.5 mph at 6,500ft; climb to 10,000ft, 14 min 20 sec; service ceiling, 18,500ft; endurance, 4. hr.
   Armament: Single fixed synchronized 0.303in Vickers machine gun located over engine; bomb load said to comprise three 100 lb bombs, carried externally.
   Prototypes: One, N515 (second aircraft, N516, not built). First flown late in 1917 at Castle Bromwich.

P.Lewis British Bomber since 1914 (Putnam)

The single-seat Sunbeam Bomber came from a firm which had been producing Shorts and Avros to meet Admiralty orders during the war and eventually decided to design its own bomber for the R.N.A.S. The result was the inauspicious single N515, a two-bay 42 ft. span biplane fitted with the 200 h.p. Sunbeam Arab engine. The pilot was located mid-way along the fuselage and was armed with one synchronized Vickers gun well out of his reach on the fore-decking; the bomb load was borne externally. The proportions of the Sunbeam Bomber did little to inspire confidence in the machine and, although tests were carried out in 1917 at Castle Bromwich and during the following year at Martlesham, it failed to earn a production order.

J.Bruce British Aeroplanes 1914-1918 (Putnam)

Sunbeam Bomber

  THE Sunbeam Motor Car Company, Ltd., of Wolverhampton were well-known as the manufacturers of the range of Sunbeam-Coatalen aero-engines. They also built aeroplanes: the Wolverhampton works produced Short 827s, Short 320s, Short Bombers and Avro 504Bs for the Admiralty.
  In 1917 the only all-Sunbeam aeroplane of the war period appeared. It was a single-seat two-bay biplane powered by a 200 h.p. Sunbeam Arab engine, and was in the same class as the Sopwith B.1 in size and performance. Test reports indicate that the Sunbeam Bomber was appreciably the heavier of the two machines and consequently had a smaller military load.
  The Sunbeam Bomber was an uninspired and unworkmanlike design. The designer had obviously decided to place the bomb-load and fuel tanks as close as possible to the centre of gravity, with the result that the pilot was situated well aft. His single Vickers gun was perched absurdly on top of the engine quite nine feet away from him, and beyond reach or remedy in the event of a stoppage.
  There was no upper centre-section: instead, the two halves of the upper mainplane were attached to a trestle-shaped cabane of the type favoured by German designers. The tail-unit bore some resemblance to that of the Sopwith Cuckoo.
  The Sunbeam Bomber first flew at Castle Bromwich in 1917 and was still flying in August, 1918, when it was tested at Martlesham. It is not surprising that it was not developed, for it combined an unsatisfactory engine with an ill-conceived airframe.


SPECIFICATION
  Manufacturers: The Sunbeam Motor Car Co., Ltd., Wolverhampton.
  Power: 200 h.p. Sunbeam Arab.
  Dimensions: Span: 42 ft. Length: 31 ft 6 in. Height: 11 ft.
  Areas: Wings: 466 sq ft.
  Weights and Performance: No. of Trial Report: M.222. Date of Trial Report: August, 1918. Type of airscrew used on trial: A.D.646. Weight empty: 1,915 lb. Military load: 332 lb. Pilot: 180 lb. Fuel and oil: 525 lb. Loaded: 2,952 lb. Maximum speed at 6,500 ft: 112-5 m.p.h.; at 10,000 ft: 109 m.p.h.; at 15,000 ft: 99-5 m.p.h. Climb to 6,500 ft: 8 min 10 sec; to 10,000 ft: 14 min 20 sec; to 15,000 ft: 28 min 5 sec. Service ceiling: 18,500 ft. Endurance: 4 1/2 hours at 15,000 ft.
  Armament: The bomb-load apparently consisted of three 100-lb bombs. A single fixed, forward-firing Vickers machine-gun was mounted externally above the engine, and was synchronised to fire through the airscrew.
  Serial Numbers: N.515-N.516.

H.King Armament of British Aircraft (Putnam)

Sunbeam

Bomber. This single-seat bomber of 1917 appears to have been unique among aircraft of the 1914/18 War in having a remotely-fired fixed Vickers gun. This was mounted above the engine several feet ahead of the single cockpit, where stoppages could not be cleared. In having external bomb stowage, it contrasted with the Sopwith Bomber, which ii somewhat resembled. J. M. Bruce slates that a bomb load of three 100-lb bombs was apparently possible. This type of bomb was a specialised anti-submarine weapon. Tandem tubular carriers suggest that a greater number of bombs was provided for, if not actually carried.