Short Knuckleduster
R.24/31 (S.18 Knuckleduster) | |
---|---|
Short S.18 'Knuckleduster' (K3574), at Felixstowe, 1934 | |
Role | General purpose flying-boat
|
Manufacturer | Short Brothers |
Designer | (Sir) Arthur Gouge[1] |
First flight | 30 November 1933 |
Retired | 1938 |
Status | Prototype |
Primary users | Short Brothers Marine Aircraft Experimental Establishment (MAEE), Felixstowe |
Produced | Rochester |
Number built | 1 |
The Short R.24/31 (or Short S.18 and nicknamed the Knuckleduster) was a British twin-engined, high-wing cantilever
Although it never saw military service, the Knuckleduster provided useful information on the steam-cooling of engines and the handling of monoplane flying-boats; much experimental data gathered contributed to the design of the successful
Design and development
The British Air Ministry issued its Specification R.24/31 for a "General Purpose Open Sea Patrol Flying Boat" in 1931 and ordered one prototype from each of Saunders-Roe, Supermarine and Shorts. Whereas the other two companies opted for traditional biplane designs, Shorts decided to produce a more modern, all-metal monoplane aircraft[1] with the experimental steam-cooled, cast block Rolls-Royce Goshawk engine, itself a development of the smaller Kestrel engine.
The Knuckleduster's straight-sided hull was of all-metal (Alclad) box-section construction, from the bow as far as the pointed main step at the rear of the planing bottom; aft of the main step the fuselage was of monocoque construction. The central section of the hull was boxed and braced by diagonal frames to bear the loads from the wing-root attachments.[3]
The wing sections inboard of the engines were attached at a 30°
The experimental 720 hp Rolls-Royce Goshawk steam-cooled engine was specified for the "Knuckleduster," which led to many problems due to the engine's unreliability. The engines, with conspicuous condensers protruding vertically from the nacelles, were mounted at the "knuckle" between the dihedral inner and the horizontal outer wing sections.
The tail unit comprised a horizontal plane braced by struts with two vertical fins and rudders, also supported by diagonal bracing to the fuselage. As a result of early test results, fin area was increased; a major redesign of the tail unit was requested by John Parker and implemented at considerable cost.
In addition to the enclosed cockpit in which the pilot and the navigator sat side by side, there was a gunner's cockpit in the bow, stations for the engineer and radio operator and a navigator station with a chart-table, sighting ports and two folding bunks. A third folding bunk and two fixed bunks were mounted in the crew's living quarters, which also included a galley and, further aft, stowage space for drogues and a lavatory.
Further armament was provided by a midships gun mounting and a rear gunner's cockpit in the tail; bombs could be mounted in underwing bomb racks and there was also provision for a
Operational history
First launched the previous day, the first flight of the prosaically named R.24/31 (
On 12 June 1934, at the conclusion of test flying, the Knuckleduster was flown to Felixstowe for official trials with the Marine Aircraft Experimental Establishment (MAEE).[5] The aircraft was judged not to meet the specification, particularly regarding top speed and range, even though these were not a priority in the specification. In October 1934 the boat was returned to Rochester for repair following an accident - a collision with another flying-boat. It was repaired and several modifications incorporated before it returned to Felixstowe in March 1935.
In April the Knuckleduster joined
Although it was not ordered into production - mainly hindered by the unreliable engines - a new Air Ministry Specification R.2/33 was released before it flew, which would lead to the Short Sunderland. The Sunderland was another large monoplane flying-boat that had benefited from the work on the R.24/31.
Operators
Specifications
Data from Shorts Aircraft since 1900 [7]
General characteristics
- Crew: 5
- Length: 63 ft 3 in (19.28 m)
- Wingspan: 90 ft 0 in (27.43 m)
- Height: 19 ft 6 in (5.94 m) [6]
- Wing area: 1,147 sq ft (106.6 m2)
- Airfoil: Göttingen 436 (outer wing sections)
- Empty weight: 11,720 lb (5,316 kg)
- Gross weight: 18,500 lb (8,391 kg)
- Powerplant: 2 × Rolls-Royce Goshawk VIII steam-cooled V12 engines, 775 hp (578 kW) each
- Propellers: 2-bladed wooden, 12 ft 6 in (3.81 m) diameter [8]
Performance
- Maximum speed: 150 mph (240 km/h, 130 kn)
- Range: 1,040 mi (1,670 km, 900 nmi)
- Service ceiling: 15,500 ft (4,700 m)
- Rate of climb: 800 ft/min (4.1 m/s) [8]
Armament
- Guns: 3 x Lewis Guns
- Bombs: underwing bomb racks for:[8]
- 2× 500 lb (230 kg) bombs or
- 4× 240 (110 kg) bombs
See also
- Saunders-Roe London
- Supermarine Stranraer
Related development
Aircraft of comparable role, configuration, and era
References
Notes
Bibliography
- ap Rees, Elfan. "Prototypes And Experimentals No 1: Short R.24/31". Air Pictorial, May 1971, p. 176.
- Barnes, Christopher H. and Derek N. James. Shorts Aircraft since 1900. London: Putnam, 1989. ISBN 0-85177-819-4.
- "The Short "Knuckleduster"" Flight 17 July 1935, Vol. XXVIII, No. 1385, pp. 56–58. Retrieved 28 March 2019.