Short Seamew
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| SB.6 Seamew | |
|---|---|
 Seamew prototype XA213 |
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| Type | Anti-submarine aircraft |
| Manufacturer | Short Brothers |
| Maiden flight | 23 August 1953[1] |
| Retired | 1957 |
| Primary users | Royal Navy Fleet Air Arm Royal Naval Volunteer Reserve |
| Number built | 19 |
The Short SB.6 Seamew was a curious-looking British aircraft designed in 1951 by David Keith-Lucas of Shorts as a lightweight anti-submarine platform to replace the Royal Navy Fleet Air Arm (FAA)'s Grumman Avenger AS.4. It first flew on 23 August 1953, but, due to poor performance coupled with shifting defence doctrine, it never reached service and only nineteen were built before the project was cancelled. It has been described as a "camel amongst race-horses".[2]
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[edit] Design and development
The Short Seamew was selected to fulfill Admiralty Specification M.123D for a simple, lightweight anti-submarine aircraft capable of unassisted operation from any of the Royal Navy's aircraft carriers in all but the worst of conditions. It was to be suitable for mass production and operation by the Air Branch of the RNVR. This specification was in response to the alarming increase in capabilities of the Soviet submarine forces following the Second World War.
The first flight of the Seamew, piloted by its test pilot, Walter J. "Wally" Runciman,[3] took place on 23 August 1953.
[edit] Design
The pilot and observer were located in tandem cockpits located high up in the front of the deep, narrow fuselage. They sat atop the Armstrong Siddeley Mamba turboprop in front and the weapons bay to the rear of them. The design had originally called for the tried and tested Rolls-Royce Merlin V12 piston engine but the Royal Navy had made it policy to phase out piston engines, in order that supplies of highly flammable high octane aviation fuel need not be carried in large quantities on ships. The turboprop engine also caused less airframe vibration and would therefore impact less on the performance of the radar scanner mounted below the engine housing.
For simplicity, and so that a nose-wheel would not obscure the forward field of the radar scanner, a fixed tail-wheel undercarriage was fitted. The long stroke necessary to clear the radar scanner and propeller from the ground resulted in an alarming attitude on the ground and the cockpits seemingly mounted at a perilous height. The pilot and observer sat very far forward in order that the pilot could have a reasonable field of downward vision for takeoff and landing and so that both he and the observer had a good field of view for e.g. submarine spotting even when in level flight.
The large, broad-chord wings featured power-folding and pylons for the carriage of rockets, depth charges, flares and small bombs. The large, slab-like tail-plane was mounted high on the vertical stabiliser, requiring the rudder to be split into upper and lower sections. The fixed undercarriage legs could be jettisoned in the event of ditching.[4]
[edit] Handling Characteristics
The handling characteristics of the Seamew were poor. The prototypes were heavily modified with fixed leading-edge slats, slots added in the trailing-edge flaps, alterations to the ailerons and slats added to the tailplane roots. Although something of an improvement over the initial models, the handling was never wholly satisfactory. Arthur Pearcy wrote "only Short Brothers' test pilot Wally Runciman seemed able to outwit its vicious tendencies and exploit its latent manoeuvrability to the limit."[5][6]
[edit] Operational service
An order was placed in February 1955 for 60 aircraft (split evenly between the FAA and RAF), with Seamew XA213 successfully completing carrier trials on HMS Bulwark in July and December 1955. Naval service flight trials with two Seamews were carried out with 700 Naval Air Squadron in November 1956, which included catapult trials and around 200 takeoffs and landings on HMS Warrior. The RAF lost interest after four MK 2s were built (with larger wheels and manual wing folding),[7] and three of them were converted to AS1 standard; the fourth (XE175) was flown by W.J. Runciman for a series of sales tours in 1956 to Italy (March), Yugoslavia (April) and West Germany (May). It was this same aircraft in which S/L Wally Runciman was killed when it crashed during the Sydenham (Belfast) Air Display on 9 June 1956. Rumours that the crash had been caused by a material failure were current at the time but the accident investigation board did not confirm them.
Meanwhile the FAA decided that the RNVR Avengers would be replaced by Seamews, but only four had been taken on charge by the time the RNVR squadrons were disbanded in March 1957 in keeping with the 1957 Defence White Paper, before any Seamews were allocated to them. Seven aircraft eventually delivered to the FAA were scrapped at RNAS Lossiemouth, and the other 11, complete and awaiting delivery, were scrapped at Sydenham. The last surviving Seamew (XE180), which had been purchased by Shorts on 31 August 1959 for ground instruction at its Apprentice Training School, was scrapped in 1967.
The Rolls-Royce Heritage Trust has preserved a Seamew engine, which is found at its Coventry branch.
[edit] Operators
[edit] Specifications (Seamew AS.1)
General characteristics
- Crew: 2
- Payload: 1,844 lb (836 kg) of weapons
- Length: 41 ft (12.50 m)
- Wingspan: 55 ft (16.75 m)
- Wings folded 23 ft (7.01 m)
- Height: 13 ft 5in (4.09 m)
- Wings folded 15 ft 7.5 in (4.76 m)
- Wing area: 550 ft² (51 m²)
- Empty weight: 9,795 lb (4,443 kg)
- Loaded weight: 14,400 lb (6,804 kg)
- Max takeoff weight: 15,000 lb (6,790 kg)
- Powerplant: 1× Armstrong Siddeley Mamba turboprop engine, 1,590 shp (1,190 kW)
Performance
- Maximum speed: 236 mph (205 knots, 380 km/h)
- Range: 750 mi (650 nm, 1,200 km)
- Wing loading: 26 lb/ft² (127 kg/m²)
- Power/mass: 0.11 hp/lb (180 W/kg)
Armament
- Rockets: Several rockets carried underwing
- Bombs:
- 1× torpedo
- 4× depth charges
[edit] See also
Comparable aircraft
Related lists
[edit] References
[edit] Notes
[edit] Bibliography
- Green, Wiiliam and Pollinger, Gerald. The Observer's Book of Aircraft. London: Frederick Warne & Co. Ltd. 1956.
- Pearcy Arthur. "Short Seamew." Aviation News 6. 19 July 1990.
- Runciman, Squadron Leader W.J. Pilot's Flying Log Book. "Squadron Leader W.J. Runciman, A.F.C., D.F.M." Original held by his family, a copy held by P. Sortehaug, 4, William St., Dunedin, NZ.
- "The Seamew Calls a Halt to the Rising Cost of Air Power." Shorts Quarterly Review, Vol. 2, No. 3, Autumn 1953.
- The Short Seamew Light Anti-submarine Aircraft (promotional brochure). Belfast: Short Brothers and Harland Limited, c. 1953.
- Williams, Ray. Fly Navy: Aircraft of the Fleet Air Arm since 1945. London: Airlife Publishing, 1989, ISBN 1-85310-057-9.
- Winchester, Jim, ed. The World's Worst Aircraft: From Pioneering Failures to Multimillion Dollar Disasters. London: Amber Books Ltd., 2005. ISBN 1-904687-34-2.
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