Short Seamew

The Short SB.6 Seamew was a 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 with the Reserve branch of the service. It first flew on 23 August 1953, but, due to poor performance coupled with shifting defence doctrine, it never reached service and only 24 production aircraft had flown before the project was cancelled. It has been described as a "camel amongst race-horses".


Short Seamew
Class Aircraft
Type Attack
Manufacturer Short Brothers
Origin United Kingdom - UK (Great Britain)
Country Name Origin Year
United Kingdom - UK (Great Britain) 1953
Country Name Operational Year Retirement Year
United Kingdom - UK (Great Britain) 1953 1957 View
ManufacturerName Production From Production To Quantity
Short Brothers 26 View

The pilot and observer were located in tandem cockpits located high up in the front of the deep, narrow fuselage, creating a decidedly "curious" profile. 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 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 so that the pilot could be sat directly over it with the absence of a piston engine ignition system which would have interfered with the radar scanner mounted below the engine housing.

For simplicity, and so that a nosewheel would not obscure the forward field of the radar scanner, a fixed tailwheel undercarriage was used. The long stroke necessary on the main undercarriage to allow for heavy deck landings while giving the radar scanner and propeller adequate clearance from the ground resulted in an alarming attitude on the ground and the cockpits mounted at a seemingly perilous height. For landing the tailwheel extended so it could land at a more level attitude.

The pilot and observer sat very far forward in order for the pilot to 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 spotting surface vessels 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 tailplane 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.

The weapons bay was 14 ft long and 3 ft wide. By omitting the rotating radar scanner it could be extended to 17 ft in order to carry longer weapons.

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."

The stall speed of the Seamew was 50 knots and it required only 50% of engine power to maintain flight. Runciman said "take off and landing are simple and straightforward", "it is, in fact, impossible to bounce the Seamew", and that its performance in crosswinds was "outstanding".

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[8] with three of them converted to AS1 standard; the fourth (XE175) was flown by S/L W. "Wally" J. Runciman for a series of sales tours in 1956 to Italy (March), Yugoslavia (April) and West Germany (May).

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.

Role Anti-submarine aircraft
Manufacturer Short Brothers
First flight 23 August 1953
Retired 1957
Primary users Royal Navy Fleet Air Arm
Royal Naval Volunteer Reserve
Number built 26


General characteristics

  • Crew: two
  • Payload: 1,844 lb (836 kg) of weapons
  • Length: 41 ft (12.50 m)
  • Wingspan: 55 ft (16.76 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 (6,532 kg)
  • Max. takeoff weight: 15,000 lb (6,804 kg)
  • Powerplant: 1 × Armstrong Siddeley Mamba turboprop, 1,590 shp (1,195 kW)
  • Propellers: Rotol four-bladed propeller
  • Propeller diameter: 10 ft (3.05 m)

Performance

  • Maximum speed: 236 mph (205 knots, 380 km/h)
  • Range: 750 mi (650 nmi, 1,207 km)
  • Endurance: 4 hours at 120 kn at 5,000 ft
  • Rate of climb: 1,600 ft/min initial
  • Wing loading: 26 lb/ft² (127 kg/m²)
  • Power/mass: 0.11 hp/lb (180 W/kg)
  • Take off: 500 ft at 60.7 kn tas into 12 kn wind

Armament

  • Rockets: Several rockets carried underwing
  • Sonobuoys: 20 28-lb
  • Bombs:
    1× torpedo
    4× depth charges
    275-lb A/S bombs

End notes