Supermarine Sea Otter
|Prototype of Sea Otter|
|First flight||23 September 1938|
|Primary users||Royal Air Force|
Royal Danish Air Force
|Developed from||Supermarine Walrus|
The Supermarine Sea Otter was a British amphibious aircraft designed and built by Supermarine; it was a longer-range development of the Walrus and was the last biplane flying boat to be designed by Supermarine; it was also the last biplane to enter service with the Royal Navy and the RAF.
Design and development
The main difference between the Walrus and the Sea Otter was in the mounting of the powerplant; the Walrus had a rear-facing engine with a pusher propeller and the Sea Otter's engine faced forward with a tractor propeller.
There was considerable development of the power plant/propeller combination during the design of the Sea Otter, which at its conception was called the "Stingray". The original test aircraft had a Bristol Perseus XI radial engine with a two-bladed propeller, which gave insufficient thrust so a two-position three-blade propeller was substituted, later changed again to a four-bladed type with the pairs of blades set at an angle of 35°, instead of the usual 90°. The first flight took place on 23 September 1938, but it was not until January 1942 that the Air Ministry placed a production order. Due to cooling troubles found with the Perseus, the power-plant was changed for production aircraft to the Bristol Mercury XXX engine driving a three-bladed propeller. The Sea Otter was used by both the RAF and the Royal Navy for air-sea rescue and patrol roles.
Postwar, Sea Otters were converted for civilian use. The cabin was soundproofed and fitted with heating. Seating for four passengers, a chemical toilet and a stowage for baggage were provided. As they were intended for use as Bush airplanes in remote areas, versatility was important. To allow cargo to be carried, the cabin floor was strengthened and fitted with lashing points, and the passenger seats made easily removable.
Of the 592 aircraft ordered, only 292 were built due to the end of the Second World War. Eight aircraft were bought for the Royal Danish Air Force, and another eight were supplied to the Dutch Naval Air Arm. The colonial service of France purchased six Sea Otters for use in French Indochina.
- Sea Otter Mk I
- Reconnaissance and communications amphibian aircraft.
- Sea Otter Mk II
- Air Sea Rescue amphibian aircraft.
- Royal Netherlands Navy
- Royal Air Force
- Royal Navy
- 700 Naval Air Squadron
- 712 Naval Air Squadron
- 716 Naval Air Squadron
- 721 Naval Air Squadron
- 723 Naval Air Squadron
- 728 Naval Air Squadron
- 729 Naval Air Squadron
- 733 Naval Air Squadron
- 740 Naval Air Squadron
- 742 Naval Air Squadron
- 744 Naval Air Squadron
- 771 Naval Air Squadron
- 772 Naval Air Squadron
- 778 Naval Air Squadron
- 781 Naval Air Squadron
- 799 Naval Air Squadron
- 810 Naval Air Squadron
- 1700 Naval Air Squadron
- 1701 Naval Air Squadron
- 1702 Naval Air Squadron
- 1703 Naval Air Squadron
Specifications (Sea Otter)
- Crew: 3-4
- Length: 39 ft 9 in (12.12 m) in rigging position
- Wingspan: 46 ft 0 in (14.02 m)
- Width: 18 ft 0 in (5.49 m) folded
- Height: 16 ft 2 in (4.93 m) with one propeller blade vertically downwards in the rigging position
- Wing area: 610 sq ft (57 m2)
- Empty weight: 6,805 lb (3,087 kg) amphibian
- 6,475 lb (2,937 kg) flying boat
- Gross weight: 10,000 lb (4,536 kg)
- Fuel capacity: 162 imp gal (195 US gal; 740 l) in two upper wing root tanks ; 11 imp gal (13 US gal; 50 l) oil
- 206 imp gal (247 US gal; 940 l) maximum fuel capacity as a flying boat
- Powerplant: 1 × Bristol Mercury XXX 9-cylinder air-cooled radial piston engine, 805 hp (600 kW) for take-off
- 855 hp (638 kW) maximum at 4,500 ft (1,372 m)
- 740 hp (552 kW) maximum continuous at 5,000 ft (1,524 m)
- Propellers: 3-bladed Rotol, 11 ft 3 in (3.43 m) diameter constant-speed propeller
- Maximum speed: 163 mph (262 km/h, 142 kn) at 4,500 ft (1,372 m)
- Cruise speed: 100 mph (160 km/h, 87 kn) at 5,000 ft (1,524 m)
- Range: 565–725 mi (909–1,167 km, 491–630 nmi)
- Ferry range: 920 mi (1,480 km, 800 nmi) with auxiliary overload tank
- Service ceiling: 17,000 ft (5,200 m)
- Rate of climb: 870 ft/min (4.4 m/s)
- Time to altitude: at 5,000 ft (1,524 m) in 6 minutes 12 seconds
- Wing loading: 15.1 lb/sq ft (74 kg/m2)
- Power/mass: 0.0877 hp/lb (0.1442 kW/kg)
- Take-off distance to 50 ft (15 m): 1,665 ft (507 m) from land
- Take-off time from water: 24 seconds
- Guns: 1 × .303 in (7.7 mm) Vickers K machine gun in nose and 2 aft
- Bombs: 4 × 250 lb (110 kg) bombs
No museum holds a complete aircraft. The Fleet Air Arm Museum (Australia) at Nowra, New South Wales, Australia, has the nose section of JN200, a Sea Otter which served with the Royal Australian Navy.
Aircraft of comparable role, configuration, and era
- List of aircraft of World War II
- List of aircraft of the Fleet Air Arm
- List of aircraft of the Royal Air Force
- "Civil Sea Otter". Flight: 383–384. 10 October 1946.
- Halley 1980, p. 354.
- Sturtivant and Ballance 1994, p.363.
- Bridgman, Leonard, ed. (1947). Jane's All the World's Aircraft 1947 (35th ed.). London: Sampson Low, Marston & Co. pp. 84c–85c.
- Andrews and Morgan 1987, p. 162.
- Lambert, Roger. "RAN Sea Otter Dataplate" (PDF). www.adf-serials.com. Retrieved 16 May 2013.
- Andrews, C.F. Supermarine Aircraft Since 1914. London: Putnam, 1981. ISBN 0-370-10018-2.
- Andrews, C.F. Supermarine Aircraft Since 1914. London: Putnam, Second edition, 1987. ISBN 0-85177-800-3.
- Halley, James J. The Squadrons of the Royal Air Force. Tonbridge, Kent, UK: Air Britain (Historians) Ltd., 1980. ISBN 0-85130-083-9.
- Sturtivant, Ray and Theo Ballance. The Squadrons of the Fleet Air Arm. Tonbridge, Kent, UK: Air Britain (Historians) Ltd., 1994. ISBN 0-85130-223-8.
- Media related to Supermarine Sea Otter at Wikimedia Commons