Supermarine Type 304

Supermarine Aviation Works

Company type	Company
Industry	Aerospace, Aircraft manufacturing
Founded	1920s in Woolston, Southampton, United Kingdom
Fate	Became part of Vickers-Armstrongs
Headquarters	Woolston, Southampton , United Kingdom
Area served	Worldwide
Key people	R. J. Mitchell (designer)
Products	Aircraft, including Supermarine Stranraer flying boat
Owner	Vickers-Armstrongs (parent company)
Parent	Vickers-Armstrongs

The Supermarine Stranraer was a British flying boat developed and manufactured by Supermarine Aviation Works, located in Woolston, Southampton. Created during the 1930s primarily for the Royal Air Force (RAF), it represented the RAF's final and fastest biplane flying boat model.

Evolving from the earlier Supermarine Scapa, its design was largely influenced by the Air Ministry's Specification R.24/31 issued in 1931. Although initially turned down by the Air Ministry, Supermarine carried on refining the project as a private venture under the name Southampton V. A contract for a prototype was awarded in 1933, coinciding with the aircraft being named after the Scottish town of Stranraer. The prototype's maiden flight occurred on 24 July 1934, and by 1937, the Stranraer had been introduced into active RAF service. The majority of these aircraft were operational at the start of World War II.

During the early war years, Stranraers primarily performed convoy escort and anti-submarine patrol missions. By March 1941, they were withdrawn from frontline duty but remained in use for training until October 1942. Apart from British production, Canadian Vickers in Montreal manufactured 40 units under licence for the Royal Canadian Air Force (RCAF). These Canadian-built Stranraers operated in anti-submarine and coastal defence roles along both Atlantic and Pacific Canadian coastlines until their retirement in 1946. After military service ended, many former RCAF aircraft were sold to emerging regional airlines, where they continued to serve as passenger and cargo planes throughout the 1950s.

Background

Supermarine's factory at Woolston, Southampton

The Supermarine Stranraer was a direct successor to the Supermarine Scapa, marking the last flying boat designed by R. J. Mitchell for the RAF. Manufactured at Supermarine’s Woolston facility, production deliveries spanned from 1937 to 1939. Development began in the early 1930s under Mitchell’s leadership.

This project originated in response to Specification R.24/31 issued by the Air Ministry in 1931, which called for a general-purpose coastal reconnaissance flying boat capable of carrying a payload approximately 1,000 pounds (450 kg) heavier than that of its predecessor, the Scapa, and able to sustain level flight on one engine—capabilities that the Scapa lacked. Supermarine’s initial submission was an enlarged version of the Scapa competing against Saunders-Roe’s design.

Although Saunders-Roe’s proposal was preferred by the Air Ministry and Supermarine’s design was rejected, Supermarine decided to continue development independently as a private venture under the designation Southampton V.

Prototypes and production

In 1933, an order was placed for a single prototype equipped with two Bristol Pegasus IIIM engines, each delivering 820 horsepower, and the aircraft was designated the Stranraer. The first prototype, bearing the serial K3973, took to the skies for its inaugural flight on 24 July 1934, with Joseph Summers serving as pilot. During the subsequent months, an intensive initial flight testing phase was undertaken. By 24 October 1934, the prototype was handed over to the Marine Aircraft Experimental Establishment (MAEE) at RAF Felixstowe for official evaluation trials.

Following successful proving flights, the Air Ministry placed a preliminary order on 29 August 1935 for 17 units (serial numbers K7287 to K7303) to meet Specification 17/35. In May 1936, an additional order for six aircraft (serials K9676 to K9681) was issued but later cancelled. The first production-standard Stranraer completed its maiden flight in December 1936 and officially entered RAF service on 16 April 1937. The last of these flying boats was delivered on 3 April 1939. Furthermore, Canadian Vickers Limited produced 40 Stranraers under licence in Canada; both Supermarine and Canadian Vickers operated as subsidiaries of Vickers-Armstrongs.

Description

A 1935 cigarette card illustrating the Supermarine Stranraer

The Stranraer was a twin-engine biplane flying boat designed to accommodate a crew of six to seven members. It had an empty weight of approximately 11,250 pounds and could reach a maximum takeoff weight of around 19,000 pounds.

Evolving from the earlier Scapa model, the Stranraer featured a two-bay wing configuration. Its wingspan and surface area were increased by about 12 percent compared to its predecessor, while the elevator size grew by roughly 7 percent. The rudders were equipped with trim tabs to maintain directional stability during single-engine operation. Power was supplied by moderately supercharged Bristol Pegasus IIIM radial engines. The airframe construction primarily utilized alclad material, complemented by stainless steel fittings; metal parts were anodised to prevent corrosion. Additional structural integrity was achieved through the inclusion of a second pair of interplane struts. The hull's cross-sectional area expanded by approximately 18 percent without compromising hydrodynamic efficiency. Modifications included a retractable forward gun mount, a lowered midship gunner’s station, and a newly added tail gunner position located just aft of the control surfaces, featuring a hooded windshield. These design enhancements were informed by operational experience gained from earlier Southampton flying boats.

The production variant differed from the prototype mainly through the installation of more powerful Pegasus X engines rated at 920 horsepower. Engine nacelles were mounted beneath the upper wing to keep propellers clear of sea spray. Fuel storage comprised two petrol tanks of 250 imperial gallons each situated within the upper wing’s center section; fuel delivery relied on gravity feed supplemented by fuel pumps.

The initial two-bladed wooden propellers used on prototypes were replaced in production models by three-bladed Fairey-Reed metal propellers. Wing structure revisions resulted in a two-bay configuration.

Armament consisted of three .303-inch Lewis guns positioned in nose, dorsal, and tail locations. Additionally, the aircraft could carry bomb loads up to 1,000 pounds.

Pre-September 1939 military service

The Stranraer, alongside its contemporary the Saro London, represented the final generation of multi-engine biplane flying boats to be operated by the RAF. The RAF introduced 17 Stranraers starting in 1937, though they were already regarded as outdated upon entering service. The aircraft were ordered in August 1935, coinciding with the renaming to Stranraer. Prior to the outbreak of war, these flying boats were primarily assigned to No. 228 Squadron, No. 209 Squadron, and No. 240 Squadron. Pilot feedback was generally unfavorable, with many considering the aircraft's performance marginal at best. Nevertheless, some acknowledged that its seaworthiness surpassed that of several contemporaries, including the Consolidated PBY Catalina. By 1938, certain Stranraer-equipped squadrons had begun transitioning to newer types such as the Short Sunderland and Short Singapore flying boats.

Early in its operational tenure, the Stranraer undertook several demanding long-range flights; notably, a single exercise in September 1938 involved a journey covering approximately 4,000 miles (6,400 km).

RAF Stranraers SOC ("struck off charge") before September 1939

Serial	Delivered	Fate	Notes
K3973	October 1934	SOC (30 October 1938)	Prototype rendered obsolete
K7288	September 1937	Crashed into sea during night exercise, caught fire and sank (28 March 1938)	Six fatalities
K7297	September 1938	Lost over the North Sea (19 August 1939)	Six fatalities

World War II operations

During World War II, no Stranraers were deployed beyond UK territorial waters. Immediately after hostilities commenced in September 1939, these aircraft conducted patrols over the North Sea, monitoring enemy maritime traffic between Scotland and Norway. Typical armament for such missions included bombs under one wing and an auxiliary fuel tank on the opposite side. Stranraer patrol duties concluded on 17 March 1941. They served notably with No. 240 Squadron and were also present in limited numbers at the No. 4 (Coastal) Operational Training Unit. The last RAF Stranraer sortie was flown by K7303 from Felixstowe on 30 October 1942.

RCAF Stranraer sporting wartime camouflage

The aircraft earned a reputation among crews that was often less than flattering, acquiring numerous mocking nicknames throughout its service. One such moniker was "whistling shithouse," derived from its toilet design which opened directly to the outside air; when raised, airflow caused a distinctive whistling noise. Other sobriquets included "Flying Meccano Set," "The Marpole Bridge," "Seymour Seine Net," "Strainer," "Flying Centre Section of the Lion's Gate Bridge," as well as a more polite variant, "Whistling Birdcage."

In Canadian service, RCAF Stranraers were identical to their British counterparts and primarily utilized for coastal anti-submarine patrols similar to those performed by the RAF units. Aviation historian Dirk Septer noted that no combat engagements involving RCAF Stranraers were recorded. However, a notable incident involved a crew from 5 Squadron, led by Flight Lieutenant Leonard Birchall, who captured an Italian merchant vessel named Capo Nola in the Gulf of Saint Lawrence shortly after Canada declared war on Italy on 10 June 1940. Birchall had been tasked with locating Italian ships in Canadian waters as hostilities loomed; upon spotting Capo Nola, he executed a low pass mimicking an attack run, prompting the ship’s captain to ground the vessel on a sandbank. Birchall then landed nearby and awaited Royal Canadian Navy support. The crew of Capo Nola became the first Italian prisoners held by Allied forces during the conflict. The Canadian-built Vickers Stranraers remained operational with the RCAF throughout the war, with the final example retired on 20 January 1946.

RAF Stranraers SOC or destroyed between 1939 and 1942

Serial	Delivered	Fate	Notes
K7287	April 1937	SOC (25 June 1941)
K7289	December 1937	Unknown status after June 1941
K7290	January 1938	Sank during gale (21 November 1940)
K7291	June 1938	Collided with light boat and sank (10 November 1940)
K7292	February 1938	SOC (13 May 1941)
K7293	March 1938	Lost in gale (17 February 1941)
K7294	May 1938	Damaged beyond repair after water impact (3 November 1939)
K7295	July 1938	Written off after water impact (4 September 1942)
K7296	August 1938	SOC (22 September 1939)
K7298	September 1938	Crashed into sea (12 June 1941)	Nine fatalities
K7299	October 1938	SOC (4 April 1941)
K7300	November 1938	Sank in gale (20 October 1941)
K7301	December 1938	Sank in gale (21 August 1940)
K7302	January 1939	Sank in gale (20 October 1941)
K7303	April 1939	SOC (31 October 1942)

Civilian use

Beginning in May 1935, the Stranraer was adapted for civilian applications, evolving into the Type 237. Approximately half of the 40 RCAF Stranraers remained sufficiently intact after the war to be considered for further use. Out of these, 13 units were sold to civilian buyers via Crown Assets following the conclusion of hostilities, with registrations issued in both Canada and the United States. Several were upgraded to the Super Stranraer variant, featuring more powerful 1,200 horsepower (890 kW) Wright GR-1820-G202GA engines replacing their original Pegasus powerplants.

Post-World War II, a number of these aircraft operated with Queen Charlotte Airlines (QCA) in British Columbia, continuing service until 1958. QCA, at one point ranked as Canada’s third-largest airline, was colloquially dubbed the Queer Collection of Aircraft due to its eclectic fleet assembled from various surplus types. Within QCA’s fleet, the Stranraer earned a reputation as a well-suited aircraft and was reportedly "well liked" by its flight crews. Additionally, eight surplus Stranraers were purchased by Aero Transport Ltd., based in Tampa, Florida.

Military

Canada

Supermarine Stranraer 912 of the RCAF at RCAF Station Jericho Beach

• RCAF – Squadrons within the Home War Establishment (HWE) stationed in Canada
  • Eastern Air Command
    • No. 5 Squadron RCAF Operated Supermarine Stranraers from November 1938 to September 1941
    • No. 117 Squadron RCAF Utilized Supermarine Stranraers between September and October 1941
  • Western Air Command
    • No. 4 Squadron RCAF Employed Supermarine Stranraers from July 1939 to September 1943
    • No. 6 Squadron RCAF Used Supermarine Stranraers from November 1941 through May 1943
    • No. 7 Squadron RCAF Operated Supermarine Stranraers between February 1943 and March 1944
    • No. 9 Squadron RCAF Flew Supermarine Stranraers from December 1941 to April 1943
    • No. 13 (OT) Squadron RCAF Utilized Supermarine Stranraers between October 1941 and November 1942
    • No. 120 Squadron RCAF Operated Supermarine Stranraers from November 1941 until October 1943
    • (OT) - Operational Training units;

United Kingdom

A Mark I Stranraer from No. 240 Squadron RAF landing on Loch Ryan

• Royal Air Force
  • No. 201 Squadron RAF
  • No. 209 Squadron RAF
  • No. 210 Squadron RAF
  • No. 228 Squadron RAF
  • No. 240 Squadron RAF

Civilian

United States

• Aero Transport Ltd.

Canada

• Pacific Western Airlines
• Queen Charlotte Airlines
• Wardair

Specifications

{{Aircraft specs |ref= Supermarine Aircraft since 1914, Database: Supermarine Stranraer |prime units?= imp |crew= 6 to 7 |length ft= 54 |length in= 9 |length note= |span ft= 85 |span in= 0 |span note= |height ft= 21 |height in= 9 |height note= |wing area sqft= 1,457 |wing area note= |aspect ratio= |airfoil= |empty weight lb= 11,250 |empty weight note= |gross weight lb= 19,000 |gross weight note= |max takeoff weight lb= |max takeoff weight note= |fuel capacity= |more general= |eng1 number= 2 |eng1 name= Bristol Pegasus X |eng1 type= nine-cylinder air-cooled radial piston engines |eng1 hp= 920 |prop blade number= 3 |prop name= variable-pitch metal propellers |prop dia ft= |prop dia in= |prop dia note= |max speed mph= 165 |max speed note= at 6,000 ft (1,800 m)

• Landing speed: 58.5 mph (50.8 kn; 94.1 km/h)

|cruise speed mph= 105 |cruise speed note= |stall speed mph= |stall speed note= |never exceed speed mph= |never exceed speed note= |min control speed mph= |min control speed note= |range miles= 1,000 |range note= at 105 mph (91 kn; 169 km/h) and 5,000 ft (1,500 m) |combat range miles= |combat range note= |ferry range miles= |ferry range note= |endurance= |ceiling ft= 18,500 |ceiling note= |g limits= |roll rate= |climb rate ftmin= 1,350 |climb rate note= |time to altitude= 10,000 ft (3,000 m) in 10 minutes |wing loading lb/sqft= 13 |wing loading note= |fuel consumption lb/mi= |power/mass= 0.097 hp/lb (0.159 kW/kg) |} Armament:

• Three × 0.303 British (0.303 in (7.70 mm)) Lewis gun machine guns
• Up to 1,000 lb (454 kg) of bombs or depth charges on external racks beneath the main wings
• Eight × 20 lb (9 kg) bombs stored internally within bays located in the lower mainplanes

Surviving aircraft

The sole remaining Supermarine Stranraer, exhibited at the RAF Museum London, 2021

Only one Stranraer remains intact today: serial number 920/CF-BXO, which is part of the collection at the Royal Air Force Museum London. Manufactured in 1940 by Canadian Vickers as one of forty units built, this aircraft served with the Royal Canadian Air Force (RCAF). It was employed across multiple squadrons for anti-submarine missions, crew training, and passenger transport. Following its military service, it was retired in 1944 and subsequently operated by the civilian airline Canadian Pacific Airlines until 1947. Later, Queen Charlotte Airlines acquired the aircraft and replaced its original powerplants with American Wright R-1820 Cyclone engines. The airline utilized it for passenger flights along the British Columbia Pacific coastline until 1952. Afterward, it passed through several private owners until sustaining damage from a ship collision in 1966. The Royal Air Force Museum purchased the aircraft in 1970 and transported it back to the United Kingdom.

A second Stranraer, serial number 915/CF-BYJ, exists only as parts held by the Shearwater Aviation Museum at CFB Shearwater, Halifax, Nova Scotia, Canada. This aircraft also flew with Queen Charlotte Airlines before crashing on December 24, 1949, near Belize Inlet, British Columbia. Initial components were recovered during the 1980s; additional wreckage was brought to the museum in November 2008 for restoration efforts—excluding the forward fuselage and cockpit sections. As of 2025, these parts remain stored awaiting restoration.

See also

• Short Knuckleduster

Sources

• Andrews, C. F.; Morgan, Eric B. (1981). Supermarine Aircraft since 1914. London: Putnam. ISBN 978-03701-0-018-0.
• Bowyer, Michael J.F. (1991). Aircraft for the Few: the RAF's fighters and bombers in 1940. Sparkford, UK: Patrick Stephens Ltd. ISBN 978-1-85260-040-2.
• Kostenuk, S.; Griffin, J. (1977). RCAF Squadron Histories and Aircraft: 1924–1968. Toronto: Samuel Stevens, Hakkert & Company. ISBN 978-0-88866-577-5.
• London, Peter (2003). British Flying Boats. Stroud, UK: Sutton Publishing. ISBN 978-0-7509-2695-9.
• March, Daniel J. (2000). British Warplanes of World War II. Hoo (Rochester), UK: Aerospace Publishing Ltd. ISBN 1-84013-391-0.
• Morgan, Eric (April 2001). "Database: Supermarine Stranraer". Aeroplane. No. 235. Stamford, UK: Key Publishing. pp. 53–65.
• Oliver, David (2003). Wings over Water: a chronicle of the flying boats and amphibians of the twentieth century. London: Quantum. ISBN 978-08628-8-559-5.
• "Operational Requirements" (PDF). Aeromilitaria. No. 4. Air Britain. 1996. pp. 87–106. ISSN 0262-8791.
• Pegram, Ralph (2016). Beyond the Spitfire: The Unseen Designs of R.J. Mitchell. Cheltenham, UK: The History Press. ISBN 978-0-7509-6515-6.
• Petrescu, Relly Victoria; Petrescu, Florian Ion (2013). The Aviation History: New Aircraft I - Color. Norderstedt: GmbH. ISBN 978-38482-6-639-5.
• Pigott, Peter (2003). Taming the Skies: A Celebration of Canadian Flight. Toronto; Oxford: Dundurn. ISBN 978-1-55002-469-2.
• Robertson, Bruce (1967). British Military Aircraft Serials 1912–1966. London: Ian Allan ltd. OCLC 6400372.
• Septer, Dirk (April 2001). ""Canada's Stranraers"". Aeroplane. No. 235. Stamford, UK: Key Publishing.
• Thetford, Owen (1979). "Aircraft of the Royal Air Force since 1918". London: Putnam. ISBN 978-03703-0-186-0.

Additional resources

• Kightly, James; Wallsgrove, Roger. Supermarine Walrus & Stranraer. Mushroom Model Publications, 2004. Published in Sandomierz, Poland and Redbourn, UK. ISBN 978-83-917178-9-9.

External links

• Royal Canadian Air Force: Supermarine Stranraer