Short Sunderland flying boat patrol bomber

The Short Sunderland flying boat, designed and built by Belfast-based aircraft manufacturer Short Brothers, was a military development of the 'C'-class Empire flying boat operated by Imperial Airways.  The Sunderland's fuselage was of all-metal, stressed skin construction, with fabric covering the rudder, ailerons, and elevators.  Entering service in June 1938, the Sunderland proved so successful that it remained in front line service for over 20 years.  The Sunderland was the first British flying boat to have power-operated gun turrets as part of its defensive armament and with its 12-16 guns, the aircraft earned the nickname 'The Flying Porcupine' from German Luftwaffe pilots that encountered it.  In addition to the RAF, the Sunderland would be operated by the Royal Canadian Air Force, Royal Australian Air Force, Royal New Zealand Air Force, South African Air Force, French Navy, Norwegian Air Force, and Portuguese Navy.

Three RAF squadrons were equipped with Sunderlands by the time war broke out in September 1939 and eventually a total of 749 Sunderlands would be built.  The aircraft carried a crew of 14 so that they could work in shifts during anti-submarine and reconnaissance patrols lasting 12 hours or more in defence of the convoys on which Britain relied.  The first unassisted submarine kill by a Sunderland occurred on 17 July 1940 by an aircraft of No. 10 Squadron of the Royal Australian Air Force.  Sunderlands were also used in the Mediterranean theatre, where they played an important role in evacuating troops during the Battle of Crete in May 1941, being capable of carrying 82 men and their weapons.  In a search and rescue capacity, Sunderlands were responsible for saving the lives of many airmen shot down over the sea and sailors whose ships had been torpedoed.  The final operational mission by a Sunderland assigned to RAF Coastal Command was carried out in June 1945, more than four weeks after the German surrender, and Sunderlands continued to operate from bases in Africa and the Far East.  With the end of the war in August 1945, all contracts for new Sunderlands were cancelled and dozens of recently-completed Sunderlands were packed with new, but now surplus, military equipment and deliberately sunk.    

In the post-war period, Sunderlands took part in the Berlin Airlift in 1948-49, ferrying 4,847 tons of freight to help keep West Berlin supplied following the Soviet blockage; this included loads of salt, of which each corrosion-proofed Sunderland, could carry 10,020 pounds (4,550 kilograms).  During the Korean War, Sunderlands based in Japan carried out almost 900 operational sorties, totalling over 13,350 flying hours.  While the Sunderland was retired from service in Europe fairly soon after the end of the Second World War, it continued to be used in the Far East, which lacked the large, developed airfields capable of accommodating the new land-based maritime patrol aircraft then entering service.  The Sunderland was the last type of flying boat operated by the RAF, and the last Sunderland, serving with the RAF's Far East Air Force based at Seletar, Singapore, was retired and scrapped in May 1959.  The Royal New Zealand Air Force continued to fly the Sunderland until 1967.

Specifications: Short Sunderland Mk V flying boat
Type: Long-range general reconnaissance and anti-submarine patrol flying boat
In service: 1944-1959
Engines: 4 x 1,200-horsepower Pratt & Whitney R-1830-90 Twin Wasp air-cooled radial piston engines
Maximum speed: 343 km/h (213 mph) at 1,520 metres (5,000 feet)
Maximum altitude: 5,370 metres (17,900 feet)
Wingspan: 34.34 metres (112 feet 8 inches)
Length: 26 metres (85 feet 4 inches)
Loaded weight: 27,200 kilograms (60,000 pounds)
Armament: 4 x Browning .303-inch (7.7mm) machine guns in tail turret; 2 x Browning .303-inch machine guns in nose turret; 4 x fixed, remote-controlled .303-inch machine guns in nose; 2 x 0.5-inch (12.7mm) beam machine guns; 2,000 pounds (908 kilograms) of bombs or four/eight depth charges for anti-submarine work on racks in the hull

A Short Sunderland Mk V, registration ML824, on display at the Royal Air Force Museum London, 22 September 2015.  ML824 was built as a Sunderland Mk III by Short Brothers in Belfast in June 1944 and converted to Mk V configuration the following month.  Delivered to the Royal Air Force on 6 November 1944, ML824 joined No. 201 Squadron in Northern Ireland on 11 February 1945, conducting 10 anti-submarine patrols and one convoy patrol.  On 17 April 1945, ML824 was transferred to No.330 (Norwegian) Squadron at Sullom Voe in the Shetland Islands.  

A view of ML824 showing two of the aircraft's four Pratt & Whitney R-1830 Twin Wasp engines, which were installed in August 1949.  After a period in storage in the late 1940s, ML824 was reconditioned by Short Brothers and included in a batch of 14 Sunderlands transferred to the French Navy in 1951 under the auspices of the Western Union Defence Programme.  The French Navy operated ML824 out of Dakar, Senegal until late 1960, when the aircraft was redeployed to France.  In March 1961, France gifted ML824 to the Short Sunderland Trust and later in the month the aircraft was flown to Pembroke Dock in Wales and put on public display from 2 June 1962.

The Sunderland's nose turret was able to slide backward to permit crewmen to access the mooring compartment, in which one of the mannequins is standing.  The mooring compartment contained an anchor, winch, ladder, and boat-hook used by the air gunners to secure the aircraft to a buoy after landing.  Each mooring position was marked by a rubber buoy anchored to the seabed and specially designed so as not to damage the Sunderland's bow if the two made contact.  Although the mooring procedure was relatively simple in calm, fair weather, it was far more tricky, dangerous, and wet when attempted at night in an exposed, bleak harbour in winter weather conditions.  On 11 January 1971, ML824 was formally transferred to the Royal Air Force Museum and was partially dismantled for transport to the museum's site in North London.  After a period in storage, ML824 was reassembled and placed on display outside the museum in October 1976.  In 1978, ML824 was moved into the museum's new Battle of Britain hall and, between 1993 and 1995, work was undertaken to permit public access to the aircraft's lower deck.

As a flying boat, the Sunderland could not be fitted with a traditional bomb bay in its belly.  Instead, bombs, mines, or depth charges could be launched from track-mounted racks located under the centre-section of the wing.  The Sunderland could carry up to 2,000 pounds (910 kilograms) of these munitions internally, either in the bomb room or lower down in the fuselage.  The munitions were winched up and hung on the overhead bomb racks and a hatch on each side of the fuselage was opened inwards to permit the motorised racks to be run out on the tracks under the wings.  After the weapons were dropped, the racks were brought back inside the fuselage for reloading.

A mannequin depicting a Leading Aircraftman stands on one of the fold-down engine-servicing platforms built into the leading edge of the Sunderland's wing to permit access to the engines via the inspection panels.  Although Mk III Sunderlands were originally fitted with four Bristol Pegasus XVIII 9-cylinder air-cooled radial piston engines, each generating 1,065 horsepower, the increased weight of the Mk V Sunderlands led to the adoption of more powerful 1,200-horsepower Pratt & Whitney R-1830 Twin Wasp engines.  Maintenance on the Sunderlands was always done while afloat, with the aircraft only brought ashore for major overhauls.  When heavily loaded, the Sunderland could not remain airborne on only three engines and would be forced to land, often with catastrophic results for both the aircraft and its crew.  

A mannequin portrays the rear turret air gunner on the catwalk in the fuselage, carefully making his way forward and stretching out for handholds as the aircraft pitches and rolls on the water beneath him.  A heavy flight suit with fur-lined collar, fur-lined boots, and thick leather gloves helped protect crewmen against the cold in the unheated Sunderland.

A view of the starboard side of Sunderland ML824, resting on a steel cradle in one of the exhibition halls of the Royal Air Force Museum London.  The large floats under each wing helped maintain stability on the water, with the float on the heavier side of the aircraft always in the water.  If not regularly cleaned, marine growth on the underside of the Sunderland's hull could create sufficient drag to prevent the aircraft from gaining enough speed to become airborne.  To haul the Sunderland onto land, the aircraft was taxied to a slipway where wheeled beaching gear was fitted and the aircraft pulled out of the water.

Painted with the squadron code letters 'NS Z' of No. 201 Squadron, Royal Air Force, ML824 is seen here on 4 May 2022.  ML824 remains in the same spot it occupied prior to the extensive renovations of this hall (formerly the Battle of Britain hall) from late 2016 to its re-opening on 30 June 2018.  The mannequins seen in 2015 have been removed, other artefacts previously displayed next to the aircraft have been relocated, lower intensity lighting has been installed on the hall's ceiling, and visitors can explore the length of ML824's lower deck fuselage interior.

Entering at the rear of ML824's fuselage, visitors proceed along a narrow catwalk toward the nose.  A short ladder on the left (not accessible to visitors) leads to the upper deck and the cockpit.  Large square hatches on the aircraft's port and starboard sides above and behind the wing trailing edge previously accommodated half-inch (12.7mm), flexibly-mounted M2 Browning machine guns.

A view from inside ML824's bomb room, showing four 250-pound (110 kilogram) hydrostatically-fused Mk XI aerial depth charges slung on the track-mounted rails which run from inside the fuselage out along the underside of the wings.  During an attack, the bombs, depth charges, or mines could be released either locally from the bomb room or remotely from the pilot's position.  

Given the Sunderland's endurance of around 13 hours when cruising at 155 knots (286 km/h; 178 mph) and an altitude of 5,000 feet (1,500 metres), the aircraft had a small galley fitted with a twin kerosene pressure stove (on the right) and a small sink for washing up.  This allowed the crew to brew hot drinks and cook meals during the long, usually monotonous anti-submarine patrols over the North Atlantic.  The Sunderland also had a porcelain flush toilet and even a small onboard machine shop for performing inflight repairs. 

The lower deck crew rest space, which featured six bunks.

The bow compartment of the Sunderland housed the bomb aimer's position.  The bomb aimer would lay in a prone position, using the window at the front to spot the target and determine the right moment to drop the aircraft's load of bombs or depth charges.  In Mk V Sunderlands, the bow compartment also housed the four fixed, remote-controlled .303-inch Browning machine guns used to counter fire from German U-boats and other enemy vessels as the Sunderland dived toward its bomb release position.  Fed by belts of ammunition contained in the boxes mounted on the floor, these guns were controlled from the pilot's position.  The fixed nose guns, introduced when in Australian service, were removed when the Sunderland was on the water and stowed in the gun room just aft of the bow compartment.  The bow compartment also housed the aircraft's toilet, with stairs from the cockpit separating the two.   

A Short Sunderland Mk V, registration ML796, as seen on display in the AirSpace gallery of the Imperial War Museum Duxford in Cambridgeshire on 28 October 2017.  The bulge under the starboard wing (to the left of the float) housed the ASV III air-surface vessel radar fitted on Mk V Sunderlands).  ML796 was built by Short Brothers as a Mk III and was subsequently converted to Mk V standard.  Delivered to the Royal Air Force on 15 May 1945, ML 796 served with a number of squadrons and operational training units and, in 1948, took part in the Berlin Airlift as part of No. 230 Squadron.  As part of a batch of 14 Sunderlands transferred to the French Navy, ML796 was overhauled in 1950 and transferred to the French at Dakar, Senegal in 1951.  ML796 operated out of Dakar until December 1960 and then out of Toulon until 30 January 1962.

A closer look at the forward fuselage of ML796, including the cockpit and nose gunner position.  Following its service with the French Navy, ML796 was flown to France and placed in storage for five years until purchased for use as a disco at Maisden-le-Riviere.  It was subsequently moved to La Baule in Brittany and used as a nightclub and restaurant.  The Imperial War Museum Duxford acquired ML796 for free in the mid-1970s and shipped it to the museum in five pieces, arriving there on 9 July 1976.