From Wikipedia, the free encyclopedia

This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (November 2007)

Sunderland
Type	Military flying boat
Manufacturer	Short Brothers
Maiden flight	16 October 1937
Introduced	1938
Retired	1967
Primary users	RAF RAAF RNZAF French Naval Air Service (Aéronavale)
Variants	Short Sandringham Short Seaford

The S.25 Sunderland was a British flying boat patrol bomber developed for the Royal Air Force by Short Brothers, first flown on 16 October 1937 by Shorts' Chief Test Pilot, John Lankester Parker. Based in part upon the S.23 Empire flying boat, the flagship of Imperial Airways, the S.25 was extensively re-engineered for military service. As one of the most powerful and widely used flying boats throughout the Second World War, it terrorized the German U-boat fleet. It took its name from the town of Sunderland in northeast England.

Contents 1 Design and development 1.1 Basic design 1.1.1 Equipment and on-water management 1.1.2 Access and servicing 1.1.3 Beaching 1.1.4 Damage control 2 Variants 2.1 Prototype 2.2 Sunderland Mark I 2.3 Sunderland Mark II 2.4 Sunderland Mark III 2.5 Sunderland Mark IV (S.45 Seaford) 2.6 Sunderland Mark V 3 Operational history 3.1 World War II 3.1.1 2 June 1943 3.2 Post-War 4 Transport variants—Hythe and Sandringham 5 Military Operators 6 Commercial operators 7 Specifications (Sunderland III) 8 References 9 External links 10 Related content

The early 1930s saw intense competition in developing long-range flying boats for intercontinental passenger service. The United Kingdom had no match for the new American Sikorsky S-42 flying boats, which were making headlines all over the world. The powers-that-be in Britain felt that "something should be done".^{[citation needed]}

In 1934, the British Postmaster General declared that all first-class Royal Mail sent overseas was to travel by air, effectively establishing a subsidy for the development of intercontinental air transportation in a fashion similar to the U.S. domestic program a decade earlier. In response, Imperial Airways announced a competition between aircraft manufacturers to design and produce 28 flying boats, each weighing 18 tons (18.2 tonnes) and having a range of 700 miles (1,130 km) with a capacity for 24 passengers.

The contract went almost directly to Short Brothers of Rochester, England. Although Short had long built flying boats for the military and for Imperial Airways, none of them were in the class of size and sophistication requested, but the business opportunity was too great to pass up. Oswald Short, head of the company, began a fast-track program to come up with a design for a flying boat far beyond anything they had ever built.

While the first S.23 was under development, the British Air Ministry was taking actions that would result in a purely military version of the big Shorts flying boats. The 1933 Air Ministry requirement "R.2/33" called for a next-generation flying boat for ocean reconnaissance, in which the new aircraft had to have four engines but could be either a monoplane or biplane design.

The R.2/33 specification was released roughly in parallel with the Imperial Airways requirement, and while Shorts continued to develop the S.23, they also worked on a response to the Air Ministry's need at a lower priority. The military flying boat variant was designated S.25 and the design was submitted to the Air Ministry in 1934. Saunders-Roe also designed a flying boat, designated the "A.33", in response to the R.2/33 competition, and prototypes of both the S.25 and A.33 were ordered by the Ministry for evaluation.

The S.25 shared much in common with the S.23 but was most notably different in that it had a deeper hull profile. As with the S.23, the Sunderland's fuselage contained two decks with six bunks on the lower one, a galley with a twin kerosene pressure stove, a yacht-style porcelain flush toilet, an anchoring winch and a small machine shop for in-flight repairs. The crew was originally intended to be seven but increased in later versions to 11 or more.

It was of all-metal construction except for most of the control surfaces that were of fabric-covered metal-frame construction. Portable beaching gear could be attached by ground crew so that the aircraft could be pulled up on land (beached). The gear consisted of two 2-wheeled struts that could be attached to either side of the fuselage, below the wing, with a 2- or 4-wheel trolley and tow bar that could be attached under the rear of the hull.

The thick wings carried the four nacelle-mounted Bristol Pegasus XXII engines and accommodated six drum fuel tanks with a total capacity of 9,200 litres (2,025 Imperial gallons, 2,430 U.S. gallons). Four smaller fuel tanks were added later behind the rear wing spar to give a total fuel capacity of 11,602 litres (2,550 Imperial gallons, 3,037 U.S. gallons), enough for eight- to 14-hour patrols.

The specification called for an offensive armament of a 37 mm gun and up to 2,000 pounds (900 kg) of bombs, mines or (eventually) depth charges. The ordnance was stored inside the fuselage and was winched up to racks, under the wing centre-section, that could be traversed out through doors on each side of the (bomb room) fuselage above the waterline to their offensive position. Defensive armament included a Nash & Thomson FN-13 powered turret with four .303 Browning machine guns in the extreme tail and a manually operated .303 on either side of the fuselage, firing from ports just below and behind the wings.

Like all water-based aircraft there was a need to be able to navigate on water and to control the craft up to and at a mooring. In addition to the standard navigation lights there was also a de-mountable mooring mast that was positioned on the upper fuselage just aft of the astrodome hatch with a 360 degree white light to show that the aircraft was moored. The crew had to know the common marine signals for watercraft to ensure safety in busy waters.

The craft could be moored to a buoy by a pendant that attached to the keel under the forward fuselage. When the craft was off the buoy the forward end of the pendant was attached to the front of the hull just below the bomb-aimer's window. For anchoring there was a demountable bollard that fixed to the forward fuselage from where the front turret was retracted to allow an airman to man the position and pick up the buoy cage or to toss out the anchor.

A standard stocked-anchor was stowed in the forward compartment alongside the anchor winch. However, depending on the operating area, a number of different kinds of anchor might be carried to cope with, for example, coral, sand or rock anchorages.

For taxiing after landing, the galley hatches were used to extend sea drogues that could be used to turn the aircraft or maintain its across-wind progress (by deploying the drogue on one side only), or to slow the forward motion as much as possible (both deployed). When not in use the drogues were hand-hauled back inboard, folded and stowed in wall-mounted containers just below the hatches. Operation of the drogues could be a very dangerous exercise if the aircraft was travelling on the water at speed or in strong currents, because the approximately three-feet (one metre) diameter drogue would haul-up on its five-tonne attachment cable-end inside the galley very sharply and powerfully. Once deployed it was normally impossible to recover a drogue unless the aircraft was stationary relative to the local tidal flow.

Another means of direction control on the water was by application of the flight controls, rudder and ailerons. The ailerons would cause asymmetric drag from the airflow and, ultimately, drop a float into the water to cause drag on that wing. Otherwise the pilots could use variable engine power to control the direction and speed of the aircraft on the water. In adverse combinations of tide, wind and destination this could be very difficult. By the time a buoy approach was being made, up-wind and up-tide, the speed of advance could be brought to a stop by shutting down the inboard engines and blipping the magneto switches on the two outboard engines so that they were, effectively, idling at 250–350 rpm, instead of the 750–800 normally. Otherwise the best that could be done was to attack the mooring buoy with the minimum speed that allowed control of the aircraft and hope that the bow crewman could manage to grab the buoy cage going by and temporarily attach to the aircraft's bollard with a painter. A permanent attachment to the buoy's pendant was then quickly made after the aircraft was bought to a halt on its over-run and while it was being blown or washed back but before reaching the full extent of the mooring lines and the buoy's anchorage.

Crew and others usually entered the aircraft through the bow compartment door on the left forward side of the aircraft. Each of the compartments, from the front, were fitted with swash doors to maintain waterproof integrity of the compartment to about two-feet (600 mm) above normal water level. The doors could be opened for the less agile passengers but they were otherwise normally always kept closed. There were five doors from the front to aft separating the bow from the gun room, the ward room, the galley, the bomb room and the after compartments.

There was another external door in the tail compartment on the right side. This door was intended for boarding from a Braby (U-shaped) pontoon that was used where there was a full passenger-service mooring alongside a wharf or similar. This door could also be used to accept passengers or stretcher-bound patients when the aircraft was in the open water where the engines had to be kept running to maintain the aircraft's position for the approaching vessel.

Because the aircraft was kept facing into wind it was not very difficult for ambulatory passengers to stand on the gunwale of their boat and step up into the doorway when the boat was alongside. However, holding a small boat (such as a canoe or whaleboat) at right-angles to the aircraft, so that a stretcher could be supported at the far end while it was being fed in through the doorway to a crew member inside, was fraught with difficulty, particularly if the stretcher and occupant was wider than the doorway! Normally the stretcher occupant was most at risk, with the aircraft being the next most vulnerable from the bow of the boat.

Normal access to the upper parts of the aircraft was through the astrodome hatch at the front of the front spar of the wing centre-section, just at the rear of the navigator's station.

Bombs were loaded in through the bomb doors that formed the upper-half walls of the bomb room on both sides. The bomb racks were able to run in and out from the bomb room on tracks in the underside of the wing. Weapons were hoisted up to the extended racks that were run inboard and then were either lowered to stowages on the floor or prepared for use on the racks above. The doors were sprung-loaded to pop inwards from their frames and would fall under gravity so that the racks could run out through the space left in the top of the compartment. The doors could be released locally or remotely from the pilot's position during a bomb run. Normally the weapons were either bombs or depth charges and the racks were limited to a maximum of 1000 lb (500 kg) each. After the first salvo was dropped it was a race for the crew to get the next eight loaded before the pilot had the aircraft positioned on the next bombing run.

The fixed nose guns (introduced by the Australians) were demounted when the aircraft was waterborne and stowed in the gun room just aft of the bow compartment. The toilet was in the right half of this same compartment and stairs from the cockpit to the bow area divided the two.

Maintenance was performed on the engines by opening panels in the leading edge of the wing either side of the powerplant. A plank could be fitted across the front of the engine on the extensions of the open panels. A small manually-started auxiliary petrol-engine which was fitted into the leading edge of the right wing, powered a bilge and a fuel pump for clearing water and other fluids from the fuselage bilges and for refuelling.

In sheltered moorings or at sea, fuelling was accomplished by a powered or unpowered barge and with engine-driven or hand-powered pump(s). Where there were unreliable fuel supplies it might take a crew of 4 three to four hours to transfer 2,500 gallons (11,000 litres) of fuel into the aircraft. If the barge had a capacity of only about 800 gallons (as was usual) it could take three times that.

Airframe repairs were either effected from the inside or waited until the aircraft was in a sheltered mooring, or beached. One of the serious problems was that the heat-treated rivets in the hull plates were susceptible to corrosion after a long period in salt water. The heads would pop off and leaks would start into the bilges. The only resort was to haul the aircraft out onto the hard and replace them. Usually at the cost of many other heads coming off because of the riveting vibrations.

Most servicing personnel had tools modified to attach them to their person because dropping a tool normally meant it was gone forever. Glooped was the expression used.

The beaching gear was large and unwieldy. The main legs had to be ballasted to sink so that the leg could be raised upright into its housing under the wing centre-section, and then the lower part was pressed against the fuselage wall where it was pinned. This usually meant that two people would get wet through. The tail trolley was also ballasted to sink under the aft fuselage where the seagoing section of the hull ended. The upper arms of the trolley were raised to locate in mating holes in the exterior skin of the hull where the main weight of the aircraft would ultimately keep it in place; but until then it was precariously unstable.

Meanwhile a rope from the shore to the header buoy at the nose of the aircraft was threaded through the pulley on the buoy and attached to the aircraft's bollard. The shore end of this rope was managed by a person positioned at an electric capstan that would control the release of the aircraft from the buoy. A short rope connected the tail towing-eye in the fuselage to another hauling device, most often a tractor, that was able to manoeuvre the aircraft on the slipway and on the hardstanding beyond.

When all was ready the bowman cast off from the buoy pendant. The tail was pulled carefully to the slipway and the header buoy rope was paid out from the capstan off to the side. The idea was that the tail trolley should be bought into contact with the submerged section of the slipway as gently as possible, ensuring that the aircraft remained securely in place on the trolley as it started rolling up the slip. A sharp impact on the trolley wheels, located approximately five-feet (1.6 metres) below the keel, was enough to rotate the trolley around its fuselage attachment arms and dislodge it, allowing the aircraft's keel to strike the slip and thereby sustain damage.

When tidal flow or wind adversely affected the positioning of the aircraft, a situation could arise where the tail and attachments were running true, but the nose of the aircraft had now swung to one extreme of the slipway preventing the main wheels on one side from correctly contacting the slip. Consequently it is not surprising that Sunderlands were not beached for any minor reason.

Once the tail trolley was well up the slipway, a steering arm could be inserted into the lower part of the trolley and used to turn the wheels so that the assemblage could be guided to follow the tractor. Moving in the opposite direction was effected by a bridle attached to the front of the lower part of the main legs.

The aircraft was prevented from dipping either wingtip into the water by a large float mounted under each wing on two struts that were braced inboard and outboard by wires. With no wind, the float on the heavier side was always in the water. With some wind the ailerons could be used to balance the craft with both floats out of the water. In severe weather it was not unknown for a float to be wiped off completely or left just hanging; in which case, as the craft lost airspeed after landing, members of the crew ran out to the tip of the opposite wing to keep the serviceable float in the water while the aircraft was taxied to the mooring. Running out to the end of the wing in adverse weather was not an easy task, especially after a long patrol.

Aircraft with lower hull damage, from enemy action or otherwise, were patched or had the holes filled with any temporary materials before a landing was attempted and then it might be taxied immediately to the slipway and beached when its wheeled gear was attached, or it might be quickly beached on a sandy shore before it sank. More than two fuselage compartments had to be full of water to sink the aircraft so the damage had to be quite extensive or the distance to shore great.

Marine growths were a constant problem in some areas. The drag caused by long-standing growths could be enough to compromise the hull surface so that a fully loaded aircraft would be unable to gain enough speed to become airborne. The aircraft could be taken to a freshwater mooring for sufficient time to kill off the fauna and flora growing on the bottom which would then be washed away during takeoff runs. The alternative was to scrub it off, either in the water or on the hard. Neither was simple, especially in cold weather.

The takeoff run of a flying boat was often only dependent on the length of water that was available. The first problem was to gain sufficient speed for the craft to plane, otherwise there would never be enough speed to become airborne. Once planing, the next problem was to break free from the suction of the water on the hull. This was partly helped by the step in the hull just behind the craft's centre of buoyancy at planing speed. The pilot could rock the ship about this point to try to break the downward pull of the water on the surface of the hull. Somewhat rough water was a help in freeing the hull from the water, but on calm days it was often necessary to have a high-speed launch cross in front of the aircraft to cause a break in the water flow under the aircraft. It was a matter of judgement of the coxswain to get the crossing close enough but not too close. Because it was expected that some takeoffs would be protracted affairs, often the crews were not very careful to keep within maximum all-up weight limitations and getting airborne just took a little longer. In such cases the flight engineer would ignore the climbing cylinder-head temperatures and maintain the use of take-off power for more than five minutes at a time.

On Mk V aircraft, fuel could be dumped from retractable pipes that extended from the hull and were attached the bomb room side of the galley aft bulkhead. It was expected that dumping would be done while airborne, but it could also be done on the water, with care to ensure that the floating fuel went down-wind away from the aircraft.

The first S.25, now named the Sunderland Mark I, flew from the River Medway on 16 October 1937. The deeper hull and installation of nose and tail turrets gave the Sunderland a considerably different appearance from the Empire flying boats. The prototype was fitted with Bristol Pegasus X engines, each providing 709 kW (950 hp), as the planned Pegasus XXII engines of 753 kW (1,010 hp) were not available at the time.

The 37 mm gun, originally intended as a primary anti-submarine weapon, was dropped from the plans during the prototype phase and replaced with a Nash & Thomson FN-11 nose turret mounting a single 0.303 inch (7.7 mm) Vickers GO machine gun. The turret could be winched back into the nose, revealing a small "deck" and de-mountable marine bollard used during mooring manoeuvres on the water. The change of armament in the nose to the much lighter gun moved the centre of gravity rearwards.

After the first flight, the aircraft was returned to the workshop and a modified wing was installed with a 4.5° sweep to the rear, thereby moving the centre of pressure into a more reasonable position in relation to the new centre of gravity. This left the engines and wing floats canted out from the aircraft's centreline. Although the wing loading was much higher than that of any previous RAF flying boat, a new flap system kept the take-off run to a reasonable length, and the aircraft first flew with the new wing and the uprated Pegasus XXII engines on 7 March 1938.

Official enthusiasm for the type was so great that in March 1936, before the first flight of the prototype, the Air Ministry had ordered 21 production examples.

Meanwhile, delivery of the Saro A33 was delayed and it did not fly until October 1938. The aircraft was written off after it suffered a structural failure during high-speed taxi trials and no other prototypes were built.

The RAF received its first Sunderland Mark I in June 1938 when the second production aircraft was flown to Singapore. By the outbreak of war in Europe, in September 1939, RAF Coastal Command was operating 40 Sunderlands.

Beginning in October 1941, Sunderlands were fitted with ASV Mark II radar (Air to Surface Vessel). This was a primitive low-frequency radar system operating at a wavelength of 1.5 m, featuring a row of four prominent "stickleback" yagi antennas on top of the rear fuselage, two rows of four smaller aerials on either side of the fuselage beneath the stickleback antennas, and a single receiving aerial mounted under each wing outboard of the float and angled outward.

A total of 75 Sunderland Mark I's were built: 60 at Shorts' factories at Rochester, England and Belfast, Northern Ireland, and 15 by Blackburn Aircraft at Dumbarton.

In August 1941, production moved to the Sunderland Mark II that featured Pegasus XVIII engines with two-speed superchargers, providing 794 kW (1,065 hp) each.

The tail turret was changed to an FN.4A turret that retained the four .303 (7.7 mm) guns of its predecessor but provided twice the ammunition capacity with 1,000 rounds per gun. Late production Mark IIs also had a FN.7 dorsal turret, mounted offset to the right just behind the wings and fitted with twin .303 (7.7 mm) machine guns. The hand-held guns behind the wing were removed in these versions.

Only 43 Mark IIs were built, with five manufactured by Blackburn.

Production quickly went on in December 1941 to the Sunderland Mark III, which featured a revised hull configuration as tested on a Mark I the previous June. This modification improved seaworthiness, which had suffered as the weight of the Sunderland increased with new marks and field changes. In earlier Sunderlands, the hull "step" that allows a flying boat to "unstick" from the surface of the sea was an abrupt one, but in the Mk III it was a curve upwards from the forward-hull line.

The Mark III turned out to be the definitive Sunderland variant, with 461 built. Most were built by Shorts at Rochester and Belfast, a further 35 at a new (but temporary)^[1] Shorts plant at White Cross Bay, Lake Windermere;^[2][3] while 170 were built by Blackburn Aircraft. The Sunderland Mark III proved to be one of the RAF Coastal Command's major weapons against the U-boats, along with the Consolidated PBY Catalina.

The Sunderland Mark IV was an outgrowth of the 1942 Air Ministry Specification R.8/42, for a generally improved Sunderland with more powerful Bristol Hercules engines, better defensive armament and other enhancements. The new Sunderland was intended for service in the Pacific. Although initially developed and two prototypes built as the "Sunderland Mark IV" it was different enough from the Sunderland line to be given a different name.

Relative to the Mark III, the Mark IV had a stronger wing, larger tailplanes and a longer fuselage with some changes in form for better performance in the water. The armament was heavier with .50 inch (12.7 mm) machine guns and 20 mm Hispano cannon.

The changes were so substantial that the new aircraft was redesignated the Short Seaford. Thirty production examples were ordered; the first delivered too late to see combat and only eight production Seafords were completed and never got beyond operational trials with the RAF.

The next production version was the Sunderland Mark V, which evolved out of crew concerns over the lack of power of the Pegasus engines. The weight creep (partly due to the addition of radar) that afflicted the Sunderland had resulted in running the Pegasus engines at combat power as a normal procedure and the overburdened engines had to be replaced regularly.

Australian Sunderland crews suggested that the Pegasus engines be replaced by Pratt & Whitney R-1830-9OB Twin Wasp engines. The 14-cylinder engines provided 895 kW (1,200 hp) each and were in use on RAF Consolidated Catalinas and Douglas Dakotas, making logistics and maintenance straightforward.

Two Mark IIIs were taken off the production lines in early 1944 and fitted with the American engines. Trials were conducted in early 1944 and the conversion proved all that was expected. The new engines (and propellors) provided greater performance with no real penalty in range. In particular, a Twin Wasp Sunderland could stay airborne if two engines were knocked out on the same wing while, in similar circumstances, a standard Mark III would steadily lose altitude.

Production was switched to the Twin Wasp version and the first Mark V reached operational units in February 1945. Defensive armament fits were similar to those of the Mark III, but the Mark V was equipped with new centimetric ASV Mark VI C radar that had been used on some of the last production Mark IIIs as well.

One hundred and fifty-five Sunderland Mark Vs were built and another 33 Mark IIIs were converted to Mark V specification. With the end of the war, large contracts for the Sunderland were cancelled and the last of these great flying boats was delivered in June 1946, with a total production of 749 aircraft.

During the Second World War, although British anti-submarine efforts were disorganized and ineffectual at first, Sunderlands quickly proved useful in the rescue of the crews from torpedoed ships. On 21 September 1939, two Sunderlands rescued the entire 34-man crew of the torpedoed merchantman Kensington Court from the North Sea. As British anti-submarine measures improved the Sunderland began to show its claws as well. A Royal Australian Air Force (RAAF) Sunderland performed the type's first unassisted kill of a U-boat on 17 July 1940.

As aircrew honed their combat skills, the Sunderland Mark I received various improvements to make it more effective. The nose turret was upgraded to two .303 (7.7 mm) guns instead of one, and new propellers together with pneumatic rubber wing de-icing boots were also fitted.

Although the .303 guns lacked range and hitting power, the Sunderland had a fair number of them and it was a well-built machine that was hard to destroy. On 3 April 1940, a Sunderland operating off Norway was attacked by six German Junkers Ju 88 medium bombers and managed to shoot one down, damage another enough to send it off to a forced landing, and drove off the rest. The Germans are reported to have nicknamed the Sunderland the "Fliegendes Stachelschwein" (Flying Porcupine) due to its defensive firepower and to the several prominent antennas protruding from it.

Sunderlands also proved themselves in the Mediterranean theatre. They performed valiantly in evacuations during the German seizure of Crete, carrying a surprising number of passengers, and one performed the reconnaissance mission to observe the Italian fleet at anchor in Taranto before the famous Royal Navy Fleet Air Arm's torpedo attack on 11 November 1940; the Battle of Taranto.

New weapons made the flying boats more deadly in combat. In 1939, one 100 lb anti-submarine bomb hit HMS Snapper merely breaking its light bulbs whilst other bombs had reportedly bounced up and hit their launch aircraft. In early 1943 these ineffective weapons were replaced by Torpex depth charges that would sink to a predetermined depth and then explode. This eliminated the problem of bounce-back, and the shock wave propagating through the water augmented the explosive effect.

While the bright Leigh searchlight was rarely fitted to Sunderlands, ASV Mark II radar allowed the flying boats to effectively target U-boats operating on the surface. In response, the German submarines began to carry a radar warning system known as "Metox", also known as the Cross of Biscay due to the appearance of its receiving antenna that was tuned to the ASV frequency and gave the submarines early warning that an aircraft was in the area.

Kills fell off drastically until ASV Mark III radar was introduced in early 1943, which operated in the centimetric band and used antennas mounted in blisters under the wings outboard of the floats, instead of the cluttered stickleback aerials. Sunderland Mark IIIs fitted with ASV Mark III were designated Sunderland Mark IIIAs.

Centimetric radar was invisible to Metox and completely baffled the Germans at first. Admiral Karl Dönitz, commander of the German U-boat force, suspected that the British were being informed of submarine movements by spies. In August 1943, a captured RAF airman misled the Germans by telling them that the aircraft were homing on the signals radiated by the Metox,^[4][5] and consequently U-boat commanders were instructed to turn them off.

In any case, the Germans responded by fitting U-boats with one or two 37 mm and twin quad 20 mm flak guns to shoot it out with the attackers. While Sunderlands could suppress flak to an extent by hosing down the U-boat with their nose-turret guns, the U-boats had the edge by far in range and hitting power. To help improve the odds, the Australians first fitted their aircraft in the field with an additional four .303s in fixed mounts in the nose, allowing the pilot to add fire while diving on the submarine before bomb release. Most aircraft were similarly modified. The addition of single .50 calibre (12.7 mm) flexibly-mounted M2 Browning machine guns in the (previously emptied) beam hatches behind and above the wing trailing edge also became common.

The rifle-calibre .303 guns lacked hitting power, but the Sunderland retained its reputation for being able to take care of itself. This reputation was enhanced by an air battle between eight Ju 88C long-range heavy fighters and a single RAAF Sunderland Mark III of No. 461 Squadron RAAF on 2 June 1943. This battle was one of several stories of the type's operations related by author Ivan Southall, who flew in Sunderlands during the war.^[6] There were 11 crewmen on board the Sunderland; nine Australians and two British.^[7] The crew was on an anti-submarine patrol and also searching for remains of BOAC Flight 777, an airliner that had left Lisbon the day before and subsequently had been shot down over the Bay of Biscay.

In the late afternoon, one of the crew spotted the eight Ju 88s. Bombs and depth charges were dumped while the pilot, Flt. Lt. Colin Walker, "redlined" the engines. Two Ju 88s made passes at the flying boat, one from each side, scoring hits and managing to disable one engine while the Sunderland went through wild "corkscrew" evasive manoeuvres. On the third pass of the fighters, the dorsal turret gunner managed to shoot one down. Another Ju 88 disabled the tail turret, but the next fighter that made a pass was hit by the dorsal and nose turrets and was shot down as well.

Still another fighter attacked, destroying the Sunderland's radio gear, wounding most of the crew in varying degrees and mortally wounding one of the side gunners (Flight Sergeant "Ted" Miles). A Ju 88 tried to attack from the rear but the tail turret gunner had managed to regain some control over the turret and shot it down. The surviving fighters continued to attack, but the nose gunner damaged one of these, setting its engines on fire. Two more of the attackers were also hit and the final pair disengaged and departed. Luftwaffe records indicate that the latter were the only two that made it back to base.

The Sunderland was heavily damaged. The crew threw everything they could overboard and nursed the aircraft back to the Cornish coast, where Walker managed to land and beach it at Praa Sands. The crew waded ashore, carrying their dead comrade, while the surf broke the Sunderland up. Walker received the Distinguished Service Order and several of the other crew-members also received medals.

Walker went on to a ground job while the rest of the crew was given a new Sunderland. That Sunderland and its crew disappeared without a trace over the Bay of Biscay two months later after reporting by radio that they were under attack by six Ju 88s.

At the end of the Second World War, a number of new Sunderlands built at Belfast were simply taken out to sea and scuttled as there was nothing else to do with them. Despite this indignity, there was plenty of life left in the Sunderland. In Europe it was removed from service relatively quickly; however, in the Far East, where well-developed runways were less common and large land-based maritime patrol aircraft like the new Avro Shackleton could not be used so easily, there was still a need for it, and it remained in service with the Far East Air Force at Singapore until 1959, and with the Royal New Zealand Air Force's No. 5 Squadron RNZAF and No. 6 Squadron RNZAF until 1967. A preserved RNZAF Sunderland is exhibited at the Museum of Transport and Technology, Auckland.

During the Berlin Airlift (which lasted from June 1948 until August 1949) ten Sunderlands and two Hythes were used to transport goods—especially salt— from Finkenwerder on the Elbe near Hamburg to the isolated city, landing on the Havelsee lake beside RAF Gatow until it iced over.^[8] This is the only known operational use of flying boats within central Europe.

The French Aéronavale Escadrille 7FE, which received Sunderlands when it was formed in 1943 as No. 343 Squadron RAF, continued to operate them until December 1960, the last unit to operate Sunderlands in the Northern Hemisphere.^[9]

RAF Sunderlands also saw service in the Korean War with No. 209 Squadron RAF,^[10] and with the Royal New Zealand Air Force until the mid-1960s.^[11]

In late 1942, the British Overseas Airways Corporation (BOAC) obtained six Sunderland Mark IIIs and modified them for service as mail carriers to Nigeria and India, with primitive accommodation for seven passengers. Armament was removed, with gun positions being faired over, and simple seating fitted in place of the bunks. As such they were operated by BOAC and the RAF jointly from Poole to Lagos and Calcutta. Minor modifications to the engine angles and flight angle resulted in a significant increase in the cruise speed, which was a relatively unimportant issue for the combat Sunderlands. In the immediate post-war period, locally modified ex-RNZAF Mark IIIs were used by New Zealand's National Airways Corporation to link South Pacific Islands in the Coral Route before TEAL Short Sandringhams took over after 1947.

BOAC obtained more Mark IIIs and gradually came up with better accommodation for 24 passengers, including sleeping berths for 16. These conversions were given the name Hythe and BOAC operated 29 of them by the end of the war.

A more polished civilian conversion of the Sunderland was completed by the manufacturer as the postwar Short Sandringham. The Sandringham Mark I used Pegasus engines while the Sandringham Mark II used Twin Wasp engines.

 Australia

Royal Australian Air Force

No. 10 Squadron RAAF

No. 40 Squadron RAAF

No. 461 Squadron RAAF

 Canada

Royal Canadian Air Force

No. 422 Squadron RCAF

No. 423 Squadron RCAF

No. 461 Squadron RCAF

 France

French Navy

No. 343 Squadron RAF, later Escadrille 7FE^[12]

Flottille 1FE

Flottille 7F

Flottille 27F

Escadrilles 12S

Escadrilles 50S

Escadrilles 53S

 New Zealand

Royal New Zealand Air Force

No. 5 Squadron RNZAF

No. 6 Squadron RNZAF

No. 490 Squadron RNZAF

 Norway

Norwegian Air Force

No. 330 Squadron RAF

 Portugal

Portuguese Navy

Naval Aviation

 South Africa

South African Air Force

No. 35 Squadron SAAF

 United Kingdom

Royal Air Force

• Aerolineas Argentinas.
• Ansett Flying Boat Services flew the Sunderland and its Sandringham variant from Rose Bay on Sydney Harbour to Lord Howe Island until 10 September 1974^[13]
• Aquila Airways.
• BOAC.
• CAUSA.
• Dodero.
• DNL.
• National Airways Corporation of New Zealand.
• Qantas.
• TEAL.
• Trans Oceanic Airways.

Data from Jane's Fighting Aircraft of World War II^[14]

General characteristics

• Crew: 8—11 (two pilots, radio operator, navigator, engineer, bomb-aimer, three to five gunners)
• Length: 85 ft 4 in (26.0 m)
• Wingspan: 112 ft 9½ in (34.39 m)
• Height: 32 ft 10½ in (10 m)
• Wing area: 1,487 ft² (138 m²)
• Empty weight: 34,500 lb (15,663 kg)
• Loaded weight: 58,000 lb (26,332 kg)
• Powerplant: 4× Bristol Pegasus XVIII nine-cylinder radial engines, 1,065 hp (794 kW) each

Performance

• Maximum speed: 210 mph (336 km/h) at 6,500 ft (1,980 m)
• Cruise speed: 178 mph (285 km/h) at 5,000 ft (1,525 m)
• Stall speed: 78 mph (125 km/h)
• Range: 1,780 mi (2,848 km)
• Service ceiling: 16,000 ft (4,880 m)
• Rate of climb: 720 ft/min (3.67 m/s)
• Wing loading: 39 lb/ft² (191 kg/m²)
• Power/mass: .018 hp/lb (.030 kW/kg)

Armament

• 8× 0.303 inch (7.7 mm) Browning machine guns
• various munitions, including bombs and depth charges, carried internally and winched out beneath the wings

Notes

Bibliography

• Fighting the U-boats: Short Sunderland
• Short Sunderland
• Video of static preserved exhibit at IWM Duxford: http://www.youtube.com/watch?v=pIG5xFUQpgI

Comparable aircraft

• Kawanishi H8K
• PBM Mariner
• PB2M Mars
• PB2Y Coronado
• Saro Lerwick

Designation sequence

S.17 Kent - S.18 Knuckleduster - S.19 Singapore III - S.20 Mercury - S.21 Maia - S.22 Scion Senior - S.23 C Class Empire - S.25 Sunderland - S.25V Sandringham - S.26 G Class Empire - S.29 Stirling - S.35 & S.40 Shetland - S.44 Sealand - S.45 Seaford - S.45A Solent

Related lists

List of aircraft of the RAF

See also

• RAF Gatow

v • d • e Lists relating to aviation
General	Timeline of aviation · Aircraft · Aircraft manufacturers · Aircraft engines · Aircraft engine manufacturers · Airports · Airlines
Military	Air forces · Aircraft weapons · Missiles · Unmanned aerial vehicles (UAVs) · Experimental aircraft
Notable incidents and accidents	Military aviation · Airliners · General aviation · Famous aviation-related deaths
Records	Flight airspeed record · Flight distance record · Flight altitude record · Flight endurance record · Most produced aircraft