Seaplane, Part IV

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 (of No. 10 Squadron) made 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. The nose turret was upgraded with a second .303 (7.7 mm) gun. 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. It shot one down, damaged 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.

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. One flew 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.

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-filled depth charges that would sink to a determined 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 enabled the flying boats to attack U-boats 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 antennae 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 called Sunderland Mark IIIAs. Centimetric radar was invisible to Metox and 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 in on the signals radiated by the Metox, 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 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 inch (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 Junkers Ju 88C long range heavy fighters and a single RAAF Sunderland Mark III of No. 461 Squadron RAAF on 2 June 1943. This was one of several stories of the type's operations related by author Ivan Southall, who flew in Sunderlands during the war. There were 11 crewmen on board the Sunderland; nine Australians and two British. The aircraft 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 had subsequently been shot down over the Bay of Biscay, killing actor Leslie Howard. In the late afternoon, one of the crew spotted the eight Ju 88s. Bombs and depth charges were dumped and the engines "redlined".

Two Ju 88s made passes at the flying boat, one from each side, scoring hits and disabling one engine while the Sunderland went through wild "corkscrew" evasive manoeuvres. On the third pass, the dorsal turret gunner shot one down. Another Ju 88 disabled the tail turret, but the next one that made a pass was hit by both the dorsal and nose turrets and shot down. Another destroyed the Sunderland's radio gear, wounding most of the crew to varying degrees and mortally wounding one of the side gunners. A Ju 88 tried to attack from the rear, but the tail turret gunner had regained some control over the turret and shot it down.

The surviving Ju 88s 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, the only two to make it back to base. The Sunderland had been heavily damaged. The crew threw everything they could overboard and nursed the aircraft back to the Cornish coast, where pilot Colin 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. With the exception of Walker, the crew returned to Sunderlands - they disappeared without trace over the Bay of Biscay two months later after reporting 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. In Europe it was removed from service relatively quickly but 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 RAF 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.

During the Berlin Airlift (June 1948 - August 1949) 10 Sunderlands and two Hythes were used to transport goods from Finkenwerder on the Elbe near Hamburg to the isolated city, landing on the Havelsee lake beside RAF Gatow until it iced over. This is the only known operational use of flying boats within central Europe. The Sunderlands were particularly used for transporting salt, as their airframes were already protected against corrosion from seawater. Transporting salt in standard aircraft risked rapid and severe structural corrosion in the event of a spillage. When the Havelsee did freeze over the Sunderland's role was taken by freight-converted Handley Page Halifaxes with salt being carried in panniers fitted under the fuselage to avoid the corrosion problem.

From mid-1950, RAF Sunderlands also saw service during the Korean War initially with No. 88 Squadron but shortly followed by Nos. 205 and 209 Squadrons. The three squadrons shared the operational task equally with rotational detachments of three or four aircraft and crews based at Iwakuni, Japan. Missions lasting 10 to 13 hours were flown daily throughout the war, and also during the Armistice period that followed, until September 1954. The Sunderland also saw service with the Royal New Zealand Air Force until 1967.

The French Navy 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.

The first S.25, now named the Sunderland Mark I, flew from the River Medway on 16 October 1937 with Shorts' Chief Test Pilot, John Lankester Parker at the controls. 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 950 hp (709 kW ), as the planned Pegasus XXII engines of 1,010 hp (753 kW) 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 .303 inch (7.7 mm) Vickers GO machine gun.

The turret could be winched back into the nose, revealing a small "deck" and demountable 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 series of flights the aircraft was returned to the workshop and the wing was swept 4.25° 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 Royal Air Force flying boat, a new flap system kept the takeoff run to a reasonable length and the aircraft first flew with the new wing sweep and the uprated Pegasus XXII engines on 7 March 1938.

Official enthusiasm for the type had been so great that in March 1936, well before the first flight of the prototype, the Air Ministry ordered 21 production examples. Meanwhile, delivery of the other contender Saro A.33 was delayed and it did not fly until October 1938. The aircraft was written off after it suffered 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 (L2159) was flown to 230 Squadron at RAF Seletar, Singapore. By the outbreak of war in Europe, in September 1939, RAF Coastal Command was operating 40 Sunderlands.

The main offensive load was up to 2,000 lb (910 kg) of bombs (usually 250 or 500 lb), mines (1,000 lb) or other stores that were hung on traversing racks under the wing centre section (to and from the bomb room in the fuselage).

Later, depth charges (usually 250 lb) were added. By late 1940 two Vickers K machine guns had been added to new hatches that were inserted into the upper sides of the fuselage just aft of the wing, with appropriate slipstream deflectors. A second gun was added to the nose turret. New constant speed propellers and deicing boots were installed as well during 1940.

As the defensive weaponry improved the aircraft became a formidable foe, even though it was far from base, travelled fairly slowly (120 knots and down to about 90 kt for long range cruise) and was usually at low altitude. But a Sunderland off Norway on 3 April 1940 was attacked by six Junkers Ju 88 with the result that one was shot down, one forced to immediately land and the others went home, much wiser.

Later, over the Bay of Biscay eight Ju 88 attacked one Sunderland escorting a convoy and three were shot down by the patrol aircraft.

A Sunderland made the vital reconnaissance of Taranto before the Royal Navy Fleet Air Arm's attack on the Italian navy there on 11 November 1940.

The aircraft was not a great success at landing and taking off from rough water, but, other than in the open sea, it could be handled onto and off a short chop, by a skilled pilot. Many rescues were made, early in the war, of crews that were in the Channel having abandoned or ditched their aircraft, or abandoned their ship.

In May 1941, during the Battle of Crete Sunderlands transported as many as 82 armed men from place to place in one load. Steep ocean swells were never attempted, however a calm ocean could be suitable for landing and takeoff.

Beginning in October 1941, Sunderlands were fitted with ASV Mark II "Air to Surface Vessel" radar . This was a primitive low frequency radar system operating at a wavelength of 1.5 m. It used 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 were built: 60 at Shorts' factories at Rochester and Belfast, Northern Ireland, and 15 by Blackburn Aircraft at Dumbarton.

The RAF allocated the AP1566 series of air publications to the Sunderland.

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

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

Only 43 Mark IIs were built, five of these by Blackburn.

Production quickly went on in December 1941 to the Sunderland Mark III which featured a revised hull configuration which had been 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) Shorts plant at White Cross Bay, Lake Windermere; 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 Catalina.

As the U-boats began to use Metox passive receivers the ASV Mk II radar gave away the presence of aircraft and the number of sightings diminished drastically. The RAF response was to upgrade to the ASV Mk III, which operated in the 50 cm band, with antennas that could be faired into fewer more streamlined blisters. During the Mk III's life there were a large number of almost continuous improvements made, including the ASV Mk IIIA and four more machine guns in a fixed position in the wall of the forward fuselage just behind the turret (developed on RAAF aircraft first) with a simple bead and ring sight for the pilot.

 

Despite the 14-hour-long patrols expected of their crews, early Sunderland gunners were provided with only 500 rounds of ammunition each. Later 1,000 round ammunition boxes were installed in the turrets. The beam hatch guns were removed from Mk II aircraft but Mk IIIs and then Mk Is gained much more capable .5 guns, one each side.

Offensive weapons loads increased too. The introduction of the hydrostatically fused 250 lb (110 kg) depth charge meant that additional weapons could be carried on the floor of the bomb room in wooden restraints, along with ammunition boxes of 10 and 25 lb anti-personnel bombs that could be hand launched from various hatches to harass U-boat crews otherwise manning the twin 37 and dual quadruple 20 mm cannons that U-boats were fitted with.

As radar detection became more effective there were more night patrols to catch U-boats on the surface charging their batteries. Attacking in the dark was a problem that was solved by carrying one inch (25.4 mm), electrically initiated flares and dropping then out of the rear chute of the aircraft as it got close to the surface vessel. Sunderlands never carried Leigh lights, probably because the flares were sufficient.

By this time the crew workload had increased so much that it needed at least 10 to crew the aircraft. During attacks they were sorely pressed to get all of the necessary work done and crews took many shortcuts that possibly proved fatal in some cases.

In early 1944 the ordnance load in the aircraft and the long length of patrols, meaning maximum fuel loads, required that much more powerful engines were needed. It was decided to fit 1,200 hp (890 kW) P&W R1830-90B, Twin Wasp, powerplants. These were commonly available and maintenance crews on Catalina, Liberator and Dakota aircraft were familiar with them. This led to the production of the Mk V aircraft.

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, the S.45 "Seaford".

Relative to the Mark III, the Mark IV had a stronger wing, larger tailplanes and a longer fuselage with some changes in hull 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 R183090B Twin Wasp engines. The 14-cylinder engines provided 1,200 hp (895 kW) each and were already in use on RAF Consolidated Catalinas and Douglas Dakotas, and so logistics and maintenance were 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 with new 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.

A total of 155 Sunderland Mark Vs were built with another 33 Mark IIIs converted to Mark V specification. With the end of the war, large contracts for the Sunderland were cancelled and the last of these flying boats was delivered in June 1946, with a total production of 749 aircraft completed.

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, the 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 late 1944, the Royal New Zealand Air Force acquired four new Sunderland Mk IIIs already configured for transport duties. In the immediate postwar period, these 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. In February 1946 the first of these, G-AGJM, made a 35,313 mile route survey from Poole to Australia, New Zealand, Hong Kong, Shanghai and Tokyo in 206 flying hours. It was the first British civil flying boat to visit China and Japan.

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

 

The Supermarine Sea Otter was a British amphibian 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.

The main difference between the Walrus and the Sea Otter was in the mounting of the power plant. The Walrus had a rear-facing engine with a pusher propeller. 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 concept was called the "Stingray". The original test aircraft had a Bristol Perseus XI radial engine with a two-bladed propeller. This gave insufficient thrust so a two-position three blade was tried. This was 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 airscrew. The Sea Otter was used by both the RAF and the Royal Navy for air-sea rescue (ASR) and patrol roles.

Post-war, 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 Indo-China.

The Supermarine Stranraer was a 1930s British flying boat designed and built by Supermarine Aviation Works which marked the end of biplane flying-boat development for the Royal Air Force. They entered operations in 1937 and many were still in service at the outbreak of the Second World War undertaking anti-submarine and convoy escort patrols. They were withdrawn from operational service in March 1941 but continued to serve in a training capacity until October 1942.

Designed by R. J. Mitchell as a tender to Air Ministry R.24/31 Specification for a coastal reconnaissance flying boat for the RAF, it was initially turned down but Supermarine proceeded with the type as a private venture first known as the Southampton V. A contract was placed in 1933 for a prototype powered by two 820 hp (611 kW) Bristol Pegasus IIIM and the type became known as the Stranraer.

The structure was mainly duralumin, with the hull covered with sheet metal and the wings with fabric.

Following the initial flight-test programme, the Stranraer prototype (K3973) on 24 October 1934 was delivered to the RAF. On 29 August 1935, an initial order was placed for 17 aircraft (serial numbers K7287 to K7303) to the Air Ministry Specification 17/35. The production version was fitted with the 920 hp (686 kW) Pegasus X and first flew in December 1936, entering service operations on 16 April 1937; the last Stranraer was delivered 3 April 1939.

An additional order for six aircraft (K9676 to K9681) was placed in May 1936, but subsequently cancelled. A total of 40 Stranraers were built in Canada by Canadian Vickers Limited; Supermarine and Canadian Vickers being subsidiaries of Vickers-Armstrongs.

In service, only 17 Stranraers were operated by the RAF 1937-1941 primarily by No. 228, No, 209, No. 240 Squadrons along with limited numbers at the No. 4 OTU. Generally, the aircraft was not well-received as its performance was considered marginal.

Due to its less than favourable reception by flight and ground crews, the Stranraer gained a large number of derisive nicknames. It was sometimes referred to as a "whistling shithouse" because the toilet opened out directly to the air and when the seat was lifted, the airflow caused the toilet to whistle.

The Stranraer also acquired "Flying Meccano Set," "The Marpole Bridge," "Seymour Seine Net," "Strainer," "Flying Centre Section of the Lion's Gate Bridge" as well as a more genteel variant of its usual nickname, "Whistling Birdcage."

Royal Canadian Air Force Stranraers were exact equivalents of their RAF counterparts and while they were employed in coastal patrol against submarine threats in a similar role to the British Stranraers, no enemy action was recorded.

The Canadian Vickers-built Stranraers served with the RCAF until 1946. 13 examples were sold through Crown Assets (Canadian government) and passed into civilian use after the war, several serving with Queen Charlotte Airlines (QCA) in British Columbia and operated until 1957. A re-engine project by the airline substituted 1,000 hp (746 kW) Wright GR-1820-G202GA engines in place of the original Pegasus units.

In QCA use, the Stranraer gained a more suitable reputation and was "well liked" by its crews. A total of eight surplus Stranraers were also sold to Aero Transport Ltd. of Tampa, Florida.

A single intact Stranraer, 920/CF-BXO, survives in the collection of the Royal Air Force Museum London.

This aircraft was built in 1940, one of 40 built by Canadian Vickers. In service with the Royal Canadian Air Force, it flew with several squadrons, on anti-submarine patrols, as a training aircraft and carrying passengers. In 1944, it was disposed of.

In civil service, it was flown by Canadian Pacific Airlines until 1947, then Queen Charlotte Airlines, who replaced its original British engines with American Wright R-1820s. Queen Charlotte Airlines flew it on passenger flights until 1952, flying from Vancouver along the Pacific coast of British Columbia.

It flew with several other private owners until damaged by a ship in 1966. In 1970, it was bought by the RAF Museum and transported to the UK.

The parts of a second Stranraer, 915/CF-BYJ are owned by the Shearwater Aviation Museum, Halifax, Canada.

This aircraft also operated with Queen Charlotte Airlines until it crashed on Christmas Eve 1949 at Belize Inlet, British Columbia. Most of the aircraft was recovered in the 1980s, with the exception of the forward fuselage and cockpit.

The Supermarine Walrus was a British single-engine amphibious biplane reconnaissance aircraft designed by R. J. Mitchell and operated by the Fleet Air Arm (FAA).

It also served with the Royal Air Force (RAF), Royal Australian Air Force (RAAF), Royal Canadian Air Force (RCAF), Royal New Zealand Navy (RNZN) and Royal New Zealand Air Force (RNZAF).

Perhaps surprisingly it was the first British squadron-service aircraft to incorporate a fully-retractable main undercarriage, completely enclosed crew accommodation, and having an all-metal fuselage.

The Walrus was initially developed for service from cruisers in response to a request from the Royal Australian Air Force (RAAF), and was originally called the Seagull V; although there was little resemblance to the earlier Supermarine Seagull III. It was designed to be launched from ship-borne catapults, and was the first amphibious aircraft in the world to be launched by catapult with a full military load.

The lower wings of this biplane were set in the shoulder position with a stabilising float mounted under each one, with its horizontal tail-surfaces being positioned high on the tail-fin. The wings could be folded on ship, giving a stowage width of 17 feet 11 inches (5.46 m). The single Bristol Pegasus VI radial engine was housed in a nacelle slung from the centre section of the upper wing and powered a four-blade propeller in pusher configuration. The propeller consisted of two, two-bladed wooden propellers that were bolted onto the same hub, but offset by 90 degrees. The vortex of air created by the propeller created unequal forces on the rudder, making the aircraft yaw. The engine was offset by three degrees to starboard to counter this.

Although the aircraft typically flew with one pilot, there were positions for two. The left-hand position was the main one, with an instrument panel and a fixed seat; while the right-hand, co-pilot's seat could be folded away to allow access to the nose gun-position via a crawl-way. One of the more unusual characteristics of the aircraft was that the control column was not a fixed fitting in the usual way, but could be unplugged from either of two sockets at floor level. It became a habit for only one column to be in use; and when control was passed from the pilot to co-pilot or vice-versa, the control column would simply be unplugged and handed over. Behind the cockpit, there was a small cabin with work stations for a navigator and a radio operator.

As the Walrus was stressed to a level suitable for catapult-launching, rather surprisingly for such an ungainly-looking machine, it could be looped and bunted. This was first done by the test pilot Joseph Summers, flying the prototype at the SBAC show at Hendon in June 1933; this feat surprised even R. J. Mitchell, who was amongst the spectators. However, in practice any water in the bilges would make its presence felt when the aircraft was inverted. This usually discouraged the pilot from any future aerobatics on this type.

In 1934 an early pre-production Walrus became the first amphibian according to its manufacture to be launched from a land-based catapult.

The strength of the aircraft was demonstrated in 1935, when the prototype was attached to the battleship HMS Nelson at Gibraltar. With the naval commander-in-chief on board (Admiral Roger Backhouse) the pilot attempted a water touch-down, but with the undercarriage accidentally lowered. The Walrus was immediately flipped over but the occupants only had minor injuries; the machine was later repaired and returned to flight. Soon afterwards, the Walrus became one of the first aircraft to be fitted with an undercarriage position indicator on the instrument panel.

When flying from a warship, the Walrus would be recovered by touching-down alongside, then lifted from the sea by a ship's crane. The aircraft's lifting-gear was kept in a compartment in the section of wing directly above the engine – one of the Walrus' crew would climb onto the top wing and attach this to the crane hook. This was a straightforward procedure in calm waters, but could be very difficult if the conditions were rough. One procedure was for the parent ship to slew several degrees just before the aircraft touched down, thus creating an evanescent 'smooth' astern of the ship on which the Walrus could alight, this being followed by a fast taxi up to the ship before the 'smooth' dissipated.

Armament usually consisted of two .303 in (7.7 mm) Vickers K machine guns, one in each of the "open" positions in the nose and rear fuselage; with the capability of carrying 760 pounds (340 kg) of bombs or depth charges mounted beneath the lower wings. Like other flying boats, the Walrus carried marine equipment for use on the water, including an anchor, towing and mooring cables, drogues and a boat-hook.

The RAAF ordered 24 examples of what was originally Seagull V directly off the drawing boards which were delivered for service from cruisers from 1935; this was followed by orders from the RAF with the first production Walrus, serial number K5772, flying on 16 March 1936. It was also hoped to capitalise on the aircraft's successful exports to Japan and Spain among others.

A total of 740 Walruses were built in three major variants: the Seagull V, Walrus I, and the Walrus II. The Mark IIs were all constructed by Saunders-Roe and the prototype first flew in May 1940. This aircraft had a wooden hull, which was heavier but had the advantage of using less of the precious wartime stockpiles of light metal alloys. Saunders-Roe would go on to build under license 270 metal Mark Is and 191 wooden-hulled Mark IIs.

 

The successor to the Walrus was the Supermarine Sea Otter – a similar but more powerful design. Sea Otters never completely replaced the Walruses, and served alongside them in the air-sea rescue role during the latter part of the war. A post-war replacement for both aircraft, the Supermarine Seagull, was cancelled in 1952, with only prototypes being constructed. By that time, helicopters were taking over from small flying-boats in the air-sea rescue role.

The Walrus was affectionately known as the "Shagbat" or sometimes "Steam-pigeon"; the latter name coming from the steam produced by water striking the hot Pegasus engine.

The first Seagull V, A2-1, was handed over to the Royal Australian Air Force in 1935, with the last, A2-24 delivered in 1937. The type served aboard HMA Ships Australia, Canberra, Sydney, Perth and Hobart.

Walrus deliveries started in 1936 when the first example to be deployed was with the New Zealand division of the Royal Navy, on HMS Achilles – one of the Leander class light cruisers that carried one Walrus each. The Royal Navy Town class cruisers carried two Walruses during the early part of the war and Walruses also equipped the York class and County class heavy cruisers. Some battleships, such as HMS Warspite and HMS Rodney carried Walruses, as did the monitor HMS Terror and the seaplane tender HMS Albatros.

By the start of World War II the Walrus was in widespread use. Although its principal intended use was gunnery spotting in naval actions, this only occurred twice: Walruses from HMS Renown and HMS Manchester were launched in the Battle of Cape Spartivento and a Walrus from HMS Gloucester was used in the Battle of Cape Matapan. The main task of ship-based aircraft was patrolling for Axis submarines and surface-raiders, and by March 1941, Walruses were being deployed with Air to Surface Vessel (ASV) radars to assist in this. During the Norwegian Campaign and the East African Campaign, they also saw very limited use in bombing and strafing shore targets.

By 1943, catapult-launched aircraft on cruisers and battleships were being phased out; their role at sea was taken over by much improved radar. Also, a hangar and catapult occupied a considerable amount of valuable space on a warship. However, Walruses continued to fly from Royal Navy carriers for air-sea rescue and general communications tasks. Their low landing speed meant they could make a carrier landing despite having no flaps or tailhook.

The RAF used Walruses mainly in the Air-sea rescue role. The specialist air-sea rescue squadrons flew a variety of aircraft, using Spitfires and Boulton Paul Defiants to patrol for downed aircrew, Avro Ansons to drop supplies and dinghies, and Walruses to pick up aircrew from the water.

RAF air-sea rescue squadrons were deployed to cover the waters around the United Kingdom, the Mediterranean Sea and the Bay of Bengal.

Three Walruses, delivered in March 1939, were used by Irish Air Corps as maritime patrol aircraft during the Irish Emergency of World War II.

After the war, some Walruses continued to see limited military use with the RAF and foreign navies. Eight were operated by Argentina, two flew from the cruiser ARA La Argentina as late as 1958. Other aircraft were used for training by the French Navy's Aviation navale.

Walruses also found civil and commercial use. They were briefly used by a whaling company, United Whalers. Operating in the Antarctic, they were launched from the Factory ship FF Balaena, that had been equipped with an ex-navy aircraft catapult. A Dutch whaling company embarked Walruses, but never flew them. Other Walruses found use carrying passengers.

 

 

 

 

 

 

 

References

Aversa, R., R.V.V. Petrescu, A. Apicella and F.I.T. Petrescu, 2017a. Nano-diamond hybrid materials for structural biomedical application. Am. J. Biochem. Biotechnol.

Aversa, R., R.V. Petrescu, B. Akash, R.B. Bucinell and J.M. Corchado et al., 2017b. Kinematics and forces to a new model forging manipulator. Am. J. Applied Sci., 14: 60-80.

Aversa, R., R.V. Petrescu, A. Apicella, I.T.F. Petrescu and J.K. Calautit et al., 2017c. Something about the V engines design. Am. J. Applied Sci., 14: 34-52.

Aversa, R., D. Parcesepe, R.V.V. Petrescu, F. Berto and G. Chen et al., 2017d. Process ability of bulk metallic glasses. Am. J. Applied Sci., 14: 294-301.

Aversa, R., R.V.V. Petrescu, B. Akash, R.B. Bucinell and J.M. Corchado et al., 2017e. Something about the balancing of thermal motors. Am. J. Eng. Applied Sci., 10: 200.217. DOI: 10.3844/ajeassp.2017.200.217

Aversa, R., F.I.T. Petrescu, R.V. Petrescu and A. Apicella, 2016a. Biomimetic FEA bone modeling for customized hybrid biological prostheses development. Am. J. Applied Sci., 13: 1060-1067. DOI: 10.3844/ajassp.2016.1060.1067

Aversa, R., D. Parcesepe, R.V. Petrescu, G. Chen and F.I.T. Petrescu et al., 2016b. Glassy amorphous metal injection molded induced morphological defects. Am. J. Applied Sci., 13: 1476-1482.

Aversa, R., R.V. Petrescu, F.I.T. Petrescu and A. Apicella, 2016c. Smart-factory: Optimization and process control of composite centrifuged pipes. Am. J. Applied Sci., 13: 1330-1341.

Aversa, R., F. Tamburrino, R.V. Petrescu, F.I.T. Petrescu and M. Artur et al., 2016d. Biomechanically inspired shape memory effect machines driven by muscle like acting NiTi alloys. Am. J. Applied Sci., 13: 1264-1271.

Aversa, R., E.M. Buzea, R.V. Petrescu, A. Apicella and M. Neacsa et al., 2016e. Present a mechatronic system having able to determine the concentration of carotenoids. Am. J. Eng. Applied Sci., 9: 1106-1111.

Aversa, R., R.V. Petrescu, R. Sorrentino, F.I.T. Petrescu and A. Apicella, 2016f. Hybrid ceramo-polymeric nanocomposite for biomimetic scaffolds design and preparation. Am. J. Eng. Applied Sci., 9: 1096-1105.

Aversa, R., V. Perrotta, R.V. Petrescu, C. Misiano and F.I.T. Petrescu et al., 2016g. From structural colors to super-hydrophobicity and achromatic transparent protective coatings: Ion plating plasma assisted TiO2 and SiO2 Nano-film deposition. Am. J. Eng. Applied Sci., 9: 1037-1045.

Aversa, R., R.V. Petrescu, F.I.T. Petrescu and A. Apicella, 2016h Biomimetic and Evolutionary Design Driven Innovation in Sustainable Products Development, Am. J. Eng. Applied Sci., 9: 1027-1036.

Aversa, R., R.V. Petrescu, A. Apicella and F.I.T. Petrescu, 2016i. Mitochondria are naturally micro robots-a review. Am. J. Eng. Applied Sci., 9: 991-1002.

Aversa, R., R.V. Petrescu, A. Apicella and F.I.T. Petrescu, 2016j. We are addicted to vitamins C and E-A review. Am. J. Eng. Applied Sci., 9: 1003-1018.

Aversa, R., R.V. Petrescu, A. Apicella and F.I.T. Petrescu, 2016k. Physiologic human fluids and swelling behavior of hydrophilic biocompatible hybrid ceramo-polymeric materials. Am. J. Eng. Applied Sci., 9: 962-972.

Aversa, R., R.V. Petrescu, A. Apicella and F.I.T. Petrescu, 2016l. One can slow down the aging through antioxidants. Am. J. Eng. Applied Sci., 9: 1112-1126.

Aversa, R., R.V. Petrescu, A. Apicella and F.I.T. Petrescu, 2016m. About homeopathy or jSimilia similibus curenturk. Am. J. Eng. Applied Sci., 9: 1164-1172.

Aversa, R., R.V. Petrescu, A. Apicella and F.I.T. Petrescu, 2016n. The basic elements of life's. Am. J. Eng. Applied Sci., 9: 1189-1197.

Aversa, R., F.I.T. Petrescu, R.V. Petrescu and A. Apicella, 2016o. Flexible stem trabecular prostheses. Am. J. Eng. Applied Sci., 9: 1213-1221.

Mirsayar, M.M., V.A. Joneidi, R.V.V. Petrescu,    F.I.T. Petrescu and F. Berto, 2017 Extended MTSN criterion for fracture analysis of soda lime glass. Eng. Fracture Mechanics 178: 50-59.     DOI: 10.1016/j.engfracmech.2017.04.018

Petrescu, R.V. and F.I. Petrescu, 2013a. Lockheed Martin. 1st Edn., CreateSpace, pp: 114.

Petrescu, R.V. and F.I. Petrescu, 2013b. Northrop. 1st Edn., CreateSpace, pp: 96.

Petrescu, R.V. and F.I. Petrescu, 2013c. The Aviation History or New Aircraft I Color. 1st Edn., CreateSpace, pp: 292.

Petrescu, F.I. and R.V. Petrescu, 2012. New Aircraft II. 1st Edn., Books On Demand, pp: 138.

Petrescu, F.I. and R.V. Petrescu, 2011. Memories About Flight. 1st Edn., CreateSpace, pp: 652.

Petrescu, F.I.T., 2009. New aircraft. Proceedings of the 3rd International Conference on Computational Mechanics, Oct. 29-30, Brasov, Romania.

Petrescu, F.I., Petrescu, R.V., 2016a Otto Motor Dynamics, GEINTEC-GESTAO INOVACAO E TECNOLOGIAS, 6(3):3392-3406.

Petrescu, F.I., Petrescu, R.V., 2016b Dynamic Cinematic to a Structure 2R, GEINTEC-GESTAO INOVACAO E TECNOLOGIAS, 6(2):3143-3154.

Petrescu, F.I., Petrescu, R.V., 2014a Cam Gears Dynamics in the Classic Distribution, Independent Journal of Management & Production, 5(1):166-185.

Petrescu, F.I., Petrescu, R.V., 2014b High Efficiency Gears Synthesis by Avoid the Interferences, Independent Journal of Management & Production, 5(2):275-298.

Petrescu, F.I., Petrescu R.V., 2014c Gear Design, ENGEVISTA, 16(4):313-328.

Petrescu, F.I., Petrescu, R.V., 2014d Balancing Otto Engines, International Review of Mechanical Engineering 8(3):473-480.

Petrescu, F.I., Petrescu, R.V., 2014e Machine Equations to the Classical Distribution, International Review of Mechanical Engineering 8(2):309-316.

Petrescu, F.I., Petrescu, R.V., 2014f Forces of Internal Combustion Heat Engines, International Review on Modelling and Simulations 7(1):206-212.

Petrescu, F.I., Petrescu, R.V., 2014g Determination of the Yield of Internal Combustion Thermal Engines, International Review of Mechanical Engineering 8(1):62-67.

Petrescu, F.I., Petrescu, R.V., 2014h Cam Dynamic Synthesis, Al-Khwarizmi Engineering Journal, 10(1):1-23.

Petrescu, F.I., Petrescu R.V., 2013a Dynamic Synthesis of the Rotary Cam and Translated Tappet with Roll, ENGEVISTA  15(3):325-332.

Petrescu, F.I., Petrescu, R.V., 2013b Cams with High Efficiency, International Review of Mechanical Engineering 7(4):599-606.

Petrescu, F.I., Petrescu, R.V., 2013c An Algorithm for Setting the Dynamic Parameters of the Classic Distribution Mechanism, International Review on Modelling and Simulations 6(5B):1637-1641.

Petrescu, F.I., Petrescu, R.V., 2013d Dynamic Synthesis of the Rotary Cam and Translated Tappet with Roll, International Review on Modelling and Simulations 6(2B):600-607.

Petrescu, F.I., Petrescu, R.V., 2013e Forces and Efficiency of Cams, International Review of Mechanical Engineering 7(3):507-511.

Petrescu, F.I., Petrescu, R.V., 2012a Echilibrarea motoarelor termice, Create Space publisher, USA, November 2012, ISBN 978-1-4811-2948-0, 40 pages, Romanian edition.

Petrescu, F.I., Petrescu, R.V., 2012b Camshaft Precision, Create Space publisher, USA, November 2012, ISBN 978-1-4810-8316-4, 88 pages, English edition.

Petrescu, F.I., Petrescu, R.V., 2012c Motoare termice, Create Space publisher, USA, October 2012, ISBN 978-1-4802-0488-1, 164 pages, Romanian edition.

Petrescu, F.I., Petrescu, R.V., 2011a Dinamica mecanismelor de distributie, Create Space publisher, USA, December 2011, ISBN 978-1-4680-5265-7, 188 pages, Romanian version.

Petrescu, F.I., Petrescu, R.V., 2011b Trenuri planetare, Create Space publisher, USA, December 2011, ISBN 978-1-4680-3041-9, 204 pages, Romanian version.

Petrescu, F.I., Petrescu, R.V., 2011c Gear Solutions, Create Space publisher, USA, November 2011, ISBN 978-1-4679-8764-6, 72 pages, English version.

Petrescu, F.I. and R.V. Petrescu, 2005. Contributions at the dynamics of cams. Proceedings of the 9th IFToMM International Symposium on Theory of Machines and Mechanisms, (TMM’ 05), Bucharest, Romania, pp: 123-128.

Petrescu, F. and R. Petrescu, 1995. Contributii la sinteza mecanismelor de distributie ale motoarelor cu ardere internã. Proceedings of the ESFA Conferinta, (ESFA’ 95), Bucuresti, pp: 257-264.

Petrescu, FIT., 2015a Geometrical Synthesis of the Distribution Mechanisms, American Journal of Engineering and Applied Sciences, 8(1):63-81. DOI: 10.3844/ajeassp.2015.63.81

Petrescu, FIT., 2015b Machine Motion Equations at the Internal Combustion Heat Engines, American Journal of Engineering and Applied Sciences, 8(1):127-137. DOI: 10.3844/ajeassp.2015.127.137

Petrescu, F.I., 2012b Teoria mecanismelor – Curs si aplicatii (editia a doua), Create Space publisher, USA, September 2012, ISBN 978-1-4792-9362-9, 284 pages, Romanian version, DOI: 10.13140/RG.2.1.2917.1926

Petrescu, F.I., 2008. Theoretical and applied contributions about the dynamic of planar mechanisms with superior joints. PhD Thesis, Bucharest Polytechnic University.

Petrescu, FIT.; Calautit, JK.; Mirsayar, M.; Marinkovic, D.; 2015 Structural Dynamics of the Distribution Mechanism with Rocking Tappet with Roll, American Journal of Engineering and Applied Sciences, 8(4):589-601. DOI: 10.3844/ajeassp.2015.589.601

Petrescu, FIT.; Calautit, JK.; 2016 About Nano Fusion and Dynamic Fusion, American Journal of Applied Sciences, 13(3):261-266.

Petrescu, R.V.V., R. Aversa, A. Apicella, F. Berto and S. Li et al., 2016a. Ecosphere protection through green energy. Am. J. Applied Sci., 13: 1027-1032. DOI: 10.3844/ajassp.2016.1027.1032

Petrescu, F.I.T., A. Apicella, R.V.V. Petrescu, S.P. Kozaitis and R.B. Bucinell et al., 2016b. Environmental protection through nuclear energy. Am. J. Applied Sci., 13: 941-946.

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Bucinell, Ronald; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017a Modern Propulsions for Aerospace-A Review, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Bucinell, Ronald; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017b Modern Propulsions for Aerospace-Part II, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Bucinell, Ronald; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017c History of Aviation-A Short Review, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Bucinell, Ronald; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017d Lockheed Martin-A Short Review, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017e Our Universe, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017f What is a UFO?, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, RV., Aversa, R., Akash, B., Corchado, J., Berto, F., Mirsayar, MM., Apicella, A., Petrescu, FIT., 2017 About Bell Helicopter FCX-001 Concept Aircraft-A Short Review, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, RV., Aversa, R., Akash, B., Corchado, J., Berto, F., Mirsayar, MM., Apicella, A., Petrescu, FIT., 2017 Home at Airbus, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, RV., Aversa, R., Akash, B., Corchado, J., Berto, F., Mirsayar, MM., Kozaitis, S., Abu-Lebdeh, T., Apicella, A., Petrescu, FIT., 2017 Airlander, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, RV., Aversa, R., Akash, B., Corchado, J., Berto, F., Apicella, A., Petrescu, FIT., 2017 When Boeing is Dreaming – a Review, Journal of Aircraft and Spacecraft Technology, 1(1).