v1.0.2 / 01 jan 02 / greg goebel / public domain
* The biplane was clearly an obsolete concept by the beginning of the Second World War; and so it is somewhat surprising that one biplane, the British Fairey "Swordfish" torpedo bomber, proved to be a highly effective weapon. The Swordfish remained in first line-service through the entire war in Europe, and even outlasted aircraft designed to replace it. This document provides a short history of the Swordfish.
* The Swordfish started out in 1933 as a private venture by Fairey Aviation Company Limited, in the form of the three-seat "Torpedo Spotter Reconnaissance I (TSR.I)" aircraft. The TSR.I was a biplane of frame-and-fabric construction, powered by a Bristol Pegasus IIM radial engine with 635 horsepower.
The TSR.I first flew in March 1933, and was put through a successful series of tests. Unfortunately, in September of that year, during spin tests the prototype failed to recover from a flat spin that that took it into the ground. The pilot was able to bail out with some difficulty, but the aircraft was destroyed.
The TSR.I had been promising enough to justify further work, and when the British Air Ministry issued Specification S.15/33, requesting a carrier-based torpedo bomber and scout aircraft, Fairey built a second prototype, the "TSR.II", which first flew on 17 April 1934. The new aircraft included an uprated Pegasus IIIM3 engine (with up to 690 horsepower), aerodynamic changes to improve spin handling, a longer fuselage, and slightly swept back wings to compensate for the longer fuselage.
Land trials went well, and in November 1934, the TSR.II was fitted with floats for sea trials, which culminated in catapult launch and recovery by the battle cruiser HMS REPULSE. The floats were then traded back to landing wheels for final evaluation. The Air Ministry was suitably impressed and placed an order for three pre-production machines.
The first of the three pre-production aircraft, now named the Swordfish, was flown on 31 December 1935. The last of the three was fitted with floats for service trials on water. The three prototypes were followed by a production order for 68 Swordfish "Mark I" aircraft.
By 1938, the Swordfish had replaced all other torpedo bombers in the service Royal Navy's Fleet Air Arm (FAA). By the outbreak of World War II in September 1939, thirteen squadrons had been equipped with the "Stringbag", as it came to be known, with twelve of the squadrons at sea on the carriers HMS ARK ROYAL, COURAGEOUS, EAGLE, FURIOUS, and GLORIOUS.
By the end of the war there would be thirteen more operational squadrons flying the Swordfish. The last operational squadron was established in June 1943, and was staffed by Dutch naval personnel fighting in exile. Twenty training squadrons were built up as well.
Production of the Swordfish was shifted from Fairey to Blackburn Aircraft LTD in early 1940. Blackburn continued production of the Mark I until 1943, when the "Mark II" was introduced, which was fitted for rockets. Later Mark II production also featured an uprated Pegasus 30 engine, with 750 horsepower, instead of the Pegasus IIIM3.
The "Mark III" added a Mark X "Air to Surface Vessel (ASV)" radar pod between the landing gear, as well as fittings for rocket-assisted takeoff. The "Mark IV" was a Mark II with an enclosed cockpit, built for operations in Canada.
The Swordfish was, as noted, a frame-and-fabric biplane with a frame mostly made of tubular steel. The radial engine drove a three-bladed fixed-pitch metal propeller, though the TSR.2 had been fitted with a two-bladed propeller. The aircraft had fixed landing gear, which could be easily exchanged for floats, and its wings could be pivoted back along the fuselage to allow compact storage on board a carrier or cruiser.
The Swordfish had accommodations for three crew members: pilot, observer,
and radioman-gunner. It was armed with a single fixed Vickers 7.7 millimeter
(0.303 inch) machine gun firing forward and a rear-mounted Vickers or Lewis
7.7 millimeter gun handled by the radioman-gunner.
FAIREY SWORDFISH MK.2 / MK.3:
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spec metric english
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wingspan 13.9 meters 45 feet 6 inches
length 10.4 meters 35 feet 8 inches
height 3.8 meters 12 feet 4 inches
empty weight 2,130 kilograms 4,700 pounds
max loaded weight 3,410 kilograms 7,510 pounds
maximum speed 225 KPH 140 MPH / 120 KT
service ceiling 3,260 meters 10,700 feet
range 880 kilometers 550 MI / 480 NMI
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This data is for a Swordfish with no floats and fitted for torpedo
bombing.
* The Swordfish saw little action during 1939 and the first few months of 1940, operating mostly in convoy escort and for naval cover. Its first real action was in April 1940, when it served in the naval battles that accompanied the Nazi invasion of Norway.
Norway fell, but the German surface navy was badly mauled in the operation. On 11 April, Swordfish operating off the carrier HMS FURIOUS launched a torpedo attack on two destroyers at harbor in Trondheim. The attack was ineffectual, but it was the first airborne torpedo attack of the war.
Two days later, on 13 April, a Swordfish launched by catapult off the HMS WARSPITE flew up Ofot Fjord, which led to Narvik, and spotted seven German destroyers for the WARSPITE's guns. All the destroyers were sunk or so badly damaged that they had to be scuttled. There were no casualties on the British side. The Swordfish in question also discovered a German submarine, the U-64, and sank it in a dive-bombing attack. It was the first U-boat sunk by an FAA aircraft in the war.
Over the next two weeks, Swordfish conducted constant sorties in Norwegian waters, performing strikes, reconnaissance, and antisubmarine patrols under severe weather conditions. Flying in bad weather was a particularly unpleasant prospect because the Stringbag didn't have an enclosed cockpit.
At the same time, Swordfish attached to the Royal Air Force (RAF) Coastal Command were operating out of the UK on mine-laying missions against German ports. The next month, the Nazi "Blitzkrieg" against the Low Countries and France forced the British to call on every resource they had to stave off disaster. Four squadrons of Swordfish in all were attached to Coastal Command and put to every task for which they were capable: mine-laying, bombing of naval and ground targets, spotting, and reconnaissance.
Swordfish operating out of the south of France took part in bombing raids against Italian targets in June, when Italy declared war against the French and British. A number of Swordfish left France and eventually ended up on the island of Malta, where they would successfully harass Axis shipping during the battle for North Africa.
When France fell in July, the British took ruthless action to prevent French military assets from being used against them, striking at and demolishing the French fleet at dock in the harbor of Oran, in Algeria. Twelve Swordfish from the carrier HMS ARK ROYAL launched a torpedo attack on the battle cruiser DUNKERQUE, putting it out of action.
The next month, on 22 August, three Swordfish operating from land attacked Italian warships sitting in the port of Bomba Bay, in Libya, destroying two submarines, a submarine tender, and a destroyer. The attackers sank four ships with only three torpedoes, as the destroyer was not hit directly but went up when the tender exploded.
The success of these attacks on ships in harbor led the British to consider a much more aggressive operation against the Italian Navy: a torpedo-bomber attack against the Italian Fleet at Taranto, their main bases on the Italian mainland.
* An attack on Taranto had actually been considered in 1938, when war was becoming inevitable. In 1940, the strike plans were dusted off and updated.
The main Italian fleet consisted of six battleships, consisting of two of the new LITTORIO class and four of the recently rebuilt CAVOUR and DULIO class, plus five cruisers and twenty destroyers, all based at Taranto. Attacking the Italian fleet at anchor required high quality and up-to-date intelligence and reconnaissance, not merely to determine what ships were present but also to know their positions. The British strike force would also have to move silently to achieve surprise.
The plan specified a night attack to reduce losses, and so Swordfish crews were put through a rigorous schedule of training for night flight and combat. The mission was scheduled for 21 October 1940, but was delayed to 11 November because of other naval commitments.
A few days before the mission, the carrier EAGLE ran into trouble with her fuel systems. Several of her Swordfish were transferred to the carrier ILLUSTRIOUS, which then sailed from Alexandria, Egypt.
Aerial reconnaissance on the morning of 11 November indicated that five Italian battleships were in Taranto harbor, with three cruisers at dock protected by antisubmarine nets. The sixth battleship was seen to enter the harbor later that day.
By 8:00 PM that evening, the ILLUSTRIOUS and her escorts were in position, about 270 kilometers (170 miles) from the port. Twelve Swordfish were fitted up for the first wave of the attack: six carried torpedoes, four carried bombs, and two carried a combination of bombs and flares. The rear gunners were left behind, since their position was taken up by an additional fuel tank.
The first Swordfish took off at 8:35, and by 9:00, they were all in the air and on the way. Just before 11:00 PM, the two flare-droppers split off from the formation. One put a line of flares over the harbor from 2,300 meters (7,500 feet) and then bombed an oil storage depot. The strike aircraft attacked in two groups; the flight leader's plane was hit by flak and went down, but multiple hits were scored on several of the battleships.
In the meantime, a second wave had taken to the air about a half hour after the first. The second wave consisted of five aircraft armed with torpedoes, two armed with bombs, and two armed with flares and bombs. One had to turn back because of a technical problem, but the other eight arrived at about midnight and repeated the performance of the first wave, slamming torpedoes into the sitting battleships under the glare of the flares. Another Swordfish was lost to flak.
All the aircraft, except the two that had been shot down, were back on board the ILLUSTRIOUS before 3:00 AM that morning. Aerial reconnaissance conducted two days later indicated that one Cavour and one Dulio-class battleship were heavily damaged and beached; one Littorio battleship badly damaged; two cruisers and two destroyers badly damaged; and two auxiliary vessels sunk.
It was a brilliant action, inflicting massive damage on the Italian fleet with minimal losses to the British. The Italians withdrew their fleet to the north, effectively removing it from the game board. The successful raid on Taranto suggested to Japanese planners that they might be able to imitate the same tactics for their own purposes.
* The Swordfish saw further action in the Mediterranean and the Mideast into the spring of 1941, but the aircraft's next shining role was in helping to sink the German battleship BISMARCK. On 23 May 1941, the BISMARCK was observed steaming south through the gap between Greenland and Iceland; British fleet elements steamed out to intercept her.
On 24 May, the new carrier VICTORIOUS launched nine Swordfish at 10:00 PM in the evening, but weather conditions were bad and the torpedo bombers only scored a single hit. The BISMARCK escaped, only to be spotted again by an RAF Coastal Command Consolidated Catalina flying boat on 26 May.
Fifteen Swordfish were launched by the carrier ARK ROYAL that day, but attacked the British cruiser SHEFFIELD by mistake. Fortunately, another error balanced the first: the aircrafts' torpedoes had been armed with magnetic detonators, which were hopelessly unreliable, and the SHEFFIELD, maneuvering wildly in rough seas, escaped unscathed.
There was no time for recriminations and the fiasco proved valuable. Late in the day, fifteen Swordfish were launched in a storm, carrying torpedoes armed with more reliable contact detonators. They scored two hits on the German battleship: one did no damage, but the other struck the vessel in her steering gear, forcing her to steam in circles.
None of the aircraft were lost in the attack, though a German officer said: "It was incredible to see such obsolete-looking planes having the nerve to attack a fire-spitting mountain like the BISMARCK." The BISMARCK was sent to the bottom by Royal Navy shellfire the next day.
By this time, Hitler had judged his own surface fleet to be inadequate to standing up to the Royal Navy and deployed them cautiously, under plenty of protection. When the German battleships SCHARNHORST, GNEISENAU, and PRINZ EUGEN left the French port of Brest on 12 February 1942, moving to Northern European ports where they would be less vulnerable to air attack, six Swordfish attacked and were all shot down by covering fighters. Of the 18 crewmen, only five survived. Lieutenant Commander Esmonde, who led the attack, was posthumously awarded the Victoria Cross.
The Swordfish was never again used as a torpedo bomber. However, it had already been and would continue to be employed in another role against Hitler's main weapon in the Battle of the Atlantic: the U-boat.
* The Swordfish had been equipped with ASV radar as early as October 1940, to help it hunt down German U-boats cruising on the surface. Two months later, on 21 December 1941, a Swordfish operating from Gibraltar was the first aircraft to sink a submarine at night. A year and a half later, on 23 May 1943, a Swordfish was the first aircraft to prove the effectiveness of rockets in antisubmarine warfare when one Stringbag sunk the U-752 off the coast of Ireland, even though the U-boat put up a strong defense with its quadruple 20-millimeter flak gun.
May 1943 was the turning point in the Battle of the Atlantic. The Swordfish was one of the many weapons that inflicted enough losses on the German submarine force to finally give the Allies the upper hand in the battle for the sea lanes. The Swordfish was relatively easy to fly off tiny escort carriers, and so could provide cover for convoys from start to finish. The Swordfish proved particularly effective in escorting the Murmansk convoys to Russia through frigid Arctic waters.
In August 1944, Swordfish IIs operating from the escort carriers VINDEX and STRIKER as part of the Murmansk convoy JW.59 took on a wolf pack of nine U-boats that were attempting to attack the convoy. One U-boat was sunk, another damaged; the defense was so energetic that none of the ships in the convoy was sunk. When the carriers escorted a return convoy back from Russia, no U-boats attempted to attack it.
Swordfish would be credited with the sinking of 12 U-boats in all.
* The final Swordfish was delivered in August 1944. Fairey had built 692 and Blackburn 1,699, for a total of 2,391. The last operational squadron was disbanded on 21 May 1945, shortly after the fall of Germany, and the last training squadron was disbanded in the summer of 1946.
Despite its obsolescent appearance, the Stringbag had proven an excellent weapon, though its usefulness would have been far more limited if it had ever faced significant fighter opposition.
* The Swordfish today is represented by a handful of museum pieces and three flying examples, including two in the UK, one in Canada. Anyone finding a derelict Swordfish airframe today would indeed have a prize on his or her hands.
The story of the blundering Swordfish attack on the HMS SHEFFIELD and the failure of the magnetic detonators is part of another interesting story. Magnetic detonators were designed to cause a torpedo to explode while it was passing underneath the hull of a ship, without actually striking it. The idea was that this would inflict greater and more devastating damage than a torpedo hitting the side of the ship.
The idea sounded nice in principle, but failed miserably in practice, and most European nations quickly got rid of the magnetic detonators. In the early days of the war in the South Pacific, however, American submarine commanders were specifically ordered to use magnetic detonators. They protested at length that the detonators didn't work, but the high command stubbornly continued to insist on their use. Submarine commanders resorted to leaving port with magnetic detonators fitted to their torpedoes, only to replace them with contact detonators once they got to sea and no longer had to put up with inspections.
American torpedoes suffered from two other serious problems: they ran below their depth setting, and the contact detonators were often defective It took a long time to fix these problems, and they were only resolved by the stubbornness of the submariners who had tried to use the torpedoes in combat; the Navy research labs only took action when given proof they could no longer deny.
* Sources include:
* Revision history:
v1.0 / 16 aug 97 / gvg
v1.1 / 01 feb 98 / gvg / Minor polishing and correction.
v1.0.2 / 01 jan 02 / gvg / Minor polishing & corrections.