Torpedo Bombers, 1900–1950: An Illustrated History

By Jean-Denis Lepage

The torpedo-bomber was a very short-lived weapon system, operational for scarcely half a century from just prior WWI to the 1960s. Yet during its brief existence it transformed naval warfare, extending the ship-killing range of ships and coastal defences to hundreds of miles. The Royal Navy and Fleet Air Arm led the way, recording the first sinking of a ship by aerial torpedo in August 1915 but all major navies eagerly developed their own torpedo bomber forces.

The torpedo-bomber reached its zenith in WWII, particularly from 1940-42, with notable successes at the Battle of Taranto, the sinking of the Bismarck and Pearl Harbor. It was the weapon of choice for both the US and Japanese in the big Pacific battles such as Midway. In the latter stages of the war, increasingly effective anti-aircraft fire and interceptor aircraft started to render it obsolete, a process completed post-war by long-range anti-ship missiles.

Jean-Denis Lepage traces the development of torpedo bombers worldwide, describing their tactics, operational history and the aircraft themselves, including such well-loved types as the Swordfish, Beaufighter and Avenger. Over 300 aircraft are beautifully illustrated.

• Language: English
• Publisher: Pen and Sword
• Release date: Jan 27, 2020
• ISBN: 9781526763488

Jean-Denis Lepage

Jean-Denis Lepage was born in 1952 at Meaux (France) near Paris. After studying English at the University of Angers (Maine-et-Loire), Jean-Denis worked in the UK before moving to Groningen in The Netherlands. He now works as a free-lance translator, illustrator and author. He has published several books with the accent on fortifications and WW 2.

Book preview

PART ONE

EARLY TORPEDO BOMBERS

Chapter 1

Torpedo

Atorpedo is a cigar-shaped, self-propelled weapon with an explosive warhead, launched from a ship or submarine or dropped into the water by an aircraft and propelled below the water surface. The projectile is intended to explode on reaching a target (most often a ship). The term torpedo was originally employed for a variety of different explosive devices, most of which today would be called shells, rounds, naval or floating mines, land mines or booby-traps. From about 1900, the word torpedo has been strictly used to designate an underwater self-propelled explosive weapon. The very term torpedo comes from the Latin torpere (stiffened or numbed). It was given to a species of fish: a group of large flat rays that can discharge electricity (electric or torpedo rays).

When it became practicable for military use, the torpedo gradually had a tremendous impact on naval warfare. It became an important weapon as it meant that a small surface ship, a sneaking submarine, a furtive little team of frogmen or a single tiny one-seat airplane could damage, destroy and sink even the largest of armoured battleships.

The first working prototype of the modern self-propelled sea torpedo was created in 1864 by a commission placed by Giovanni Luppis, an Austrian naval officer from Fiume, and Robert Whitehead, an English engineer. Whitehead continued to improve his weapon in the 1870s and opened a manufacturing and test site in Portland Harbour, Dorset, Great Britain in 1890. The self-propelled Whitehead torpedo of 1866 used compressed air as its energy source. It was able to travel about 180 metres (200 yards) at an average speed of 12 km/h (6.5 knots). The speed and range of later models was improved by increasing the pressure and the quantity of stored air.

From 1885 to 1895 American Lieutenant Commander John A. Howell made another torpedo design; simpler and cheaper as it was driven by flywheel, which had to be spun up before launch. It was able to travel about 400 yards (370m) at 25 knots (46 km/h). By the last years of the nineteenth century and the start of the twentieth, numerous technical refinements and improvements (e.g. hydrostatic valves, gyroscopic control equipment, larger warhead and electric propulsion systems with batteries avoiding tell-tale bubbles) were continuously introduced, resulting in torpedoes becoming standard equipment in the navies of all industrial nations. Torpedoes rapidly appeared as weapons of terrible effect. The first recorded successful attack with a torpedo took place during the Russo-Turkish War of 1877–78. Another early success occurred during the Chilean Civil War in 1891. During the First Sino-Japanese War in 1894, the Chinese warship Dingyuan was hit and disabled by a torpedo launched by Japanese torpedo boats. The Russo-Japanese War (1904–1905) was the first modern war of the twentieth century. It saw the mass deployment of newly-built steel battleships, cruisers, fledgling destroyers and submarines, and the torpedo boat, notably during the Battle of Tsushima in May 1905.

The first recorded successful launch of a self-propelled torpedo in battle by a submarine was on 9 December 1912 during the Balkan Wars, when the Greek submarine Delfin sank the Turkish cruiser Mezdiye.

Electric rays (aka torpedoes or numbfishes) are known for being capable of producing an electric discharge, ranging from 8 to 220 volts depending on species, used to stun prey and for defence.

Torpedo: the modern torpedo is a self-propelled weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target and designed to detonate on contact with the target.

The floating torpedo designed in 1866 by Robert Whitehead had a length of 11ft. It was propelled just under water level by compressed air, and was supposed to hit a target at about 700 yards at a speed of approximately 7 knots.

A torpedo includes three basic parts: 1) the warhead, detonated by a primer placed in the nose of the device; 2) the energy section containing fuel supply, e.g. compressed air tanks or electric batteries; and 3) the propelling part comprising an engine or electric motor that steered two sets of contra-rotating propellers and gyro-stabilized rudders

Plan of a fast torpedo boat showing the position of the launching tubes. On smaller vessels torpedoes were carried in fixed deck-mounted tubes using compressed air. The launching tubes were either aligned to fire forward or at an offset angle from the centreline.

Torpedo boat: in the late nineteenth century appeared a new weapon, the naval torpedo, and therefore a new specialized type of military ship, the torpedo boat. This was usually a relatively small and fast vessel. Though they had to sail through a hail of surface fire to get close enough to attack, their torpedoes could inflict enough damage to turn back a superior force of cruisers and battleships. By the First World War powerful engines and planing hull designs were capable of quite high speeds. Relatively small torpedo boats evolved that were 50 to 100ft (15 to 30m) in length with a maximum speed of 30 to 50 knots (56 to 93 km/h), carrying two to four torpedoes fired from simple fixed launchers. Additional armament included machine guns and small-calibre quick-firing cannon. The introduction of the torpedo boat was a serious concern to navies of the era, and destroyers appeared in response. Torpedo Boat Destroyers (TBDs) were fast, heavily-armed and manoeuvrable warships of long endurance intended to escort larger vessels in a fleet, convoy or battle group and defend them against small, short-range attackers.

The Second World War saw the appearance of the British Royal Navy’s Motor Torpedo Boat (MTB), the German Kriegsmarine Schnell-Boot (S-Boot in short, meaning ‘fast boat’), and the US navy PT (Patrol Torpedo) boats. The depicted German S-Boot type S38 used during the Second World War was introduced in 1942. Each of her three Daimler-Benz diesel engines produced a remarkable 4,800 bhp, giving her a top speed of 42 knots (81 km/h or 50 mph). The S-Boot had a good sea-keeping ability, and was operated by a crew of twenty-one. She was equipped with two enclosed forward-firing tubes that could launch four 533mm torpedoes. She was armed with one 2cm cannon forward and one 3.7cm gun aft. Eight sea mines could be carried at the stern.

A submarine is a vessel capable of independent operation underwater. Submarines were introduced in the last years of the nineteenth century and were first successfully used during the First World War. Most submarines consist of a cylindrical body with hemispherical and/or conical ends and a vertical structure called the conning tower usually located amidships housing communications, watertight hatches and sensing devices as well as a periscope to survey the surface of the sea. A submarine can rapidly submerge by flooding her ballast tanks, and surface when and where required by blowing out the water with compressed air pumps. When on the surface she was powered by diesel or turbine engines, and when submerged by electric motors. Military usage of the submarine included attacking enemy surface ships (merchant and military) using a gun placed on the foredeck, or launching self-propelled torpedoes. On a submarine the torpedo launching tubes were usually placed at the bow.

Chapter 2

Torpedo Bombers

Early military aircraft

On 17 December 1903 at Kitty Hawk, North Carolina, the American inventors and aviators Orville and Wilbur Wright made the first controlled and powered flight in a heavier-than-air machine. From then on, pioneers all over the world experimented and tried to make aircraft a viable proposition. Remarkably, in a very short time a wide variety of aircraft were designed, tested and constructed. Soon small aircraft-building companies appeared and monoplanes, biplanes, triplanes and seaplanes became available.

In the early 1910s the threat of a European war accelerated the development of both military and civilian lighter-than-air airships (balloons and zeppelins) and heavier-than-air aeroplanes. However, none of the industrialized powers had a clear idea of either the purpose or use of aircraft as a weapon of war. Indeed, the military authorities were not unanimous about the future usefulness of aircraft in general and the torpedo bomber in particular.

When aircraft became practicable, the idea of dropping explosive devices (grenades, bombs or torpedoes) from a low-flying craft was envisaged.

Early aircraft were flimsy designs and fragile structures with unreliable engines and extremely low performance. However, technical development and improvements in speed, range, ceiling and reliability came with amazing rapidity.

Torpedo bombers

As the designation implies, the torpedo bomber was a military aircraft designed primarily to attack targets at sea with specialist-designed aerial torpedoes. Torpedo bombers came into existence just before the First World War, almost as soon as aircraft had been built that were capable of carrying the heavy weight of a torpedo.

Torpedo bombers carried torpedoes specifically designed for air launch. These were generally smaller and lighter than those used by submarines and surface warships. Nonetheless, since an airborne torpedo could weigh as much as 2,000lb (910kg), the aircraft carrying it needed to be specially designed for the purpose. Many early torpedo bombers were floatplanes, such as the British Short 184 (the first aircraft to sink a ship with a torpedo in 1915). Specifically the lower part of the fuselage had to be particularly strong and reinforced so that the torpedo could be carried and dropped from the aircraft’s centreline. Obviously for sheer reasons of gravity, stability, distribution of weight and equilibrium, the heavy and cumbersome torpedo was always placed under the fuselage of the bomber where its physical balance is strongest. The torpedo was fixed externally underneath the fuselage by U-shaped shackles and fitted with a release system. As can be easily imagined, a torpedo attack was a complicated task demanding calculation, rapidity, accuracy and nerves of steel. A hit depended on a good alignment of the aircraft with the target, and the release of the torpedo at the right time. In spite of sight and aiming devices, the torpedo remained a crude weapon and a torpedo attack a highly dangerous operation whose success greatly depended upon luck, inspired guesswork, experience, individual courage and personal skill. Although requiring a perilously close approach and the fact that accurate aiming was difficult and hazardous, planes armed with torpedoes were dangerous opponents. Indeed, one single lucky successful hit by a torpedo dropped from a small one- or two- seat aircraft could deliver a devastating blow to a warship in its vulnerable area, below the waterline. The ability to inflict such damage on a surface ship, no matter how great the odds of failure, made torpedo bombers important weapons that could damage, cripple or even sink a huge, costly major armoured battleship and cause the deaths of hundreds of sailors.

Early torpedo bomber (British Sopwith Cuckoo). The heavy torpedo was placed under the fuselage of the bomber between the wheels or between the floats.

Torpedo attack

For a torpedo attack launched from an aircraft there were several variables to take into account. Obviously first of all, the target had to be spotted and identified. Then, when the decision had been taken to attack and the order given, the pilot lowered the altitude and flew in the direction of the target. Speed, travel depth, salvo divergence angle (wide or narrow), all needed to be accounted for, not to mention the target’s azimuth (angular position), leading point, launch intervals and evasive movements. Before sophisticated bomb sights were introduced, and just as in dive-bombing tactics, the aircraft was the gun and the torpedo was the bullet. The pilot or the bombardier had only a very short time in which to calculate that the aircraft had reached the required position in relation to the target in order to have the right angle required for a hit. Often under heavy FlaK fire, the operator had to make a very quick estimate of the target ship’s course. In fact, he had to anticipate the future position of the target according to the speed of his own aircraft, the speed of the target and the speed of the torpedo as well as the distance between his machine and the target. Of course, the proper angle of release and the right moment for launching the torpedo were crucial. A large warship cannot turn in a small circle, so whether she turned to port or starboard at least one hit might be expected.

The best attack condition was with one or more planes on either bow of the target. Having torpedo planes approach a ship from both sides of the bow was known as the ‘Anvil Attack’ (smashing the target ‘on the anvil’), but the coordination of timing required was difficult to achieve. Furthermore, many things could go wrong with a torpedo once it was launched. Torpedoes were delicate mechanisms and, especially when dropped from a plane, they did not always run straight. The device had to be perfectly flat on the water to run true to the target. If it landed at a sharp angle, it could dive straight down; if it landed at a shallow angle, it would bounce up and down on the surface. Occasionally the torpedo would simply break up when it hit the water. If the torpedo did enter the water perfectly, it was designed to dive and then rise to a pre-set depth just below the surface. If the depth mechanism was faulty, it could cause the torpedo to run too deep and end up going underneath the target. If it did reach the target, the exploders might not trigger the bursting charge or explode it too soon. Sometimes, a slow-moving torpedo could be exploded by machine-gun fire aimed at its warhead. Even if all went well and the torpedo did actually hit the target, there was always the chance that it would be a dud and fail to explode. Although more or less accurate computing instruments and aiming bomb sights were gradually designed, a torpedo attack by a plane on a moving target was always a very risky, difficult and dangerous task.

The introduction of torpedoes in naval warfare forced the heavier ships to carry secondary armament to deal with torpedo boats before they came within effective range. Mixed armament of heavy, medium and light guns was therefore needed for a battleship in order to fight distant heavy ships and defend herself against close-range torpedo attack. From the 1930s all battleships were also equipped with numerous anti-aircraft guns in order to fend off torpedo bombers and dive-bombers.

Typical torpedo bomber attack. The schema shows the different phases of an attack: 1) approach; 2) launching the torpedo (from a distance of 1,000-1,500 yards) at a slow speed (110-180 mph) and low altitude (150-350ft); 3) position of the target when launching the torpedo; 4) anticipated position of the target; 5) torpedo trajectory; 6) fleeing the scene as quickly as possible.

Chapter 3

Early Experiments

Italy

At the beginning of the twentieth century, Italy was at the forefront of aircraft development and aerial warfare. During the colonization of Libya in 1911, Italian airmen made the first reconnaissance flight in history in October 1911 and the first bombing raid in November 1911.

In the period just before the First World War, many naval staffs began to appreciate the possibility of using aircraft to launch torpedoes against moored ships. The Italians had been among the first pioneers in the field of torpedoes in the late nineteenth century and later were also prominent in designing specialized torpedo bombers. In the restricted waters of the Mediterranean Sea the concept of combining aircraft and torpedoes was an idea with considerable promise. In 1912 an Argentinean-born lawyer and inventor called Raúl Pateras Pescara and an Italian naval captain named Alessandro Guidoni experimented by dropping weights in Venice harbour from a Farman biplane.

The Pescara-Guidoni was the first aircraft specifically designed as a torpedo bomber in 1914. It was a monoplane floatplane with a wingspan of 71ft 6in. It was powered by a Gnome 18-cylinder rotary engine of 160 horsepower.

As that available aircraft was not strong or powerful enough to carry a torpedo, Pescara and Guidoni designed their own test floatplane. In 1914, a few months before the outbreak of the First World War, the Pescara-Guidoni torpedo bomber made its maiden flight and at the same time successfully launched an 820lb torpedo, so demonstrating that the military torpedo bomber was a practical proposition.

Great Britain

For centuries Great Britain’s main defence had been organized around her navy, relying on ships to thwart and defeat invasion, and on coastal artillery. The historical flight of the Frenchman Louis Blériot over the Channel in July 1909 had demonstrated that henceforth a new threat existed. Aircraft could now cross the Channel or fly over the North Sea to attack Albion from the air.

Winston Churchill (1874–1965), as First Lord of the Admiralty from October 1911 to May 1915, was a strong proponent of naval air power. He established the Royal Naval Air Service (RNAS) in April 1912 and took flying lessons to foster aviation development. Churchill charged the RNAS with designing reconnaissance spotters and torpedo bombers for the fleet.

The British Admiralty ordered the Short Type 81 biplane floatplane as a reconnaissance aircraft. It first flew in July 1913 and was fitted aboard the cruiser HMS Hermes, which had been converted to become the Royal Navy’s first seaplane tender. When the rival Sopwith Special designed from the outset as a torpedo bomber failed to lift its payload off the water, Shorts converted the Type 81 to carry torpedoes in July 1914, just before the outbreak of the First World War.

The Short Admiralty Type S 81 was a British biplane floatplane used by the Royal Naval Air Service in the early years of the First World War. The aircraft had a maximum speed of 60 mph (97 km/h) and an endurance of five hours. It had folding wings to aid storage on ship, hence the popular name Short Folder. The floatplane had a crew of two, a length of 42ft (12.8m), a wingspan of 67ft (20.42m), and wing area of 540 sq ft (50 sq m). The aircraft was armed with one machine gun, and could carry either four 112lb (50kg) bombs or one 810lb (370kg) torpedo. Production of the Short S 81 continued until after the armistice of 11 November 1918 with a total of 936 built by several manufacturers. It served in eight navies, including the Imperial Japanese Navy which built them under licence.

United States

Although the United States had given birth to heavier-than-air flight, the US military authorities turned out slowly to respond to this new technology. By 1910 Admiral of the Navy George Dewey tasked Captain Washington Irving Chambers to investigate the possibilities of naval aviation. Over the next couple of years, Chambers initiated experiments that resulted in the first successful shipboard take-off and landing and the first successful aircraft being catapulted from a ship. At the same time, American aviator Eugene Ely, a pilot for the Curtiss firm, successfully took off in November 1910 in his Curtiss Pusher aircraft from a special platform built on the cruiser Birmingham. Then, in January 1911, Ely landed the same aircraft on the battleship Pennsylvania. The War Department created the first antecedent of the Air Force in 1907, called the Aeronautical Division Signal Corps from 1 August 1907 to 18 July 1914. It was named the Aviation Section, Signal Corps from 18 July 1914 until 20 May 1918.

The end of the Russo-Japanese War in 1905 had fuelled new theories, and the idea of dropping lightweight torpedoes from aircraft was conceived in the early 1910s by Bradley A. Fiske, a senior officer in the United States Navy. Indeed, in 1910 Fiske had even proposed defending the Philippines with a fleet of torpedo-carrying aircraft. Undaunted by the criticism of his superiors, Fiske was awarded a patent in 1912 entitled ‘Method of and Apparatus for Delivering Submarine Torpedoes from Airships’. He also defined attack tactics that included approaching the target at night so that the attacked ship would be less able to defend herself. Fiske determined that the torpedo bomber should descend rapidly in a sharp spiral to evade enemy guns. Then, when about 10 to 20ft (3 to 6m) above the water, the aircraft would straighten its flight long enough to line up with the torpedo’s intended path in the direction of the target. The aircraft would release the torpedo at a distance of 1,500 to 2,000 yards (1,400 to 1,800m) from the target and then fly away to safety. Fiske reported that using his method enemy fleets could be attacked within their own harbours provided there was enough room for the torpedo track. In the meantime other junior naval officers had received flight training, which Rear Admiral Frank Jack Fletcher put to use for reconnaissance while leading naval forces in seizing Veracruz in April 1914. Despite Fletcher’s commendation of their usefulness in the Veracruz operation, the navy’s few aircraft were obsolete by European standards when the United States entered the First World War in April 1917.

PART TWO

THE FIRST WORLD WAR 1914–18

Chapter 4

Development of Torpedo Bombers

By the outbreak of the First World War in September 1914 torpedoes and torpedo bombers were still crude and primitive machines, but the conflict presented a vast challenge and favoured the development of lots of new weapons. Torpedoes were used against shipping, mostly launched by torpedo boats and submarines.

As for the torpedo bombers they were engaged in actual combat for the first time, but their role remained extremely marginal and limited. In 1914 the torpedo bomber had no immediate strategical or tactical impact, but soon air power was beginning to make itself felt in small ways on naval thinking. The reconnaissance aircraft, the torpedo and the torpedo bomber forced ranges to open and extend because battleships dared not get so close in case they were exposed to underwater attack.

The idea of using aircraft to drop torpedoes to attack warships eventually proved sound, but aircraft engines of the period were often not powerful enough to give the required lift and impetus. As a result, only limited successes were achieved during the First World War. The torpedo bombers’ sporadic actions were without real influence on the outcome of the war at sea.

When the war ended in November 1918, all nations involved in the conflict had gained an appreciation of the capability of air power. However, the full impact and the revolutionary potential of air warfare came a generation later during the Spanish Civil War and the Second World War.

Chapter 5

Britain

The Royal Navy was at the forefront of developing torpedoes and torpedo bombers. Upon becoming First Lord of the Admiralty in October 1911, Winston Churchill enthusiastically supported the incorporation of aircraft into the navy and played a leading role in the organization of the Royal Naval Air Service (RNAS), which began as the Naval Wing of the Royal Flying Corps in 1912. The RNAS was the air arm of the Royal Navy under the direction of the Admiralty’s Air Department, and existed formally from 1 July 1914 to 1 April 1918 when it was merged with the British army’s Royal Flying Corps (RFC) to form a new service, the Royal Air Force (RAF).

As first director of the Admiralty Air Department, Captain Murray Fraser Sueter, who had earlier overseen construction of the navy’s first airship, the Mayfly, played a leading role in the development of the RNAS. Several leading naval officers also promoted the cause of naval aviation. Vice Admiral Sir John Jellicoe (commander of the Grand Fleet when Britain entered the war) was the navy’s leading proponent of airships. During the war, Jellicoe’s successor, Sir David Beatty, called for the construction of torpedo planes and aircraft carriers in order to attack German navy bases. Britain and her allies used torpedoes throughout the war. U-boats themselves were often targeted, twenty being sunk by torpedoes launched from aircraft. In July 1914 a Short seaplane piloted by Lieutenant A.M. Longmoor made a successful torpedo test drop at Calshot near Southampton. Soon British torpedo bombers, advocated by Commodore Sueter, were ordered from the Short Brothers Company at Rochester, Kent. Rapidly the new bombers saw action. The Royal Navy made its first successful torpedo attack during the Dardanelles campaign (19 February 1915 to 9 January 1916) when French, British, Australian and New Zealand troops landed in the Gallipoli peninsula.

On 12 August 1915 an RNAS Short 184 torpedo bomber floatplane piloted by Flight Commander Charles H. Edmonds sank a Turkish steamer merchantman in the Sea of Marmara. This was the first ship successfully sunk by air-launched torpedo. Edmonds was operating from seaplane tender HMS Ben-my-Chree. Five days later on 17 August 1915, Edmonds made another attack on a convoy of three Turkish vessels. One steamer was hit by a torpedo and caught fire. Another successful attack on a Turkish ship was made by Flight Lieutenant G.B. Dacre. He launched his torpedo while taxiing his floatplane in the water after engine trouble. Subsequently he managed to restart his floatplane’s engine and escape under fire from Turkish coastal batteries.

Lewis machine gun. The Lewis automatic machine gun was a First World War-era light machine gun of American design that was perfected and widely used by the British army. It was distinctive because of a wide tubular cooling shroud around the barrel and a top drum-pan magazine containing either forty-seven or ninety-seven rounds. It was commonly used as an aircraft machine gun during both world wars, almost always with the cooling shroud removed. The Lewis was gas-operated and used the British 0.30-06 Springfield cartridge. It had a rate of fire of 500 to 600 rounds per minute and an effective firing range of 880 yards (800m).

Beardmore WB VI

During the First World War Beardmore and Co. produced Nieuport 12 and Sopwith Pup aircraft under licence, and designed a ship-borne version of the Pup designated the Beardmore WB III. About 100 WB IIIs were manufactured for the RNAS. The Beardmore Company also built airships and a few aircraft of their own design, notably a single-engine, one-seat, torpedo-bomber biplane known as the Beardmore WB VI from 1918. The WB VI had an overall length of 34ft, a wingspan of 58ft and a height of 12ft 6in. Powered by one Rolls-Royce Eagle engine, it had a cruising speed of 102 mph (160 km/h) and an endurance of three hours. Armament included one torpedo. For unknown reasons the WB VI never entered production.

The Beardmore WB VI.

Short Admiralty Type 166

The Short Type 166 (manufacturer’s serial number S.90) was designed as a folding aircraft to operate from the seaplane carrier HMS Ark Royal as a reconnaissance and torpedo bomber. Six aircraft were originally ordered right before the outbreak of the First World War, followed by an order for twenty more. With a crew of two (pilot and observer/rear gunner), the Type 166 was a two-bay biplane with twin wooden pontoon floats and a water rudder fitted to the tail float, plus a stabilizing float mounted near the wingtip under each lower wing. Its length was 40ft 7in (12.38 m), wingspan was 57ft 3in (17.45 m), and its height was 14ft