Torpedo bomber

A torpedo bomber is a bomber aircraft designed primarily to attack ships with aerial torpedoes, but which could usually also carry out conventional attacks using bombs. Torpedo bombers came into existence just before the First World War almost as soon as aircraft were built that were capable of carrying the weight of a torpedo, and remained an important type of aircraft until the 1950s when the role devolved to conventional bombers, and later taken over by anti-ship missiles in part due to their vulnerability in making an attack. During World War II they were an important element in many famous battles, notably the British attack at Taranto and the Japanese attack on Pearl Harbor.

Types
Torpedo bombers first appeared immediately prior to World War I. Generally, they carried torpedoes specifically designed for air launch, that were smaller and lighter than those used by submarines and surface warships. Nonetheless, as an airborne torpedo could weigh as much as 2000 pounds (or 907 kilograms), more than twice the bomb load of contemporary single-engined bombers, the aircraft carrying it usually needed to be specially designed for the purpose. Many early torpedo bombers were floatplanes, such as the Short 184 (the first aircraft to sink a ship with a torpedo), and the undercarriage had to be redesigned so that the torpedo could be dropped from the aircraft's centerline.

While most torpedo bombers were single engine aircraft, some multi-engined aircraft have also been used as torpedo bombers, with the Mitsubishi G3M Nell and Mitsubishi G4M Betty being used in the Sinking of Prince of Wales and Repulse.

Some postwar jet aircraft (such as the Ilyushin Il-28T) were adapted as torpedo bombers in the late 1940s and 1950s. The last known torpedo bomber attack was made by U.S. Navy Skyraiders against the Hwacheon Dam during the Korean War. The North Korean Air Force finally retired the world's last operational torpedo bombers in the 1980s.

In a parallel development, many maritime strike aircraft and helicopters have been capable of launching guided torpedoes, however, these are not normally used against surface vessels, but primarily against submarines and are not generally referred to as torpedo bombers.

History
Many naval staffs began to appreciate the possibility of using aircraft to launch torpedoes against moored ships in the period before the First World War. Experiments in dropping weights by an Italian naval captain Alessandro Guidoni in 1912 from a Farman MF.7 Longhorn led to the first successful air launch of a torpedo. Admiral Bradley A. Fiske of the US Navy in 1912 took out a patent for a torpedo carrying aircraft entitled “Method of and apparatus for delivering submarine torpedoes from airships.” He suggested that aircraft would attack at night.

Winston Churchill, as political head of the Royal Navy, First Lord of the Admiralty, from October 1911 to May 1915 was a strong proponent of naval air power and established the Royal Naval Air Service in April 1912 and took flying lessons, to foster aviation development. Its first task: to design reconnaissance spotters and torpedo bombers for the Fleet.

First Torpedo Bombers
The British Admiralty ordered the Short Type 81 biplane floatplane as a reconnaissance aircraft. It first flew in July 1913 and was loaded 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, Short`s converted the Type 81 to carry torpedoes in July 1914 – just before the outbreak of the First World War.

The first plane designed from the outset as a torpedo bomber the five seat floatplane biplane AD Seaplane Type 1000 or AD1 however it proved to be a failure. When the prototype built by J. Samuel White from the Isle of Wight first flew in June 1916 it was found to be too heavy and its float struts too weak for operations. Remaining orders were cancelled.

First World War
On August 12, 1915 a Royal Naval Air Service Short 184 torpedo bomber floatplane sank a Turkish merchantman in the Sea of Marmara. It was operating from HMS Ben-my-Chree a seaplane carrier converted from a ferry. Fitted with an aircraft hangar, it was used to carry up to six biplanes with their wings folded back to reduce carrying space. This was the first ship successfully sunk by air-launched torpedo. Five days later another ship supplying Turkish forces on the Gallipoli Peninsula against British, Australian and New Zealand troops was also sunk.

Production of the Short 184 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. The first torpedo bomber designed for operation from aircraft carriers was the Sopwith Cuckoo. First flown in June 1917, it was designed to take off from the Royal Navy`s new aircraft carriers, but had to land on an airfield as arrester wires, needed to stop an aircraft during landing on a ship, had not yet been perfected. The Admiralty planned to use five carriers and 100-120 Cuckoos to attack the German High Seas Fleet, which had been sheltering in Kiel since the Battle of Jutland in 1916. When the war ended only 90 Cuckoos were complete, however.

Interwar Years
Of the major maritime nations, only Britain, Japan and the US developed carrier-borne torpedo bombers, after hostilities ceased in Europe. Initially Japan purchased both ships and aircraft from Britain as the Imperial Japanese Navy modelled itself on the Royal Navy. Of the three, only Britain and Japan also perceived a need for land-based torpedo bombers though a number would be developed by other countries. Bordered by oceans against any possible foe, the US ignored landplane torpedo bomber development.

The Vickers Vimy twin engine heavy bomber was designed to bomb German cities in retribution for German air attacks on England. It reached squadrons in France too late to play a role in the First World War. Had war continued it would have been deployed as a torpedo bomber.

The first landplane specifically designed as a torpedo bomber was the Hawker Horsley. By the mid-Thirties the torpedo bombers that would start the Second War were being deployed. The Fairey Swordfish flew first in 1934, the Douglas TBD Devastator and Mitsubishi G3M (Nell) in 1935 and the Nakajima B5N (Kate) and Bristol Beaufort a year after that

Second World War
In the early hours of 13 June 1940 two Beauforts found the German cruiser Lützow off Norway. The first was mistaken for a Junkers Ju 88 and was able to torpedo the Lutzow without return fire, putting her out of action for six months. The second was shot down by defending Messerschmitt Bf 109s. Eight days later nine Beauforts attacked the German battlecruiser Scharnhorst off Norway. As aerial torpedoes were unavailable they dropped 500 lb bombs. No hits were scored and defending Messerschmitt Bf 109s downed five.

Even before the outbreak of World War II, the Royal Navy had studied the threat in the Mediterranean posed by the Italian fleet. This had its advance base in the new port of Taranto in the heel of Italy. Captain Arthur Lyster of the aircraft carrier HMS Glorious proposed that its Fairey Swordfish torpedo bombers could launch a night attack against Taranto. At that time the Royal Navy was the only force in the world with this capability. The Swordfish, a three seat biplane looked outmoded but its low stall speed made it an ideal platform for launching torpedoes into the shallow waters of Taranto. The torpedoes were adapted with wire cables attached to their nose and wooden fins at their tail to slow their fall and make a shallow impact with the water, which was only 39 ft deep. On the night of 11 November 1940, 21 Swordfish left the new aircraft carrier HMS Illustrious. Some carried bombs and flares but the main force carried torpedoes. British decoy maneuvers and a lack of radar allowed the British to surprise the ill-prepared Italian fleet at anchor in Taranto. Three battleships were put out of action, half of the Italian fleet, for the loss of two Swordfish. Two airmen were killed and two others captured. The next day the remaining battleships withdrew to Naples ceding control of the Mediterranean to the British.

Pearl Harbor had an average depth of just 42 feet, a little more than Taranto. So the Imperial Japanese Navy took a very keen interest in the British victory at Taranto. The naval attaché in Berlin visited the harbour. The Japanese Government asked their Axis partner, Nazi Germany, to provide intelligence on Pearl Harbor. The German Abwehr asked their Yugoslav agent Dusan Popov to travel to Hawaii to prepare a report. Unbeknownst to the Germans Popov was a double agent working for the British under the code name Tricycle. British Intelligence sent Popov to meet the head of the FBI J. Edgar Hoover in Washington with a long list of questions, and the suggestion that he should travel to Hawaii and provide false data just as he did three years later for the D-Day Normandy landings. Hoover dismissed him from his office.

On 6 April 1941, a single Bristol Beaufort piloted by Flying Officer Kenneth Campbell attacked the German battleship Gneisenau in Brest harbour in Brittany where she and her sister ship, the Scharnhorst were sheltering beneath a massive array of anti-aircraft guns. The other five Beauforts on the mission failed to rendezvous due to bad weather. Campbell received a posthumous Victoria Cross for launching his solo torpedo which put the Gneisenau out of action for six months.

On 26 May 1941 three Fairey Swordfish were launched from the Royal Navy`s carrier HMS Ark Royal. They found the German battleship Bismarck in the Eastern Atlantic battling a fierce gale. With the battleship`s bow pitching up and down 60 ft in 80 mph winds, the Swordfish had to release their torpedoes into the troughs of waves to ensure they would run properly. Two torpedoes hit, the one fired by John Moffat hitting the rudder of the Bismarck and jamming it so severely that the huge ship could only turn helplessly in wide circles. Later that day battleships and destroyers of the Royal Navy cornered her, and Bismark's crew scuttled her after sustaining severe damage from heavy gun fire and more torpedoes.

Admiral Isoroku Yamamoto`s fleet of six carriers was carrying 40 Nakajima B5N2 Kate torpedo bombers as well as dive bombers on Sunday December 7, 1941, when it arrived at its launching point north of Hawaii. The Japanese struck the US Pacific Fleet. The torpedo bombers, in a coordinated attack with dive bombers, sunk or damaged all eight of the battleships which they found moored in Pearl Harbor. The Japanese had studied the attack on Taranto and had practiced dropping specially modified torpedoes in the shallow waters of Japan`s Inland Sea. Only five Kates were lost in the attack. In later months torpedo bombers were responsible for the sinking of the US aircraft carriers Lexington, Yorktown and Hornet.

Three days later Admiral Sir Tom Phillips was returning to Singapore on board the new battleship HMS Prince of Wales, after an unsuccessful attempt to impede Japanese landings in Malaya. His fleet included the First World War battle-cruiser HMS Repulse and should also have had the new aircraft carrier HMS Indomitable, with a squadron of Sea Hurricanes. But the carrier was delayed for repairs after running aground in the harbour at Kingston, Jamaica.

Eight Mitsubishi G3M Nell twin engine level bombers and 17 Nell torpedo bombers found the two capital ships without air cover in broad daylight. They scored just a single bomb hit on the Repulse and a single torpedo hit on Prince of Wales. The torpedo struck where the outer port propeller shaft exited the hull and Prince of Wales took on 2,400 tons of water through a ruptured stern gland. The battleship listed 12 degrees to port preventing the starboard side 5.25 inch anti-aircraft guns from depressing low enough to deter more torpedo bombers.

A second squadron, this time of Mitsubishi G4M Betty torpedo bombers now attacked both ships. Repulse had dodged 19 torpedoes by skillful steering but now G4Ms attacked the bow from both sides and scored another hit. At about this point Repulse radioed for defensive fighters A squadron of 10 Royal Australian Airforce Brewster Buffalos arrived an hour later to watch Prince of Wales sink. Repulse had already sunk. Each ship had been hit by four torpedoes out of 49 fired. The Japanese lost four aircraft. Neither G3Ms nor G4Ms carried defensive armament, which had been stripped to extend their range. The presence of modern allied fighters to defend the two capital ships might have led to a different outcome.

On 12 February 1942, Bristol Beauforts were dispatched to intercept the German cruiser Prinz Eugen off Trondheim, Norway. Prinz Eugen had accompanied the Bismarck into the Atlantic but escaped back to Brest, to fight again. For the first time the Beauforts were accompanied by Bristol Beaufighters and Bristol Blenheims. In a new RAF tactic the Blenheims acted as decoys making pretense torpedo runs while the Beaufighters, a development of the Beaufort fitted with four 40mm cannons shot up the anti-aircraft gunners. This was intended to give the Beaufort a clear torpedo run. Despite the use of 28 Beauforts, no torpedoes hit and three aircraft were lost.

The US Navy`s standard torpedo bomber in 1942 was the Douglas TBD Devastator first flown in 1935 and embarked on carriers of the Pacific Fleet in 1937. On 7 May 7 1942 in the Battle of the Coral Sea, Devastators sank the Japanese aircraft carrier Shōhō but failed to sink the Shokaku the next day.

At the Battle of Midway on 4 June 1942, 41 Devastators launched from three US carriers failed to score a single torpedo hit and only six aircraft returned. The rest fell to defending Mitsubishi A6M Zeros and anti-aircraft fire. The attacks had been poorly coordinated but the Devastator was immediately withdrawn from front-line service.

The successor to the Devastator, the Grumman TBF Avenger arrived too late at Pearl Harbor to be loaded onto carriers for the Battle of Midway. However six were flown from Midway Island airbase. They fared no better with five lost without a single hit.

Avengers were more successful as tactics improved and crews became more skilled. On 24 August 1942, 24 Avengers sank the light carrier Ryujo at the Battle of the Eastern Solomons. At Guadalcanal, Avengers from the Navy and Marine Corps finished off the battleship Hiei which had been damaged the night before.

Beauforts also had more success when they moved to Malta to attack Italian warships and transport. Flying Officer Arthur Aldridge discovered a convoy guarded by the Heavy Cruiser Trento early on June 14, 1942 some 200 miles East of Malta. As with the attack on the Lutzow, his plane was taken for a Junkers Ju 88 and he hit Trento with his torpedo: the ship eventually being finished off by the submarine HMS Umbra, which was close by.

Action continued in the Pacific, where the last notable torpedo bomber attack took place on April 7, 1945. Avengers from Yorktown were searching between Okinawa and Honshu for the Japanese battleship Yamato, which was escorted by cruisers and destroyers. Her mission was to run aground on Okinawa to provide floating heavy artillery for the defending troops in the expected Allied seaborne invasion. Her 18.1 inch guns could have created havoc among frail landing craft. Yamato and her sister Musashi were the largest, most powerful battleships in the world. Planned in great secrecy, they had been designed to take on three US battleships each and win.

The squadron led by Lieutenant Tom Stetson found the cruiser, which was the prime target, already sinking so six planes were detached to attack the Yamato, instead. One in which Frederick E. Wicklund was the tail gunner and radar/radio operator became detached from the formation whilst climbing in heavy cloud cover. The pilot Lieutenant Grady Jean asked each crewman in turn if they wished to make a solo attack, which was likely to prove suicidal The crew referred the decision to the skipper, who deftly dodged anti-aircraft fire and 18 inch shell splashes from Yamato`s big guns  to release their torpedo.

Wicklund had recalled a briefing that Yamato had torpedo blisters to a depth of 22 feet, so he crawled back in the fuselage to reset the torpedo`s running depth from the 10 feet preset for the cruiser to 23 feet. He later explained that he heard no command to do this and doubted whether the other five planes had done so. In this case their torpedoes would have exploded harmlessly against the blisters. A crewman snapped the explosion, in which debris rose to their altitude of 300 feet. Possibly a torpedo had hit the fuel storage. Yamato rolled over and sank, with the loss of 90 percent of the crew. The Yorktown lost ten planes and twelve aircrew. All pilots involved in the attack were awarded the Navy Medal and every crewman the Distinguished Flying Cross.

Obsolescence and replacement
Torpedoes travel under water at around 40 knots, a speed easily matched by a destroyer. Fast battleships could make 32 knots. So it was possible for a skilful captain to evade a torpedo: HMS Repulse dodged 19 before Japanese torpedo bombers attacked simultaneously from both forward quarters. A rocket travelling at 1,000 mph was another matter. The first air-launched rockets were fired by the French and British flying Nieuport 11s equipped with Le Prieur rockets to shoot down German observation balloons over the Western Front in 1916. Except in the Soviet airforce the idea was largely forgotten until early 1941, when the Desert Air Force found its aircraft to be impotent against the Panzers of Erwin Rommel`s Afrika Korps. Henry Tizard Chief Scientist to the British Government formed a panel of experts. The British Army had used rockets to fire against low-flying bombers during the Battle of Britain and by enlarging the tube from 2 inches to 3 inches and fitting first a 28 pound and then a 60 pound high explosive warhead, a new weapon was quickly developed. Russian assistance was requested as they were already using rockets against German tanks, but in spite of receiving a gift of Hawker Hurricanes none was given. The British fitted them initially to Hurricanes in June, 1942 in time to deploy them against Rommel`s tanks.

On May 23, 1943 a Fairey Swordfish destroyed U752 in the Atlantic and five days later a Lockheed Hudson of RAF Coastal Command destroyed another in the Mediterranean. These rockets were fitted with iron spikes and fired at a shallow angle into the sea. Once under water, they curved upwards and punctured the hull below the waterline, making it impossible for a submarine to submerge. A new era in aircraft attacks on ships had been initiated. Caltech developed the 5 inch High Velocity Aircraft Rocket better known as Holy Moses with a 24 pound warhead for the US Navy. It was rushed to Europe for use from D-Day and later used by most Navy planes in the Pacific.

Barnes Wallis deputy chief aircraft designer at Vickers spent much time thinking about weapons that might shorten the war. He conceived his “Spherical Bomb, Surface Torpedo” after watching his daughter flip pebbles over water. Two versions were developed, The smaller Highball was to be used against ships and attracted essential British Admiralty funding for his project. A 1280 lb flying torpedo, of which half was Torpex torpedo explosive, it was developed specifically to sink the Tirpitz which was moored in Trondheim fjord behind torpedo nets. However development delays meant that another Barnes Wallis invention, the 5 ton Tallboy was used instead. Two dropped by Avro Lancasters from 25,000 ft hit at supersonic speed and capsized the Tirpitz on November 12, 1944. The larger version, codenamed "Upkeep", was used to destroy the Mohne and Eder dams by Lancasters from the specially recruited and trained 617 Squadron of the RAF, often known as the Dambusters, under Wing Commander Guy Gibson.

Tactics
One crucial limitation of a torpedo bomber was that it had to fly a long, straight course at a constant altitude of 30 metres (100 ft) toward the target ship before launching its torpedo. The torpedoes were very sophisticated weapons and were prone to damage when landing on water, especially on a wave; they were ideally aimed at the bottom of a wave but this was difficult in practice.

During a torpedo run, the attacking aircraft were easy targets for defending fighters from a combat air patrol. Furthermore, torpedo planes were also highly vulnerable to anti-aircraft fire, particularly the heavy anti-aircraft guns (such as the 5 inch DP) which fired into the water, creating water spouts to slap the torpedo planes.

In the 1930s, the Japanese Navy developed the best way for torpedo bombers to achieve a hit. They used an "anvil attack" in which two groups of torpedo planes approached the target ship's bow at an angle of about 45 degrees, one on each side of the ship. The torpedoes were to be launched at the same distance from the ship; this would have ensured a hit no matter where the ship tried to maneuver. In practice, this kind of attack was difficult to coordinate and therefore extremely rare. Usually, combat air patrols and anti-aircraft fire quickly broke up approaching plane formations, after which each aircraft was on its own. At Pearl Harbor attack the ships were lined up and basically stationary so the Japanese first attack wave of 40 torpedo bombers of the Imperial Japanese Navy (IJN) armed with Type 91 torpedoes, out of 183 planes, were able to hit the ships broadside with torpedoes as the defenders were caught by surprise.

Torpedo bombers were best used as part of a coordinated attack along with other types of aircraft. For instance, during the attack on the battleship Yamato, fighter planes strafed the ship with machine guns to suppress its anti-aircraft gun fire, while dive bombers tried to cause havoc and cause topside damage, thus leaving the torpedo bombers unmolested so they could make their attack runs. By contrast, if the attackers failed to achieve air superiority or surprise, torpedo bombers would suffer heavy losses regardless of whether the type was obsolete or not. This is best exemplified at the Battles of Midway where the Air Group Eight's dive bombers missed the Japanese carriers. So Torpedo Squadron 8 (VT-8, from Hornet), led by LCDR John C. Waldron sighted the enemy carriers and began attacking without any coordination with the dive bombers or fighter cover. It was followed by Torpedo Squadron 6 (VT-6, from Enterprise).[68] Without fighter escort, every TBD Devastator of VT-8 was shot down without being able to inflict any damage, with Ensign George H. Gay, Jr. the only survivor. VT-6 met nearly the same fate, with no hits to show for its effort. The Japanese combat air patrol, flying the much faster Mitsubishi A6M2 "Zeros", made short work of the unescorted, slow, under-armed TBDs torpedo bombers. A few TBDs managed get within a few ship-lengths range of their targets before dropping their torpedoes. Also at the Santa Cruz; the Nakajima B5N Kate despite being in service since 1935 played a key role in sinking USS Hornet, while the brand-new TBF Avenger torpedo bomber's failed to hit a fleet carrier.

When the targets were ships able to maneuver at high speed and hence much harder to hit, torpedoes proved less effective, except in cases when the crews launching them were especially well trained. Still, even a single torpedo hit on an enemy warship could cripple it decisively, especially in the case of vessels without an armored belt (cruisers and aircraft carriers often had torpedo blisters but these were not as extensive as that of battleships). Even heavily armored battleships did not have their protective belt extending to the bow, and a hole made there could be wrenched wider from the pressure of the inrushing water which could buckle and crush bulkheads; this tactic was used against the Yamato super-dreadnought. Also, there was nothing to protect the rudder and propellers at the stern, which was demonstrated during the hunt for the Bismarck and Force Z.

Notable torpedo bomber pilots

 * Charles T. Beaird
 * Kenneth Campbell VC
 * Charles Edmonds
 * Eugene Esmonde
 * George H. W. Bush
 * Mitsuo Fuchida
 * George H. Gay, Jr.
 * John C. Waldron
 * John Kelvin Koelsch
 * Ulvert M. Moore
 * John Moffat
 * Carlo Emanuele Buscaglia