The Pacific War can be described as the battle of the gods of aircraft carriers, aircraft carrier aircraft replaced the battleship's heavy guns to become the most decisive weapon on the sea battlefield, even if the armored cannons are as strong as the battleship "Yamato", they finally helplessly sank under the repeated violent beatings of the US carrier-based aircraft and were buried in the sea. During world war II, carrier-based aircraft and shore-based aircraft attack ships mainly rely on air bombs and air torpedoes, two weapons, because torpedoes attack the hull under the water line of the target, will directly destroy the watertightness and balance of the hull, resulting in the devastating consequences of water capsizing, and it is generally believed that air torpedoes are more lethal than bombs.
■ The Royal Navy's Cuckoo torpedo aircraft during World War I projected aviation torpedoes.
In the period of World War II, aviation torpedoes are absolutely cutting-edge military technology, even if the invention of torpedo weapons has been more than half a century, only a few countries can make torpedoes (even now, even fewer countries than those who have mastered missile technology), and there are very few countries that can develop and equip air torpedoes, only Britain, the United States, Japan and other naval powers, even Germany, which invented early self-guided torpedo technology, has not been able to overcome the difficulties of air torpedoes, and has to turn to allies Japan and Italy.
■A painting depicting the British Swordfish torpedo air raid on the German battleship Bismarck in May 1941.
Technically, air torpedoes are more difficult than naval torpedoes because of the harsher conditions and technical requirements of air torpedoes. Different from ordinary torpedoes, aviation torpedoes are launched from high-speed flying aircraft, usually from tens of meters or even hundreds of meters into the sea from the air, not only to consider the operating state of the torpedo in the water, but also to take into account the flight attitude in the air, and at the moment of entering the water to withstand the violent impact, by the dual influence of inertia and gravity, the depth of diving after entering the water is greater than that of the ship, to withstand greater water pressure, so the air torpedo must have a stronger structural strength and more effective attitude control capabilities, There are also more technical challenges that need to be solved. Japan and the United States, which had the highest level of air torpedoes during World War II, were each equipped with a kind of air torpedo, namely the Type 91 torpedo and the Mk 13 type torpedo, which both matured after repeated improvements and achieved good results in actual combat.
■ Painting of a torpedo attack by a Luftwaffe He 111 bomber during World War II.
Type 91 aviation torpedoes
The development of the Japanese aviation torpedo began in 1923 when The Naval Administration Headquarters member Captain Masaji Naruse went to Britain to investigate torpedo technology, submitted a detailed technical report after returning to China, and on this basis formed a technical team headed by Captain Naruse, and began the development of the domestic aviation torpedo in 1928, after several years of research, it was finalized and put into production in 1931, named the Type 91 torpedo, that is to say, ten years before the outbreak of the Pacific War, the Japanese Navy officially installed this kind of attack ship weapon.
■The type 91 aviation torpedo, which was preserved to this day, was finalized and put into operation in 1931.
The Type 91 aviation torpedo is 450 mm in diameter, 5.27 m long, weighs 784 kg, has a warhead charge of 149.5 kg, is driven by an 8-cylinder star-piston engine, has a range of 2000 meters at 42 knots, and can also be adjusted to a low speed of 36 knots, with an extended range of 3000 meters. However, the early models of the Type 91 torpedo were not yet truly practical, there were problems such as fragile structure and poor reliability, and they were always in a state of use and modification after installation, and in fact, the improvement work continued until the end of World War II. Due to performance limitations, the Type 91 torpedo was initially only able to be projected at low altitude and low speed, but the early attack aircraft of the Japanese Navy were low-speed and low-altitude biplanes with good performance, and were regarded as excellent air-launched torpedo platforms.
■ Japanese Navy Type XIII shipboard attack aircraft drop Type 91 aviation torpedoes.
With the advent of faster attack aircraft, the performance of aviation torpedoes has been required to be increased accordingly, and they can be projected at higher altitudes and faster speeds. In 1936, the Naval Aviation Technology Plant designed a wooden stabilizer wing, installed in the tail of the torpedo to improve stability in the air, and the stabilizing wing would fall off on its own under impact when the torpedo entered the water. This stabilizer wing is known as the "frame plate" within the Japanese Navy, and is divided into two forms, cross type and box type, depending on the type of aircraft used (single-engine ship attack or twin-engine land attack). The torpedo with the frame plate is called the Jiuyi type, and since then the frame stabilizer wing has become the standard of various variants. It is worth noting that many literature and film and television works regard the wooden stabilizing wing as the reason for the shallow water launch of the Japanese torpedo at the time of the Pearl Harbor attack, which is a widely spread error, and its role is only to improve the stability of the flight attitude, and it is detached when entering the water, which has no obvious effect on shortening the depth of torpedo settlement.
■ A replica of the wooden stabilizer wing of the Type 91 aviation torpedo, known to the Japanese Navy as the "frame plate".
The 1938 type 91 was introduced in 1938 with the enhancement of the mine-body structure, the extension of the minehead, and the increase in charge to 204 kg, although its most important improvement came on the eve of the Pacific War. In the test, the Japanese Navy found that after the projection speed exceeded 330 km / h, the torpedo failure rate increased significantly, and after entering the water, the problem of diving too deeply, propeller damage, heading deflection, reverse navigation and even self-detonation occurred, and after a large number of observations, it was concluded that the torpedo was caused by the rolling at high speed, and it was considered extremely difficult to suppress the roll at that time, plus the Japanese Navy was working on the development of air-launched oxygen torpedoes (Type 94 torpedoes), and the improvement of the Type 91 torpedo was once stagnant.
■ The Type 91 torpedo type II was equipped with a roll stabilizer, improved the attitude control of the torpedo, and realized shallow water lightning strikes.
However, the development of the Type 94 torpedo failed to make progress, and the Pearl Harbor operation urgently needed shallow water torpedoes, the Naval Air Technology Plant could only carry out emergency research, in August 1941 developed the roll stabilizer, which is a precision instrument composed of gyroscopes and air valves, by feeling the attitude change to manipulate a pair of stable rudders installed in the rear of the mine body to adjust, so that the torpedoes remain in a stable posture, and can play a role in the air and underwater, not only improving the stability of the operation of the torpedo, Moreover, the depth of settlement is reduced from 60 meters to 20 meters, and combined with the ultra-low altitude flight of elite pilots, the depth of settlement can be controlled at 10 meters, thus achieving shallow water lightning strikes, which is the truth of the shallow water torpedo at Pearl Harbor. Before the outbreak of war, the Mitsubishi Nagasaki Arsenal urgently produced 100 Type 91 torpedoes equipped with rolling stabilizers, becoming the number one killer of the US Pacific Fleet!
■ The most famous photograph of the Type 91 aviation torpedo, the modified Type II torpedo placed on the deck of the Akagi before the attack on Pearl Harbor.
■ The Type 97 naval attack carrying the Type 91 air torpedo took off from the deck of the aircraft carrier.
■ The wreckage of the Japanese 97 ship attack and its main weapons: the Type 91 torpedo and the 800 kg armor-piercing bomb on display in the Pearl Harbor Museum of History.
The Type 91 torpedo, which was put into use in 1942, integrated wooden frame plates and rolling stabilizers, increased the charge of the minehead to 235 kg, enhanced the power, increased the weight to 848 kg, became the most used aviation torpedo by the Japanese army in the war, and inflicted heavy casualties on Allied ships in previous naval battles such as the Indian Ocean Operation, the Battle of coral sea, the Battle of Midway, and the Battle of the South Pacific. Because the aviation oxygen torpedo has never been finalized, the Japanese Navy can only continue to improve on the basis of the 91-type torpedo, and has introduced a variety of modifications, such as strengthening the minehead structure, using a new frame plate, increasing the charge, etc., and the final Type 91-5 charge increased to 420 kg, the weight increased to 1080 kg, but the range speed was reduced to 1500 m/41 knots. However, by the end of the war, the US military had mastered the air superiority of the battlefield, the success rate of Japanese aircraft in carrying out lightning strike missions was almost zero, and the Type 91 aviation torpedo basically lost the opportunity to appear.
■ Painted: The 97-Ship Attack with the Type 91 Aviation Torpedo, the most powerful combination of weapons in the Pacific Theater at the beginning of the war.
■ In February 1945, the ground staff of the Shore-based Air Force of the Japanese Navy was installing type 91 torpedoes for the type 1 land attack, and the success rate of the lightning strike mission was almost zero at this time.
Mk 13 air torpedo
The U.S. Navy began experiments with air-launched torpedoes as early as 1920, and the original air torpedoes were converted from the ship's 450 mm Mk 7 torpedo. In 1925, the U.S. Navy launched the G-6 program for the development of special air torpedoes, but due to the HNA force's preference for more accurate dive bombing, the expectation of aerial torpedo attacks was not high, and the research and development work was intermittent, until the first test launch was carried out in 1932, and finally officially entered service in 1938, named the Mk 13 torpedo, which was also the first specially designed aerial torpedo of the U.S. Navy.
■ Photographs of the U.S. Navy conducting early air-dropped torpedo tests, using a modification of the Mk 7 torpedo.
The Mk 13 is very different from the air torpedoes of other countries of the same era, instead of adopting the mainstream 450 mm caliber, but choosing a 570 mm caliber that exceeds the naval torpedo, the initial model length is only 4.089 meters, the shape is thick and short, the weight is 884 kg, the minehead charge is 182 kg TNT, the speed is only 30 knots, but the range can reach 5210 meters! The early production of the Mk 13 torpedo and the same period of American ship torpedoes have serious technical defects, the reliability is very low, can only be launched at an altitude of less than 20 meters and a speed of less than 200 km / h, and it is difficult to start or sail normally after entering the water, in the July 1941 exercise VT-6 squadron projected 10 torpedoes, only 1 normal operation, 5 deviations, 4 direct sinking!
■ U.S. Navy Mk 14 naval torpedo (top) versus Mk 13 air torpedo (bottom), which is short and thick.
At the outbreak of the Pacific War, in addition to the range, the Mk 13 torpedo in addition to the range, other combat technical indicators and actual combat performance are far inferior to the opponent's Type 91 torpedo, coupled with the U.S. Navy's emphasis on low-altitude and low-speed lightning strike tactics, so that the early stage of the war the U.S. military aviation torpedo attack can only be described in tragic words, especially in the Battle of Midway, 42 of the 51 torpedo planes were shot down, but not even a single torpedo hit, and all 4 Japanese aircraft carriers were chartered by dive bombers! Even by 1943 the problem of the Mk 13 torpedo had not been effectively solved, and a survey in mid-1943 showed that 36% of the 105 torpedoes thrown at speeds above 280 km/h failed to start, 20% sank, 20% were yawed, 18% were inaccuracies, 2% were glided on the surface of the water, only 31% were operating normally, and the failure rate reached 100%!
■ Before the war, the US Navy TBD torpedo aircraft conducted mine-throwing training.
■ A painting depicting the massacre of a squadron of VT-8 torpedo aircraft during the Battle of Midway.
Faced with reports of loss of confidence in torpedoes by frontline troops, the U.S. Naval Ordnance Department went all out to promote improvements, commissioning caltech to conduct a systematic study of the fluid dynamics of torpedoes, repeatedly projecting torpedoes on a lake, and recording changes in posture at high speed photography to analyze the causes of the problem. After more than 4,300 tests, the experts came up with a package solution. First of all, the early low-altitude low-speed mine-throwing method was abandoned, and the high-speed mine-throwing was changed to a small angle of 26 to 30 degrees to dive high-speed mine-throwing to ensure air stability and the best water entry angle; secondly, three accessories were added to the torpedo to improve attitude control and stability, a sleeve-shaped resistance ring was installed on the minehead, reducing the air speed and playing a shock absorption role when entering the water, using a box-type stabilizer wing similar to the Japanese "frame plate" to improve flight stability, and finally installing a ring guard on the tail of the torpedo to improve the fluid performance of the torpedo in the water. Ensure smooth sailing.
■This schematic diagram shows the Mk 13 torpedo with a head resistance ring and box stabilizer wings.
■ In October 1944, on the flight deck of the USS Wasp, ground crews prepared to load the TBM torpedoes with Mk 13 torpedoes, and accessories had been installed on the torpedoes.
After testing the above-mentioned attachments with obvious effects, the US military quickly manufactured in large quantities in the country, shipped to the front line for the troops to modify the existing torpedoes, and also made more detailed technical modifications, resulting in at least 13 variants, and the weight of the Mk 13 torpedo produced later increased to 1005 kg. The length was 4.19 m, the charge was changed to 275 kg of high-energy explosives, the speed was increased to 33.5 knots, the range was 5760 m, and more importantly, the firing conditions of the torpedo were greatly relaxed, and it could be projected from an altitude of 730 m at a high speed of 760 km / h, greatly exceeding the Japanese torpedo, the latter with a maximum height limit of 200 m and a maximum speed limit of 454 km / h. In early 1945, the U.S. Navy even conducted a high-altitude mine-throwing test, dropping 6 Mk 13 torpedoes from an altitude of 2100 meters, of which 5 were operating normally!
■ A painting depicting the TORP torpedoes thrown by a US TBF torpedo plane braving anti-aircraft artillery fire.
■ During the Battle of Okinawa in 1945, the Mk 13 torpedo stored on the US land airfield was painted with a shark's beak pattern on the resistance ring.
After improvements, the Mk 13 torpedo finally became an effective combat weapon in 1944, shining brightly in the naval battles of the late war, which greatly caused the Japanese Navy to suffer greatly, and the Mk 13 torpedo was best known for sinking 2 Yamato-class battleships known as "unsinkable battleships", in the Battle of the Sibuyan Sea on October 24, 1944, Musashi was hit by 19 torpedoes and buried at the bottom of the sea, and in the Okinawa special attack on April 7, 1945, "Yamato" The trumpet also ate 10 torpedoes, capsized and sank! According to statistics, in World War II, the US Navy carrier-based aircraft fired a total of 1287 Mk 13 torpedoes, achieving 514 hits, with a hit rate of up to 40%, of which 50% of the torpedoes hit the Japanese aircraft carriers and battleships, which can be called a giant ship killer! When the war ended in 1945, the U.S. Navy evaluated the Mk 13 torpedo very differently than it had at the time of the war, considering it the best aero torpedo in the world, and continued to serve until 1951!
■ The scene of the battleship Yamato being hit by a U.S. torpedo in the film "The Battle of Archimedes".
■ The Mk 13 torpedo, preserved in the museum today, shows the circular shield of the tail of the torpedo.