page_title: Aerial torpedo
section_title: World War II
hierarchical_section_title: Aerial torpedo / History / World War II
caption_attribution_description: English: A Nakajima B5N2 Type 97 carrier attack aircraft equipped with a torpedo takes off from the Imperial Japanese Navy aircraft carrier Zuikaku on May 8, 1942 to attack United States Navy carrier forces during the Battle of the Coral Sea.
context_page_description: An aerial torpedo, airborne torpedo or air-dropped torpedo is a naval weapon, a torpedo, that an aircraft—fixed-wing aircraft or helicopter—drops in the water, after which the weapon propels itself to the target. First used in World War I, air-dropped torpedoes were used extensively in World War II, and remain in limited use. Aerial torpedoes are generally smaller and lighter than submarine- and surface-launched torpedoes.
  Historically, the term "aerial torpedo" meant flying bombs and pilotless drone aircraft used as weapons, which would today be called cruise missiles. Today, the term refers primarily to water-borne torpedoes launched from the air.
context_section_description: On the night of November 11–12, 1940, Fairey Swordfish biplane torpedo bombers of the British Fleet Air Arm sank three Italian battleships at the Battle of Taranto using a combination of torpedoes and bombs. In the course of the chase of the German battleship Bismarck, torpedo strikes were attempted in very bad seas, and one of these damaged her rudder allowing the British fleet to catch her. The standard British airborne torpedo for the first half of World War II was the 18-inch Mark XII, a 450 mm-diameter design weighing 1,548 lb (702 kg) with an explosive charge of 388 lb (176 kg) of trinitrotoluene (TNT).
  German aerial torpedo development lagged behind other belligerents—a continuation of neglect of the category during the 1930s. At the beginning of World War II, Germany was making only five aerial torpedoes per month, and half were failing in air-drop exercises. Instead, Italian aerial torpedoes made by Fiume were purchased, with 1,000 eventually delivered.
  In August 1941, Japanese aviators were practicing dropping torpedoes in the shallow waters of Kagoshima Bay, testing improvements in the Type 91 torpedo and developing tactics for the attack of ships in harbor. They discovered that the Nakajima B5N torpedo bomber could fly 160 knots (296 km/h; 184 mph), somewhat faster than expected, without the torpedoes striking the bottom of the bay 100 feet (30 m) down. On December 7, 1941, the leading wave—40 B5Ns—used the tactic to score more than 15 hits during the attack on Pearl Harbor.
  In April 1942, Adolf Hitler made the production of aerial torpedoes a German priority, and the Luftwaffe took the task over from the Kriegsmarine. The quantity of available aerial torpedoes outstripped usage within a year, and an excess of aerial torpedoes was on hand at the end of the war. From 1942 to late 1944, about 4,000 aerial torpedoes were used, but some 10,000 were manufactured during the whole war. Torpedo bombers were modified Heinkel He 111 and Junkers Ju 88 aircraft, but the Focke-Wulf Fw 190 fighter aircraft was successfully tested as a delivery system. Deficiencies in German-designed torpedoes after the capitulation of Italy in September 1943 were addressed just over a year before, through the yanagi visit of Japanese submarine I-30 in August 1942, to supply the Wehrmacht with the Type 91 torpedo's technology and blueprints, to be made in Germany itself as the Lufttorpedo LT 850.
  The Mark 13 torpedo was the main American aerial torpedo, yet it was not perfected until after 1943 when tests showed that it failed in 70 percent of the drops made from aircraft traveling faster than 150 knots (280 km/h; 170 mph). Like the Japanese Type 91, the Mark 13 was subsequently fitted with a wooden nose covering and a wooden tail ring, both of which sheared off when it struck the water. The wooden shrouds slowed it and helped it retain its targeting direction through the duration of the air drop. The nose covering absorbed enough of the kinetic energy from the torpedo hitting the water that recommended aircraft height and speed were greatly increased to 2,400 feet (732 m) high at 410 knots (760 km/h; 470 mph).
  In 1941, development began in the United States on the FIDO, an electric-powered air-dropped acoustic homing torpedo intended for anti-submarine use. In the United Kingdom, the standard airborne torpedo was strengthened for higher aircraft speeds to become the Mark XV, followed by the Mark XVII. For carrier aircraft, the explosive charge remained 388 lb (176 kg) of TNT until later in the war when it was increased to 432.5 lb (196.2 kg) of the more powerful Torpex.
  During World War II, U.S. carrier-based torpedo bombers made 1,287 attacks against ships, 65% against warships, and scored hits 40% of the time.  However, the low, slow approach required for torpedo bombing made the bombers easy targets for defended ships; during the Battle of Midway, for example, virtually all of the American torpedo bombers—nearly all of the obsolete Douglas Devastator design—were shot down by the Japanese.
caption: A Japanese Nakajima B5N2 torpedo bomber takes off from the aircraft carrier Zuikaku  during the Battle of the Coral Sea.
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