An aerial torpedo (also known as an airborne torpedo or air-dropped torpedo) is a torpedo launched from a torpedo bomber aircraft into 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.
History
Origins
The idea of dropping lightweight torpedoes from aircraft was conceived in the early 1910s by Bradley A. Fiske, an officer in the United States Navy. A patent for this was awarded in 1912. Fiske worked out the mechanics of carrying and releasing the aerial torpedo from a bomber, and defined tactics that included a night-time approach so that the target ship would be less able to defend itself. Fiske imagined the notional torpedo bomber would descend rapidly in a sharp spiral to evade enemy guns, then at an altitude of about would level off long enough to line up with the torpedo's intended path. The aircraft would release the torpedo at a distance of from the target. In 1915, Fiske proposed attacking enemy fleets within their own harbors using this method, if there was enough water (depth and expanse) for the torpedo to run. However, the United States Congress appropriated no funds for aerial torpedo research until 1917 when the U.S. entered into direct action in World War I. The U.S. would not have special-purpose torpedo planes until 1921.
First torpedo aircraft
Meanwhile, the Royal Naval Air Service (RNAS) began actively experimenting with this possibility. The first successful aerial torpedo drop was unofficially performed by the later RFC pilot Charles Gordon Bell on 27 July 1914 - dropping a Whitehead torpedo from a Short S.64 seaplane. Gordon Bell was followed the next day by RNAS pilot Arthur Longmore, when officially testing an aerial torpedo. The success of these experiments led to the construction of the first purpose-built operational torpedo aircraft, the Short Type 184, built from 1915.
An order for ten aircraft was placed, and 936 aircraft were built by ten different British aircraft companies during the First World War. The two prototype aircraft were embarked upon HMS Ben-my-Chree, which sailed for the Aegean on 21 March 1915 to take part in the Gallipoli campaign.
Around the same time of the Royal Navy experiments, in Italy Captain Alessandro Guidoni of the Regia Marina was conducting similar trials since 1913, with the help of inventor Raúl Pateras Pescara, and in February 1914 successfully dropped an 800 lb torpedo, leading to disputes over which country first used an aerial torpedo.
First World War
In November 1914, Germans were reportedly experimenting at Lake Constance with the tactic of dropping torpedoes from a Zeppelin. In December 1914, Squadron Commander Cecil L'Estrange Malone commented following his participation in the Cuxhaven Raid that "One can well imagine what might have been done had our seaplanes, or those which were sent out to attack us, carried torpedoes or light guns."
On 12 August 1915 a Short Type 184, piloted by Flight Commander Charles Edmonds, was the first aircraft in the world to attack an enemy ship with an air-launched torpedo. Operating from in the Aegean Sea, Edmonds took off with a , torpedo to fly over land and sank a Turkish supply ship in the Sea of Marmara.
Five days later, a Turkish steamship was sunk by a torpedo aimed again by Edmonds. His formation mate, Flight Lieutenant G. B. Dacre, sank a Turkish tugboat after being forced to land on the water with engine trouble. Dacre taxied toward the tugboat, released his torpedo and was then able to take off and return to Ben-My-Chree. A limitation to using the Short more widely as a torpedo bomber was that it could only take off carrying a torpedo in conditions of perfect flying weather and calm seas, and, with that load, could only fly for a little more than 45 minutes before running out of fuel.
On May 1, 1917, a German seaplane loosed a torpedo and sank the British steamship Gena off Suffolk. A second German seaplane was downed by gunfire from the sinking Gena. German torpedo bomber squadrons were subsequently assembled at Ostend and Zeebrugge for further action in the North Sea. Later in 1917, the U.S. Navy began to perform trials using a dummy torpedo that, in the first test, porpoised from the water back into the air and almost hit the aircraft that dropped it. Several British torpedo bombers were built, including the Sopwith Cuckoo, the Short Shirl and the Blackburn Blackburd, but a squadron was assembled so late in the war that it achieved no successes.