A torpedo bomber is a bomber aircraft designed primarily to attack ships with torpedoes, but they could also carry out conventional bombings. Torpedo bombers existed almost exclusively prior to and during WWII, when they were an important player in many famous battles, notably the British attack at Taranto and the Japanese attack on Pearl Harbor. The introduction of improved weapons that could be carried by conventional bombers, notably anti-shipping missiles, led to the type's disappearance almost immediately after the war.
The torpedo bomber first appeared during the later years of World War I.
Generally, they carried torpedoes 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 a contemporary single-engined bomber), the aircraft carrying it needed to have a more powerful engine. Carrying torpedoes also required a long bomb-bay (or in any case a longer fuselage), which was why a special type of plane was needed for this role.
A number of multi-engined, heavier aircraft have also been used in the torpedo bomber role, with the Mitsubishi G4M "Betty" being used in the sinking of Prince of Wales and Repulse. The same squadron and planes later attempted a torpedo attack on USS Lexington but the carrier's combat air patrol and anti-aircraft guns downed 17 of the Japanese planes, which exposed the vulnerability of this type against such defenses.
Torpedo bombers disappeared almost immediately at the end of the war, replaced by more generalized aircraft, and then missiles. However, some postwar jet aircraft (such as the Ilyushin Il-28) were adapted as torpedo bombers in the late 1940s and 1950s. The North Korean Air Force notably had the world's last operational torpedo bombers in the 1980s.
In a parallel development, some maritime strike aircraft and helicopters have been capable of launching guided torpedoes against submarines. However, the mode of operation of these aircraft is considerably different.
Torpedo planes were best used as part of a coordinated attack. For instance, during the attack on the battleship Yamato, fighter planes would strafe the ship with machine guns to suppress its anti-aircraft gun fire, while dive bombers would try to cause havoc and cause topside damage, all while leaving the torpedo bombers unmolested so they could make their attack runs.
Technically, the best way to achieve a hit was 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 extremely rare. Combat air patrols and anti-aircraft fire quickly broke approaching plane formations, after which each plane was on its own and were unlikely to be able to coordinate such an attack.
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). However, 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.
Empire of Japan