Whitehead Torpedo Mark IX

Robert Whitehead, a British engineer, developed the modern torpedo. In 1864, the Austrian Navy sought out Whitehead to create an explosive-carrying, self-propelled boat that could be steered from its launch site by yoke lines. After Whitehead built a model of this device, he rejected it as impractical and began working on a design of his own. By 1866 he had built a successful torpedo.

The main body of the torpedo is a compressed air flask, with the explosive warhead in the tip and the engine and steering mechanisms in the tail. The first Whiteheads were much smaller, 8 inches in diameter and between 11 and 14 feet long, while the 21” torpedo would not be perfected for decades. The first torpedoes were controlled by a hydrostatic valve that operated rudders on its horizontal tail surfaces, but there was no provision for lateral steering. By 1895, the gyroscope came into use for directional control, correcting any deviation from its set course. 

The Mark IX was first used in 1930, and the IX* modifications allowed for more explosive charge and larger range. These torpedoes were mostly used on cruisers and later by destroyers.

Mark IX* used a burner-cycle engine, a system similar to diesel engines that used high-temperatures and highly pressurised air with injected kerosene-type fuel to power the torpedo forward.

Reference Links:
Canadian War Museum - Torpedo
Britannica - Torpedo