Course Setting Bomb Sight

The CSBS Mk. IX mounted in a Fairey Battle. The bomb aimer is sighting through the white ring-shaped backsights to the pin shaped foresights (just visible against the armoured cable) and holding the bomb release switch in his right hand.

The Course Setting Bomb Sight (CSBS) is the canonical vector bombsight, the first practical system for properly accounting for the effects of wind when dropping bombs. It is also widely referred to as the Wimperis sight after its inventor, Harry Wimperis.

The CSBS was developed for the Royal Naval Air Service (RNAS) in order to attack submarines and ships. It was introduced in 1917, and was such a great advance over earlier designs that it was quickly adopted by the Royal Flying Corps, and the Independent Air Force. It has been called "the most important bomb sight of the war".[1][2]

After the war the design found widespread use around the world. A US version of the CSBS was used by Billy Mitchell on his famous attack on the Ostfriesland in 1921.[3] The basic design was adapted by almost all air forces and used well into World War II. It was eventually replaced in British service by more advanced designs like the Mark XIV bomb sight and the Stabilized Automatic Bomb Sight. Other services used vector bombsights throughout the war.

  1. ^ Goulter 1995, p. 27.
  2. ^ Abbatiello 2006, p. 32.
  3. ^ Zimmerman, David (2010). Britain's Shield: Radar and the defeat of the Luftwaffe. Amberley Publishing. p. 69.