page_title: Mark XIV bomb sight
section_title: Production and use
hierarchical_section_title: Mark XIV bomb sight / History / Production and use
caption_attribution_description: English: The T-1A computer, the US version of the Mk. XIVA "computor". This differs from the Mk. XIV only in minor details, most notably that the dials are not coloured, and this example retains all of the scales in front of the various reading windows. This example also has a levelling card, blank, held in the clips in the upper right.
context_page_description: The Mark XIV Bomb Sight was a bombsight developed by Royal Air Force Bomber Command during the Second World War. It was also known as the Blackett sight after its primary inventor, P. M. S. Blackett. Production of a slightly modified version was also undertaken in the United States as the Sperry T-1, which was interchangeable with the UK-built version. It was the RAF's standard bombsight for the second half of the war.
  Developed starting in 1939, the Mk. XIV began replacing the First World War–era Course Setting Bomb Sight in 1942. The Mk. XIV was essentially an automated version of the Course Setting sight, using a mechanical computer to update the sights in real-time as conditions changed. The Mk. XIV required only 10 seconds of straight flight before the drop and automatically accounted for shallow climbs and dives. More importantly, the Mk. XIV sighting unit was much smaller than the Course Setting sight, which allowed it to contain a gyro stabilization platform. This kept the sight pointed at the target even as the bomber manoeuvred, dramatically increasing its accuracy and ease of sighting.
  The Mk. XIV was theoretically less accurate than the contemporary Norden bombsight.
context_section_description: Existing sources do not record when the Mk. XIV went into production in the UK; operational testing started in January 1942, and production examples started reaching squadrons in March. It was manufactured by small machine shops and instrument makers like the Aron Meter Company. Production was too slow to meet the demand; between July and October, fewer than a hundred a month were being delivered. As the design was finalized, automated production was undertaken and by mid-1943, 900 a month were available. This was enough to equip the heavy bombers as they arrived from the production lines and by late 1942 the Handley Page Halifax was being delivered with the sight head already installed.
  To fill the demand for other aircraft, especially smaller ones like the de Havilland Mosquito, the Air Ministry began looking at US manufacturers to supply the bombsight. Frederic Blin Vose of Sperry Gyroscope expressed an interest in the design and felt he could adapt the Mk. XIV to US production methods and have it in mass production rapidly. Sperry arranged for AC Spark Plug to take over manufacture, initially on a sub-contract basis and later for direct sales to the UK.
  The two companies made some basic changes to the design to make it easier to produce and a final design was ready in May 1942. The Sperry T-1 was fully compatible with UK-built versions and a T-1 computer could be used with a Mk. XIV sight head or vice versa. Full production commenced at the AC plant in Flint, Michigan, in November and T-1s arrived in the UK from March 1943. The sights were sent to medium bombers like the Wellington, while UK-built versions were sent to the heavy bombers. In August 1943, George Mann of AC Spark Plug visited the UK for a period of about a year, liaising with RAE Farnborough, Boscombe Down and the Ministry of Aircraft Production.
caption: The T-1A computer, a US-built version of the Mk. XIVA computor. This example retains the scales in the reading windows and a blank levelling card.
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