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Gunsight Projector

Technical Information

Catalogue No: C0023
Category: Gunsight
Object Type: Indicator/Instrument
Object Name: Gunsight Projector
Part No: 8B/2519
Serial No: 2440/44
Manufacturer: Unknown
Division: Unknown
Year of Manufacture: circa 1940
Dimensions: Width (mm): 150
Height (mm): 140
Depth (mm): 240
Weight (g): 0
Location: Displays' Meet & Demo Room

Stores Ref No. 8B/2519
Projector Type I Mark I
A.M. Serial No. 2440/44
British Patent No. 504845/1937
British Patent No. 846742/1938
U.S. Patent No. 2190569/1938


The GM 2 reflector sight was fitted to aircraft such as the Hurricane and Spitfire and saw widespread use throughout the war with eventually over 84,000 units being delivered (65,000 between 1937 and 1942 from Barr & Stroud's factory at Anniesland in Glasgow alone).

The Reflector Sight provided the pilot with the means to fix on a target and measure its range, when the line of sight was the same as the pointing direction of the guns.

A substantial rubber "bumper" would have been fitted to the front to protect the pilot from injury in a rough landing. The upper ring can be turned to preset a range and the lower ring sets wingspan and an internal mechanism accordingly adjusted the projected graticule. The graticule was a ring bisected by a cross broken in the centre and this was the gap set by these two controls.. The graticule was illuminated by a 12v lamp in a quick release holder at the base of the Sight body.

The Type I Mk I was a special version optimised for firing rockets and 40mm guns and it did not have the reflector glass but projected off the windshield. It should also have only one control ring which moved the graticule forwards or backwards, raising it or lowering it on the windshield. It does have the depression control on the right hand side which tilted the reflector glass through 0° to 5° being set by the pilot to match airspeed and the known drop of the missiles being fired. So this model is somewhat of a mystery having the Type I Mk I designation but retaining the reflector glass with two control rings. It is actually a Type I MkII conversion which was known as the MkIIL.

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