Author Topic: REL Type GI Prismatic Gunsight 1941  (Read 26 times)

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Frank Lagorio

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REL Type GI Prismatic Gunsight 1941
« on: April 16, 2019, 08:42:54 PM »
Last Sunday at a gun and militaria show I found an unusual REL optic for $20. Nobody including myself knew what it was, but after getting home I had a look at an REL YE 1945 report where they listed all optics made during the war and discovered it to be a "Gunsight, Prismatic, Type GI" of which REL made 350. Interestingly ten GI gunsights were the first optical instruments made and shipped by REL in August 1941 two months after their first production on optical glass in June 1941.  The majority of the GI prismatic sights were made by British makers including Ross as an alternative to reflector sights. They were developed in the later 1930's and used early in the war but weren't very successful and soon discontinued. However, when the Gyro Gunsight Mk I  was developed the GI prismatic sights were resurrected to be installed in them.  Because of graticule type as well as relatively late year of manufacture (1941) I believe this REL sight to be one of the ones installed on gyro sights. You'll note that the graticule has two rings, a thin inner ring and a thick outer ring. If I'm correct the outer ring is a conventional graticule and is fixed always pointing in the direction of the airplane's guns whereas the inner ring moves because it is attached to a gyroscopically controlled wand. Targeting is achieved by placing the target in the inner ring and then centering the inner ring inside the outer one. The history of the GI sight and its use in the gyroscopic gunsight is nicely explained  in this article about WW II airplane gunsights.
« Last Edit: April 16, 2019, 09:06:16 PM by Frank Lagorio »

Niall McLaren

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Re: REL Type GI Prismatic Gunsight 1941
« Reply #1 on: April 16, 2019, 11:46:26 PM »
A great find Frank - I envy you! ;)
"A little bit of something beats a whole lot of nothing." - Little Richard