Aeroplane Monthly 1983-04
This photograph, dated July 6, 1916, illustrates the rectangular form of the early gunsight used by the RFC. Here the backsight has only two vertical wires; a central wire may have been removed. Whatever foresight was used is unknown; it may have been lost in the dark rear surface of the airscrew. The aircraft is a Bristol Scout.
Early gunsights on a Martinsyde Elephant, 1916. The rectangular backsight is at left, partly obscured by the rear centre-section strut.