Drift Sight, Tail, RAF Mk IV Kit Ref No 6B/110, 1939 Viscount This instrument seems to have

This instrument seems to have had a very interesting history

75 inches diameter

intersecting them along the specified firing range

These were often carried aboard aircraft as emergency back-ups in these latter decades in the event of failure of the more sophisticated navigation computers that emerged in the 1960's and 70's

This was a personal compilation of a student or an instructor at the Amarillo Texas B-29 service school

Drift Sight, Tail, RAF Mk IV Kit Ref No 6B/110, 1939 Viscount This instrument seems to haveHere is a WWII era Tail Drift Sight, Mark IV Kit, as used in bomber and transport aircraft of the British Royal Air Force with navigator aircrew, such as the Avro Lancaster, and likely used in other bombers such as the Vickers Wellington and Short Stirling. This kit includes the optical periscope, a base plate, and the aluminum drift plate that screws onto the base plate, and wooden carry case with leather strap. Stamped on the label on the case of