Gyro Horizon OV-1 These posters have been linked

These posters have been linked to a US Navy procurement order of "GPO Order 11174

It is in terrific condition given its age

As an offshoot of this equipment Ryan have also developed a helicopter hovering aid (AN/APN-97) which presumably uses Doppler signals to tell the pilot whether or not his machine is stationary above ground or sea

it is in fine condition given its apparent age

one for each engine

Gyro Horizon OV-1 These posters have been linkedThis is a pre WWII era Gyro Horizon (Flight) Indicator, Army Type C 5, made by Sperry, part number 643770, marked for the Air Corps US Army. This indicator has a serial number prefix "AC 40", evidence of a manufacturing year 1940, prior to the US entering WWII. The C 5 Gyro Horizon was used across all aircraft of the US Army Air Corps, including bombers B 17, B 24, B 25, fighters P 38, P 40, P 47, P 51, and transport C 47. The Gyro Horizon provided