Altimeter, Sensitive, Type C-12, 50,000 ft, US Army Air Force WWII JU-88 As an offshoot of this

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

The clock is wound by turning this red knob counterclockwise from its home position

The system included a sighting head connected to a mechanical (pneumatic) computer

as used in the US Army Air Force's Boeing B-29 Superfortress (see photo of B-29 Flight Engineer's instrument panel with a red dot showing instrument location)

Altimeter, Sensitive, Type C-12, 50,000 ft, US Army Air Force WWII JU-88 As an offshoot of thisHere is an early WWII era Sensitive Altimeter, Air Corps US Army Type C 12, made by Conn. The C 12 Altimeter was used across all aircraft of the Air Corps US Army, including heavy bombers B 17 and B 24, medium bombers, B 25 and B 26, Fighters P 38, P 39, P 40, P 47, and P 51, and transports C 46 and C 47, according to the Maintenance Interchangeability Chart dated Dec 1943. It has a serial number prefix AF 43, evidence of a manufacturing year 1943.