Suction Gage, US Navy Oscar Fighter Since the factory seals are

Since the factory seals are intact over screw heads

This is a complete unbound collection of The Aeroplane Spotter

The caption on the photo states that this German POA mortar emplacement on the eastern front consists exclusively of Russian Volunteers

made by Waltham to Air Corps US Army spec #94-27749

This is a WWII-era pneumatic Valve

Suction Gage, US Navy Oscar Fighter Since the factory seals areThis is a US Navy Suction Gage, made by Kollsman. It is labeled as last service at Naval Air Station Quonset Point, RI, in 1953. The Suction Gage measured the amount of vacuum generated to power the pneumatically operated gyroscopic instruments, such as the Gyro Horizon (Flight Indicator), the Directional Gyro, and the Turn and Bank Indicator, as well as automatic pilot systems. The vacuum is generated by either a engine powered vacuum pump or