Bombardiers' Information File US Army Air Force May 1945 Piasecki This is a centrifugal tachometer:

This is a centrifugal tachometer: as the rotation of the engine shaft rotates a cable attached to the case

"Kelly" Johnson

The "retiflector" sight is mounted in the center below the elevation gyroscope and above the azimuth gyroscope

but utilizes an electro-magnetic compensation system

The Army Type F-2 Airspeed Indicator was used across a number of US Army Air Corps and Air Force aircraft during WWII

Bombardiers' Information File US Army Air Force May 1945 Piasecki This is a centrifugal tachometer:Here is a WWII era Bombardiers' Information File published by the US Army Air Force May 1945. It contains the essential information on the duties and responsibilities of the bombardier. It is in exceptional condition given its age. Measures 8. 5 x 11 inches, and ~0. 5 inches thick.