Directional Gyro / Turn Indicator, Type C-1 Sperry 657069, US Army Air Force OH-6 Cayuse Removing a small cover at

Removing a small cover at the rear reveals three vacuum tubes (one of the cover's metal tabs is broken)

So our assumption is that this item was offered prior to 1929

Beaufighter

receiving ground signal from a selected transmitter via its loop antenna mounted top or bottom of the fuselage

hydraulics

Directional Gyro / Turn Indicator, Type C-1 Sperry 657069, US Army Air Force OH-6 Cayuse Removing a small cover atHere is an electrical Directional Gyro Turn Indicator marked AF USARMY (Air Forces US Army), Type C 1. According to the Maintenance Interchangeability Cross Reference Charts of the Air Forces US Army, the C 1 Directional Gyro was used in versions of the Curtis P 40N Warhawk and Bell P 39N Airacobra Fighters and the A 30 Martin Baltimore light bomber. The left knob rotates the course setting indicator, a small pointer which travels the perimeter of the