Directional Gyro / Turn Indicator, Type C-1 Sperry 657069, US Army Air Force OH-6 Cayuse In the servoed mode

In the servoed mode

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

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

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

Tachometers

Directional Gyro / Turn Indicator, Type C-1 Sperry 657069, US Army Air Force OH-6 Cayuse In the servoed modeHere 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