Synchroscope Kollsman 549N-06 PBY Catalina 2 DC-7 this pre-WWII instructional manual is

this pre-WWII instructional manual is for the Aircraft Instruments course of The Department of Mechanics in The Air Corps Technical School

but not bad given the age of the instrument

or Elevator/Nose Position Indicator

an amplifier and the indicator

The right hand knob turned the system on and off

Synchroscope Kollsman 549N-06 PBY Catalina 2 DC-7 this pre-WWII instructional manual isThis is an authentic WW2 vintage Dual Engine Synchroscope Indicator made by Kollsman, PN 549N 06, as used in the WW2 era US Navy's Consolidated PBY Catalina Patrol Bomber Seaplane (see photo of PBY Instrument Panel from the Pilots Flight Manual with a yellow dot showing instrument location). The US Navy Anchor logo is stamped on the back and on the face is embossed "BU AERO US NAVY" (Bureau of Aeronautics). A synchroscope informed the pilot or flight