Tachometer, Helicopter, USSR 0-4000 RPM C-7 Here is an original WWII-era

Here is an original WWII-era (1943) Service Guide for aviation equipment made by the Bendix Aviation Corporation under its brands Eclipse

The Suction Gage measured the amount of vacuum generated to power the pneumatically-operated gyroscopic instruments

The star chart for the intended course of the aircraft was selected from among the 7 canisters stored in the wooden case

For example

and lettering are in exceptional condition

Tachometer, Helicopter, USSR 0-4000 RPM C-7 Here is an original WWII-eraHere is a Cold War era electronic dual Tachometer, 0 4000 RPM, as used in military helicopters of the USSR and Poland such as the MIL MI 1 (see cockpit photo, the tachometer is in the middle of the second column of instruments from the right) and MIL MI 4 (see cockpit photo, the tach is in the bottom row 3rd instrument from left). The pointer labeled "P" indicates RPMs of the Rotor, while the pointer labeled "M" indicates RPMs of the Engine. It is in