VINTAGE 

Soviet Air Force Military aircraft navigation slide rule .

The navigational slide rule NRK-2 is a calculating tool for pilots and navigators and is intended for fulfilling the necessary calculations in the preparation of the flight and in-flight calculations .

Diameter approx : 15.5 cm ( 6.1 inch )

Weight  : 112 gram 
Navigation calculator NRK-2.
 It is a counting tool,
designed to perform navigation calculations in preparation for flight and in flight.
With the help of the navigational calculator the following tasks are solved:
a) calculating the drift angle, ground speed, heading angle of the wind,
       the flight path or the actual track angle along the known wind vector;
b) determination of the wind from a known angle of drift and track speed,
       at two angles of drift and at two track speeds;
c) determining the distance traveled, the speed and time of flight;
d) determination of the radius and return time by a given angle from the known velocity and angle of heel;
e) recalculation of the true speed in the instrument and instrumental in the true in the range of 100-2500 km / h;
e) determination of the number M corresponding to a given flight speed and vice versa;
g) determination of the correction for the compressibility of air in the readings of the wide arrow of aerodynamic
      speed indicators;
h) recalculation of the true height in the instrument and instrumental in the true in the range of 100-25000m;
i) determination of the value of trigonometric functions,
      multiplication and division of numbers by trigonometric functions of angles.

Besides ,
 The navigation calculator allows you to perform some other mathematical calculations,
 as well as the transfer of sea and English miles per kilometer,
 feet in meters,
 millimeters of mercury to millibars,
 degrees in radians and vice versa.
The navigation calculator M.V .Kalashnikova. 
The most common modification of NRK-2 .
-  Analog NL-10M.
100% ORIGINAL .
 Please if you see a mistake in the listing description do not buy or bid the item but write me via email for it . 
 Thank you in advance

Vintage USSR 

original 100 % 
Grab yourself a bit of history .

Best wishes .
GOOD LUCK !

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