B-36 Peacemaker Bomber Power Plant Computer 1951

This is an authentic Power Plant Computer designed for use in the USAF Convair B-36D Peacemaker Strategic Bomber and its reconnaissance versions RB-36D & E.  The Power Plant Computer was likely used by the flight engineer to determine parameters for the aircraft's six Pratt & Whitney R4360-41 piston engines and four General Electric J47-19 jet engines. 

This 8-inch diameter plastic computer is essentially a 3-disk slide rule. The side marked "Face A" is used to determine fuel flow rates.  "Face B" is used to determine density altitude, true air speed, and fan horsepower.  

It is in very good condition given its age.  You'll look long and hard to find another one of these, other than at the Smithsonian.