Plotting Board Mark 7 MIL-B-5046B MiG-21 the angle can be obtained

the angle can be obtained

Here is a WWII-era Pilots' Information File published by the US Army Air Force with revisions through April 1945

used for the Twin Compass System

as well as for radar sets AN/APS-3 and - 4

made by Lear PN 62160-01 MIL-I-6501A

Plotting Board Mark 7 MIL-B-5046B MiG-21 the angle can be obtainedThis is an authentic US Navy pilot's Chart Plotting Knee Board Mark 7 (MIL B 5046B), likely 1950's to Vietnam War era. Likely designed for a jet aircraft (note fuel is measured in lbs), this 9. 5 x 7 x 1 inch device included the flight computer on the face with a rotating card for determining the critical factors impacting the planned flight. By depressing a button in the lower right corner, the top flips open to reveal a map compartment, clips for