• WWII USAAF D-4 Flight Computer. 1944


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    This a Model D-4 flight computer as used by USAAF Bomber crews during WWII. This particular example was made by G Felsenthal & sons with a 1944 contract date.

    It is used by aviators to calculate air speed, pressure altitude, ETA, ground speed, etc. It is a circular slide-rule with dual concentric wheels mounted to the front and rear of a stationary scale. The material is sturdy plastic and held together with a rivet and washers. All print appears as yellow on black background. The wheels turn easily and still have enough friction to hold where they are set. Please see photos for other descriptive details