Designed by Max Friz and based on the Rapp III engine, it was an SOHC in-line six-cylinder, just as the earlier Mercedes D.III was, which guaranteed optimum balance, therefore few, small vibrations.

As early as 1915, the IdFlieg German military aviation inspectorate introduced uniform model designations for aero engines, with the Roman numeral referring to the performance class.

Burning a special high octane fuel of gasoline blended with benzole, the carburettor adjusted the richness of the fuel-air mixture according to the aircraft's altitude.

This discrepancy may explain the significant difference in performance of the BMW IIIa equipped Fokker D.VIIF both against Mercedes powered D.VII's and their Allied opponents.

When equipped with the BMW IIIa engine, the Fokker D VII could outclimb any Allied opponent it encountered in combat.

The water-cooled in-line 6-cylinder engine's reputation grew very quickly after its abilities were proven in air combat by Jasta 11, the "Red Baron's" squadron.