BMW VII A 7.3
The BMW VIIa was a water-cooled twelve-cylinder engine derived from the successful BMW VI.
Unlike the BMW VI unit, it had the magnetos arranged in front of the cylinder banks in order to simplify maintenance. The BMW was employed for the first forced-aspiration experiments with a "mixture blower" (a radial fan located behind the carburettor); this led in due course to the development of the BMW IX aircraft engine. Only a few examples of the BMW VII went into operation, in the single-engined version of the Junkers Ju 52, for example, and in the Dornier Wal which Wolfgang von Gronau flew around the world in 1932.