Macchi M72. Schneider Trophy contestant and outright speed record holder.

Below are two most beautiful examples of Art in Engineering. Although surrounded by stunningly spectacular competitors in the early 30s Schneider races, I think this is the most dramatic of all of the aircraft. Unsuccessful at competing in the '31 Schneider Trophy due to problems that include a strange backfire at very high speed (later identified as an intake issue and with the help of  British chemist and engineer Rod Banks with fuel development, the problem was cured). The back fire eventually resulted in tragedy when it ignited the pressurised induction charge within the inlet and supercharger, causing one and possibly a second fatal accident). All was not lost however, as the aircraft continued development to capture the waterplane world speed record and, for a while, the outright world speed record. This waterplane record continued until 1961 when a Russian jet powered seaplane exceeded the nominal 442 mph figure.

Thank you to Wikimedia for the photographs

The engine of the Macchi 72 is an equally spectacular Fiat AS6. A V24 in the configuration of tandem V12s, the rear portion driving the one propeller and the front 12 cylinders driving the second of the contra rotating propellers via the central gear reduction arrangement and shafts running between the vee of the front engine.