in this photograph of a Macchi-Castoldi M.C. 72 during an engine test, the surface-mounted oil coolers on the pontoons are visible.
The M.C. 72 was powered by a liquid-cooled, supercharged, 50.256 liter (3,066.805 cubic inch), Fiat S.p.A. AS.6 24-cylinder dual overhead cam 60° V-24 engine with 4 valves per cylinder and a compression ratio of 7:1. The engine produced 3,100 horsepower at 3,300 r.p.m. with 11.5 pounds of boost (0.79 Bar), and drove two counter-rotating two-bladed fixed pitch propellers with a diameter of 2.59 meters (8 feet, 6 inches) through a 0.60:1 gear reduction. Each counter-rotating blade cancelled the torque effect of the other. Surface radiators were placed on top of each wing and surface oil coolers on the floats. The Fiat AS.6 was 3.365 meters (132.48 inches) long, 0.702 meters (27.638 inches) wide, and 0.976 meters (27.64 inches) high. It weighed 930 kilograms (2,050 pounds).
he Macchi-Castoldi M.C.72 was designed by Ing. Mario Castoldi for
Aeronautica Macchi-S.p.A. It was a single-place, single-engine, low-wing monoplane float plane constructed of wood and metal. It was 8.32 meters (27 feet, 3½ inches) long with a wingspan of 9.48 meters (31 feet, 1¼ inches) and height of 3.30 meters (10 feet, 10 inches).
The M.C.72 had an empty weight of 2,505 kilograms (5,523 pounds), loaded weight of 2,907 kilograms (6,409 pounds) and maximum takeoff weight of 3,031 kilograms (6,682 pounds).