Macchi M.C.72
A single-seat racing floatplane designed by Mario Castoldi and built by Aeronautica Macchi for Italy's Schneider Trophy effort. Its Fiat AS.6 engine, two V-12s driving counter-rotating propellers, carried Francesco Agello to 709 km/h over Lake Garda in October 1934, a speed no piston-engined seaplane has matched since.
Why It Mattered
The Macchi M.C.72 was built for a single contest: the Schneider Trophy, the seaplane race that set the pace of aviation speed in the 1920s and 1930s. Engine trouble kept it out of the 1931 race, and the programme continued instead as an attempt on the world speed record. In October 1934 Francesco Agello averaged 709 km/h over Lake Garda, at the time the highest speed reached by any aircraft. That mark stood as the absolute record for five years, and it remains the fastest speed ever recorded by a piston-engined seaplane.
Design Notes
Mario Castoldi designed the M.C.72 for Aeronautica Macchi as a single-seat, low-wing monoplane floatplane built of wood and metal. Its Fiat AS.6 engine joined two V-12 engines back-to-back into a single 24-cylinder unit producing 3,100 horsepower. The paired engines drove two counter-rotating propellers on one axis, so that each cancelled the other's torque. Cooling was spread across the airframe rather than gathered in a drag-producing radiator: surface radiators lay on top of the wings, with oil coolers on the floats. The engine was the design's weak point at first, backfiring and exploding in flight until its intake and carburation were reworked.
Operational History
Five M.C.72s were built for the Regia Aeronautica, whose high-speed unit at Desenzano, on Lake Garda, prepared them for the 1931 Schneider Trophy and for record attempts. Testing cost two pilots their lives: Captain Giovanni Monti and Lieutenant Stanislao Bellini were killed in separate accidents when their engines exploded. Italy withdrew from the 1931 race, which Britain won unopposed. Work on the engine continued, and by early 1933 the type was ready for record attempts. On 10 April 1933, Francesco Agello flew the first aircraft to an FAI world record of 682 km/h. On 23 October 1934, in the fifth aircraft, he raised the record to an average of 709.2 km/h over the measured course. The type never flew again after that flight.
Afterlife
The record-breaking aircraft is the type's only survivor. It is kept by the Museo Storico dell'Aeronautica Militare, the Italian Air Force museum at Vigna di Valle on Lake Bracciano, near Rome, where the Air Force presents it as the holder of the seaplane speed record at over 709 km/h. In September 2023 the aircraft was named an International Historic Mechanical Engineering Landmark by the American Society of Mechanical Engineers, in recognition of Castoldi's design and its engine. The record itself has never been seriously challenged: no piston-engined seaplane has come close to the 1934 mark.