Macchi M.33
A single-seat racing flying boat designed by Mario Castoldi and built by Aeronautica Macchi for Italy's 1925 Schneider Trophy challenge at Baltimore. Its cantilever monoplane layout was advanced for a flying boat, but its engines were worn second-hand Curtiss D-12s; Giovanni de Briganti finished third, and his M.33 was the last flying boat to compete for the Schneider Trophy.
Why It Mattered
The Macchi M.33 was built to carry Italy's challenge for the 1925 Schneider Trophy, the international seaplane racing contest of the 1920s. It was the first racer Mario Castoldi designed for Macchi, and its sleek cantilever monoplane layout broke with the biplane flying boats the company had raced before. The effort ran on a shoestring: the Italian government supplied only the two American engines, and Macchi itself bore the cost of the team's appearance at Baltimore. De Briganti's third place there closed a chapter in the contest's history, for his was the last flying boat ever to compete for the Schneider Trophy.
Design Notes
Castoldi built the M.33 around a slim wooden hull with a very flat planing bottom and a single step set well forward, the long rear section running back to a swept-up fin and rudder. The thick two-spar wooden wing was made in three sections, its centre section integral with the hull, and carried small teardrop stabilizing floats strut-mounted beneath it. The pilot sat in an open cockpit above the wing, behind a streamlined headrest. The engine stood high above the hull on N-struts, enclosed in a streamlined nacelle and driving a two-bladed propeller. Cooling was the design's dated feature: plate radiators sat at the back of the nacelle, when newer racers were already turning to surface radiators. Power came from a used 1923 Curtiss D-12 rated at 507 horsepower, an engine Italy resorted to because it had no competitive racing engine of its own.
Operational History
Three M.33s were built at Varese: two flying examples, MM48 and MM49, and a third airframe used for structural testing. Flight testing took place on Lake Maggiore, where Macchi's test pilots Riccardo Morselli and Giovanni de Briganti reached nearly 199 mph, though they distrusted the cantilever wing and found the tired engines misfiring and in need of careful handling. The 1925 Schneider Trophy was raced on 26 October over Chesapeake Bay, south of Baltimore, with Italy's two M.33s facing British and American entries. Engine trouble plagued the Italians in practice; the engineers got both aircraft serviceable for the contest, but a faulty ignition system stopped Morselli starting MM48's engine, and that aircraft was withdrawn. De Briganti raced the remaining entry cautiously, holding back from full throttle for fear of his engine and wing, and lost more time with a navigational error on the second of seven laps. He finished third at an average of 271 km/h (168 mph), behind Hubert Broad's Gloster IIIA in second and Jimmy Doolittle's Curtiss R3C-2, which won at 374 km/h.
Afterlife
Both aircraft ended their careers as trainers with the Reparto Alta Velocità, Italy's high-speed flight at Desenzano del Garda. For the 1926 contest, Castoldi and Macchi produced a new monoplane racer, the M.39, and Italy won that year at Hampton Roads, Mario de Bernardi averaging 396.70 km/h. The type's widest modern audience came through fiction: the seaplane flown by the hero of Hayao Miyazaki's animated film Porco Rosso, named a Savoia S.21 in the film, was drawn to look much more like the M.33.