Macchi M.39

Aeronautica Macchi

Industry	Aerospace
Headquarters	Varese , Italy

The Macchi M.39 was a high-speed seaplane engineered for competitive racing by the Italian manufacturer Aeronautica Macchi. This aircraft is chiefly noted for setting several world speed records in the mid-1920s and securing victory in the Schneider Trophy, for which it had been purpose-built.

Conceived by Mario Castoldi and assembled in Varese, located in northwestern Lombardy, the M.39 marked a significant evolution from Macchi's earlier racing flying boat, the Macchi M.33. It featured a streamlined fuselage, an open cockpit designed for a single pilot, and a monoplane wing supported by bracing. The aircraft’s twin floats replaced the traditional central hull design, which was known to hinder aerodynamic efficiency. Notably, approximately two-thirds of the upper wing surfaces served as surface radiators, providing effective engine cooling with minimal aerodynamic drag. Propulsion was delivered by a Fiat AS.2 V-12 piston engine distinguished by an unusually high power-to-weight ratio for its time.

Two configurations of the M.39 were created: a trainer model and a racing variant. The initial flight of the M.39 occurred on 6 July 1926 with the trainer aircraft MM.72. During the Schneider Trophy competition held on 13 November 1926 at Hampton Roads, Virginia, three M.39s competed; piloted by Mario de Bernardi, MM.76 won first place, achieving an average velocity of 396.698 kilometres per hour (246.497 mph) and establishing a new seaplane speed record, while MM.74, flown by Adriano Bacula, secured third position.

Design and development

The Italian aeronautical engineer Mario Castoldi designed the M.39 specifically to represent Italy in the 1926 Schneider Trophy race. This model represented a major shift from his earlier work, as it was Macchi's first low-wing monoplane design, diverging substantially from the central-hull layout of the preceding Macchi M.33. The earlier hull-based design, although providing excellent water stability, was identified as a significant impediment to aerodynamic efficiency and thus was replaced with a pair of braced floats that offered rigid support during water operations. Manufacturing took place at Macchi’s facility in Varese, situated in northwestern Lombardy.

Constructed using both metal and wood materials, the aircraft was a single-seat twin-float seaplane. The pilot occupied an open cockpit positioned just aft of the wing’s trailing edge; its windscreen was smoothly integrated into the fuselage to minimize aerodynamic drag. The fuselage itself was deliberately shaped with smooth contours avoiding sharp angles to enhance streamlining. The tail assembly featured a large horizontal stabilizer paired with an unbalanced two-piece elevator, while the vertical stabilizers included two fins—one mounted above and another below the fuselage—alongside an unbalanced rudder without external bracing.

The wooden monoplane wing was mounted beneath the fuselage and secured with steel cable bracing. A distinctive aspect of this wing was that roughly two-thirds of its upper surface acted as low-drag surface radiators, an innovative cooling solution that eliminated the need for conventional honeycomb or fin-type radiators which would have increased drag substantially. Additionally, an oil radiator was installed on the underside of the fuselage in an exposed location to optimize cooling efficiency.

File:Macchi M.39 testing.jpg

An M.39 undergoing engine tests, c. 1926

Propulsion came from a nose-mounted Fiat AS.2 water-cooled V-12 piston engine directly driving the propeller. This powerplant featured three double carburetors—one servicing every four cylinders—engineered to function effectively regardless of aircraft orientation during flight maneuvers. Including all auxiliary components such as water jackets, oil reserves, starter mechanisms, and fuel pumps, this engine achieved an exceptionally low weight-to-power ratio of approximately 467 grams (1.03 lb) per horsepower; at that time, it was reportedly lighter than any other engine of comparable output produced worldwide.

Tailored expressly for Schneider Trophy competition demands, the M.39 incorporated specialized features to optimize performance on the racecourse, which involved predominantly left-hand turns. To facilitate tighter left turns, its left wing had a slightly longer span than its right counterpart. Moreover, float buoyancy was asymmetrical to counteract propeller torque effects during flight maneuvers. Fuel storage was also integrated within these floats.

Macchi developed two distinct variants of the M.39: a trainer and a racer model. The trainer version had an extended wingspan measuring 10.23 metres (33 ft 7 in), compared to 9.26 metres (30 ft 4½ in) on racing versions, and was powered by a 447-kilowatt (600-horsepower) Fiat AS.2 liquid-cooled V12 engine; meanwhile, racing models were equipped with more powerful versions delivering 597 kilowatts (800 horsepower). In total, Macchi constructed two trainers, three racers, plus one static test airframe for structural evaluations. The first completed aircraft was the trainer MM.72, assembled within only a few months and followed shortly thereafter by MM.73 (the second trainer), MM.74 through MM.76 (the racers), and finally the non-flying static test unit.

Operational history

File:Macchi M.39 right 2009-06-06.jpg

File:Macchi M.39 front 2009-06-06.jpg

The Macchi M.39 preserved in Italy at the Museo storico dell'Aeronautica Militare di Vigna di Valle, captured in a photograph dated 6 June 2009. This particular aircraft, MM.76, was piloted by Major Mario de Bernardi during his victory in the 1926 Schneider Trophy race and set two global speed records that same year.

The initial flight of the trainer MM.72 took place on 6 July 1926, marking the first time an M.39 took to the skies. Unfortunately, on 16 September 1926, the Italian Schneider team leader lost control of one trainer aircraft over Lake Varese, resulting in a fatal crash into the water. Despite this tragedy, development efforts for the M.39 continued without interruption.

On 13 November 1926, all three M.39 racers competed in the Schneider Trophy event held at Hampton Roads, Virginia, USA. During the race, MM.75 encountered a ruptured pipe and was forced to withdraw prematurely. However, MM.76, under the command of Mario de Bernardi, secured first place with an average velocity of 396.698 kilometres per hour (246.497 mph), establishing a new world speed record for seaplanes. Meanwhile, MM.74, flown by Adriano Bacula, achieved third place.

Just four days later, on 17 November 1926, de Bernardi piloted MM.76 to set another world speed record of 416.618 kilometres per hour (258.874 mph) over a 3 kilometres (1.9 mi) course at Hampton Roads.

The design principles of the M.39 were carried forward by Castoldi in developing his subsequent racing seaplane model, the Macchi M.52.

Surviving aircraft

The MM76 machine, famously flown by de Bernardi to win the Schneider Trophy and establish a new global speed record, is currently exhibited at the Museo Storico Aeronautica Militare located in Bracciano.

Operators

Template:Country data Kingdom of Italy

• Regia Aeronautica

Specifications (M.39 racer)

File:Macchi M39.svg

Macchi M.39

See also

Bibliography

• Angelucci, Enzo. World Encyclopedia of Civil Aircraft. London: Willow Books, 1984. ISBN 0-00-218148-7.
• Donald, David, editor. The Complete Encyclopedia of World Aircraft. New York: Barnes & Noble Books, 1997. ISBN 0-7607-0592-5.
• Eves, Edward. The Schneider Trophy Story. Shrewsbury: Airlife Publishing Ltd., 2001. ISBN 1-84037-257-5.
• James, Derek. Schneider Trophy Aircraft. London: Putnam, 1981. ISBN 0370303288
• Lefèbvre, Jean-Michel and Foxworthy, Thomas. "Vitesse à la italienne: Macchi M.39, partie 1." Le Fana de l'Aviation, May 1978, no. 102, pp. 8–11. ISSN 0757-4169 (in French).
• Lefèbvre, Jean-Michel and Foxworthy, Thomas. "Vitesse à la italienne: Macchi M.39, partie 2." Le Fana de l'Aviation, June 1978, no. 103, pp. 8–11. ISSN 0757-4169 (in French).
• "Macchi M. 39 Seaplane: Single-Seat Racer with an 800 HP Fiat 'A-S2' Engine." National Advisory Committee for Aeronautics, March 1, 1927. NACA-AC-32, 93R18823.

External links

• Newsreel showing Macchi M.39 MM.76 and Major Mario de Bernardi following the victory in the 1926 Schneider Trophy race Archived 11 June 2011 at the Wayback Machine