Savoia-Marchetti S.55

The Savoia-Marchetti S.55 was a double-hulled flying boat produced in Italy beginning in 1924. Shortly after its introduction it began setting records for speed, payload, altitude and range.

Design and development
The S.55 featured many innovative design features. All the passengers or cargo were placed in the twin hulls, but the pilot and crew captained the plane from a cockpit in the thicker section of the wing between the two hulls. The S.55 had two inline counter-rotating propellers, achieved by mounting the twin engines back to back. The engines were canted sharply at an upward angle. Two wire-braced booms connected the triple-finned tail structure to the twin hulls and wing.

Operational history
Even though its design was unusual, the Savoia-Marchetti S.55 was a remarkably airworthy craft. In 1926, the S.55P prototype set 14 world records for speed, altitude and distance with a payload. The S.55's greatest successes, however, were its many flights between Europe and the Americas.

The Brazilian João Ribeiro de Barros and his crew of three made an Atlantic crossing in S.55 "Jahú" on 24 April 1927. Departing from Santiago Island, he crossed the Atlantic in "Jahú" and landed at Fernando de Noronha Island, Brazil.

The Savoia-Marchetti S.55 made a number of early crossings of the Atlantic Ocean at a time when doing so was still a very risky and challenging venture, starting when the Plus Ultra, a Spanish Dornier Wal piloted by Ramón Franco, crossed from Spain to Buenos Aires, Argentina, in January 1926, then Santa Maria under Francesco de Pinedo took off from Dakar, Senegal to Pernambuco, Brazil on 13 February 1927. This was three months before Charles Lindbergh's solo crossing, but nearly 8 years after Alcock and Brown had completed the first non-stop crossing in 1919 in a Vickers Vimy. After crossing the aircraft was traded to Brazil for coffee beans. Pilots Francesco de Pinedo and Carlo del Prete took off from Sesto Calende, Italy, in an S-55 and headed west across the South Atlantic. Four months later, they arrived back in Italy, having flown nearly 48,280 km in 193 flying hours and having made just over 50 stops, including Rio de Janeiro, Buenos Aires and New York City.

The Italian Air Marshall of the time, Italo Balbo became famous for organizing a squadron of S.55s for Atlantic crossings, culminating in his 1933 flight with 24 aircraft to Chicago's Century of Progress International Exposition. On 1 July 1933, General Balbo commanded a flight of S-55s from Orbetello, Italy, completing the flight in just over 48 hours, maintaining a tight "V" formation. These large fleets of aircraft were sometimes called a "Balbo".

The aircraft went on to serve in the Regia Aeronautica as a long-range bomber and patrol aircraft, but by World War II, the last S.55s were no longer serviceable and were in reserve.

Surviving aircraft
The last remaining example is preserved in Brazil, at the TAM "Asas de um sonho" museum, at São Carlos, São Paulo. The aircraft, registered I-BAUQ, was the S.55 used by Cmdr. João Ribeiro de Barros in his crossing of the South Atlantic in 1927.

Variants

 * S.55
 * Prototypes and original production model delivered from 1927 to 1930, 90 built, including two prototypes.


 * S.55C
 * Civil variant delivered from 1925 to 1926, eight built.


 * S.55P
 * Improved civil variant with enlarged hull for 10 passengers and enclosed cockpits delivered from 1928 to 1932, 23 built.


 * S.55A
 * Military variant delivered with 418 kW (560 hp) Fiat A.22R engines, 16 built.


 * S.55M
 * Variant with some wood structures replaced by metal, seven built by Piaggio in 1930.


 * S.55 Scafo Allargato
 * Widened and deepened hull and enclosed cockpits, 16 built by Savoia-Marchetti and 16 built by CANT.


 * S.55 Scafo Allargatissimo
 * Variant with greatly enlarged hull, 20 built by Savoia-Marchetti, 16 built by Macchi and six built by CANT.


 * S.55X
 * Variant fitted with Isotta-Fraschini Asso 750 engines for North Atlantic formation flights, later armed and used as a reconnaissance-bomber. 25 built.

Civil operators

 * Aeroflot
 * Aeroflot

Military operators

 * 🇮🇹 Italy
 * Regia Aeronautica
 * Brazilian Navy (8 airplanes)
 * 🇪🇸 Spain (1937)
 * Spanish Air Force
 * 🇷🇴 Romania
 * Royal Romanian Air Force (7 airplanes 1933-1943, all lost)
 * Royal Romanian Air Force (7 airplanes 1933-1943, all lost)

General characteristics

 * Crew: 5-6
 * Length: 16.75 m (55 ft 0 in)
 * Wingspan: 24.00 m (74 ft 9 in)
 * Height: 5.00 m (16 ft 5 in)
 * Wing area: 93.0 m² (1,001 ft²)
 * Empty: 5,750 kg (12,677 lb)
 * Loaded: kg ( lb)
 * Maximum takeoff: 8,260 kg (18,210 lb)
 * Powerplant: 2x Isotta-Fraschini Asso 750V, 656 kW (880 hp) each

Performance

 * Maximum speed: 279 km/h (173 mph)
 * Range: 3,500 km
 * Service ceiling: 5,000 m (16,405 ft)
 * Rate of climb:  m/min (  ft/min)
 * Wing loading: kg/m² ( lb/ft²)
 * Power/Mass: kW/kg ( hp/lb)

Armament

 * 4 x 7.7 mm (.303 in) machine guns
 * 1 x torpedo or
 * 2,000 kg (4,409 lb) of bombs