The SIAI S.58 or Savoia-Marchetti S.M.58 was an Italian

flying boat A flying boat is a type of fixed-winged seaplane with a hull, allowing it to land on water. It differs from a floatplane in that a flying boat's fuselage is purpose-designed for floatation and contains a hull, while floatplanes rely on fusela ...

fighter

prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototyp ...

of the 1920s designed and manufactured by SIAI.

Design and development

S.58

In 1924, the '' Regia Marina'' (Italian Royal Navy) issued a requirement for a replacement for its Macchi M.7''ter'' flying boat fighter. To compete with the

Macchi M.26 The Macchi M.26 was an Italian flying boat fighter prototype of 1924 designed and manufactured by Macchi. Design and development In 1924, the ''Regia Marina'' (Italian Royal Navy) issued a requirement for a replacement for its Macchi M.7''ter' ...

for a production order as the replacement, SIAI developed the S.58. It was a wooden, single-seat, single-bay

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...

with a

hull Hull may refer to: Structures * Chassis, of an armored fighting vehicle * Fuselage, of an aircraft * Hull (botany), the outer covering of seeds * Hull (watercraft), the body or frame of a ship * Submarine hull Mathematics * Affine hull, in affi ...

based on that of the SIAI S.51 racing flying boat which had participated in the 1922 Schneider Trophy race. The S.58s engine, a 221-

kilowatt The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Wa ...

(296- brake horsepower)

Hispano-Suiza Hispano-Suiza () is a Spanish automotive–engineering company. It was founded in 1904 by Marc Birkigt and Damian Mateu as an automobile manufacturer and eventually had several factories in Spain and France that produced luxury cars, aircraft en ...

HS 42 V8 driving a pusher propeller, was mounted on struts above the hull. SIAI proposed an armament of two fixed, forward-firing 7.7-millimeter (0.303-inch) Vickers machine guns mounted on the hull on either side of the

cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a Pilot in command, pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the ...

. The S.58 made its first flight early in the summer of 1924 and on 25 August 1924 set a world altitude record for aircraft of its type by reaching 5,831 meters (19,130 feet) with a payload of 250

kilogram The kilogram (also kilogramme) is the unit of mass in the International System of Units (SI), having the unit symbol kg. It is a widely used measure in science, engineering and commerce worldwide, and is often simply called a kilo colloquially ...

s (551 pounds). SIAI built three prototypes, but the ''Regia Marina'' opted to save money by re-engining the Macchi M.7''ter'' to extend its service life rather than purchase a new aircraft. SIAI did, however, build at least one more S.58, which the ''Scuola di Alta Velocità'' (High Speed School) at Desenzano used.

S.58''bis''

SIAI later fitted the first S.58 prototype with a 313-kilowatt (420-horsepower)

Fiat A.20 The Fiat A.20 was an Italian aero-engine of the 1920s. It was a water-cooled V12 engine that was used by early versions of the Fiat CR.20 fighter and the Macchi M.41 seaplane. In 1923, FIAT built the A.15, a 430 hp (320 kW) water-co ...

V12, redesignating the re-engined aircraft the S.58''bis''. In 1927, the ''Regia Marina'' again held a contest for a replacement for the Macchi M.7''ter'', and SIAI entered the S.58''bis''. The ''Regia Marina'' found it impressive enough to make plans to procure 97 S.58''bis'' aircraft, but these plans were cancelled when the ''Regia Marina'' again chose as an economy measure to extend the M.7''ter''s service life by re-engining it, and no production order materialized for the S.58''bis''.

S.58''ter''

In the autumn of 1928, the S.58''ter'', a slightly modified S.58''bis'' also employing the Fiat A 20 V12 engine, flew for the first time. In 1929, the ''Regia Marina'' again organized a contest for an M.7''ter'' replacement, and SIAI entered the S.58''ter''. The S.58''ter'' lost out to the Macchi M.41''bis'' and did not win a production order.Green and Swanborough, p. 527.

Operators

; *

Regia Aeronautica The Italian Royal Air Force (''Regia Aeronautica Italiana'') was the name of the air force of the Kingdom of Italy. It was established as a service independent of the Royal Italian Army from 1923 until 1946. In 1946, the monarchy was abolis ...

* Regia Marina

Specifications (S.58''bis'')

Notes: *Time to 3,000 m (9,842 ft): 7.66 min

Notes

References

*Green, William, and Gordon Swanborough. ''The Complete Book of Fighters: An Illustrated Encyclopedia of Every Fighter Aircraft Built and Flown''. New York: SMITHMARK Publishers, 1994. . {{Portal bar, Italy, Companies, Aviation S.58 1920s Italian fighter aircraft Single-engined tractor aircraft Biplanes Aircraft first flown in 1924