SIAI S.52

SIAI

Industry	Aerospace
Founded	1915
Founder	Alessandro Marchetti
Headquarters	Italy

The SIAI S.52 was an Italian fighter prototype that first flew in 1924.

Design and development

In 1919, Alessandro Marchetti (1884–1966) created the Marchetti MVT fighter, which was renamed the SIAI S.50 in 1922 after Marchetti became chief designer at the SIAI company. The S.50 was submitted to the 1923 Regia Aeronautica (Italian Royal Air Force) fighter competition, although it was equipped with a 212-kilowatt (285-horsepower) SPA 62a six-cylinder engine rather than the 224-kilowatt (300-horsepower) Hispano-Suiza HS 42 eight-cylinder water-cooled engine specified by the Italian Air Ministry for the contest. Despite this deviation, the Regia Aeronautica showed sufficient interest to purchase three S.50 units from SIAI for testing, but plans to order a dozen more did not materialize.

To meet the Air Ministry's engine requirement, Marchetti developed an evolution of the S.50 powered by the HS 42 engine specifically for the 1923 fighter competition. This new model, designated the S.52, featured a single-seat, all-metal biplane configuration with its fuselage positioned between the upper and lower wings. The rear section of the fuselage was flattened to function as an airfoil. Its semi-elliptical wings were notably thinner and larger in surface area compared to those on the S.50, utilizing ailerons for roll control instead of the wing warping system employed on its predecessor. The all-moving tail surfaces of the S.50 were replaced by a conventional tail assembly combining fixed and movable components in the S.52. A two-bladed propeller was driven by the engine, and armament consisted of two synchronized, fixed forward-firing 7.7-millimeter (0.303-inch) Vickers machine guns mounted to fire through the propeller arc.

Operational history

The S.52 missed the 1923 fighter competition, as its maiden flight occurred in 1924. Two prototypes, identified as MM.3 and MM.4, were constructed; however, no production contract was awarded by Italy.

In 1925, there was a suggestion to equip one prototype with a 306-kilowatt (410-horsepower) Fiat A 20 engine, which was expected to enable a maximum speed of 285 kilometers per hour (177 miles per hour). This engine upgrade was never implemented.

One of the prototypes was transported to Latin America for demonstration purposes, including a notable 1927 flight from Argentina to Paraguay. After discovering that the Paraguayan Air Arm was procuring aircraft, SIAI conducted a series of successful demonstration flights at Paraguay’s Military Aviation School. Consequently, the Paraguayan government acquired the S.52 in 1927—marking their first-ever fighter purchase and remaining their sole fighter until they obtained seven Wibault 73 C.1 planes in 1928. No further orders for the S.52 followed.

The Paraguayan S.52 was assigned the serial number 16 in 1932. It apparently did not engage in combat during the Chaco War (1932–1935) but was heavily utilized as a fighter trainer at Paraguay’s Ñu-Guazú Military Aviation School. The aircraft was lost in an accident on 8 May 1933 at Ñu-Guazú airfield; its pilot, Lieutenant Emilio Rocholl, survived the incident.

Operators

Template:Country data Kingdom of Italy

• Regia Aeronautica

Template:Country data Paraguay

• Paraguayan Air Arm

Specifications

Template:Aircraft specs Notes:

• Time to 1,000 m (3,281 ft): 1 min 30 sec

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. ISBN 0-8317-3939-8.
• Sapienza Fracchia, Antonio Luis. La Contribución Italiana en la Aviación Paraguaya. Author's edition. Asunción, 2007. 300 pp.