The SPA 6A is an Italian water-cooled inline six-cylinder

aero engine An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Aircraft using power components are referred to as powered flight. Most aircraft engines are either piston engines or gas turbin ...

of the

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

era. The SPA 6A is mostly known for its use in the

Ansaldo SVA The Ansaldo SVA (named for Savoia-Verduzio-Ansaldo) was a family of Italian reconnaissance biplane aircraft of World War I and the decade after. Originally conceived as a fighter, the SVA was found inadequate for that role. Its impressive spe ...

high speed

reconnaissance In military operations, military reconnaissance () or scouting is the exploration of an area by military forces to obtain information about enemy forces, the terrain, and civil activities in the area of operations. In military jargon, reconnai ...

aircraft.

Design and development

The Societa Piemontese Automobili (SPA) of

Turin Turin ( , ; ; , then ) is a city and an important business and cultural centre in northern Italy. It is the capital city of Piedmont and of the Metropolitan City of Turin, and was the first Italian capital from 1861 to 1865. The city is main ...

, Italy started building aircraft engines in 1908 and prior to 1916 had built flat, vee and

radial Radial is a geometric term of location which may refer to: Mathematics and Direction * Vector (geometric), a line * Radius, adjective form of * Radial distance (geometry), a directional coordinate in a polar coordinate system * Radial set * A ...

engines. In 1916 SPA began manufacturing a

straight-six engine A straight-six engine (also referred to as an inline-six engine; abbreviated I6 or L6) is a piston engine with six cylinders arranged in a straight line along the crankshaft. A straight-six engine has perfect primary and secondary engine balanc ...

known as the 6A. The SPA 6A was designed with steel cylinders arranged in pairs with a common welded water jacket. The type made use of relatively advanced features such as aluminium pistons and a 6 degree overlap in valve timing. The engine was ordered into mass production by the Italian Military Aviation Technical Division to equip the Ansaldo SVA aircraft. In addition to production by SPA, the 6A engine was manufactured by Ansaldo, Breda, Talomona and Industrie Mecchaniche e Ferroviarie of

Arezzo Arezzo ( , ; ) is a city and ''comune'' in Italy and the capital of the Province of Arezzo, province of the same name located in Tuscany. Arezzo is about southeast of Florence at an elevation of Above mean sea level, above sea level. As of 2 ...

. The Ansaldo SVA was one of the fastest aircraft of WW1 with a top speed of . During WW1, Anasaldo SVAs made a sensational

flight over Vienna The Flight over Vienna was an air raid during World War I undertaken by Italian poet and nationalist Gabriele D'Annunzio on 9 August 1918. With 11 Ansaldo SVA aircraft from his team, the 87ma ''squadriglia'' (squadron) called ''La Serenissim ...

to drop

propaganda Propaganda is communication that is primarily used to influence or persuade an audience to further an agenda, which may not be objective and may be selectively presenting facts to encourage a particular synthesis or perception, or using loaded l ...

leaflets. Other famous exploits of the Ansaldo SVA included a 1920

Rome Rome (Italian language, Italian and , ) is the capital city and most populated (municipality) of Italy. It is also the administrative centre of the Lazio Regions of Italy, region and of the Metropolitan City of Rome. A special named with 2, ...

Tokyo Tokyo, officially the Tokyo Metropolis, is the capital of Japan, capital and List of cities in Japan, most populous city in Japan. With a population of over 14 million in the city proper in 2023, it is List of largest cities, one of the most ...

flight and a 1919 crossing of the

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

. Around 3,000 SPA 6A engines were produced in three variants: normal, semi super-compressed and super-compressed. Engines of this type remained in service until the 1930s.

Variants

;SPA 6A Normal: Originally rated for at 1,600 rpm with a displacement of and a weight of . Maximum power . ;SPA 6A Semi-Super-Compressed: Identical to the normal 6A, but with the cylinder bore increased to , and with a capacity of . Rated for but could develop at 1,700 rpm. ;SPA 6-2-A Super-Compressed: Displacement bore increased to bore and stroke, with a weight of . Rated at but could develop at 1,850 rpm.

Applications

* Ansaldo A.1 Balilla *

* Bartel BM.5 * Breda A.2 * Breda A.3 * Breda A.9 and A.9bis * CANT 7ter * Caproni Ca.66 * Gabardini G.9 * SIAI S.50

Specifications (6A Normal)

References

{{Reflist 1910s aircraft piston engines Straight-six engines

Design and development

Variants

Applications

Specifications (6A Normal)

See also

References