The "Colombo" brand is a product of "Officine Meccaniche", but the construction was carried out at Alfa Romeo SpA in Milan, as they were licensed to do so.

-During WWI they were used in great quantity by the Italian Air Force, and were also built by Bianchi. It is said that they were also by De Vecchi and CMN as well. (See both).

-De Vecchi was Officine Meccaniche De Vecchi (OM) and they designed the engines.

-Going back we find that in 1915 appeared the 106C-6, with six cylinders inline, liquid-cooled, giving 100 CV of power.

-The C model was of equal architecture and gave 160 CV.

-The D model of 1916 was the well-known D-110, that gave 110 CV with the same six cylinders inline, reaching until 115 CV.

-The E model would be similar but with 150 CV.

-After that there is a jump in time, until 1928 in which appears the four-cylinder, inline, upright S.53, now air cooled.

-This new line of engines appear as from "Officine Colombo SA", giving about 94 CV at 1,900 rpm. For this engine we have more photographs.

"Colombo S.53"

"Colombo S.53, rear view"

-And also of a drawing of the right side.

-The designers were Mr. Colombo and Luva in 1927, the year in which they produced the first engine, the upright, four-cylinder S.53 that gave 80/85 CV and was cooled by air.

"Colombo S.53"

-This engine was mainly installed on the Macchi M-70.

-The S.63 is derived from the S.53 but with six cylinders, and was also an inline engine. It is said that these engines were mass built.

"S.63 diagram"

-The S.63 was air cooled. It had a simple and robust construction with low rotation speed. In the beginning the power output was in the order of 115 to 120 hp, and in 1938 it already reached 130 CV.

-These engines were installed on the Breda BA-15, -33, -39 and -44. Also on the Caproni 100 and 125, and the Macchi MCA-3.

-The S.63 is from 1930. It had six cylinders, was air cooled and gave 130 CV at 1,850 rpm.

"Colombo S.63"

-Another model, not less known, was the Colombo D.110 that gave 130 CV and flew in the Breda A-4 and A-2.

"Colombo D.110"

-The Colombo engines, in addition to being manufactured by Alfa Romeo, they were also made by Bianchi. As we said, the design is from "Officine Meccaniche Nazionale de Vecchi" in Milan.

"Officine Meccaniche Logo"

-More views of the Colombo S.53 and S.63 engines. Both with the same architecture but the former with four cylinders and the latter with six.

"Colombo S.53"

"Colombo S.63"

From Appendix 10: The S.53 four-cylinder inline upright engine in the main text can be supplemented with a front view.

"Colombo S-53 side view"

"Colombo S.53, front view"