Aviation Engines
Curtiss Aeroplane & Motor Corporation

Of the three engine manufacturers who were left in business after the signing of the Armistice at the end of WW1 (Curtiss, Wright and Packard) only Curtiss had been involved in the manufacture of aircraft engines before WW1. Except for a few experimental engines, all were water-cooled types, and these were not built in large quantities until 1914 when the UK Government ordered severeal hundred of the 90hp OX engine. A slightly larger 100 hp OXX engine was also produced but these OX and OXX engines were only suitable for trainer aircraft, and were obsolete by the end of the war.

Curtiss OXX-3 Aero Engine

Curtiss OXX-3 Aero Engine

During 1916, Curtiss brought out the 1145 cu in water cooled K-12 engine, which produced about 400hp. The further development of this engine was held up by the decision of the US Govt in having only one standardised 400hp engine for its aircraft, the preferred type being the Liberty. Only in 1934 was the Army to stop the use of the Liberty engine in its aircraft in preference to other types.

Curtiss K-12 Aero Engine

Curtiss K-12 Aero Engine

Curtiss K-12 Aero Engine

After the end of the war Curtiss threw all its efforts into the development of the K-12, which then became the C-12. Reduction-gear problems forced a direct-drive version called the CD-12, and a further development made it into the D-12. This engine met with some considerable success, taking the world speed record in 1922 and going on to decome what was one of the best high-power aero engines at the time.

Curtiss V-2 Aero Engine

Requests from the Navy to develop a 200hp engine met with strong resistance from Curtiss, who, like Wright, had other things to get on with which were potentially more profitable. Half of the D-12 would have given Curtiss the basis of a 200hp six cylinder engine with little development, but the company deceided against going down that path.
The Army had in the meantime produced a specification for a new engine, known as the R-1454. The specification was issued on 15th August 1923. The development of the engine itself had been carried out by the Army through Wright, Lawrance and an independent engineer, S.D.Heron, and had been through many changes to the cylinders in particular. The fixed-price contract was won by Curtiss following its bid of the 13th November 1923 , and was for the construction of three engines with an option for three more. The first engine was delivered in September 1924, and it gave up to 405hp at 1650 rpm. A modified cylinder developed by Heron (Type M) was fitted to the engine, and the Army instructed Curtiss to proceed with the other engines called for under the contract in February 1926.
The appearance of the lighter Wasp engine from Pratt & Whitney effectively killed off the R-1454, and the Army and Curtiss agreed to terminate the contract almost at once. Curtiss then started development of the H1640, a two-row 12-cylinder engine which it hoped would capture the market for an engine in the power range of the Wasp, by having a smaller frontal area. Curtiss never recovered its position as a major engine manufacturer after this period, and left the field open to Pratt & Whitney and Wright Aeronautical in the big air-cooled radial engine markets. It did have continuing sales of the water-cooled Conqueror engine, sales which produced quite good profits for the company, and which in dollar terms equated to purchases of air-cooled engines by the Army. In 1932, Conqueror purchases by the Army equated to two thirds of expenditure on engines of this size.
In 1929, Wright and Curtiss merged to become the Curtiss-Wright Corporation.
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