Gnome-Rhône 14K

Mistral Major
Gnome-Rhône 14Ks in a hangar in North Africa, 1943
Type	Radial engine
Manufacturer	Gnome et Rhône
First run	1929

The Gnome-Rhône 14K Mistral Major was a 14-cylinder, two-row, air-cooled radial engine. It was Gnome-Rhône's major aircraft engine prior to World War II, and matured into a highly sought-after design that would see licensed production throughout Europe and Japan. Thousands of Mistral Major engines were produced, used on a wide variety of aircraft.

In 1921 Gnome-Rhône purchased a license for the highly successful Bristol Jupiter engine and produced it until about 1930, alongside the smaller Bristol Titan. Starting in 1926, however, they used the basic design of the Titan to produce a family of new engines, the so-called "K series". These started with the 5K Titan, followed by the 7K Titan Major and 9K Mistral. By 1930, 6,000 of these engines had been delivered.

However, the aircraft industry at that time was rapidly evolving and producing much larger aircraft that demanded larger engines to power them. Gnome-Rhône responded by developing the 7K into a two-row version that became the 14K Mistral Major. The first test examples were running in 1929.

As the Jupiter had set the pattern for one-row radials in the 1920s, the Mistal Major became a canonical design for twin-row radials of the 1930s. It was widely licensed and formed the basis for many successful designs. Among the licensees were Industria Aeronautică Română, Manfred Weiss in Hungary, Alvis of the UK, Tumansky in the USSR, Walter of Czechoslovakia, Isotta-Fraschini and Piaggio in Italy. Nakajima in Japan also licensed it, but did not put it into production, developing their own designs based on features taken from the Mistral and other designs.

...
Wikipedia