The Gnome-Rhône 9K Mistral was a nine-cylinder 550 hp (405 kW) to 700 hp air-cooled radial engine, that started life as an enlarged Gnome-Rhône 7K with two extra cylinders.

The 9K was followed by the larger and more powerful 14-cylinder twin row Gnome-Rhône 14K.

The 9K was license produced by Hungarian company Weiss Manfréd Repülogép- és Motorgyár Rt.

(WM Rt, the aircraft engine factory of Manfred Weiss).

Only small numbers were built and it was dropped in favor of the M-25 a version of the Wright Cyclone and the M-85 a version of the Gnome-Rhône 14K Mistral Major.