Weiss MW 9K Mistral
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 Gnome-Rhône 7K itself was an enlarged version of the Gnome-Rhône 5K which was derived from a licensed version of the Bristol Titan . A redesign of the cylinders is indicated by the K suffix. 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). The engine was used successfully in the MÁVAG Héja and Weiss WM-21 Sólyom aircraft.
Licence production in Romania by Industria Aeronautică Română (IAR) was carried out as the I.A.R. 9KIc40.