In 1939, production of 100 Hurricanes was initiated in Yugoslavia by Zmaj and Rogožarski. Of these, 20 were built by Zmaj by April 1941. Recognising that the supply of British-made Merlin engines might not be guaranteed, it was decided to fit one of the Yugoslavian Hurricanes with a Daimler-Benz DB 601 engine instead; this aircraft was test flown in 1941. In 1938, a contract for 80 Hurricanes was placed with Fairey's Belgian subsidiary Avions Fairey SA for the Belgian Air Force; it was intended to arm these aircraft with an arrangement of four 13.2 mm Browning machine guns. Three were built and two flown with this armament by the time of the "Blitzkrieg" in May 1940, with at least 12 more constructed by Avions Fairey armed with the conventional eight rifle calibre machine gun armament.