 11s were equipped with the British-designed Armstrong Siddeley Panther II radial engine, the first 14 of which were made in the United Kingdom.From 1934 license manufacturing of the Armstrong Siddeley Panther II began in Norway at Marinens Minevesen in Horten, with F.314 being the first aircraft equipped with a Norwegian-made engine.As the handmade Norwegian power plants were installed they soon proved to be of superior quality to the machine manufactured originals.