 Only Klingenberg, managing director of the Kjeller Aircraft Factory, had a negative opinion of the design, being especially critical of the choice of a relatively weak engine.The manufacture of parts for the prototype M.F.9 began in August 1924 and the wing construction was tested at an aeronautical institute in Göttingen in the German Weimar Republic, as well as being brought to breaking point in Horten.The Royal Norwegian Navy required the aircraft to have a top speed of 200 km/h, reach an altitude of 3,000 metres in 12 minutes and have a sturdy construction able to endure dog fighting.