The Koolhoven F.K.51 was a 1930s Dutch two-seat basic training biplane built by the Koolhoven Company.
The F.K.51s were in active use in Royal Dutch Flight Schools during the first months of World War II in the training of young Dutch pilots, but with the German invasion of the Netherlands in May 1940, the F.K.51s were deemed obsolete and most never took to the air being too slow and vulnerable. The majority of F.K.51s were destroyed on the ground by attacking Luftwaffe aircraft.
