1926-1940 N.V. Koolhoven Vliegtuigen
Koolhoven F.K.30 'Toerist'
Private plane with rotating wing for transport, 1927
Koolhoven F.K.35
Mono/biplane scout and fighter, 1926
Koolhoven F.K.36
Biplane fighter, enlarged version of the F.K.35, 1926
Koolhoven F.K.37
Three engined airliner, design for KLM (not built), 1927
Koolhoven F.K.39
Several design studies (not built), 1927
Koolhoven F.K.40
Airliner for 4 or 5 passengers, 1928
Koolhoven F.K.41
High winged sportscoupe, 1928
Koolhoven F.K.42
Private plane, 1929
Koolhoven F.K.43
Aircraft for three passengers, 1930
Koolhoven F.K.44 'Koolmees'
Private plane, 1931
Koolhoven F.K.45
Aerobatic plane, 1931
Koolhoven F.K.46
Trainer, 1930
Koolhoven F.K.47
Private plane and trainer, 1933
Koolhoven F.K.48
Airliner for six passengers, 1934
Koolhoven F.K.49
Photo- and cartography aircraft, 1935
Koolhoven F.K.49A
Multi purpose aircraft, 1937
Koolhoven F.K.50
Airliner for ten passengers, 1935
Koolhoven F.K.51
Military trainer, 1935
Koolhoven F.K.52
Scout and fighter, 1936
Koolhoven F.K.53 'Junior'
Light private plane with side by side seats, 1936
Koolhoven F.K.54
Executive plane, first Koolhoven with retractable gear, 1937
Koolhoven F.K.55
High performance fighter with many innovations, 1936
Koolhoven F.K.56
Military advanced trainer, 1937
Koolhoven F.K.57
Executive plane, 1938
Koolhoven F.K.58
High performance fighter, 1938
Koolhoven F.K.59 (no photograph available)
Military multi purpose aircraft, 1938
The type number F.K.59 has been used for three Koolhoven designs: a two-engined float plane, an open two-seat sports plane and a single engined military biplane developed from the F.K.52. Of these three aircraft it was the single engined biplane that made it to production as Koolhoven F.K.59. It was the last Koolhoven design in production.
Other sources mostly show a photo of the two-engined float plane as F.K.59, but this was just a mock-up, not an actual aircraft, neither a prototype.