The Koolhoven F.K.42 was a parasol-wing, two-seat training monoplane manufactured by

Koolhoven N.V. Koolhoven was an aircraft manufacturer based in Rotterdam, Netherlands. From its conception in 1926 to its destruction in the Blitzkrieg in May 1940, the company remained the second major Dutch aircraft manufacturer (after Fokker). Althoug ...

in the Netherlands. Only one was built.

Design

The Koolhoven FK.42 was designed to train civilian pilots and enable them to gain their certificates rapidly on an aircraft similar to those low performance types they were likely to fly later, rather than slowly on specialised aircraft designed to train military pilots. The

Farman F.200 The Farman F.200 was a civil utility aircraft produced in France in the 1930s. Derived from the F.190, it featured a revised fuselage that did away with its predecessor's enclosed cabin. Instead, it was a parasol-wing monoplane with open cockpits ...

was built to the same end. Its one-piece, wooden parasol wing was built around two box spars and was covered in

plywood Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured ...

. On each side two parallel,

airfoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. ...

-section struts braced the wing from the lower fuselage to the spars, each pair only about from the centreline. The FK.42 was powered by an air-cooled, Cirrus Hermes four-cylinder inline engine, mounted upright in the nose. It was enclosed in an aluminum cowling and had a fuel tank in the central wing between the spars. The fuselage, like the wings, was all-wood; spruce

longeron In engineering, a longeron and stringer is the load-bearing component of a framework. The term is commonly used in connection with aircraft fuselages and automobile chassis. Longerons are used in conjunction with stringers to form structural ...

s and ply skin gave it flat sides and bottom but there was rounded upper decking. When it first appeared it had two open

cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a Pilot in command, pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the ...

s in tandem but quite soon the two were merged into a single cockpit. The trainer was flown solo from the rear seat; the pupil's forward position had deployable dual controls. The empennage was conventional, with the straight-tapered tailplane mounted on top of the fuselage and braced from below with a single strut on each side. The elevators were unbalanced. The fin was triangular and the rudder, again unbalanced and straight-edged, extended down to the keel through an elevator cut-out. The FK.42 had fixed tailskid landing gear with a large track of . The mainwheels were hinged on faired V-struts from the lower fuselage longerons and had long, vertical

shock absorber A shock absorber or damper is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy (typically heat) which is then dissipated. Most sh ...

struts to the forward spars at the top of the wing struts, strengthened there by two more short struts per side to the upper fuselage.

Operational history

The date of the FK.42's first flight is not known but it was registered on 5 June 1929 in the company name. Both the FK.42 and the larger, three-seat FK.41 were at the International Light Plane Meeting held in Rotterdam between 27 and 30 June 1929, where Frederick Koolhoven certainly flew the FK.41. Koolhoven, a cautious pilot, found the new trainer reassuring to fly and he took it to several other aircraft meetings. Despite the publicity, no sales were made and only one FK.42 was built. It remained with Koolhoven until February 1932, when it was re-registered to W. de Heer at Rotterdam. It was lost in a crash on 7 July 1932.

Specifications (FK.42)

References

{{Koolhoven aircraft 1920s Dutch civil aircraft F.K.42 Parasol-wing aircraft Single-engined tractor aircraft Aircraft first flown in 1929