M.Hardy. Gliders & Sailplanes of the world

VFW-Fokker FK-3

  This high performance Open Class single-seater, distinguished by a pod-and-boom fuselage and a very tall fin and rudder, was designed by Dipl-Ing Otto Funk and the prototype was built by apprentices at VFW-Fokker's Speyer plant in Germany in the course of their regular training. It first flew on 24 April 1968 and production started in January 1969, soon building up to a rate of three or four per month. Designed especially for weak thermal conditions, the FK-3 is characterised by ease of handling; in its first competition, flown by Dr Rolf Spanig, the prototype won the Open Class in the 1968 Italian Championships, and two FK-3s later gained first and second places in the Austrian Championships. The cantilever shoulder wings have a thickness/chord ratio of 15.3% and are of an unusual metal and foamed honeycomb construction, bending loads being carried by a single metal spar which tapers from a T-section to a U profile, and drag and torsion loads being carried by a light alloy nose spar which transmits these loads to the fuselage fittings. The wing ribs are of light alloy and plastic foam sandwich construction, spaced at intervals of approximately 4ft 7in, and supporting a 0.5mm thick light alloy skin. Between the ribs a foamed honeycomb known as Conticell 60 gives additional support to protect the skin from minor damage, and the overall wing finish is very smooth. The camber-changing flaps are divided into inner and outer sections and Schempp-Hirth air brakes are fitted. Up to 110lb of water ballast can be carried if desired in two rubber tanks in the wings with the dump valve positioned in the fuselage aft of the retractable monowheel. The fuselage nose section is of steel tube construction covered with a glassfibre-reinforced shell, and the tail boom, of small cross section, is built of riveted light metal sheet without frames or stringers, the lower part incorporating a rubbing strip to minimise damage in a rough landing. The tail unit is similar in construction to the wings, the rudder being fabric-covered. The monowheel is manually-retracted and has a drum brake; there is also a tailwheel. The pilot sits in a semi-reclining position on an adjustable seat and has adjustable rudder pedals; the long one-piece Plexiglas canopy is removable, except for a small front portion.


Span: 57 ft 1 in
Length: 23 ft 7 1/2 in
Height over tailplane: 5 ft 11 in
Wing area: 148.54 sq ft
Aspect ratio: 22.0
Empty weight: 529 lb
Max weight: 882 lb with water ballast
Max speed: 168 mph
Max aero-tow speed: 87 mph
Min sinking speed: 1.64 ft/sec at 40 mph
Best glide ratio: 42:1 at 55 mph