It has been developed from a mixed structure, fabric covered aircraft to a wholly composite machine. It remains in production at factories in Germany and Poland and has sold in large numbers, flying in four continents. The Fk9 is a conventionally laid out high wing, single-engine ultralight, with side-by-side seating and a fixed undercarriage. The wings have parallel chord and are fitted with ailerons and three-position flaps. They are braced with a single faired strut to the lower fuselage on each side. In the Mark 1 and 2 models, the wings were composite structures with fabric covering; later models have had all-carbon composite wings apart from aluminium control surfaces. There is now the option of an all-carbon fibre wing. The early Fk9 marks also had a steel tube, fabric covered fuselage, but this has been replaced with an all-glass fibre structure, apart from a steel cabin frame. Access to the dual control cabin, which has overhead transparencies,[5] is via top-hinged doors on each side. The fin and rudder are swept, mostly on the leading edge; the elevators are horn balanced. A tricycle undercarriage is standard, with (usually) spatted mainwheels on spring cantilever legs mounted on the fuselage at the base of the wing struts plus a spatted, steerable nosewheel. The mainwheels have brakes operated by a central hand control.[5] A conventional undercarriage is an option, with the mainwheel legs fuselage-mounted further forward, below the cabin doors, plus a carbon-and-steel tailwheel. A variety of engines have been fitted. Early models used a 26 kW (35 hp) Rotax 447 or Jabiru, or a (37 kW) 50 hp Rotax 503.[6] The Mark 3 had a 60 kW (80 hp) Rotax 912 UL and the Mark IV offers a choice between this engine, the uprated 73 kW (99 hp) Rotax 912 ULS or a 75 kW (100 hp) Ecofly M160, first used in production Fk9s in the Smart variant. The design is an accepted Federal Aviation Administration special light-sport aircraft. For operational history and details of the 8 variants, click here. Specifications below are for the Mark IV variant.
