The RFB/Grumman American Fanliner was an experimental German light aircraft of the 1970s, propelled by a piston engine driving a ducted fan.

In the 1960s, Hanno Fischer, Technical Director of Rhein-Flugzeugbau (RFB), developed an interest in aircraft powered by ducted fans integrated into the aircraft structure, flying two modified gliders as testbeds, a VFW-Fokker FK-3 fitted with an eight-bladed ducted fan in the rear fuselage, which flew as the Sirius I in 1969, and a Caproni Vizzola Calif A-21, which flew as the Sirius II on 16 December 1971.

The rear fuselage, which carried a T-tail, consisted of a narrow boom extended behind the fan duct, supported by triangular-section beams in a cruciform arrangement.

The use of a three-bladed fiberglass fan, with swept blades driven via a gearbox allowed noise levels to be reduced to well below the German statutory limits for light aircraft.

[5] The first prototype Fanliner, D-EJFL with makers number 001, was exhibited at the June 1975 Paris Air Show.