The Rhein-Flugzeugbau RF-1 was a prototype channel wing aircraft.
The RF-1 is a modification of the channel wing concept, that uses a single channel and propeller to eliminate the asymmetrical lift issues with a twin channel wing design. The "channel" is an airfoil-shaped section along the lower arc of the rearward propeller that produces additional lift from the propwash. The RF-1's propeller was completely shrouded, creating a hybrid ducted propeller. Twin engine redundancy is maintained with multiple engines driving a central propeller with freewheeling clutches to allow for an engine failure.
The aircraft had the unique shape to facilitate a channel wing design. The fuselage was composed of welded steel tubing with a composite skin. The landing gear was electrically retractable.
The prototype was built at Krefeld/Mönchengladbach and was only flown once.