This single-seater low wing motor glider was the first of a series of such types designed by M Rene Fournier to go into production, and to be built by several different companies in France and Germany.
The RF3 was developed from the prototype Avion-Planeur, known as the Fournier RF01, which first flew on 6 July 1960. It proved to be so successful that the French Government helped to finance the building of two RF2 pre-production prototypes, the first of which flew in June 1962, and later ordered six of the production version, the RF3, with 34 hp Rectimo-VW engine, for national flying clubs; the first RF3 made its maiden flight in March 1963 and received its Cof A on7 June that year.
A second prototype of the RF-01 was built, and then Fournier entered into partnership with Antoine d'Assche, who was then producing Jodel two-seaters in a hangar at Gap in the French Alps under the trade name of Alpavia. They produced quite a number of the little airplanes, which were not exactly powered sailplanes but airplanes with an unusually shallow angle of glide; successive improvements brought about the RF4 (the second prototype having been the 2, and the original production version the 3 with Volkswagen engine).
Of all-wood construction, the RF3 has a single spar one-piece wing with 4° dihedral and plywood and fabric covering, attached to the fuselage by four bolts. The ailerons are fabric-covered and there are no flaps, but instead a three-section air brake in the upper surface of each wing inboard of the ailerons. The wooden fuselage is plywood-covered, the pilot sitting under a moulded one-piece canopy; radio and oxygen equipment are among the optional 'extras'. The monowheel has rubber chord shock absorption and retracts forward manually into a glassfibre cowling; it has a manually-operated brake and is supplemented by a hoop-shaped balancer skid of 6mm steel wire under each wing. There is also a steerable tailwheel. The cantilever wooden tail unit has a trim tab in the rudder.
Rene Fournier entered into partnership with Comte Antoine d'Assche of Alpavia SA, which had been building Jodel D117s, and this firm took on the production of the RF3, building a total of 95 in all; deliveries started in November 1963. Although the engine can be stopped and restarted in flight and the RF3 is capable of prolonged soaring flights – many such flights of up to five hours have been made – the type should not be regarded as just a powered sailplane, as it has a high performance and is capable of all simple aerobatic manoeuvres such as stall turns, loops, half-rolls, slow rolls and spins.
This performance was soon being proved in service, one notable flight in the winter of 1963-64 being made by an RF3 pilot over St Auban in the Basses-Alpes region, who climbed to 19,700ft after stopping his engine at 6,500ft. Another RF3 was successfully operated in the French Alps with a mono-ski landing gear replacing the retractable monowheel. The engine is a 39hp modified version of the Volkswagen 1,200cc 'flat four' car engine, converted by the Rectimo Co of Chambery. The only modifications are the fitting of a special Zenith carburettor, a propeller shaft and a Bendix magneto of the type used on the 65hp Continental engine. For restarting in flight, an optional mechanical system pushes the four exhaust valves in simultaneously, enabling the propeller to start the engine during a dive at 90mph; a two-blade wooden prop made by Evra or Helice Legere is fitted, and there is a single 6.5 Imp gallon fuel tank in the fuselage.
Span: 36 ft 9 in
Length: 19 ft 8 in
Wing area: 118.0 sqft
Aspect ratio: 11.0
Empty weight: 529 lb
Max weight: 772 lb
Max level speed: 118 mph
Max cruising speed: 112 mph
Min sinking speed: 3.94 ft/sec
Take-off run to 50ft: 875 ft
Range with max fuel: 310 miles