Fournier’s plant in central France was shut down as unable to compete with the French Government. Fournier’s motorgliders were still being manufactured in Germany.
The RF5 is basically a tandem two-seater version of the RF4D and RF3, differing from them mainly in having wings of increased span, with folding outer sections to facilitate hangar storage, and a more powerful engine. The wood and fabric, two in tandem RF5 is a sailplane with a single main wheel, and tip outriggers. The wings fold inboard at their halfway points to reduce hangar space; the locking pins for the wing fold are easily checked from the cockpit. There are glider style spoilers and a five piece snap in harness, to encourage aerobatics. Dual controls are fitted, the pupil sitting in the forward seat when under instruction, this seat being occupied by the pilot when the aircraft is flown solo. The pilot and pupil or passenger sit under a one-piece sideways-hinged Plexiglas canopy, with a small baggage space aft of the rear seat; rudder pedals are adjustable and the canopy can be jettisoned in emergency.
The wings are very similar structurally to the RF4D’s with slightly less dihedral (3° 15′) at the main spar centre-line; the outer wing panels fold inwards, and the same type of metal-skinned spoilers are fitted in the upper surfaces. The wooden oval-section fuselage is made up of bulkheads and stringers, and is ply and fabric covered. The cantilever wooden tail unit is similarly covered, and has a fixed-incidence tailplane with a Flettner trim tab in the port elevator; the entire tail can be removed for transportation. Landing gear is similar to the RF4D’s, the single Tost mainwheel having twin oleo-pneumatic shock absorbers and a manually-operated brake and retracting forward with spring assistance; there is a steerable tailwheel with oleo-pneumatic shock absorber, and small outrigger wheels under each wing, just inboard of the fold line. The powerplant is a 68hp Sportavia-Limbach SL 1700E Comet ‘flat four’ engine with a maximum continuous rating of 63hp and driving a Hoffman two-blade fixed-pitch metal propeller of 4ft 9.75in diameter. Two metal fuel tanks in the wing root leading edges give a total capacity of 13.8 Imp gallons. The converted 68 horsepower Volkswagen engine has single ignition, despite which the Fourniers are generally certificated throughout Europe; the FAA alone won’t approve it.
Construction of the prototype RF5, registered D-KOLT, was started in the summer of 1967, and it first flew in January 1968. The RF5 received its German domestic type certification in the powered sailplane category in March 1969. Production started late 1968, and a total of 145 RF5s had been delivered by the end of 1978; production ended in the spring of 1979.
The RF5’s maximum cruise is 102 knots. Consumption is about four gallons per hour, for an endurance of four hours and a range of about 410 nautical miles. Best glide ratio is 22/1, and minimum sink is 4.6 feet per second: not bad, considering the fixed pitch non-feathering prop. The RF-5 has an electric starter.
Aerobatics are glider like but it’s hard not to exceed the 145 knot redline. The approach is best flown as a sailplane: leave the power alone and control your descent with the spoilers. The spoilers reduce lift as well as increasing drag and should be all the way out as you cross the fence; deployng them fully just as you round out can knock the tailwheel off or jam the main so it won’t retract.
Some 150 RF5s have been built by Sportavia, a company partly owned by VFW Fokker. Their production includes the RF5B Sperber.
The RF5B Sperber (or Sparrowhawk) is an improved version of the RF5 differing from it chiefly in having the wing span increased by 10ft 9in and the rear fuselage cut down to give improved rearward visibility from the new bulged sideways-opening cockpit canopy, and to reduce the side area. The wing is an all-wood single-spar structure with plywood and fabric covering. The RF-5B outer wing sections fold to reduce the span to 11.3 m/ 37 ft for hangers, and features outrigger wheels for taxiing, spoilers and a full electrical system and a shorter fuselage. There is space for 5 kg (11 lb) of baggage behind the rear seat. The fuselage is an all-wood oval section structure of bulkheads and stringers covered with a plywood skin and the two pilots sit in tandem beneath a one-piece Plexiglas canopy hinged sideways. Powered by a 50.7 kW (68 hp) Sportavia Limbach SL 1700E Comet engine it has a choice of two types of Hoffmann propeller: a 1.45 m (57 in) diameter two-blade fixed-pitch, or a 1.5 m (59 in) diameter two-blade three-position variable pitch propeller. Fuel is carried in wing-root leading edge metal tanks with a total capacity of 38 litres (8.4 Imp gal).
Construction of the prototype began in early 1971 and it first flew in May of that year. The RF5B received German certification in the motor glider category in March 1972, and by the spring of 1977 a total of 80 RF-5Bs had been delivered; from 1979 it was only available to a firm order.
In 1973 several modifications were introduced on production aircraft including an improved cabin heating system; an engine muffler to decrease exterior and cabin noise levels; an adjustable ventilation system; optional disc brakes and a wider range of instrument and equipment optional ‘extras’, which included an artificial horizon, electric compass and a flight data computer. The same 68hp Sportavia-Limbach SL 1700E Comet engine as on the RF5 is fitted, although the SL 1700E1 of the same horsepower could be fitted optionally, this variant being equipped to drive the Hoffman HO-V62R two-blade three position variable-pitch propeller that was available as an alternative to the fixed-pitch prop. All fuel was then contained in a single fuselage fuel tank of 8.6 Imp gallons capacity.
The RF55, which first flew in 1972, was a modified version of the RF5B fitted with a slightly-modified 60hp Franklin 2A-120-A engine to meet overseas certification requirements; an electric fuel pump was featured, as well as a larger fuel tank; this version did not go into production.
The RF5D is an improved 1974 model of the RF5 incorporating the full range of improvements introduced on the RF5B Sperber in 1973, and with a more powerful (74hp) Sportavia-Limbach SL 1700ED engine.
RF-5
Engine: 59 kw/80hp Limbach L 2000 EOI
Wing span: 13.74 m / 45 ft 1 in
Wing area: 15.12 sq.m / 162.8 sq.ft
Length: 7.80 m / 25 ft 7.25 in
Height: 6 ft 5 in
Empty Weight: 420 kg / 926 lb
MTOW aerobatic: 660 kg / 1333 lb
MTOW utility: 650 kg / 1455 lb
Wing Load: 42.8kg/sq.m / 8.77lb/sq.ft
Water Ballast: 0kg / 0lb
Aspect ratio: 12.25
Min sinking speed: 4.59 ft/sec
Best glide ratio: 22:1
Airfoil: NACA 23015 @ root, 23012 @ tip.
Max level speed: 124 mph at sea level
Max cruising speed: 118 mph / 102 kt / 190 kph
Service ceiling: 19,675 ft / 6000 m
Take-off run: 655 ft
Range with max fuel: 472 miles / 410 nm / 760 km
No. of Seats: 2
Baggage capacity: 22 lb / 10 kg
Sportavia RF5B Sperber
Engine: Limbach SL 1700E, 51kW/68 bhp
Span: 17.02m / 55 ft 10 in
Length: 7.71 m / 25 ft 3.25 in
Height: 1.96 m / 6 ft 5 in
Wing area: 19 sq.m / 204.5 sq ft
Aspect ratio: 15.25
Airfoil: NACA 23015/23012
Folded span: 35.8ft.
Empty weight: 470kg /1036lb
Max weight: 680kg /1499lb
Payload: 210kg /463lb
Wing Load: 35.7kg/sq.m /7.31lb/sq.ft
Max level speed: 118 mph / 102 kt / 190 km/h
Max cruising speed: 112 mph
Stall speed: 37 kt / 68 km/h
L/DMax: 26 at 98 kph / 53 kt / 61 mph
Min sinking speed: 0.89 m/s / 2.92 ft/sec / 1.73 kt at 46.5 mph / 40.5 kt / 75 km/h
Max rate of climb at S/L: 180 m/ min / 590 ft/min
Take-off run: 187 m / 615 ft
Range with max fuel: 261 miles / 420 km / 227 nm
No. of Seats: 2
RF55
Engine: Franklin 2A-120-A, 60 hp
All Aero 