Leduc RL.21

Between 1939 and 1975 the amateur aircraft designer and builder René Leduc (not the ramjet designer of the same name)^{[citation needed]} completed and flew five different lightplanes, two of which set records in their class.^[1][2][3] The RL.21 was a low wing monoplane with its wings braced to the upper fuselage by a pair of inverted-V struts. It was powered by a 101 kW (135 hp) SNECMA-Régnier 4L-00 four cylinder inverted air-cooled inline engine driving a two blade propeller. A low, smoothly streamlined canopy covered the single seat cockpit and merged aft into a raised rear fuselage. The empennage was conventional. The RL.21 had a tailwheel undercarriage with spatted main wheels on cantilever legs, mounted on the wings approximately below the ends of the wing struts.^[4]

Leduc built the RL.21 over a period of six years with assistance from Sud Aviation and from the Nantes Technical School. It flew for the first time in August 1960.^[4] Between late 1960 and early 1967 it set seven records in its C1a and C1b categories,^[3] respectively for aircraft with maximum take-off weights below 500 kg (1,102 lb) and between 500–1,000 kg (1,102–2,205 lb).^[2] The earliest were for speeds of 313.5 km/h (194.8 mph) and 316.2 km/h (196.5 mph) for the two classes around a 100 km (62 mi) closed circuit ^[2] and the last at 349.2 km/h (217 mph) and 334.7 km/h (208 mph) over a 500 km (311 mi) closed circuit.^[3] Throughout these flights the pilot was Raymond Davy.^[4]

Data from Gaillard (1990) p.209^[4]

General characteristics

• Capacity: One
• Length: 6.90 m (22 ft 8 in)
• Wingspan: 5.70 m (18 ft 8 in)
• Wing area: 6.5 m² (70 sq ft)
• Empty weight: 390 kg (860 lb)
• Max takeoff weight: 500 kg (1,102 lb)
• Powerplant: 1 × SNECMA-Régnier 4L-00 4 cylinder inverted air-cooled inline, 101 kW (135 hp)
• Propellers: 2-bladed

Performance

• Maximum speed: 360 km/h (220 mph, 190 kn)
• Service ceiling: 8,000 m (26,000 ft)