Renard R-31 / R-32
In view of replacing the ageing Breguet XIX observation aircraft of the Aéronautique Militaire Belge, the Renard company developed a twin seat parasol-wing aircraft which in the first studies was designated as Renard RR (for Rolls-Royce). The renamed Renard R.31 was designed by Alfred Renard of Constructions Aéronautiques G. Renard to meet a requirement of the Belgian Air Force for a short ranged reconnaissance and army co-operation aircraft.
It was a parasol monoplane of mixed construction, powered by a Rolls-Royce Kestrel engine, with a welded steel tubing structure with metal sheet covering the forward fuselage and fabric covering of the remainder of the airframe. The wing was held in position by a single Vee strut on each side, conjoined with its fixed under carriage. Armament consisted of one or two forward-firing 7.62 mm Vickers machine guns and one 7.62 mm Lewis machine gun in flexible mount in rear cockpit. There was also a rarely used provision for dropping four 10 kg bombs under the wings.
Powered by a Rolls-Royce Kestrel II engine developing 487hp, it first flew at Haren airfield at Evere, near Brussels, on 16 October 1932, piloted by Renard test-pilot Charles Rooms.
The Aéronautique Militaire placed an order for 28 R.31s was placed in March 1934, with six to be built by Renard and the remainder by SABCA. One aircraft was fitted with a Lorraine Petrel engine for evaluation, but this was later replaced by the normal Kestrel engine.
After 1936 a second aircraft was fitted with an enclosed canopy and a Gnome-Rhône Mistral Major radial engine, becoming the R-32, with this then being replaced by a Hispano-Suiza 12Y engine, but the R-32 did not show sufficiently improved performance to gain a production order. The Renard R-32 was reworked as a normal R.31 thus becoming the 35th machine for the AéM.
A further six R.31s were ordered in August 1935 by the AéM. The aircraft received the military registrations N-1 to N-35.
The R.31 entered service with the Belgian Air Force in 1935, replacing the Breguet 19 in the 9e and 11e Escadrilles d'Observation based at Liège. In service, it was not popular, as it had poor handling, being vulnerable to entering flat spins if mishandled, with all aerobatics therefore being banned.
All the Renard R-31’s were used by the Bierset based observation squadrons - 9/V/1Aé (Sioux on blue circle) and 11/VI/1Aé (Sioux on red circle). At the start of the war 21 aircraft were available who were operational during the whole of the “18 day Campaign” flying their last mission on May 27th, 1940.
The R.31 was hopelessly obsolete, and those that were not destroyed on the ground in the early hours of the German Blitzkrieg invasion of Belgium in May 1940 were ravaged by German fighters as they bravely attempted to gather information on the German invasion. None apparently functioned as ground support aircraft during the brief Belgian Army resistance, flying 54 reconnaissance sorties in support of the Allied forces defending Belgium, with the last mission (which was also the final mission flown by the Belgian Air Force in its attempt to repel the Germans, being flown on the afternoon of 27 May 1940. Following the German occupation of Belgium, the Luftwaffe had no interest in the machines and those that had survived the initial onslaught were unused or were destroyed. Overall, these machines had no significant impact on the war although they were briefly involved.
As not a single Renard R.31 remains anywhere in the world, a number of volunteers at the Royal Army Museum at Brussels is building a 1/1 scale replica using the original blueprints.
Engine: 1 × Rolls-Royce Kestrel IIS V-12, 358 kW (480 hp)
Wingspan: 14.40 m (47 feet 2¾ inches)
Length: 9.20 m (30 ft 2 in)
Height: 2.92 m (9 ft 7 in)
Wing area: 32 m² (344 ft²)
Empty weight: 1,330 kg (2,926 lb)
Loaded weight: 2,130 kg (4,686 lb)
Maximum speed: 294 km/h (159 knots, 183 mph) at 4,000 m(13,120 ft)
Cruise speed: 238 km/h (129 knots, 148 mph)
Range: 650 km (351 nm, 404 mi)
Service ceiling: 8,750 m (28,700 ft)
Wing loading: 66.6 kg/m² (13.6 lb/ft²)
Power/mass: 0.17 kW/kg (0.10 hp/lb)
Climb to 2,000 m (6,560 ft): 5.5 min
Climb to 5,000 m (16,400 ft): 11.7 min
Armament: 2 or 3 7.62 mm Vickers machine guns