By the 1930s, the French air force’s bomber force was very out-of-date and too small. In December 1936, a requirement was issued code-named “B4”, the French Air Ministry, for a new four-seat, twin-engined medium bomber design.
Breguet submitted four designs and Bloch one; of which a two-engine Breguet and four-engine Bloch design were both shortlisted. Breguet’s initial design, the Breguet 480 (or Bre. 480) to be powered with the specified 1,225 hp (914 kW) Gnome et Rhône 14L radial engines which was meant to carry 1,000 kg (2,200 lb) of bombs over a 2,500 km (1,600 mi) radius. Gnome et Rhône abandoned the 14L however, so, after considering a version powered by two Hispano-Suiza 12Y V12 engines, Breguet reworked the design as the Breguet 482, with four 1,350 hp (1007 kW) Hispano-Suiza 12Z engines, with an order for two prototypes placed by the French Air Ministry on 12 May 1938.
The Breguet 482 was a mid-winged monoplane of all-metal construction, with a clean, low-drag, oval section monocoque fuselage, twin tails and a retractable tailwheel undercarriage. The planned defensive armament was a 20mm Hispano-Suiza HS.404 cannon in a power operated dorsal position, with a 7.5mm machine gun in the nose and a further two machine guns in ventral mountings. Up to 2,500 kg (5,500 lb) of bombs could be carried.
The Br-482 was of all-metal construction with a four-man crew. The most characteristic feature was the large “glazed” nose area. The plane was fully-enclosed and had retractable main and tail landing gear. The internal wing supports were three spars, the outer two aluminium and the centre steel.
Construction of the two prototypes was well progressed when Germany invaded France on 10 May 1940, and in late May it was decided to evacuate the near complete prototypes from Villacoublay near Paris, with the first prototype being sent to Bône in Algeria and the second to the Breguet factory at Anglet, near Bayonne in the far south-west of France. The first prototype was destroyed during a German air-raid in November 1942 following the Allied invasion of French North Africa, but the first prototype remained hangered untouched, despite the fact that Anglet had been occupied by the Germans since 1940.
When the Germans withdrew, Breguet resumed work on the Br 482, proposing to complete it with more powerful Hispano-Suiza 12Z engines and a heavier armament. The French Armée de l’Air had no requirement for a bomber, however, and it was decided to use the aircraft, with the planned modifications, but with armament removed, as a research aircraft. Breguet deleted one of the crew positions leaving the Br-482 a three-man plane. The defensive guns, which had not been fitted before France’s 1940 surrender, were never installed and the mounts deleted. The engines were upgraded to the newest and most powerful model of the Hispano-Suiza 12Z with a centrifugal supercharger.
In this form it was finally flown for the first time on 27 November 1947 with a crew of three, being used for various experimental purposes, including testing of the 12Z engines.
The Br-482’s first mission was to explore the performance regime of the supercharged upgraded engines. They did not perform as well as expected and the Br-482 was never able to explore the full range of its flight envelope. After frequent engine failures the Br-482 was restricted to 84% throttle. Although Spain and Yugoslavia used the supercharged 12Z engine after WWII, the lone Br-482 was the only French plane to use it.
After these tests, it had been planned to use the Br-482 to test the planned 24Z engine and a new contra-rotating propeller design. Both of these projects were cancelled. Likewise, a planned quad gun mount design was cancelled before tests aboard the Br-482 could start.
In 1949, some consideration was given to re-engining the Br-482 with Gnome-Rhone 14R radial piston engines. The last design of Gnome-Rhone (which did not survive the occupation), the 14R was built by SNECMA after WWII and were 15% more powerful than the 12Z. There were concerns about the stability of the Br-482 at the increased speed, especially with the weight of the guns, bombsight, and fourth crewman missing. The re-engining was never done. The plane continued in use with the original engines as an observation vehicle for early French ballistic missile tests.
Twenty flights in all were done between 1948 and 1950. At some point in 1950, the Br-482 was transferred out of the French air force’s inventory and given the civil registration F-WFRM.
The Br-482 was discarded on 13 September 1950. The deactivated plane, stripped of the engines and equipment, was still in existence as late as 1952 when it was presumably finally scrapped.
Br 482
Engines: 4 × Hispano-Suiza 12Z, 1,007 kW (1,350 hp) (take off power)
Wingspan: 24.09 m (79 ft 0 in)
Wing area: 64.4 m2 (693 sq ft)
Length: 18.86 m (61 ft 11 in)
Height: 5.21 m (17 ft 1 in)
Empty weight: 10,450 kg (23,038 lb)
Gross weight: 14,500 kg (31,967 lb)
Maximum speed: 560 km/h (348 mph; 302 kn) at 8,000 m (26,250 ft)
Cruising speed: 529 km/h (329 mph; 286 kn)
Range: 1,519 km (944 mi; 820 nmi)
Service ceiling: 12,000 m (39,370 ft)
Crew: 3
Armament: 1 x Hispano-Suiza HS.404 20mm gun firing forward (500 rds), twin Reibel 7.5mm machine gun in the dorsal position (600 rds), two loose MAC-1934 7.5mm machine guns firing from drop-down belly mounts.
Bombload: 5,500 lbs / 2500 kg
Br.482B.4
Engines: 4 x Hispano-Suiza 12 Y 51, 1100 hp
Wingspan: 24.20 m
Wing area: 67.90 sq.m
Length: 18.60 m
Height: 4.25 m
Empty weight: 9500 kg
Normal takeoff weight: 16,060 kg
Cruising speed: 400 kph
Practical range: 2500 km
Practical ceiling: 9000 m
Crew: 4
Armament: one 20-mm cannon Hispano-Suiza / four 7.5-mm machine gun Darne
Bombload: 2500 kg
