Sud-Ouest SO 4000
The SO 4000 was developed by the Société Nationale de Constructions Aéronautiques de Sud-Ouest (SNCASO) to meet an Armée de l’Air requirement formulated shortly after WWII for a twin-turbojet bomber capable of high subsonic speeds and having a maximum loaded weight of 25-30 tonnes. The SO 4000 project competed with the NC 270 project tendered by the SNCA du Centre, and after the flight testing of manned scale models, the SNCASO bomber was selected for further development. The half-scale model predecessors of the SO 4000 were the SO M.1 glider (F-WFDJ) and the powered SO M.2 (F-WFDK).
The single prototype of the full-scale SO 4000 bomber, (F-WBBL) had been rolled out for the first time on 5 March 1950. While essentially similar in configuration to the M.1 and M.2, the SO 4000 featured a tall undercarriage comprising a single nosewheel and tandem mainwheels each with independent legs. This undercarriage proved some-what fragile, collapsing during ground trials on 23 April. After repairs were completed, flight testing finally commenced at Orleans-Bricy on 15 March 1951, test pilot Daniel Rastel being accompanied by flight engineer Pistrak.
The SO 4000 was powered by two Rolls-Royce turbojets mounted side-by-side in the rear fuselage, these being fed via lateral intakes immediately aft of the pressurised forward fuselage. Fuel was accommodated above the weapons bay in the centre fuselage and proposed defensive armament consisted of remotely-controlled gun barbettes at the wingtips. The 31 deg swept wing had a 10 per cent thickness/chord ratio from root to tip and the control arrangement was fundamentally similar to that of the M.2. The initial flight of the SO 4000 was also to prove its last as the undercarriage collapsed once more on alighting, the programme subsequently being discontinued as a result of a reduction in military credits.
Engines: 2 x Rolls-Royce Nene 102 turbojets, 4,980 lb st (2 260 kgp)
Fuel cap: 1430 ImpGal (6500 lt)
Wing span: 58 ft 7 1/8 in (17,86 m)
Length: 64 ft 9½ in (19,75 m)
Wing area of 807.32 sq ft (75,00 sq.m)
Empty wt: 36,5581b(16 583 kg)
Loaded wt: 48,510 lb(22 005kg)
Estimated performance - Max speed of 528 mph (850 km/h) at 29,530 ft (9 000 m) or Mach 0.78 and 515 mph (830 km/h) at sea level or Mach 0.675.