Sud-Ouest Espadon
SO.6020 Espadon | |
---|---|
The SO.6021 before it was modified as an engine testbed in 1951 | |
Role | Prototype interceptor |
National origin | France |
Manufacturer | SNCASO |
First flight | 12 November 1948 |
Number built | 4 |
The Sud-Ouest SO.6020 Espadon (Swordfish) was a French post-war
Background and description
Designer Lucien Servanty and his team at SNCASO began work on jet-powered fighters in 1945 and submitted a design proposal that the company designated as the SO.6020 when the French Air Force issued a specification for a single-seat assault fighter-interceptor on 25 March 1946. The aircraft had to have a speed in excess of 900 kilometers per hour (559 mph) at an altitude of 10,000 meters (32,808 ft), an endurance of one hour with 15 minutes in combat, a take-off distance less than 1,200 meters (3,937 ft), a cockpit armored against 12.7-millimeter (0.5 in) shells, and an armament of six 20-millimeter (0.8 in) or four 30-millimeter (1.2 in) autocannon. The Air Force ordered three prototypes on 28 June, with plans to order more than 230 interceptors if the aircraft satisfied its requirements.[1]
As built, the aircraft was a metal-skinned mid-wing
Development
The unarmed first prototype made its maiden flight on 12 November 1948, delayed by the late delivery of its radio equipment. This aircraft had a ventral air intake for the engine that proved to be very inefficient and tended to collect objects from the runway. This caused the prototype to be very underpowered and it failed to meet nearly all of the specifications. It had an engine failure in flight on 1 December 1949 that caused a belly landing, but it was repaired and returned to flight testing. It was later modified for flying trials with small wingtip-mounted turbojets.[3]
The second prototype was scheduled to make its first flight on 15 August 1948, but this was delayed until 16 September 1949, possibly due to the need to revise the air intake to improve the flow to the engine. SNCASO decided upon a pair of protruding intakes on the sides of the fuselage under the trailing edge of the
The third prototype was intended to serve as an unarmed
The proposed production variant, the SO.6021, was lightened in the hopes of improving its performance by reducing the amount of armor plate carried and shrinking the canopy. It was fitted with an enlarged wing and a new vertical stabilizer and weighed about 400 kilograms (880 lb) less than the first SO.6020 prototype. The aircraft made its maiden flight on 3 September 1950. It could reach Mach 0.96 in a dive, but encountered serious
The second prototype was subsequently converted into the SO.6026 with a SEPR 25 rocket below the tail pipe, also to support the SO.9000 program. It first flew with the rocket installed on 15 October 1951, but the first rocket-powered flight did not occur until 26 March 1953. It demonstrated its rocket's ability to climb at the 1953 Paris Air Show, but only made a total of 28 flights before it was placed in storage in early 1955, of which only 13 used its rocket.[10][5]
Variants
- SO.6020-01
- Nene-powered prototype, later fitted with two small wingtip-mounted turbojets.[3]
- SO.6020-02
- Second prototype, later modified with the addition of a SEPR 25 rocket engine and re-designated SO.6026.[5]
- SO.6020-03
- Third prototype, modified while under construction as the SO.6025 also with a SEPR 25 rocket.[7]
- SO.6021
- The proposed production aircraft with a variety of structural changes to reduce weight and improve performance. Unsuccessful and it too was later used to test wingtip turbojets.[11]
- SO.6025
- The third prototype fitted with a SEPR 25 beneath the fuselage.[12]
- SO.6026
- The second prototype was also modified with a SEPR 25 in a neater installation in the tail.[13]
Surviving aircraft
- The sole SO.6025 is at the Ailes Anciennes Toulouse Museum in poor condition.[14]
Specifications (SO.6021)
Data from The Complete Book of Fighters;[15] X-Planes of Europe II: Military Prototype Aircraft from the Golden Age 1946–1974[16]
General characteristics
- Crew: 1
- Length: 15 m (49 ft 3 in)
- Wingspan: 10.6 m (34 ft 9 in)
- Height: 4.72 m (15 ft 6 in)
- Wing area: 26.5 m2 (285 sq ft)
- Empty weight: 4,750 kg (10,472 lb)
- Gross weight: 6,870 kg (15,146 lb)
- Powerplant: 1 × Rolls-Royce Nene centrifugal turbojet engine, 22.2 kN (5,000 lbf) thrust
Performance
- Maximum speed: 860 km/h (530 mph, 460 kn) at sea level
- Maximum speed: Mach 0.96
- Endurance: 2.5 hours
- Service ceiling: 13,000 m (43,000 ft)
- Rate of climb: 27 m/s (5,300 ft/min)
- Time to altitude: 8 minutes, 20 seconds to 10,000 m (33,000 ft)
Armament
- Guns: 6 × 20 mm (0.8 in) autocannon
References
Notes
- ^ Carbonel 2016, p. 51
- ^ Buttler 2015, pp. 45, 52
- ^ a b Carbonel 2016, pp. 52–53
- ^ Buttler 2015, pp. 46–48
- ^ a b c Carbonel 2016, pp. 54, 65
- ^ Buttler 2015, pp. 49–51
- ^ a b Carbonel 2016, pp. 54, 63–64
- ^ Buttler 2015, p. 49
- ^ Carbonel 2016, p. 55
- ^ Buttler 2015, p. 51
- ^ Carbonel 2016, pp. 55, 63–64
- ^ Carbonel 2016, pp. 63–64
- ^ Carbonel 2016, p. 65
- ^ Buttler 2015, p. 281
- ^ Green & Swanborough 1997, p. 548
- ^ Buttler 2015, p. 44
Bibliography
- Buttler, Tony (2015). X-Planes of Europe. Vol. II: Military Prototype Aircraft from the Golden Age 1946–1974. Manchester, UK: Hikoki Publications. ISBN 978-1-902109-48-0.
- Carbonel, Jean-Christophe (2016). French Secret Projects. Vol. 1: Post War Fighters. Manchester, UK: Crecy Publishing. ISBN 978-1-91080-900-6.
- Green, William & Swanborough, Gordon (1997). The Complete Book of Fighters. London: Salamander Books. ISBN 1-85833-777-1.