SNCASO SO.6020 Espadon

Designed to meet a 1946 French requirement for a jet powered fighter-interceptor, the SNCASO SO.6020 Espadon first flew on 12 November 1948. Three prototypes were ordered, with the potential for an order of 230 aircraft if testing was successful.

The first prototype (SO.6020.01) had a ventral air intake that not only proved inefficient which restricted the output power, but also collected debris from the runway. Following an engine failure and subsequent forced landing, it was repaired and continued flight testing. It was later fitted with experimental wing tip turbojets.

With lessons learned from the first unarmed prototype, the second prototype designated SO.6020.02 had revised air intakes on either side of the fuselage. This arrangement did little to improve the airflow to the engine. Armament of this aircraft was six nose-mounted 20mm cannon.

Testing of the first two prototypes demonstrated poor handling and maneuverability.

The third prototype was converted to the SO.6025 while under construction to explore a mix-powered fighter. The air intake reverted to that of the first prototype and the rear section of the intake fairing was extended to house a 14.7-kilonewton SEPR 25 liquid-fuel rocket engine.

The proposed production variant the SO.6021 incorporated weight savings and enlarged wings and modified vertical stabilizer. Performance was still unacceptable and the French Air Force cancelled the project, using the remaining prototypes for experimental work on mixed engined fighters (the SO.9000).

The second prototype was modified to support the SO.9000 project with a rocket engine installed in the tail similar to the SO.6025 but with a neater installation.