French aero-industry has always been at the forefront of aviation, proven through war-winning designs in World War 1 (1914-1918) and revolutionary entries seen during the interwar years leading up to World War 2 (1939-1945). While derailed by the German invasion - and subsequent victory - of 1940, the industry continued to develop albeit at a limited pace. After the war, the monumental rebuilding effort of the war ravaged nation included revitalization of the aviation sector which went on to produce some very successful combat platforms utilized globally throughout the Cold War period. The pinnacle of French fighter design later became the exceptional Dassault "Rafale" multi-role fighter.
Back in the 1950s, amidst a backdrop that included a very real threat from an invading Soviet Union in Europe, the French joined other leading aviation powers in delving into the world of Vertical Take-Off and Landing (VTOL) aircraft, mainly due to the growing efficiency, power, and reliability of turbojet technology. The concept behind the technology was related to fast-reacting interceptors not requiring the use of traditional airfield runs or associated facilities. Instead, these "tail-sitting" fighters remained at-the-ready, responding to inbound threats in short order.
For the French, the result of the work during this period became the SNECMA C.450 "Coleoptere" - a prototype VTOL air vehicle of which only one was ever completed and tested.
The Coleoptere was preceded by the SNECMA C.400 "Volant" which was essentially a series of test beds. The "aircraft" were of largely cylindrical form housing the turbojet with the pilot's cockpit added to the tip. The design sat on its "tail" with four castor-wheeled legs allowing for limited ground-running and support. The entire arrangement was quite utilitarian in appearance but, for the purposes of research, it fit the bill for its time.
Based in the wartime German BMW 003 turbojet, the SNECMA "Atar" engine in play was a dimensionally larger, and subsequently more powerful, version of the enemy design. Indeed, the name "Atar" was derived from the German facility at Reichenbach - "ATelier Aeronatiques de Reichenbach". Like the Americans and Soviets, the French also benefitted from former German aeronautical engineers coming to work for them in the post-war world.
Appearing like something out of a 1950s Science Fiction magazine, the Coleoptere certainly had a unique appearance about it: the fuselage emerged from an oversized cylindrical shroud that housed the turbojet engine. As in the C.400, the C.450 fitted four wheeled landing gear legs at its extreme rear and emanating from the smallish triangular vertical tailfins. The cylinder - known technically as an "annular wing" (essentially an unbroken, wrap-around surface) - was smooth all around its run with the fuselage jutting out from the barrel shape to form the forward section containing the single-seat cockpit. The pilot sat in an ejection seat designed to tilt in relation to the aircraft's horizontal axis - the crewman seated traditionally when the aircraft was at rest (due to the tail-sitting nature of the design) and facing the nose when in horizontal flight. It was intended that, as a VTOL aircraft, the C.450 would take-off and land vertically while general flight would be accomplished in a traditional, forward-moving way - all relying on the single Atar turbojet engine.
While the Atar EV (101E) axial-flow turbojet engine came from SNECMA, the whole of the airframe form was constructed by the specialists of Nord Aviation. The engine provided up to 8,200lb of thrust. Structural dimensions included a length of 26.3 feet and a span of 14.9 feet. Diameter of the aircraft reached 10.5 feet. Aspiration for the air-breathing turbojet was via a pair of intakes found alongside the forward fuselage near the cockpit.
Work on the Volant technology demonstrators was begun in 1956 and the C.450 Coleoptere achieved powered lift-off in 1958 followed by a true first-flight on May 6th, 1959. Eight flights involving the C.450 were accomplished by test pilot Aguste Morel - with inherent deficiencies in the design approach soon showing through (namely in control/handling). During testing, the aircraft achieved a recorded altitude of just 2,625 feet and it was during the ninth flight, intended to transition to a pseudo-horizontal flight phase, that the aircraft became uncontrollable - the test pilot electing to eject (safely though injured) at 492 feet. This resulted in the destruction of the only airframe completed for the project. A proposed second flying airframe never materialized.