In the mid-1950s, a needle-thin French aircraft with jet engines perched on its wingtips and a rocket motor in its belly clawed its way toward the edge of space, touching nearly twice the speed of sound and setting records for how fast a jet could climb. And then France did something strange: it told almost no one.

The SNCASO Trident was one of the boldest and least-known interceptors of the Cold War — a machine that mixed rocket and jet power to reach heights and speeds that embarrassed aircraft twice its size. It should have been a national triumph. Instead, its finest achievements were quietly buried so as not to embarrass the aircraft the French Air Force had already chosen: the Dassault Mirage.

Its story is one of dazzling performance, a terrifying fuel, and a death that helped seal its fate.

France’s postwar comeback

The Trident was born of ambition and anxiety. French aviation had been strangled under occupation, and after the war the country was desperate both to revive its aircraft industry and to defend its cities against a new threat: high-flying Soviet bombers carrying nuclear weapons. What was needed was an interceptor that could be scrambled and rocket to altitude in a matter of minutes. Impressed by Germany’s wartime Me 163 rocket fighter but wary of relying on rocket power alone, the French Air Force asked for a hybrid — part rocket, part jet.

A rocket in the belly, jets on the wingtips

SNCASO’s answer was as elegant as it was unusual. The fuselage was long, slim and streamlined around a single seat set low in the airframe. A SEPR rocket motor sat inside the fuselage to hurl the aircraft skyward, while two small turbojets were bolted to the wingtips for ordinary flight. The rocket burned a mixture of Furaline and nitric acid — propellants chosen partly because they needed no separate ignition, but which were unforgiving to handle.

Blisteringly fast — and dangerous to fly

On 2 March 1953, test pilot Jacques Guignard took the first Trident aloft, using the entire runway to get airborne on the weak wingtip jets alone. Once the rocket was lit, though, the little aircraft transformed, eventually pushing toward Mach 2. But the volatile fuel that gave it such performance also made it lethal. On 21 May 1957, while rehearsing for a display at the Paris Air Show, a Trident exploded in mid-air; investigators concluded the Furaline and nitric acid had mixed and detonated, killing test pilot Charles Goujon.

The records nobody was allowed to hear about

Even after that tragedy, the improved Trident II kept astonishing everyone who saw it fly. It reached close to Mach 2 and, in 1958, set a record for the fastest climb ever recorded by a jet aircraft, rocketing toward altitudes few contemporaries could touch. It was exactly the kind of achievement a nation trumpets to the world. France did the opposite — because by then the Air Force had already committed to the Dassault Mirage III, and loud praise for a rival design would only have caused embarrassment.

Beaten by the Mirage

The French Air Force briefly ordered a handful of production Tridents, then cancelled them amid budget cuts. A record-breaking demonstration flight was flown to win back official enthusiasm, but the effort came to nothing.

The Mirage was simpler, cheaper and easier to maintain, and it would go on to become one of the most successful fighters in history. The Trident, for all its brilliance, was dismantled for spares, and a single surviving example was sent to a museum. It remains one of the fastest, wildest interceptors of its age — and one that most of the world never even knew existed.

Sources: PlaneHistoria (Guy Davey); Wikipedia (SNCASO Trident); Military Factory. Speed and altitude figures vary between sources and are given as reported.