In November 1947 the French naval air arm wrote a specification for a carrier aircraft that could do two things. It had to loiter for four hours at low level hunting submarines, and it had to be able to dash at 700 km/h.

Those are not two requirements. They are two aeroplanes.

Bréguet’s response was to build both of them into one airframe. The Br.960 Vultur had an Armstrong Siddeley Mamba turboprop in the nose, driving a propeller, and a Rolls-Royce Nene turbojet in the tail, breathing through ducts in the wing roots. Two built. Neither entered service. And yet the second one ended up flying, in a manner of speaking, until the year 2000.

A Specification That Argued With Itself

The Aéronavale wanted an aircraft that could carry bombs, depth charges, guided missiles, rockets and torpedoes, take off with rocket assistance, stay airborne for four hours at sea level, reach anything between 300 and 700 km/h, land at under 155 km/h, and carry armour for the crew.

Bréguet looked at that list and concluded, correctly, that no single powerplant available in 1947 could deliver both ends of the speed range. A turboprop is efficient at low speed and runs out of usefulness as it goes faster. A turbojet of the period was thirsty at low level and hopeless at loitering. Pick one and you fail half the specification.

So Bréguet picked both.

The Shape of the Compromise

The Vultur was a low-wing monoplane with an oval monocoque fuselage and tricycle landing gear. Its two-spar wing had a swept leading edge and a straight trailing edge, and folded vertically on hydraulics for carrier stowage. The tailplane was swept too, with 16 degrees of dihedral. The pilot and copilot sat side by side under a framed canopy.

Fuel went into a 600-litre self-sealing tank in the fuselage and a 350-litre self-sealing tank in each outer wing panel. A single hardpoint under the fuselage could carry 1,000 kg, or a container holding a more powerful search radar. Four underwing launchers took two rockets each.

The first prototype flew on 4 August 1951 with a 970 shp Mamba I and a Nene 101 of 21.6 kN. It was badly underpowered. It could not be flown at full load at all unless the jet was running, which rather undermined the point of having a fuel-efficient turboprop in the nose.

The Second One Worked

The second prototype flew on 15 September 1952 with a 1,320 shp Mamba III and a 22.2 kN Nene. It carried small nacelles on the wingtips: fuel to port, an attack radar to starboard.

It met every requirement of the specification. And here the story produces one of those details that says more about post-war European aviation than any amount of analysis.

France was designing a carrier-borne strike aircraft and had to send it to England to find out whether a catapult would break it.

Both prototypes shared one genuinely alarming trait: neither gave any warning of an approaching stall. On a carrier aircraft, whose entire working life is spent flying slowly towards a moving deck, that is not a footnote.

The Br.960 Vultur and the reasoning behind its mixed powerplant.

The Navy Changed Its Mind

In 1953 and 1954 the Aéronavale went off the whole idea of a turboprop attack aircraft. What it now wanted was a dedicated submarine hunter. The Vultur, built to satisfy a contradiction, had watched the contradiction dissolve.

The first prototype was modified as the Br.963 to test engine air blown through slots in the upper wing surface, an early attempt at blown-flap lift augmentation.

The second prototype was rebuilt into something else entirely. The Nene came out and its tailpipe was blanked off. The turboprop was upgraded to a Mamba VI. A retractable AN/APS-15 search radar went into the fuselage, the wingtip nacelles came off, extra fuel replaced the now-redundant engine air ducts, and the landing gear was reworked to retract forward into nacelles on the wing leading edges.

Renamed the Br.965 Épaulard, or Killer Whale, it first flew on 26 March 1956. It had a landing accident on 2 May and was reduced to a source of spares for the first prototype. Five weeks of flying.

Forty-Four Years Later

Those five weeks mattered. The Épaulard was the immediate forerunner of the Bréguet Br.1050 Alizé, which first flew on 6 October 1956 and went on to have one of the longest and least celebrated careers of any Cold War naval aircraft.

Eighty-nine were built between 1957 and 1962. Seventy-five went to the Aéronavale, flying from the carriers Arromanches, Clémenceau and Foch. Twelve went to the Indian Navy, which operated them from shore bases and from the light carrier INS Vikrant.

Indian Alizés flew reconnaissance during the 1961 annexation of Goa, maritime patrol and electronic intelligence in the 1965 war, and anti-submarine patrols in 1971. During that last conflict an Alizé was shot down by a Pakistan Air Force Caccia stellare F-104. The type also sank three gunboats and flew some 300 sorties, being the only night-capable aircraft aboard Vikrant.

The Indian Navy retired its Alizés in 1991. One is preserved at the Naval Aviation Museum in Goa. In France a single airworthy example survives and still appears at airshows.

A French Navy Alizé operating from the carrier Foch in 1968.

The sole airworthy Bréguet 1050 Alizé displaying at Duxford.

What the Vultur Was For

Judged as a product, the Br.960 was a failure. Two aircraft, no orders, a layout nobody repeated.

Judged as an argument, it was correct. Bréguet was asked for something impossible and, rather than pretending otherwise, built an aeroplane that demonstrated exactly why it was impossible, and in the process worked out the wing, the fuselage, the folding mechanism, the radar installation and the deck handling for the aircraft that actually mattered.

The Alizé flew for forty-four years. It could not have done so without a vulture that carried a propeller and a jet pipe and never quite decided which one it was.

Sources: Wikipedia entries on the Bréguet Vultur and the Bréguet Alizé, drawing on the Aéronavale specification of 12 November 1947 and published Bréguet prototype records; Indian Navy operational histories of the Alizé