In 1939 the U.S. Army Air Corps put out a request for something deliberately radical — a fighter that broke the rules of how a fighter should be built. Vultee's answer was the XP-54: a twin-boom machine with an inverted gull wing, the engine and propeller mounted at the back, and a cockpit the pilot entered by riding his own seat up into it like a lift. It looked like the future. It flew like a disappointment.

Only two were ever built, and the second flew exactly once. This is the story of the Swoose Goose — one of the most ambitious, over-engineered fighters America never fielded.

The competition for the unconventional

The R-40C proposal invited manufacturers to abandon convention entirely, and three unusual pusher designs emerged from it: Vultee's XP-54, the Curtiss XP-55 Ascender, and the Northrop XP-56 Black Bullet. None would reach production. Vultee's design, internally the Model 84, won the competition, and a prototype contract was signed on 8 January 1941, with a second aircraft ordered in March 1942.

An engineer's fever dream

The detail engineering was extraordinary. The 12-foot pusher propeller sat between the twin booms, behind the pilot — which made a conventional bail-out lethal, so the ejection system fired the pilot and seat downward, clear of the blades. To board, the pilot lowered that same seat electrically to the ground, sat down, and rode it up into the pressurised cockpit. The inverted gull wing incorporated a NACA-developed "ducted" section to house radiators and intercoolers.

Strangest of all was the nose. The entire nose section could pivot — three degrees up and six degrees down — so that the two 37 mm cannon could be elevated to aim without changing the aircraft's attitude, coordinated by a special compensating gunsight. It was clever, complicated, and heavy.

Betrayed by its engine

Every ambitious airframe needs an engine to match, and here the XP-54's fate was sealed. Its intended powerplant, the Pratt & Whitney X-1800, was cancelled mid-programme. Vultee substituted the liquid-cooled Lycoming XH-2470 — which never delivered the promised power. Worse, in September 1941 the aircraft's role was switched from low-altitude to high-altitude interception, adding a turbo-supercharger and heavier armour and pushing the empty weight to around 18,000 pounds. A heavy airframe on an underpowered engine is a slow airframe.

Two aircraft, one dead end

Vultee test pilot Frank Davis took the first XP-54 into the air on 15 January 1943. The performance simply was not there — well short of what had been promised. The second prototype made a single flight and no more. With the engine problems unresolved and the whole R-40C pusher experiment yielding nothing usable, the project was cancelled.

The Swoose Goose is remembered now exactly as it deserves to be: a beautiful, brilliant, hopelessly over-complicated answer to a question the jet age was about to make irrelevant. Within a few years, the propeller-at-the-back fighter was a historical curiosity — and the XP-54 was its most elegant tombstone.

Sources: U.S. Air Force Test Center; The Aviation History Online Museum; MilitaryFactory; Rex's Hangar.