Vultee XP - 54 The Vultee XP - 54 " Swoose Goose " was a prototype fighter built by the Vultee Aircraft Company for the United States Army Air Forces ( USAAF ) . Design and development . Vultee had submitted a proposal in response to a U . S . Army Air Corps request for an unusual configuration . The Vultee design won the competition , beating the Curtiss XP - 55 Ascender and the Northrop XP - 56 Black Bullet . Vultee designated it Model 84 , a descendant of their earlier Model 78 . After completing preliminary engineering and wind tunnel tests , a contract for a prototype was awarded on 8 January 1941 . A second prototype was ordered on 17 March 1942 . Although it appeared to be a radical design , its actual performance was lackluster and the project was subsequently canceled . The XP - 54 was designed with a pusher engine in the aft part of the fuselage . The tail was mounted rearward between two mid - wing booms , with the 12 - ft propeller between them . The design included a " ducted wing section " developed by the NACA that enabled installation of cooling radiators and intercooler s in the inverted gull wing . The Pratt & Whitney X - 1800 engine was initially proposed as the powerplant but after its development was discontinued , the liquid - cooled Lycoming XH - 2470 was substituted . In September 1941 , the XP - 54 mission was changed from low altitude to high altitude interception . Consequently , a turbo - supercharger and heavier armor had to be added , and the estimated empty weight increased from 11 , 500 to 18 , 000 lb ( 5 , 200 to 8 , 200 kg ) . The XP - 54 was unique in numerous ways . The pressurized cockpit required a complex entry system : the pilot ’ s seat acted as an elevator for cockpit access from the ground . The pilot lowered the seat electrically , sat in it , and raised it into the cockpit . Bail - out procedure was complicated by the pressurization system and necessitated a downward ejection of the pilot and seat in order to clear the propeller arc . Also , the nose section could pivot through the vertical , three degrees up and six degrees down . In the nose , two 37 mm T - 9 cannon were in rigid mounts while two . 50 cal machine guns were in movable mounts . Movement of the nose and machine guns was controlled by a special compensating gun sight . Thus , the cannon trajectory could be elevated without altering the flight attitude of the airplane . The large nose section gave rise to its whimsical nickname , the Swoose Goose , inspired by a song about Alexander who was half swan and half goose : " Alexander was a swoose . " Operational history . Flight tests of the first prototype , " 41 - 1210 " , began on 15 January 1943 . Initial trials showed performance substantially below guarantees . At the same time , development of the XH - 2470 engine was discontinued and , although it appeared possible to substitute the Allison V - 3420 engine without substantial airframe changes , the projected delay and costs resulted in a decision not to consider production buys . The prototypes continued to be used in an experimental program until problems with the Lycoming engines and lack of spare parts caused termination . The second prototype , " 42 - 108994 " ( but mistakenly painted as " 42 - 1211 " ) equipped with an experimental GE supercharger , only made one flight before it was relegated to a " parts plane " in order to keep the first prototype in the air .