4 Most Peculiar Allied Prototype Planes You’ve Never Heard of from WWII

During the Second World War, aircraft design changed at a speed never seen before. Engineers on every side searched for new ways to gain an advantage in the sky, and the Allied nations were no exception. Several experimental planes were built that did not follow the normal patterns of the time. While few of them reached combat, they reveal how far designers were willing to go in the search for better performance.

High-Altitude Wellington

Britain’s Vickers Wellington bomber began the war as a key part of the Royal Air Force. Strong and adaptable, it inspired a special high-altitude version intended to fly well above enemy fighters and anti-aircraft fire. This Mark VI model included a pressurized cabin and a redesigned nose with a small dome for the pilot and a forward observation space for the navigator. Early versions used Bristol Hercules engines that struggled in thin air, so engineers switched to Rolls-Royce Merlin engines, the same type used in the Spitfire. Even with these improvements, bombing from extreme heights proved too inaccurate, and only a small number were built. They served mainly in testing and training before the project ended in 1943.

Mid-Engine Fighters

Seeking fighters that could climb fast and hit hard, designers in the United States placed engines behind the pilot to free space in the nose for heavier weapons. The Bell P-39 Airacobra carried a 37 millimeter cannon and had a clean, narrow nose that cut through the air. It struggled at high altitudes over Western Europe but performed well at the lower levels common on the Eastern Front, where Soviet pilots valued its ruggedness and firepower. Bell tried a naval version and later produced the improved P-63 Kingcobra, while other American firms explored similar ideas. The Fisher P-75 Eagle combined parts from several existing planes but failed to outperform the dependable P-51 Mustang and was cancelled.

The Tailless Handley Page Manx

Britain also tested radical shapes. The Handley Page Manx had no true tail and carried two pusher engines mounted on swept wings. Its crew sat in a heavily glazed pod that offered wide views. Built mostly of wood, the lone prototype faced long delays and only made a handful of short flights between 1943 and 1946 before being scrapped. Despite limited results, it gave engineers valuable experience with tailless flight.

American Proposal R-40C

In 1939 the U.S. Army Air Corps invited designers to create a fighter with great visibility and heavy weapons, even if the design was unconventional. Three prototypes emerged. The Vultee XP-54 placed its propeller at the rear and allowed its machine guns to move for better aim. The Curtiss-Wright XP-55 featured swept wings and an escape system to avoid its spinning propeller. The Northrop XP-56 used a compact body with minimal fuselage and reached high speeds but suffered stability problems. None entered production, yet the research helped later jet projects.