Experimental Fighter Planes During World War II

I’ve always been interested in history from all eras. War is awful but war often leads to fast technological advances. Here are some experimental U.S. fighter planes that were built during World war II (1940 – 1945). None of these planes went into production because they weren’t significantly better than designs already in production. By 1945, all design efforts had been focused on jet aircraft — but that’s another blog post.

I think we’re in the very early stage of deep learning. Perhaps the development of quantum computing will be the jet engine of deep learning.


Shown below are six of the U.S. land-based fighter planes that were already in production. The “P” stands for “pursuit” (fighter) and “XP” stands for “experimental pursuit”.

Top row. Left: Lockheed P-38 Lightning. Center: Bell P-39 Airacobra. Right: Curtiss P-40 Warhawk.

Bottom row. Left: Republic P-47 Thunderbolt. Center: North American P-51 Mustang. Right: Vought F4U Corsair (originally intended for aircraft carrier use, switched to land-based).


1. Curtiss XP-46 (1941) – Intended to be a successor to the existing P-40 plane, but it’s performance wasn’t better than the P-40D model.


2. Grumman XP-50 (1941) – Not ordered for production but the design evolved into the successful F7F Tigercat.


3. Bell XP-52 (1941) – Advanced design that would have featured contra-rotating pusher and swept wings. Canceled because of other higher priority designs, including the P-59 Airacomet jet plane. (The XP-52 is the only plane listed that didn’t have at least one prototype built, but it looked too cool to leave out.)


4. Vultee XP-54 (1943) – Did not exceed the performance of existing production aircraft.


5. Curtiss XP-55 (1943) – It’s performance did not meet expectations.


6. Northrop XP-56 (1943) – Proved to be an unstable design.


7. Curtiss XP-60 (1941) – Intended to be a successor to the existing P-40. Development not pursued because of other war-time production priorities.


8. Curtiss XP-62 (1943) – Had good performance but development was not pursued because of other, higher priority efforts.


9. McDonnell XP-67 (1944) – Very unusual design but only had performance equivalent to existing aircraft already in production.


10. Republic XP-72 (1944) – Had excellent performance but attention had turned to the first jet-powered aircraft.


11. Fisher XP-75 (1943) – Twin contra-rotating propellers. Performed well but not significantly better than existing P-51 already in production.


12. Bell XP-77 (1944) – Explored the idea of a very small, very lightweight design. Ultimately, large, heavy designs proved to be much better.


13. Vultee XP-81 (1945) – Combined two small jets with a regular engine. Excellent performance but by the time it first flew, it was clear that fully jet-powered planes were the future.


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