Kawasaki Ki-61, the only Japanese WWII fighter to use an in line engine. Westerners often claimed that it was Japanese copy of the German Me-109 Messerschmitt, which it was not. It was probably more agile than the Messerschmitt. During the last days of the war, the Japanese had many partly completed airframes, but were short of engines. The installed radial engines instead, a brilliant piece of engineering. The resulting aircraft was better than the Ki-61. It was named the Ki-100.
@@fredferd965 I was just kidding but thank you very much for your reply and this sense of dignity and respect that you convey with your words to those pilots on both sides! Arigatou gozaimashita!