Hien

The Kawasaki Ki-61 Hien (Flying Swallow) was a Japanese World War II fighter aircraft used by the Imperial Japanese Army Air Force. It was superior to the Zero and was the only mass-produced Japanese fighter of the war to use a liquid-cooled inline "V" engine. Because of it's unusual appearance for a Japanese fighter, the Allies code name for the plane was "Tony," because of it's likeness to Italian fighters.

Hien in Days of Infamy
Lt. Saburo Shindo complained about the Hien's high maintenance costs and lack of skilled mechanics. Most of all, he complained that there weren't enough to go around, while the United States was mass producing the Hellcat at an alarming rate.