Reddit mentions of Herman the German: Enemy Alien U.S. Army Master Sergeant #10500000

I know the Zero was designed to make it very quick to change engines. Herman the German:

"Japanese design philosophy was far advanced, intelligent and interesting. Like today's automobiles imported from the Land of the Rising Sun, the Zero included many creative innovations. Its oil cooler, oil tank, American-type propeller and engine were assembled into one single unit held with only four big nuts to the plane's firewall (the front of a fuselage). All fuel, oil, pressure, temperature and other service lines were connected into a single, simple, "quick-disconnect" junction box. To install or remove a complete Japanese power plant together with its propeller and oil cooler system took twenty-five to thirty minutes, while a similar job on its American counterpart, the Curtiss P-40 or newer North American P-51, needed five to eight hours! Such dramatic time advantage meant very much in a combat area, where an extra plane in the air could mean a victory while one left on the ground could become
a loss due to strafing or bombing by the enemy. The Zero's right and left wings were one integral assembly with the cockpit, to save the weight of flanges and bolts. Its landing gear was light, weighing one-third of a P-40's. Other components of the Zero such as the gunsight or oxygen system were similar to or copies of German and
Russian designs."