Science: What Adds Up to a Zero

The quick-zooming, vulnerable Jap Zero* fighter is a triumph for the world’s greatest adapters. How the underestimated little single-motored plane could get away with such power and maneuverability was a mystery for several weeks after Pearl Harbor. U.S. aviators soon found part of the answer (and made the most of it): no armor protection for pilot or self-sealing fuel tanks, therefore less weight. The rest of the story has come out gradually from examination of shot-down Zeros.

In the pre-war days the Japs had plenty of opportunity to pick up plane pointers from sales-minded U.S. and European manufacturers. They bought one, two, or a few of each type that looked good, and immediately set about copying them. United Aircraft’s Pratt & Whitney and Curtiss-Wright’s Wright Aeronautical Corp. licensed Japanese manufacturers to make certain types of their motors. Hamilton Standard (propellers) sold their plans outright. Douglas Aircraft sold them the original DC-4.

The Japs juggled parts and built experimental planes that would give any orthodox designer the horrors. But they found out what they needed to know. They put together a hodgepodge plane that fits in perfectly with their headlong style of fighting.

The prime virtue of the Zero is that it handles well—climbs fast and maneuvers quickly. Its speed is good (more than 350 m.p.h. at 10,000 feet) and its service ceiling is exceptional: 36,000 feet. It is light (5,140 Ib. is normal flying weight) and rather small (wing span, 39.4 feet; length, 28.4 feet).

One type of Mitsubishi Finsei engine, essentially a copy of the U.S. Pratt & Whitney Wasp with features of the Wright Cyclone and British Bristol Hercules, is used in many of the Zeros. It is a 14-cylinder, double-banked, radial air-cooled engine, rated 1,050 h.p. when run on 95 to 100 octane fuel. Workmanship is spotty; some parts are finely finished, others are very crude. The weakest point is the cooling system; cooling area per cylinder is under 1,000 sq. in. compared to 2,800 in the genuine Wright Cyclone. The propeller is a duplicate of the U.S.-made Hamilton Standard. The air frame is very similar to the German Heinkel HE 113. Most of the other features are standard with many other types of fighter craft now in use. The armament is heavy but not unusually so: two 20-mm. cannon, one in each wing, and two 7.7-mm. (30 cal.) machine guns on either side of the nose.

Says a staff engineer of the Wright Aeronautical Corp. in a report to the Society of Automotive Engineers:

“The group responsible for the design did a very ingenious job. . . . This is undoubtedly a highly dependable, even though not highly developed, piece of equipment . . . probably produced under time and tooling limitations which we would consider nearly impossible.”

* Jap planes are numbered according to the last two digits of the year they were produced. In the Japanese calendar, 1940 A.D. was 2600.