With long lead times in aircraft production from inception to production—up to four years for airframes and more than that for engines—timing and strategic decisions were extremely important. Both Germany and Japan caught aircraft modernization at the right time, that is, during the decade of the 1930s, when aircraft technology changed faster and more profoundly than at any time before or since. Furthermore, Japan’s penchant for secrecy enabled that country to keep the West unaware of what it had accomplished. Washington discounted reliable reports about the quality of Japanese aircraft, including reports from Claire Chennault, then supervising the Chinese air force.
Even though the Japanese air force was superbly equipped and trained at the outset of the conflict, it was in fact too small for world war. In December 1941 Japan had fewer than 3,000 combat-ready aircraft (the army had about 1,500 planes and the navy another 1,400). The vast majority of these were, however, of modern design (although several models with fixed, “spatted” landing gear gave a deceptively obsolete appearance) and were well suited for long-range operations. Japan emphasized maneuverability and long range in its fighters, and long range and bomb capacity in its bombers.
The weak design point of Japanese aircraft was their engines, in large part because of materials shortages, inferior lubricants, and inadequate quality control. Japan also continued to rely on prewar aircraft designs. Its basic design types—the Zero, the Betty, and the Val—all flew throughout the war. And Japan largely ignored defensive aircraft. Japan wanted a strike force capable of carrying out long-distance missions and inflicting maximum damage. Japanese pilots were superbly trained and had gained extensive combat experience against the Russians and the Chinese in the late 1930s, but Japan lost air supremacy in the great land-sea battles of 1942. Midway cost the navy four carriers and the lives of hundreds of experienced airmen. Guadalcanal was even more expensive; it became a “meat grinder” battle, in which Japan lost perhaps nine hundred aircraft, and, because Japanese bombers had relatively large crews (the Betty required seven men), it lost some twenty-four hundred trained pilots and aircrew. After Guadalcanal the United States launched many more carriers and vastly more aircraft (many of which were newer types), while the Japanese were forced for the most part to make do with updated versions of earlier aircraft, without veteran pilots to fly them.
By far the best and most famous Japanese fighter of the Pacific war was the Mitsubishi A6M Reisen (Zero, known as Zeke to the Americans but generally called Zero by all nations—eventually even by the Japanese, who nicknamed it Zero-sen). An excellent original design, it entered service in 1940. More Zeros (10,449) were built during the war than any other Japanese warplane. The A6M2 model that led the attack at Pearl Harbor had a speed of 332 mph and the exceptional range of 1,930 miles. It was exceptionally light; the fuselage was skinned with almost-paper-thin duralumin, and there was no seat armor; nor were its gas tanks self-sealing. At 6,264 pounds loaded, the A6M was almost half a ton lighter than the F4F Wildcat. It was also as maneuverable as any fighter of the war. The Zero had a surprisingly heavy armament—two 7.7-mm machine guns in the upper fuselage and two wing-mounted slow-firing 20-mm cannon. It could also carry 264 pounds of bombs. It was, however, deficient in structural strength. Based on bitter experience, U.S. pilots developed tactics to defeat the Zeros. Pairs of F4Fs, using the “Thach weave,” could handle four or five Zeros. The Zero went through a succession of models. The final (1945) A6M8 model had a 1,560-hp engine—60 percent more powerful than the engine in the A6M2—and could achieve 356 mph.
The main U.S. opponents of the Zero early in World War II were the army P-39 Airacobra and P-40 Warhawk and the navy/marine F4F Wildcat. The Bell P-39 Airacobra entered service in 1941. Its design centered on its unique armament—a 37-mm cannon firing through the middle of the nose cone—which dictated the entire structure of the aircraft. The engine was mounted in the center of the fuselage, behind the pilot, and the driveshaft to the propeller did double duty as a 37-mm cannon! The P-39 also had retractable tricycle landing gear positioned under its nose—the first such arrangement in a fighter. At 8,300 pounds, it was significantly heavier than the Zero, although its speed of 385 mph was faster. It had a range of 650 miles. The P-39 had one 37-mm cannon, four machine guns, and 500 pounds of bombs. No match for the Zero in one-on-one combat, the P-39 excelled in ground support operations. Of 9,558 P-39s produced during the war, fully half went to the Soviet Union for tactical support.
The Grumman F4F Wildcat entered service in December 1940. Powered with a 1,200-hp air-cooled engine, it was, at 7,000 pounds, only slightly heavier than the Zero and as fast as it (331 mph), but not nearly as maneuverable. Its range was 845 miles, and it was armed with six machine guns and 200 pounds of bombs. The F4F-4 (1941) had a speed of 318 mph and a range of 770 miles. The Wildcat was also quite strong. Although the Zero could easily outmaneuver the P-40 and F4F, U.S. Navy and Marine pilots developed tactics enabling them to utilize their heavy (.50-caliber) machine guns to cut the Zeros apart. The Wildcat was also faster than the Zero in a turning dive. The F4F remained in manufacture (8,000 produced) through the end of the war for service on escort carriers.