Early War Japanese Air Supremacy – the “Zero”

After the battles of Midway and the Coral Sea, the lightning fast expansion was slowed. The road to Australia for the Japanese was blocked by Port Moresby. After unsuccessful landing attempts, whose failure was ensured by the cruel defeat in the Coral Sea, the attempt was made to take the target over land, and the complicated conditions of the New Guinea jungle and the Owen Stanley mountain range proved to be insurmountable.

As a result, the Japanese continued to press air attacks. These were made from bases along the north-eastern shore of New Guinea at Lae, Salamaua, and especially later from Buna.

The brunt of the combat with units equipped with the Airacobra was carried out in 1942 by the Imperial Japanese Naval Air Force, notably by two units – the Tainan Kokutai1 and the 2nd Kokutai, besides the vanguard role played by the 4th Kokutai. This was a mixed unit with fighters and bombers in its inventory.

The unit arrived at Lae, just several days after the base was secured by Japanese ground forces on March 11th, 1942. Attacks on Post Moresby began immediately, and Lae had seven Reisens2 available. There was a reorganization of the unit on April 1st, with the 4th Kokutai becoming exclusively a bomber unit, and her fighter assets were formally turned over to the Tainan Kokutai. On dividing the aircraft, pilots were also reassigned accordingly. Tainan Kokutai is without question, the best known unit within the Japanese forces operating during World War Two. Out of its ranks came the greatest number of aces, including Saburo Sakai, and the most successful Japanese fighter ace of all time, Hiroyoshi Nishizawa. New Guinea was reached in April, 1942, and the unit arrived at Rabaul by the transport ship ‘Komaki Maru’, and then proceeded by air to Lae on April 17th. On April 25th, there twentyfour Reisens at Lae. From April to the early August, the unit conducted 51 raids on Port Moresby. Claims of victories were, as they were all over the world, more or less exaggerated. According to the pilots, there were 246 enemy aircraft shot down (of which 45 were probables). Other victories were claimed during combat directly over the bases at Lae and Buna. The majority of the opponents were identified as P-39s, which, in a maneuvering dogfight with a Zeke, had no chance. They themselves lost twenty aircraft to various causes, including crashes.

The turning point came with the American landings at Guadalcanal on August 7th, 1942. Tainan Kokutai dedicated all of its strength to the liquidation of the landings, and the battle for Port Moresby, while Australia took a back seat. The unit began using Rabaul as its base, since it was closer to Guadalcanal than Buna.

In the battle over New Guinea, the unit was replaced by the 2nd Kokutai. It was formed on the last day of May, 1942, as a mixed unit operating both fighters and bombers. After two months of equipping and training, this unit set out on the transport converted to escort carrier ‘Yawata Maru’, and headed southeast. Primarily, the unit was committed to fighting in the New Hebrides. The Japanese never did reach these islands, and the 2nd Kokutai landed at Rabaul in mid-August. The first meeting of these pilots with Airacobras came on the 24th of August on an attack on Rabi, southeast of Port Moresby. The Japanese, with no losses to themselves, claimed nine kills, two of which were probable. Further attacks followed on the 26th and 27th of August, but this time with the loss of two bombers and six Reisens (four from Tainan Kokutai). Attacks on Port Moresby continued by the 2nd Kokutai flying from Buna up to September 8th, and then came operations in support of counter offenses in an attempt to push the Americans back from Guadalcanal.

On November 1st, 1942, came a reorganization of the IJNAF, affecting the units in question, with Tainan Kokutai becoming the Kokutai 251, and the 2nd becoming the Kokutai 582.

Further combat, where units flying the Airacobra were met, came during Operation ‘I’ (in Japanese I-go Sakusen). This operation, personally overseen by the architect of the attack on Pearl Harbor, and the head of the Japanese Navy, Admiral Isoroku Yamamoto, took place between the 7th and 14th of April, 1943, and its goal was to regain the initiative in the southwest Pacific. Within this operation, the Japanese undertook massive attacks on Post Moresby (April 12th), and Milne Bay (April 14th). The entire venture ended in failure, despite minimal losses, Yamamoto was killed several days later thanks to the breaking of encryption codes and P-38s waiting for him as a result, and the Japanese forces found themselves strictly on the defensive, which eventual led to final defeat.

Over 1943, the Imperial Japanese Army Air Force also began to commit to New Guinea. Fighter units equipped with the Ki-43 Hayabusa (dubbed ‘Oscar’ by the Allies) and the Ki-61 Hien (‘Tony’), as well as bomber units equipped with light bomber Ki-48 (‘Lily’) and Ki-49 Donryu (‘Helen’) heavy bombers. These units suffered greatly at the hands of American fighters, notably the P-38 Lightning and P-47 Thunderbolt.

Getting back to the most intensive fighting that occurred during the spring and summer of 1942 involving the Airacobra, claims by the two best known fighter aces of the Tainan Kokutai, Hiroyoshi Nishizawa and Saburo Sakai, included quite the list of the P-39. Nishizawa claimed 21 confirmed P-39 kills plus five probables between May 1st and June 25th, 1942. His best results came over Port Moresby on May 17th, when he claimed five Airacobras confirmed and one probable. Sakai claimed 22 confirmed Airacobra kills and one probable between April 11th and August 2, 1942. He also could boast about downing five P-39s in one day, on June 16th. Although these numbers are evidently inflated, there is no doubt that the Zeke in the hands of a capable Japanese pilot, had a definite advantage. The Japanese fighter pilots were aware of this fact and did not consider the Airacobra in the same league. The skies over New Guinea were not much safer even in 1944, when the Japanese air forces presented no great danger. Between January and August, the 71st TRG3 lost a minimum of nine Airacobras over the space held by the enemy.


At the beginning of the Pacific war neither Japan nor the United States possessed large numbers of warplanes, despite unprecedented programs of prewar aircraft development and production. Thus, early Pacific war air operations on both sides were undertaken with what were small forces compared with those engaged in Europe. Most British aircraft were, of course, in Europe, although there were air assets in Asia, in such places as Singapore, and Commonwealth air forces in Australia and New Zealand.

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.



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