P-39/P-400 Airacobra – Opponents over New Guinea.
With the attack on Pearl Harbor on December 7th, 1941, the Pacific war began. In conjunction with that attack, Japanese invasion forces also turned their attention to the shores of the Philippines and Indochina. The American and British forces were caught unprepared, and the Japanese also held a technical and tactical superiority. Progress was very rapid, and in a matter of several months, they were quite literally knocking on the door of the Australian continent, thousands of kilometers from their homeland.
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.
The Reisen, aka Zero
The Mitsubishi A6M, better known as the ‘Zero’ and ‘Zeke’, are known to even those that have little or no interest in the events that defined the far east and southwest Pacific wars. During the service career of these aircraft, they were called the ‘Reisen’, which is short for Rei Shiki Kanjo Sentoki, or Carrier Based Fighter Aircraft Type 0. Airacobras had the opportunity to go into combat against three versions of the Reisen – A6M2 Model 21, A6M3 Model 22 and the A6M3 Model 32.
The most interesting of these was the A6M3 Model 32. It decended directly from the A6M2 Model 21, and differed in the installation of the more powerful Sakae 21, and a redesigned wing with a wingspan shortened by 1.0m (3 ft).These changes were intended to improve certain characteristics, notably speed at medium altitudes. This did happen, as the speed increased to 545 km/hr at 6,000m, as opposed to 533km/hr at 4,550m. There were some penalties to pay, such as turn rate which the Japanese pilots preferred, and range, which put Guadalcanal at the limit of the Model 32’s reach, but did allow it to take part in important operations over the island. At the end of 1942, the designers returned to the original span, a better turn rate, and greater fuel carriage, bringing on the A6M3 Model 22. The armament remained the same, consisting of two 7.7mm machine guns in the fuselage, and two 20mm cannon in the wings. The production run of the Model 32 lasted from June, 1942, to the end of the year, and yielded a total of 343 aircraft.
The first unit to receive the new machine was the 2nd Kokutai, which was the first to take the type into combat over New Guinea in August, 1942. Progressively, other units took delivery as well, including Tainan Kokutai, and with front line units through 1943.
The shortened wing span and the clipped wing changed the silhouette of the type significantly. The difference was significant enough to misidentify it as a new type altogether, and allocate it a new reporting name, ‘Hap’, and later, ‘Hamp’. ‘Hap’ was used in the American code system until the intervention of General Henry H. ‘Hap’ Arnold, who was not particularly pleased that his name was associated with lists of shot down aircraft. When it was realized that the ‘Hamp’ was a version of the Reisen, the code name was dropped once and for all, and ‘Zero’ and ‘Zeke’ were used.
Notes: 1) Kokutai – Air group equivalent to a regiment 2) Reisen – Japanese designation for the fighter that is historically remembered as the ‘Zero’ and ‘Zeke’. 3) TRG Tactical Reconnaissance Group – US Army Air Force unit dedicated to tactical reconnaissance.