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Mitsubishi A6M2

Mitsubishi A6M2



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The Mitsubishi Jukogyo company began producing the Mitsubishi A5M4 fighter for the Japanese Air Force in 1934. Three years later the designer, Jiro Horikoshi, started work on an improved version, the Mitsubishi A6M2. The aircraft made its maiden flight on 1st April, 1939.

The Mitsubishi A6M2, nicknamed the Zero, had a maximum speed of 332 mph (534 km) and had a range of 1,930 miles (3,105 km). It was 29 ft 9 in (9.15 m) long with a wingspan of 39 ft 4 in (12.10 m). The aircraft was armed with 2 machine-guns and could carry 264 lb (120 kg) of bombs.

The Zero was the main strike aircraft used at Pearl Harbour and in the early stages of the Pacific War dominated the skies. A large number were shot down during the Battle of Midway and it gradually became outperformed by the latest allied aircraft. During the Second World War Mitsubishi A6M2 produced 11,283 of these aircraft.


Mitsubishi A6M Zero (1939)

Popularly known as the ‘Zero’, the Mitsubishi A6M was the world’s most capable carrier-based fighter at the time of its appearance, out-performing all land-based contemporaries. Latterly outclassed, it remained in service until the end of the war. This A6M2 was on strength with the 2nd Sentai, 1st Koku Kentai and was operating from the carrier Hiryu during the Battle of Midway in June 1942. In the course of the battle, the IJN put up large formations of Zero fighters for protection, but these could not prevent the loss of four Japanese carriers by the U.S. Pacific Fleet.

The brainchild of prolific designer Jiro Horikoshi, the Mitsubishi A6M (Allied reporting name ‘Zeke’) was schemed as a replacement for the same company’s A5M carrier fighter. A cantilever low-wing monoplane, the A6M1 prototype completed its maiden flight in April 1939 and in this form was powered by a Mitsubishi Zuisei 13 radial engine. In production form, the A6M2 of early 1940 introduced a new Nakajima Sakae 12 powerplant and was armed with a pair of wing-mounted 20mm (0.79in) cannon, plus two machine guns in the nose. The new engine was a result of early testing, in which the A6M1 had demonstrated excellent performance with the exception of maximum speed, which had failed to meet the original specification.

The Japanese attack on Rabaul in January 1942 was typical of the whirlwind successes in which the A6M was pitched in the initial phase of the war in the Pacific. Air power on Rabaul, the key strategic base on the island of New Britain, was provided by Australian Hudson light bombers and Wirraway reconnaissance aircraft, but there was no genuine fighter cover. On 20 January, a force of 120 A6M2s, Aichi D3A1s and Nakajima B5Ns took off from the carriers Zuikaku, Shokaku, Kaga and Akagi, attacking installations at Rabaul. Slicing through gallant opposition put up by the Wirraways, the IJN aircraft paved the way for a task force of 5300 men that landed at Simpson Harbour on 23 January, securing the port and the airfield at Kavieng. After capturing Rabaul, Japan established a major base and proceeded to land on mainland New Guinea, advancing towards Port Moresby and Australia.

As early as 1937 the Imperial Japanese Navy began searching for a craft to replace its A5M carrier-based fighters. That year it issued specifications so stringent that only Mitsubishi was willing to hazard a design. Specifically, the navy wanted a fighter of prodigious range and maneuverability, one able to defeat bigger land-based opponents. A design team headed by Jiro Horikoshi originated a prototype in 1939. The A6M was a study in aerodynamic cleanliness despite its bulky radial engine. It had widetrack undercarriage for easy landing and was heavily armed with two cannons and two machine guns. Tests proved it possessed phenomenal climbing and turning ability, so it entered production in 1940, the Japanese year 5700. Henceforth, the new fighter was known officially as the Type 0, but it passed into history as the Reisen, or Zero.

A small production batch of 30 Zeroes was sent to China in the summer of 1940 for evaluation, and they literally swept the sky of Chinese opposition. The official military designation for the new warplane was Navy Type 0 Carrier Fighter and in 1940 initial combat trials were undertaken in China by a preproduction batch. The antiquated Polikarpov fighters flown by the Chinese proved to be no match for the Zero. It was in the course of these operational trials that the Zero recorded its first aerial victory, in September 1940. By the end of that year, the Zero detachment had claimed 59 victories without loss.

Such prowess was duly noted by Claire L. Chennault, future commander of the famed Flying Tigers, but his warnings were ignored. Zeroes subsequently spearheaded the Japanese attack on Pearl Harbor in December 1941, and over the next six months they ran roughshod over all Allied opposition.

Once entering combat in World War II, the highly agile A6M2 proved itself an immediate success, quickly gaining aerial supremacy during the Imperial Japanese Navy’s campaigns in the East Indies and Southeast Asia. The A6M2 was the IJN’s premier fighter during the raid on Pearl Harbor in December 1941, in which eight Zero fighters were lost from a total of 105 involved in the surprise attack on the U.S. Navy fleet. The A6M remained the service’s pre-eminent fighter in theatre as fighting extended to Malaya, the Philippines and Burma. Along the way, it demonstrated its superiority against lesser Allied types in theatre, including the Brewster Buffalo, Curtiss P-36 and P-40 and Hawker Hurricane fighters. Japan’s leading ace of the Pacific war, Saburo Sakai, flew a Zero, who is believed to have achieved 64 aerial kills.

An improved A6M3 entered service in spring 1942, now powered by a Sakae 21 with two-stage supercharger. Not only supremely manoeuvrable, the Zero was also well equipped for fighting at the extended ranges encountered in the Pacific theatre. The aircraft could carry a fuel tank under the fuselage to increase the endurance of its long-range fighter patrols. Even before the arrival of the powerful Hellcat, however, the A6M had begun to suffer at the hands of the Grumman F4F Wildcat, which, although inferior in terms of performance and agility, was better able to withstand battle damage and possessed heavier-hitting armament, self-sealing tanks and armour protection for the pilot. While the Zero was always fast, it was also underpowered, and as a result the design stressed lightweight construction. This, in turn, led to a fighter that was vulnerable to even machine gun fire, and had little in the way of armour protection.

However, following the Japanese defeat at Midway in June 1942, the fabled fighter lost much of its ascendancy to new Allied fighters and a growing shortage of experienced pilots. New and more powerful versions of the Zero were introduced to stem the tide, but relatively weak construction could not withstand mounting Allied firepower. Furthermore, the additional weight of new weapons and equipment eroded its famous powers of maneuver.

Changing Fortunes

The Battle of Midway of June 1942 represented a watershed for the Zero, and thereafter the Japanese fighter began to be increasingly outclassed by U.S. opposition, in particular the U.S. Navy’s Grumman F6F Hellcat, which proved to be faster than the Zero at all altitudes. While the A6M3 version had helped to offset the appearance of the Wildcat, it could do little in the face of the Hellcat.

In an effort to wring additional performance out of the basic airframe, the IJN introduced the A6M5, with Sakae 21 and an improved exhaust system. This version was actually slower than the A6M2, but enjoyed a superior rate of climb and was faster in the dive. It was also built in greater numbers than any of the other Zero models. As the tide of the war turned against the Japanese, the Zero was also used for kamikaze raids, and in one action, five A6M5s sunk the U.S. Navy carrier St Lo and damaged three others in October 1944.

The last models in the Zero line comprised the A6M6 of late 1944, with a water-methanol boosted Sakae 31, and the A6M7 fighter/dive-bomber of mid-1945 with a rack under the fuselage for the carriage of a single 250kg (551lb) bomb. In total, in excess of 10,000 Zero fighters were completed, including a floatplane version built by Nakajima as the A6M2N (Allied reporting name ‘Rufe’). As such, it was the most prolific Japanese fighter of all time.

Although the A6M’s vulnerability to the Hellcat in particular was clear by the time of the Battles of the Philippines and Leyte Gulf in 1944, the lack of an adequate replacement meant the Zero was forced to soldier on in IJN service until the bitter end.

By 1945 most A6Ms had been converted into kamikazes in a futile attempt to halt the Allied surge toward the homeland. A total of 10,964 were constructed.

The legendary A6M (the dreaded Zero) was the first carrier-based fighter in history to outperform land-based equivalents, and it arrived in greater quantities than any other Japanese aircraft. Despite the Zero’s aura of invincibility, better Allied machines gradually rendered it obsolete.

A6M5c Type 0 Model 52

Considered the most effective variant, the Model 52 was developed to face the powerful American Hellcat and Corsair, superior mostly for engine power and armament. The variant was a modest update of the A6M3 Model 22, with non-folding wing tips and thicker wing skinning to permit faster diving speeds, plus an improved exhaust system. The latter used four ejector exhaust stacks, providing an increment of thrust, projecting along each side of the forward fuselage. The new exhaust system required modified “notched” cowl flaps and small rectangular plates which were riveted to the fuselage, just aft of the exhausts. Two smaller exhaust stacks exited via small cowling flaps immediately forward of and just below each of the wing leading edges. The improved roll-rate of the clipped-wing A6M3 was now built in.

Sub-variants included:

* “A6M5a Model 52a «Kou»,” featuring Type 99-II cannon with belt feed of the Mk 4 instead of drum feed Mk 3 (100 rpg), permitting a bigger ammunition supply (125 rpg)

* “A6M5b Model 52b «Otsu»,” with an armor glass windscreen, a fuel tank fire extinguisher and the 7.7 mm (.303 in) Type 97 gun (750 m/s muzzle velocity and 600 m/1,970 ft range) in the left forward fuselage was replaced by a 13.2 mm/.51 in Type 3 Browning-derived gun (790 m/s muzzle velocity and 900 m/2,950 ft range) with 240 rounds. The larger weapon required an enlarged cowling opening, creating a distinctive asymmetric appearance to the top of the cowling.

* “A6M5c Model 52c «Hei»” with more armor plate on the cabin’s windshield (5.5 cm/2.2 in) and behind the pilot’s seat. The wing skinning was further thickened in localised areas to allow for a further increase in dive speed. This version also had a modified armament fit of three 13.2 mm (.51 in) guns (one in the forward fuselage, and one in each wing with a rate of fire of 800 rpm), twin 20 mm Type 99-II guns and an additional fuel tank with a capacity of 367 L (97 US gal), often replaced by a 250 kg bomb.

The A6M5 had a maximum speed of 540 km/h (340 mph) and reached a height of 8,000 m (26,250 ft) in nine minutes, 57 seconds. Other variants were the night fighter A6M5d-S (modified for night combat, armed with one 20 mm Type 99 cannon, inclined back to the pilot’s cockpit) and A6M5-K “Zero-Reisen”(model l22) tandem trainer version, also manufactured by Mitsubishi.


Japan’s Mitsubishi A6M Zero Fighter was Amazing, Except for 1 Weakness

How effective can an aircraft carrier-based fighter be without carriers?

Here's What You Need To Remember: The Wildcat never exceeded the Zero in performance, but over time the non-existent armor protection and loss of entire carriers took a heavy toll on Japanese aviators, eroding their experience advantage. In 1943, new, much faster U.S. fighters such as the F6F Hellcat and F4U Corsair decisively won air superiority for the Allies.

Japan began the Pacific War with two major technological advantages over the U.S. Navy: the much more reliable Long Lance torpedo, and the Mitsubishi A6M Zero carried-based fighter, a design that defied expectations by outperforming land-based fighters when in it was introduced into service in 1940.

Designer Jiro Horikoshi maximized the Zero’s performance by reducing airframe weight to an unprecedented degree by cutting armor protection and employing an “extra super” duralumin alloy. Combined with an 840-horsepower Sakae 12 radial engine, the A6M2 Type Zero could attain speeds of 346 miles per hour, while exhibiting extraordinary maneuverability and high rates of climb. For armament, the Zero boasted two punchy Type 99 20-millimeter cannons in the wing—though only with sixty rounds of ammunition—and two rifle-caliber machine guns firing through the propeller.

The elegant airframe weighed only 1.85-tons empty, giving the Zero a tremendous range of 1,600 miles—very useful for scouting for enemy ships and launching long-distance raids. By comparison, Germany’s excellent contemporary Bf 109 fighter could fly only 500 miles, fatefully reducing its effectiveness in the Battle of Britain.

The Zero debuted fantastically in combat in July 1940, with thirteen land-based A6M2 Zeros shooting down twice their number of Russian-built I-16 and I-153 fighters in a three-minute engagement.

When Japan launched her surprise attack on Pearl Harbor, and on British and Dutch possessions in East Asia, the 521 Zeroes serving in the Japanese Navy quickly became the terror of Allied fighter pilots. U.S. Army P-39 Airacobras struggled to match the Zero’s high altitude performance. Even the pilots of agile British Spitfires found they were likely to be out-turned and out-climbed by a Zero.

The U.S. Navy at the time was phasing in the Grumman F4F Wildcat at the expense of the infamously awful F2A Buffalo. The tubby-looking Wildcat was heavier at 2.5 to 3 tons and had a range slightly over 800 miles. The Wildcat’s supercharged 1,200 horsepower R-1830 radial engine allowed it to attain speeds of 331 mph while armed with four jam-prone .50-caliber machine guns, or 320 mph on the heavier F4F-4 model with six machine guns and side-folding wings for improved stowage.

Thus the U.S. Navy’s top fighter was slower and less maneuverable than the Zero. But unexpectedly—after a rough start, and despite starting the war with less combat experience, Wildcat pilots managed to trade-off evenly with Zeroes. At Wake Island, just four Marine Wildcats helped repel besieging Japanese forces for two weeks and even sank the destroyer Kisaragi. In February 1942, Wildcat pilot Edward “Butch” O’Hare managed to shoot down three Japanese bombers and damage three more during a raid.

Though the Wildcat didn’t claim air superiority over the nimble Japanese fighters, they performed well enough to allow American dive and torpedo bombers to sink five Japanese aircraft carriers in the Battles of the Coral Sea and Midway—finally turning the tide of the war in the Pacific.

How did they pull it off?

The Zero’s lack of armor and a self-sealing fuel tank (which have internal bladders that swell to close off holes) meant they were infamously prone to disintegrating or catching fire after sustaining light damage. Meanwhile, once a Zero pilot expended his limited supply of 20-millimeter shells, the remaining rifle-caliber machine guns struggled to down better-armored Wildcats. Navy and Marine Wildcat pilots learned to make slashing attacks from above leveraging their superior diving speed. But it simply wasn’t always possible to avoid getting into a turning dogfight with a Zero.

Contemplating this problem, naval aviator John Thach, devised the tactic called the Thach Weave in which two Wildcats flying side-by-side laid a trap for pursuing Zeros. Both the “bait” and “hook” plane would complete two consecutive 90-degree turns towards each other, forming a figure eight. A Zero choosing to pursue the bait plane would end up having its tail in the sights of the hook.

After successfully testing the maneuver with Wildcat ace Edward O’Hare, John Thach had a chance to try his Thach Weave the Battle of Midway. On June 4, Thach’s six F4Fs of VF-3 squadron from the carrier Yorktown were escorting Devastator torpedo bombers when they were bounced by fifteen to twenty Zeros, one of which immediately set a Wildcat ablaze while another knocked out the radio on the Wildcat of Thach’s wingman.

Thach called on the radio for rookie pilot Ram Dibb to help him perform the Weave maneuver. Steve Erling’s book Thach Weave recounts what happened next:

“With so many enemy planes in the air, Thach was not sure anything would work, but the answer came when a Zero followed Dibb during one of his turns… Thach found himself angry that the young inexperienced Dibb was the target of this Zero. Wisdom called for a short burst of shells to hopefully cause the Zero to break off the pass, but it was apparent this Zero was not going to break off. Anger rising, Thach continued straight ahead, the firing button depressed, rather than ducking under the Zero. At last the Zero broke off, and as he passed close by, Thach could see flames pouring from its underside.”

“Continuing the weave now discouraged the Zeros from following the Wildcats in their turns, but one made the same mistake as Thach’s first kill, and when he was too slow in his pullout, Thach shot him down and added a third mark on his kneepad. Soon after, Dibb erased another enemy fighter converging astern of Thach and Macomber.

By then the Zeros had shot down all but two of the torpedo bombers and might have finished off the Wildcats. But at that moment, two squadrons of SBD dive bombers came screaming out from the clouds on the now unprotected Japanese carriers. The Zeros were too low and far afield to intercept them, and bomber proceeded to fatally cripple the carriers Akagi and Kaga.

The Thach Weave was subsequently adopted by other Navy and Marine squadrons, and top Japanese ace Saburo Sakai described the maneuver vexing a squadron mate’s attack run over Guadalcanal in his biography.

The Wildcat never exceeded the Zero in performance, but over time the non-existent armor protection and loss of entire carriers took a heavy toll on Japanese aviators, eroding their experience advantage. In 1943, new, much faster U.S. fighters such as the F6F Hellcat and F4U Corsair decisively won air superiority for the Allies. In the 1944 Great Marianas Turkey Shoot over the Philippine Sea, Allied fighters and flak gunners shot down over 500 Japanese warplanes for just 123 USN aircraft lost.

Both the Zero and Wildcat saw action through the remainder of World War II, many of the former ending their days as Kamikaze aircraft. The Wildcat carried on a little-known but surprisingly successful career with the U.S. and Royal Navies in the European theater, dueling French fighters over North Africa, flying from small escort carriers to hunt Nazi bombers and submarines, and even embarked on the last Allied air raid of the war, sinking a U-Boat in Norway on May 5, 1945.

Sébastien Roblin holds a Master’s Degree in Conflict Resolution from Georgetown University and served as a university instructor for the Peace Corps in China. He has also worked in education, editing, and refugee resettlement in France and the United States. He currently writes on security and military history for War Is Boring. This first appeared in December 2018.


The R-Area Air Force was created by the 8th Fleet on 28 August 1942 in response to Allied landing at Guadalcanal a few weeks earlier. It exclusively operated seaplanes in order to compensate for the lack of land bases in the Solomon Islands area. The unit's primary strength was drawn from the 11th Seaplane Tender Division, whose commander Rear Admiral Takatsugu Jōjima also became the commander of the R-Area Air Force. The squadrons from the division's four seaplane tenders (Chitose, Kamikawa Maru, Sanyō Maru and Sanuki Maru) formed two air groups. Eventually aircraft from other squadrons also joined the R-Area Air Force, such as from Kunikawa Maru. Their main base was at Shortland Islands, which was also the staging area for resupply convoys to Guadalcanal. The R-Area Air Force primary mission was to provide air cover for the resupply ships during their runs heading for Guadalcanal through the New Georgia Sound. On 5 September, they built a forward base at Rekata Bay on Santa Isabel Island, which enabled the seaplanes to attack Lunga Point on Guadalcanal. Nevertheless, due to being in range of Cactus Air Force, it was use only used as a staging point and the unit's seaplanes were not kept there for long at any given time. [1] [2] [3]

On 12 September, Chitose squadron had 16 Mitsubishi F1M and seven Aichi E13A floatplanes under Lieutenant Takeshi Horihashi, while Kamikawa squadron had two F1M floatplanes and 11 Nakajima A6M2-N float Zeros under Lieutenant Jirō Ono, both forming No. 1 group. Sanyō squadron had six F1M and two E13A floatplanes under Lieutenant Tadashi Yoneda, while Sanuki had six F1M floatplanes under Lieutenant (jg) Kaneshige Watanabe, both forming No. 2 group. [2] In the morning of 14 September, three float Zeros of Kamikawa under Lieutenant (jg) Masashi Kawashima flew from Rekata Bay to conduct a reconnaissance mission over Henderson Field and check whether the Imperial Japanese Army managed to capture the airfield in their assault. They were intercepted by seven US Navy Grumman F4F Wildcat fighters from Henderson Field and all of them were shot down for the loss of one Wildcat. [4] That afternoon, Rear Admiral Jōjima committed most of the R-Area Air Force strength in a dusk attack on Henderson Field. Lieutenant Horihashi (Chitose Hikōtaichō) led 19 F1M floatplanes, each equipped with two 60-kg bombs, while two float Zeros provided the escort. They bombed the airfield after the sunset but were intercepted by a combination of eleven US Navy and Marine Wildcat fighters. The attack cost the R-Area Air Force two F1M floatplanes (including Sanyō Buntaichō Lieutenant Yoneda killed in action) and one float Zero. [5]

The base at Rekata Bay was discovered by the Allies on 16 September and was subsequently targeted several times by the Allied aircraft. [1] [6] [7] In the morning of 5 October, aircraft from the aircraft carrier Hornet attacked Shortland Islands. No ships were hit but three Kawanishi H8K flying boats of Tōkō Air Group moored at Faisi were heavily damaged in strafing. Several F1M floatplanes under Lieutenant (jg) Watanabe (Sanuki Buntaichō) and two float Zeros of Kamikawa under Petty Officer Jirō Kawai intercepted the USN air strike and lost one F1M floatplane. Simultaneously, Cactus Air Force targeted Rekata Bay with several Douglas SBD Dauntless and Grumman TBF Avenger bombers, where they were intercepted by three float Zeros of Kunikawa under Warrant Officer Haruzō Ōta. In the engagement Ōta managed to shot down one SBD dive bomber. [8]

Since regular resupply runs by destroyers only could not deliver heavy equipment on Guadalcanal, such as artillery, seaplane tenders Chitose and Nisshin were used as high-speed transports along the destroyers during October. [9] Frequent missions to provide air cover over resupply convoys, combined with occasional base defences, took a heavy toll on the R-Area Air Force. By 8 October, the remaining strength was five A6M2-N float Zeros of Kamikawa, 12 F1M floatplanes of Chitose, Sanuki, Sanyō and Kunikawa, and nine E13A floatplanes of Chitose and Sanyō. [10] In the evening of 8 October, Lieutenant (jg) Watanabe led eight F1M floatplanes to cover high-speed transport Nisshin and five destroyers headed for Guadalcanal. They intercepted a strike of SBD and TBF bombers escorted by 11 Wildcat fighters. While the ensuing air combat accounted for two F1M floatplanes and one Wildcat fighter shot down, the US bombers failed to score any hits on the ships. [11]

On 12 October, 14th Air Group with nine float Zeros joined the R-Area Air Force (delivered by Kiyokawa Maru) and the force continued to provide air cover for the regular resupply runs by destroyers. [1] On 7 November, Lieutenant Hiderō Gotō led five float Zero of 802nd Air Group (redesignated 14th Air Group) to cover 11 destroyers on their resupply run to Guadalcanal, when they intercepted a large strike from Cactus Air Force. The resulting combat accounted for the loss of all floatplanes, however, in return they shot down US Marine ace Joe Foss. [1] [12] [13] Japanese made the final attempt to resupply Guadalcanal with 11 large transports and 11 destroyers under Rear Admiral Raizō Tanaka on 14 November. The R-Area Air Force provided eight F1M floatplanes under Lieutenant (jg) Shōichi Koyanagi of Kunikawa to cover the convoy. The air combat over the ships resulted in the loss of three F1M floatplanes. The next day they provided ten more F1M floatplanes under Lieutenant Horihashi and Lieutenant (jg) Watanabe and, lost two more, one of which carried Watanabe, who was killed in action. In addition, the resupply effort failed since only four transports eventually reached Guadalcanal but were all destroyed before they could unload their cargo. [14] [15]

The Imperial General Headquarters decided to abandon the effort to recapture Guadalcanal and they planned a withdrawal of land units for January and February 1943. The R-Area Air Force provided air cover for the evacuation during the Operation KE. [16] They continued to operate throughout 1943, as the Allies moved up the Solomon Islands. [1] [17] Pending the loss of New Georgia, in late August the forward base at Rekata Bay was evacuated. [17]


Mitsubishi A6M2 - History

    On May 19, 1937, the Japanese Imperial Navy submitted specifications for a new navy fighter to supersede the Mitsubishi A5M, Navy Type 96 Carrier Fighter which had just become operational. The requirements called for were:

      • Maximum speed of 270 kt @ 4,000 m.
      • Climbing speed of 3,000 m in 9 min 30 sec.
      • Endurance of 1.5 to 2 hours at normal rated power.
      • Endurance of 6 to 8 hours at economical speed with drop tanks.
      • Armament of two 20 mm cannon and two 7.7 mm machine guns.
      • Provisions for two 60 kg bombs.
      • Provision for full radio and direction finder.
      • Takeoff run less than 70 m with a 27 knot headwind.
      • Maneuverability at least equal to the A5M.

    The Navy ordered two prototypes and plans were submitted by Nakajima and Mitsubishi. Nakajima elected to drop their proposal for a fighter design and Mitsubishi submitted their design led by designer Jiro Horikoshi. The Mitsubishi A6M1 prototype was an all metal, low-wing monoplane with retractable gear, and powered by a 780 hp (580 kW) Mitsubishi Zuisei 13 engine. During flight testing, the two-blade variable-pitch propeller was replaced with a three-blade variable pitch propeller. Apart from maximum speed, all requirements were met or exceeded. 5 The Navy had authorized the production of an initial batch of A6M2s and military trials progressed rapidly. While flight testing the A6M1, a new power plant passed its Navy acceptance tests, and the 925 hp (690 kW) Nakajima NK1C Sakae 12 , which was slightly larger than the Zuisei , was installed in the third A6M2 prototype. The initial trials were completed in July 1940 and the navy assigned fifteen A6M2s to combat trials in China.

    In China, the A6M2s reinforced with a number of production aircraft, destroyed 99 Chinese aircraft with a loss of only two of their own. The aircraft was accepted for production on July 1940 as Navy Type 0 Carrier Fighter Model 11, and in September 1941 were prepared for the impending war with the Allies. Modifications were introduced during production and the A6M2 rear spar was reinforced and manually folding wingtips were incorporated to allow clearance on the carriers deck elevators. The modified aircraft was designated Navy Type 0 Carrier Fighter Model 21. The A6M2 Model 21 was the version utilized at Pearl Harbor and throughout the Pacific during the early stages of the war.

    With its maximum speed of 331 mph (532 km/h) and the ability to climb to 6,000 m in 7 minutes 27 seconds, it possessed an ascendancy over any other fighter type in the Pacific. When the war began, the Japanese Navy had 328 A6M2s in first line units. On December 7,1941, the Japanese Imperial Navy launched 353 aircraft from six carriers in a surprise attack, against US military installations at Pearl Harbor, on the island of Oahu, Hawaii. The aircraft included in the raid were A6M2s, Nakajima B5Ns and Aichi D3As.

    The A6M possessed many shortcomings, which were only to be revealed six months later when a virtually intact specimen was obtained. On June 3, 1942, Flight Petty Officer Tadayoshi Koga left the flight deck of the carrier Ryujo in his Mitsubishi A6M2 Model 21 fighter as part of a task force assigned to attack Dutch Harbor in the Aleutian Islands. His A6M2, which had been built in February, was on its first operational mission. On his way back to the Ryujo, Koga found that two bullets had punctured his fuel supply and he informed his flight commander that he intended to land on Akutan Island, designated as an emergency landing field. Koga did not make the landing field and instead made a forced landing in a marsh where the aircraft flipped over, in which he broke his neck and was killed. Five weeks later, a US Navy PBY Catalina, making a routine patrol, discovered the Japanese fighter upside down in the marsh. This single fighter was probably one of the greatest prizes of the Pacific war. Hardly damaged, it was shipped back to the USA where it was exhaustively tested. Information gathered during testing of the A6M2 prompted the American aircraft manufacturer Grumman, to lighten the Grumman F4F Wildcat, 6 and install a larger engine on the Grumman F6F Hellcat. 7 The Zero also lacked armor protection for the pilot and self-sealing-fuel tanks and was overrated in some areas, including its fabled maneuverability. 8

    Modified Zeros, assigned to Air Group 201 in the Philippines, were the first Japanese aircraft used on planned suicide missions against American surface vessels. Air Group 201, assisted by volunteer pilots from Air Group 601 and other Navy units in the area, became the first Kamikaze (Divine Wind) suicide squadron in the Japanese Naval Air Force. The outstanding successes gained by this form of attack led to the formation of other Kamikaze units, and the bomb-carrying Zeros became the prime suicide attack bombers of the Navy.

    More Zero-Sens were produced than any other wartime Japanese aircraft. Mitsubishi alone produced 3,879 aircraft of this type, and Nakajima built 6,215. All together, with the 844 trainer and floatplane variants produced by Sasebo, Hitachi and Nakajima, production of the A6M series aircraft totaled 10,938 aircraft. The Zero-Sen possessed complete mastery in the air over the Pacific until the Battle of Midway in June 1942, which became the actual turning point of the Pacific War, although very few knew it at the time.

    The value of the Zero steadily declined and its lowest point was reached when it was selected to lead the Navy's Air Force in mass suicide attacks. The installation of the Kinsei engine brought Zero-Sen closer to Allied standards attained at that stage in the war, but the overwhelming industrial capacity of the United States made it apparent that victory for the Allies had become a foregone conclusion. The airplane that started the Pacific war was no longer able to fight it—nor was the nation that conceived it.

Specifications:
A6M2 - Model 21 A6M5 - Model 52
Dimensions:
Wing span: 39 ft 4 7/16 in (12 m) 46 ft 1 1/16 in (11 m)
Length: 29 ft 8 11/16 in (9.06 m) 29 ft 11 3/32 in (9.121 m)
Height: 10 ft 0 1/16 in (3.05 m) 11 ft 6 5/32 in (3.509 m)
Weights:
Empty: 3,704 lb. (1,680 kg) 4,136 lb. (1,876 kg)
Loaded: 5,313 lb (2,410 kg) 6,025 lb (2,733 kg)
Performance:
Maximum Speed: 331.5 mph (288 kt)
@ 14,930 ft (4,550 m)
351 mph (305 kt)
@ 19,685 ft (6,000 m)
Service Ceiling: 32,810 ft. (10,000 m) 38,520 ft. (11,740 m)
Maximum Range: 1,930 miles (3,107 km) 1,194 miles (1,922 km)
Powerplant A6M2: Powerplant A6M5:
One Nakajima NK1C Sakae 12,
fourteen cyl., air-cooled, radial engine
rated at 940 hp for takeoff and 950 hp @ 13,780 ft (4,200 m), driving a three-blade metal propeller.
One Nakajima NK1F Sakae 21,
fourteen cyl., air-cooled, radial engine
rated at 1,130 hp for takeoff and 980 hp @ 19,685 ft (6,000 m), driving a three-blade metal propeller.
Armament:
Two forward-firing 7.7 mm Type 97 machine-guns in the upper fuselage and
two wing-mounted 20 mm Type 99 cannon with two external 132 lb (60 kg) bombs.

Endnotes:
1. Heiner Emde and Carlo Demand. Conquerors of the Air. New York: Viking Press, 1969.
2. David Mondey. The Concise Guide to Axis Aircraft of World War II. New York: Smithmark Publishers, 1996. 194.
3. Robert D. Loomis. Great American Fighter Pilots of World War II. New York: Random House, 1961. 47-48.
4. Rene J. Francillon, Japanese Aircraft of the Pacific War, Mitsubishi A6M Reisen (Zero Fighter). Annapolis, Maryland: Naval Institute Press, 1995. 362.
5. Ibid. 363-364.
6. Richard Thruelsen. The Grumman Story. New York: Praeger Publishers, Inc., 1976. 181.
7. Ibid. 193.
8. Robert F. Dorr, Why the P-38 Flunked in Europe. Aviation History. May 2014. 29.

©Larry Dwyer. The Aviation History Online Museum. All rights reserved.
Created October 11, 1996. Updated March 25, 2014.


[4] ZERO IN DECLINE

* The Zero became the most prominent Japanese fighter, so much so that in the popular American press any radial-engine fighter with red "meatballs" on its wings was often called a "Zero". The Allies were thoroughly intimidated by the Zero. However, although the Grumman F4F Wildcat fighter was inferior to the Zero in maneuverability and in almost all aspects of performance, the ruggedly built Grumman could easily take ten times more punishment than the lightly-built Zero, and could also escape a Zero by going into a dive. After suffering through a nasty learning curve, US Navy and Marine Wildcat pilots learned tactics to allow them to more or less hold their own against the Zero.

Allied pilots were particularly helped when a Zero fighter fell into American hands. On 4 June 1942, Japanese aircraft attacked the American military base at Dutch Harbor in the Aleutians. One Zero fighter was hit during the raid, severing its oil line. The pilot of the damaged Zero, 19-year-old Flight Petty Officer Koga Tadayoshi, knew he couldn't make it back to his carrier, the RYUUJOU, and decided to land his aircraft on the island of Akutan, 40 kilometers (25 miles) away.

Akutan had been designated for emergency landings, with a Japanese submarine standing off the island to assist pilots who were forced down. Koga attempted to land on what he thought was a grassy meadow while two of his wingmates watched on. The grassy meadow turned out to be a marsh, and when Koga touched down, the Zero's main gear dug into the mud and the aircraft flipped over on its back. Koga's two wingmates had orders to prevent a Zero from being captured, but as they were not certain Koga was dead, they were reluctant to shoot up the overturned Zero and destroy it. Koga did not emerge, and his wingmates finally had to depart in order to make it back to the RYUUJOU.

In fact, Koga was dead. His neck had been broken when the aircraft flipped over. On 10 July 1942, a US Navy Consolidated PBY Catalina flying boat on patrol spotted the Zero, then setting down on the waves so the crew could go ashore and examine the downed fighter. They excitedly reported their find to their superiors and an expedition was sent to recover the downed aircraft. Navy workers laboriously dragged the Zero onto a skid and pulled out of the bog with a tractor, put the aircraft on a barge, and brought it to Dutch Harbor. Koga's body was buried on Akutan, to be repatriated back to Japan after the war.


At Dutch Harbor, the Zero -- which was still on its back -- was righted, cleaned up, and put in a crate for shipment to San Diego. The Zero's wings could not be detached in any convenient way, and so the crate was very big and clumsy. The inability to remove the wings was a nuisance for the Japanese as well, but adding such a feature would have increased the aircraft's weight.

After arrival in San Diego, the Zero, which turned out to be an A6M2 Model 21 with a manufacturing date stamp of 19 February 1942, was repaired. One problem was that the propeller was damaged beyond repair, but that was easy to fix, since the Sumitomo design was a straight copy of a readily available Hamilton Standard propeller. Flight evaluations of the captured aircraft began in late September 1942, and demonstrated the performance capabilities and limitations of the type.

While the Zero was supremely maneuverable at low speeds, its controls became heavy at high speeds, and it rolled left much more easily than it rolled right. Also, due to its float-type carburetor it tended to stall under negative gees, as would be encountered if the Zero was climbing and then had to bob back downward while remaining upright. An American fighter could escape the Zero by bobbing up, diving while the Zero's engine stalled, and then rolling to the right. Japanese writer Okumiya Masatake, author of the classic book ZERO, claimed that the loss of Koga's Zero was no less serious than the Japanese defeat at Midway. That was clearly an exaggeration the Allies would have got its measure sooner or later, but it was still lucky they managed to capture one in the first year of the war in the Pacific.

* With the introduction of more advanced fighters like the Lockheed P-38 Lightning, the Grumman F6F Hellcat, and the Vought F4U Corsair, which were not only more powerful and robust aircraft, but were built in numbers the Japanese could not hope to match, the Zero lost the advantage. The Japanese fighter still held an edge in maneuverability, but American pilots generally knew better than to get suckered into a turning contest and made the most of their superior speed, ruggedness, and firepower.

The Zero became a second-rate fighter. To make matters much worse, combat attrition was steadily eliminating the Japanese Navy's best pilots, and the Japanese could not provide adequate training to the needed volume of replacements. Japanese pilots, once experienced and confident, were becoming second-rate as well, and increasingly outmatched by Allied pilots who had learned the trade the hard way, as well as increasingly effective anti-aircraft fire.


The Japanese aircraft industry attempted to design and produce improved fighters to replace the Zero, but Japan simply did not have the engineering and manufacturing capability to keep pace. The Japanese had no choice but to keep on building Zero fighters. Attempts to improve the type's performance didn't work out.

Two "A6M4s" were converted from A6M2s by fitting them with a turbocharged Sakae engine, but the new engine could not be made to work reliably and the A6M4 was abandoned. In fact, some air historians have wondered if there ever was an A6M4 in the first place. The Japanese tend to avoid use of the number 4, since in Japanese it can be spoken as "shi", which also means "death", making the number unlucky. Skipping a designation such as A6M4 would have a definite basis, but postwar examination of records showed that the variant did actually exist.

* A more modest update, the "A6M5" or "Model 52", began life as an A6M3 with new wings to permit faster dives, featuring a thicker skin and rounded, non-folding wingtips, as well as a new exhaust system that provided a slight amount of additional speed from exhaust thrust. The A6M5, or "Type 0 Carrier Fighter Model 52", went into production in the fall of 1943, and demonstrated a noticeable improvement in performance.

Two sub-variants followed. The "A6M5a", or "Model 52a", had even thicker wing skinning, and cannon with belt feed instead of drum feed in the wings. The belt feed allowed the ammunition for the cannons to be increased from 100 to 125 RPG.

The "A6M5b", or "Model 52b", incorporated an armor glass windscreen and a fuel-tank fire extinguisher to reduce the aircraft's inclination to immediately burst into flames when hit. The A6M5b also replaced one of the 7.7-millimeter guns in the cowling with a 13.2-millimeter Type 3 machine gun, a license-built Browning.

The "A6M5C" or "Model 52c" added armor plate and larger fuel tanks with self-sealing, and featured one 13.2-millimeter gun in the cowling, plus a 20-millimeter and 13.2-millimeter gun in each wing, for a total of five guns. The A6M5c first flew in September 1944. The A6M5 series machines were the most heavily produced Zero variants, with at least 5,000 built.

The A6M5c was just an interim fit until the more powerful Sakae 31A engine, which featured water-methanol power boost, was ready for service. The first Zero with such an uprated engine, the "A6M6c" or "Model 53c", performed its initial flight in November 1944. It was similar to the A6M5c except for the new engine and self-sealing wing tanks. Production was performed by Nakajima. The Sakae 31A engine provided noticeably improved performance, when it worked properly, but under the pressures of war Japanese manufacturing quality was in steep decline.


* By this time the Zero's most important mission was Kamikaze suicide attack, with the aircraft fitted with a 250-kilogram (550-pound) bomb for attacks on Allied vessels. Although many Kamikazes were shot down, many got through American defenses and inflicted great damage on US Navy warships. Zeroes were also used for home defense against American bomber raids, and apparently some A6M5s were field-modified with a single upward-firing 20-millimeter cannon to operate as ineffectual night fighters.

Mitsubishi did manage to design two final variants of the Zero. The first was the "A6M7" or "Model 63", which had the Sakae 31a engine and five-gun armament, and could carry a 500-kilogram (1,100-pound) or a 250-kilogram (550-pound) bomb under the centerline, along with two underwing tanks. It first flew in May 1945, and was intended for the attack or Kamikaze role.


The second was the "A6M8", which was to be fitted with a Mitsubishi Kinsei 62 engine with 1,000 kW (1,340 HP), giving it a top speed of almost 575 KPH (360 MPH). Ironically, Horikoshi had wanted to use the Kinsei engine from the beginning, but the IJN had regarded it as too powerful. The larger engine dictated elimination of the 13.2-millimeter gun mounted in the cowling, with the four guns in the wings retained, and an improved fuel-tank fire extinguishing system was fitted. Two new-build prototypes were flown in the summer of 1945, but by that time it was a case of "much too little and far too late." It did not enter production before the war ended in August, after almost 10,500 Zeroes of all types had been produced.


Mitsubishi A6M Rei-sen (Zero)

Authored By: Dan Alex | Last Edited: 05/09/2021 | Content ©www.MilitaryFactory.com | The following text is exclusive to this site.

The Mitsubishi A6M "Rei-sen" was the primary naval fighter of the Japanese Empire heading into World War 2. The aircraft was recognized by its pilots as the "Zero-sen" based on the Imperial Year calendar (1940 at the time). The Allies eventually adopted the "Zero" name as the type's nickname while the official Allied codename for the became "Zeke". The A6M received much attention in the early stages of the war in the Pacific where it became the first naval aircraft to be able to best any of its land-based counterparts through a combination of speed, maneuverability and range. Mitsubishi Heavy Industries of Japan produced some 10,939 examples from 1940 on. The series survived the whole of the war up to the Japanese surrender of September 1945, its worth having been proven over five years of conflict.

Origins of the A6M lay in pre-war 1937 by which time Mitsubishi had just delivered the A5M. The A5M was a monoplane fighter developed for the Imperial Japanese Navy and incorporated a streamlined fuselage, low, forward-set monoplane wings and a single-seat cockpit. While 1,094 of the type were taken into inventory, the type still held some old-fashioned design elements which rendered it an obsolete-appearing aircraft by World War 2 standards. It held an open-air cockpit for the pilot with a raised fuselage spine and fixed, spatted main landing gear legs. Visibility out of the cockpit was poor and armament centered on a pair of 7.7mm Type 89 series machine guns.

With these limitations in mine, the Imperial Japanese Navy pushed both Mitsubishi and Nakajima for a new carrier-borne naval fighter of greater capability - particularly range to prove important over the vast spans of Pacific Ocean in the upcoming Japanese campaign. Also, the hitting power of the aircraft was to be improved by implementation of cannon armament coupled to machine guns for a formidable one-two punch. Due to the space on Japanese carriers, the aircraft would also have to be relatively compact and feature folding wing assemblies for storage. The IJN sought particular specifications out of their new mount: a maximum speed of 310 miles per hour and a climb rate of 9,850 feet reached in 3.5 minutes.

Nakajima engineers eventually found the requirements too restrictive and did not submit a formal design, leaving Mitsubishi to head the project. Their design (attributed to Jiro Horikoshi) became a smoothly contoured monoplane wing fighter with a fully-enclosed cockpit and wholly retractable landing gear legs. The engine was fitted to a compartment at the front of the fuselage in the usual way and the wings sat ahead of midships. Visibility was slightly improved over that as found on the A5M as the fuselage spine was lowered into the fuselage shape. The canopy was of greenhouse style and still provided for adequate situational awareness for the pilot. The wingtips could fold upwards for a reduced wingspan in storage. One of the qualities of the Mitsubishi design that would prove both good and bad was its lack of armoring for the major components of the aircraft - cockpit, engine and fuel tanks (as well as self-sealing fuel tanks). While the lack of this armor protection made for a lighter, and therefore more agile, aircraft, it decidedly reduced the survivability of both crewman and airframe in a fight against equal or superior fighters. The Mitsubishi design was also an excellent turning machine, which gave it an edge against contemporaries for a time. Armament was a mix offering of 2 x 20mm cannons in the wings and 2 x 7.7mm machine guns in the engine cowling. Power was from a Nakajima radial piston engine driving a three-bladed propeller.

The initial prototype was unveiled on March 16th, 1939 and achieved first flight on April 1st of that year. On September 14th, the aircraft was officially adopted by the IJN as its new standardized carrier-based fighter mount. Initial aircraft were powered by a Mitsubishi engine (Zuisei line) until a decided shift was made towards a Nakajima product. The Mitsubishi aircraft was adopted as the A6M "Zero-sen" Type 00 Fighter and saw its first service in July of 1940 against the Chinese. It quickly proved itself the finest fighter in the world and bested nearly all opponents in the Asian and Pacific theaters and certainly alerted observers in Washington, D.C. and elsewhere but nothing was done to further investigate the type.

Production of A6Ms eventually eclipsed all other Japanese aircraft of the war. Mitsubishi was its maker but additional manufacture was handled through competitor Nakajima who produced over 6,200 examples alone. Additional production was seen from Hitachi and Sasebo and included a floatplane derivative which also saw extensive service in the war.

By the time of the Japanese surprise attack on Pearl Harbor, Hawaii, on December 7th, 1941, the IJN managed a stable of some 400 Zero fighters and the carrier groups to field them. Zeros took part in the devastating attacks which rendered many USN warships useless or damaged and thrust the United States into a formal war declaration against the Empire of Japan. From there on, the A6M was fielded in all major Japanese campaigns and retained its air dominance heading into 1942 and 2 x 132lb bombs were added for the ground strike role. The aircraft now deserved the respect of Washington observers and its capabilities were fully noticed.

It was not until the middle of 1942 that the Allies managed to capture an intact A6M and study it from the inside out back in the United States. It was from this work that the weaknesses of the Mitsubishi aircraft were soon discovered and new counter tactics arranged for Allied pilots. The lack of armoring proved a critical design flaw in the Zero and Allied pilots would work at exploiting this fatal flaw. Additionally, the United States Navy was now turning to more modern, capable fighting mounts in their F6F Hellcats and F4U Corsairs replacing outgoing frontline types like the F4F Wildcats. The turning point in the early stages of the Pacific war then came at the Battle of Midway in June of 1942 where these new American fighters squared off against incoming waves of Zeros and earned a tremendous victory in the process. The Americans benefitted from armoring of critical components, improved weaponry and tactics and increased performance from dominant engines. Against this, the Zero had now met its official match.

From 1943 onwards, the Zero proved a far lesser, more vulnerable foe than seen in the early stages of the war. A "definitive" Zero was produced as the A6M8 which incorporated a Nakajima Kinsei engine of 1,560 horsepower but the arrival of this variant proved a moot addition. Tide had shifted away from the Japanese Empire and for the Allies and territorial losses mounted into 1945. The Zero was eventually relegated as a carrier for suicidal airmen in the kamikaze strikes that followed. These were outfitted with 1 x 550lb bombs for maximum carnage.

Operators beyond the Imperial Japanese Navy were few and included Thailand. Post-war use was seen by China (Republic of China) and Indonesia. Several airframes exist in flyable form today and many have survived as museum showpieces. Some have had screen time in several motion pictures to date.


Mitsubishi A6M Zero Fighter

Few American fighter pilots on their own survived a turning, twisting, close-in dogfight against a capable Japanese pilot flying a Mitsubishi A6M Zero during World War II. Innovative tactics devised by U.S. Navy Commander John S. “Jimmy” Thach in 1942 returned the advantage to American pilots but the Zero remained a deadly adversary until the war ended. The Japanese official designation was Rei Shiki Sento Ki (Type 0 Fighter). Type 0 referred to the year of the emperor’s reign when production of Zero fighters began in 2600 on the imperial calendar (Julian calendar year 1940). Pilots called it the Zero even after the official codename became ‘Zeke’ in 1942. In this blog, I will explore why the Zero remained one of the world’s most maneuverable fighters to the end of the war.

Zero chief designer Jiro Horikoshi assembled a team in 1937 to design a new fighter for the Imperial Japanese Navy with two primary goals in mind: to make the aircraft as maneuverable as possible and to provide it with enough range to escort Japanese bombers all the way to distant targets in China and back. Navy leadership set these requirements based on missions against Chinese targets during the Second Sino-Japanese War that began in July of that year. When Horikoshi and his team began working on the aircraft in October, they already knew that making the fighter as lightweight as possible would benefit both maneuverability and range.

Making the Zero Lightweight

Horikoshi’s team designed lightness into the Zero’s airframe by paying close attention to many small details. As explained in a 1945 article about the Zero published in Aviation, “Nothing has been spared to keep weight down, neither excessive man-hours to manufacture complex units nor increasing maintenance difficulties for ground crews.” An example is the bracket made of sheet aluminum pierced with large lightening holes and riveted together to support the aileron control tube. Crafts persons could have made this subassembly more easily using fewer and larger metal pieces, but at the cost of increased weight. Workers cut lightening holes in many parts, and in several areas they used plywood instead of aluminum or steel as backing to reinforce the metal canopy frame and to reinforce the false spar that supported the ailerons and flaps in the wings.

For heavier solid parts of the airframe, the team used “extra super duralumin,” which was developed in 1935 by Sumitomo Metal. By alloying zinc with aluminum, metallurgists made a strong lightweight metal that resisted fatigue. Horikoshi used it to build solid pieces such as the two main wing spars that brace the wing much like the keel braces a ship. The Alcoa company began using a similar aluminum alloy in 1943 called “7075.”

Airplanes are built in subassemblies. Wings, fuselage, tail, engine, and landing gear follow separate paths around a factory before workers join them together during final assembly. The fittings that attach the wings and fuselage together are strong and heavy. To make these parts smaller and reduce their weight, Horikoshi’s team permanently joined the wings to the Zero fuselage and designed the aft fuselage including the tail to more easily mount to the forward fuselage at a point just behind the cockpit. Each wing half-mounted the guns, the landing gear, and the fuel tanks, making the wings significantly heavier than the tail. The fittings needed to join the tail could be smaller and lighter because they only had to support the weight of the tail. The gross weight of the A6M2 Zero (5,555 lb.) was 1,871 lbs less than its primary adversary in spring 1942, the Grumman F4F-4 Wildcat (7,426 lb.).

Making the Zero Maneuverable

Locating the engine close to the cockpit didn’t just save weight, it made the Zero more maneuverable as well., The centers of gravity and the aerodynamic center of lift lie at points very near the cockpit and serve as the fulcrum through which the empennage acts as a lever. Keeping the engine close to the fulcrum allowed the aft fuselage to be shorter and save a bit more weight. The elevator retained enough leverage to push the Zero into a tight turn or loop when the pilot hauled back the stick.Wing loading, the weight supported by each square foot of an aircraft’s wing in level flight, also impacts maneuverability. Less wing loading generally means quicker maneuvering because there is less inertia to overcome when the pilot moves the controls to pitch, roll, and yaw the aircraft. At 24.3 lb/ft², the A6M2 Zero had a lower wing loading than the Grumman F4F-4 Wildcat at 28.6 lb/ft². The Zero design team used an engine that made around 300 horsepower less than the Pratt & Whitney R-1840 Twin Wasp powering the F4F-4 Wildcat. Newer American fighters more than doubled the Zero’s horsepower with a commensurate increase in wing loading and performance. The American pilots refused to attack Zeros unless they held a clear advantage in height or speed. When they did attack, they made one pass and hopefully “boomed” a Zero and continued right on going past, avoiding a dogfight. Once they were out of range, they regained the altitude or speed advantage and attacked again if possible and necessary, again one pass, boom, zoom away at speed or to regain altitude above the target.

Accounts of fighter operations during the Pacific war vary on how often Zeros carried radios. All the Zeros flying during the Midway operation in June 1942 had them, but whether a Zero had a radio or not varied depending on the operational needs of a particular mission. Those Zeros not equipped with radios would have been tens of pounds lighter with a corresponding slight decrease in wing loading. The Japanese were slow to develop and use self-sealing fuel tanks but eventually did so later in the war. That they did not begin the war with self-sealing tanks and armor plate to protect the pilot was a result of several factors including an intense and pervasive focus on offensive operations driven by strategic necessity and cultural inclination. The absence of this protective equipment was less costly at the start of the war and even contributed to the Zero’s agility in combat, but American tactics and technology rapidly improved and the Japanese eventually lost many pilots flying Zeros that lacked this protection.

With the extra fuel from a droppable tank carried on the belly, a Zero could fly over 1,600 miles, more than 300 miles farther than the F4F-4 carrying two drop tanks. As the war continued, weight increases due to armor and self-sealing fuel tanks reduced the Zero’s impressive flight range. All the characteristics that comprise the aircraft design process such as structures, aerodynamics, propulsion, and accommodation, act in unison. Changes to one usually affect the other. Horikoshi’s team successfully balanced these characteristics to make the Zero as light as possible and highly maneuverable. As the war progressed, the Zero continued to operate without significant improvements, suggesting that Horikoshi’s team had already extracted all possible performance from the Zero design.

U. S. Navy sailors have tied down Japanese aircraft from the Pacific theater to the deck of the escort aircraft carrier USS Copahee as it sails toward the West Coast. The ship may have carried the National Air and Space Museum’s Zero, one of twelve found on Saipan Island. The forward deck elevator is lowered into the hangar deck.

Russell Lee is a curator in the Aeronautics Department and responsible for Japanese aircraft.


Icons of Aviation History: The Mitsubishi A6M Zero

The Mitsubishi A6M Zero fighter is one of the most famous aircraft of the Second World War. For several years, it dominated the skies over the Pacific. But, like the island nation that built it, the Zero was unable to keep up with the industrial power and technological advances of its opponents.

A6M5 Zero on display at the Smithsonian Air and Space Museum

The first aircraft carriers had been built by Britain in the last years of the First World War. The United States followed during the 1920’s. But the tiny island of Japan, who held dreams of forming an empire in east Asia, became the most enthusiastic proponent of naval air power, and built one of the largest carrier fleets in the world.

In 1937, Japan had been locked in a war with China for several years, and had already conquered most of the coastal areas. The Japanese Navy had just introduced a new fighter plane, the Mitsubishi A5M Type 96, a low-wing monoplane with fixed landing gear which was given the code name “Claude” by American intelligence. The Claude quickly established itself as a nimble fighter, capable of taking out anything the Chinese could put in the sky–including American and British designs.

But Japan had bigger ambitions and was already planning for new military conquests–either a move against the Soviet Union into Siberia, or a thrust into southeast Asia to sieze the Dutch, British and American possessions there. Either move would, the Japanese knew, bring war with the British and American fleets, and that would require a fighter plane even better than the Claude.

So just a few months after the A5M took to the skies, the Japanese Navy released specifications for a new fighter to replace it, to be known as the A6M. The new plane had to have a speed of 310mph at 13,000 feet, it had to be capable of climbing to 9800 feet in 3.5 minutes, and it had to be able to fly for 6-8 hours at cruising speed, and a minimum 2 hours on normal power. Finally, it had to be at least as maneuverable as the Claude and carry the same armament–two .30-caliber machine guns and two 20mm cannon. It was a performance standard that no plane in the world at that time could match.

The Nakajima company kicked around some preliminary designs, but decided that such a plane was simply impossible with current technology. A design team at the Mitsubishi company, however, led by Jiro Horikoshi, concluded that these standards could be met, but only if the plane were exceptionally lightweight. Horikoshi’s design therefore took every possible opportunity to save weight. The fixed landing gear of the Claude was replaced by retractable gear. The A6M’s skin would be made from a new lightweight aluminum alloy. A smaller air-cooled radial engine, the Zuisei-13, would be used to drive a two-bladed propeller. And, to save more weight, the plane would have no armor plating to protect the pilot even the gas tanks would have their self-sealing rubber coatings dropped from the design.

Two prototypes were completed in 1939. The test flights revealed some problems with vibration, so the two-blade prop was replaced with a three-blade, and the Mitsubishi Zuisei engine was replaced by the slightly more powerful Sakae-12, which was manufactured by the Nakajima company. The resulting aircraft was designated the Mitsubishi A6M2, and was adopted by the Japanese Navy as the Type Zero Carrier Fighter, or Reisen. The Allies gave it the codename “Zeke”, but it was always known to British and American pilots as the Zero.

The Zero had been developed in complete secrecy, and when it first appeared in the skies over China in 1940, it was a total surprise. The British and Americans, in a fit of silly racism, had dismissed the Japanese as nearsighted inferiors who could neither build nor fly a credible airplane. The Zero demonstrated how wrong they were. Not only were the Japanese Navy pilots some of the best-trained in the world, but their Zero fighter could outmaneuver anything else in the sky. The first Zero squadron in China shot down 99 Allied planes with the loss of only two of their own. One flight of 27 Soviet-built fighters had been completely destroyed. When Claire Chennault, commander of the American “Flying Tiger” volunteers in China, sent reports to the US describing the performance of the new Japanese fighter, American intelligence simply did not believe him, concluding that such an airplane could not exist. The Japanese Navy, meanwhile, ordered both the Mitsubishi and Nakajima companies to begin manufacturing carrier-based Zeros.

A6M2 Zero, on display at the US Air Force Museum, Dayton OH

By the time the Japanese launched their carrier attack on Pearl Harbor in December 1941, they considered the Zero fighter to be the combat equivalent of at least 4 or 5 Allied P-35, P-39 or P-40s. Although the Imperial Japanese Navy carriers had over 400 A6M2 Zeros available, they elected to use less than 100 of them in the attack, figuring that would be enough to handle the entire American fighter force in Hawaii. In the event, nearly all the American fighters were destroyed on the ground, and only 8 Zeros were lost in the raid, mostly to anti-aircraft fire.

Over the next six months, the Zero established unquestioned Japanese air superiority. In the Philippines and the Dutch East Indies, the A6M2 took on everything from Brewster Buffalos to British Hurricanes. At Coral Sea, it demonstrated its dogfighting superiority to the US Navy F4F Wildcat. By the middle of 1942, however, the Americans began to develop effective tactics to deal with the Zero, by exploiting the plane’s weaknesses and avoiding its strengths. Chennault’s P-40s in China found that they could fly above the Zeros, dive down on them to make a rapid pass, then continue diving to run away and climb back up for another pass. The Navy adopted the “Thach Weave”, in which a pair of Wildcats would fly back and forth to cover each other’s tails.

In June 1942, the Japanese Navy lost four carriers and hundreds of planes and pilots at Midway, a blow which crippled it for the rest of the war. During the battle, a Zero fighter crash-landed in one of the Aleutian Islands and was found by the Americans, giving them their first close look at the fabled fighter. Within months, new fighters like the F6F Hellcat and F4U Corsair appeared, which were specifically designed to beat the Zero. Although the Japanese made some improvements in the A6M5 model, and designed a number of very capable fighter planes to replace the Zero, their inferior industrial base was never able to keep up with the war’s demands, especially after B-29s began their systematic bombing campaign. Though outclassed, the Zero remained in production until the end of the war, with almost 11,000 built in various models–over half of these by the Nakajima company. Its final role was as the favored plane for kamikaze suicide attacks on American carriers.

Nearly all of the remaining Japanese Zeros were destroyed by the occupying Allies after the end of the war. Today only a little over a dozen survive, many of them being crashed airplanes that were recovered and restored.

In April 1944, US Marines captured a group of 12 intact A6M5 Zeros on Saipan. They were shipped back to the US for technical evaluation. One of them was sent to the Navy test facility at Eglin, Florida, for evaluation flights, then to Wright Airfield in Dayton, Ohio. In 1974 the Zero was restored by the Smithsonian, painted in the markings of the 261st Naval Air Corps stationed at Saipan, and is now on display at the Air and Space Museum.


Operational History

The first A6M2, Model 11 Zeros, arrived in China in early 1940 and quickly proved themselves as the best fighters in the conflict. Fitted with a 950 horsepower Nakajima Sakae 12 engine, the Zero swept Chinese opposition from the skies. With the new engine, the aircraft exceeded its design specifications. A new version with folding wingtips, the A6M2 (Model 21) was pushed into production for carrier use.

For much of World War II, the Model 21 was the version of the Zero that was encountered by Allied aviators. A superior dogfighter to the early Allied fighters, the Zero was able to out-maneuver its opposition. To combat this, Allied pilots developed specific tactics for dealing with the aircraft. These included the "Thach Weave," which required two Allied pilots working in tandem, and the "Boom-and-Zoom," which saw Allied pilots fighting on the dive or climb. In both cases, the Allies benefited from the Zero's complete lack of protection, as a single burst of fire was generally enough to down the aircraft.

This contrasted with Allied fighters, such as the P-40 Warhawk and F4F Wildcat, which were extremely rugged and difficult to bring down, though less maneuverable. Nevertheless, the Zero was responsible for destroying at least 1,550 American aircraft between 1941 and 1945. Never substantially updated or replaced, the Zero remained the Imperial Japanese Navy's primary fighter throughout the war. With the arrival of new Allied fighters, such as the F6F Hellcat and F4U Corsair, the Zero was quickly eclipsed. Faced with superior opposition and a dwindling supply of trained pilots, the Zero saw its kill ratio drop from 1:1 to over 1:10.

During the course of the war, over 11,000 A6M Zeros were produced. While Japan was the only nation to employ the aircraft on a large scale, several captured Zeros were used by the newly proclaimed Republic of Indonesia during the Indonesian National Revolution (1945-1949).


Watch the video: Только История: Mitsubishi A6M Zero (August 2022).