On December 7, 1941, the Japanese A6M Zero Model 21 manufactured by Mitsubishi was one of the most iconic participants in the attack on Pearl Harbor. While the bombers inflicted the bulk of the damage, the Zero fighter planes kept the American forces at bay, strafing battleship decks and airfields to maximize the deadly efficiency of the attack.

Going into World War II, the Zero was a feared fighter, dominating the skies regardless of what the Allies threw at it. In the early months, it was believed that the A6M Zero scored a kill ratio of 12 to 1. No matter how hard Allied pilots tried, the Japanese warplane always seemed to outmaneuver any of their current craft.

Let’s take a closer look at this legendary aircraft.

The Mitsubishi A6M Zero Fighter

A6M Zero planes aboard <em>Shokaku</em> preparing to attack Pearl Harbor, 7 December 1941

A6M Zero planes aboard Shokaku preparing to attack Pearl Harbor, 7 December 1941

Entering into service in July of 1940, the A6M Zero was built as a long-range fighter by the Mitsubishi Aircraft Company. It didn’t take long after the new fighter took to the skies to realize that Japan had manufactured one of the most efficient aircraft ever. To make it even deadlier, the Zero was equipped with two powerful 20mm cannons, two 7.7mm machine guns, and two 30 or 60 kg bombs.

Following very specific design specifications that dictated speed, climb, and range, Mitsubishi turned to a new aluminum alloy known as “extra super duralumin.” The new material made the Zero lighter, which helped it exceed the maneuverability of the older A5M fighter and gave it the longest range of any single-engine fighter in World War II.

Though the A6M Zero was considered to have the best maneuverability of any aircraft in the Pacific at the outset of the war, it still suffered from several design shortcomings. At speeds above 180 mph, its ability to turn and adjust course was greatly limited, and its top speeds, which averaged around 332 mph (345 mph with the engine’s emergency overboost), were considered modest when compared to other fighters. Still, the Zero had little competition during the early years of the war and, when the Allied pilots first encountered the Zero, they were reportedly shocked as to how efficiently and quickly it could move.

With such a powerful aircraft, one may think that Japan should have been able to rule the Pacific skies for years, but as the Zero’s designer, Jiro Horikoshi, explained, “Even the best fighters become obsolete within two years during times of war.” And that, essentially, is what happened to Japan’s fearsome fighter. Though the Allies could do little but watch as the Zero devastated their aircraft in the first few months of the war, by mid-1942, Horikoshi’s design had begun to grow obsolete. Then, the Allies stepped forward with their own means of controlling the skies.

The Zero Meets Its Match

In the opening months of the War in the Pacific, the A6M Zero was unquestionably the best fighter aircraft in the sky, but it was also being put up against antiquated aircraft that couldn’t match the more modern design of Mitsubishi’s fighter. Japan was ahead of the times with Horikoshi’s design, but when the United States introduced the Grumman F6F Hellcat, the “extra super duralumin” suddenly wasn’t enough to maintain the Zero’s dominance.

Grumman F6F Hellcats in flight

Grumman F6F Hellcats in flight

Designed to be the counter to the A6M Zero, the F6F Hellcat quickly became the dominant fighter in the Pacific Theater. Design of the Hellcat was overseen by Lieutenant Commander Butch O’Hare and Lieutenant Commander A. M. Jackson from the Navy’s Bureau of Aeronautics (BuAer), and was guided by comparisons with the Zero. Using data from combat with the Japanese fighter, the designers determined that the Hellcat needed to be powered by an 18-cylinder Pratt & Whitney R-2800 Double Wasp radial engine and a three-bladed propeller from Hamilton Standard.

Unlike the A6M Zero, the F6F was designed to be able to withstand damage, which meant installing bullet-resistant windshields and additional armor protecting the oil tank and cooler. The weight of the Hellcat exceeded that of the Zero by approximately 5,600 lbs, but it still proved to be faster than the Japanese model. The A6M did still out-maneuver the Hellcat, but durability and speed were enough to turn the tide of the aerial war. Trial reports that pitted a Hellcat prototype against an A6M5 model warned pilots not to “dogfight with a Zero” but instead focus on using the “superior power and high speed performance to engage at the most favourable moment.”

After the introduction of the Hellcat, the Zero couldn’t rule the skies as it did, and Japan was never able to match the innovation it showed with the A6M. Despite developing multiple models, Japan’s superiority in the air started to falter by mid-1942, making it difficult for them to regain their footing and produce a counter to Grumman’s F6F Hellcat.

Visiting the Zero

One of the few remaining Mitsubishi A6M Zero fighters is on display at the Pacific Aviation Museum, on Ford Island at Pearl Harbor. Although its paint scheme is identical to the plane that crash landed on the island of Niihau after the Pearl Harbor attack, this particular craft fought in the Solomon Islands in 1943.

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