Flightplan

The Imperial Japanese Navy began planning for a long range, lightweight, carrier borne fighter in May, 1937, issuing specifications of 2 - 7.7mm MG, 2 - 20mm cannon, 132 pounds bombs and state of art radio gear.   The specs were so aggressive that only two firms responded to the call for bids, Nakajima and Mitsubishi.   After a short time, Nakajima decided the specs were impossible and dropped out of the competition.  However, Mitsubishi assigned Jiro Horikoshi the job of designing the new fighter which would become the famous A6M series, known to the Allies as the “Zeke” and to most as the Zero.

Some people have attempted to infer that this was a copy of a Howard Hughes racing plane that disappeared on a flight over the Pacific in 1935 but it was, in fact, an original design by Horikoshi and his team.  The prototype was fitted with a Mitsubishi Zuisei 13 engine with 780 hp, top speed of 305 mph, which was below the specified top speed, but the plane was otherwise satisfactory.  The second prototype exploded during flight in October, 1939 but a third was flown in January, 1940, with the designation “A6M2”.  This series was fitted with a Nakajima NK1C Sakae 12 radial with 925 hp, giving a top speed of 332 mph, more than specification.   This became the Imperial Japanese Navy (IJN) carrier-borne fighter launched against Pearl Harbor and was the basis for all future Zekes.  Nakajima also built a float plane version designated the A6M2-N and called “Rufe” by the Allies.

The Zero was constructed from a new aluminum alloy called Extra-Super Duraluminum (ESD) except for the rudder and elevators, which were fabric covered.  It was fitted with a 3 blade variable pitch Hamilton-Standard type propellor built by Sumitomo.  The sliding canopy afforded 360 degree visibility for the pilot and a radio-direction finding antenna enabled the pilot to fly long-distances over water and jungle.  An external fuel tank could be carried on the centerline, giving the plane a range of 1,195 miles.

Mitsubishi also made a variant of the A6M2 with folding wingtips, the Model 21, to allow better storage aboard carriers.   The Model 21 was followed by a major new variant, the A6M3, with a new engine two-speed supercharger, wider propeller, increased ammo supply for the cannons, and clipped wing with no folding wingtips.  The A6M3 was difficult to distinguish from the A6M2.

When the Pacific War began, there were 328 Zeroes operational.  The IJN felt with good reason that they had a superior fighter while some IJN pilots thought them invincible.  Japanese Intelligence considered one Zero to be worth 3 to 5 Allied aircraft.  As the Japanese struck Pearl Harbor and swept toward Southeast Asia, over the Philipines, into the South Pacific and across the Central Pacific, the Zero proved a complete shock to the Allies, overwhelming all aerial resistance.  Although General Chennault had sent reports to the US from China about the Zero during 1940, they had been filed and forgotten.

Actually, the brass thought Chennault was exaggerating the capabilities of the plane to make his AVG reports seem much better.  Though the IJN was certain they had a war-winner in the Zero, they were pleasantly surprised at it's initial performances against Allied aircraft during the first six months of the war.   Allied planes could not cope with the Zero's speed, maneuverability and firepower.  Any Allied pilot attempting to dogfight the Zero was quickly sent spinning to his doom.

Chennault's reports from China had advised against just such an attempt and promoted a tactic of gaining altitude on the Zero, diving through their formations, shooting down as many as possible, zooming and repeating.  The Curtiss P-40, with which the AVG was equipped, could out-dive and outrun the Zero in the dive.  This tactic proved to be useful for most Allied aircraft throughout the war but it took six months for the Navy to accept it.

The Allies were thoroughly intimidated by the Zero.  Although the Grumman F4F Wildcat was inferior to the Zero in maneuverability, and in almost all aspects of performance, it could easily take ten times more punishment than the Zero and could escape the Zeke by diving away.  After suffering a nasty learning curve, the U.S. Navy and Marine Wildcat pilots learned tactics to allow them to more or less hold their own against the Zero.

On 4 June 1942 the Japanese launched an air raid against the Aleutian Islands as part of "Operation Midway".   One of the Zeros that attacked Dutch Harbor was hit by ground fire that cut an oil or coolant line, forcing the pilot, 19 year old Flight Petty Officer Tadayoshi Koga, to make an emergency landing on the island of Akutan, which had been designated for emergency landings.  Koga thought the ground was a meadow but, in fact, proved to be a bog.   Believing he was landing in a meadow, he let down his gear and attempted a wheel landing but the bog flipped the plane on it's back, killing the pilot.  The almost intact wreckage of DI-108 was found on 10 July 42 by a PBY on routine patrol.  The wreckage was retrieved, sent to San Diego, repaired and test flown to learn it's strengths and weaknesses.  It was then flown in mock dogfights against various US aircraft and both defensive and offensive tactics developed.  Fighter pilots passing through San Diego for the Pacific were allowed to fly the plane for familiarization and to pass information about it to the fleet.  Weaknesses found included the Zero's controls becoming "heavy" at high speeds. They also found the plane to roll easily to the left but difficult to roll to the right, and the Zero tended to stall during negative-gee maneuvers due to the float-type carburetor.

Allied pilots were advised to bob up then down when a Zero was on his six, stalling the Zero's engine momentarily while the Allied plane would roll right.  A Japanese writer, Masatake Okumiya, author of the book “ZERO”, claimed that the loss of Koga's Zero was no less serious than the defeat at Midway.

As the war progressed, the introduction of advanced American fighter types such as the P-38 Lightning, F6F Hellcat and F4U Corsair, which were not only more robust and powerful aircraft but were built in numbers the Japanese could not hope to match, the Zero lost it's advantage.

The Japanese fighter still held an edge in maneuverability but U.S. pilots knew better than to get into a turning contest and made the most of their superior speed, ruggedness and firepower.  The Zero became a second-rate fighter and to make matters 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, and increasingly outmatched by Allied pilots who had learned the trade the hard way.

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 producing the Zero fighters.  Attempts to improve the type's performance didn't work out.  Two “A6M4s” were converted from A6M2s by fitting them with a turbosupercharged Sakae engine but the new engine couldn't be made to work reliably and the A6M4 was abandoned.  A more modest update, the A6M5 or Model 52 began as an A6M3 with new wings to permit faster dives, featuring thicker skins and rounded, non-folding wingtips as well as a new exhaust system that provided a slight 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 performance improvement.  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 an increase of ammunition from 100 rounds to 125 RPG.

The AS6M5b or Model 52b added an armored glass windscreen and a fuel-tank fire extinguisher to reduce the aircraft's inclination to burst into flames when hit.  The A6M5b also replaced one of the 7.7mm cowl guns with a 13.2mm Type 3 MG, a license-built Browning.

The A6M5c was an interim fix until the more powerful Sakae 31A engine, with water-methanol power-boost, was ready for service.  The first Zero with this engine, the A6M6c or Model 53c, performed it's maiden flight in November 1944.  Production was by Nakajima.  The Sakae 31A engine provided noticeably improved performance when it worked properly but Japanese manufacturing quality was suffering under pressure of war and was in steep decline.  By this time, the Zero's most important mission was Kamikaze suicide attack with the plane fitted with a 550 pound bomb for attacks on American vessels.  Although the kamakazi did sink many ships and kill many US sailors, they were ineffective at stopping the US offensive drive to the Japanese homeland.  We can only guess at their effectiveness against an invasion fleet off Honshu or Hokkaido.

"Fat Man" and "Little Boy" intervened and the Japanese surrendered on 14 August , 1945 and signed the formal surrender documents on 2 September, 1945, aboard the battleship, USS Missouri, in Tokyo Bay.  Admiral Halsey issued orders to his AA gunners to shoot down any renegade Japanese fliers who may try to disrupt the proceedings “in a friendly fashion”.

Many high ranking US fliers flew captured Zeros, reportedly including Colonel Charles Lindbergh.  The Extra Super Duraluminum used in the construction of the Zero had a marked tendency to crystallize, especially when exposed to salt air, and, consequently few original Zeros now exist.  Those that do exist have had most of the ESD removed and a different alloy (6061-T6?) applied in it's place.

Now...   the "rest of the story" about Koga's A6M2 Zero, DI-108:

In February, 1945, while the DI-108 was being taxied, a Curtiss SB2C Helldiver overran it, chewing it apart almost to the cockpit and it was scrapped.  The SB2C deserved it's nicknames, the Beast and SOB, 2d class.

There are about 16 authentic Japanese Zero-Sen aircraft left around the world today and very few are flyable.   Twenty-five Zero replicas were built from AT-6 "Texans" for the movie "Tora Tora Tora" but the number still flyable today is unknown.  These replicas were also used in the television show "Baa Baa Black Sheep".

The Japanese philosophy concerning combat aircraft resulted in the IJA and IJN pilots going to war in a plane that was actually little removed from the crates flown in World War One.  It was faster, fabricated of metals, had a more powerful engine and radio BUT there was the same amount of protection for the pilot as in a British BE-2 from WWI:  NONE!   A single incendiary round in the tank resulted in a fire and explosion while the fifty cal MG could cut the plane in two.

One more tidbit:  The Imperial Japanese Army aircraft were painted green and most, but not all, had fixed gear whereas the Imperial Japanese Navy aircraft were painted light gray and most, but not all, had retractable gear.  Both used the Zero throughout the war.

Now, the British “Zero”:

In the late 1930's, the British firm "Gloster" designed, built and flew a fighter that looked remarkably like a Japanese Zero.  The Zero look-alike was built in response to the British Air Ministry requirement “F.5/34” which also produced the Hawker Hurricane and the Supermarine Spitfire.  Like the Zero, the Gloster F.5/34 contender was a low-wing, all-metal monoplane with an air-cooled radial engine.  The engine was the nine-cylinder Mercury IX with 840HP.  The plane was to be armed with eight 7.7 mm Browning machine guns.  Gloster put no great effort in the design and, in fact, never gave it a name or designation other than the F.5/34 requirement code.

One prototype flew in December 1937, with a second following in March 1938.  Gloster then dropped out of the competition and filed away their work.  Performance of the Gloster F.5/34 was similar to the early model Zeros and the dimensions were extremely close to that of the Zero.  The British plane was slightly heavier, had a shorter wingspan, and longer fuselage.  Exactly how the Gloster would have compared to the Zero would take a comparative evaluation that was never performed and is now beyond useful speculation.  Although the Gloster F.5/34 flew well before the Zero, this does not imply that the Zero was a derivative of a British plane.  The F.5/34 was an obscure airplane and it is unlikely that the Japanese knew much about it and the two planes were different in details.   For more information concerning this airplane, Google “Gloster F.5/34” and you will find many articles about it.