This episode of Real Engineering is brought to you by Brilliant, a problem solving website that teaches you to think like an engineer. In the late 19th and early 20th century the Japanese Empire was under rapid expansion, fueled by a feudal born military economy and European technology.First invading the chain of islands north and south of it’s home island, fighting a bitter war with Russia for control over Manchuria and annexing Korea all before WW1.
The outbreak of World War 1 gave Japan the perfect platform to expand further, alling against Germany and taking control of German positions in the Pacific. Making Japan the dominant power in the east Pacific, with its sphere of influence extending from the Asian mainland to the mid Pacific. To maintain this influence Japan had undergone rapid industrial expansion, growing from a technologically primitive feudal country, and developing the third largest Navy in the world, with only the United States and the British Navies challenging it. With US territory in the Philippines and Hawaii, and British territory in Malaya, Hong Kong and British Borneo, conflict was inevitable and tension in the Pacific was rapidly growing. On September 27th 1940 Japan entered an alliance with Germany and Italy, a clear warning to the Americans. Enter the war in Europe, and you will face war in the Pacific.
This warning did not come unchallenged and the United States moved it’s pacific fleet from California to Pearl Harbour in Hawaii. From here many of us are familiar with the story. Japan capitalized on this ill advised show of force and took the United States by surprise, attempting to wipe out the US Navy in the Pacific in one foul swoop. A decisive victory that announced Japan to the Western world as a force to be reckoned with. At the height of their power in WW2 Japan seized control from Western powers in China and Southeast Asia. But the war machine was doomed to failure, and was destined to over extend itself. Nothing illustrates the turning fate of the Japanese Empire like it’s iconic fighter plane the Mitsubishi A6M Zero. A plane that entered world war 2 as feared and formidable advisory for any plane in the pacific theatre, but slowly and surely lost its tactical advantage until it was finally regulated to a dispensable resource, fitted with 250 kilogram bombs and flown straight at enemy ships in a last ditch effort to protect the Empire. The Zero was a thoughtfully designed plane. Its designer Jiro Horikoshi, built upon the framework of his previous design the A5M, the world’s first carrier based monoplane.The Imperial Japanese
Army challenged Mitsubishi and Nakajima to both design and build successors to this plane to aid the war effort in China. The plane was to have a top speed of 500 km/h, be fitted with two 7.7 mm machines guns and two 20 mm cannons, incredibly heavy armaments for fighters of that era. On top of all this, it was to have an operating ceiling of 10,000 metres. Be capable of flying 2 hours at max speed, and 6 to 8 hours at cruising speed with drop tanks attached.
These were fuel tanks that could be jettisoned when empty, or when an enemy was encountered to increase maneuverability. These specifications alone were ambitious enough, but the plane also needed to be carrier based, which limited it’s wingspan to 12 metres. The specifications were so ambitious that Nakajima pulled their bid from the project, but Jiro Horikoshi persevered. His design  was ingenious. Incorporating many of the most advanced techniques of the era. Thin elliptical wings minimised drag, along with state of the art flush riveting. New heat treatment knowledge obtained from the Germans allowed Horikoshi to develop an all metal structure. It’s frame entirely made from this new age hardened aluminium and he cut holes into the frame where possible to reduce weight. All to achieve that ambitious range requirement of the Imperial Japanese Army, but that requirement forced Jiro to make some sacrifices to the planes design. Favouring speed, maneuverability and range with its lightweight construction, over heavy armoring. It’s skin was only 1.2 millimeters thick over it’s thickest sections, like the leading edge of the wing, and forward fuselage to just 0.5 mm thick at it’s thinnest over the aft sections of the plane.
While enemy outer skin thicknesses were not significantly thicker, the outer skin is intended to be a smooth aerodynamic surface not protective armouring. Typically these planes would contain thicker plate armouring over key locations like the engine, fuel tank and cockpit. The zero did not. On top of this the zero did not employ self-sealing fuel tanks, which used several layers of rubber that would swell and expand when soaked in fuel, and thus seal any holes. Weight savings even came down to the cockpit size, which was smaller than most Western designs, designed to fit the on average, shorter Japanese pilot. The zero was designed on a doctrine of training skilled pilots with nimble, lightweight planes. What use was armor if you didn’t get hit, what use was armor if you didn’t have the range to patrol your territory. The lightweight skin made it difficult to get into the plane without damaging it, so the designers incorporated footholds and handles, which sat flush to the planes surface, and could be released with a button when needed. This mechanism seen from the inside of the plane looks like a mushroom. With these rounded domes protecting an internal bag which could be inflated using a pilot controlled valve which redirected air from the front air intake, so that in the event of an crash landing into the sea the plane would not sink. The designers of this plane clearly never intended it to be used as a disposable weapon. Yet that is exactly what happened. The Japanese Air Force met little airborne resistance in China, it’s vastly more advanced planes picked the archaic chinese bi-planes out of the sky with ease. It would meet a far more formidable enemy on December 7th, 1941, when Japan attacked Pearl Harbor. The surprise attack aimed to cripple the US Navy and cement Japan as the most powerful Navy in the Pacific. A show of force to dissuade the mighty American Navy from interfering with the Empire’s domination of Asia. An ill advised attack that had the opposite effect. America entered WW2 the same day, with it two primary fighters at the time. The P-40 Warhawk, and the F4F Wildcat. Neither were as nimble as the A6M,and in early battles the Zero had a tactical advantage, despite both planes having a higher top speed. Much of this was down to the superb training of the Japanese pilots, who at the outset of the war, were among the best in the world. The Japanese focused on quality over quantity. This slowly changed over the course of the war. Skilled pilots we dying quicker than Japan could produce them, and instead Japan switched it’s training process into overdrive. Sending hundreds of green pilots to war. The final blow to the legendary plane would come when the US Navy captured an intact Zero and began probing it for weaknesses.  They soon discovered three fatal flaws that would dismantle its tactical advantage overnight. The Americans knew of the Zero’s tendency to burst into flames, due to it’s weak armouring and lack of self sealing fuel tanks. It only took a few shots to disable the plane, the trouble was getting into a position to get those shots in. With American test flights of the Zero they soon found their opening. The Zero suffered from the exact same problem as early Merlin engines, which powered British planes like the Spitfire and Hurricane, It utilized a float carburetor, which as we discovered in one of my early videos, made zero-g maneuvers impossible as it caused the float valve to open. Flooding the engine and shutting it off. Unlike the Merlin engines of the Spitfire however, the Zero’s issues were never addressed, and received little upgrades throughout the war. The last nail in the coffin for the Zero came with the discovery of it sluggish nature at high speeds, becoming much less maneuverable when maxed out, due to aerodynamic stiffening of the ailerons. Where high airspeeds made it difficult for pilots to extend the control surfaces with their simple manual lever control system with no help from hydraulics. With these characteristics in mind American pilots were trained on how to deal with the Zero. The primary rule being for Allied pilots to maintain high speed and never to try to out-maneuver a Zero at low speeds. With its tactical advantage gone, and no improvements to be seen, and Japan running short on skilled pilots The Zero was given the role of Kamikaze bomber, along with the other outdated planes of the Japanese Air Force. For an island nation at war, running short on valuable raw materials, this was a desperate last attempt at protecting the motherland. The common story retold was that these young men were brainwashed to an absolute devotion to their emperor. The living god of Japan. All too often, detail is lost by only listening to secondary sources. The stories told directly by Japanese pilots paint a different story. Letters from young pilots , like Captain Adachi Takuya, paint a picture of young men sacrificing their lives for their loved ones. Perhaps the most telling of all stories comes directly from the mouth of one of Japan’s most famous aces “Saburo Sakai” . This is a paraphrased quote from an interview before his death in 2000. “A lot of Westerners looked at the kamikaze strategy with complete shock, the idea of putting a kid in a plane and telling him to kill himself by crashing into the enemy. But even if you don’t tell him to crash into something, putting a kid with only about 20 hours flight time into a plane and telling him to take on U.S. pilots in Hellcats and Corsairs is just as much a suicidal tactic as being a kamikaze. We figured that if they’re going to die anyway, the kamikaze attack will probably cause more damage to the enemy for the same price in lives.But let me tell you, all that stuff you read about “dying for the emperor … Banzai!” that’s all crap.” It should be noted that in the same interview  Saburo denies the Rape of Nanjing ever happened, which is essentially on par with holocaust denial, so you may want to take any information from this primary source with a grain of salt. These young men were often barely trained with more than a basic understanding of flight mechanics, and many of them crashed into the sea well away from enemy ships, precisely because they never learned to deal with the Zero’s control surfaces becoming essentially useless at high speeds, like in a dive. Many of them died desperately pulling on their stick, not being able to overcome the force of air pushing the surface back down. I think it’s fair to say, these young men were not solely dying out of duty for their emperor, but for their family, their friends, for their country. Emboldened by a culture where the group takes precedence over the individual, where suicide was viewed as a reasonable and honorable choice, when faced with defeat. This wasn’t terrorism, as many western writers have stated.This was war. The most devastating Kamikaze attack on May 11th 1945, came just two months after the United States firebombed Tokyo, killing over 100,000, displacing 1 million and cutting the industrial output of the city in half. This bombing raid was more destructive than either of the nuclear bombs. With industrial output declining, raw materials scarce, trained men few and far between and their homeland under attack. This culture of self sacrifice for the country made Japan a fortress that no army wanted to invade. Made worse by President Roosevelt’s policy of unconditional surrender, which only encouraged unconditional resistance, and so two young Japanese Pilots Kiyoshi Ogawa and Seizo Yasunori, each piloting Zeros with 250 kg bombs attached flew to their death on that day. Emerging from low cloud cover the two rookie pilots began their diving attack on the aircraft carrier the USS Bunker Hill, releasing their bombs and proceeding to crash their planes straight into the flight deck. Both bombs penetrate d the flight deck and the resulting fires and explosions claimed the lives of over 390 sailors and airmen. A devastating attack, that disabled the aircraft carrier for the rest of the war, but this was a rare occurrence and the vast majority kamikaze attacks failed to hit a target. Either missing the target completely, or being intercepted by anti-aircraft fire and enemy fighters. Ultimately the Japanese were being pushed back to their native Island and the B-29s that dropped the nuclear bombs in Nagasaki and Hiroshima weren’t even escorted over Japanese land, as the Japanese Air Force had little resources to counter an attack like this. Their airforce had risen and fallen alongside their empire. I’m not going to do any smooth segue for this video, as it would just be off tone, but videos like this would not be possible without Brilliant. My goal for this project has always been to inspire the next generation of engineers. 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