At the time of the Pearl Harbor attack in 1941, the Japanese Zero fighter could outfight anything the US could put into the sky, and Japan enjoyed unquestioned air superiority. But while the US soon produced a number of new aircraft designs, including the F6F Hellcat and the F4U Corsair, Japan, with its limited industrial abilities, continued to rely on the Zero. As a result, Japan lost its air superiority, and in 1944, at the air battle over the Marianas (known by US pilots as “The Great Turkey Shoot”) the US destroyed virtually the entire fleet of Japanese carrier aircraft. If Japan were to regain the ability to wage war in the air, it would need a radically new and superior aircraft design. The result was the Nakajima “Kikka” (“Orange Blossom”) jet fighter.
Both Germany and England had done work on jet engines before the war, and by 1941 the Germans were making test flights of what would become the Me-262. In 1944, just before the Me-262 became operational, the Japanese military attache in Berlin saw a test flight, and the Japanese military, recognizing the value of the jet fighter, asked the Nakajima company to produce their own version. The new airplane would be known as the Kikka.
Japan had done some work on jet engines, but they were far behind the Germans. The best engine the Japanese had in development in 1944 was the Tsu-11, a “thermojet” engine that used a small four-cylinder piston engine to run a compressor and ignited the fuel/compressed-air mixture for thrust. It was not powerful enough to drive a jet fighter, and was instead slated to power the newer versions of the Ohka suicide rocket plane. To power the planned Kikka, the Japanese began working on a turbojet engine design of their own, and produced the Kugisho Ne-12, but it too proved to be unsatisfactory.
The German Me-262 had been originally designed to use the BMW 109-003 turbojet engine, but when that engine was delayed by engineering and production problems, the Me-262 was switched to use the bigger and heavier Junkers Jumo 004 turbojet instead. In 1944, Japan managed to obtain some photos of the original German BMW 003 engine and a cutaway drawing of its internal workings, and using that as their basis, Japanese engineers were, amazingly, able to produce their own similar design, which became known as the Kugisho Ne-20. The Ne-20 produced a thrust of just over 1,000 lbs. By 1945, the new engine was ready for production.
With the availability of the Ne-20 engine, the design for the Kikka jet fighter was finalized. Superficially similar in appearance to the German Me-262, it was a twin-engine fighter with foldable wings, intended to be stored in caves and tunnels to protect it from American air attacks. Unlike the swept-wing German design, the Kikka had straight wings. The Kikka was also armed with two 30mm cannons instead of the Me-262’s four. With its smaller and less-powerful engines, the Kikka had a top speed of 433 mph, compared to the Me-262’s 560 mph.
Only one protoype of the Kikka was completed. On August 7, 1945, the day after Hiroshima, the Kikka prototype made its first test flight. Four days later, it was fitted with small rocket motors to shorten the takeoff distance, but the plane accidentally ran off the end of the runway and was damaged. Japan surrendered shortly later.
After the war ended, the Americans found about 50 Ne-20 engines and 20 or so Kikka airframes in various stages of production, and took several examples back to the US for testing. Today, only one Kikka survives, a test specimen from a US Navy base in Maryland, and only three Ne-20 engines survive–two in the Smithsonian and one in Japan.
The Smithsonian’s Udvar-Hazy Center is currently in the process of restoring the sole remaining Kikka for display.