What is this smoke/steam think behind the Japanese fighter planes like the Zero?
What is this smoke/steam behind the Japanese fighter planes like the Zero?
That picture is from a Movie. It's also a replica plane confuses the question. If your question is why did Japanese Fighter planes have a reputation for trailing smoke in the latter half of WWII, that's the question I answered.
Fermented sweet potatoes.
Japan imported most of it's oil during WWII. Beginning in 1944, due to the allied embargo, and the lack of oil, Japan relied on non traditional means (sweet potatos) for easing it's "acute shortage" of aviation fuel. These non traditional means of producing high octane aviation fuel produced poor quality results. That poor quality fuel is what caused the smoke signature associated with Japan's fighters when operating at high speeds (engine rpms) late in the war.
WWII Database: A6M Zero
poor Japanese fuel quality toward the end of the war also plagued the remaining Zero fighters; the fuel was so bad that the Zero fighters often emitted a thin trail of dirty smoke behind them when they were at wide-open-throttle, at times even letting out bright flashes of flames from exhaust ports (interestingly, these fuel issues sometimes led to US pilots believing they had successfully damaged the enemy, which in turn led to inflated kill scores).
U.S. Naval Technical Mission to Japan 1 November 1946
In the Summer of 1945, when the tremendous momentum of our drive was rolling up the islands of the Pacific and bringing imminent the invasion of the Japanese homeland itself, the United States Navy established a mission to determine the position of the Japanese in the field of naval technology.
Japanese Fuels and Lubricants - Article 3 Naval Research on Alcohol Fuels Feb 1946
Japanese Naval Research pertaining to the production of alcohols from various sources and the application of alcoholic aviation fuels has been investigated. This report deals primarily with the improvement of fermentation techniques, the synthesis of alcohols and the practical testing of alcoholic aviation gasoline. The program was for the most, carried out during the last year of the war and was necessitated by the acute scarcity of conventional aviation gasoline. Interesting findings include the fact that approximately one pound of ethyl alcohol could be produced by fermentation from eleven pounds of sweet potatoes and that after a year's research it ws found necessary to limit the use of ethyl alcohol fuels to training planes in view of its service performance characteristics. .
.... The alcohol program is of interest since it emphasizes the extent to which Japan was forced to rely on substitute fuels because of the scarcity of aviation gasoline. The necessity for using alcohol and other substitutes is discussed in NavTechJap Report, "Japanese Fuels and Lubricants, Article 2-Naval Research on Aviation Gasoline," Index no. X-38(N)-2"
By the spring of 1944 the shortage of hydrocarbon type aviation gasoline had become so acute that it became necessary to give immediate attention to the use of ethyl alcohol as a substitute. At that time however the supply of cane sugar and molasses from Formosa, Java, and the Philippines was decreasing, and it was found necessary to convert butanol plants to the production of ethyl alcohol; to unitize Japanese sweet potatoes and Manchurian grains as raw materials; and to install additional fermentation plants throughout Japan. Research relating to the transition from sugar and molasses to other raw materials was primarily concerned with the selection of proper nitrogen nutriments necessitated by the use of such substances as sweet potatoes and kaoliang. .
In the meantime, other laboratories were studying these and related problems. At Kyoto Imperial University, for example a survey was being made of some one hundred and fifty different varieties of sweet potatoes. The purpose of this research was to select the most suitable varieties for use as foods and as sources of alcohol, since the extensive utilization of sweet potatoes as a fuel source would seriously affect the Japanese food supply.
Aviation Gasoline Technology Transfer during the Second World War: Japan, Germany and the U.S.A.
Production of aircraft gasoline by Japan peaked in 1943, and as the command of the air and the sea were lost, import of crude oil was hindered. By 1944, they were struggling to secure enough amount of gasoline, even as they dropped the octane-value from 92 to 91. The supply route to the southern region was cut off in 1945, and the production practically stopped. The Navy adopted an American method, and produced leaded 92-octane aviation gasoline by hydro cracking light kerosene and cracked gasoline under high temperature and high pressure at the Naval Fuel Depots within the country. The Japanese refining technology was mainly dependent on hydro-cracking of kerosene and gas oils
The photo is of a Mitsubishi Zero A6M3 Type 0 Model 22 which was introduced to the Japanese fleet December 1942. A subsequent model 52 was introduced in August of 1943 with "a reworked exhaust system" which included "directing the exhaust around the fuselage, heat shields just aft of the (exhaust) stacks", and "fire extinguishers on the fuel tanks in the wings".