A group in Japan has been trying to establish a museum about Japan’s military. They’ve been gathering parts and equipment that may some day be displayed in its halls. One such example is a rare Mitsubishi V12 tank engine that’s about to undergo restoration.
Built by Mitsubishi Heavy Industries, the SA12200VD is an air-cooled diesel V12 that powered the Mitsubishi Type 97 Chi-Ha medium tank. The engine is not particularly special, making 170 horsepower and somewhere between 600 and 650 lb-ft of torque. Not only was the Type 97 the most manufactured Japanese medium tank of World War II, it was also used on the Asian mainland in the second Sino-Japanese War and the Battles of Khalkhin Gol against the USSR. The photo above was taken at the Museum of the Great Patriotic War in Russia (photo credit, Mike1979 Russia).
It’s estimated that over 1100 were produced, less than 30 Type 97 tanks (including Chi-Ha and other variants) are known to have survived. Most were either destroyed in battle or scrapped to recycle the valuable steel after the war. This particular engine was returned to Japan by the US Navy.
In addition to the Mitsubishi engine, the museum will also display two other tank engines. The first is a Kobe Steel A6120VDe air-cooled diesel inline-six. Though designed for the Type 95 tank, it’s believed that this engine was never installed in a tank. It was donated by the Internal Combustion Engine Laboratory at Kyushu University, where it was believed to have spent its life as teaching material.
The third engine is a Continental R975 nine-cylinder radial engine used in early versions of the M4 Sherman, the main medium tank used by the US during World War II. This particular example has never been installed in a tank and was donated by a collector.
The Association for the Creation of a Defense Technology Museum has been working to establish a permanent gallery of military equipment since 2011. Their stated goal is to preserve the machinery for future generations. The Mitsubishi V12 will be on display publicly as is this weekend, May 2-3, before it undergoes a full restoration to working order.
I always wondered how those radial aircraft engines wound up in tanks. They are very finicky. Without careful prep before starting, they’ll blow a jug (cylinder) clean off the engine from being mounted vertically causing hydraulic lock of remaining oil in the bottom cylinders. Aircraft fastener torque figures are crazy low compared to automotive.
Early in the VW development program while it was still privately funded (possibly so early it was still the Weimar Republic), Porsche experimented with both 3- and 5-cylinder radial engines and found they had significant disadvantages in automotive use, not least of which was the vulnerable position of the bottom cylinder.