photo #6180983

Here's an engine rarely seen since they were intended to be disposable. This is the 4 cylinder radial engine from a WWII German G7A torpedo. It ran on Decaline fuel (decahydronaphthalene), which was first burned using compressed air (stored in a tank onboard) as an oxidizer. The combustion byproducts were then passed through a device called a 'wet heater', which also introduced water (from a 57L storage tank) to produce superheated steam. This high pressure mixture of superheated steam and compressed air was finally sent through the engine to drive the pistons. Since the entire internal combustion/steam generator system was self-contained inside the hull of the torpedo, it could run underwater. The 4 cylinder, 'X' type radial engine produced up to 350 horsepower at its maximum power setting, which was enough to push the 26' (just over 7 meters) torpedo (the length of a large Uhaul moving van here in the States for comparison purposes) along at nearly 50mph while submerged. Interesting piece of history-and worth remembering-in my opinion.