What engine powered the Schwimmwagen Type 166?

The Schwimmwagen Type 166 was powered by a 1.1 L flat-four engine.

Its air-cooled, four-cylinder boxer engine displaced 1,131 cc and produced about 25 horsepower. The layout was closely related to the engine used in the civilian KdF-Wagen—the vehicle that became better known as the Volkswagen Beetle—and the military Type 82 Kübelwagen.

Porsche designed the amphibious car for German military use during World War II. Its watertight hull, four-wheel drive and rear-mounted folding propeller let it travel on roads, rough ground and water. The propeller was driven directly from the engine’s crankshaft, while the front wheels helped steer afloat.

A common mix-up is confusing the engine’s displacement with its power: the engine was about 1.1 litres, not a 1.1-horsepower unit. The Type 166 entered production in 1941, and 15,584 were built through 1944, making it the most-produced amphibious car in history.