The last hot air engine

German immigrant Louis Kessler of Chicago was apparently quite familiar with hot air engines in his homeland. The engines his various companies manufactured were American copies of German Heinrici engines but with the addition of air cooling, making them much more portable (and practical) than the water-cooled Heinricis. While more successful with his other business ventures, Kessler wouldn’t give up on hot air engines and was the force behind several successive companies making them from about 1912 into the mid-1930s. His “Kessler Motor & Engineering Co.” made one of the last commercial hot air engines in the 1930s before its inevitable bankruptcy. Both engines in the video are shown operating with their original kerosene burners and appear more or less as they did when they left the factory. The “Duplex Vacuum Motor Co.” engine is dated 1921 and was owned by one of the company’s stockholders who was also Kessler’s next-door neighbor in Chicago.