Pendulux Powerplant Wall ClockSolid cast and polished aluminum and brass. First developed in1904 for aircraft use, the radial engine became one of the most reliable means of power for aircraft from the First World War through the 2nd, and is still in use around the world today. An array of air cooled cylinders always an odd number from as few as 3 up to as many as 9 operated the crankshaft that turned the propeller. Charles Lindbergh used a radial engine in the Spirit of St. Louis