The engine with no pistons. In 1957, engineer Felix Wankel did the unthinkable. He built a working rotary engine that had no pistons at all. Instead of cylinders firing up and down, it used a spinning triangle inside an oval chamber to generate continuous power with fewer parts and smoother motion. Mazda was the only car maker crazy enough to mass produce it, and they turned it into the RX-7, a lightweight sports car with a tiny engine that revved like a motorcycle. At just 1.3 liters, the Wanke

An In-Depth Look at the Mazda Rx-7 Wankel Engine | Engineering Explained