The rotary engine makes a comeback for cars and drones as gasoline gains popularity as a complement to electric motors.

When it comes to unique engine designs, one of the most prolific is the trusty rotary configuration. Instead of featuring a number of spherical cylinders moving up and down like in most internal ...

The engine in question was the Wankel rotary, named after German engineer Felix Wankel, who first patented the concept in 1929. Instead of pistons moving back and forth, the rotary engine used a ...