Bourke is to engines as Tesla is to alternators, this was no accident, Robert Bourke taught engine maintenance at the Unites States Air Service School at Kelly Field, Texas in 1918. He fully understood the theoretical limitations of the Otto 4 cycle and sought a simpler design and for years worked on the problem until 1932 when he built a working prototype. Bourke set out to overcome the complex design of gasoline engines, he succeeded. The Army Air Force was impressed and awarded him a contract to build an aviation prototype. According to legend he did and connected a wooden prop to the crank, when he gunned the engine the torque was so great the prop sheered, the blades could not keep up with the engine RPM acceleration.
Read more @ The Bourke Engine Could Revolutionize Private Aviation | Veterans Today
My question why isn't anyone using these?