Their focus is on free piston engines as power sources for hybrid electric vehicles, something which due to their small size they seem ideally suited for. Perhaps the free piston engine has faced ...

Technically speaking, the portion of the piston that's missing is small, but it doesn't take much to kill an engine. Per the video, it appears the cylinder was running hot enough to melt the piston.

The choices of single-engine piston aircraft range from small, two-seat light sport airplanes for purely affordable recreational flying to high-end luxury models, with price tags to match.