Fuel Cutoff
Dubro #255 super smoker fuel line pinch off with lever for servo activation.
Ukie combat pinch offs usually made by cottage industry and are operated by centrifugal force levered weights that operates in event of a linecut flyaway.
422 Quarter forty pylon racers with mostly Nelson engines and no air cutoff or throttle usually use a home made affair that is just a piece of wire attached to the servo output arm and through a washer or wire ring. It has a hook on the end that grabs the fuel line. When activated the hook pulls the fuel line through the loop and pinchs off the line.
John