A clunk is a sound made by a heavy object hitting something hard. Something fell to the floor with a clunk. a loud sound made when two solid objects hit each other (From the sound)
The weighted end of the fuel line inside the model's fuel tank This keeps the flexible fuel tubing submerged in fuel regardless of the aircraft's flying position
Term used to describe the weighted end of the fuel pickup line in the fuel tank The purpose of this is to ensure that the fuel pickup is always in the fuel supply, even when inverted