Mono Line was around in the 50's and eversince I guess. It was made by Victor Stanzel if I remember correctly. The only places I saw it used was in the speed classes.

The handle was made like a Yankee screw driver and there were two handle parts. A fixed one at the rear and one that slide back and forth. To slide the one back and forth caused the line to twist. There was a mechanism in the plane to convert this twisting motion into uup and down on the elevator.

The line was two or three times thicker than one of the two line types.

It didn't work so well for stunt.

Jim