ORIGINAL: jetpack
I have a couple of Berkeley Models Ducted Fan models from the '50's that show this control. Its called a Stanzel's monoline. A solid wire led to the model that turned a coil of wire which moved the elevator rod back and forth. Looks almost like a heavy clockspring, with the rudder wire riding inside it, like a spiral gear.
Jetpack,
That is very interesting. I remember the Berkeley Ducted Fan planes as being free flight. I did not know they adapted them to monoline. In addition to the general actuating unit you describe, they had one that was essentially a pin driven by a worm gear that was used for speed.
One of the problems of monoline use (if my observations are correct) is that the wire twists, in addition to turning. If you observe Dale or his son flying stunt with monoline, you will occasionally see them spin the button to re-center it in the middle of the control handle. It is quick and easy to adjust and is done during level flight, between maneuvers.
The handle in question here may not have means to re-center, assuming that is also necessary for speed flight.
Note these are merely observations, I have never flown monoline.
Oh, another point. The problem with using the early Stanzel handle with FAI speed, if I remember correctly, was that no part of a person could be in front of the pylon yoke. This was to prevent whipping.
George