Bo,

Old radio,

Pattern was "war" so I did use "military specifications" (LOL)

The circuit diagram is of the Simprop 2 + 1, an older transmitter of Simprop.
I do show the inside and you can read the diagram as easy as the written version.
The circuit board layout is of my own design to fit it in place. I did add two channels.

Working,

Start pulses generated each 20 msec by the a stable multivibrator, each channel an own one shot to generate time pulses depending of position of the stick or switch 1 - 2 msec, needle pulses are generated with each one shot on the rail to trigger the mono stable multivibrator on top to switch off the carrier wave for 0,05 msec with each needle pulse to generate the HF pulse train.

Below you see the 4 position flap selector, preselected with restrictors.
Antenna connector is visible on top connected with the pi filter circuit. (Rusty)

These are Simprop Sticks and respected for the simplicity, one potentiometer for stick and trim, we did turn the potentiometer casing with the trim lever.

Reliable as result of using lowest amount of components.

Cees