There are many styles of cruise controls, but what I'm going to present here is simple to use and construct. I have used this cruise control on my PPG for several years with great success. Total cost is under a buck!
Although it is simple, it will not work on every throttle handle. A lot throttles use the bicycle brake-handle type of construction, and this control works on that type.
The materials needed for the project are a large pink eraser and a zip tie. Cut the eraser diagonally as shown and drill a hole at the large end to accommodate the zip tie. Run the zip tie through the hole and attach to your handle near the throttle pivot point. I used an eraser because it has the right friction to hold it in place when inserted between the lever and bracket.
It is self explanatory, but I'll go through the steps. Open the throttle to the desired position, insert the eraser wedge with the non-throttle hand, and release the handle. To release the throttle, simply open it slightly, and the wedge will fall out. I adjust the rpm while flying with one hand; simply push the wedge against the riser until the engine is running at the desired rpm. If the eraser falls off for some reason, don't worry, it won't damage the propeller.
If you have questions or comments, my email is: