A slug of aluminum was machined with index holes. A spring and nut keep the index knob captive on the shaft. The shaft is installed to a thick plate with an index pin under the seat mounting. Pulling out on the knob and rotating it to the next index hole sets the trim.
The cords attach to coil pull-springs that are attached to the moving plate on the control stick.
A small amount of slack allows a position with no bias and as such there is no trim or any effect on the controls at all. Most of the time I use this position as my Chinook is well balanced and trimmed nicely.
Taking a passenger in the Chinook affects trim very little, and this is another great feature of the Chinook design. Changes in throttle won't effect the trim, and the craft just wants to hold altitude.
