Impressive.
Where is the motor which moves the neutral position?
Aha…
The motor is driving the rotating screw which moves the point of bungee attachment - simple and clever.
It’s a pity that no yoke manufacturer produces a yoke with mechanical or simple motor driven trim 
Probably because non-pilots are not used to the real world trim operation and no sim directly supports external mechanical trimming (trim controls will not move in the sim, unless some very clever programming would be applied).
As the first test I went to the extreme. To avoid the unrealistic always-return-to-the-same-neutral-position of spring/bungee cord loaded yokes, I disconnected the pitch bungee altogether.
So now I can fly more like the real life, by operating the elevator via yoke inputs without the need for the unrealistic apply-the-trim-and-smulataneously-go-back-with-the-yoke-to-always-the-same-neutral-position.
I know this is unrealistic in the other way (very weak forces on the elevator control) but I will see how it works in the sim. I would expect issues with applying backward pressure during a turn and the releasing it for straight-and-level.
But I expect it to be better versus the common wrong behaviour of sim pilots of controlling the elevator via trim inputs instead of yoke movements. Trim should be only used to cancel the forces on the yoke, not for actually controlling the plane.
There is still some resistance (I will consider how to increase it) on the pitch axis due to mechanical drag inside the yoke mechanism. To have bit better balancing of pitch and roll axis I replaced the roll bungee with a much weaker rubber band.
So far I’m rather happy with this mod (no pitch centering spring, very gentle roll centering spring).
First impression:
Pros:
- The yoke no longer fights against me! Suddenly it became precise control instrument.
- I can keep the yoke neutral for any airspeed, desired pitch angle.
- I can apply precise pitch changes, minimal control inputs and keep them easily.
- I can fly level despite power changes.
- I can flare and touch down like never before.
Neither pros nor cons:
- It requires very gentle touch. I remember my first flight lessons in not so perfect weather - I was literally squeezing the juice from the left yoke handle, next day my left hand muscle ached. My instructor spotted this and asked to keep the yoke with just two fingers - there are not so big forces required in small GA plane, unless the weather is really severe.
- It requires constant observation of the horizon to keep the plane level or at the desired pitch angle for climb or descent. But this is also what we do in the real VFR flight. When simming I prefer to be as involved as possible, I always fly manually, so I actually like this behavior.
Cons:
- There is no trim applicable altogether. No forces perceived. The yoke stays in any position I want it. I can’t trim by feel. I can apply trim artificially, and then move the yoke accordingly, but this has nothing in common with the realism. On the other hand, the default simulator trim behavior is plainly wrong - when applying the trim, the yoke should remain in position, only the forces should disappear. In the sim with unmodified sping-loaded yoke you must move it to it’s mechanical neutral position while trimming which is just wrong!
- Aircraft should be controlled by applying pressures to the controls not by moving the controls. When you apply the pressure the control (yoke) moves, but your muscle memory should be trained for pressures not movements. With no spring on the pitch axis, I’m actually controlling the plane by moving the controls, as without the spring there are no control pressures.
- To stay level during the turn I can’t just apply back pressure and release it when the turn ends. I have to control the straight and level more visually than kinetically, by observing the horizon line position vs. the cowling. But unless you have advanced moving platform, the whole simming experience is visual, lacking the flying-by-the-seat-of-your-pants experience.
For now I’m happy with this super simple 5 min. mod and my new collaborative, precise yoke. But I will still think if/how the yoke could be modified for the movable neutral pitch position.
