Lu
You say that in fwd flight,in a (normal) helicopter, the A/C flys to the position of the cyclic ie push the cyclic straight fwd and the A/C will follow.That in a robbo because of the 18 degree off set you must position the cyclic to the right. You are incorrect.
You have forgotten about a phenomena called inflow roll. As a helicopter accelerates fwd,we must progressively tilt the disc fwd. Now in straight and level flight, the induced relative airflow gives the tilted disc a greater angle of attack at the front, than the rear. The result because of gyroscopic precession is a slight roll to the right. So in (normal) helicopters, in straight and level fwd flight the cyclic position is actually fwd and slightly left.
Perhaps this explains the design of the 18 degree offset on the robbo. Next time I fly one I will take note of the actual stick position.
Secondly,the important thing in a low "G" situation is to avoid mast bump,(as rotorque pointed out) so it does not matter if the disc is slightly off centre as long as contact with with the mast is avoided. A neutral cyclic position will ensure this.
Thirdly, cyclic position during lift off is irrelevant.If a student or inexperienced pilot where to sit there making sure the cyclic is exactly neutral, whilst raising the collective, he/she will never achieve a smooth lift off. In any helicopter.If taking off with even the slightest X wind or sloping ground the cyclic must be positioned into wind/up hill in order to achieve a vertical lift off. The technique is to LOOK FWD,slowly raise the collective, make pedal adjustments to keep the A/C straight as you become light on the skids and compensate for drift with the cyclic. (fore and aft as well as laterally)
I can assure you that unless conditions are dead still, the ground is dead level and the helicopter is perfectly balanced under the mast, the stick will never be in the middle. Further more if you sit there watching it you will probably tip over or run into something.
Fourthly, after the head has been off or the controls are re-rigged, a flat pitch and/or autorotation rpm check will quickly reveal any rigging errors.
You made no reference to side slipping/out of balance flight in your last post. I take it you concede my point!