The following Technic sets
- 8043 (Motorized excavator)
- 42009 (Mobile crane)
- 42082 (Rough terrain crane)
- 42110 (Liebherr)
and likely a couple of more have a double set of linear actuators to move the boom.
For all these models, rotation is administered simultaneously on the gears of the linear actuators through bevel gears that are symmetrically placed.
I've been told that the symmetrical placement of the bevel gears is problematic. The reasoning being that as the boom moves up or down, additional rotation is placed on the linear actuator gears, but in opposite direction, causing one LA to slightly retract while the other to slightly extend, causing torsion on the boom. Hence it would be better to place the bevel gears asymmetrical.
- Is the reasoning wrong? (I think not)
- If the reasoning is correct, why are the Lego designers seemingly not aware of this and haven't they addressed this in later Technic sets ?