Originally Posted by
Fly Aiprt
A variation on the bicycle theme :
To allow Boeing to stick to the mechanical trim, why do they not gear the manual trim wheels ? In the hub, or with some sort of derailleur since there seems to be some chain linkage ?
If I were Boeing, I'd have been studying such solutions for months now.
Of course that means admitting the manual trim is unmovable in certain trim/speed combinations, but everyone already knows that.
And no doubt serious Airworthiness agencies will mention the point.
As I mentioned above a ratcheting handle could provide up to 3X torque for the pilot inputs assuming the handle was full diameter and folded out at the edge, goes from 0.5 diameter to 1.5X diameter. This is simpler than switchable gearingn needed since it is too slow already.
BTW The envisioned handle would be 'inline' with the wheel, not sticking out to side like the current one, once extended the wheel could be moved with a quick back and forth motion of the handle.
Don't think we know what the actual force requirement are under the assumed conditions.