Originally Posted by
Aluminium shuffler
From misd-agin:
"The 767 and 777 are more roll sensitive than the smaller jets. Not completely sure why. Friends have talked about it but we're not sure if it's a fuselage flex issue (ie wings move fractionally before the fuselage which attempts to 'catch up'), the size of the engines creating a greater mass that is offset from the roll C.G., or perhaps a gyroscopic effective from the large N1's? We don't know. But we do know the w/b a/c tend to have a bit of a sideways 'lurching' or 'bump' if you make large, or rapid, opposing roll inputs. The 777 in particular gets a sideways bumping motion (hate to say this but it's probably the easiest way to explain... similar to braless lateral motion...). More than the 767 it requires a slight pause before changing the roll rate request or reversing the roll request.
The 727, 767, and 777, to my recollection more than the 737 and 757, get a wing dropping sensation if large roll inputs are made. At larger roll control inputs the roll spoilers start deploying and with large inputs it literally feels like the wing is falling as opposed to rolling. And the typical reaction, sometimes called 'startle reflex(?)', is to counter-act that roll input with a large roll command to the other side, to correct the drop/roll, and the 'drop' is now done to the other side. And the over-correction starts towards the first roll direction, and back and forth it goes. If you feel that look at the wing. If you see large spoiler movements that is some of the motion. It could also be caused by gusting/shifting winds. And if you're in a 777 and feel a slight sideways lurching movement, look at the ailerons and see if they're going up and down. If they are you've found the source of the motion. It's not uncommon to feel it on the 777. So it that sense I'd agree, you can't fly a 777 like a 757/767. It will exposure less than smooth control inputs while the 767, and especially the 757, aren't quite as roll sensitive."
The 73's flight controls are manual cable and pulley affairs with hydraulic assistance, rather than all out power controls, so I suspect that is why they are relatively small and have less authority than on other types - so that they can be used in manual reversion with no hydraulics without being so heavy as to be unmoveable. The same may apply to the 727, but I don't know that aircraft's systems.
To be honest with you, I found both the 727 and 737 to be more roll sensitive in turbulence and remember using quick jabs of aileron input to counteract turbulence induced roll. The 747 was definitely more of a lumbering aircraft and less responsive. While my 777 experience is limited at this point, it is more sensitive than the 747 and I was definitely overcontrolling it in the sim which was said to be more sensitive due to the fly by wire system. On the line, I have had some daytime heating thermal type approaches and with small inputs have had no problems.