Re: 757 jitter

From:         jeromed@goodnet.com (Jerome Dawson)
Organization: DocuMedia Technology, Inc.
Date:         16 Feb 96 04:33:18 
References:   1 2
Followups:    1 2
Next article
View raw article
  or MIME structure

>> Has anyone noticed that if you sit aft of the wings in a 757, when the
>> aircraft makes a maneuver, there is a slight "jitter" from side to
>> side?  It doesn't happen on 737s, nor 747s.
>
*****

This bit of "dutch roll" felt in the aft area of the cabin is very common
on large airliners and it certainly does happen on both the 737 and 747.
The 747, in fact, is famous for being able to rock you to sleep in the
aft cabin. I've watched the level of water in a glass gently swirl around
below the rim as the tail "did its thing".

The phenomenon is less noticable in the 737 but becomes more pronounced
as the plane is loaded more aft heavy or at high gross weights. My guess
would be that the damping effect of the tail surfaces gets a bit less
effective as the center of gravity moves aft. Not a lot, mind you --
nothing to worry about -- but, riding in the aft cabin of a full 737, you
can feel those little side-to-side kicks and shimmies from time to time,
particularly as the plane is banked into turns on departure and approach.

Jerome