Re: Connecting Wings to Fuselage - Question

From:         Ross Monroe <rocnroll@u.washington.edu>
Organization: University of Washington
Date:         05 May 95 03:27:13 
References:   1
Followups:    1
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On 1 May 1995, JOSEPH PETER UHLARIK JR wrote:

> Occasionally I have seen press reports about the progress on a new airplane
> in which the milestone of joining the wings to the fuselage is mentioned.
> Over the years, it appears that it is common that the fit is not exact.
> Is the mechanical connection done with bolts going through holes? If there
> is a mismatch, what is the method used to allow the wing to be joined.
> I know that they do not go out and build another wing.   ;-)
>
> Are holes enlarged? Are new holes drilled? Does anyone have any idea
> how large the mismatches are if measured in inches, for example?
> Why should such mismatches occur and not be designed out in the first
> place?

It is true that a "perfect" fit is never really achieved.  On the Boeing
models (I imagine that the others are the same), the wings are attached
by sliding the completed wing into the wing center section.  (The wings
are made in 3 sections; left, right, and center.)  The sections are then
"jostled" around until the proper geometry is achieved.  The bolt holes are
then drilled and the bolts are installed.  Consequently the wings are
not interchangable, but the proper hole pattern is easily achieved. (But
how often are wings changed once they are in service.)

-Ross Monroe