----[Please read http://ercoupers.com/disclaimer.htm before following any
advice in this forum.]----

Yup, it was a trick question, but someone was on the ball!  Old Paul
Prentice asked Fred about this wing bolt torque value one day and Fred
didn't have a specific answer, except that he wouldn't put a value on it.
Ever since that we've just cranked 'em down tight and it's probably right
where the torque value is supposed to be!


----- Original Message -----
From: "Bob Saville" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, December 24, 2000 1:39 PM
Subject: Re: [COUPERS] loose wing/bolt madness


> Hi Al.
>     I can't find it in any of my manuals either. Check with an AP, he
should have the chart that I've
> seen 'somewhere' that gives torque values for each size of AN bolts. If
there isn't a specific value for
> the application (such as cyl base bolts, exhaust, etc) then I guess the
'master chart' for bolts by size
> would be the fallback rule. (Just guessing as that's about all I'm
qualified to do.)
>     Have a nice Christmas.........
>
> Bob Saville
>
> A J DeMarzo wrote:
>
> > ----[Please read http://ercoupers.com/disclaimer.htm before following
any advice in this forum.]----
> >
> > Here's a good question that has had the N. Texas Coupe Group stunned
for
> > years:  Where, in any of the manuals, does it state the torque values
for
> > the wing bolts?  Something to look for instead of opening presents!
> >
> > Have a Great Holiday and a Safe & Happy New Year!
> > Al
> >
> > ----- Original Message -----
> > From: <[EMAIL PROTECTED]>
> > Subject: Re: [COUPERS] loose wing/bolt madness
> >
> > > The Alon parts manual calls for a standard AN bolt for the wing
attach
> > > fittings, and I think all the other models of the plane use the same
bolt.
> > > By definition, a standard AN bolt is not a close tolerance bolt - so
the
> > fit
> > > of the bolt in the wing attach fittings is not critical (within
certain
> > > limits, of course).  The wings are held tightly in place by the
torque
on
> > the
> > > bolt.  The torque on the bolt develops friction between the "plates"
of
> > the
> > > wing attach fittings.  The friction between the plates is what keeps
the
> > > wings from moving.
> > >
> > > If the holes in the wing attach fittings are worn, or if the bolts
are
> > worn,
> > > then at some point in the life of the plane, those bolts were not
torqued
> > > properly.  If they were torqued properly, the joint would have no
relative
> > > motion in it (because of the friction between the plates), and the
parts
> > > would not have been able to move causing the wear.
> > >
> > > If you hear a clunk when you lift your wing, and IF that clunk is
coming
> > from
> > > the wing attach fittings, then in all probability it is because the
bolt
> > is
> > > not properly torqued.
> > >
> > > The design and theory behind bolted joints is thoroughly discussed
in
> > > mechanical engineering text books if anyone wants to look it up.
> > >
> > > And of course.... all of this is just my opinion, so take it for
what
it's
> > > worth.  I would consult with an aeronautical engineer before I did
> > anything
> > > to change the design of the wing attach joint.  In my opinion, if
worn
> > parts
> > > are found, then they need to be replaced with factory original
parts,
not
> > > rigged with sleeves or wrapped with shims.
> > >
> > > Good Flying,
> > >
> > > Wayne DelRossi
> >
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