The Murphy Builders Site

Hi Mike,

Here are a couple notes and pictures of my cabin roof work in case
anything
here might be helpful. Note the liberal tape usage to hold things down
before drilling holes.
http://mae.ucdavis.edu/ransom/Murphy/20 ... 2/0802.htm

I'm not sure I even read other advice about holding off putting in the
rear
wing attach brackets, but I wasn't brave enough to do it before wing
rigging
(which I've still not done). I did however, stack up the brackets,
sandwhiched them between the two bulkheads and made careful placement
measurements so that I could cut the slots for them to stick out of
Fus-27.
This allowed me to finish off the rear "float fix doubler bulletin" in
that area,
and basically, it's all ready for final bracket hole drilling when I
eventually get
to wing rigging.
Cheers,
-Ben, 496R

On 3/5/2010 12:53 AM, mikeh wrote to Rebel builders:

Hi all,
Hoping to promote some discussion which might help enliven things on
the site and help some builders........... like me.
I have the cabin roof in place, drilled and cleco'd to the top carry
through FUS 3 only. I need to do some aligning of bulkhead and root rib
flanges to make a nice job of it. Possibly joggling the bulkhead flanges
at
the root rib will help.
I'm sure I'll sort it out but has anyone any advise that might
assist?
I'd be grateful. Any comments on the cabin roof generally would also be
gratefully received.
A bit further on is fitting the rear wing attach brackets,
sandwiched
between two bulkheads. There has been discussion in the past about

leaving

the positioning of the brackets until the wing is being fitted so the
angle
of incidence can be set correctly. This makes sense to me. Does anyone

have

a comment on this?
Cheers and thanks, keep up the good work Mike

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Saw a note in your link refering to countersunk rivets not being as strong
as domed rivets. That is true however, dimpled flush rivets (where they can
be used) are as strong or stronger than domed rivets.

Bob.

They may be as strong but they will rip out of .020 sheet much easier
than the dome rivets. Wayne has seen the results and I have confirmed
what happens with testing. I use them happily in most situations though.
Ken

Bob Palmer wrote:

Saw a note in your link refering to countersunk rivets not being as strong
as domed rivets. That is true however, dimpled flush rivets (where they

be used) are as strong or stronger than domed rivets.

Bob.

Makes me wonder if solid flush rivets might rip out of dimpled 020 just as
easily as Avex CS rivets (again, dimpled 020). I really don't want to go
there. IIRC, the AVEX to solid conversion chart supplied by MAM (and
probably originally by AVEX) gave concern only to meet or exceed sheer
strength for whatever the stacked thickness of pieces being riveted. I.E.,
didn't address the issue of thickness of that top skin per se.

I'd like to say I won't lose any sleep over it, but then testing on a
sample
does start to seem like a reasonable idea.
-Ben

On 3/9/2010 3:52 AM, klehman@albedo.net wrote to rebel-builders:

They may be as strong but they will rip out of .020 sheet much easier
than the dome rivets. Wayne has seen the results and I have confirmed
what happens with testing. I use them happily in most situations though.
Ken

Bob Palmer wrote:

Saw a note in your link refering to countersunk rivets not being as

strong

as domed rivets. That is true however, dimpled flush rivets (where they

can

be used) are as strong or stronger than domed rivets.

Bob.

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Ben,

With regards to strength: Machined CS vs Dimpled holes for flush rivets.
The dimpled holes will be stronger than the machined holes.

Hope that makes you sleep a little better. But then again, there are
minimum thicknesses of material to Machine CS a hole and that is also
dependent on which rivet you are using, 100* or 120*. Dimpling a hole is
usually done because material is too thin to Machine CS.

Cheers,
Jeff



On Tue, Mar 9, 2010 at 3:37 PM, <bransom@dcsol.com> wrote:

Makes me wonder if solid flush rivets might rip out of dimpled 020 just
as
easily as Avex CS rivets (again, dimpled 020). I really don't want to go
there. IIRC, the AVEX to solid conversion chart supplied by MAM (and
probably originally by AVEX) gave concern only to meet or exceed sheer
strength for whatever the stacked thickness of pieces being riveted.
I.E.,
didn't address the issue of thickness of that top skin per se.

I'd like to say I won't lose any sleep over it, but then testing on a
sample
does start to seem like a reasonable idea.
-Ben

On 3/9/2010 3:52 AM, klehman@albedo.net wrote to rebel-builders:

They may be as strong but they will rip out of .020 sheet much easier
than the dome rivets. Wayne has seen the results and I have confirmed
what happens with testing. I use them happily in most situations
though.
Ken

Bob Palmer wrote:

strong

can

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