Hi! Tony.
IMHO don't force the cockpit module to fit down precisely. Be sure the
"lower fuselage moulding" is adequately supported and suitably braced for
the width dimension to fit the cockpit module. Then have a dummy run and
mark out where the cockpit module will sit in a relaxed state. Remove it
then overturn it and have one person apply a redux bead to all its surfaces
that will contact the inside of the fuselage. Another person also applies a
thick redux bead to the fuselage ready to receive the cockpit module making
sure that there are gaps where the tufnol control bearings will be located
(you will have a "bad hair day" if when it has all cured you can't move the
controls!)
then carefully turn over the module and lower it into place allowing the
excess redux beads to squidge out from between the two surfaces.
I wouldn't apply any undue pressure anywhere other than to ensure there is
contact of the redux between all necessary surfaces. This is best observed
by shining a strong light underneath the fuselage which clearly shows where
there isn't redux contact. Trowel off all excess redux and use the excess to
trowel it into any gaps.
This way you won't have any outside filler to apply and fill dimples which
the application of screws or pop rivets cause. It's obvious that a little
more redux will be used but at least it has structural strength where the
addition of filler adds only the weight and can flake off later .
You shouldn't get any cockpit module distortion which would be likely to
make the controls tight.
Also make sure that the aileron control arms clear the fuselage bottom for
their full travel range.
Regards
Bob Harrison G-PTAG
----- Original Message -----
From: "Tony Renshaw" <tonyrenshaw@optusnet.com.au>
Subject: Europa-List: Firewall Cutout before module bonding
<tonyrenshaw@optusnet.com.au>
>
> Gidday,
> I am considering cutting out the firewall so that I can see what is doing
> on when I drop my module in for the last time, onto the blue glue. When I
> push down on the module it at the firewall end, it sits lower, but my
cross
> bracing pulls on the attachments on the head rest. Also, the whole seat
pan
> moves up and down as I load and unload the front of the module, with
weight
> bearing down. So, I reckon I have done about the best job of stabilising
my
> module for my flight controls, and fear that this force to make the module
> sit down might in fact put a longitudinal axis banana into my module and
> this might be felt in the control circuit. So, I intend on leaving it
> alone, and I suppose the gaps between module and fuse can be addressed in
> several ways. I can use screws, to pull the fuse up to meet the module but
> I hesitate because it seems to me that you create a perforated line of
> weakness in the fuse skin at key locations. I don't really like the
> dimpling potential, so I reckon I am more inclined to either fill the 2-3
> mm gap in places with either redux or maybe a 2-3-4 ply bid layup in the
> lower areas before bonding. This would require a whole lot of accuracy to
> work out where 2,3, or 4 plies were required, so I reckon the answer is
the
> redux. I think at worst I could add maybe 1/2 kg of redux. Big deal I say,
> because I'd prefer to lose it off my middle, which could spare 1/2 kg. The
> addition of redux would be offset by the addition of filler on the outside
> of the fuse if I pull it into place. So, less work but nominally more
> weight I hope. Oh, someone mentioned cutting off the footwell floor
> sections of the module and applying bid patches to replace them later. Is
> this still the recommended way to get it in, for a single handed, or maybe
> 1 helper installation?? I note when pushing down on the rudder floor
> vertical flange that the force distorts the side of the module, so I am
> going to stabilise the module at this lower end to preserve my gear mount
> attachment dims. If anyone has any suggestions at this stage, with module
> insertion impending, I'd really like to hear from you.
>
> Reg
> Tony Renshaw
> Sydney Australia
>
> Classic 236 B.B. Taildragger
> Tail, Wings, Ailerons, Flaps Complete and Connected
> Lower Fuse in Jig, Tail Torque Tube installed
> Mass Balance assembly installed and deflections sorted
> Roof Panel between doors completed.
> Photos at:
>
http://forum.okhuijsen.org/modules.php?set_albumName=TonyR&op=modload&name=gallery&file=index&include=view_album.php&PHPSESSID=902b69917a45f8b18ac84fe3f85a704b
> Intended Engine: 912S CS prop (model undecided)
> Instrumentation: Undecided
>
>
|