Gidday,
Below is the way to put a module in, and avoid the pitfalls and anxieties I
have experienced. The problem is that the manual is written for people who
take 3 steps forwards and 1 back, which is completely discriminatory for
those of us that take 3 steps forward and 2 back. Without doubt when you
put your module in there is a couple of things you need to be told.
Firstly, the gap between module and boat needs to be identified and written
on the boat, in an area that isn't going to be covered up with glue.
Secondly, unlike me, after going to this trouble you need to take note of
this, and moreso, place enough mix so that it exudes out to that depth, not
place that much glue and when you push it down, there isn't enough
material. My anxiety is that the glue would exude into areas I wouldn't
want it, but that is "incorrect". I measured accurately gaps of 1-2 mm and
put in 1-2 mm of redux. There is only 4 areas that matter, and all the rest
is incidental weight. Now, no one argue about this until you have read the
rest of this, because I can certify, undeniably, this is an area of the
build where you shouldn't be worried about weight. So, why not worry about
weight.............................because, what is the ramification if you
don't put in enough redux? Ok, here goes. Oh, I forgot to stress point 2,
you MUST, MUST, MUST, MUST, MUST, MUST, MUST, MUST, MUST, MUST, MUST, MUST,
MUST, MUST, MUST, MUST, MUST, MUST, MUST ( do you believe me that I am
serious!!) use a bright light such as a trouble light, an incandescent bulb
on a long cord, beneath the module to show up voids. Had I known I had
voids like I do, I could have addressed the issues whilst I still had a wet
cockpit module base, and a wet boat. The problem now is that I have a dried
out boat, and a dried out underside of the cockpit module, with air in
between. Now, I probably have enough of direct bonding, if I choose to
consider that the flanges are probably 100% bigger than they need to be, to
cater for the vagaries of homebuilding, but I can't put my wife and kids in
mine unless I have the "right amount" of residual "safety". So, how do I
fix it? Well, firstly I get the "bloody trouble light which scorned me as I
left it unemployed, hanging from the wall behind me as I bonded in the
module, and "use it". This is the biggest piece of advice. Please, don't
"not use" a trouble light. Voids, and the future anxiety and consequence
thereof are a real bugger. Well, to fix things you drill many holes, 1/2 of
which are a lesser diameter to exude air, and you spend the next few hours
going over every joint filling up all the voids. Then, you worry. Now worry
is what you don't want to do if you are a homebuilder. So, how do you not
worry when you have stuffed up? You put back "equivalent strength". Easy,
but heavy. Actually easy it is not, as a lot of the areas are awkward and
now inaccessible. I am going to use 2 or 3 ply BID straps on the front and
back of the seat portion of the module, the 2 spanwise ribs that have the
tank and flight controls within them. These straps will run from the bottom
of the boat up to the sill top, the middle of the fuse. I am going to
overlap the flanges of the module onto the adjacent skins, however remember
that the loads are now going outward laterally from the point that takes
the load. I should add that my module takes the load of my undercarriage up
through it, as I have a taildragger, but nevertheless this is irrelevant
to the conscience of a dedicated "perfectionist in undoing builder induced
problems". I could simply build a rib that runs around the top of the fuse
in an arch that transfers any upward force of the module into the space
immediately above the join in the fuse, which of course is continually
narrowing vertically.
There is a simple answer for you........................don't cheapskate on
the redux as the gain is not worth having. Be wary of the areas around
where the flight control bearings are, as you don't want to glue everything
up, and I can honestly say I didn't do that. Its a real sh*t to do
something that is unable to be undone, and have anxieties. So, be wary of
prioritising with "cocked up priorities". A light weight a/c is not all
that it is cracked up to be. If you disagree, well ..........tell me
directly, because those of us that go 3 forward and 2 back need to know this!
Reg
Tony Renshaw
Sydney Australia
Classic 236 B.B. Taildragger
Tail, Wings, Ailerons, Flaps Complete and Connected
Lower Fuse in Jig, and module most recently installed.
Tail Torque Tube installed.
Mass Balance assembly installed and deflections sorted
Roof Panel between doors completed.
Photos at:
http://forum.okhuijsen.org/TonyR
Intended Engine: 912S CS prop (model undecided)
Instrumentation: Garmin 296 Colour GPS beneath an electronic Artificial
Horizon, one that I can trust for short periods IMC, to get out of a sticky
situation
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