Avoid Cockpit Module Anxiety
<tonyrenshaw@optusnet.com.au>
|
| 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!
| Tony Renshaw
| Sydney Australia
Tony,
You are a lot wiser I presume. I was. For the second challenge
in the gluing and pasting enterprise - putting the top on -
[a] Ensure you have spacers inside the top which flex it outboard so that
when presented to the canoe, will hold it well out for prior inspection to
ensure proper 420 application (once you spang 'em together the adhesive goes
all over the place) AND strings to pull 'em out of the way when mated;
[b] Masking tape along every intended glue line about 3mm outside the
edge, so that you can 'scoop' excess shortly after initial application, and
then strip the tape when 1 hour old to prevent excessive slop. This requires
careful planning for the nether regions in the back;
[c] Do not use unfloxed fresh adhesive for plugging cleco/screwholes or
expect large globules to dribble down the inside. The waste hurts..........
Cheers for better gluing,
Ferg
|