Tony,
Yes it is possible, but take your time and make yet another flange to be
able to glue the all too important back bulkhead to the top. The short
answer is the baggage bay bulkhead sticks up only a little higher than
the rear bulkhead so it is worth it in my opinion to leave it alone and
glass it in later...
Now the reasons (read as the long and boring answer):
I am getting less maneuverable with age so anything I can do to finish
the lower canoe and make my time in the aft fuselage more comfortable, I
try to do. It is no secret that I glass in my baggage bay floor prior
to putting the top on. Much fitting and adjusting is necessary adding a
number of hours of trimming, measuring, and fitting. However all the
tasks of installing trigears, and fitting rear mounted batteries, flap
drives, antenna planning, fuel pump installation, wiring, guiding rudder
cables, fuel and brake lines, and the tedious upside down work glassing
of those baggage bay supports, becomes a snap. If time is taken to
properly prep the bulkhead and make a flange on the inside of the top,
it makes the task of crawling in the rear of the aircraft a final
inspection and hookup exercise rather than a construction exercise.
This is important, and very welcome, when working alone where time is
not a factor.
A minor but important technical point is that the rear bulkhead has a
foam core, and I see many folks just cut the bulkhead to shape without
considering the edge of the bulkhead closeout. Technically the foam
core, if cut and exposed, needs to have the skins attached together by
cutting out the foam core material back 1/4 to half inch and filling
with flox (done when the part is attached to a flange forming an L
bond), or leave the foam exposed and glass the front and back (inner and
outer) skins to each side of the top forming a TEE FLANGE. Hard to use
words to explain, but the strength of composites in bending and buckling
is the foam core to fiberglass bond. We know the foam is supposed to be
hollowed out at the exposed edge and filled or tapered to make a glass
to glass bond, but that is forgotten many times with the bulkhead and
access panels. Note that in a perfect world, if we make a flange joint
in the aircraft, it is assumed to be a glass to glass bond. My
technique is, if I expose the foam core on the bulkhead, I glass both
sides so I don't have to cut back the foam and refill the void, or taper
the end, to get the important glass to glass bond. Refer to Chapter 23
or 33T on the techniques for a glass to glass bond.
I spend a lot of time making bulkhead flanges and mass balance tower
flanges fit perfectly so I can put the top on in one shot, and I rely on
my clecos and screws to hold the tabs and flanges in position, all while
keeping the top, tail and stab perfectly aligned until the glue dries.
The long pole in the tent is that the top has to be final fitted (many
times) and clecoed on as if it were just glued in so all your flanges
have the right shape and position...
On a personal note, if you leave your bulkhead alone, sticking up, and
spend the time in the hole later, glassing the flange in position, it is
actually faster and stronger to just leave your bulkhead loose and crawl
in and glass it in place on both sides after the top is on. All it
takes to keep the bulkhead where you want it for glassing, is to tack in
a small block of foam or wood to keep the bulkhead fixed and steady.
In my opinion, if you you can't get into the hole, get a smallish
helper, and train him, it is faster and cheaper. The baggage bay
bulkhead sticks up only a little higher than the rear bulkhead and
allows any wire tabs or attachments to be fitted and clearanced also, so
it is worth it in my opinion to leave it alone and glass it in later...
Regards,
Bud
----- Original Message -----
From: Tony Renshaw<mailto:tonyrenshaw268@gmail.com>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Friday, September 16, 2011 3:03 AM
Subject: Europa-List: Baggage Bay Upper Fuselage Attachment
<tonyrenshaw268@gmail.com<mailto:tonyrenshaw268@gmail.com>>
I'm trying to minimise the amount of redux and work needed to get a
good job gluing on this top. It aint for some time yet, but I'd like to
bond in my extended baggage bay floor, and bulkhead. I can do this but
then it sticks up in the breeze acting as a nuisance. I've already layed
up flanges on the arched section to mate with the roof, but what I'd
really like to do is cut it off, and bond it on later, once the top is
on. It will be easy as I'll just redux it in as one piece, and then I
only need to do strapping patches both front and back of the cut areas.
Does anyone see anything wrong with doing this?
Reg
Tony Renshaw
Sydney Aussie
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avigator?Europa-List>
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