Fabricating
a gap seal or fairing that fills the gap and contours the wing intersection
to the fuselage cage and windscreen has been one of the most difficult steps
in the construction of the Mark III, for me. That may be because at this
stage in the game I have little interest in putting so much effort into a
part that was actually provided in the kit. For whatever reason, the stock
gap seal did not fit our aircraft. I know the MK3 kit is constantly evolving
and different builders end up with different results; but this part did not
even come close to fitting. On top of that the fiberglass in the fillet
areas has voids where the layers where not compressed or wetted out
properly. The truth is that Scott and I probably have too high of
expectations so we decided to take a shot at making our own. After pursuing
this project I have a little more appreciation for Kolb’s effort. What a
project!
We began by
installing a sacrificial windscreen, Cintra, aluminum, tape, foam, and
whatever else we could conjure to fill the gap. Release wax was then
liberally applied to all of these materials in hope that we might reverse
the mess we where about to make of the plane. A couple of layers of
fiberglass and multiple applications of a micro balloons/ resin mix began to
reveal a shape we could live with. Oh yeah, and enough sanding to build my
forearms to super Popeye strength or cause permanent crippling arthritis,
I’m not sure which.
(if it's arthritis Paul won't be
able to fly the finished plane so I'm sure he'll be fine.)
Step 42 – apply at least 5 coats of release wax. Finally, we put down 4
layers of fiberglass cloth to make the actual part. Did I say finally? Scott
thought it might be a good idea to make a mold of this part just incase we
might ever need to replace it in the future. This is why you see the green
coloration. At this point we have applied several coats of PVA mold release
and wax in order to make a negative mold for the gap seal. You can also see
a faint pencil line depicting the shape of the final finished piece. A gel
coat and several more layers of fiberglass, foam and wood will be added to
create the mold but at least there should not be any more sanding
required.
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Beginning the basic shape.
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Use whatever it takes to form the shape you want.
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One layer of fiberglass over the whole mess of parts. A bunch of filler over the glass and sanded to shape
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Filler was waxed then 4 layers of glass were added for the actual part
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The part was sprayed with PVA, then waxed. Gelcoat for the mold is being rolled on over all previous layers
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Let the gelcoat cure a little. This will be the inside surface of the mold.
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3 layers of cloth get laid into the gelcoat.
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Compound curves are such fun!
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Thickness to a layup helps make it strong.
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Blue foam is perfect for this. Strong, cheap, and lightweight.
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It took about 1.5 hours to lay all the foam blocks in the wet resin. One layer of glass on the outside holds it all together.
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And here's the mold ready for wet sanding.
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The mold was made so we could make ourselves another center section if ours gets damaged.
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Cutting the actual part to rough shape with a $7 Harbor Freight air tool.
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We may offer a few center sections for sale in the future.
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If we do offer them for sale they will not be cheap.
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But you can expect to get a high quality part made with high quality materials.
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