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45.
Cover both openings of the ballast tube with a little masking tape to prevent glue entering
the tube and then glue the ballast tube into its foam “jacket” using epoxy or PU glue.
46.
The ballast tube needs to be positioned
EXACTLY on the finished glider’s centre
of gravity (CG). This is to ensure that the
addition of ballast weight does not alter the
glider’s balance at all. Accurately measure
185mm (or your preferred CG location)
back from the nose and draw a line on the
BOTTOM surface of the wing at right
angles to the centre panel join line at this
point.
47.
Mark the halfway point on the ballast
tube’s foam jacket.
48.
Position the ballast tube (in its foam
jacket) on the bottom surface of the wing
so that its channel opening is directly on
top of the CG line you drew and also so
that it is centered over the centre wing
panel join line.
49.
Trace around the ballast tube’s foam jacket
with a pen and then cut along this outline
all the way through the wing and remove
the resulting foam plug.
50.
Test fit the ballast tube’s foam jacket into
this cut-out to ensure it fits snugly. Adjust
if necessary.
51.
Use PU glue (or epoxy) to glue the ballast
tube and foam jacket assembly into the wing so that the side of the foam jacket with the
ballast tube channel opening is completely flush with the bottom surface of the wing. Place
the wing in its beds while the glue is curing to ensure correct wing alignment.
52.
Once the glue has cured, cut off the excess foam from the foam jacket so that it is also flush
with the top surface of the wing. Sand smooth to form a clean continuation of the airfoil
shape.
53.
Mark out an area for a hatch to access the
ballast tube that is approximately 30mm x
45mm (1 1/8” x 1 3/4”) and directly next
to one end of the ballast tube on the bottom
surface of the wing.
54.
Cut along this outline all the way through
the wing and then remove the resulting
foam plug. Mark a line vertically up the
foam plug’s front side for later reference.
55.
Mark
out
the
required
depth
(approximately 18mm or 11/16”) of the
access cavity on the foam plug on all sides
and then cut the foam plug in two along
this line.
