Great Planes Giant Extra 330L Kit - GPMA0250 - Manual (Page 40)

❏ 9. From leftover 1/4" x 1/4" balsa, cut two 2" long fin
locators. Glue the two locators as shown in the photo,
being careful not to glue the fin in place. Remove the fin
and set it aside. NOTE: These fin locators will be used to
properly position your fin later.
❏ 10. Select the five 3/32" x 4" x 36" long sheets, and
carefully inspect all 5 sheets. Select the softest sheet for the
center piece. Edge glue the 5 sheets, creating the turtle
deck sheeting. NOTE: The center sheet has to do a sharp
bend. It is important that you use the softest sheet to
minimize the chance of it splitting.
❏ 11. Wet one side of the sheet liberally. This will be the
outside of the turtle deck sheeting. Let the sheet set flat for
5 minutes to allow the water to soak into the sheeting.
❏ 12. Position the sheet over the turtle deck with the center
sheet centered on the top stringer and a small amount of
excess hanging behind the trailing edge of the fin plate (do not
end the sheeting at TD4). Lay very wet paper towels along the
center sheet and allow gravity to start to curve the sheet for
approximately an hour. Respray the entire sheet and the paper
towels and gradually pull the sheeting down. Repeat this
process until the sheeting hangs easily over the deck.
❏ 13.When the sheeting has curved enough, clamp the sides
to the fuse bottom on both sides and clamp the rear of the
sheeting across the rear of the fuse. Allow the sheeting to dry
completely overnight. NOTE: This is probably the most time
consuming step of the entire kit. Take your time and be
patient, being careful not to split the sheeting. If you are
patient and allow the water and gravity to work together, the
sheeting will bend smoothly and cleanly and you’ll get a great
looking turtle deck. If you try to rush it you will likely split the
sheet and have to start over again.
❏ 14. Double check that the sheeting is completely dry
before continuing. While the sheeting is still clamped in
place, lay the fuselage on its side. Using a straight edge,
trim the left side of the sheeting flush with the top of the
outer box longeron. Trim the right side of the sheeting 1/4"
below the outer box longeron.
❏ 15. Using medium CA, glue the turtle deck sheet to the
left side gluing stringer and longeron.
❏ 16. Confirm that the sheet is tight against the formers,
and trim the right side a little at a time until it mates to the
gluing stringer and longeron.
❏ 17. Roll the sheeting back, on and off the stringers a few
times until you can position it easily. Make sure it has good
contact with the stringers and formers along the whole
length of the turtle deck. When you are confident fitting it,
lay a bead of medium CA along all the turtle deck stringers,
formers, and the right side gluing stringer and longeron.
Position the sheeting in place and hold firmly along the
stringers and formers until the CA has fully cured. NOTE: It
is not as important that you get glue on every joint as it is
that the sheeting makes good contact with all the stringers
and formers along the whole length of the deck. This
sheeting is a critical structural component of your
aircraft and must be well fitted. In the next step you can
catch any places where you did not get a good coating of
CA, but only if you made good contact in this step.
❏ 18. Once the CA has dried, turn the fuselage upside
down and use thin CA to back up any places where the
sheet did not get adequately glued, but only if the sheet is
already making good contact. If it is not and you attempt to
force it now, you will likely split your sheeting and have to cut
it off and start over.
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