Great Planes Piper J-3 Cub 60 Kit - GPMA0162 - Manual (Page 30)

D 9. Slide the previously assembled aft fuselage top into
position so the formers key into the slots. Glue the aft
fuselage top to the formers and fuselage sides.
D 10. Glue the cabin doubler to the aft fuselage top.The
cabin doublers may have to be slightly bent inward to
conform to the shape of the fuselage. D 14. Remove all three pieces and trial fit the LTF and
TTF in the back of the firewall. It is important that the front
edge of the LTF and TTF fully contact the back of
the firewall.
D 11. Do not use any glue until instructed to do so.
Trial fit the die-cut 1/8" plywood lower tank floor (LTF) in
the fuselage making sure the embossed designation "LTF"
is facing upward - this sets the thrust angle of the firewall.
D 12. While the LTF is in position, trial fit the die-cut 1/8"
plywood top tank floor (TTF) facing upward. The notch in
the left upper fuselage doubler will have to be enlarged to
accept the TTF because the fuselage doublers are
identical although right thrust must be built in.
D 15. Reinstall LTF, TTF, cabin brace and the firewall into
the fuselage. Practice clamping the fuselage sides together
around the firewall and tank floors, making sure the firewall
fits into its notches. Use hardwood sticks, or similar, to evenly
distribute the force of the clamps on the fuselage sides.
Clamp the sticks together with masking tape, lots of rubber
bands or clamps. Once satisfied with the fit of all parts,
securely glue them together with 30-minute epoxy.
D 16. While you still have an open, accessible structure,
inspect all glue joints to make sure the tank floors, cabin
brace, and all formers are securely bonded. Apply fillets of
thick CA where required. Sand the tab at the top of the
cabin doubler flush with the back of F2.
D 13. Trial fit the die-cut 1/8" plywood cabin brace with
the TTF. You may have to remove the TTF, insert the
cabin brace in the TTF, then reinstall the two
pieces simultaneously.
D 17. Before we continue, now is a good time to fuel proof
the fuel tank compartment. We recommend brushing on
one of the following: 30-minute epoxy thinned with a little
alcohol, polyester resin or K&B paint or dope.
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