GREAT PLANES RV-4 Instruction Manual page 11

Position the rib over the third set of notches and then twist
it into the notch. Do not glue them to each other at this time.
6. Using your plan as your guide, install the remaining
W3 ribs into the proper notches. Do not glue them in place
at this time.
7. Install two W2 ribs at the location shown on the plan.
Do not glue them at this time.
8. Locate two 1/8" x 1/4" x 30" [3 x 6 x 762mm]
basswood wing spars. Cut them to a length of 26-1/4"
[667mm]. Place one of the spars at the location shown on
the plan. With all of the ribs now positioned on the wing
shear web (WSW), place WSW and the ribs onto the
basswood wing spar. Then place the top wing spar into the
notches. Do not glue the assembly together at this time.
9. Locate the die-cut 1/8" [3mm] balsa wing trailing
edge (WTE). Insert it into the notches at the trailing edge of
each of the ribs. Be sure that the tab end of WTE is at the
wingtip. Do not glue them in place at this time.
10. Position the remaining W2 rib at the wingtip and the
W1 rib at the wing root. Note: Refer to the wing root detail
cross-section for proper orientation of the W1 rib. When you
are satisfied with the fit of all of the wing components, glue
them together with thin CA.
11. Locate the 5/8" x 1/4" x 24" [15.9 x 6 x 457mm]
balsa stick. Cut a piece to fit between the two W2 ribs. This
will be the forward balsa wing tip. Glue it in place.
12. Locate the 1/16" x 1/2" x 30" [1.6 x 13 x 762mm] balsa
sub leading edge. Use a butt joint at rib W1 and then glue it
in place on the front of each of the ribs. After gluing it in place,
lightly sand the top and bottom of the sub leading edge with a
sanding bar making sure it matches the shape of the ribs.
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