GREAT PLANES RV-4 Instruction Manual page 13

22. Sheet the top of the wing between the outboard W2 ribs
from leftover 3/32" x 4" x 30" [2.4 x 102 x 762mm] balsa sheet.
23. Locate the 5/8" x 1-3/4" x 7" [15.9 x 44 x 178mm]
balsa block. Cut it into two 3-1/2" [89mm] long pieces.
24. Fit one of the balsa blocks between rib W1 and W2
at the trailing edge of the rib.
25. On the block make a mark 1/8" [3mm] from the
end. Draw a line from that mark to the corner as shown in
the photograph.
26. Sand the end of the block to the line you just made.
27. From the end of the block where you sanded the
taper into the block, measure forward 3/4" [19mm] from the
leading edge and draw a line across the block.
28. Locate the die-cut 1/8" plywood WBS. On each end
measure in 1/8" [3mm] and draw a line across WBS.
29. From the line out to the edge, sand the plywood to
a thickness of 3/32" [2.4mm].
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