GREAT PLANES BLT, Instruction Manual

Page: 10 / 24

❏ ❏
7. Position the top 1/8" x 1/4" x 24" (3.2mm x 6.4mm x
609.6mm) balsa main spar in the rib notches with one end flush
with the outside edge of the root rib and glue to all the ribs.
❏ ❏
8. Cut one of the 1/8" x 24" (3.2mm x 609.6mm)
hardwood dowels so that it fits in the notches at the front of the
wing ribs, from the root to the tip rib. Glue the dowel to the ribs.
Save the excess dowel for use as a wing hold down dowel.
❏ ❏
9. To make a top trailing edge sheet , draw a line 1/16"
(1.6mm) from the edge of a second 1/32" x 3/4" x 24" (.8mm
x 19mm x 609.6mm) balsa sheet. Sand a taper along the
edge up to the line. The sheet should fit in the notches at the
trailing edge of the wing ribs and blend into the bottom
trailing edge sheet.
Hint: To avoid breaking the trailing edge sheet when
sanding the taper, sand across the grain, not lengthwise.
❏ ❏
10. Glue the top trailing edge sheet to the top of the
wing ribs and the aft edge of the bottom trailing edge sheet.
❏ ❏
11. From a 1/32" x 3/4" x 24" (.8mm x 19mm x
609.6mm) balsa sheet, cut and glue shear webs,
horizontally, to the top and bottom spars in the locations
shown on the plan. Make sure they are glued securely to the
wing spars and ribs.
Do not install shear webs in the rib
bay between the W1A ribs.
❏ ❏
12. From a 1/32" x 3" x 15" (.8mm x 76.2mm x 381mm)
balsa sheet, cut pieces to make the top center sheeting to
fit between the wing spar and trailing edge sheet and
between the wing spar and the leading edge dowel. When
satisfied with the fit, apply medium CA to the top of the W1A
ribs and press the sheet in place. Hold the sheet in position
until the CA cures.
❏ ❏
13. Carefully sand the top center sheeting flush with the
wing spar, leading edge dowel and trailing edge sheet.
10