Great Planes PT-60 Kit - GPMA0119 - Manual (Page 21)

D 4. Glue the two die-cut 1/8" balsa rear center ribs R-1C
to each other with thin CA.
D 5. Locate the two die-cut 1/8" ply front center ribs R-
1A and the die-cut 1/8" balsa front center rib R-1B. Glue
these together using 6-minute epoxy, with the balsa rib
sandwiched between the two ply ribs.
D 6. Locate the four die-cut 1/8" ply dihedral braces. Use
6-minute epoxy to glue only two of the parts together—
then make a second pair.
TWO WARPED SPARS INSTALLED
THIS WAY WILL RESULT IN A
STRAIGHT WING
TWO WARPED SPARS INSTALLED
THIS WAY WILL RESULT IN A
WARPED WING
D D 2. Examine the four grooved 3/8" x 5/8" x 36" main
spars for warps. Refer to the sketch above, then divide
them into pairs. Cut only one of the spars to 33-7/8".
Without gluing, pin the spar on top of the balsa sheet
flush with the rear and outer edges. Use the pinning
method shown above at enough locations to hold the spar
straight over the plans.
Both wing panels are built directly over the plans. Don't
forget to cover the plans with waxed paper before starting.
Build the right wing panel first so that your progress will
look the same as our photos. Note: For photographic clarity
we took the photos of the framework removed from our
building board, even though we too build over the plans.
D D 3. Insert the die-cut 1/8" balsa slotted web into the
spar groove. The pointed end is at the outboard R-5 with
the slots pointing upward. Insert an R-5 into the end slot,
then slide it (and the slotted web) until the rib is flush with
the spar end. Remember, don't reach for the glue bottle
until "Simon says."
D D 1. Cut one 3/32" x 4" x 36" balsa sheet lengthwise
along both edges to make it exactly 3-9/16" wide. It's best
to cut both edges to be sure the sides are parallel. Square
off what will be the outboard end with a sanding block, then
trim the root end (inboard) so the sheet will be exactly
33-7/8" long. Pin it over the plans, flush with the rear edge
of the main spar and the outer edge of R-5.
D D 4. Cut two 3/16" x 3/16" x 36" balsa forward spars
to 33-7/8". Insert one of the forward spars into the square
notch on the bottom of R-5. Align the end of this spar with
the end of the balsa sheet. (See the next photo
for reference.)
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