Great Planes PT-60 Kit - GPMA0119 - Manual (Page 22)

D D 5. Install all remaining ribs from R-2 through R-5. Be
sure that the R-2/R-3 laminated rib assembly has the R-2
rib facing the center of the wing. Check that all ribs are
fully seated and touching the bottom sheeting.
D D 9. Center the R-2 and R-5 ribs vertically between the
top and bottom of the TE. A scrap of 3/32" balsa can be
used as a shim under the rear portion of these ribs to raise
them to the correct height. Press the LE down to the
building board.
D D 10. Look the frame over carefully to be sure
everything is fully pressed into position and aligned with
the plans. We are about to start gluing so now is the time to
fix any problems.
D D 6. Cut a grooved 3/8" x 5/8" x 36" top main spar to
35-1/8". Carefully press the top grooved main spar and
3/16" forward top spar into position. The outer end of only
the top main spar should extend past the outboard R-5
rib by 1-1/4".
IMPORTANT:
Follow the gluing sequence exactly and don't glue the
sheeting to the bottom of the ribs until after the wing is
joined and installed in the washout jig — just tack glue it
to the bottom spar and LE in three or four places. Tack
gluing means that you only use a tiny drop of CA to hold
the part in position.
D D 11. Okay, "Simon says, GLUE!" Use thin CA for all
points of contact (except the bottom sheeting) starting
with the notches along the TE. Press or hold all of the parts
in position as you apply the CA. Move on to the main spar
and slotted web, the rib/spar joints and the LE.
D D 7. Separate the shaped 36" balsa leading (LE) and
trailing edges (TE) with a sharp hobby knife as shown in
the sketch.
D D 8. Notice that the notches on the LE and TE are
closer to one end than the other. The shortest distance is
positioned toward the R-5 ribs. Carefully fit the LE and TE
onto the ribs.
D D 12. Remove the pins holding the wing panel to your
building board. Hold it with the LE pointing down, then wick
thin CA into the top main spar / slotted web joint from both
sides of the web. Notice that we use a tubular CA applicator
tip (Hobbico HCAR3780) on our CA bottle. Applicator tips
help control thin CA placement and are a cheap and handy
item to have around the shop.
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