Top Flite TOPA0500 - Manual (Page 15)

❏ 3. The same way you did for the stab, use your 1/4" x
5/16" rib jigs to hold the balsa fin ribs V1 through V7
over their location on the plan. Use a square to align the
ends of the ribs with the TE on the plan.
❏ 4. Cut the fin TE from a 1/8" x 1/2" x 24" balsa stick.
Align the top of the fin TE with the tops of the ribs allowing
the excess to protrude below the ribs (to be trimmed later)
and glue the fin TE to the fin ribs with thin CA.
❏ 5. Bevel the front of the fin ribs to accommodate the
fin LE. Cut the fin LE as shown on the plan from a 5/16"
x 15" shaped balsa stab/fin leading edge stick. Glue the
fin LE to the fin the same way you did the stab with the
excess protruding below the ribs.
❏ 6. Rearrange any T-pins that protrude above the
structure so they will not interfere with your bar sander.
Lightly sand the top of the LE and TE to match the airfoil
shape of the ribs to accommodate the fin skin.
❏ 7. If you haven’t yet done so, cut out your fin skins.
Sheet the left side of the fin with one of your fin skins
(don’t forget to use your left skin so the best looking side
is out). Make sure you position the skin accurately
because the bottom of the skin is what determines the fit
of the fin to the stab.
❏ 8. Remove the fin from your building board and trim
off the jig tabs. Trim the LE and TE to match the ribs.
❏ 9. Cut the fin hinge blocks from your leftover rib jigs
and glue them to the TE of the fin where shown on
the plan.
❏ 10. Sheet the other side of the fin with your other fin
skin. Be careful not to build any twist into the fin as you
press the skin in place.
❏ 11. Use your bar sander to sand the TE and top of the
fin square and even.
❏ 12. Trim 1/16" from the top of the die-cut 3/32" balsa
rudder core. Mark the location of the rudder ribs on
both sides of the rudder core.
❏ 13. Cut the remainder of the 1/4" x 3/4" x 30" balsa
stick you used for the elevator LE’s to the length shown
on the plan for the rudder LE. The same way you did for
the elevator LE’s, use a straightedge to draw a line 5/16"
from one edge of the rudder LE. Glue the die-cut 3/32"
balsa rudder core to the LE along the line. Use a square
to make sure you glue the core perpendicular to the LE.
❏ 14. Tack glue the rudder LE, centered, to the fin TE
with about four small drops of medium CA. Note that the
top of the rudder core is aligned with the top of the fin.
❏ 15. Use a razor plane or your bar sander to shape the
leading edge of the rudder to match the fin.
❏ 16. Refer to the following photo. From the 5/8" x
1-1/4" x 13" balsa block cut a 3-3/4" long piece for the
fin tip, 2-3/4" long piece for the rudder tip and a 3-1/2"
long piece for the rudder base. Glue the tips and base
in position (do not glue the fin tip to the rudder LE).
❏ 17. Use two 1/16" x 5/16" x 24" balsa sticks to make
the rudder ribs and glue them to the rudder core.
❏ 18. See the following photos and carefully taper the
rudder ribs and the rudder tip and rudder base toward the
rudder TE. Make sure you sand the ends of the ribs to a
point the same way you did for the elevator ribs. Carefully
shape the fin tip and the rudder tip to match the plan and
each other. Finish by rounding the leading edge of the fin,
then the fin and rudder tips. Don’t worry about shaping
the bottom of the rudder at this point. We can do that
when we join the tail cone to the fuse and rudder.
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