Top Flite TOPA0500 - Manual (Page 52)

❏ ❏ 14. Gather four die-cut 1/16" plywood cowl ring
doublers. Cut 1/16" half notches , 1/8" deep, on both
ends of all four ply cowl rings as shown in the sketch.
❏ ❏ 15. Build a cowl ring from two die-cut 1/8" balsa
ring doublers and two die-cut 1/16" plywood cowl ring
doublers. Cut notches in the balsa cowl ring using the
notches in the ply cowl ring as a guide. Build a second
cowl ring the same way. Drill holes in both cowl rings for
your fuel lines. You can see the cowl rings and the holes
in the following photos.
❏ ❏ 16. Glue one of the cowl rings, with the ply side
facing the front, centered, to the front of the nacelle with
the notches keyed in the stringers. If necessary, notch
the inside of the cowl ring for the throttle guide tube.
Temporarily mount your engine and engine mount.
❏ ❏ 17. Determine where to position the three 1/2" x
1/2" x 1-1/16" basswood cowl mounting posts (refer to
the photo at step 5 on page 54). You must locate them
where they will not interfere with the needle valve,
muffler, fuel lines or engine. Try to space them as evenly
as possible.
❏ ❏ 18. Mark the locations you have determined for the
cowl mounting posts on the aft cowl ring on the nacelle.
Cut three 1/2" long cowl ring spacers from the 3/8" x
1/2" x 9" long basswood stick and glue them to the
nacelle where you have marked the cowl ring for the
mounting posts (the cowl ring spacers support the cowl
mounting posts).
❏ ❏ 19. Remove your engine. Temporarily place the
front cowl ring on the stringers (balsa side facing
forward) resting on the cowl ring spacers. Mark the
location of the cowl mounting posts over the cowl ring
spacers. Remove the cowl ring. Notch the balsa down to
the plywood for the cowl mounting posts.
❏ ❏ 20. Reposition the front cowl ring and glue it in
place. Add 1/8" x 1/8" side stringers.
❏ ❏ 21. Sand the stringers and formers so they blend.
❏ ❏ R22. Use the nacelle bottom sheeting pattern on
the fuse plan to make a skin for one half of the bottom
of the nacelle from a 1/16" x 4" x 24" balsa sheet.
Remember to make your skin slightly larger than
indicated to allow for trimming and positioning. Wet the
outside of the skin with water and bend it into position as
you test fit and trim it for a good fit. Once you get the
correct shape, use the first skin as pattern to make the
second skin before you glue it in place.
❏ ❏ R23. Glue the skin to the nacelle formers. It’s
easiest to glue sheeting to the wing first, then bend and
glue it to the formers. Trim the skin as necessary so the
wheel will fit when you retract the gear.
❏ ❏ R24. Glue the skin to the bottom of the other side of
the nacelle the same way.
❏ ❏ F25. Use the nacelle bottom sheeting pattern on
the plan to make a skin for one half of the bottom of the
nacelle from a 1/16" x 4" x 24" balsa sheet. Remember
to make your skin slightly larger than indicated to allow
for trimming and positioning. Wet the outside of the skin
with water and bend it into position as you test fit and
trim it for a good fit. Once you get the correct shape, use
the first skin as pattern to make the second skin before
you glue it in place.
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