Top Flite TOPA0140 - Manual (Page 44)

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13. Glue the die-cut 1/8" [3.2mm] plywood cowl
former and the four 3/8" x 5/8" x 5/8" [9.5 x 15.9 x
15.9mm] hardwood cowl blocks in place.
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14. Mount your exhaust system. We used the
Top Flite In-Cowl Warbird Muffler and appropriate
Top Flite In-Cowl header. Since the muffler is far
from the engine, you must use a long Silicone tube
to connect them. We used an Aerotrend 3/4"
[19mm] (inside diameter) Silicone tube
(AERG2220) with the included
spring-sleeve inside
the tube to prevent the hot exhaust gas from
burning through the silicone. Before you mark the
location of the muffler mounting screw holes,
temporarily insert a 3/32" [2.4mm] balsa
spacer
between the muffler and the tank floor so the top of
the muffler does not contact the fuel tank floor.
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15. Cut the molded right and left ABS cowl halves
along the cutlines. Hobbico (HCAR0667) or Kyosho
(KYOR1010) curved plastic cutting scissors work well
for this. True any jagged edges with a bar sander and
80-grit sandpaper.
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16. Thoroughly sand the inside and the
outside of the joining edges of both cowl halves
with 150 to 240-grit sandpaper. Basically, you
should sand everywhere you want glue and filler to
adhere, including a 1" [25mm] wide strip along the
joining edges of both cowl halves.
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17. Join the cowl halves and hold them together
with masking tape. Glue the cowl halves together
with thin CA. Avoid using accelerator because it
may soften the plastic.
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18. Place the cowl on the fuse and put your
spinner backplate on your engine. Align the front of
the cowl with the spinner backplate. Use a pencil
to mark any
high spots that need to be trimmed at
the rear of the cowl. Remove the cowl, trim, then
test fit again. Continue to test fit and trim as
necessary until the cowl fits the fuselage and you
have a 3/32" [3mm] gap between the front of the
cowl and the spinner.
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19. Once you are satisfied with the fit of the
cowl, mark the location of the cowl mount blocks
on the fuse.
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20. Position the cowl and hold it to the fuselage
with tape. Drill 3/32" [2.40mm] holes through the
cowl and the cowl mount blocks 3/8" [9.5mm]
forward of the aft edge of the cowl. Don’t worry if the
top and bottom holes you drill are on the seam
because you will reinforce the cowl with glass cloth.
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