User Manual

18
Mount the Cowl
Now that you can get the cowl to fi t over the engine it is
time to determine how the cowl will be mounted. There are
two options: You can use the standard wood screws from
the outside, or use the optional cowl ring. Review the cowl
fi tting process to decide which way you prefer. The cowl ring
requires fabrication of an extended ball-end hex driver, but
the installation is “cleaner” and more durable as there will be
no external screws.
METHOD 1: Mounting the Cowl with the Cowl Ring
If using the cowl ring, fi rst make an extended hex driver…
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A. Use a Dremel with a fi ber-reinforced cutoff wheel to
cut a Great Planes 3/32" Hex driver ball wrench in half. Then
cut a 4" [100mm] section from a 4-40 (.095") pushrod wire.
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B. Grind 1/2" [13mm] of the joining ends of the hex
driver so the included brass tube couplers will fi t over the
ends. Then use coarse sandpaper to roughen both ends
of the pushrod wire.
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C. Use silver solder with plenty of acid fl ux (that comes
with silver solder) to join the pushrod wire between the
ends of the hexdriver with the brass tubes. The key to a
good soldering job is fi rst to tin the ends of the hex driver
and the pushrod wire—for the hex driver this requires
continually heating the ends and quenching them in fl ux.
After doing this several times the ends of the hex driver will
be thoroughly tinned and ready for joining.
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D. After all the soldering is done use a small paper
towel square dampened with acid fl ux to clean residual
fl ux from the wrench. Then follow with steel wool and a
thin coat of oil.
Now let’s get back to the cowl ring…
❏
1. Round both ends of the included 1/8" [3.2mm]
hardwood dowel and cut it in half. Glue the dowels into the
cowl ring with 1/4" [6.4mm] protruding from one side—this
will now be the back.
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2. Press two 4-40 blind nuts into the front of the top two
holes in the cowl ring.
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3. Use the remainder of the 4-40 pushrod you used for
extending the hex driver to pull two 4-40 blind nuts into the
back of the bottom two holes in F-1. Use a 4-40 screw with
washers to draw the blind nuts tightly all the way in. Carefully
add a few drops of thin CA around the blind nuts so they will
not pop out.