Top Flite TOPA0905 - Manual (Page 32)

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5. This step will be easier if you have a second set
of hands to help you with the positioning of the cowl.
Slide the cowl onto the front of the fuselage. Press
the cowl back against the fuselage so that the sides
of the cowl are tight to the sides of the fuselage. Note
that the cowl has a pre-drilled hole in the top and both
sides of the cowl for the mounting screws. With the
cowl pressed in place and the engine centered in the
cowl, drill a 1/16" [1.6mm] pilot hole through the top
mounting hole in the cowl drilling into the fuselage.
(Note: When the cowl is properly placed, your pilot
hole will be through the fiberglass as well as a wood
plate that is pre-installed inside of the fuselage. Be
sure you have drilled through the wood plate).
Temporarily install a #2 x 3/8" [10mm] screw into the
hole in the top of the cowl and into the hole you
drilled. Re- center the cowl with the engine and repeat
this procedure for the other two mounting holes.
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6. Place the dummy engine over the engine. Then,
place the cowl over the dummy engine. Attach the
cowl to the fuselage with the temporary screws. To
position the dummy engine you will need two 7"
[180mm] balsa sticks and two small rubber bands
(not included). Loop a rubber band through a couple
of the aluminum tubes on one side of engine
crankshaft. Insert the stick through the rubber bands
and place the stick onto the front of the cowl. This will
pull the dummy engine into the front of the cowl.
Repeat this with the second stick and rubber band on
the other side of the engine crankshaft.
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7. Position the dummy engine so that the cut out is
over the engine cylinder and the hole you cut in the
center of the dummy engine is centered on the engine
drive washer. Be sure the center cylinder on the dummy
engine is centered at the top of the fuselage. When you
are satisfied with the positioning of the dummy engine,
carefully remove the cowl from the fuselage, being
careful not to disturb the dummy engine.
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8. Using medium CA, tack-glue the dummy engine
to the cowl from inside the cowl. Re-install the cowl
to the fuselage to verify that the dummy engine is
placed properly. When you are satisfied with the way
it fits, remove the cowl from the fuselage and
permanently glue the dummy engine to the cowl from
inside the cowl with 6-minute epoxy mixed with
microballoon filler.
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9. Drill through each of the three mounting holes
you drilled in the fuselage with a 5/64" [2mm] drill bit.
Install and remove a #4 x 1/2" [13mm] screw into each
hole. Apply a couple of drops of thin CA into the holes
to harden the threads. After the glue has hardened,
the cowl will be mounted to the fuselage with three
#4 x 1/2" [13mm] screws and three #4 flat washers.
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10. Make any necessary cut-outs for the muffler,
needle valve, etc. If you are using an engine that would
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