Top Flite TOPA0704 - Manual (Page 30)

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3. Cut the front of the fuselage on the lines you have
drawn removing only the balsa wood. Cut the balsa,
making clearance for the blocks so that they can slide
into the fuselage. The blocks should slide back against
the plywood ring the balsa is glued to. When the blocks
are properly positioned, the distance from the front of the
block to the front of the fi rewall box will be approximately
7/16" [11.1mm]. Take a minute to mark each block so
that you know which are the right, left and bottom sides.
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4. This step will be easiest if you have someone
help you. With the two blocks in position (do not glue
them yet), place the cowl ring in place on the front of
the fuselage. The ring needs to be centered on the
fuselage. While holding the cowl ring in place have a
helper drill a 1/16" [1.6mm] pilot hole into the face of
the block, making sure it is centered in the hole in the
cowl ring. The hole does not have to be drilled very far
into the block, just deep enough to provide a starter
hole for the fi nal drilling you will do in the next step. Do
this for both blocks.
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5. Remove the blocks and drill a hole through each of
the blocks with a 5/32" [4mm] drill bit. It is important that
the hole be drilled straight. This will be best accomplished
if you can put the block in a drill press vise and drill the
hole with a drill press. If you do not have access to a
drill press, be sure you are careful to drill the hole as
straight as possible.
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6. Install a 6-32

1-1/2" [38mm] socket head cap
screw and #6 fl at washer into the front of the hardwood
block and thread a 6-32 blind nut onto the screw. Tighten
the screw, pulling the blind nut into the back of the block.
Do this for both blocks.
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7. Place the blocks back into position on the fi rewall
block. Locate two 5/8"

3/4"

1" [16 mm

19 mm

25mm] hardwood blocks. Place each of the blocks
against the fi rewall box as shown in the photo. The
block will rest against the side of the fi rewall box and
the balsa fuselage. The block will rest in place without
any glue for this step.