QuiQue's Aircraft Yak-54S Assembly Manual - page 25
Step 4
Determine the location of the holes
on the firewall for installing the
engine mount, mark them and drill
the holes through the firewall using a
#3 drill bit .213 of an inch in diameter
to accept the blind nuts provided. A
good tool for the centering of the
holes for mounting the engine is
available from Central Hobbies. See
Figure 35. It has a small drill bit
which you turn by hand to locate a
starter hole and mark before drilling
the final holes for mounting the
engine.
Figure 35
The lengths of the blind nuts for
mounting the engine are a little too
long for the firewall. They will
protrude through the front of the
firewall. So you will need to counter
sink a clearance hole in the back of
the plastic engine mounts. Use a no.
1 drill bit, .228 inches in diameter
and drill a clearance hole that is
about 1/8 inch deep into the back of
the plastic engine mounts which will
accept the blind nut protrusion
through the front of the firewall. Use
a slow speed on your electric drill
and also do not push too hard. Do
this procedure very slowly, as would
a brain surgeon. Don’t need any slip-
ups here. Your engine after
mounting should look something like
this. Figure 36 and 37.
Figure 36
Figure 37
Step 5
After the engine is mounted, install
the throttle control that is provided to
the throttle servo. Depending on your
choice of an engine, the throttle
control rod may enter either the left
side or right side of the fuselage
passing by the fuel tank. In either
case it is not a problem as the
engine control servo is mounted to
accommodate the control rod
connection on either side. The
engine box will be finished later. The
top needs to stay open at this point
so you can install the fuel lines more
easily. The fuel lines from the engine
to the fuel tank should enter through
the round hole in the firewall.
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