SIG RASCAL FORTY Assembly Manual page 8

be made with a 9/64" dia. drill bit.
6) Use the mounting hardware to now secure the engine in
place to the aluminum rails. We used and recommend 6-32 lock
nuts to secure the bolts.
interference, the threaded length of the mounting bolts must be
trimmed to no longer than 9/16". Re-install the engine - mounted
on the aluminum rails - back into the nose of the model and
temporarily secure the rails with the four M3 x 20mm bolts.
Basically, the engine is now correctly positioned and ready for final
mounting. What remains is to accurately locate and open the
required clearance holes for the engines' muffler, needle valve and
any other needed openings, such as a clearance hole for the fuel
filler valve, described earlier. To neatly create these openings, use
a Dremel ® Tool and various sanding and grinding bits, a drill with
various bits, some sandpaper, a hobby knife and a sharp pencil or
non-permanent marker pen.
7) Use a pencil to mark the approximate location of the muffler
manifold onto the inside surface of the engine compartment,
where it will exit. Likewise, mark the approximate location of the
engine's needle valve. Remove the engine and aluminum motor
mounts. With the engine out of the way, use a straight pin and a
Note that in order to fit without
pair of pliers transfer the marks to the outside of the fuselage. Grip
the pin tightly with the pliers, align the pin with the marks on the
inside of the engine compartment and push it through the fuselage
side and covering. This now shows you where to begin the holes.
Use a Dremel ® Tool and grinding bit to begin opening the muffler
exit hole, a little a time. Re-install the engine periodically to check
the proper alignment of your work.
The final muffler opening should leave about 1/16" clearance
around its outer surface. The edges of the opening should be
sanded smooth. To make the needle valve exit, begin with a small
drilled hole. With the engine in place, the hole should be opened
progressively, centering it exactly with the carb. The diameter of
the hole should be just a little larger than the diameter of the
needle valve body. Note that with some engines, it may be
necessary to make a music wire extension.
manufacturers have holes and set-screws in their needle valve
assemblies for this purpose.
With the engine in place in the nose, mount the muffler and needle
valve to check for final clearance and make any final adjustments
that might be needed.
8) If you are using the optional fueling valve, now is the time to
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Most engine