modelers may disagree and feel that a side mounted, or even an
upright engine installation would be preferable. For this reason,
the Rascal 110 fuselage comes with a clean firewall, without any
pre-drilled motor-mount holes. This allows you to choose the best
engine and muffler installation for your airplane.
Obviously, whatever engine you use, it must be able to fit within the
cowl and must have a mounting base, (motor mount), "footprint"
that will fit onto the firewall. To assist you in planning for your
choice of engine and its installation, the following photos and
dimensions may be helpful.
Photo #1 shows a cut-away cowl mounted to the fuselage. As you
can see, there is a maximum distance of about 6" from the front
face of the firewall to the front edge of the cowl. This means that
the combined distance from the back surface of the motor mounts
to the backplate surface of the spinner can be as far as 5-7/8", still
leaving a 1/8" gap between the front of the cowl and the back of
the spinner.
Photo #2 shows a side view of the fuselage with two vertical
reference lines drawn on its side, just behind the firewall location.
These two lines represent the furthest forward that the cowl can be
mounted (the forward line) and the furthest back it can be mounted
(the rear line). As you can see, the cowl can be positioned, front
to rear, by as much as 1/2".
Photo #3 shows the front face of the firewall with the vertical and
horizontal centerlines.
These two lines represent the correct
centered position of your engine when it is mounted to the firewall.
These lines are to be used for measurement reference.
4-STROKE ENGINES:
The following steps will show the installation of a Saito 1.50 four-
cycle engine. The engine will be mounted in the inverted position.
To make the initial fitting of the engine to the mounts more
convenient, remove the muffler and header pipe for now. We also
suggest that you remove the screws holding the windshield in
place to the fuselage and set these parts aside for now.
❑
1) From the kit contents, locate the Motor Mount Assembly
bag. In addition, you will need the engine mounting bolts (not
included) for your particular engine. In the case of the Saito 1.50,
we used 8-32 Allen Head bolts with 8-32 lock nuts for this purpose.
The first step is to properly mount the engine itself to the motor
mount arms.
A very easy and accurate way to do this is to
temporarily mount the two motor mount arms onto a scrap piece
of 1/4" plywood, with the correct spacing for your engine. Doing
this ensures that the back faces of both mounts are truly flat in
10
Photo #1
Photo #2
Photo #3
IMPORTANT NOTES:
1) The motor mounts provided with the Rascal 110 ARF kit
are of excellent quality and designed to work well with 2-stroke
engines up to 1.20 displacement and 4-stroke engines up to
1.50 displacement. DO NOT use any engine larger than these
with these motor mounts. Replace the mounts with engine
mounts designed specifically for larger engines.
2) DO NOT mount your engine on these motor mounts by
drilling and tapping them for bolts or screws! These mounts
should be drilled for clearance of the engine mounting bolts and
the engine secured to the mount arms with bolts, washers, and
lock nuts. Tapping threads into these motor mount arms may
weaken them, potentially causing them to fail.
6”
1/2”
