Cowl Installation Tips
You may have your own method to adapt and install the cowl to fit your model, your choice of engine and your
choice of engine orientation... here is one method to add to your bag of tricks!
1) Use a sheet of card stock or better yet a sheet of clear thin plastic like that used to protect documents. Using
a clear sheet is strongly recommended.
2) Wrap the sheet as close as possible around the cowl, preferably tapered slightly towards the front. Tape the
sheet so that it stays in a cylindrical shape approximating the cowl. Trim the aft edge of the sheet to approxi-
mately match the aft edge of the cowl. Trim the front edge of the sheet to approximately match the front edge
of the cowl. Put a couple of registration marks on the dummy cowl and real cowl so that you can apply the
dummy cowl over the real cowl in a similar manner again. Now remove the sheet from the cowl, in one piece if
possible. If it is not possible to remove the sheet in one piece, use a felt tip pen to mark the sheet so that you
can untape it, then remove it from the cowl and then retape it back together into the cylindrical approximation
of the cowl. In effect you now have a rough dummy cowl that can be used to make a template to help you later
fit the real cowl.
3) Now install the engine on the engine mounts and measure the distance from the back of the engine mount
to the front of the thrust washer
4) Draw a vertical line on the forward face of the firewall so that it is in the middle of the firewall and at right
angles to the horizontal line drawn on the firewall at the factory. If there is no horizontal line on the firewall, check
the set up specs for this model and draw the horizontal thrustline at the location indicated.
5) Install the real cowl on the model and slide the cowl back until the distance from the firewall to the cowl nose
ring hole is similar to the distance measured in step 4 AND that at least 1/4 in (6mm) of the edge of the cowl
overlaps the front of the fuselage. Carefully square the cowl with respect to the fuselage so that it looks aligned
from the top, sides, bottom and front. Look through the cowl nose ring hole and try to align the centre of the cowl
nose ring hole with the intersection of the vertical and horizontal thrust lines onthe front face of the power mod-
ule. Measure the distance from the forward face of the firewall to the nose ring hole in the cowl. Use low tack
masking tape to hold the cowl loosely in place while you adjust it. Once you have the cowl squared up and set
where you want if fore and aft, apply a line of low tack masking tape around the circumference of the fuselage
so that the forward edge of the masking tape just butts up against the aft edge of the cowl.
6) Remove the real cowl from the model.
7) Install your engine mount and engine and muffer onto the model. Orient the engine to the position you
want...i.e upright, rotated 45 degrees inverted etc. Make sure the muffer and the carburetor are installed. When
selecting which orientation you want for the engine you need to keep in mind operational considerations... the
muffer for examine must clear the sides of the fuselage by at least 5mm and carburetor throttle arm must be
connectable to the thottle control rod running forward through the firewall from the throttle servo. Lastly, the fuel
lines coming through the stopper hole in the run to the muffer pressure tap and the carburetor fuel nipple.
8) Once you have positioned your engine mount and engine, secure them to the forward firewall of the power
module and install the forward firewall onto the model using the four mounting studs, nuts and washers. We rec-
ommend setting the forward firewall at zero degrees offset thrust for now. Use the same number of washers and
nuts on all four studs. You can adjust a bit of right or down thrust into the firewall later if required.
9) Remove the muffer and the carburetor from the engine. Set the muffer and the carburetor aside. Be careful
not to lose any parts.
10) Now try to fit the dummy cowl on to the fuselage. You will find that the dummy cowl will likely be obstructed
by the engine as you try to install it. Assuming you are using the recommended clear sheet material you will be
able to see where the obstruction begins. Using a left tip marker mark the area onthe dummy cowl to fit over
the engine.
11) Remove the dummy cowl and cut away the area that you have marked. We suggest cutting away less than
you think at first and expanding the cut out area in small incremental steps. Repeat this trial and error process
until the dummy cowl can be installed with rear edge of the dummy cowl aligned with the forward edge of the
line of tape onthe fuselage. You will have to repeat this process numerous times and we recommend working
in small steps. If you overdue a cut, use masking tape to fill in the over cut area.
12) Once you can install the dummy cowl over the engine, remove the dummy cowl and install the the carbu-
retor back on the engine.
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