Install The Cowl - GREAT PLANES Extra 300S ARF Instruction Manual

the three line system, you will need to route the carburetor
line to the carburetor fuel nipple and the vent and fill lines to
the front of the firewall. Glue a block of balsa to the firewall
and make a hole through it of the size of the vent tube. Slide
the vent tube through the balsa block. Plug the fill tube with
an Aluminum Plug. Make sure the fill tube is long enough so
that it can be pulled out of the cowl to fill the tank. If you use
the two tube system with the Easy Fueler Valve, the valve
needs to be installed between the carburetor and the tank in
the carburetor line.

Install the Cowl

Note: The cowl installation is similar for both the gas engine
and the glow engines option. This instruction book will
explain how to install the cowl with a glow engine installed
on the airplane. The only difference between the two
installations is the location of the holes for the carburetor
needle valves and clearance holes for the muffler tubes.
1. Find the five 5/8" x 5/8" x 7/8" [15mm x 15mm x 20mm]
hardwood blocks. Glue them on the firewall as in the
positions shown with 6-minute epoxy. Carefully sand them to
the contour of the fuselage. Use masking tape on the
MonoKote to protect it from being scratched while you are
sanding. Also sand away the fuelproofing on the firewall to
glue the blocks to the bare wood.
2. Find the remaining 1/8" x 10" [3mm x 254mm] hardwood
dowel and cut it in 1" [25mm] lengths. Drill two 1/8" [3.2mm]
holes on each cowl block into the firewall. Glue the dowels
in the holes with epoxy. This will improve the blocks ability to
withstand engine vibrations.
3. Use long paper strips as shown to mark the location
of the hardwood blocks. Tape the paper strips to the fuselage
so that they do not move during the following steps.
4. Place the cowl over the engine and push it back onto
the fuselage until the cowl ring is 1/8" [3.2mm] behind the
face of the prop washer. Install the spinner back plate and
the propeller nut. Center the cowl ring using the spinner
back plate as a reference. Tape the cowl in place.
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