25
Hangar 9 Christen Eagle II 90 ARF
3. With the spinner backplate tight against the engine drive
washer, position the cowl so there is a 1/16-inch (1.5mm) gap
between the cowl and spinner backplate. Make sure the gap is
even and that the cowl is aligned with the backplate.
4. Use a pencil to mark the locations on the cowl
mounting blocks.
Using a small piece of masking tape
on the blocks before installing the cowl
will make it easier to see the marks.
It may be necessary to cut an opening in
the cowl to clear the head of the engine or valve
covers, depending on your choice of engines.
5. Remove the spinner backplate and cowl. Use a drill
and 5/32-inch (2mm) drill bit to drill the holes in the cowl
mounting blocks for the cowl mounting screws.
6. Use a #1 Phillips screwdriver to thread an M3 x 8 self-
tapping screw in each hole. Remove the screw, then apply 2–3
drops of thin CA in each hole to harden the surrounding wood.
The following steps are only necessary if your are
installing a glow engine in your aircraft. If you have
elected to install the EP option, skip to Step 13.
7. Use hobby scissors and a rotary tool with a sanding
drum to remove material from the bottom of the cowl.
The opening should be 4
1
/
8
inches (105mm) in width and
be 3
1
/
2
inches (90mm) forward of the rear edge of the
cowling to provide enough area for air to pass over the
engine for cooling.
8. Use a hobby knife with a #11 blade and a rotary tool
with a sanding drum to cut a 1/2-inch (13mm) wide opening
from the painted air inlet for air flow into the cowl.
