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Jabiru J450 Constructors Manual
Pre-Paint>Fuselage>Firewall forward>Firewall fittings
Tuesday, April 6, 2010
48 of 343
Pre-Paint>Fuselage>Firewall forward>Firewall fittings
General:
This task requires the drilling of several holes through the stainless steel firewall. Stainless
steel is hard, and the best way to drill it is to use very sharp drill bits and drill very slowly:
drill too fast and your drill bit will very quickly become blunt and the stainless will work-
harden as well. For the larger holes you will need a hole saw and a few drops of cutting oil on
the teeth will make the cutting easier, once again using a slow speed.
Materials required:
Card #‟s J10
‘Firewall’
, J11 „
Fuel components’
, J25 „
Cabin heater’
, Dow Corning sealant
Air box and cable collars
The air box needs to have a small amount ground out to allow for the cable collar: mark and
remove the area indicated in the photo above left. Position the air box so that it sits flat on the
firewall just above the upper bend, then measure in 280mm from the left hand edge of the
firewall to the left hand main side of the air box. Check that the air box is level and then fix it
in place temporarily with a strip of cloth tape along the top edge.
With the air box held in place, make a mark directly behind the cable clamp as shown.
Remove the air box and drill a 22mm hole through the firewall for the cable collar then fit the
cable collar with 6G stainless steel screws (drill 1/8” holes through the firewall plate only for
these screws, they will self-tap into the plywood firewall).
Apply a bead of the Dow Corning sealant around the mounting surface of the air box and fix
it in place with 8 x 5/32 pop rivets, 1 on each corner and 1 at top and bottom centre, with a
washer on each side of each rivet (rivets arrowed in red: left hand side shown above, right
hand side shown on the next page). Apply extra sealant around the cable collar so that there is
a good seal with no possibility of air leaks. Wipe away any excess sealant with a clean cloth.
280mm