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Jabiru J450 Constructors Manual
Pre-Paint>Fuselage>Firewall forward>Fit ram air cooling ducts
Tuesday, April 6, 2010
75 of 343
Pre-Paint>Fuselage>Firewall forward>Fit ram air cooling ducts
Objectives of this task:
In this task the ram air cooling ducts will be assembled and fitted to the engine.
The final step, where the front of the ducts are trimmed to length to match the bottom
cowling, cannot be performed until the bottom cowling has been fitted to the fuselage and so
that step is included as part of the
Fit cowling
task that follows this task.
Air enters the front of the ducts and is routed up by low air dams, through the fins on the
cylinder heads and barrels and then downwards at the rear by a pre-fitted angled baffle.
An aluminium tube directs cooling air from each duct to the nearest magneto coil.
Materials required:
Epoxy resin and AF303 glass fibre cloth (from the bag labelled “
Extra Cloth
”)
5-minute Araldite and flock
Assemble the ducts
Use a length of masking tape on the
join line at the bottom of each duct
inlet to hold the join firm and prevent
Araldite/flock from leaking through.
Mix a small batch of 5-minute
Araldite and flock and apply to the top
of each join as shown at right:
Next the front air dams will need to be cut to size. Take the length of glass fibre sheet with the
curved edge, hold it against the rear of the duct inlet with the curve towards the top rear of the
duct and mark around the bottom of the duct then cut to shape as shown above.
Tape the air dam into place. Mix a small batch of 5-minute Araldite and flock and use it to fix
the air dam into place. Leave to cure, then sand away any rough edges.
Remove the masking tape and roughen the underside of the duct and the back of the air dam.
Mix a small batch of resin and brush 2 layers of AF303 glass fibre cloth to the underside o f
each duct, covering the join line and wrapping up around the back edge of the air dam.
Leave overnight to cure.