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Jabiru J450 Constructors Manual
Pre-Paint>Fuselage>Firewall forward>Fit engine mount and engine
Tuesday, April 6, 2010
61 of 343
Pre-Paint>Fuselage>Firewall forward>Fit engine mount and engine
Objectives of this task:
In this task the engine mount will be fitted to the firewall at the top attach points only, the
engine will be attached to the engine mount, then the engine angle of incidence will be set and
finally the engine mount will be fitted to the bottom attach points on the firewall.
The engine angle of incidence is particularly important, both to the general flying qualities of
the aircraft as well as making the fitting of the cowls more straightforward, and should be set
carefully and precisely. You will need either a portable engine lifter or a few strong friends to
help you mount and position the engine in this task.
From this point on the engine will remain fitted to the fuselage.
Parts required:
Engine mount sets: AN4-20A & -31A bolts plus washers, spacers, rubber mounts ►
From Card # J10
‘Firewall’
, the 4 x 4025094 backing plates (photo below right)
From Card # J23
‘Engine’
, the washers and lock nuts in “
Engine mount hardware
”
Fit the engine mount to the firewall
Now would be a very good time to paint the engine mount! We prefer gloss black.
Drill the top engine mounting holes through the stainless steel firewall plate from the inside,
through the pre-drilled holes in the plywood firewall that you cleaned in the previous task.
Attach the engine mount to the firewall with the top (AN4-20A) bolts only: fit each bolt from
the front, through the mount, firewall, and the backing plate (shown
at right) and fit a washer and Nyloc nut. Tighten the Nyloc nut
firmly but without crushing the plywood firewall. Do not bolt the
bottom of the engine mount to the firewall at this stage; leave it
until the engine angle of incidence has been set.
Note that
the bottom centre section of the
engine mount (shown at left) rests
against
the penny washers of the top
internal brace bolts but does
not
rest
on the heads of the bolts.
Backing plate viewed from
back of firewall