Jabiru J450, Руководство конструктора, Страница: 109 / 343

Jabiru J450 Constructors Manual
Pre-Paint>Fuselage>Fit cowling
Tuesday, April 6, 2010 109 of 343
Mark and cut the cowls to length
In the next 2 steps we will need to cut both cowls to length so that they will fit into the joggle.
In the factory we have a handy technique that we use to mark the cut: we run masking tape all
the way around the outside of the joggle on the fuselage with the front edge of the tape
exactly level with the step of the joggle (left photo above) and then when the cowl is in place
we run another strip of masking tape around the cowl but with back edge of the cowl tape in
line with the back edge of the fuselage tape (left photo below), so we use the width of the tape
as a way to accurately mark where to cut. ¾” masking tape is ideal for the purpose.
In the photo above left the back edge of the cowl tape is being aligned with the back edge of
the fuselage tape, while in the photo above right the cut is being made in line with the front
edge of the cowl tape. Sand any rough edges away with a long sanding block and refit the top
cowl, using the centreline mark to position the cowl at the back and checking that the front of
the cowl is still centred, then tape the top cowl into place.
The same “masking tape” technique will be used to cut the bottom cowl to length.
Drill 3 x 3/32” holes through the top cowl and into the fuselage: each hole should be 10mm in
from the edge of the cowl, with 1 on the cowl centreline and 1 each side 30mm up from the
cowl join. Temporarily fix the top cowl into place with 6G stainless steel screws.
Now that the top cowl has been positioned we can fit the bottom cowl to match it.
Line up
this edge
To mark
and cut
this edge
Back edge
of tape
Front edge of
tape exactly
level with
joggle step
Front edge of
tape exactly
level with
joggle step
Line up the back
edges of the
fuselage and cowl
tapes
Cut along the
front edge of the
cowl tape