Jabiru J450, Руководство конструктора, Страница: 80 / 343

Jabiru J450 Constructors Manual
Pre-Paint>Fuselage>Fit windscreen
Tuesday, April 6, 2010 80 of 343
Drill the screw holes
With the windscreen still held firmly in place by the tape, the next step is to drill a series of
11/64” holes around the perimeter at the positions shown above. Note that 11/64” is slightly
bigger than the screws – this is to make sure that the threads will not bind in the holes and
possibly chip or break the Perspex.
Drill slowly with a blunt drill bit and don‟t lean on the drill - let the bit do the work.
The holes are drilled well in from the edge of the Perspex at a point where they just miss the
¼” foam tape – this gives the maximum amount of „meat‟ for the screws to grab. Note that the
bulk of the structural strength is provided by the flock: the main purpose of the screws is to
hold the windscreen firmly and accurately in place while the flock cures.
Start by drilling at each corner, then drill halfway between each corner and then drill halfway
between those holes until you have the holes as shown above and on the previous page.
Once all of the holes have been drilled they will each need to be countersunk to a depth where
the head of each countersunk M4 x 12 screw will be just below the surface of the Perspex.
Prepare the windscreen
Remove the windscreen carefully and clean away any burrs from around the holes and blow
away any dust and debris from the joggle.
Place the windscreen face down on the bubble wrap
packing material, taking care not to allow anything to
scratch the surface, and sand around the entire inside
edge with emery tape – roughen to a point level with the
inside of the bolt holes.
By holding the emery tape as shown you can use your
finger to control the width of the sanded area.
When the sanding is complete blow away the dust and
then use a clean soft cloth and wipe right around the
windscreen. Do not use any cleaning agents.