same time you can open the air inlet hole in the
front of the cowling, as shown. Sand any seams
on the fuselage and cowling that might prevent it
sitting perfectly flush, and tape in position. Now
carefully wax all around the mating surfaces of
the fuselage and cowling in case you should get
some glue on there during the next steps.
With a Dremel, or similar, you can drill 2 pilot
holes for the carbon pins and tubes from inside
the fuselage - as long as you do this
before
the
landing gear mount is fitted. Remove the cowl
and enlarge the holes in the fuselage to 8mmØ
and the holes in the cowl to 6mmØ. Glue the
pins into the cowl with a little 30min. epoxy and
micro-balloons, and then wax them carefully.
Wax the inside of the short 8mm tubes carefully,
and slide them onto the pins and tape the cowl
in position again. Glue the tubes into the fuse-
lage with the same epoxy/micro mix.
Glue the 2 small milled 3mm plywood squares
(15 x 15mm) inside the cowl flanges, about
75mm from the front. Drill thru’ the centre of the
ply squares 3.2mm, and tap M4. Fit the plastic
bolts, and mark the position of the heads of the
bolts on the fuselage flanges. Reposition these
marks about 10mm forward and drill 2 holes of
9mmØ to accept the boltheads. Then mill and
file two 4mm wide slots backwards, about 10mm
long as shown. Check the fit of the cowl and
adjust as needed. When the fit is OK, glue the 2
phenolic ‘U’ shaped plates onto the inside of the
fuselage flange with a little CA. Adjust the length
of the bolts to make the cowling a snug fit, that
cannot vibrate. Glue the bolts in their final posi-
tion with a little 5 min epoxy.
Note:
Do
NOT
use CA on any plastic parts as it
makes most plastics brittle, and they might frac-
ture or split.
Finally fit an M3 blind nut into a small ply plate
(20mm x 20mm) and glue under the front flange
of the fuselage, in the centre. Drill thru’ and use
a single M3 bolt to secure the cowl, accessed
thru’ the air inlet hole. If fitting a glow engine with
a front carburettor, please check to see that the
carb and this securing bolt don’t interfere. If so,
then you can use 2 bolts about 20mm either side
of the centreline.
Composite-ARF IMPACT
10