Multiplex Alpina 4001 ELEKTRO Notice De Construction page 18

Carbon canopy
This canopy provides an eye-catching focal point for the
model, and reduces work on the cabin area to a minimum.
There is no need to trial-fit and trim the canopy, as required
with standard vacuum-moulded versions.
The canopy 4 is held on the fuselage at the front using a
steel pin 61. At the rear a flat GRP strip 62 is used, acting
as a retaining spring.
Fix the GRP spring to the inside of the canopy as shown
in Fig. 6, leaving it projecting by 10 mm at the rear end of
the canopy. Glue it in place permanently using thickened
epoxy and two layers of glass cloth (approx. 100 g/dm²).The
GRP spring should be glued over a length of 50 to 60 mm.
Don't forget to roughen the joint surfaces using 80-grit
abrasive paper beforehand.
Glue the locating peg 61 to the channeled strip 15 using
thickened epoxy, leaving it projecting by about 13 mm.
Allow the epoxy to set hard, then glue the channeled strip
to the inside of the canopy. Position the strip about 18 mm
aft of the front edge of the canopy.
To make up the difference in thickness between the
vacuum-moulded canopy / frame and the carbon canopy,
strips of self-adhesive Velcro tape 63 (loop) are applied to
the inside of the carbon canopy, as shown in Fig. 6.
[Fig. 6]
Cut down the centre of the Velcro loop strips 63 with a pair
of scissors.
Apply the strips to the inside of the canopy as shown: one
strip at the lower canopy edge front and rear on both sides.
The fuselage canopy recess now has to be prepared to
accept the front locating peg. File a notch in the flange
using a round file and adjust it gradually until the canopy
is a perfect fit.
Caution: work slowly here, as it is very easy to file away too
much material.
Wing / fuselage fit
The Alpina 4001 ELEKTRO features a free-floating wing
joiner system.
This means that the wing joiner does not touch the
fuselage. The openings in the fuselage for the spar joiner
should be about 1.5 mm larger all round than the joiner
itself. File the holes out if necessary to provide proper
clearance.
This method of attaching the wings is standard practice in
full-size aircraft building, and has already proved excellent
in many MULTIPLEX models.
The wing joiner 48 takes the form of an extremely strong
12 mm Ø spring steel rod.
The fuselage is suspended between the wings on four
pins. Don't worry about their size - the pins have a total
sheer strength of more than one ton! Please work carefully
when drilling the pin holes as they determine the accuracy
of the wing location.
[Fig. 7]
[glider version only]
Using small screw-clamps carefully fix small pieces of 3
18
mm scrap plywood to the top and bottom surfaces of the
wing at the leading and trailing edges to act as stop pieces
when positioning the wing against the root fairing. These
locating pieces should overlap the fuselage root fairing by
about 3 mm at the top only.
Position one wing carefully (at leading edge and trailing
edge), tape it in place, and mark the position of the pin
holes on the wing root rib working through the fuselage
from the opposite side, using a length of 3 mm Ø steel rod
filed to a point. Repeat the procedure with the other wing.
Drill the holes in the root ribs using a 3 mm twist drill.
Remember to take the dihedral into account; the holes
should be drilled parallel to the wing joiner. The locating
pins 49 can be glued in place once both wing panels have
been prepared to this stage. Round off one end of the pins
and sand them thoroughly where they are to be glued.
Apply mould-release wax (ordinary wax polish will do) to
the fuselage at the wing root position, and glue the pins in
place using slow-setting epoxy - UHU-Plus or similar.
About half the length of the pins must project out of the wing
roots, and please note that it makes for easier assembly
at the flying field if the pins are of different length front and
rear. Align the fuselage and wings carefully, tape them
together and leave the resin to cure overnight. Remove the
screw clamps and scrap wood.
We maintain tight manufacturing tolerances, but
nevertheless there is always a chance of minor
discrepancies in the fit between the wing and the fuselage
root fairing. Any minor gaps and slight mis-fits are easily
corrected.
Installing the all-moving tailplane bearing
The tailplane bearing exploits technology which has proved
to be an outstanding success in many MULTIPLEX models
over a number of years. This professional solution to an
old problem is based on precision-made machined parts,
accurate to 1/100 mm, and this is the system used in the
Alpina 4001 ELEKTRO. The high-quality bearing prevents
the tailplane wobbling in the wind as a result of slop, and
also provides a really strong, load-bearing joint between
fuselage and tailplane. It represents the final, professional
solution to the problem of bonding the bearing to the
fuselage.
[Fig. 8]
1. Screw one of the two tailplane bearing nuts 56 on the
threaded pivot bush 57, set it flush with the end and lock
it in place with a drop of cyano.
2. Open up the holes for the tailplane bearing in the fin and
clean them up on the inside of the moulding. Carefully
roughen up the joint surfaces inside the 12 mm Ø external
recesses in the fin.
3. Open up the curved slots for the rear tailplane joiner rod.
4. Solder a clevis 40 to the steel elevator pushrod 80 (1.3
mm Ø x 1400 mm).
5. Prepare the 3 mm Ø steel rods 58 which form the
tailplane joiners. Round the ends off carefully and shorten
them if necessary. Connect the clevis 40 to the third hole
from the bottom of the tailplane crank 54 and slip the
pushrod into the snake outer from the tail end. Temporarily