Multiplex DG - 300 Bauanleitung Seite 31

The airbrake lever now has to be set upright; this is achieved by
m0ving the mechanism towards the wing root. Thread the steel rod
into place, so that it is located under the lorwardjacing pins in the
lever. This is absolutely essential if the brake is to work efficiently.
When the brake is retracted,
these pins hold the rod in position. Pass
the rod into the bowden cable outer and connect the quicklink t0 the
lug on the actuator. Check that the unit works correctly.
Screw the bottom blade 43 in place first, followed by the top blade 44,
using the screws 45. This must be done carefully, taking particular
care to engage the fine flange on the head of the screw in the blade.
This ensures that the brake works perfectly, with no jamming. You will
need a screwdriver with an undamaged
blade tip ol the correct size to
turn this screw, because of its thin head; you will also need to work
very carefully. Please take care also that the blades do not get bent;
straighten them if necessary.
Check that the airbrakes function smoothly, then cut the brake
capping strip 39 to length. Trim it to fit neatly, and glue it on the brake
using contact cement. We advise against using 5-minute epoxy here,
as this may result in the brake becoming
stuck, with resultant severe
damage to the entire wing. Sand the airbrake cap to lollow the wing
section, using no more than moderate pressure.
Because the blades
are screwed in place, the brakes can be unscrewed
when necessary.
This may well prove important when linishing the model. Neverthe-
less, take great care in the operation,
and never use force.
Wing ioiner system
The next stage involves gluing the wing joiner blades and the locating
pins 38 into the wings. As there may be a smallam0unt of play in the
blade sockets in the wings, the job is best carried out in connection
with the fuselage.
Each joiner blade must extend to the opposite side of the fuselage.
Mask ofl the wing root lairing and the area around it, to avoid soiling
the surface with resin, and cut through the tape for the blade and the
locating pin. lilask off the wing also, wrapping wide tape right round
lhe root. The wing, blade, pin and fuselage are first assembled
"dry" to
check that they lit.
Mix up slow-setting
epoxy, apply plenty of resin to the inside ol the
joiner blade sockets, and distribute it thoroughly with the aid of a
length of wire. This is an easy job it the edge ol the socket is cut at an
angle all round, using a sharp knife. The result is a bowl-shaped
deDresst0n.
De-grease
the joiner blade and pin, and rub them down lightly where
they are to be glued. Slide the blade and pin into the wing, and remove
excess resin as it is squeezed
out. Fit the wing.onto the fuselage,
and
align the wing and fuselage root fairing. The luselage is now laid on its
side and left with the wing vertical until the resin has cured. Check at
intervals that the root fairing runs smoothly into the wing root; this is of
the utmost importance
for the llight performance
of the model. Repeat
the procedure
for the other wing panel.
Drill 3 m.m 0 holes for the bowden cables and retaining pin in the r00t
rib 37, and cut the slot for the wing joiner blade. ll you wish to tit
ballast tubes, cut out the hole where marked.
For carrying ballast we recommend
hard paper tubes (see the section
on 'Flying with ballast" at the end 0f the building instructions).
The
tubes are glued in place after the root ribs have been attached to the
wings. Lead ballast in the form ol rods, and the matching hard paper
tubes, are included in the Multiplex accessory range, and can be
obtained from your dealer (lead ballast order No. 71 2760, hard paper
tube Order N0.71 2762\.
The leading edge 0f the wings of the DG 300 must form a straight line
at right-angles to the luselage centreline.
lt is essential to check that
this is the case before lltting the root ribs, as the various formers and
plates which have been litted in the luselage may have distorted it
slightly.
Fit the lvings and sight along their leading edges. A useful aid is to
attach a thread tightly from wingtip to wingtip. Check also thal the
thread is at right angles to the fuselage centreline
(moulding
seam). lf
you find discrepancies,
do not sand back the root rib; it is much easier
to use packing instead. Glue small pieces ol scrap at either end of the
root rib until the angle is correct. Any gaps which result are filled later.
Fuselage / wing transition
The procedure described below ensures that the wing - luselage
transition is neat and accurate.
The root ribs 37 are supplied about 1 m.m. oversize; stick them to the
fuselage wing root fairings in the correct position using small pieces of
double-sided taoe.
Caulion: d0 not glue the root ribs to the wingsl
Plug the wings into the luselage to check that the root ribs are
correctly positioned. Carefully mask off the root area of the wing and
the wing r00t fairing on the fuselage using tape, to avoid soiling with
resin.
Apply 5-minute epoxy over the entire surlace ol the wing root, taking
care that none gets onto the projecting ends ol the bowden cables. Fit
the wings onto the fuselage and press them firmly into place, remov-
ing excess glue as it is squeezed out. Allow the joint to cure completely
(wait at least 2 hours). Do not be in too much ot a hurry to remove the
wings.
Remove the wings, prising them off with a thin, sharp knife if
necessary. Do not use lorce!
Sand the root ribs to follow the wing prolile and the wing root fairing,
checking repeatedly by fitting the wings on the fuselage. Any gap
between rib and wing root can now be filled and rubbed down.
ll you have kept to these instructions
explicitly, you will now have a
perfect fuselage - wing transition.
This improves the model's appeaF
anc€ greatly, but is also important in terms of good flying characteristics.
There may be a slight depression
on the top and bottom of the wing
root area where the subspars are located; this is a result ol the
manufacturing
process. Normally this cannot be seen, but can iust be
lelt with the hand. lf there should be such a depression,
it can be filled
at this stage and sanded back to profile. Take care here not to sand
into the wing skin; this would seriously weaken the wing.
The towhook is located 50 m.m. aft of the wing root leading edge.
Place the fuselage on a flat surface, and measure and mark a point 50
m.m. behind the wing root leading edge. Using a square, transler this
point downwards,
and in towards the bottom of the fuselage. lrark the
point 0n the fuselage,
and drill a 3 m.m. 0 hole exactly central (on the
seam). Mask off the hole on the outside, then glue the towhook block
40 inside the tuselage,
centrally over the hole, aligned parallel with the
fuselage centreline, using slow-setting epoxy. When the resin has
cured the 3 m.m.0 hole can be redrilled through the fuselage, but the
hole in the block itsell should only be 1.5 m.m. 0. Screw the towhook
into the block, and lile otf any burr on its end.
l{ole: lf you are fitting a retractable undercarriage
or a fixed wheel, the
towhook can be installed otfset lrom centre. The result is a slightly
greater tendency to stall t0 the opposite side during a tow launch from
a riseotf-ground take-otf. However, by holding 0n opposite rudder
and using a little care, this problem can easily be overcome.
During
the climb the offset 0f the t0wh00k is virtually unnoticeable.
The basic airframe of your DG 300 Elan is now complete.
Covering and palnting
The white-pigmented luselage ol the DG 300 does not need to be
painted. ll you wish to apply decorations, the areas to be painted
should be masked out with adhesive tape, rubbed down lightly with
400 grade wetand-dry paper, then painted with enamel or cellulose
paint, brushed or sprayed. Remove the masking tape when the paint is
dry. A white band about I m.m. wide should be painted round lhe
edge of the canopy. Mask otf the canopy with tape prior to palnting,