Multiplex alpha 21 Instrucciones De Montaje página 14

Installing the receiver battery
The receiver battery is held in place in the fuselage nose
using Velcro tape (MPX # 68 3112) and foam packing or
similar. At the top fit a piece of foam rubber or styrofoam
between the fuselage and the battery to prevent it moving.
In the electric version a separate receiver battery is not
required provided that you use a suitable BEC speed
controller, as the servos and receiver are powered by the
flight battery.
In the electric version you can use a suitable BEC speed
controller, which eliminates the need for a separate receiver
battery. In this arrangement the servos and receiver are
powered by the flight battery.
However, for safety's sake we recommend the use of a
separate receiver battery, e.g. 4/600 mAh, MPX # 15 5553.
Completing the fuselage linkages
Remove any rough edges from the rudder pushrod 51 and
slip it into the bowden cable inner tube 52. Slip the inner into
the outer sleeve in the fuselage, and bend it slightly in the
desired direction if necessary. At the rudder end solder or
epoxy a clevis 36 to the pushrod (use UHU plus Endfest 300
slow-setting epoxy). Sand the end of the steel rod thoroughly
before gluing or soldering.
Connect the clevis to the rudder horn 39 and mark the
position of the horn on the rudder. Drill holes for the
retaining screws, and fix the horn in place using the spreader
plate 40 and two screws 41. Check that full rudder movement
is available to both sides, and make adjustments if necessary.
Screw a locknut 38 and a clevis 36 onto the threaded coupler
37 and connect the clevis to the servo output arm. Cut the
pushrod to the correct length at the servo end, taking into
account the depth of the coupler socket, and sand the end
thoroughly. Set the elevators to neutral and solder or epoxy
the threaded coupler to the pushrod.
The elevator linkage is based on the steel pushrod 50.
Complete it by repeating the procedure described for the
rudder linkage.
Locate the channeled rail 14 which supports the bowden
cables at the front end of the fuselage, trim it to fit and glue
it to the fuselage sides.
Final work on the fuselage
Screw the towhook 35 to the fuselage.
Slip the receiver aerial into a spare bowden cable sleeve, tie
a knot at the end and lay the tube in the fuselage tail boom.
It does not need to be fixed in place.
Tip: to draw the aerial through the tube, first glue the end
of the aerial to a length of 0.6 mm Ø spring steel wire with
a drop of cyano, then pull the wire through the sleeve.
Completing the wing
At this point you have to decide which control surfaces on
the wings are to be radio-controlled.
The wing of the alpha 21 is factory-prepared in such a way
that it is a simple matter to separate the ailerons and landing
flaps and link them to the RC system.
The ailerons and flaps can also be left in place initially if you
prefer, and linked up at a later date, i.e. after you have flown
the model for a while. The alpha 27 is designed for aileron
control from the outset.
There are two methods of slowing the model for the landing
approach:
If you have a suitable radio control system (with mixers) you
can set the ailerons to rise together to provide glide path
control. However, this type of brake is not very effective on
14
these models, and it is much better to use the landing flaps
incorporated in the inboard wing panels.
Installing the wing-mounted servos
The wings are factoroy-prepared to take the servos. The first
step is to cut away the covering film on the underside of the
wing at the servo position. Solder the end of the servo lead
(e.g. cable set, MPX # 8 52553 to a length of steel piano wire
and thread it through the holes in the wing ribs.
Place the servo (e.g. MS-X3 servo, MPX # 6 5135) in a piece of
heat-shrink sleeving and shrink the sleeve round it. Sand the
joint surface of the plastic sleeve and glue it in the wing
using 5-minute epoxy. Connect the wires as described in the
instructions supplied with the cable set, and glue the socket
to the facing rib of the wing panel. When the glue has set
hard apply a strip of tape over the socket. Wax the tape and
polish it off with a soft cloth. Now push the plug into the
socket, apply thickened 5-minute epoxy to the plug and
push the wing panels together so that the plug is glued to
the other wing panel. The servo connector now engages
automatically, and the system is simple to install and works
reliably.
Cut out the servo fairing 8 and attach it with hinge tape after
connecting and adjusting the mechanical linkage.
Fig. 13
Separating the ailerons and/or landing flaps
Separate the control surfaces from the wing by sawing
parallel to the fuselage centreline using a metal-cutting
blade to produce a fine, clean cut. Place a ruler along the
hinge line in the spanwise direction, and cut through the
connecting piece with a sharp balsa knife. Sand the hinge
line surface completely flat using a sanding block, and apply
adhesive tape to the bare wood to seal it after ironing down
any loose edges of the film covering along the hinge edge
using a film iron. The aileron or flap can now be attached to
the wing using hinge tape, MPX # 70 3205. The best method
is to apply a single strip centrally along the top pivot line,
then fold the control surface up and over before applying
a second strip on the inside of the hinge.
Fig. 14
Actuating the ailerons and/or landing flaps
The linkage to each control surface is based on a pre-formed
steel rod 42, a threaded coupler 37, a locknut 38 and a clevis
36. The connection to the control surface is by means of the
screw-fitting horns 43, spreader plates 40 and two screws 41.
If you decide to actuate the supplementary control surfaces,
the linkage components required are to be found in the
MULTIPLEX accessory range.
Fig. 15
Uncovered version: at this point the bare wooden parts
have to be covered, and for this we recommend iron-on film.
Please refer to the appendix for details of the covering
procedure, together with many useful hints and tips.
Leave the trailing edge about 1 - 1.5 mm thick and "square".
Don't round off the trailing edge, as the thicker, sharp-
edged trailing edge is almost as efficient as a razor-sharp
one, but is much more durable for general flying, especially
if film-covered.