Multiplex GEMINI Notice De Construction page 24

The fuselage nose is designed to be sanded down to line up
with the spinner, using sharp paper and a sanding block, but
you should not do this until you have carefully determined the
correct motor thrustline through test-flying, as this affects the
position of the spinner.
26. Receiving system components
1. The motor is already installed
2. The speed controller fits behind the motor, suspended on its
cables
3. Install the 2100 mAh LiPo battery in the battery compartment
aft of the motor, adjust its position to obtain the correct Centre of
Gravity, then secure it with Velcro tape.
4. Stow the receiver and cables in the space below the cabin,
and hold them in place with Velcro.
Velcro tape 20 + 21 is supplied in the kit to hold these parts in
place.
27. CG
Concider the CG right from beginning with the rc-assembling.
Especially if you're using the standard-powerset ballast in
front end is needed to reach the right CG. The CG should be
75 to 85 mm from the front-edge of the upper wing. Look for
the wingspar for orientation. The model should be balanced
horizontal, not with „nose slightly down" like often mentioned.
Fig. 33.
28. Initial test-run
All the radio control components are installed and connected.
Check the base settings of the control surface travels and the
direction of servo rotation. Ensure that the hinges are free-moving.
Check the direction of rotation of the motor shaft, and reverse it if
necessary.
29. Fitting the propeller
Assemble and install the propeller as shown in Fig. 32. The
propeller driver 38 doubles up as the mounting for the EPP
spinner 18.
30. Model settings (guideline only):
CG:
Longitudinal dihedral:
Downthrust:
Sidethrust:
31. Control surface travels:
Measured at the widest point of the control surfaces
Ailerons:
Elevator:
Rudder:
Exponential:
32. Test-flying:
Centre of Gravity
Start by balancing the model within the stated range. Once you
have test-flown the model, you can fine-tune the setting as follows:
fly straight and level at half-throttle, and roll the model inverted. If
you now have to apply a great deal of "down" to hold level flight,
the model is nose-heavy; the CG must be shifted further aft. If the
machine climbs whilst inverted, without requiring elevator
correction, the CG is too far aft. When balanced correctly, the
model will require slight down-elevator for level inverted flight.
Correcting straight and level flight:
First the static balance: support the model by the spinner and
the rudder: with the fuselage level, the wings should remain
horizontal. If not, add ballast to the lighter wingtips.
On the next flight, fly the aeroplane at minimum throttle (just
24
75 mm (top wing)
top -1°, bottom +1°
0°
2 - 4° (right)
16/12 mm +/-
12/10 mm +/-
20 mm L/R
ailerons 30%
enough power to keep the model in the air), keep it straight and
level, and adjust the trims for straight flight. Now switch to inverted
and check the straight flying characteristics. If necessary, adjust
the wingtip ballast after landing the model.
Sidethrust:
Apply full throttle and fly the model straight and level past yourself
before pulling up into a vertical climb. When ascending vertically
the model should not exhibit any tendency to veer off to right or
left. If this is not the case, adjust the sidethrust to correct the
fault. Repeat the test several times, as any sidewind will tend to
falsify the model's track.
Downthrust:
Apply full throttle and fly the model straight and level until it is
level with you, so that you have a clear view of the model from
one side. Pull the aircraft up into a vertical climb: it should
continue to climb vertically, and not fall away forward or back. If
this is not the case, adjust the motor downthrust to correct the
fault.
After these tests you may find it necessary to repeat the CG
tests.
Aileron differential:
Fly three or four rolls to the right at half-throttle; if the Gemini
veers to the right during this manoeuvre, you need to increase
the aileron differential. If it veers to the left, i.e. against the direction
of rolling, you should reduce the aileron differential.
33. Gilding the lily - applying the decals
The kit is supplied with a multi-colour decal sheet, part 1. Cut out
the individual name placards and emblems and apply them to
the model in the positions shown in the kit box illustration, or in
another arrangement which you find pleasing.
34. Safety
Safety is the First Commandment when flying any model aircraft.
Third party insurance should be considered a basic essential. If
you join a model club suitable cover will usually be available
through the organisation. It is your personal responsibility to
ensure that your insurance is adequate for the type of model
(powered model aircraft).
Make it your job to keep your models and your radio control
system in perfect order at all times. Check the correct charging
procedure for the batteries used in your RC set. Make use of all
sensible safety measures and precautions which are advised
for your system. An excellent source of practical accessories is
the MULTIPLEX main catalogue, as our products are designed
and manufactured exclusively by practising modellers for other
practising modellers.
Always fly with a responsible attitude. You may think that flying
low over other people's heads is proof of your piloting skill; others
know better. The real expert does not need to prove himself in
such childish ways. Let other pilots know that this is what you
think too. Always fly in such a way that you do not endanger
yourself or others. Bear in mind that even the best RC system in
the world is subject to outside interference. No matter how many
years of accident-free flying you have under your belt, you have
no idea what will happen in the next minute.
We - the MULTIPLEX team - wish you many hours of pleasure in
building and flying your new model. Happy landings!
MULTIPLEX Modellsport GmbH & Co. KG
Model Development Dept.
Klaus Michler