Tips and notes
F X - 4 0
The following solution has proved highly effective in practice:
Mount the aerial on a hardwood former inside the fuselage,
and run it through a hole of around 10 mm Ø in the fuselage.
Insulate the aerial where it exits the fuselage with a piece of
heat-shrink sleeving.
20.3 INSTALLING THE RECEIVER
• When positioning the receiver, please apply the principles
as described above.
• Wherever possible, do not position any other electronic
components in the immediate vicinity of the receiver.
• The usual practice of ‘stacking electronic units on top of
one another’ should be avoided as far as possible.
• We strongly recommend the use of low-resistance NC or
NiMH batteries as the receiver power supply.
• Avoid using pulsed BEC systems as the receiver power
supply; these “frequency generators” produce a powerful,
constantly changing frequency spectrum, which is then
passed directly to the receiver via the connecting lead. As
the load and voltage of these systems are constantly fluctu-
ating, they often do not constitute an adequate receiver
power supply. The current drain of synthesizer receivers is
generally high, and they are affected particularly badly by
this problem.
• Speed controllers for relatively high cell-count batteries
usually do not feature a BEC system for the receiver power
supply, but still incorporate an “internal” BEC system for
powering the speed controller electronics, and this opera-
tes on the same principle; it just works at lower power.
Once again the receiver connection is the direct route from
the power source to the receiver. We recommend using a
suppressor filter, No. F 1413, to keep this form of interfe-
rence away from the receiver. Some other filters only feature
a ferrite ring, but the Futaba suppressor unit also filters the
input signal using a capacitor / resistor combination.
• Different receiver types (FM, PCM 1024, PCM 2048 (G3))
also tend to respond unpredictably when connected to
auxiliary electronic modules such as glowplug energizers,
turbine control units, telemetry systems, GPS, etc. If you
experience problems, once again we recommend that you
try using the suppressor filter, No. F 1413, as a de-coupling
measure.
20.4 PRECAUTIONS IN THE MODEL
To avoid the build-up of static charges in your model, please
take the following measures:
• Helicopters:
• Connect the tail boom to the chassis using an earthing
strap. If your model features a toothed belt tail rotor drive,
attach a “copper brush” in order to dissipate the charged
energy from the toothed belt. You may also find it necessary
to connect the toothed belt pulleys to the chassis using an
electrically conductive link.
• In most electric helicopters it is necessary to connect the
tail boom electrically to the motor case.
• If your model helicopter features CFRP / GRP blades and a
carbon fibre tail boom, massive static charges may be
generated at high rotor speeds, especially in atmospheric
conditions of low humidity. To avoid this, the tail rotor gear-
box should be connected electrically right through to the
main rotor shaft. The use of anti-static sprays (e.g. Kontakt
Chemi) has also proved effective.
• Turbines:
• Connect the turbine shield plate using an earth strap to
avoid the build-up of static charges.
• Always fit a separate suppressor filter, No. F 1413, to the
turbine ECU.
• Fast-flying models made of GRP are particularly suscepti-
ble to the build-up of static charges (approx. 40,000 Volts)
due to high airspeeds - especially when aerial humidity is
low. On such models all GRP components with an area lar-
ger than about 10 cmÇ should be inter-connected using a
conductive link.
• Any other connections mounted on the outside of the fuse-
lage (e.g. fuel filler nipples etc.) should also be connected to
each other using conductive materials, to avoid static char-
ges. Such charges can cause fuel cut-off valves to be trig-
gered via the fuel line.
• Undercarriage wheels can also provoke static charge pro-
blems, and should therefore be fitted with copper brushes.
20.5 SERVO LEADS
When deploying servo leads, please ensure that they are not
under any mechanical strain and are not kinked or bent tightly,
as this might cause them to fracture over time. Make sure
there are no sharp edges which might damage the cable insu-
lation. All connectors must be firmly fitted and secure. When
disconnecting servo plugs, pull on the plastic housings - not
on the wires.
Servo leads should not just be left trailing loosely inside the
fuselage; it is far better to attach them neatly to, say, the fuse-
lage side or the chassis using adhesive tape or cable ties. It is
not permissible for modifications of any nature to be made to
the receiving system components. Avoid reversed polarity and
short-circuits of all kinds, as the electronics are not protected
against such errors.
20.6 SERVO SUPPRESSOR FILTERS
If you wish to use long servo leads or extension leads, please
note that interference may be picked up via the servo leads.
Where servo cables are longer than two normal leads (approx.
50 cm), you should at least use twisted cables (No. F 1452).
Even better: use suppressor filters, No. F 1413.
20.7 ELECTRIC MOTORS
All conventional electric
motors in RC models must
be effectively suppressed,
otherwise the sparks which
are generated between the
armature and the carbon
brushes when the motor is
running will have a serious
adverse effect on the radio
control system, and cause
interference. We recom-
mend robbe suppressor filters, No. 8306, 8307 or a set of sup-
pressor capacitors, No. 4008. Each electric motor in the model
must be suppressed individually as shown in the diagram.
If your model features brushless motors and speed controllers,
these should be connected to the receiver via a suppressor fil-
ter, F 1413.
20.8
ELECTRONIC IGNITION SYSTEMS
The ignition systems of spark-ignition petrol engines can also
generate interference, which has an adverse effect on the
99
47 nF
100 nF
Electric
motor
Connec-
tions
100 nF
