Operation Manual

"CPM"
control system
(HEAD
Mlx):
Abbreviation
for
Collective
Pitch lvlixing. The control sig-
nals for collective
pitch, pitch-axis
and
roll-axis are elec-
tronically
"composed"
and
sent to the servos.
Between
servos
and swashplate
there are
no mixer levers or
similar
mechanics, so
mechanical complexity
is min-
imised.
Virtual swashplate
rotation:
lf a 3-
(or
more) bladed rotor
is mounted on a swash-
plate
intended for a 2-bladed system,
then the
tilt of the
swashplate
no longer corresponds
to the
inclination of
the rotor disc, as
it is not
possible
in design terms to
locate
the mechanical
linkage to each blade of a
mul-
ti-blade
rotor at a
point
90
degrees in advance
of its
highest
point.
lf
the swashplate
control system cannot
be
rotated through
the
appropriate
angle
to match the
blade system,
the
pitch-axis
and
roll-axis servo signals
can be
mixed electronically to achieve
an apparent
(vir-
tual)
rotation ot the swashplate.
Arrangrm€d
9d
Frequency
bands, channels,
crystals
and spot
frequencies
Four
frequency bands are available
for
the
control
ot
models in the U.K.:
27
l\llqz
band
35
MHz
band
(A
und
B
band)
40
MHz
band
459 MHz band
The latter band
is used
very little
at
present;
the
PROFI
mc 3010
transmitter and
receiver are only available
on
the first three bands.
The easiest
way of
imagining frequency bands
is to
compare
them with the
wavebands on
your
radio. Think
of long
wave
(LW),
medium wave
(MW),
and so
on.
On
your
radio
you
can
probably
change
bands by
pressing
a
knob. With radio control
equipment
we
can't
do that:
the transmitter
has
an
RF module
which has to
be changed.
The receiver, on the other
hand,
must
be
swapped
for
a
new one.
A channel,
or spot frequency,
is a narrow section
of one
frequency band.
Going back
to our
radio
analogy,
a
spot
frequency
corresponds
to one radio
transmitter, or
station.
Instead ol
the frequencies themselves,
which
are diff
icult to
remember, we use standardised
channel
numbers.
The crystals
in the transmitter and
receiver determine
the
frequency and the channel.
They must therefore
be
matched to each other
with extreme
precision.
That is
whv:
Always use
genuine
MULTIPLEX crystals
in
your
MULTIPLEX radio control
equipment!
The
channel
number
is
always
printed
on
one face of
the crystal.
next to it
you
will see either
an
"S"
(Sender
=
transmitter)
or an
"E"
(Empfaenger
=
receiver).
Transmitter crystals
are enclosed
in a transparent
blue
casing, and
"normal"
receiver crystals
in a transparent
vellow one.
Caution:
Ordinary
receiver crystals
cannol
be used
with dou-
ble-suoerhet
receivers.
Double-superhets
require
special types
(DS
crys-
tals).
They are fitted
with
an
integral colourless
plas-
tic
holder
(Fig.
66).
Fig. 66
77