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- What servos connect to what connections in the RX (Radio
Many people get confused when trying to connect the
Radio receiver in their electric powered helicopters, and this is quite
understandable as the documentation is usually less than helpful to
those that do not understood it all.
So this Tip and Trick will try to cut through the
jargon and let you now how to work out the connections on most types of
One of the first areas people don't understand is how
there are TWO AILERON SERVOS. Well, one one side they are called
AILERON, but the other side is not called that at all, it is commonly
known as PITCH. However, very few RX have a PITCH connection, and
you need to use the AUX1 connection.
Also, some RX units have names for the connections,
others use numbers alone, which is even harder to understand.
So let's look first at a very common 6 channel receiver, the one
provided by ESKY for the Belt CP. You can see below that it uses
numbering, starting from 1 and going through to 6 with an additional B
connection at the far end.
||The Esky 6 channel Rx, which uses
numbering to identify the channels. NB - MOST RX's use the
same numbers to identify the same channels.
In this case we have Channels 1-6 + a B
|This is an older NEC 7 channel
receiver, and you may have already noticed that it has a Batter
channel at the left end, so yes, you were right, that is exactly
what the "B" means on the Esky RX.
|So, by looking at the
NEC RX (above right), we can see quite easily what the various
channels re for on BOTH RX's.
Aileron (NB - maybe the left or right servo)
GEAR (often used for gyro control in helicopters)
Auxiliary 1 (Used as Pitch, or in other words, the OTHER
Auxiliary 2 (Spare for helicopters)
Battery - only used if you use an board 4.8V battery
pack to power the Radio equipment
|So, now you
can hopefully see the correlation between numbers and
actual words. Almost ALL RX's will use this same
channel layout on their RX's.
Equally important to know about is the
way around the connections should be made. The servo
wires have either Red, Black and white wires, or Orange,
Brown and yellow which corresponds to the previous
wiring colour directly. In both cases, the white or
yellow leads are the SIGNAL lead.
All connections to the RX MUST HAVE
THE CONNECTIONS THE SAME WAY AROUND, so that the white
lead is always the same side. Although not
guaranteed, most RX's expect the white signal lead
to be on the logical top of each connection
The Black and red wires are the power,
and in fact, these two pins are connected right across
the RX internally, so as long as you get the wire from
the ESC the right way around, ALL other connectors will
immediately have power on them.
So, as far as electric powered helicopters are
THROTTLE channel is where you plug the 3 wire
lead in from the ESC (Electronic Speed Controller).
AILERON Channel is where one or other of the
aileron servos are connected. This can vary, so it is often a
matter of trial and error to see which is correct for which
servo. If the swash plate moves the wrong way when you
move the cyclic stick left and right, switch the connections
between channel 2 and channel 6.
ELEVATOR Channel is where you plug in the 3
wire lead from the elevator servo
RUDDER Channel is where you plug in the 3 wire
lead from the rudder servo, or more commonly, the lead from the
gyro, and then connecting the rudder servo to the connector
provided on the gyro so that the gyro is in circuit with the
GEAR Channel is of no real use to many
helicopters, and is almost universally used to control the gain
of the gyro, which switches it between RATE mode and HH (Heading
Hold) modes. Quite often you will find this is just a single
wire connection that comes from the gyro, and the wire must go
into the signal channel in the RX. You can use a different
channel on computer radios if you wish by programming your
selection in the TX.
AUXILIARY 1 handles the OTHER AILERON Channel,
together with Channel 1.
AUXILIARY 2 is a usually a spare Channel if
you have it. Some expensive radios may have even more AUX
Channels, but these are always programmed for use in the Radio
BATTERY is rarely used with
electric helicopters, as we use the main LIPO battery for all
our power requirements via the ESC. However, those flying
nitro and gasser helicopters will use this to provide the power
to the radio system and servos as they will not have a Lipo or
I HOPE THIS LETS YOU UNDERSTAND HOW TO
RADIO SYSTEM TOGETHER IN YOUR HELICOPTER QUICKLY AND EASILY