Here are some terms and function that may
come across with various R/C systems.
The control stick configuration with the rudder and elevator being
controlled by the left stick while the right stick controls the throttle
The control stick configuration with the ailerons and elevator being controlled
by the right stick while the left stick controls the rudder and throttle.
The control stick configuration with the rudder and elevator being controlled
by the right stick while the left stick controls the ailerons and throttle.
This feature allows the modeller to reverse a servo's rotation direction
at the flick of a switch. Servos can be mounted in the most convenient
way without worrying about their rotation direction. The proper movement
can then be selected when the installation in the model is completed.
Dual Rates (D/R)
Dual Rate allows the modeller to choose between two different control
sensitivities. With the dual rate switch in the "OFF" position, 100% servo
throw is available for maximum control response. In some more sophisticated
systems this "OFF" position may be adjusted to provide anywhere from 30%
to 120% of normal full throw. In the "ON" position, servo throw is reduced
and the control response is effectively reduced. The amount of movement
in the Dual Rate "ON" position is usually adjustable from 30% to 100%
of total servo travel. The modeller can adjust the sensitivity of his
model to his own preferences.
Exponential Rate is where the servo movement is not directly proportional
to the amount of control stick movement. Over the first half of the stick
travel, the servo moves less than the stick. This makes control response
softer and smooths out level flight and normal flight manoeuvres. Over
the second half of the stick travel, the servo gradually catches up with
the stick throw, achieving 100% servo travel at full stick deflection
for aerobatics or troublesome situations.
Fail Safe (FS)
An Electronically programmed mechanism in most PCM radios which automatically
returns a servo or servos to neutral or a pre-set position in case of
radio malfunction or interference.
Frequently referred to as End Point Adjustment, ATV lets you independently
pre-set the maximum travel of a servo either side of neutral.
Similar to ATV, AFR allows end point adjustment independent of Dual Rate
or Exponential settings.
A radio function which allows very precise electronic centring of servos.
Direct Servo Controller
Allows full function of an aircraft's servos via an umbilical cord. This
permits adjustment of radio functions without switching on the RF portion
of a transmitter.
This radio function is similar to exponential except it uses two linear
responses to determine the servo sensitivity on the first and second half
of the control stick movements.
Electronic coupling of one channel to another. One control input will
output to two different servos and can be set up to move at different
Adds rudder control when aileron is input from the transmitter aileron
stick. This is usually fully adjustable.
Used when there is a V-Tail on the aircraft rather than the conventional
elevator and rudder. Each control surface of the V is connected to a separate
servo. Operating the elevator control stick will move both surfaces up
for back stick or both surfaces down for forward stick. Moving the rudder
control stick left will move the left surface of the V down and the right
surface up giving the left rudder response. Moving the rudder control
stick to the right will move the left surface of the V up and the right
surface down, giving the right rudder response.
Mixes the Flap and Aileron functions so that when each aileron is connected
to a separate servo (one servo plugged into the aileron channel and the
other plugged into the flap channel), the surfaces will act as both ailerons
and flaps, depending on the position of the controls.
Mixes the Elevator and Aileron functions, especially useful for delta-wing
models where the elevator and ailerons are the same control surfaces.
Each surface is connected to a separate servo (one servo plugged into
the aileron channel and the other plugged into the elevator channel),
the surfaces will act as both ailerons and elevator, depending on the
position of the controls.
Couples the Flaps and Elevators such that when the flaps are lowered,
the elevator will be automatically adjusted to prevent pitching of the
Couples the Elevators and Flaps such that when control is input to the
elevators, the flaps will move in the opposite direction. This permits
the model to perform tighter manoeuvres in the pitch attitude.
Crow Brake Mixing
Primarily used in gliders for spoiler action by mixing the flaps and ailerons.
It is necessary for the ailerons to be using separate servos, plugged
into separate channels and the flap servo to be independent of both aileron
channels. Upon applying Crow Brake Mixing, the flaps go down while both
ailerons go up.
This type of mixing is accomplished by having separate servos on each
aileron, plugging one into the aileron channel and the other into another
unused channel. The two channels can be programmed to both operate from
the aileron control stick, however the travel for each aileron may be
adjusted separately giving more deflection in one direction (usually up)
than in the other.
Dual Conversion refers to the method in which the receiver processes the
incoming signal. Generally a Dual Conversion receiver is less prone to
outside interference and is the preferred type of receiver.
The trainer system sometimes referred to as the 'Buddy Box' system allows
two transmitters of similar design to be connected together via a cord
(trainer cord) so that one transmitter may be used by an instructor and
the second one by a student when teaching to fly. The instructor simply
has to hold a switch on his transmitter to give the student's transmitter
full control. If the student gets into trouble, the instructor can release
the switch and he has full control of the model.
Snap Roll Button
This feature is found on more complex radios and is used to perform a
snap roll manoeuvres by simply pressing one button. The function is usually
programmable to give a combination of rudder, elevator and aileron control.