Radio
Accessories
The following is a list of some of the more
common accessories that are available for radio systems. Again, some of these are
for aircraft radios:
Aileron Extension — The Aileron
Extension (also known as a servo extension) is a cable with connectors on either end which
goes between the receiver and a servo. This allows the servo to be placed at a greater
distance from the receiver than the cable that comes on the servo will allow. It also
permits easier removal of a wing when the servo that controls the aileron is mounted in
the wing and the receiver is in the fuselage (which is usually the case). One aileron
extension is usually included with a radio system of four or more channels. Aileron
Extensions of various lengths are available from different manufacturers. Please note:
long aileron extensions can sometimes cause radio interference problems unless "noise
traps" are used.
Dual Aileron Extension or Y-Harness
— The Y-Harness is a cable which plugs into a single channel in a receiver and two
servos. This allows both servos to be operated from the same channel.
Noise Traps — A Noise Trap is a
small electronic device which is wired into a long servo extension to reduce radio
interference and to boost the control signal going to the servo. These are recommended for
use where long servo leads are necessary.
Switch Harness — The switch
harness is mounted in your model and it connects between your receiver and the NiCad
battery pack. It provides a power ON/OFF switch to the radio in your model and it also
allows your charger to be connected to your model's battery pack for charging.
Frequency Flag — The frequency
flag is a marker that is mounted on your transmitter to indicate what frequency your
system is operating on to alert other modelers so as not to cause interference. See the
section on frequencies below for more information on radio frequencies.
Servo Trays — A Servo Tray is a
plastic tray which facilitates mounting your servos easily in your model. The tray is
molded to hold your servos securely and ensure positive control to your control surfaces.
Different trays may hold anywhere from one to four servos and are shaped for different
uses and servo positions in your model. |
|
Servo Control Arms — Servo Control Arms are the plastic output
horns which are mounted to the output shaft on your servos. These come in various sizes
and styles for different control applications. Most servos will come with an assortment of
arms so you can customize to your own specific control needs.
Frequencies — As mentioned
earlier, there are different frequencies used for controlling aircraft and surface models.
Government has allotted one aircraft frequency band (72 MHz) and one surface vehicle band
(75 MHz) for use in controlling models. The separation is for public safety. Each band has
quite a number of individual frequencies. In addition, some equipment may be available on
27 MHz which is the CB band or on 50 and 53 MHz which is for Amateur Radio operators and a
Radio Amateur's operating license is required to use equipment on these frequencies.
Now, Surface Radios
Radios used for surface models (75
MHz) generally have from 2 to 4 channels with 2 channel units being the most popular. One
channel would be for the steering of the model while the other would be for control of the
speed and direction (forward or reverse) of the model. Two stick radios are
quite comfortable in controlling scale surface ships and boats, although you
could use one of the pistol grip type radios which is ergonomically easier when
controlling cars and boats.
Regardless of the manufacturer, standard
servos come with about 40 ounce/inch of torque with a transition time of around .20
seconds. It is usually good enough to handle the steering duties of most scale ships and
boats. You may want to use a high torque or heavy duty servo for tugs and boats
that use a Z-Drive (this unit has a propeller that turns as a rudder along with providing
thrust). Some systems come with an electronic speed control that work with stock
unmodified motors. So this radio system is great for any ship kit that use two
standard servos.
Remember if you plan to use an electronic
speed control in your boat, you buy a system that has only one standard servo. This
saves you money by not having to buy a servo you do not need. Or you could buy a
system that has one servo and an ESC included.
|
