RADIO CONTROL TRANSMITTER, RECEIVER AND SERVOS
The radio control transmitter, receiver and servos (RC system) allows the driver (you !) to be remotely connected to the vehicle you are driving. In essence, this connection is enabled through radio signals carrying commands emitted by the transmitter, and which is interpreted by the receiver and which are then sent to the servo or ESC as instructions for certain operations.
RC cars will require radio systems with a minimum of 2-channels, one each for throttle and steering. Additional channels are mainly useful only because the additional channel sockets in the receivers can be used as a power source for other equipment such as a cooling fan or transponders for lap-timing.
It is important to note that hobby-grade RC cars should use proportional radio systems, meaning that the servo or ESC will only move as much as the transmitter controls are moved. This allows you to have more precise control over the operation of your vehicle.
The main components of a RC system are the following:
Transmitter – these are held in the hands of the driver and can be either pistol grip or stick type transmitters.
More common these days are the pistol grip transmitters which are held like a hand-gun, where the trigger controls the trigger, while a wheel controls the steering.
Stick transmitters feature at least 2 input joy-sticks which control both throttle (left joy-stick) and steering (right joy-stick).
The transmitter will also feature trims to fine-tune the controls. More sophisticated transmitters will also display telemetry data from the car such as the temperature of the equipment and motor rpms.
Most radio system these days transmit via a wireless data link over the 2.4Ghz which use direct sequence or automatic frequency hopping technologies to distribute their transmissions over a wider selection of frequencies (or in the case of frequency hopping, completely different channels) in the 2.4Ghz spectrum. These systems eliminate the interference that occurs when 2 transmitters are using the same narrow-band frequencies in older transmitters.
Receiver – mounted in the vehicle, the receiver must be connected to the transmitter via a process of “binding”. Once this is once, the receiver is able to interpret the signals sent by the transmitter, for forwarding to the servo or ESC.
Servo – in RC cars, the servo converts electrical signal into polar or linear movement. Based on the signal received, the servo will rotate it's drive shaft for some degrees, and this rotation is translated into wheel steering. For nitro-powered cars, a 2nd servo is used to control the operation of the engine.
RC car bodyshells are made of lightweight lexan. Most RTR kits come with specific pre-painted bodyshells, while hobbyists with self-build kits will prefer to choose their own bodyshells.
Bodyshells typically come in clear form, which you would then paint using specially formulated flexible paint. This is one of the areas of the hobby that many enjoy as it allows you to exercise your creativity in designing your own car livery.
Given the extreme speeds that most racing level cars reach, aerodynamics play a big part in ensuring on-track performance. Competitive racers would typically own different bodyshells with distinct aerodynamic characteristics that they would test to see what works best depending on the track layout and traction conditions. These days, many bodyshells are also designed using computational CFDs to optimize aerodynamic performance.
Now that you have the basic information on what makes up a radio control car, you are equipped to get started in this exciting hobby.
With the proliferation of webstores, it is easy for those starting in the hobby to choose their products based on pricing alone.
While price is no doubt an important consideration, the following additional aspects should also be noted:
What cars or brands do the regulars run ?
An important aspect of enjoying the hobby is having a well setup car. When you use a car platform that is popular with regulars, it is easier to get a setup that works by learning from those who have been in hobby longer.
Are spares readily available ?
Even the best drivers will crash and break parts. It is always better to have ready local access to spares that can get you back racing quickly.