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How Does a Radio Controlled Car Work?

If you are wondering how Radio Controlled Cars really work, you are in the right place. As a newbie there is a lot to learn, let me break it down for you in this article.

How does a radio-controlled car work? Radio controlled cars work by sending radio waves (electromagnetic frequencies) from the transmitter to your car’s receiver. The information is interpreted by the circuit board and is then used to direct the motor and gears. The motor converts energy from the battery or nitro fuel to mechanical energy to give the car its speed and power.

Knowing how your car functions and the different parts that make it work can end up being advantageous to even the most casual driver. When your car suddenly stops working in some capacity, knowing which parts affect that function can help you replace those broken parts with less stress and effort.

The Transmitter

Transmitters are the brains of your vehicle. They are the little controllers that you hold in your hand and allow you to tell your car whether to go left or right, forward or backward, fast or slow. Transmitters have a built-in antenna that sends the radio waves to your car.

The transmitter has a separate power source from the car—usually a battery or two. Most RC cars operate at 27 MHz (megahertz), though most RC manufactures will also have an identical vehicle that uses 49 MHz, so you can drive both vehicles at the same time.

The more advanced cars can also operate on 72 or 75 MHz frequencies. This information is important, because if you buy a replacement transmitter that operates on a different frequency, it will not work with your RC car. The frequency that your car operates with should be on the underside of your vehicle.

Transmitters come in a wide variety. Some can be very simple, single-function controllers, while others can be full-function controllers. Single-function controllers usually only have one button or lever which causes the car to go forward when pushed or backward when released.

The car only stops when it is turned off. The full-function controllers usually have six controls. The full-function controllers allow for a lot more control and range of movement. They can be directed to go any direction while going forward or reversing.

When no buttons are pushed, the car comes to a stop. For even more advanced drivers, some RC transmitters have dual joysticks that allow you even more control over your vehicle’s movements. Very basic transmitters are excellent for young children, while adults usually enjoy the more advanced controllers. However, even young children can master any transmitter with enough practice.

The transmitter contains a circuit board that houses the rest of the internal parts.  These include an antenna that sends the information to your car, a throttle that tells the car to go forward, a steering mechanism that controls the car directionally, and battery wire connections that power your transmitter.

If your batteries are fresh but your transmitter won’t turn on, your battery wires have probably come loose. The transmitter also contains a crystal. The crystal determines which radio frequency your transmitter uses. Said crystal vibrates from the current of the battery, and this creates an electromagnetic wave that sends the information through the air to the car’s receiver.

The Receiver and Circuit Board

RC cars contain a receiver (which is usually an antenna that is either external or internal) that identifies the signals that are traveling on the right frequency. These signals are then sent to the circuit board inside of the car.

The circuit board translates the radio waves from the transmitters into commands and then causes the motor to start, the wheels to turn, and controls whether the car drives forward or backward. It also controls how fast the motor spins, which gives the car its speed.

The Drivetrain

The drivetrain is the name collectively given to the wheels, axles, and gears. The axles allow the wheels to turn. Some RC cars have more than one gear setting, which can allow the car to reach higher speeds.

These can be made out of anything from low-grade plastic to metal. Obviously, the toy-grade is going to be cheaper and made out of more flimsy materials. The professional RC cars often come with metal gears, which allows for the higher torque of nitro engines and high-end brushless engines.

Power Source

The motor can be powered by either nitro fuel or batteries.

Nitro fuel has many advantages. It doesn’t take time to recharge, so you can play with your vehicle for a much longer period of time. When your fuel runs out, you just refill and you’re good to play again. A little fuel can last you for quite a while, as well.

Nitro fuel engines tend to provide real-life mechanical experience, to boot, as they tend to be more like real automobiles. Nitro engines are loud, which some people love and some people REALLY don’t, and these cars do have a rather pungent odor.

Many race tracks are indoor tracks, and RC cars with nitro engines are not allowed indoors. It is always good to check with your local racing community (either through an RC hobby store or through local RC group forums) to find out what kind of vehicles are allowed on nearby racetracks.

Electric RC cars are powered by one of several kinds of batteries. Batteries use chemical reactions to produce electricity. This electricity is transferred to the rest of the vehicle and powers it until the battery’s chemical reaction potential is spent.

There are a number of different kinds of batteries that you can use, but I recommend either Ni-MH or LiPo batteries. Ni-MH are rechargeable batteries that come either as single batteries or as a pack. Ni-MH batteries are stable, but not nearly as powerful as the LiPo battery.

They recharge in around an hour or so, but they only run for about half that time at full power. Ni-MH batteries are inexpensive and can be used in nearly every kind of electric RC car.

LiPo batteries are much more powerful and longer-lasting than Ni-MH batteries. They increase the capabilities of the vehicle they are powering, and some brushless engines that are powered by LiPo batteries are capable of reaching speeds up to and exceeding 100 mph.

However, LiPo batteries have a pretty impressive (although happily rare) downside. If punctured or damaged, LiPo batteries will begin to heat up and release all the energy they have stored in an instant.

Usually, this doesn’t result in an explosion, but the amount of heat they release is so significant that it can set fire to anything flammable nearby.

Some people who have overcharged their LiPo batteries beyond what is advised by the manufacturers have achieved some pretty impressive explosions when they have damaged the battery, but in most cases, this doesn’t occur.

To avoid damaging your LiPO batteries, read the directions carefully. If you follow the directions that come with the LiPo batteries, the chance of problems occurring drops to nearly zero.

I have a few other tips for those who might be concerned about their LiPo batteries. All you need to do is keep them out of extreme heats, charge them using ONLY the charging equipment that comes with the battery, and be careful not to damage them or expose the interior of the battery to oxygen.

If your LiPo battery is swollen or begins to let off intense heat, it is most likely damaged beyond repair and needs to be cooled down and disposed of properly. Using a damaged battery can result in even more harm to your vehicle or the surrounding area. It is advised to bring a fire extinguisher with you when driving an RC car with a LiPo battery. You probably won’t need it, but it doesn’t hurt to have one, just in case.

The Motor

You can purchase a couple of different types of RC motors. Both have advantages and disadvantages, and it’s nice to know exactly what your car is capable of before you purchase it.

The brushed motor is a good motor for beginners as it is simple to repair and easy to control. Brushed motors are shaped like a cylinder. The outer casing has a negative charge on one side and a positive charge on the other side. It never moves and is known as the stator.

Inside of the stator is a cluster of wire coils (known as the armature) that rotates using magnetic charge. The coil is magnetized when the metallic pieces at the end of the coil (known as split rings) touch a point of contact that connects them to one part of the battery and gives them a specific magnetic charge.

However, as it rotates, the split ring meets with the other point of contact and the wire coil changes from positive to negative polarity. This pushes it away from one side of the stator and toward the other side.

Then, as it rotates, the point of contact changes again and is pulled toward the other side of the stator. This constant change from positive to negative and back again keeps the armature rotating at a fairly constant rate.

The split rings are known as brushes. When the brushed motor was first developed, they were actual copper brushes, but now these motors usually use spring-loaded carbon contacts. As the split rings and the points of contact continue to meet during activity, they gradually get worn down over time through a combination of mechanical friction and electrical corrosion.

This necessary friction also decreases the potential speed of the car and makes the motor require more electricity to rotate. In this way brushed motors use up their power source quicker. Rechargeable batteries die much more quickly with brushed motors than with brushless motors.

To their credit, brushed motors are cheaper and more common than brushless motors and, because they don’t travel at the same speeds, they also generally cause and experience less damage when they crash. If you so choose, you can purchase fixed motors, which aren’t adjustable. This means you can’t modify or fine-tune them, and if they break, you’ll probably have to replace the whole motor.

Brushless motors, on the other hand, are free from contact brushes that rub against each other. Instead of having a stator that has a positive and negative charge on each side, the stator of the brushless motor is ringed with small electromagnets.

These magnets are, true to their name, powered by electricity that allows every other magnet to either be positive or negative, then to switch to keep the rotor(the internal part that rotates around the electromagnets) moving.

The rotor is also ringed with magnets, but these magnets also have every other magnet possess the opposite charge. Unlike the stator’s magnets, however, the charge of these magnets doesn’t change.

As the electromagnets change polarity, the rotor is simultaneously pushed and pulled around. There are no points of contact, and so brushless cars very seldom need to have motor parts replaced. They are also significantly faster than those with brushed motors. These don’t get as hot, either, which affects their performance in a positive way.

Brushless motors often come with more complicated transmitters because they are capable of such impressive speeds, so the manufacturers assume that those who are purchasing them are more capable drivers.

They are also not as responsive as brushed motors, so they can be more challenging for a beginning hobbyist and much more expensive. In some circuits, brushless motors are still not allowed to race, so before you spend a lot of money buying a brushless RC car, make sure they are legal.

The Complete RC Vehicle

Now that you understand how all the individual parts work, it is fascinating to see the finished vehicle in motion. Knowing which parts cause what to happen within your vehicle can assist you in repairing and maintaining your RC car.

As you gain experience as both a driver and a mechanic, there are also a number of things that you can do to fine-tune and upgrade your vehicle. Personalizing and customizing RC cars is a huge part of the hobby and, if you decide to race professionally, is what creates a winning vehicle.

Related Questions

What are gas RC cars? Originally, all nitro cars were known as gas cars, but as cars were developed that used either nitro or gasoline, they began to differentiate the two different kinds of cars by calling cars that used gasoline ‘gas RC cars,’ and cars that used nitro fuel ‘nitro cars.’  Gas RC cars are larger, slower, and not very popular. Most RC enthusiasts recommend that you stick to either nitro or electric.

How have RC cars changed since they were first designed? The first RC cars were produced in 1966 by the Italian company El-GI (Elettronica Giocattoli). Proportional radio control made RC cars possible.

Previous to this year, radio control was much more primitive and didn’t allow for fine-tuned steering. It was suitable for aircrafts and boats, which just needed basic directions, but it wasn’t good enough for cars.

In the 1970s, gas and nitro cars were sold in Britain, and a few products were created in the United States. The early models were all nitro-powered (but, of course, back then they were known as gas) aluminum flat pan cars. The K&B Veco McCoy became the most popular engine during this time, with the cars’ bodies being made out of polycarbonate.

The cars were 1/12 scale compared to full-size cars. However, as interest grew, the cars were scaled up to 1/8 scale. In 1976, Tamiya, a Japanese-owned company, began to sell electric cars after the NiCad rechargeable battery was developed.

This was a huge development, because previous to this, batteries were heavy lead acid or expensive disposable. You can still use NiCad batteries, but they have several disadvantages that make them less popular than Ni-MH or LiPO batteries today.

As their popularity spread, Tamiya began to produce off-road RC vehicles as well, with realistic suspension. More and more different types and models were developed and produced as more consumers demanded RC cars.

This boom carried into the mid-1980s and is responsible for many of the different models of cars that exist today. Original Tamiya RC cars from the 70s and 80s can fetch impressive prices now, especially if they’re in mint condition. Some have been sold for as much as $3000 for their original, unbuilt form in pristine condition.

More companies began to compete with Tamiya and develop their own advancements. Adjustable ball differentials and shock absorbers were added into RC cars, which began to be made out of lighter and higher-quality materials. Four-wheel drive was added in 1986 by Schumacher Racing Products.

Traxxas (Click here to see if the VXL is good for bashing) and Kyosho also became prevalent and well-known brands (Click here to see why). As brushless motors began to replace brushed motors, and more powerful batteries like Ni-Mh and LiPo were developed, cars began to be more powerful and capable of speeds that the early RC car pioneers could never have dreamed of, themselves. Telemetry has even begun to be developed to store data from the vehicles. Some companies are now working on two-wheel car designs.