As someone new to the whole RC hobby, you might be brimming with all sorts of curiosities. I remember the feeling of extreme excitement and wonder of my days as a new RC car owner. So, just like me back then, you might also be curious to know, how do RC cars turn?
The control signal is sent by the transmitter to the receiver where it is filtered and processed. Depending on the signal, the receiver then instructs the servo to turn the wheels and the motors to throttle. In the case of skid steering, turning is achieved by varying the speed of the motors connected with the RC car’s wheels.
The RC car turning process is a bit complex and lots of components are involved with this process. That’s why, in this article, I will give you a brief explanation of how RC car steering works and how to adjust steering. I will also talk about the most common radio-controlled car steering problems and provide a troubleshooting guide so that you can fix them easily. So, without further ado, let’s begin!
Understanding How RC Car Steering Works
Radio-controlled cars are very complicated devices that are composed of basically four different parts. They are – transmitter, receiver, power source, and steering system. For RC cars to turn, each of these parts has its role to play. And their synchronized combined actions result in an RC car turning successfully in a certain direction.
Here, in this section, I will take a close look at each of the main components of an RC car. So, let’s jump right into it!
All RC vehicles come with a small handheld device that includes a radio transmitter and some type of control. Usually, RC car owners prefer wheel & trigger type radio controllers while others stick to the airplane-style “stick” radio controllers.
The radio transmitter on the controller sends signals over a frequency. And the receiver on the RC car receives this signal. The controller has a power source, typically a nine-volt battery, that provides the power required for controls and signal transmission. One of the key advantages of radio-controlled devices is that you can control them wirelessly.
Typically, RC vehicles operate at either 27 or 49 MHz The Federal Communications Commission (FCC) has allocated these two frequencies for basic consumer products such as walkie-talkies, garage door openers, RC vehicles, etc.
However, some advanced radio-controlled toys, especially sophisticated RC airplanes use either 72 or 75 MHz
Usually, manufacturers label the RC vehicles with the operating frequency range. Most of the time, you can get versions of the same radio-controlled car for both 27 and 49 MHz frequency range.
As a result, you can operate two of the same vehicles at the same time, for playing together or racing, without worrying about any interference between the two transmitters. Some RC car manufacturers even allocate a specific portion of the operating frequency band for each model.
Transmitters for radio-controlled cars range from single-function controllers up to full-function controllers with a wide range of functionalities.
For instance, in the case of single-function controllers, when you press the trigger, your RC car will go forward. On the other hand, upon releasing the trigger, the car will start to go backward. To stop the car, you will have to turn it off altogether.
In the case of full-function controllers, they have six controls. These are – Forward, Forward and right, forward and left, reverse, reverse and right, reverse and left. And unlike single-function controllers, until you don’t press any buttons or knobs in the full function controller, the car will remain in a stop position and await further commands.
Most radio controllers nowadays use a dual joystick system along with several levels of response for accurate control of the RC vehicle.
As you might’ve already guessed, the function of the receiver is to receive the signal transmitted by the transmitter. And to avoid any sort of interference with other radio-controlled systems, both the receiver and the transmitter have to be on the same frequency.
When you press a button or trigger of your RC car’s radio controller, it will send a signal. And the receiver will receive it. This will cause a specific action to occur in your radio-controlled vehicle such as your car will move forward or turn in a certain direction. This is just a simplified explanation of how RC receiver’s work.
But you might still have doubts about how these receivers identify specific signals emitted from the transmitter. Don’t worry, I’m going to explain this process down here:
1. When you press a button or a trigger in the radio controller, it will cause a pair of electrical contacts to touch. This will complete a circuit connected to a specific pin of an IC (Integrated Circuit).
2. As the circuit is completed, it will cause the transmitter to send a specific sequence of electrical pulses. Each set of pulses sequence consists of a short group of synchronization pulses, followed by the electrical pulse sequence that tells the receiver about the incoming information.
Usually, a full-function controller works through the pulse sequences given below:
- 16 pulses = Forward
- 28 pulses = Forward Left
- 34 Pulses = Forward Right
- 40 Pulses = Reverse
- 46 Pulses = Reverse Right
- 52 Pulses = Reverse Left
3. The transmitter on the handheld radio controller transmits bursts of radio waves that oscillate at the same operating frequency range used by your RC car’s receiver.
4. Your radio-controlled vehicle’s receiver will continuously monitor its assigned frequency for a signal. When it receives the signal burst from the transmitter, it will forward the signal to a signal filter. If the receiver’s antenna picks up any signal other than its assigned frequency, this filter will block them out.
5. Upon filtering the signal, the receiver will send the pulse sequences to the integrated circuit (IC) which will decode the signal and take appropriate actions such as starting the motor or moving the servo in a certain position.
For instance, If the received pulses sequence is 16 pulses, the integrated circuit (IC) will send a positive current to the motors. And this will result in your radio-controlled car moving forward.
On the other hand, if the pulse sequence is 40 pulses, the integrated circuit will reverse the direction of the current flow in the motor. This will result in your RC car moving in the opposite direction.
There are several ways to power a radio-controlled car. Lithium-polymer, nickel-metal hydride, or nickel-cadmium batteries and powerful but small electrical motors are what powers RC cars. These can be either brushless or brushed electric motors.
In terms of efficiency and power, brushless motors are far superior to brushed ones. But they tend to be very expensive also.
The next category of RC cars is known as “Nitro” cars. This type of vehicle is powered by a small internal combustion engine or glow plug engine. As for fuel, they typically use a special combination of methanol, nitromethane, and oil (usually a mixture of synthetic oil and castor oil.)
However, you can find gasoline engines on some large-scale models. And these vehicles use a mixture of gasoline and oil as their fuel source. In terms of ease of use and maintainability, electrical radio-controlled cars are far easier to work with as opposed to nitro cars. But they can also be as complex as fuel-driven ones at the higher skill and budget level.
In terms of upgradability, electrical RC cars are far more versatile and easier to upgrade compared to internal combustion engine-powered ones.
Usually, you can find two types of steering systems in RC cars. They are:
1. Separate Steer and Throttle
The goal of the steering system is to make sure that your RC car’s wheels are pointing in the desired direction. In most radio-controlled cars, the steer and throttle work separately. This type of steering system consists of a series of pivots, mechanical linkage, gears, and servo.
Most of the time, this type of steering system is located at the front of the vehicle and controls the direction of the front wheels only. You can find it in both electrical and nitro RC cars. In the case of nitro vehicles, the servo acts as throttle and brake linkage.
Upon receiving the steering information from the transmitter, the servo deflects in accordance with the received information. As a result, the wheel turns and when you press throttle on the controller, the motors on the RC car will rotate the wheels and your car will turn in your desired direction.
2. Skid Steering
In this type of steering system, you will not find any servo to turn the wheels of the radio-controlled car. Rather, the steering and forward/reverse motion are achieved by varying the speed of the motors connected to the car’s wheels.
Usually, you will find this type of steering system in electric RC toy cars. In the case of skid steering, there is no steering mechanism attached to the wheels.
RC car steers but won’t move? See my article here
After receiving the pulse sequence, the signal is sent to the integrated circuit of the vehicle. There the signal is processed and depending on that, the left and right wheel motors turn at different speeds. This results in the wheels dragging or skidding across the ground which ultimately turns the car in your desired direction.
Most Common RC Car Steering Issues
If you are an RC car owner, you will face a lot of problems regarding steering the car. In this section, I will talk about the most common RC car steering issues that you might face and what could potentially cause them. Let’s take a look at them, shall we?
- Throttle Works Perfectly but No Steering
This is the most common type of problem that every radio-controlled car owner has faced at least once in their lifetime. Your car may turn on properly, all the indicator lights may work as they are supposed to, but no matter what, your car won’t just turn.
The potential cause of this problem can be many things. For starters, damaged or displaced servo gears, or loose servo connections, or worn-out wires can cause this problem. This problem can also occur if the links in the steering system are not connected properly or are not of the correct length.
- Tires Automatically Turn Hard Right/Left
Sometimes your radio-controlled car may be able to turn right or left, but it will lean on one side more than the other. Or, you might notice that it can turn effortlessly but struggles to move in a straight line.
The likely cause of this problem might be the servo horn or where the servo trim is centered. Check for any irregularities in the servo horn and all the links in the steering system.
- Steering Sticks Right or Left
This is one of the most annoying problems you might face while driving an RC car. As soon as you turn your car on, you will notice that its tires will immediately turn to hard right or left. Sometimes, it might take a few minutes for the problem to appear after turning the vehicle on.
The culprit behind this problem is most likely the servo horn. Find out where the servo trim is set. Also, make sure the “End-Point Adjustment (EPA)” is set properly. If these don’t solve the issue, check the gears of your servo. If you find that they are stripped, replace the servo. Also, check if any links are loose or not.
How to Fix RC Car Steering Problems?
As you’ve already noticed, several things can cause RC car steering problems. And to accurately identify what’s causing the problem, you will need to know how to troubleshoot your radio-controlled car.
Solving most of the steering problems is much easier than it seems at a first glance. Down here, I’ve provided a detailed troubleshooting guide. In case you face any steering-related issues with your RC car, use the following guide to fix the problem.
1. Check Your Servo and Servo Horn
If you notice any problem with the steering, the first palace you should look for is the servo. Secure the servo horn properly on your RC car’s chassis. You will need to set the servo horn at a specific offset in some models. Check your car’s instruction manual. Any deviation from the manufacturer’s specification will result in steering problems.
Another thing to mention here, make sure you are using the right strength and size servo for your RC car. If you think there is something wrong with the servo itself, do a diagnosis to find out if it is faulty or not.
Burnt servo or damaged gears is the first thing you should look for if you think the servo is defective. Sometimes, a malfunction in the battery power connection to the receiver can cause the servo to stop working altogether. Plug a second servo to confirm if the receiver battery is delivering power to the servo or not.
It is very easy to overload the receiver battery if you connect a high-power servo with it. As a result, the servo will stop working. But that doesn’t mean it is defective. You may have bought a brand-new servo and it stopped working on its first run. This indicates there is a lack of voltage in the ESC’s internal BEC.
2. Find Out If All the Links Are the Correct Length Or Not
In almost every RC car that has a separate steering and throttle system, there are sets of links that establish a connection between the servo and the steering rack, and the steering rack to the front wheels. And in case the links are not of the right size or installed incorrectly, no matter how properly your servo and radio communicate, you will face steering issues.
After making sure the servo is functioning properly, investigate the links. Ensure that nothing is out of place between the servo, the steering rack, and the wheels. If everything is working correctly, they should respond instantly and smoothly.
3. Check the ESC and The Motor
If your electric RC car stops throttling altogether, you should assume that either the motor or the ESC (Electronic Speed Control) is faulty. Replace the motor with a spare one and run some basic loads for performing a bench test. If this solves the problem, that means you had a faulty motor.
You can do the same for your ESC by replacing it with a second one and running the same test to find out if the problem persists or not.
4. Has the Radio System Gone Bad? Check The Wiring
Sometimes you will find your RC car completely unresponsive. It will turn on, but will not move at all. If that’s the case, the first place you investigate is the radio system wiring.
Carefully investigate if all the wires that run to the receiver or the ESC system are ok or not. Your servo, ESC, and receiver get their electrical power through these wires. And if no power means they will stop working and which ultimately results in an unresponsive radio-controlled car.
5. Make Sure Your Receiver Is Working
Next up is the receiver unit. It is one of the most important parts of your RC vehicle. Even if one of the channels of the receiver goes bad, it can severely affect your radio-controlled car’s performance. You might not be able to throttle or steer properly or some other parts of the car might not work at all.
If you think something is wrong with the receiver, get a second receiver. If possible, get another radio system to test if the receiver is working properly or not. Plug your steering and throttle into another car’s receiver unit and perform a bench test.
6. Check the On/Off Switch
This one might seem a bit silly, but the number of times RC car owners face this problem might surprise you. Always check the on/off switches, either before starting the troubleshooting process or at the end. But never skip this step.
Double-check if your radio controller and the car are switched on or not. Also, make sure the receiver antenna is extended and you are using fully charged batteries. Sometimes, missing these simple steps can cause you a lot of problems.
You can test whether your RC car’s switch has gone bad or not by hot wiring the car. If the car starts, that means the switch is faulty. If not, then the problem lies in another component.
Adjusting Steering on An RC Car
Even the most experienced RC car owners fail to realize that their steering wheel needs frequent calibrating. This ensures your turns are precise which can be essential in case you are racing your car.
Adjusting steering on an RC car requires you to perform lots of checks and calibration. In this section, I will provide you with a step-by-step guide on how you can do that. Just take a look at them!
Step 1: To start with steering adjustment, first, you will need to check if the RC car is steering in the correct direction. To do that, push right on your radio controller and see if the wheels turn to the right or not. Next, push left on the controller and see if the wheel turns to the left.
If both the times the wheels were turning exactly as it was supposed to, that means the car is steering in the right direction.
Step 2: Next up is the steering trim. If your controller comes with a digital display, make sure the trims displayed on the screen are centered properly. Also, ensure that the sub-trims are set to zero.
For analog controllers without any display, look at its backside where you should find some knobs with arrows on them. Make sure to align the arrows with the marks on your controller.
Step 3: After trim comes servo horns. Make sure the horn is perpendicular to the servo. Go through your RC car’s manual for all the necessary instructions regarding the servo horn offset.
If the horn is not perpendicular to the servo, pull it off and move it over one tooth. However, this is not an accurate way to do this. You can use your radio controller’s sub-trim setting to accurately set the horn. If your controller doesn’t have this functionality, use the regular trim to set it.
Step 4: In this step, you will have to make sure the servo arm and the servo horn are in parallel to each other. You will need to position the links properly to make them parallel. Next, adjust the steering tie rods to your desired setting.
Step 5: Now, you will need to set your dual rates. This lets you adjust the “throw” of the input. This means the entire level of the steering/throttle inputs from the controller is a bit scaled-down.
Such adjustments are very useful when you are driving your RC car at a very high speed. In that case, extreme steering angles can lead to accidents. Beginners who are trying out powerful radio-controlled cars can use this to their advantage by turning things a bit down.
Step 6: Finally, it is time for you to set the End Point Adjustment (EPA). To do that, first, set your car on the ground at drive height. To make sure your car is at its true drive height, press its shock mount a couple of times before setting the EPA.
Next, turn everything on. Make sure the wheels of your RC car fully lock to the right and the left when setting endpoints. When you crank the steering, you will hear a buzzing sound coming out of your RC car. This indicates the servo is at its maximum limit and you will need to adjust back on your EPA (End Point Adjustment).
Now set the endpoint. By setting the EPA, you will have 100% throw both ways on your RC car’s steering.
Note: To get the maximum “throw” to your steering, set the dual rate to 100%. If you feel like this is not enough, consider replacing the servo horn with a larger one to get a better range of steering. Also, if your servo doesn’t provide sufficient torque for steering, upgrade to a servo that can generate higher torque.
For smoother steering action, you might want to adjust the servo saver nut. Make sure it is reasonably right. This will prevent the servo saver from having a softer feel and will give you your desired steering output.
I hope by now you have a decent idea of, how do RC cars turn? Turning an RC car is achieved through the synchronized actions of the different components that it is made of. And having a basic idea of how the turning mechanism works is the first step to becoming a full-fledged RC enthusiast.
When you drive your RC car, you might face some steering-related issues. In that case, just follow the troubleshooting guide I’ve provided in this article. This will make it easy for you to identify the source of the problem and fix it later. Also, always remember to calibrate your steering from time to time.