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RC Car Motor Sizes: Motors In Motion

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RC car motor sizes are an important consideration when building or modifying an RC car. The size of the motor will determine the power output and speed of the car, as well as the type of battery and ESC required. There are a variety of motor sizes available, each suited to different types of cars and driving styles.

When choosing a motor size, it is important to consider the scale of the car. Different motor sizes are appropriate for different scales, with larger motors required for larger cars. It is also important to consider the type of driving you will be doing, as this will determine the power output required. 

No matter if you’re looking to upgrade your current motor or hunting for your next purchase, this lengthy article will give you better insight into your RC cars engine.

Understanding RC Car Motor Sizes

RC car motor sizes are an essential factor to consider when choosing the right motor for your vehicle. You have to determine if you’re looking for speed, performance, handling or some sort of blend of all three.

Motor Size and Performance

The most common motor sizes for RC cars are 370, 540, 550, and 1/8-scale. The size of the motor affects its performance, with larger motors providing more power and speed. Motor size is generally determined by its physical dimensions and power rating.

However, larger motors also consume more power and generate more heat, which can damage the motor and other components.

The motors power rating is measured in Kv, which stands for revolutions per volt. A higher Kv rating means the motor will spin faster, but it will also draw more current and generate more heat. The ideal Kv rating depends on the intended use of the motor and the voltage of the battery.

When selecting a motor for your RC car, remember to consider the weight of the vehicle, the terrain you will be driving on, and your driving style. A motor that is too small will not provide enough power, while a motor that is too large will consume too much power and generate excessive heat.

Brushed Motors

Brushed motors are electric motors that convert electrical energy into mechanical energy to produce motion in RC cars. These types of motors are commonly found in toy-grade RC models but can still be used in hobby-grade models.

Brushed motors have been around for a long time and are relatively simple in design, consisting of a rotor, a stator, and brushes.

One of the advantages of brushed motors is their affordability compared to their brushless counterparts. They are also easier to control and have a smoother power delivery. However, they are less efficient than brushless motors and require more maintenance due to the brushes wearing down over time.

Maintenance

To keep your brushed motor running efficiently, regular maintenance is required. One of the most important things to do is to clean the motor after every use. This will help prevent dirt and debris from building up and causing damage to the motor. You can use a soft-bristled brush to gently remove any debris from the motor.

Another important aspect of maintenance is to replace the brushes when they wear down. You can tell when the brushes need to be replaced when the motor starts to lose power or makes a grinding noise. You can purchase replacement brushes from your local hobby shop or online.

Efficiency

Brushed motors are less efficient than brushless motors. They have lower power output and are less responsive to throttle inputs. However, they are still a popular choice for beginners and those on a budget.

When choosing a brushed motor for your RC car, it is important to consider the size of the motor and the voltage it can handle. Most brushed motors are rated for a specific voltage range, and exceeding this range can cause damage to the motor.

Brushless Motors

Brushless motors are a popular choice among RC car enthusiasts due to their high power-to-weight ratio and efficiency.

Unlike brushed motors, brushless motors have no physical contact between the rotor and stator, resulting in less friction and wear. This makes them more durable and requires less maintenance.

Brushless motors use a standard numbering scheme to describe their physical size and Kv rating. For example, a 5055-3000Kv Brushless Outrunner Motor has a diameter of 50mm, a length of 55mm, and a Kv rating of 3000.

The Kv rating represents the number of revolutions per minute (RPM) that the motor will turn per volt applied, without a load.

Sensorless vs. Sensored Motors

Brushless motors can be either sensorless or sensored. Sensorless motors rely on the back electromotive force (EMF) generated by the motor to determine the position of the rotor. This makes them simpler and cheaper but can result in less precise control at low speeds.

Sensored motors, on the other hand, use hall effect sensors to detect the position of the rotor. This allows for more precise control at low speeds and smoother acceleration. However, sensored motors are typically more expensive and require more complex wiring.

Motor Size and Power

The size of a brushless motor is determined by its diameter and length, as described above. Different motor sizes are appropriate for different RC car scales. For example, a 1/10th scale RC car requires a motor with a 3650 size motor, while a 1/8th scale car requires a 4068 size motor.

The power of a brushless motor is determined by its Kv rating and the voltage of the battery it is connected to. Higher Kv ratings result in higher RPMs, while higher voltages result in higher torque. It is important to choose a motor with the appropriate Kv rating and voltage for your RC car to ensure optimal performance and avoid damaging the motor or battery.

Motor Size and Performance

Understanding Motor Size

Motor size is an important factor to consider when choosing a motor for your RC car. Motor size is typically measured in millimeters and is represented by the diameter and length of the motor. For example, a 3674 motor has a diameter of 36mm and a length of 74mm.

Different RC car scales require different motor sizes. For example, a 1/10th scale RC car requires a motor with a 3650 size motor, while a 1/8th scale car requires a 4068 size motor. It is important to choose the right motor size for your RC car to ensure optimal performance.

Factors Affecting Performance

Several factors affect the performance of an RC car motor. Here are some important factors to consider:

  • Kv Rating: Kv rating is a measure of how fast the motor spins. A higher Kv rating means a faster motor, but it also means less torque.
  • Number of Poles: The number of poles in a motor affects its torque and efficiency. Motors with more poles generally have more torque, but they also have lower efficiency.
  • Gear Ratio: The gear ratio determines how fast the wheels turn compared to the motor. A higher gear ratio means the wheels will turn faster, but it also means less torque.
  • Battery Voltage: The voltage of the battery affects the speed and power of the motor. Higher voltage batteries can provide more power to the motor, but they also require a motor that can handle the increased power.
  • Motor Timing: The timing of the motor affects its performance. Advancing the timing can increase the motor’s RPM, but it can also cause the motor to overheat and wear out faster.

Choosing the right motor size and considering these factors can help you achieve the best performance from your RC car. It is important to choose a motor that is appropriate for your RC car’s scale and intended use.

Understanding Motor Size

When it comes to selecting the right motor size for your RC car, there are a few important metrics to consider.

These include length, diameter, turns, and coils. Understanding these metrics will help you choose the right motor for your specific application.

Length and Diameter

  • The length of a motor is typically measured in millimeters (mm) and represents the distance between the front and back of the motor.
  • The diameter of a motor is also measured in mm and represents the width of the motor.

Typically, larger RC cars require larger motors with longer lengths and larger diameters. For example, a 1/8 scale RC car would require a larger motor than a 1/10 scale car. However, larger motors may not always be necessary, and can sometimes be too powerful for the application.

Turns and Coils

The number of turns and coils in a motor are also important factors to consider when selecting a motor for your RC car.

  • Turns: The number of turns refers to the number of times the wire is wrapped around the motor’s armature. The more turns a motor has, the slower it will spin, but it will also have more torque. The fewer turns a motor has, the faster it will spin, but it will have less torque.
  • Coils: Coils refer to the number of wire windings in each turn. The more coils a motor has, the more powerful it will be, but it will also be less efficient. The fewer coils a motor has, the less powerful it will be, but it will be more efficient.

When selecting a motor for your RC car, consider the number of turns and coils in relation to the specific application. For example, a motor with more turns and coils may be better suited for off-road racing, while a motor with fewer turns and coils may be better suited for on-road racing.

KV Rating and RPM

KV rating is one of the most important factors that affect the performance of an RC car motor. KV rating refers to the number of revolutions per minute (RPM) that the motor can generate per volt of power supplied to it.

The higher the KV rating, the faster the motor will spin. However, higher KV rating also means higher power consumption and more heat generation.

RPM refers to the speed at which the motor can spin. The higher the RPM, the faster the car will go. However, higher RPM also means higher power consumption and more heat generation.

Torque and Acceleration

  • Torque is the rotational force that the motor can generate. The higher the torque, the more power the motor can deliver to the wheels. Higher torque also means faster acceleration. However, higher torque also means higher power consumption and more heat generation.
  • Acceleration is another important factor that affects the performance of an RC car motor. Acceleration refers to the rate at which the car can increase its speed. Higher acceleration means faster speed and better performance.

Efficiency and Power Consumption

  • Efficiency is an important factor that affects the performance of an RC car motor. Efficiency refers to the amount of power that the motor can convert into useful work. Higher efficiency means better performance and longer run time. However, higher efficiency also means higher cost.
  • Power consumption is another important factor that affects the performance of an RC car motor. Power consumption refers to the amount of power that the motor consumes to generate a given amount of work. Higher power consumption means more heat generation and shorter run time.

Motor Brands and Reviews

When it comes to choosing a motor for your RC car, selecting the right brand can make all the difference. Here are some of the top motor brands for RC cars, along with reviews and budget options.

Top Motor Brands

  1. Castle Creations: This brand is known for producing high-quality, powerful motors that are perfect for racing and high-performance driving.
  2. Hobbywing: Hobbywing’s motors are popular among RC enthusiasts due to their excellent performance and affordable prices.
  3. Traxxas: Traxxas is a well-known brand in the RC world, and their motors are no exception. They offer a wide range of motors suitable for different types of RC cars.

Quick Reviews

When it comes to choosing a motor, it’s important to read reviews from other RC enthusiasts to get an idea of how the motor performs in real-world situations. Here are a few popular motors and their reviews:

  1. Castle Creations 1515: This motor is a popular choice for 1/8th scale RC cars. It’s known for its excellent performance and durability, and many users have reported that it’s easy to install and maintain.
  2. Hobbywing Xerun: This motor is a great budget option for those who want a high-performance motor without breaking the bank. It’s known for its excellent acceleration and smooth power delivery.
  3. Traxxas Velineon: This motor is a popular choice for Traxxas RC cars. It’s known for its excellent performance and reliability, and many users have reported that it’s easy to install and maintain.

Budget

If you’re on a tight budget, don’t worry – there are still plenty of great motor options available. Here are a few budget-friendly motors that still offer excellent performance:

  1. Turnigy TrackStar: This motor is a popular choice for those who want a high-performance motor at an affordable price. It’s known for its excellent acceleration and smooth power delivery.
  2. GoolRC Brushless Motor: This motor is a great option for those who want a budget-friendly motor that still offers good performance. It’s known for its durability and reliability.
  3. EMAX Brushless Motor: This motor is another great budget option. It’s known for its excellent performance and smooth power delivery, and many users have reported that it’s easy to install and maintain.

Final Thoughts

Choosing the right size motor for your RC car is essential to achieving optimal performance. It is important to consider the scale of your car, the required wattage, the KV rating, and the gear ratio when selecting a motor.

As we have seen, different motor sizes are appropriate for different RC car scales. For example, a 1/10th scale RC car requires a motor with a 3650 size motor, while a 1/8th scale car requires a 4068 size motor.

When calculating the required motor size, the formula to use is (Wattage Required / (KV Rating x Gear Ratio)) x 1.34. It is important to note that this formula is not an exact science, and the actual size of the motor required may vary based on individual factors such as the weight of the car and the terrain it will be used on.

Additionally, it is important to choose the right type of motor for your RC car. Brushless motors are generally more efficient and provide better performance than brushed motors, but they are also more expensive.

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