Plane motors are getting the right one.

So, how does one pick the ideal motor for an RC aircraft? The optimal engine for every RC plane is a problem that cannot be solved in a one-size-fits-all manner. Instead, the sort of RC plane you buy will determine the optimal motor for your aircraft.

Since there isn't a lot of material available on the Internet nowadays that covers how to pick the best RC motor for one's RC plane, we've prepared this guide to help you out. Below, we've provided a condensed summary of what to anticipate from the various motor parts and motors currently on the market.

RC Plane Motors as Power Systems

These days, choosing a high-quality power system for your RC plane's motor is more difficult than it may seem. Determining the ideal RC plane motor can require some educated guesswork.

Making an educated guess is more comfortable than calculating every piece of information required to determine the ideal power supply for an RC plane model.

You must acquire some fresh information to make an educated guess about your RC plane's motor. Our guide will concentrate on it below.

To help you estimate the best motor for your RC plane, we'll provide you with the experience you need.

No one-size-fits-all solution exists to this problem because different RC planes work better with other motors. Instead, you'll need to learn about the specifications you'll need for the motor of your RC plane and utilize the information we've provided below to help you decide what kind of RC plane motor you should buy.

Accounting for Wing Load and Stall Speed

The wing load and the stall speed of your RC plane must be considered when making an informed choice about which RC plane motor is best for it. First, a wing load is calculated by dividing the aircraft's laden weight by the area of the wing.

Understanding your RC plane's wing load capacity will give you a basic idea of its lift-to-mass ratio, influencing its ability to ascend quickly, maneuver, and carry loads.

Some RC plane fans believe that the ideal method to build an RC plane is to use motor components that are as light as possible. Although this might seem like a strange strategy at first, these RC plane enthusiasts have a well-founded motive for wanting a lighter aircraft.

Flying a fighter aircraft will be more pleasant since it has a reduced wing load. A lighter plane minimizes the possibility of stalling.

An RC plane experiences a gravitational pull during a turn, which causes its weight to increase. This procedure is comparable to a string's weight at its end.

When you twist it around like a lasso, the thread will become heavier on one end. In an RC plane, the stall speed increases with increasing wing loading during a turn.

The rate at which other factors can also influence an RC plane stalls. The aerofoil form and the aspect ratio of the aircraft can influence an RC plane's rate of stall speed. You will need to increase the size of your RC plane's wings if you have a hefty model and need to reduce the weight of its wings. Therefore, you can achieve faster stall speeds with models with strong side loading capacities.

Wing loading is often calculated using either oz/ft² or gr/dm², where one dm² equals 15.50003 inch². Click here for assistance in determining the wing load on your remote-controlled aircraft.

Accounting for Volts, Amps, and Watts

The next factor to consider when selecting the best RC plane motor is volts, amps, and watts once you have considered your plane's stall speed rate. It's a good idea to use the hydraulic analogy to understand better how these things function and impact the engine of your RC plane. Because voltage is similar to water pressure, the hydraulic analogy compares electric circuits to water-filled pipelines. Determining the electrons' speed through the channel is aided by voltage.

Using the same scenario, you must understand how current functions. Current is a measurement of the volume of water that flows past a specific place and is typically expressed in amperes. The movement rate determines the voltage, and the total output of the voltage is expressed in watts. Volts x amperes = watts is commonly used to calculate all these components.

Selecting a Motor for Your RC Plane

Before picking a motor, it is vital to know the differences between each type on the market. The video below provides some concise explanations to help you better comprehend the various motors.

Several factors must be taken into account when selecting a motor for your remote-controlled aircraft. These include the voltage, gearboxes, electronic speed control, cut-off voltage, power selection, weight, power, and dimensions. These topics will be discussed in further detail below.

RC Plane Weight Power and Dimensions

Before choosing a motor for your remote-controlled aircraft, you must consider its weight and size. You don't want to add more weight to ensure your RC plane has the proper center of gravity, for instance. Rather than buying a smaller, less powerful engine, it is preferable to have a larger, heavier, and better-motored RC machine instead.

We recognize that you might not always have a choice in the matter, depending on your financial situation. The relationship between your motor's weight and your RC plane's center of gravity should not be overlooked, though. Your RC plane's engine specifications are crucial, and you should never buy a motor that you know won't fit your model in the first place.

Therefore, you must look for an engine that provides the performance your present RC model plane requires when looking for the best RC motor. For instance, you will want a motor with a thrust more significant than one-to-one if you have a 3D model. On the other hand, you won't need as much propulsion for your model if it's a scale 1918 biplane.

Remember that the watts per pound rule will not be as accurate as it typically is if you maintain your motor above its maximum efficiency. This is because a more significant proportion of Watts will generate heat rather than electricity. Here are some suggestions for your RC plane regarding Watts per pound.

70-90 watts per pound: Aerobatic models for training and slow motion.
90-110 watts per pound: Sport variants that move quickly and aerobatically.
110-130 watts per pound: Faster and more sophisticated user aerobatic models
130-150 watts per pound: Ducted fan models and light-loaded 3D models.
150-200+ watts per pound: Unlimited 3D model planes.

After briefly discussing the weight and power requirements for your RC plane's motor, we'll explore whether an in-runner or an outrunner engine would be more suitable.

RC Plane Motors: In-Runner and Outrunner

It's time to talk about the kind of RC plane motor that would work best for your model. You will discover that both in-runner and outrunner engines have advantages and disadvantages. The motor you choose will depend on the kind of RC model plane you are using and what works best for the RC plane you already own.

In-Runner RC Plane Motors

We'll start by going over the fundamentals of in-runner motors. Typically, in-runner engines are constructed with magnets fixed directly to the shaft. Copper windings then surround the shaft. Due to the magnets' proximity to the shaft, the shaft coils up and rotates quickly. Thus, while these motors produce high RPMs, their torque is limited. You can use a gearbox to turn the high RPMs into torque if you like.

In-runners are typically regarded as the more potent and effective option when compared to outrunners. However, if in-runners are being utilized to move giant propellers, they must have a gearbox. Compared to outrunners, in-runners also produce more revs per volt. The most common option for RC plane models that require a small prop to dash, complete with ducted fans and pylon racers, is typically an in-runner with a gearbox.

But once you install a gearbox in your in-runner, you'll have additional benefits and drawbacks. It is important to remember that gearboxes are not inexpensive and typically need a significant investment. Additionally, gearboxes tend to be louder and require more maintenance. However, the most essential power and efficiency will come from a gearbox with a geared in-running capable of spinning a giant prop.

See Also: What Is the Weight of a Drone?

We will now discuss the operation of outrunner motors after you have a better understanding of in-runner motors.

Outrunner RC Plane Motors

Outrunner RC plane motors are typically built using copper windings inside the engine. The shaft area of an outrunner will be joined with a "bell," which may also be a casing that contains the magnets. The motor can rotate around the copper windings thanks to the magnets and the housing. An outrunner engine functions similarly to a flywheel because of the additional weight from the bell on top of it and the magnets that are dispersed farther from the shaft.

An outrunner motor will provide more torque and a lower RPM than in-runners. Thus, an outrunner engine can spin a considerable prop without a transmission. Because outrunners don't require a gearbox, you'll end up with a quieter motor that requires less maintenance and costs less overall because you won't have to purchase the pricey gearbox.

A gearbox-free outrunner offers several advantages that some people find difficult to resist. Therefore, for some RC plane enthusiasts, the silent operation and lower cost will offset the increased power and efficiency that an in-runner would provide.

What is KV?

You must also comprehend what KV signifies when choosing the best motor for your RC aircraft. KV describes how many revolutions per minute (RPMs) an electric motor can run per volt without a load. What distinguishes having a low KV from having a high KV, then? Consider these distinctions comparable to the difference between a conventional Harley Davidson four-stroke motorcycle engine and a high-performance racing two-stroke motorcycle engine.

A two-stroke motorbike can achieve this at 11,000 RPMs, but the two-stroke and four-stroke motors will consume the same horsepower. However, the four-stroke can accomplish this at 3,000 RPM. How high and low KV electric motors operate is similar to this comparison.

A high KV in-runner motor with a tiny diameter propeller would function well in a high-speed model, such as a racer, provided that both motors use the same voltage. On the other hand, a low KV motor with a larger propeller might function better for power, such as raising a sailplane to its altitude.

By counting the number of winds or rotations the propeller makes, you may calculate a motor's KV. The number of times the copper wire circles the stator pole is indicated by the number of winds or turns. The KV decreases with increasing winds. The KV increases when the winds decrease.

Lower KV or Higher KV?

What are some of the distinctions between higher and lower KV, then? Although we touched on this briefly before, we'd want to go into greater detail about it below. A motor with a high KV will spin more quickly than a motor with a lower KV running at the same voltage. Therefore, you should consider utilizing a high KV motor if you use a battery with a lower voltage. This idea is particularly relevant if you enjoy racing and competition, which a higher KV motor could benefit from.

If you don't have to worry about the constraints of a particular voltage, you could utilize a lower KV motor at a higher RPM by starting a higher voltage instead. You have a great example of a low KV motor that performs well if you often fly large outrunners with a KV of 200 to 300. When considering a new engine purchase, you should also carefully consider the voltage restriction.

Choosing an In-Runner and a Gearbox

If you decide to use an in-runner motor, you must understand how to choose an engine and an in-runner. Even if the procedure can be tricky, you won't have any problems if you take the time to learn how to make wise purchases. Choosing an outrunner and a gearbox is comparable to choosing an inrunner, except with an outrunner, the gearbox is not a concern.

If you need to buy an in-runner motor, there are typically two options available. Feigao will be our example. All of Feigao's motors are listed on their website, Feigao.com, along with a complete set of engine numbers. As you can see, Feigao offers a variety of recommendations for configuring the motors. "380s" are Feigao's lower-diameter motors, while "540s" are their larger ones.

Three sizes are available for the Feigao 380 and 540: small, large, and extra-large. With the 380 translating into the B40 format and the 540 translating into the B50 size, most of the Feigos function similarly to Hacker in-runner motors. Therefore, if you wish to replicate a successful setup and conduct some research online, you can locate one. Additionally, you will find that the ratios for the Hacker and Feigao gearboxes are comparable, with the scale 540 having a ratio of 6:7:1 and the 380 sizes having a 4:1:1 ratio.

But what does the 6:7:1 ratio mean? To calculate that, you will need to know the prop shaft's KV with a gearbox. To determine that, you must divide the motor's KV by the gearbox's ratio. Try the Peak Efficiency website if you need assistance understanding all of this. You can experiment on that website to determine how your possible motor setup will operate with your RC plane. This website will offer you a sense of what might occur when experimenting with various possibilities.

RC Plane Motors and Electronic Speed Controls

After providing you with additional history on in-runner and outrunner motors, we will now discuss electronic speed controls or ESCs. Brushless and brushed motors are the two types of ESCs available in RC model airplanes. You should be aware that a brushed ESC cannot be used with a brushless motor, and the opposite is also true.

As a result, consider the many attributes you will require for the motor of your RC plane, such as a good brake or a gentle start. Consider adding a brake and a folding prop if your RC plane has a gentle start. If your RC plane has a gearbox and a switch to turn it on and off with the throttle, it's also a good idea to have a brake. RC sailplanes frequently have the traits we just discussed.

Match Your ESC to Your Motor

When choosing your ESC, you need to make sure that it is compatible with the motor you intend to use. If you can utilize an ESC with a higher amperage than you anticipate using your motor, you will have some protection against overtaxing your ESC and causing damage to your RC plane. An ESC will usually display a burst rating indicating how long you can use it at its maximum amperage.

You risk damaging your RC plane if you go over that limit. Most experienced RC plane enthusiasts like to have an ESC with 10–20% more amperage than they ever intended to use. You will need to purchase a meter to measure the amps and volts your power system can produce. This will assist you in making sure that your motor, battery, or ESC aren't being overstressed.

We'll explain what a BEC is in the world of RC planes to assist you in grasping this idea. The abbreviation for "battery eliminating circuit" is BEC. Therefore, a BEC is a tool to supply electricity to your RC plane's servos. A BEC that can only function appropriately over a specific voltage and number of servos is frequently found in ESCs. The number of servos you can employ will decrease as the voltage increases.

However, if you utilize too many servos on your BEC, your ESC will eventually overheat and fail. If your BEC malfunctions while your aircraft is in flight, it might be disastrous. So, an excellent method to be sure you have what your plane can take is to get an external BEC for your flight battery pack.

RC Plane Propeller Selection

Remember that your power system is subject to load from the propeller. Therefore, you risk harming your batteries and your engine and ESC if you buy the incorrect propeller. Keep in mind that props function similarly to a car's gearbox. You may slow down the motor by using props to create a first gear that runs at a high RPM. You will have much power but not much speed at that rate.

A propeller that functions more like a car's top gear is what you'll want if you want to move quickly rather than with a lot of power. This implies that your plane can maintain its speed for a while after you increase it. If this is your preference, you should get a prop with a total pitch of four and a diameter of ten inches.