An ESC unit is a crucial component in any RC vehicle, and many situations can cause the ESC to operate improperly or fail altogether. If you fly an RC plane, how can you tell if the problems you are having are ESC related, and what can you do about them?
There are many situations where the ESC in your RC plane may not initialize or appear not to be functioning correctly. In many of these situations, it is usually a calibration issue, an incompatibility between ESC and motor, or a wiring or overheating problem.
Some RC plane issues can be difficult to pinpoint and find the root cause to rectify. Problems with the ESC can be difficult to diagnose since some controls may indicate the ESC is working while others tell a different story. We will help you to figure out if your problems are caused by the ESC and what you can do to fix the problems.
Diagnosing RC Plane ESC Problems
Part of diagnosing ESC problems in an RC plane is understanding how the ESC works and what its function is in the aircraft.
There are several differences between ESCs made for RC cars and ESCs made for RC planes, boats, and RC helicopters.
The ESC issues in a radio-controlled plane can range from simple to complex. We will show you how to distinguish between these problems, what to check and how to know when it is time for a new ESC unit!
What Does An ESC Do In An RC Plane?
The acronym ESC stands for Electronic Speed Controller, and the circuitry in an ESC is designed to control and manage the speed of the electric motor in the RC plane.
The primary motor is the electric motor that drives the RC plane’s propeller to provide the aircraft’s forward motion. The ESC interprets signals from the radio receiver to increase or decrease the motor speed based on the input from you, the operator of the transmitter.
While this may sound fairly straightforward, some complicated electronics happen in the circuitry that enables this communication between the radio receiver, the ESC, and the RC plane’s motor.
In the early days of ESCs, the circuitry was separate from the radio receiver in the RC plane and often had its own power supply separate from the radio receiver.
In modern RC planes, the ESC is often integrated into the same circuit board as the radio receiver, and they share the same power supply. This modification reduces the weight of batteries needed to power the electronics and gives some communication advantages between the two systems.
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We will examine some frequently experienced problems with RC plane ESCs and how to investigate these issues to determine the course of action to resolve them.
Common ESC Problems In RC Planes
Since the ESC is crucial to the proper functioning of the RC plane, it stands to reason that when things go wrong with the ESC, it is noticeable immediately.
Some problems that occur on the RC plane are simple configuration or compatibility issues, while others are indicators of more serious problems on the ESC unit.
Use The Right ESC For Your RC Plane Motor
There are essentially two main electric motor types used in the RC world; brushed and brushless motors.
The differences in the way the two motors work require a different ESC for each type of motor. The speed of brushed motors is adjusted by varying the voltage to the armature. The speed of a brushless motor is controlled by varying the speed of the pulses of current delivered to the motor.
Thus, a brushed motor is controlled by varying the voltage while a brushless motor by varying the current. Consequently, if you try to use an ESC designed for a brushed motor on a brushless motor and vice versa, it will not work.
Always ensure the ESC is designed for the type of motor you use in your RC plane. The most popular motors for use in RC aircraft are brushless motors due to their lighter weight and superior efficiency, power, and durability.
However, some RC plane models use brushed motors, so you need to make sure what type of motor you are dealing with and match it to the correct ESC.
The RC Plane Controls Work, But The Motor Does Not Spin Up
A frequent problem experienced in RC planes where operators have installed new components is that the controls all seem to work on the aircraft, but the motor refuses to spin up.
If you have power to the ESC and the ESC beeps appropriately to show it has initialized when you turn the unit on, you may think that all is well in the plane. If the flaps, rudder, and other controls seem to function when the RC controller is manipulated, you may be even more frustrated about why the motor does not spin up.
If these symptoms sound familiar, go through the following checks to pinpoint the problem.
- Check for Voltage compatibility. Ensure that the output voltage specified for the ESC corresponds to the motor’s working voltage. If the motor is brushless, check that the amp rating on the motor is compatible with the current output of the ESC.
- Check motor compatibility. Some motor types have built-in electronics that make them unsuitable for use with certain ESC units. Each ESC will have a list of compatible motors issued by the ESC manufacturer
- Makes sure all connectors are properly seated. RC planes experience vibration and jostling when operated or being transported. Make sure all the wires connecting the motor to the ESC are properly connected.
- Pair the motor to the ESC. Each ESC will have a configuration or pairing process that allows it the test connections and establish communications with the motor and radio receiver. The basic steps to do this initialization will be detailed below.
Failure to initialize an ESC is a common cause for all other controls to work but not the motor. The ESC must be initialized with your radio controller and the motor to properly interpret the signals.
The ESC needs to know what signal indicates full throttle, which indicates the lowest throttle setting, and which indicates engine idling speed.
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ESC In RC Plane Overheats
The ESC uses electronic components called FETs or Field Effect Transistors to control voltage or amps delivered to the motor.
The functioning of the FETs generate a significant amount of heat, requiring that the components are kept cool to avoid overheating.
A common problem in the limited internal space of an RC plane is to jam the ESC into some unventilated corner of the aircraft to get it out of the way.
This practice will cause the ESC to overheat quickly and shorten your flight times. The ESC must be positioned in the RC plane where it can have a constant airflow via an air intake to provide the cooling effect it needs.
Remember that an effective air-cooling intake for the ESC must have an outlet to generate the flow, and the outlet must be larger than the inlet port.
Poor Soldering Or Connecting Of ESC Wires
If you are serious about flying RC planes, you will inevitably be required to perform some wiring tasks to connect the various internal components in your aircraft.
Many RC operators are unaware of the importance of using the proper connectors for their wiring or the importance of quality soldering.
Using mismatched connectors on wires and attempting to jimmy them to fit is a recipe for gremlins creeping into the system and creating problems that are difficult to diagnose. These connectors can also become dislodged during flight, causing the aircraft to crash.
Soldering is another skill you will need to master to connect wires and install connectors on wires. The importance here is to use a soldering iron with the correct power rating to prevent overheating wires and components while soldering.
The best size soldering iron for the type of soldering required in RC planes is a maximum 30W iron. This size will prevent overheating the components but have sufficient power to solder connectors and components to circuit boards.
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Poor Quality ESC Or Motor In The RC Plane
The combination of the ESC and the motor are the brains and brawn of your RC plane. Consequently, you should never compromise by using cheap replacements for these important components.
Cheap or poorly constructed ESC units have the potential to fail, and in some cases, they can send spikes of current or voltage to the motor and burn out the motor.
Many cheap ESC units will provide unreliable service and may have fluctuations in power or signals received from the transmitter, which will have disastrous effects during flight.
Similarly, cheap motors can perform erratically, not interpret the ESC signals correctly, and even send pulses of current back into the ESC, which can burn out the circuitry of the ESC unit.
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It would be a travesty to pair an expensive ESC with a cheap motor only to have the motor burn out the ESC unit!
Always choose quality, proven components from reputable suppliers when buying motors and ESC units for your RC plane.
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ESC Does Not Allow Full Throttle
Many ESCs have a secondary circuit called a BEC or battery elimination circuit. The function of the BEC is to allow the radio receiver, ESC, and motor to be powered by the same battery bank.
When the RC plane uses this arrangement, there is usually a low voltage cutoff circuit that monitors the battery voltage and limits or cuts power to certain components when this limit is reached.
When this circuit kicks in, it typically reduces the power to the motor or cuts it off altogether to allow power to be sent to the directional controls so the operator can glide the RC plane in for a dead-stick landing and save the aircraft.
If your battery pack is underpowered or there are insufficient cells functioning in the battery pack, the circuit will detect a drop in battery voltage when you try to push to full throttle. The circuit will prevent full throttle to avoid draining the battery to critical levels, killing all the controls, and crashing the plane.
While this problem is not directly an ESC issue, the circuitry on the ESC is not allowing full-throttle because of a potentially hazardous situation elsewhere in the system. It serves as an indicator of a problem that must be investigated.
There are several battery-related issues you can check to resolve this problem.
- The battery is not fully charged. If the RC plane’s battery is not fully charged, the voltage may be too low to support all the functions in the aircraft. Check the battery is fully charged and that your battery charger is functioning correctly.
- The battery may be defective. RC batteries are made up of cells, and each cell must charge equally to fully charge the battery. If some cells are defective, the battery will not charge fully and should be replaced.
- The battery is too small. If you have added new or larger components to the RC plane, your battery may have a too low voltage rating to deliver enough power to the components without the BEC kicking in and limiting power to the motor.
Throttle Is Not On Zero On RC Controller
When you turn on the ESC, you may find that the ESC will not arm or initialize and give you the customary beeps to let you know all is ok.
A common problem that results in this error is when your throttle control on your RC controller is not at the zero position when you turn on the ESC.
This precaution is a safety feature on many ESC models to prevent accidental starting of the propeller, which has the potential to cause injury.
This feature is also important for the ESC to establish where the zero throttle position is on start-up as part of its initialization process.
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Ensure your throttle on your controller is zeroed before turning on the ESC; otherwise, it will not initialize.
Troubleshooting ESC problems on an RC plane can be one of the more challenging issues of flying these aircraft. Often, the cause of the problem is not immediately apparent and requires some investigative work to figure out the issue.
Fortunately, most issues are relatively easily remedied once the cause has been established, unless it has resulted in a burned-out, fried ESC!