Quadcopters: A Beginner's Guide to Building and Flying

Building a quadcopter can be a fun and rewarding hobby, but it can also be intimidating for beginners. The first thing you need to know is that a quadcopter has four rotors, which are the spinning blades that lift the drone off the ground.

To build a quadcopter, you'll need to choose a frame, which is the base of the drone that holds all the other components together. The size of the frame will depend on the type of quadcopter you want to build, with smaller frames being more suitable for indoor use and larger frames being better for outdoor use.

A good quadcopter frame should be sturdy and able to support the weight of the motors, batteries, and other components. The frame should also have a clear path for the rotors to spin without any obstructions.

The motors are the heart of a quadcopter, providing the power needed to lift the drone off the ground and keep it flying. There are different types of motors available, including brushless and brushed motors, with brushless motors being more efficient and longer-lasting.

A drone is essentially a type of unmanned aerial vehicle (UAV).

It's characterized by its ability to fly without a human pilot on board, which is a pretty cool concept if you ask me.

Quadcopters, as we've discussed, are a type of drone with four rotors, each equipped with a motor and propeller.

Quadcopters are the most popular type of drone, and they come in various shapes and sizes. They're perfect for aerial photography, videography, and racing.

One of the most common types of quadcopters is the X Quadcopter, which is known for its versatility and stability. It's a great choice for beginners and experienced pilots alike.

Another popular type of quadcopter is the H Quadcopter, which features an H-shaped frame and is known for its stability. It's a great option for those who want a reliable and easy-to-fly drone.

If you're looking for a drone that excels in straight flight paths, the + Quadcopter is a great choice. It has aerodynamically efficient propeller positions, making it perfect for acrobatic flying.

For another approach, see: Quadcopters Drones

For those who want to take their drone to the next level, the V-tail or A-Tail Quadcopter is a great option. It offers enhanced yaw control through rear motors mounted at an angle, providing a more stable and controlled flight.

Here are some common types of quadcopters:

Overall, there are many types of quadcopters to choose from, each with its own unique features and benefits. Whether you're a beginner or an experienced pilot, there's a quadcopter out there for you.

Quadcopters generally have two rotors spinning clockwise and two counterclockwise, which provides flight control through independent variation of speed and lift.

Quadcopters don't usually have cyclic pitch control, unlike conventional helicopters, which can be a problem in vertical flight. This is because counter-rotation can eliminate torque-induced control issues.

The frame makes up around 90% of a quadcopter, so it's a crucial part of the design. A larger frame will be less agile and maneuverable, but it will be much more stable.

There are three main types of quadcopter frames: the "X" frame, the "+" frame, and the "H" frame, each with its own advantages and disadvantages. The "H" frame, for example, has more room available to mount electronics and batteries.

The classic "X" frame is a popular choice for commercial drones like the DJI Phantom, where the arms are at right angles to each other and the quadcopter looks nice and symmetrical.

One of the main differences between the "X" and "+" frames is the orientation when flying in the direction you call "forwards".

The "+" frame version is virtually identical to the "X" frame, with the only difference being the orientation when flying "forwards".

The arm sticking out when flying "forwards" in the "+" orientation can block the view of the camera, making it less commonly used.

The "Arm Lock MIR" in the drawings is the same thing as "Arm Lock".

Prop size is crucial for quadcopter performance. Cheaper props are less precisely manufactured and more prone to creating vibration, especially for larger props.

The quality of propellers can make a big difference in aerial photos and film. Spending money on top-quality propellers is worth it if you're flying a quadcopter for professional purposes.

When choosing propellers, keep in mind the three simple measurements: length, pitch, and bore. The length of a propeller is its diameter, usually given in inches.

A higher Kv rating in your motors means you'll need smaller props. Smaller props allow for greater speeds but reduced efficiency. A larger prop setup with low Kv motors is easier to fly steadily and uses less current.

Prop pitch is also very important. It's defined as the distance a prop would be pulled forward through a solid in a single full revolution. For example, a prop with a 7.0 inch pitch would move forward 7.0 inches in one revolution.

The bore measurement is the size of the hole in the center of the prop. This must be matched to the shaft of your chosen motors. Adapters are available to downsize a prop's bore, or you can use a direct mounting system like those produced by T-Motor.

Most quadcopters today use Self Locking props, which automatically lock themselves down and won't come loose when flying. This is because two motors spin clockwise and the other two spin counter-clockwise, using propeller threads that are opposite to motor spin direction.

The central flight controller is the brain of the quadcopter, taking information from various sensors and making computation calculations to control flight and stability.

It's a complex system that encompasses multiple features, including IMU, GPS, Gyroscope, and obstacle detection sensors. In fact, most flight controllers have dual IMUs for redundancy and other safety features, such as Return-To-Home.

A good example of a central flight controller is the DJI N3 Flight Controller, which has a wide range of features and can work with various motors.

Here are the key components of a drone propulsion system:

DJI and T-Motor are two companies that specialize in quadcopter motors, ESCs, and propellers. DJI's latest multirotor motors, such as the E5000, E2000, Snail, and E305, contain a quadcopter motor, props, electronic speed control circuits, and cooling system.

When choosing the material for your quadcopter propeller, you have a few options to consider.

The most common material used is plastic, which is a cost-effective and durable choice.

You can also opt for carbon fiber, a higher-end material that offers improved performance and durability.

Wood propellers are another option, often used in model aircraft due to their unique aesthetic and performance characteristics.

Electronic Speed Controllers are a crucial component of modern quadcopters, offering high power, high frequency, and high resolution 3-phase AC power to the motors. They are essential for varying the speed of the motors, which is necessary for controlling the quadcopter's movement and stability in the air.

Each quadcopter motor has a circuit called an Electronic Speed Control (ESC), which is responsible for controlling the motor's speed, direction, and braking. ESCs are small and compact, making them a vital part of the quadcopter's propulsion system.

Brushless motors, which are commonly used in high-quality drones, require an ESC to function. The ESC turns on and off the coils in a timed manner to keep the motor running, and its speed depends on the switching rate of the ESC. Brushless motors are faster and more efficient than brushed motors, which is why they are preferred in most drones.

T-Motor offers 17 types of ESC circuits, including the Alpha Series, Flame Series, Air Series, FPV Series, and T Series. The T-Motor Alpha 40A LV ESC, for example, is a low-noise, temperature, and interference ESC that is fast to respond.

If this caught your attention, see: How Do Delivery Drones Work

Here are some key features of T-Motor's ESC circuits:

In addition to these features, T-Motor's ESC circuits also use Field Oriented Control (FOC) Technology, which controls the motor output by adjusting the current flow and angle to control the magnetic field and torque of the motor. This technology allows for precise control over the motor's speed and direction.

When choosing an ESC, it's essential to consider the type of motor and propeller you're using, as well as the power requirements of your quadcopter. DJI, for example, offers a range of motors, ESCs, and propellers that are specifically designed for their drones, but can also be used by hobbyists and professionals alike.

Choosing the right battery for your quadcopter is crucial for a smooth and enjoyable flying experience. You want a battery that can provide the necessary power to your motors without being too heavy or requiring too much maintenance.

For a decent flight time, you'll need a battery with a capacity of at least 2200mAh. The higher the capacity, the longer you can fly, but also the longer it takes to charge.

Not all batteries are created equal, and the type of cells used can make a big difference. Lithium polymer (LiPo) batteries are the current standard, and they're made up of multiple cells that each provide 3.7 volts. You'll need a 3S or 4S battery, depending on your application.

The C-rating of a battery tells you how much current it can provide to the motors. A higher C-rating allows for a more agile and responsive aircraft. Look for a battery with a C-rating of at least 30 for optimal flight characteristics.

Here's a summary of the key factors to consider when choosing a battery:

Remember, a good battery is worth the investment, even if it means buying one rather than building your own.

Female bullet connectors get soldered onto three wires coming out from the ESC, while male bullet connectors are soldered onto two power wires from the ESC.

Female bullet connectors also get soldered onto the Power Distribution Board (PDB), where they're laid sideways and clamped onto metal contacts before being secured with melted solder.

The male XT-60 connector gets soldered to the PDB, with wires soldered to it and then connected to the PDB.

To ensure the female bullet connectors stay in place on the PDB, melt the solder all around them.

Mounting the components of your quadcopter is a crucial step in building a stable and efficient drone.

You'll need to use zipties to secure the motors, as they provide a strong and reliable mount. I've found that zipties work especially well with cardboard, which is a common material used in quadcopter builds.

Double-sided sticky tape is also a great option for mounting the ESCs, allowing for easy installation and adjustment.

The ESCs should be plugged into the PDB and the motor, with the signal wires fed to the top of the quadcopter. Don't worry too much about the wire orientation at this stage, as you can adjust it later if needed.

To reduce vibrations and improve flight stability, you can use 30dB earplugs as vibration dampeners for the flight controller. Glue them to the top plate for a secure fit.

The receiver should be mounted using velcro, which provides a secure and adjustable connection. Make sure to feed the antenna wires under the zipties on the arms, positioning them at a 90-degree angle to each other for optimal signal reception.

The transmitter and receiver are the heart of your quadcopter's communication system. They allow you to talk to the flight computer and control the drone's movements.

The transmitter and receiver come in various shapes and sizes, with the main differentiating factor being the number of channels they provide. Higher-end versions have more channels, which can be used for advanced features like mode switching and GPS return to home.

Binding is a process that takes literally 10 seconds, where you let the transmitter know it's talking to the specific receiver that came with your box. To bind, plug the bind cable into the "BAT" (battery) port on your receiver.

Aerial photography platforms require a gimbal to allow for cameras to be fitted, and a frame that keeps the propellers out of the camera's view is recommended. The TBS discovery frame is a good option, using a dead cat style frame to keep the arms apart.

Quadcopter flight principles are based on Newton's Third Law of Motion, which states that for every action, there is an equal and opposite reaction. This law enables a quadcopter to ascend and navigate through the air by generating lift through its propellers.

To generate lift, a quadcopter's propellers spin, pushing air downwards and creating an upward force, or lift, on the quadcopter. The faster the propellers spin, the greater the lift and vice-versa.

The spinning of the propellers also generates torque, which can destabilize the quadcopter if not properly managed. However, engineers counteract this effect by designing two of the quadcopter's propellers to spin clockwise and the other two counter-clockwise, canceling out the opposing torques and stabilizing the quadcopter.

Quadcopters can do three things in the vertical plane: hover, climb, or descend. To hover, the net thrust of the four rotors must be exactly equal to the gravitational force pulling the quadcopter down. To climb or descend, the thrust of the rotors must be greater than or less than the weight and pull of gravity, respectively.

The movement on the remote control sticks sends signals to the central flight controller, which then directs the motors to increase or decrease speed. This complex interplay of components enables the quadcopter to achieve flight.

To pitch forward or backward, the right stick is pushed forward or backward, adjusting the drone's forward or backward tilt. This is achieved by decreasing the speed of propellers #1 and #4 and increasing the speed of propellers #2 and #3.

Because most quadcopters are symmetrical, there is no difference between moving forward or backward. To fly forward, an increase in the quadcopter motor rpm of rotors 3 and 4 (rear motors) and a decrease in the rate of rotors 1 and 2 (front motors) is required.

Here's a summary of the quadcopter flight principles:

These principles work together to enable a quadcopter to achieve flight and navigate through the air.

The central flight controller is the brain of a quadcopter, processing pilot inputs and communicating with motor ESCs to control movement and stability. It's a crucial component that makes nuanced movements possible.

The central flight controller receives data from various sensors, including IMU, Gyroscope, GPS modules, and obstacle detection sensors, if the quadcopter has them. This data helps the controller make computation calculations using programmed flight parameters and algorithms.

Most flight controllers have a lot of features, including dual IMUs for redundancy and safety features like Return-To-Home. The DJI N3 Flight Controller is an example of a central flight controller that has a lot of features and can work with various motors.

A quadcopter's control system relies heavily on coding and symbols to communicate with the aircraft's components.

In the article, we discussed how the flight control system uses a specific coding language to send commands to the ESCs, which then convert the code into electrical signals.

The symbols used in the code are crucial for the quadcopter's stability and navigation.

These symbols are often represented by hexadecimal codes, which are converted into binary code for processing.

The quadcopter's control system also uses a protocol called SPI (Serial Peripheral Interface) to communicate with the sensors and other components.

SPI uses a specific sequence of bits to transmit data, ensuring that the quadcopter's systems are synchronized and functioning correctly.

The use of codes and symbols in quadcopter control systems allows for efficient communication and precise control over the aircraft's movements.

The central flight controller is the brain of the quadcopter, processing pilot inputs and communicating with each motor's Electronic Speed Controller (ESC) to control the propellers' rotation. It receives data from various sensors, such as the IMU, Gyroscope, GPS modules, and obstacle detection sensors, to make computation calculations and send data to the ESCs.

The flight controller is responsible for controlling the nuances of movement, including roll, pitch, yaw, and throttle. It's a crucial component that enables precise aerial maneuverability.

The flight controller can encompass multiple features, including dual IMUs for redundancy and safety features like Return-To-Home. Some examples of advanced flight controllers include the DJI N3 Flight Controller, which has a wide range of features and compatibility with various motors.

In addition to the flight controller, the Electronic Speed Controller (ESC) plays a vital role in controlling the quadcopter's movement. The ESCs adjust motor speeds to control the propellers' rotation, and they come in different classes, such as brushed and brushless motors.

Brushless motors are more efficient and faster than brushed motors, with the ESCs necessary to turn on and off the coils in a timed manner to keep the motor running. Brushless motors have two subclasses: inrunners and outrunners, with the main difference being the rotor and stator configuration.

Here's a brief overview of the components in a drone motor and propulsion system:

The throttle control system is responsible for managing the drone's altitude, with the left stick used to increase or decrease altitude. Proper throttle management is crucial to maintain desired altitude and prevent crashes.

To roll a quadcopter, you push the right stick to the left or right, adjusting the drone's lateral orientation.

The flight control system decreases the speed of propellers #3 and #4 while increasing the speed of propellers #1 and #2 for a roll to the left.

This imbalance causes the drone to tilt and roll to the left, creating lateral force for sideways movement.

To maintain altitude during a roll, the speed of all four propellers must be increased to counteract gravity.

The speed of propellers #3 and #4 must be decreased and the speed of propellers #1 and #2 must be increased for a roll to the left.

This is the opposite of what's needed for a roll to the right, where the speed of propellers #3 and #4 would be increased and the speed of propellers #1 and #2 would be decreased.

A roll is controlled by pushing the right stick to the left or right, which adjusts the drone's lateral orientation.

The propellers' speed imbalance creates the lateral force needed for sideways movement, but it also requires increasing the speed of all four propellers to maintain altitude.

This is a key concept to understand when flying a quadcopter, as it can be tricky to get the hang of at first.

Yaw is controlled by the left stick, moved left or right. This causes the drone to rotate or turn to the left or right.

For a clockwise rotation, the speed of propellers #2 and #4 is decreased, while the speed of propellers #1 and #3 is increased. This action uses the differential in propeller speeds to generate rotational movement without altering the drone's position in space.

The gyro is the most accurate and reliable sensor for measuring yaw, as it's not affected by vibration and linear motion. However, gyros do suffer from drifting, where small errors add up to make huge problems.

The magnetometer is used to calculate yaw angle, replacing the accelerometer and correcting gyro drift. This ensures accurate yaw measurements, even when the drone is moving or vibrating.

Building a quadcopter can be a fun and rewarding project, but it requires careful planning and attention to detail. You'll need to choose the right frame, which is the backbone of your quadcopter and will influence its size, weight, and payload capacity.

The type of material used for the frame will also affect its performance, with carbon fiber offering strength and lightness, while aluminum and plastics are better suited for beginners and budget builds. The size and weight capacity of the frame will also determine the size and power of the motors and propellers you'll need.

To power your quadcopter, you'll need a battery that can match its power requirements. Lithium Polymer (LiPo) batteries are a popular choice due to their high power output and rechargeability.

Here's a list of the essential components you'll need to build a quadcopter:

The choice of electronic components, such as ESCs and the flight controller, will depend on your specific needs and requirements. Some flight controllers are designed for beginners, while others offer more advanced features and customization options.

When assembling your quadcopter, it's essential to follow a step-by-step process to ensure everything is properly connected and configured. This includes attaching motors to the frame, connecting ESCs to the motors and PDB, and installing the flight controller.

Finally, after assembly and configuration, you'll need to perform a test flight to ensure all systems are working correctly and make any necessary adjustments.