How do I build a small drone

How to build your own multicopter drone

Patrick Leiner

Building a copter yourself is not as complicated as you might think. If he then also flies without any problems, it gives a great feeling of satisfaction.

EnlargeIndividual parts of a self-made drone

Whether it's the small toy copter, your own racer drone or a large octocopter for creating image and video material: The fascinating multicopter technology is currently the hit in the field of hobby and professional model making and exerts a magical attraction on everyone select those who are interested in aviation and aircraft as well as new technology and technology trends. It has never been easier and cheaper to deal with such great aircraft technology and to take the controls into your own hands to really take off.

However, if you want to deal more intensively with the technology, it is recommended to plan your own copter from scratch, calculate it, order the right components and then assemble the entire multicopter project. Anyone who plans and realizes their own multicopter gets to know the entire technology from the ground up. After the construction phase, flying your own aircraft yourself (attention: you are not allowed to do that everywhere!) And optimizing it gives you a really great feeling of satisfaction. Anyone who plans and realizes their own multicopter gets to know the entire technology from the ground up.

Which components do I need to build my own multicopter?

There are many different components, component sizes and performance specifications, operating parameters and interface specifications that must be taken into account when planning and implementing a do-it-yourself copter project.

It's not quite as difficult as some people imagine building a multicopter yourself. First of all, I have to know which components I need for my copter and how they are calculated (designed).

frame

The frame is the base of the copter and is selected first. There are some criteria here in terms of material and size. For example, the size of the frame (measured from the motor shaft to the opposite motor shaft) plays a very important role when it comes to the later flight characteristics and of course the intended use. A small frame gives the copter an agile and manoeuvrable flight characteristic. Large copters fly very quietly, stably and energy-efficiently.

Flight controller

The flight controller, also known as flight control, is the heart of every multicopter. With the help of various sensors, it calculates the current flight position and stabilizes the aircraft by comparing actual and target values ​​via the control of the ESCs (Electronic Speed ​​Controller). So the copter can stay very calm and stable in the air despite its physical instability.

EnlargeFlight controller CC3D - runs with the Libre pilot system

With this important component, however, there is always the problem of which system to use. Here you are spoiled for choice, so to speak. There are a number of systems on the market, each with its own advantages, disadvantages, and quirks. DJI-Naza, MultiWii or CC3D are only a small part of the entire market.

When choosing a flight controller, it is therefore important to pay attention to the respective software and connection options. Nobody wants to build an octocopter and later find out that the flight controller only supports 6 motors.

Motors and propellers

Today, 99.9 percent of the brushless motors are used in multicopter aircraft. These have a number of advantages and offer high performance with a relatively long service life. When selecting a suitable motor, there are many details and parameters to be considered. Here you are confronted with size specifications such as 2208, performance data such as 750 KV or - optimally - with the maximum thrust, about 800 grams of thrust.

EnlargeDirect mounting of a carbon propeller

Based on these specifications, the performance of a do-it-yourself copter project is adjusted and a rotor combination (motor + propeller) is selected. The propeller plays one of the most important roles in the power chain because it brings the engine's power into the air. A propeller is defined by two important pieces of information, the diameter and the pitch. The ratio of these two parameters is called the H / D ratio and provides information about the purpose and performance of the propeller.

ESC (Electronic Speed ​​Controller)

The ESC is used to control the brushless motors. It receives its speed requirement or rotor speed, so to speak, from the flight controller and implements this information. For use in a multicopter, special software packages are required on such an ESC in order to cope with the rapid speed changes in the multicopter area. SimonK is just a piece of software that can be used for this.

LiPo battery

The battery of a multicopter drone must also be chosen carefully. It makes a not inconsiderable contribution to the total weight of the aircraft and consists of several lithium polymer cells that are combined to form a battery pack. The number of cells (S) of a LiPo defines the nominal voltage of the battery. For example, a LiPo with 3 cells (3S) has an average voltage of 11.1 volts (3.7 volts per cell). This information is also very important when selecting other components such as the motors and ESCs.

EnlargeLithium polymer battery with voltage monitoring

LiPos have a high energy density (stored energy per unit weight), but may only be used within the intended performance limits. There are a few things to consider here, because operation outside of these specifications directly resents the battery and there is a risk of fire or, in the worst case, explosion.

RC system

Each copter is controlled via a remote control. Here, too, it must be taken into account what the multicopter "should" be able to do. Some RC systems have 6 control channels, others 8 or more. At least 4 channels are required to control all 4 flight axes of the aircraft. If I want to switch between different flight modes during the flight, another channel is required.

When selecting the right receiver, you must also ensure that it fits the remote control. Very few systems can be combined with each other, so you should always find out beforehand which receivers are compatible with your own remote control.

Additional equipment and tuning parts

If you want to pimp your drone a bit, you will first encounter FPV flying (first person view) in the multicopter area. With the help of an FPV camera, a video transmitter, a receiver and FPV glasses (or monitor), the pilot gets the feeling that he is steering the copter himself from the cockpit.

Additional modules such as a telemetry system for the live transmission of flight data or a camera system with a gimbal suspension for creating vibration-free videos can be attached to and connected to a copter.

In summary, we need the following components to build a multicopter yourself:

  • Frame

  • Flight controller

  • Engines

  • Propellers

  • ESC (motor controller)

  • battery pack

  • RC system

  • Additional components such as FPV equipment, camera and suspension or telemetry system

Was it fun? Then you can go ahead and build an autonomous rover drone. Patrick Leiner explains how this works in the article "Build your own autonomous rover vehicles".