Not so long ago, to send an aircraft, even its model, into flight, an accurate calculation of aerodynamics, engineering calculation, as well as the remarkable skill of the person who controls it, were required. But with the development of electronics, it has become technically possible to make almost anything fly, as long as it has sufficient engine thrust.
Thanks to this, the wide distribution of radio-controlled quadrocopters and multicopters became possible.
Quadcopter in flight
So, let’s start with what is, for example, a typical quadcopter. This is a model with four electric motors, each of which drives a propeller, the thrust of which is directed downwards. Half of the engines, at the same time, rotate in one direction, half in the other. Due to the difference in the speed of rotation of the engines and their thrust, the quadrocopter is tilted and rotated around the vertical axis. All this requires efficient motion and position sensors, as well as precise motor control. Actually, from the complexity of control systems and envy of the class of the device.
In addition, there are so-called multicopters, that is, devices with more than four propellers. Generally, multicopters have better payload capacity and flight stability.
So, what characteristics will help to distinguish different classes of these devices?
Features of control and management
In our opinion, it is control and management that primarily distinguishes expensive and cheap quadrocopters.
First of all, it is worth understanding how the operator controls the drone.
The usual case is when control is carried out using the transmitter of the equipment. For full control, four axes are needed: total thrust (height), turn, tilt forward-backward, tilt left-right.
DJI Phantom transmitter with tablet
At the same time, the transmitter itself should be comfortable enough. The small-sized options, reminiscent of a gamepad, are worse than the full-sized options in this criterion. For models with camera gimbal control, camera control is required.
Sometimes, a smartphone with a special program connected via Wi-Fi to the quadrocopter can be used as a transmitter.
In addition to the type of control panel, the presence of electronic assistants matters.
In budget models, in fact, “manually” you have to control the movement of the device in the air, which requires a certain skill and skill.
On more complicated models, the so-called hovering mode appears, thanks to which “taxiing” is not required to hold the device.
The most advanced models have a more complex controller that implements the following functions:
- GPS positioning. Quadcopters can even have an autopilot function, that is, flying along waypoints. And such a function as a return to the starting point is a necessity for expensive models.
- a large number of control modes. For example, a quadcopter can be located on one side of the operator, or it can maintain its orientation relative to the cardinal points.
- setting flight parameters on the computer. As you can understand, the quadcopter controller performs the function of flight stabilization, limiting the range of its movement. Accordingly, by connecting the quadcopter to a computer, you can change the level of these restrictions (for example, the angle of inclination), making the behavior of the model more or less aggressive.
For example, DJI releases the Naza‑M controller, which is installed in its own quadcopters, or sold separately for use in “self-assembled” drones.
DJI Naza‑M Quadcopter Controller
Finally, the obstacle avoidance function is very useful, thanks to which you will not smash your dear flying friend against the wall. It is implemented using cameras for viewing the surrounding space and operates in the visible range.
Together with them, ultrasonic locators can be used, as in bats.
Ultrasonic position sensors quadcopter DJI Phantom 4 Pro
Quadcopters and multicopters come in a variety of sizes.
Conventionally, they can be divided into three classes:
- Large quadcopters. These models are designed for cargo transportation, reconnaissance, or aerial photography on large cameras. The price of such devices is always high, since in this class there are no quadcopters-toys designed solely for entertainment.
- Medium. This is the most common class, which has the best combination of price and features. There are models for aerial photography and for simple “flying” models. The price of budget and expensive models can differ by an order of magnitude, and the functionality also differs accordingly.
- Compact, “mini” models. This class does not feature high camera image quality or long flight times, but is great for indoor flying (home, office, gym). They do not require a lot of space for transportation and use, but they overcome the wind worse due to their size. In addition, an ultra-compact quadcopter is less visible at a distance, and because of this, it will be more difficult to distinguish between its rear and front.
In principle, a quadcopter may not have a camera, and then it will be possible to control it normally only within sight.
The next stage is when the camera is integrated into the quadcopter. It is clear that such a solution is budgetary, the camera is not protected from vibration, and therefore the picture quality will leave much to be desired. Such cameras are typical for amateur and racing models.
Quadcopter Parrot Bebop Drone with integrated camera
In some cases, the camera can rotate relative to the quadcopter body, but only before the flight, and not during it. This solution is slightly better than the previous one, but still far from ideal.
The most advanced option is a camera on a stabilized gimbal that can be controlled remotely, that is, the camera can turn in flight. As a rule, such cameras have a good matrix, optics and shoot video in high resolution. The appearance of remotely controlled gimbals on the market has become one of the factors in the spread of aerial photography from quadrocopters.
Camera and gimbal DJI Phantom
Of course, what happens in the video recording and photos from the camera is also important.
On budget models, the video is simply recorded on a memory card, and you can watch it only after the drone “lands”.
But, of course, it is much more interesting when the picture is not only recorded on a memory card, but also transferred to the operator. This allows you to better control the flight and the recording itself. All the great films shot from a quadcopter could hardly be made without watching the image during the flight.
Flight time and distance
This is one of the easiest characteristics to understand, but not the easiest to implement.
With the flight range, everything is more or less clear — a large-capacity battery is enough, plus efficient engines. Increasing the reserve of battery capacity is one of the possible ways to tune factory models. However, it is clear that the thrust of the engines to lift additional batteries must be considerable.
But with a range it is more difficult, because you need not only to transmit control signals from the remote control, but also to receive a picture from the camera. However, for example, in DJI professional models, the control range is 5 kilometers (in Europe, the same models determine their location and refuse to fly further than 3.5 kilometers).
There are two types of motors used in quadcopters: brushed and brushless. Brushless ones are better — they have less friction between electrical parts, and therefore they are much more durable. However, they are also more expensive.
So, quadrocopters have a large number of characteristics and features, but despite this, there are not so many functional classes.
Let’s talk about what classes of quadrocopters exist.
As the name implies, they are significantly limited in capabilities.
First, they have an average flight time of about 10 minutes.
It uses commutator motors, which, as we know, are not very durable.
Of course, the built-in cameras on such quadrocopters do not differ in particular image quality.
One of the most popular manufacturers of such models is Syma. It offers a huge range of drones at a very attractive price.
Syma X5 quadcopters are one of the most popular
Of course, you need to understand that budget quadcopters can serve either for entertainment or as a transitional stage to more serious classes.
Quadcopters for aerial photography
Quadcopter Gopro Karma
It was with the advent of this class of devices that quadcopters became as popular as they are now. To be precise, DJI, with the famous Phantom quadcopter, was the first to offer an out-of-the-box solution suitable for aerial photography. First of all, this became possible thanks to the Naza‑M controller, which perfectly stabilizes the quadcopter in the air, as well as the perfect camera suspension, which allows you to move the camera in flight, plus it additionally compensates for the vibration of engines and propellers.
These models are most often assembled by hand from individual components, and have high speed, maneuverability and the most lightweight yet durable construction. To achieve these qualities, blades and a frame made of carbon fiber are used.
RTF racing quadcopter Walkera F210
Quadcopter races are held in FPV (First Person View) mode. To do this, the operator is put on a special helmet — glasses, on which the picture from the drone’s camera is displayed. The camera is rigidly fixed, but not from a bad life, but for better flight control and simplicity (lightness) of the design.
For example, the speed of the Walkera Furious 320 racing quadcopter can reach 33.3 m/s (for comparison, the DJI Phantom flies at a speed of 20 m/s).
The variety of quadcopters on the market is very large, but despite this, the choice is quite simple to make if you are guided by reasonable considerations.
Despite the fact that the fundamental structure of quadrocopters is the same, they are quite clearly divided into classes. Therefore, knowing your budget and reading our article, you will make the right choice.
Mini glossary of terms
RTF (Ready To Fly) — an aircraft model or quadrocopter, sold fully assembled and complete enough to fly
suspension — a device responsible for mounting, movement and stabilization of the quadrocopter camera.
Collector motor — an electric motor in which the alternating current supply to the windings is provided by a mechanical contact of the collector. The disadvantage is the presence of friction in the collector contacts, as a result of which they wear out and the engine fails.
Brushless motor — an electric motor in which the alternation of the current supply is provided by external devices. It is more durable than the collector and has a higher efficiency compared to it.