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Useful information about quadcopters , multicopters and drones
There is probably no aircraft as fascinating as a quadrocopter. Not long ago, everything started very small. The first model airplane copters were developed by ingenious electronics and further optimized in cooperation with experienced model flyers.
After the first well-flying copters appeared on the market, the scene blossomed. Now there is a suitable copter for every purpose and for every wallet. It is sometimes surprising what features are offered at an entry-level price class.
What is a quadrocopter?
How does a quadrocopter work?
How is a quadrocopter controlled?
What types of quadrotor helicopters are available?
What do you have to pay attention to when purchasing quadrocopters?
Frequently asked questions about quadrocopters and multicopters
What is a quadrocopter?
A quadrocopter is a helicopter-like model that can start and land vertically, just like a helicopter. In contrast to a helicopter with a technically complex mechanics, four horizontally arranged propellers are sufficient for a quadrocopter. These propellers are each driven by their own motor. The mechanical components are thus limited to a minimum. The electronics with their position and acceleration sensors are much more complex. Only because of this clever sensor system can a quadrocopter hover stably in the air.
Larger copters with high load capacity are partly equipped with six or eight propellers. In this case, the aircraft will be referred to as hexacopter or helicopters. But drones, multicopters or simply multicopters are also common designations.
How does a quadrocopter work?
A helicopter requires a tail rotor so that the fuselage does not turn in the opposite direction of rotation of the rotor.
Four horizontal propellers generate a downward-aligned air flow so that a quadrocopter can fly. If the air flow is strong enough, the model is lifted up.
However, a rotating propeller or rotor also generates a torque on the engine or on the complete aircraft. When the propeller turns to the left, the aircraft wants to turn to the right. This is also why many helicopters need a tail rotor.
Turning the main rotor (blue arrows) generates a torque on the fuselage (red arrows). The torque is balanced by the effect of the tail rotor (green arrow).
Depending on how much the compensation is made, the targeted rotation of the helicopter can also be controlled via the tail rotor.
This torque effect also occurs with a quadrocopter. That's why you use a simple but ingenious trick:
Seen from above, two propellers run clockwise and the other two propellers run counter-clockwise. This causes the torques that affect the model to mutually increase and the quadrocopter does not need an outlayer with a tail rotor for stabilization. In addition, the propellers are arranged diagonally to each other with the same running direction.
The only drawback: Only two different propeller designs are required so that the air is always transported downwards, regardless of the direction of rotation. Especially during maintenance work, or when the propellers have been unscrewed for transport, you have to pay close attention to the rotational direction of the motors or propellers during installation.
By the way:
The angle of the individual propellers to each other does not matter. Because when flying, the motors never have the same speed, which causes the angle settings to change continuously. It is much more important that the air screws are precisely balanced and turn without vibration.
Always two diagonally arranged propellers have the same running direction.
If all four propellers are accelerated evenly, the quadrocopter will lift off at a certain propeller speed. If the speed is then reduced slightly, the quadrocopter hovers at a constant altitude.
Due to further changes in the hover speed, the quadrocopter rises or reduces the flight altitude. Built-in position and acceleration sensors detect minimal changes in the flight attitude and adjust the speed of the respective motors immediately. This means that the Multicopter can always maintain its horizontal and stable flying position.
Due to the symmetrical design, it is often not easy to recognize the current orientation of the model in flight.
Especially when the model is small and far away. For this reason, the manufacturers like to use propellers with different colors.
In the example image shown, the front propellers are red and the rear blue.
How is a quadrocopter controlled?
In order to fly forwards, for example, from hover flight, the speed of the front propellers (A and B) is reduced slightly and the speed of the rear propellers (C and D) increased slightly. This causes the copter to tilt forwards slightly at first. The air flow of the propellers is thus slightly toward the rear and pushes the quadrocopter forward.
For a flight backwards, the speed changes of the propellers occur exactly opposite. The speeds of the front propellers (A and B) are increased and the rear propellers (C and D) run slower. The quadrocopter already flies backwards.
The control to the right and left is carried out according to the same procedure. Only that the speeds of the two left and right propeller pairs (A and C) and (B and D) are changed now.
The propellers have been cloned for the exact assignment.
To allow the quadrocopter to rotate in the air on the spot, simply change the propeller speeds in the same direction of rotation.
If the rotational speed of the propellers (A and D) rotating clockwise is increased and the rotational speed of the propellers (B and C) rotating anti-clockwise is reduced to the same degree, the total driving force remains the same. The quadrocopter will continue to hover at a steady altitude.
However, due to the different propeller speeds, the torques that affect the quadrocopter are no longer balanced. It therefore begins to turn to the left. This rotation around the vertical axis (thought line running through the quadrocopter from top to bottom) is also called "yaw".
If the propeller speed changes in the other direction, the quadrocopter turns to the right.
The flight in a certain direction, the desired flight altitude and the rotation of the quadrocopter is controlled with the help of the two joysticks on the remote control transmitter or controller. Some copters also offer the option of connecting to the smartphone via WiFi. In this case, the smartphone can also be used to control the Copters.
What types of quadrotor helicopter are available?
Quadcopters are differentiated according to their application area. Where the transitions between the individual areas are flowing.
Compact beginner's quadrocopter with child-friendly remote control.
The entry into the fascinating world of quadcopters is already possible without great financial effort. This is why these models are often used as a gift for children. It is important that the remote control is designed for small children's hands and that the propellers have protective guards. In addition, an adult should supervise the flight operation in order to be able to intervene if necessary.
Often entry-level models already have a built-in camera. This allows you to get a bird's-eye view of the first experiences with photos and videos. However, in most cases, the resolution of the camera is not particularly high and the videos are slightly blurred by a restless flying style. But still, filming and photographing is a great addition to flying.
And so that the flying pleasure of the young pilots is not too short, many beginner copters can fly spectacular flips.
Typical leisure quadrocopter with GPS receiver and a gimbal camera mount for shaky video.
In the meantime, quadcopters are also used to make particularly great photos or video recordings of leisure activities. The quadcopters offer very good image quality and are easy to control. Due to the higher weight, they have a much quieter flight position than the lower-cost beginner's models. Camera stabilization systems (gimbals) provide for wobble-free photos and videos.
By receiving navigation satellites, the aircraft can orient themselves in the room, even in the case of wind, automatically hover in place and perform autonomous flight maneuvers.
Especially clever: Some units can also be folded together in a compact way and thus require only very little space in your holiday luggage or in your backpack.
Industrial drone with 6 rotors, which can be used for film and photo production as well as for inspection tasks.
The name is a little misleading, because these high-end aircraft are also used successfully in crafts and agriculture as well as in public authorities. But photographers and reporters also enjoy working with these systems.
The main focus of these drones is to place a camera in a position that would be difficult or unreachable from the ground. This makes the exact inspection of buildings or fireplaces a child's play. An elaborate scaffolding or dangerous climbing activities are no longer necessary for this.
The flying camera stands are also ideal for film and photo. Combining different flight and film modes creates stunning shots that would otherwise be possible only with extraordinary hohem.
Because the user normally concentrates fully on the camera images, flying is a secondary matter. For this reason, most of the control is taken over by the electronics in the drone. In addition to a GPS receiver, a compass and extensive sensors for position and obstacle detection are also on board for autonomous flying.
Race copter is compact, stable and really fast on the way.
Race Copter or race drone are pure fun devices that require a lot of sensitivity and strong nerves. Because these drones are moved at maximum speed on a race track with gates and pylons. For this purpose, the race drones are equipped with cameras that transmit their images live to the FPV goggles of the pilots. The pilots at the remote control transmitter then experience the racing happening quasi from the cockpit view. But even for spectators who look more or less at the events from the outside, it is always fascinating how fast and agile these racers are.
Ready-made race copters are offered for the introduction to the scene, with which one can already experience the real racing feeling. Experienced model builders build their own racing equipment with the highest quality technology, in order to find the best setup for their requirements. These race copters are also extremely stable, so that they can have surprisingly little racing accidents and crashes.
What do you have to pay attention to when purchasing a quadrocopter?
Which model you choose ultimately depends on several factors that we have listed here for you:
Purpose and application area
For people who simply want to test flying with a quadrocopter, entry-level models are ideally suited. However, it should be ensured that the small and light copters are only partially suitable for outdoor use due to their wind sensitivity.
Unfortunately, selecting the right model is not so easy for a craft for leisure activities or even for commercial use. You have to think carefully about what was to be done and what functions were needed. While hikers and mountaineers prefer more compact specimens, a roof-top or chimney sweeper will pay more attention to simple operation and precise hovering flight. Photographers and videographers, on the other hand, pay attention to image quality and long flight times.
The cameras in beginners' Copters often read a few wishes unfulfilled in terms of video quality or lens alignment. Those who value quality here should always choose a model with electronic image stabilization. It is even better if the camera itself is mechanically stabilized via a gimbal. This will prevent possible rocking of the Copter from being transferred to the camera mount.
In addition to the resolution of the camera, the storage of photos and videos also plays an important role. If the storage is not done on a flying SD card, transmission errors can be noticeable as image interference.
The function is called GPS, but in addition to the navigation satellites of the Global Positioning System, the Russian Glonass navigation satellites are often received and evaluated. This allows the quadrocopter to maintain its hovering position very precisely even in the wind and perform autonomous flight maneuvers if necessary.
Drones without GPS also have a stabilization system, but this only refers to horizontal alignment in flight. They cannot be recognized if they are offset to the side, e.g. by wind.
GPS only works outdoors. In indoor use, the signals of the satellites are attenuated, whereby GPS-based functions will not function or no longer function reliably.
A good obstacle detection plays an increasingly important role. Especially when automatic flight maneuvers such as the follow-up function or the automatic return function are used.
However, this function is often very helpful even in normal flight operation. After a certain distance, it is very difficult to correctly estimate the spatial depth and thus the actual distance to an obstacle.
The attainable flight times are often the sticking point for beginner models. Because the rather small models are not able to carry large and heavy batteries. Thus, the flying fun often ends after 5 minutes and the flight battery has to be recharged. Therefore, it is recommended to select a model for which the rechargeable batteries can also be charged outside the model. Thus, you can continue to fly with a replacement battery while the previously used battery is filling up with new energy on the charging cable.
Larger copters usually have longer flight times and some additional rechargeable batteries are included in the delivery. If not, additional batteries are available as optional accessories.
Another purchase criterion that cannot be underestimated is the price. However, every user has to decide for himself whether he can do without certain features in favor of a lower price. In case of doubt, it is worth contacting a specialist consultant at a Conrad Electronic branch and clarifying all open questions personally.
Other frequently asked questions about quadcopters
What was a gimbal?
A gimbal is a stabilized camera mount. This prevents the drone from rocking during rapid changes in direction during flight. The thus generated quiet camera guidance then provides for absolutely wobble-free videos.
What was to be observed when using drones?
The use of drones is subject to legal regulations, which are precisely regulated in the current drone regulation. There must also be valid insurance cover. If the use of drones is not covered by the existing liability insurance, a suitable insurance can be taken out via the German Model Flying Association.
What was FPV?
The abbreviation FPV stands for "First Person View" and means "View from the cockpit". For this purpose, the models are equipped with front-facing cameras that transmit their signals to monitor or FPV goggles. The user then controls his model according to the camera images and has the impression that he himself is sitting in the cockpit.
What was headless mode?
When the quadrocopter turns in hover flight, the directions of movement will change from the perspective of the model pilot. This is particularly noticeable when the quadrocopter is facing the pilot after half a turn with the front. When the transmitter is steered to the left at this moment, the model moves to the right from the pilot's perspective.
In headless mode, it does not matter in which direction the front of the model is aligned. When the transmitter is steered to the left, the quadcopter always flies to the left from the pilot's perspective.