Introduction

Call them what you want, in fact, the name is still much debated, but drones have captured people’s attention. We’ve all heard about how these machines will hurtle across the sky to deliver pizzas and packages, take great pictures and perform a lot of other tasks.
We have also seen how the word has been used to describe unmanned, military vessels, which controversially determines life and death – but it is another matter. But what can you actually do with drones? How do you choose the right drone? How does a drone work? How do you maintain a drone? How many types of drones is there? What are the rules for flying with a drone? etc. This text will be informative for some questions you may have, while it will also point you in the direction of where to look for the answer yourself.


BASIC KNOWLEDGE OF DRONES

History of Drones

Multi-copters (also called drones) was a bit of a subculture until a small business that really made entertainment equipment for cars, caught the world’s attention with their AR.Drone in connection with the International Consumer Electronic Show (CES) in Las Vegas in 2010.

The Parrot AR.Drone was a 22-inch multi-copter and a genuine consumer product that was ready to fly as soon as it was taken out of it’s box. The drone was made of nylon and carbon fiber and had a removable airframe of lightweight polystyrene. It also had a small front mounted camera built-in. However, this drone was special because it could be controlled from an iPhone via Wi-Fi, which was fascinating. The journalists who attended the CES had only just become accustomed to the world of iPhone Apps (a technology which at that time was only 18 months old), and a remote-controlled drone appealed to everyone. The drone attracted attention from Apple and journalists from the telecom and computer games industry. People from the photographic industry were attracted to the flying camera (despite the fact that the quality wasn’t very good) and so on. Overall, the AR.Drone got a lot of press coverage at the time.

Chris Anderson, the editor of the technology magazine wire at the time, started to create the ArduCopter project, and in connection with this, he also created the networking website DIYDrones.com, to describe and support the project. DIYDrones.com has since added a commercial leg – namely 3DR Robotics, which sells drones in kit form; ready to be built. However, 3DR doesn’t have the market for itself. DJI from China had in 2013 established a large variety of components as well alongside with probably the most respected quadcopter on the market at that particular time, the Phantom (series) quadcopter.

The launch of DJI’s ‘Phantom Quadcopter ‘ was the start of their big success in the present drone market. To increase the market for drones, the DJI realized that they had to appeal to a group that had a real need for corporate drones and not only to amateurs.
This group was creative people who worked with aerial photography and video recordings. DJI decided to make the Phantom easier to use, and improved the drone’s ability to take pictures, and so it was the beginning of people’s perception of drones and what they could be used for and what they were/could become able to do.

Military Drones

When people hear the word ‘drone’, the first thing they think of is often the devastating use (abuse?) of powerful military aircraft. The best known series of these is the General Atomics MQ-1 Predator, which officially was first used for the first time in 1995. But it was not the first time that the military showed interest in unmanned aircraft.

The earliest historical source that refers to unmanned military aircrafts dates back to 1849, when Austrian forces tried to besiege Venice. Austrians filled balloons with bombs, and when the wind carried them over Venice, the bombs triggered. There is a long line from that technology to today’s use of unmanned aircraft, which more directly can be traced  to WW1. In 1917, the English engineer Archibald Low, who wore head of the Royal Flying Corps Experimental Works, built a radio-controlled aircraft that became known as “Ruston Proctor AT”. The intention was to place explosives on the plane and steer it toward the goal, which made it the first cruise missile in history.

Israel’s invasion of Syria in 1982, started a more aggressive use of unmanned aircrafts (UAV – Unmanned Aerial Vehicles). Israel used among other drones as electronic decoys and jammers, which helped to secure them the victory over the Syrian air force. After this success, it was almost Inevitably that other military forces wouldn’t take these aircrafts more seriously. This led to more advanced drones, which is able to fly semi-automatic and carry missiles that can be fired through remote controls.The rapid development of this type of vessels has given some governments new opportunities, but military drones are today still very controversial.

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The development of Multi-Copters

Just like the UAVs has a longer history than most envisioned, the multi-copters also has a significant heritage. In addition to balloons and Zeppelins, multi-copters (including manned Quadcopters) has conducted some of the earliest vertical launches and landings in history. 

 

Gyroplane no 1
1907 – Gyroplane No. 1

As early as in 1907 – more than 30 years before the first helicopter – flew the French brothers Louis and Jacques Breguet what was essentially a large Quadcopter. Their so-called Gyroplane 1 was “controlled” by Monsieur Volumard. Although the vessel was able to carry its own weight, they had to be controlled with rope from the ground. It was designed with four blades for each rotor, and each blade was eight meters long.

Curtiss-Wright-VZ-7
1958 – Curtiss-Wright VZ-7

The Curtiss-Wright VZ – 7 (also called the flying jeep), was used by the US military between 1958 and 1960. The VZ-7 had a fuselage with the pilot’s seat, fuel tanks, and flight controls. On both sides of the fuselage, the propellers were attached, unshrouded (the aircraft did originally have shrouds, but these were later removed). There were 4 propellers in total. The VZ-7 was controlled by changing the thrust of each propeller. The flying platform was maneuverable and easy to fly.

 

De Bothezat quadcopter
1922 – De Bothezat

The de Bothezat helicopter was an experimental quadrotor helicopter built for the United States Army Air Service by George de Bothezat in the early 1920s, and was said to be the first successful helicopter. In 1923 succeeded the Bothezats multi-copter to stay in the air for 2 minutes and 45 seconds, and then  land safely again. Although its four massive six-bladed rotors allowed the craft to successfully fly, it suffered from complexity, control difficulties, and high pilot workload, and was reportedly only capable of forwards flight in a favorable wind. The Army canceled the program in 1924, and the aircraft was scrapped.

 

X-22 drone
1966 – X- 22

One of the most significant development happened with the X-22 in 1966. It had a computer on board to improve the stability, which was made possible by changing the angle of the propellers. Although the first X-22 crashed, nothing happened with the pilots. The Second edition of the vessel performed in the air for over 100 hours. Although it could not fly with the planned speed of 525 km per hour, it was in operation until 1988.

 

Cierva W.11 air horse
1948 – Cierva W.11 Air Horse

When they started testing this drone in 1948, the Air Horse was the largest rotorcraft, anyone had ever seen. All three rotors moved in the same direction. The aircraft had to angle the motors in opposite directions. This low-tech solution was used to prevent the machine from rotating itself.

 

MV-22 Osprey
1989 – MV-22 Osprey

The V-22 was first tested in 1989, but has since been used for active duty by the US Navy in 2007 – and later in the Air Force in 2009. Like the X-22, the MV-22 has adjustable rotors that allow for VTOL and flying at high speed. It can also be refilled in the air. The aircraft can land vertically like a helicopter or fly like an ordinary propeller aircraft when it has gained altitude. It is designed to combine the functionality of a conventional helicopter with the long-range, high-speed cruise performance of a turboprop aircraft.

 

Today

The idea of controlling individual motors without the pilot is what has made modern multi-copters possible this day. Small radio-controlled Quadcopters have poor stability, and therefore, is an electronic control unit, the only way to fly them. The essential component for flying these is a gyroscope – a technology that has been gradually improved in parallel with the vessels that depend on them. Although they were small enough to be used on aircraft during the World War 2, they got even smaller during the missile era in which they filled 2.5 cm in diameter and weighed about 85 grams. Since the 1990s, digital MEME-gyroscopes has become an integral part of electronic circuits, and it is exactly the same technology that makes smartphones know how it is held. These light gyros also made it possible for ordinary pilots to control the first RC helicopters. With gyros in the toolbox, the only thing that was missing were multi-copters to put them in.

 

How does multi-copters fly?

Multi-copters are different compared to traditional aircraft. Forward momentum is essential for major parts of today’s air crafts. Multi-copters are much more flexible – only the propeller blades need to be aerodynamic, and control is achieved by small changes in their rotation.

The wings of a traditional plane are curved shaped and it smashes into the air when they hit it. The shape of the wings means that the air above the wing is pushed away, whereby the pressure above the wing is less than under the wing, where the air is not disturbed. As soon as the pressure difference between the air above and below the wing is large enough, the wings are pushed upwards. This works only when the wings move forward fast, and it creates the needed air, and therefore it is also necessary to have long runways. For helicopters, the same curves are being used for the rotor blades over the cockpit. The angle of the rotor blades of a helicopter can be adjusted, and the tail rotor can raise and lower the speed to rotate the cockpit – in much the same way as the rudder on a plane. Tail rotor on a helicopter has also another function. If it wasn’t there, the cockpit would be spinning uncontrollably around itself. Most multi-copters avoid these kinds of mechanical problems by making rapid changes in the rotational speed of an even number of matched propellers. There are several ways in which they can be arranged (listed below) also called: tricopters, quadcopters, hexacopters, and octocopters.

 

⇒Read our article where the different type of copters is explained here⇐

The main advantage of having an even number of propellers is that their opposing rotation eliminates the torque which would otherwise make the vessel rotate around themselves.

propellerspropellerspropellersInstead of ensuring control over complex surfaces can multi-copters adjust the speed of the propellers to ensure momentum against the pilot’s desired direction. By reading out the slope through the built gyroscopes (gyros 6-axis) and the direction of the compass, the computer can ensure that the proper amount of power is applied to each rotor.

Directional control

As long as it is a computer that controls the drone, there is no reason to have a front or back. But to ensure a more natural pilot control (often due to the location of the camera) most multi-copters has marked the front of the drone. DJI Phantom uses red highlight stripes and colored LED lights.

Dji phantom
Hovering

You achieve stable hovering, by having the drone buoyancy directed straight down. Other things being equal the propellers must rotate at the same speed.

Rotation

A drone is rotatable around its own axis, while it hovers, by increasing the speed of the motors in the appropriate direction. In other words, the user can the turning control to the left or right.

Directional flight
drone flight

This is achieved by pressing the drone forward. To start the movement, the drone must lean in the same direction as you want it to fly, and keep this angle to ensure foreign directed momentum.

drone flight

Basics of drone flight

Despite what you might think from various troubling stories broadcast by the less rigorous part of the press, drones are pretty much flown the same way as model aircrafts that has been used for years without problems. Everything you need to master is the basic radio control. 

Pilot’s remote control

Some drones have a specially designed remote controls, but most use standardized radio control, making use of publicly available radio spectrum that draws up to 3.5 km. Remote controls (also called RC control units) consists of i.a. control sticks, switches and levers that can be configured to remotely control aircraft, cars and ships as well as drones.
Remote controls can vary in quality and functions, but some of the most basic things that a control must consist are:

Camera control

Drone controller

Some drones have motorized mounts. In these cases, there is a nob on the remote that enables you to be able to adjust the camera.

Mode button

This allows the pilot to select different automatic entered settings that come with the drone. For example, you can activate “GPS hovering” which ensures that the drone holds its position when you do not touch the control lever etc.

Control sticks

To control the drone and be able to fly it. Generally, the left stick is used to  gas up (take off), gas down (landing), rotate right and  rotate left. The right stick is used to ↑ move forward, move back, move to the right and move to the left.

Display

Some drones have a display on the remote control with various functions e.g. battery information.

 

 

 

 

How to build a drone 

If you want the ultimate flexibility in terms of design, the only right choice is to build your own drone. By selecting components and assemble them in airframes that you have picked yourself, you can create everything from a super fast stunt drone to a stable platform that can lift heavy things.

In order to build your own multi-copter, it requires that you choose components that can work together, connect them correctly and that you perform a number of necessary software installations before flying it for the first time. It sounds simple, but there is some complexity associated with the process. It requires some processing to ensure that the components work together. The installation can often cause some mess with computer software, and you should be able to figure out how to solder.

The gain from the extra effort, however, is that you are able to create something, you can be proud of. Also, you don’t have to spend all your money at once. You can for example start by building a simple airframe, and when you can afford it, you can add to the camera and later perhaps a sophisticated gimbal to stabilize the camera so that you can record video in high quality.

Other additions you can make later include the transmission of flight information to the ground or perhaps live video. You can also make changes to the remote control over time. Besides the advantage of the flexibility and the ability to spread the cost over time, self-building is a really fun way to acquire some practical knowledge – or a fun way to pass them on to a family member.

What do I need to build a drone? 

When you get the chance to fly something that you have built yourself, you will learn a lot about electricity and also develop your soldering skills, which is even more satisfying. A lot of different companies have spent time and energy on kits that contain all the component needed for building various drones. With a simple order, you’ll get everything you need. You can receive a box filled with boxes and also often with different instructions from different providers. But you should be sure that the components work together and that the engines and propellers have sufficient buoyancy without burning off. There is even often discount in terms of buying the component separately. Below are a few examples of some components you can buy and then build your own drone (Clicking the product picture to check prices and details out on Amazon):

Do you want to build your own drone and search for different components and tools? This link will help you to check the different options out.

Professional Drones

Assembled drones, built for commercial use, is a relatively new phenomenon. There is some confusion about the rules, but there are already several models in the market, and the selection only gets larger and better. 

The most obvious use of drones is for video recording and photography. The drones that are able to record are fairly expensive. Film makers expect a budget of at least $5,000 a day for the traditional helicopter footage. A professional team of drone pilots with a high-quality camera can work for about 2,000 dollars or less a day. Compared to prosumer models, professional drones has to lift far heavier equipment as photo lenses of high-quality consists of heavy glass components.

For such tasks, stability is more important than maneuverability. Many professionals like to work with additional security in the form of six rotor drones (hexacopter) or more, which makes it possible to carry out a relatively safe landing, even if some individual components has been broken.

Drones can be used to identify specific areas via GPS, which can be parts of a precise mapping of wide areas – from a construction place to a farm. Monitoring via the air is very useful in agriculture because it can help to inspect waste areas etc. Large UAVs as Microdrones MD4-3000 is intended for use by public authorities such as the police (to keep an eye on large gatherings), fire department (to identify where the fire is and to find people who are at risk) and commercial companies, including energy companies which may have hundreds of kilometers of cable that requires visual inspection.

However, there are many different drones in the market and as I previously mentioned it will only get larger as time passes. Below you can see some examples of professional drones:

DJI S1000+
DJI Inspire 1
DJI Phantom 4

Main Components Behind a Drone

All the parts it takes to fly a drone up in the air, and back again.

Frame

In aviation terminology, the airframe represents the mechanical structure of the vessel, except for its propulsion and technical systems. For drones, the airframe is the structure that supports all the other components. The most common type is the X-shape, which you often see in drones with four rotors (quadcopters) – but there are also other alternatives:

drone frame

Batteries

Battery technology based on Lithium-ion polymer (LiPo) has made it possible to create many new types of drones. The batteries are compact, relatively lightweight and able to contain a suprising amount of energy. However, they are not dangerous and must be treated with respect. You should know a bit about batteries before you start using them.

Motors

The drone engines must be extremely powerful as they must be able to perform about 8000 rpm and quickly change the speed. Since most drones consist of four rotors, there is no redundancy. The engines must be able to stay in the air, so it is important that they are reliable. You also have to keep in mind that each motor contributes to the overall weight of the drone.

The accepted standard is that the engines must be able to be capable of carrying twice the total weight of the drone – including components and batteries. If the engines can only carry the copter itself, it will be enough to get it to soar, but you also need extra force to rise and maneuver without it all burn.

Electronic Speed Control (ESC) 

To understand in detail how ESC work is not applicable when building a drone. However, it is important to select the appropriate ESC for the purpose. The unit reads the engine’s speed and ensures that the engines achieve the intended speed by adding the necessary power. Learn More 

Propellers 

Choosing the right engine is only part of the equation. You must also choose which propellers, the engines should drive, so you know how much lift is being created. A propeller is sold in all kinds of materials, each of which affects their efficiency – the most important parameters are the size and angle.

Fly controlDJI naza

The Fly Control Unit simply represents the ‘brain’ of the multi-copter. It is the central mid-point, wherein the information from the drones height and position sensors along with commands from the remote control are received and from which instructions are sent to the motors.

Remote control

Traditional radio control is the core of most ‘pilot drone’ interactions. Some drones use of wireless devices – such as the Parrot drones – others use automatic flight. There are many options on the market.

Telemetry

Just as it is possible to receive video (either live or by recording it) from the drone. It is also possible to receive many other forms of data such as battery status, altitude, direction, etc. Generally, this kind of information is called telemetry. If you utilize telemetry, it can change the way you fly.

Landing equipment

Traditional aircraft pull their landing gear up to promote a more aerodynamic shape, as it provides rapid, more efficient and softer flights. Helicopters don’t get the same advantage of this, so many landing gears are often relatively simple. However, retractable landing systems have become more popular with photographers.
DJI’s popular Inspire 1 has a built-in system that automatically can lower the landing gear when it falls below a certain point. When the drone fly, the legs go up and allows you to shoot in 360 degrees.

Specifications to be considered (before buying a drone)

When considerering specifications involving each drone, there is a lot to consider. It is difficult to completely decide which drone will fit best with each person due to the amount of features provided. This post is for informational purposes only, so you know what...
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