Hello steemians, hope you guys are having a wonderful day out there, trust me I am having a good one. I am sure you all know what a drone is, how it looks like and things it can do but do you know some of the basic components used for designing one and how its hover and flight mode is achieved.

Helicarrier in the movies " Avenger series (winter soldier) and Edge of Tomorrow" has inspired me to learn about this aircraft and I will be using the post to share with you some of the things I have learnt about it and if truly it is capable of carrying humans and bucky loads as shown in the movies. I hope you enjoy it and learn one or two things from it.
_{pixabay: quadrocopter}

There are different types of drones in the world today, ranging from their sizes, abilities, aerial platform and range (distance from the user). Before the advent of drone, capturing of an aerial image or video was a difficult task to accomplish. One would require a long ladder or probably rented a helicopter to carry out such task which of course is very strenuous and costly. But with the help of this aircraft, this task has being done with ease, great precision and cheaply with lower risk and liability. Filmmaking industry make use of this aircraft to take capture aerial view action or footage at a convenient angle of their desire.

Drone has also found its useful in the agricultural sector as well. Sensors like heat sensor can be installed on the aircraft to detect the temperature of the livestock, presence of water and for emergency responses (incase someone got injured in a remote part of the farm). The type of drone used in performing some these tasks is known as the quadcopter (quadrocopter).

A quadcopter drone, one of the most popular drone in the market, is a unmanned aircraft which makes use of its four rotors to lift and propel itself into and through the air. The four rotor blades are configured mainly in two ways namely; plus and cross configuration. The pair of rotor blades that are connected diametrically rotates in the same direction while the other pair rotate in the other direction (clockwise and anti-clockwise).

Country like the United State of America has legislate the use of drone for package delivery, photography and so on. Also in East Africa, Rwandan government make use drone to transport vaccines and medicines, and retrieve medical samples in and out of a remote part of the country.

_{pixabay: quadrocopter}

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Fundamental components of a quadcopter

Looking at the entire system as a whole is a bit complex to understand how its performs some of its functions but having a detailed knowledge on some of the components used, makes it easier to understand. List and explained below are some of the components used for designing a quadcopter.

• Frame

  Also known as the body is responsible for holding all other components in place. They are often built with materials such aluminium, steel, carbon fibre, plastic and fibre glass. Recent designed quadcopter make use of carbon fibre because of its light weight and structural stiffness properties.

• Motors and Propellers

  
  
  ^{pixabay: A drone propeller attach to the motor}
  Motors are devices capable of converting electrical energy supplied by the power source into a rotational energy (mechanical) to turn the propellers attach to them. The most common type of motor employed for the design is a brushless type with each motor design to operate at variable speed via the Electronic Speed Controller. Propellers are blade-like device that turn on the shaft to provide a push against air in the weight of the aircraft.

• Electronic Speed Controller (ESC)

  ESC controls the rate at which the motors rotate. One ESC is assign to one motor making the total of four ESCs in a quadcopter. These controllers are partly connected directly to the power source and also to the flight controller within the craft body. Within its circuit board is a voltage regulator known as the which is responsible for supplying constant voltage to other component like flight controller.

• Flight Controller (FC)

  This controller is both the heart and the mind of the aircraft because its controls the interface between the software and the hardware part of the ESCs. Input from the receiver are taking the FC to calibrate the motor RPM as desired via ESCs. FC also holds additional sensors to improve control and balance the quadcopter. Read more on the sensors and their roles here

• Transmitter and Reciever

  Quadcopter transmitters are like joysticks used for playing video games but in this case, they are used to control the aircraft. They are usually designed with a minimum of four channels to pilot the aircraft. The channels includes throttle, yaw, pitch and roll which will be explained in detail later in this post. A standard flight controller recommend 8 channels. Operating any channel on the transmitter will send a signal to the Reciever installed within the drone to instruct the FC to calibrate the motor speed.

• Batteries

  The power source used for powering the aircraft is a battery which of course must be rechargeable. The most common type of battery used in powering the aircraft is the lithium polymer (LiPo) because of its expansive limit. Learn more about UAV batteries here

_{Connection squence between components showing the direction of power flow Image source: Me}

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How quadcopter hover and fly

Before explaining how this aircraft hover and fly about, it is necessary to understand some of the forces that acts on it. This forces includes drag, thrust and lift.

Drag: This is a mechanical force that opposes the motion of an object through any medium. Since the medium here is air, it is called aerodynamics drag. This force is generated by the difference in the velocity of the aircraft and the air. Note that drag is only active when the quadcopter is in motion.

Thrust: This force is necessary to overcome the force drag. The propeller produces the thrust force responsible for the movement of the aircraft in air.

Lift: Newton's third law for motion (every action has an equal but opposite reaction) can be used to explain how lift is generated in the propellers. The pushing of the air downward generates a lift and ones the force is greater than the weight of the quadcopter, it will float in the air.
_{pixabay:Man flying a drone}

For the quadcopter to fly and hover around, the following condition must be met:

• The direction of the rotation of each motor must counteract the torque produce by the motor placed opposite of it in order to prevent the craft from spinning as a result of their torque effect ( torque produces by motor A is cancelled out by the torque produced by motor B, likewise C cancel out D).
• The speed of the motors must all be the same.
• The quadcopter must generate a rotational speed sufficient enough to produce a lift force to overcome its own weight.

The operation of the transmitter channels stated before (throttle, yaw, pitch and roll) determine how the motors interact with each other and rotate to make the quadcopter fly as desired.
_{Quadcopter X-configuration image source: wikimedia commons;Creative Commons Attribute-Share Alike 3.0 Unported license}

• Throttle: Gaining and losing altitude is determined by the rate of speed at which the motor rotates and this action is controlled by the throttle channel on the transmitter. Increasing the rotational speed of all the motors at the same time cause the aircraft to gain altitude and vice verse.

• Pitch: This channel instructs the quadcopter either to move forward or backward. To move forward, the rotational speed of the two rear motors (C&D)must be greater than the front motor motor and also to move backward, the front motor rotational speed must be greater than the motor at the back.

• Roll: Unlike pitch, the roll is responsible for side movement and this is achieved by increasing the speed of the two motors (A&D) at the left side of the quadcopter to move it to the right and vice versa

• Yaw: The rotational movement of the quadcopter about its axis is made possible by the yaw control. The speed of the pair motors that are diametrically opposing each other (A&C or B&D) are increased and decreased to achieve the quadcopter rotation. Since the motors parallel to each other are rotating in the same direction, variation of the torque in the direction of the pair of motors with the higher rotation causes the aircraft to rotate in the direction of the increased torque.

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Application of quadcopter

Photography

Recent development in the field of photography for the last couple of years is drones with quality cameras. This UAC has made capturing of unique viewpoints of common subjects like landscapes, settlements, events etc less expensive and interesting.

Research

Quadcopters are useful tool for reseachers to test and evaluate new ideas in various other fields like navigation, real time system, robotic and flight control theory.

Military and law enforcement

Drones are use by military and force personel to conduct search and rescue mission, surveillance and reconnaissance.

Drone can also finding its functions useful in fields like agricultural sector, journalism, delivery system, sport, art, film making, oil and minerals exploration, disaster relief and so on.

Disadvantages

Technology has brought about both positive and negative effect on the society. The following are some of the shortcomings and setbacks on the society:

• It can be used evade to peoples privacy by criminal element to perform their criminal intention.
• The main control system of the drone can be hacked by hackers whose intention is to obtain vital and useful information from the system without the owner's consent
• They have short life span because of the size of its batteries design.

Conclusion

Quadcopter belong the class of helicopter but unlike convectional helicopter with two rotors, it possess four rotors with great maneuverability and agility. They are very cheaper and durable compare to convectional helicopter at a small size.

Advent of this unmanned aircraft in the world today, have being of a great assist in the performance of human tasks. Areas like photography and journalism have been seen to patronize its purposes and efficiency when capturing images and videos. It has also minimize casualties among military personnel when performing operation like search and rescue, surveillance and so on.

But trying to make them Manned Aerial Vehicle (MAV) like helicopter, airplane and the likes, has been difficult because of its stability which is difficult to maintain without the aid of a complex software system. Also increasing the blade size increases its momentum causing a delay in the changing of the blade speed which has a negative effect on the control.

With all this said, making Quadcopter a MAV may be impractical unlike what I have watched in the movies but I hope with further research and advancement, a quadcopter can be made to carry humans and heavy payloads like other aerial vehicles

References

How drone works and fly
Quadcopter control system
Can quadcopter carry humans and replace helicopter
Advantages and disadvantage of drone technology
Drone delivery
Types of drones
Uses of drones

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