Making A Quadcopter in Nepal for beginners

Introduction:

This tutorial will be for absolute beginners or beginners with very little knowledge in this field. All we will be doing for our first part will be understand in the physics and concept of building a quad.

What is a quad copter?

A UAV (Unmanned aerial vehicle) with four propellers for flight is called a quad copter. Don't get confused with drones and quads. Drones are any UAV that are fully or partially automatics. Number of moving parts or propellers is not fixed while in quad there must be four and can be automatic. Also there are other copters like bicopter, hexacopter etc named after the number of propeller they use. And one thing, that a quad copter has two configuration "X" and "+" that we will be talking later.

Requirements:

Now to make our quad a moving object we are going to need following things:

1.  Frame: Everyone can guess this one. You will need a frame or body in which every other object will be mounted.
2. Motors: We will be using Brushless DC motors. These are going to make our beast movable.
3. Props: Mounted on motors these 4 props are going to lift our beast from the ground.
4. ESCs: Electronic speed controllers (ESCs), as the name suggest are going to control our motors’ speed.
5. Flight control board: Every electronic need a brain and this one is ours. It is going to do all the mathematics and physics required to make our beast fly and will send the result to motor through ESCs.
6. There are other sensors and units that can be used to make your quad really fancy and that we will discuss later.

How does it fly?

First let's know what happens in the quad before we build it. 

Fig: flight of quad

There are four propellers (motors), two moving clockwise while other two anti-clockwise. As you can see in the picture motors 1 and 3 rotate in clock wise and motor 2 and 4 rotate in counter clock wise direction. Now let’s see, when the speed of the motor 1 and 4 decreases but the speed of 2 and 3 increases then the quad will be pushed left and vice versa for right.This movement is called “roll”. Just like that for forward, speed of 1 and 2 increases and of 4 and 3 decreases. This is called “pitch”. And if the speed of 1 decreases and 2 increases, other remaining same the quad turns left. Such movement is called “yaw”. Finally increasing the speed of all motor lifts the quad up and vice versa. This is called “throttle”.

What to know?

You must never test your quad with propeller attached. Take off those props while checking your beast. Also never ever fly your quad where there is crowd. Because these are machines and deadly machine, anything might go wrong and you might end up in jail or hospital. Finally don’t over charge your battery. If not handled carefully you might get into serious trouble as Li-Po battery can turn into bombs if overcharged.