The drone can fly vertically, horizontally and diagonally all with 4 motors In addition, you can make some acrobatic movements. In this lesson, we will examine how the drone is controlled to fly in the mentioned ways. Drones use direct propulsion from propellers to push them up into the air So that the thrust must be higher than the weight and drag This is called by Thrust to Weight Ratio Where the least must be one or 1.5-2 (Recommended). Each drone propeller pushes the air down to generate lift So to raise the drone up all you have to do is open the throttle gradually. But what next? How is the move?
Well, there are 3 kinds of movements for vertical flight:
- Hover – It is the process of increasing the speed of the motors to generate a thrust equal to that of gravity so that the Drone is able to take off Here the Thrust to Weight Ratio is around 1.
- Climb and Descend – They are intended to take off and land So the drone begins to fly when increase the throttle opening to increase the speed of the motors here the Thrust to Weight Ratio becomes greater than 1 to land, we close the throttle gradually.
But how will the four propellers rotate?
To fly the drone, the two top propellers must move clockwise and counterclockwise, This applies to the two propellers lower, so that all propellers must be the same speed to have unique Hover and Climb, and to keep the speed constant for all propellers we use ESC. That’s all about drone vertical flying, but how do we move forward, backward, left and right? We will use the Turning orientation theory.
Now we will study how to control the direction of the drone with different angles. We know from physics that when one fans rotate counterclockwise and another fans clockwise In this case, the angular momentum is zero. If all the fans move opposite for each other , the momentum will be zero and we will keep the drone flight stable.
If you want to move the drone in any direction, you will change the fan speed For example, if we want to move the drone forward, we increase the thrust of the upper fans and less thrust or same speed for lower fans.
The method of calculating the thrust force of the motors is simple, we use in the drone motors called Brushless DC Motor These motors are characterized by high rotational speed (RPM). For example, our motors of thrust is 1500 grams And we want to build a quadrant Dorne first calculate the total weight that can be lifted by the four motors:
Total Lift = Number of Motors * Thrust Force
So in our case Total Lift = 1500 g * 4 = 6000 g Which represents the maximum load that can be lifted which includes the total weight (frame, motors, lipo-battery and electronic equipment). But to make the drone fast and maintain a longer flight time, we take a safety factor by dividing the total thrust by 1.5 or 2 to be 6000/2 = 3000g the best choice. So simply fly a drone but we use ESC to control the motors to take the desired direction.