RC drone Elementary Knowledge

Multicopter basic knowledge

Multicopter is a special copter with more than three motors. It has six modules, include flying platform, flight control system, propulsion system, remote controller, remote control receiver, PTZ camera.

1. Flying Platform

The size of flying platform is depend on size of oar wing and volume of motor; oar wing longer, larger motor, and then the platform will be increased accordingly. The platform is mainly use light material to reduce drone payload.

2. Flight control system

Flight controller usually contains built-in sensor such as controller, gyroscope, accelerometer and barometric. The drone is depend on this sensor to stability of body, and then cooperate with GPS and barometric to locking at the specified position and height.

3. Propulsion System

Drone propulsion system includes the oar wing and motor composition. When oar wing rotation, it can produce air flow forces to lead drone body flight. The propulsion built-in electronic speed control system then adjusts speed of motor.

4. Remote Controller

Pilots control the drone through remote controls.

5. Remote control receiver

Main function is to make the aircraft received by the remote control signal from remote control commands.

6. PTZ camera

Nowadays some manufacturers allow user to mount a third party drone camera, such as GoPro Hero 4 and Canon EOS 5D series. Recently some manufacturers have also adapted the M4/3 system for aerial shooting (such as Panasonic LUMIX GH4) Cameras are normally installed on the Gimbal on the aircraft. Gimbal is the most important part in aerial system. It can make shooting pictures more stable.

In addition to six modules above, players can also match their favorite FPV glasses, let experience the feeling of immersive.

What parts need to prepare for DIY quadcopter?

1. Brushless Motor (4 pcs)

2. Electronic Speed Controller (Abbreviation: ESC, 4 pcs. Common brands have Hobbywing, Tatttu, Little Bee T-motor etc.)

3. Propeller (4 pcs)

4. Flight controller (The common brands have KK, FF,ADUINO Open pilot etc.)

5. Battery (11.1v RC lipo battery)

6. Remote control

7. Flying Platform (Not a choice)

8. Charger (Try to choose balance charger)

Ⅰ. Flight controller and remote control

1.Usage of flight controller

The flight controller is control gyroscope, to rapid adjustment of quadcopter condition. If there is no flight controller, quadcopter will not be able to flight due to flight power imbalance. So flight controller is one of most important parts of a drone.

2.What is X mode and + mode?

 flight modes

Above is the different between X mode and + mode, compare with them X mode is harder to fly, but more flexible. + mode is easy to fly, but flexible almost, so it befit for the newbie. Pay special attention to, X mode and + mode have different flight controller installation. If the flight controller is installed the wrong way, the drone will violent shaking and can't fly.

How high can I fly my RC airplanes?

It depends on the type, the material and the power system of your airplane. Each relates to the other. Normally you will be able to fly it up to 1000 meters high.

How far can I fly?

It depends on two factors: Your plane's energy source and the operation range of your controller. Normally it ranges up to 2000 meters. But in most case you will only fly them within 500 meters radius in order to see the move clearly.

Material of the airplane

The airplane is normally formed of the frame body and power electronic equipments. Materials of the frame include foam, plastics, metal, carbon fiber, nylon, wood, Fiberglass and so on. In order to reduce the body weight, foam and carbon fiber, light wood and empty inner or KT broad and carbon fiber are normally seem as materials combination for frame body. As seem similar in kites.

Taking off and the wind direction?

Fixed wings normally take off against the wind. While small airplanes are suggested stop flying in moderate breeze or stronger wind, due to the weak ability in wind proof.

What's a naked plane?

A naked plane refers to a plane that only has body frame, not including any electronic compartments.

What does PNP version mean?

A Plug-N-Play electric RC airplane has the motor, ESC and a servo installed but is missing the transmitter, receiver and motor battery pack (& charger). You will need to supply your own transmitter, receiver and battery pack.

What does RTF version mean?

RTF stands for ready to fly. When you buy an RTF RC plane everything comes with it in the purchase, including the radio control gear to fly it. Most of the RTF airplanes come with only very basic configurations.

Pros & Cons in Electronic powered and oil powered?

Early age UAV was powered by methanol or petrol due to the low energy density of batteries and inefficiency of brushed motors. As development of Li-ion batteries and the brushless motors, electronic powered UAVs are now as good as methanol or petrol powered UAVs, plus the electronic UAVs are more easy to fly and maintenance. Electronic UAVs requires brushless motors, extra Li-ion batteries and chargers as power source, these are recommended for newbie.

What is a simulator?

A simulator is a piece of software that simulates the environment in actual UAV flying situations. So that the pilot can practice the basic operations in flying a UAV such as controlling of the accelerator, direction control and movement control. Simulator software that are normally used includes phoenix RC, Real fight G4, Reflex XTR, Flying Model Simulation etc.

How to operate a UAV?

You normally operate a UAV with a remote control. Signals will be sent out by trigging the Rocker on your remote control. UAV then will do the corresponding action according to your operation.

What is a remote and receiver?

A device on UAV to receive the signal you send with a remote control on the ground is called the receiver. Remote and receiver are communicating with 2.4GHz radio wave.

Differences between Japanese controller and US controller

UAV hobby are widespread from Japan and North America in the early age. Definitions of the function button on the controller are different from then on. For example, in Japanese version: we use the left stick to control up down and left right. We use right stick to control accelerate and aileron. In the U.S version it's vise versa. Normally most UAV controllers are in Japanese version and RC Helis controllers are in U.S version.

Ⅱ. ESC and Motor

 Tattu ESC

Why do we need ESC?

The role of the ESC is to transform the signal of flight control board into the size of the current to control the motor Revolutions (RMP). Because the motor current is very high, when motor normal work, there is the average current of about 3amps, if there is no ESC, the flight control board simply can not afford such a high current (and also it without the function of driving brushless motor). At the same time in the four-axis, ESC also acts as a voltage changer, change 11.1v voltage into 5v to supply power for the flight control board and remote control.

Buy high current ESC or low current one?

ESC will be marked with the number of 'A', such as '20A', '40A', which mean the current that ESC can provide. ESC of high current can be compatible with low current things. Conversely, low current of ESC can not be used for high current.

The specification of ESC

The 'A' in ESC is the unit to measure how much current can the ESC constantly outputs, such as 60A, that is, the maximum constantly output current is 60A. Please do not discharge the current over the 'A' on ESC, otherwise the ESC will burned.

What is quadcopter ESC?

There are fast response and slow response in ESC, and in quadcopter flying, the ESC need to response quickly, so quadcopter usually this fast response one, which called quadcopter ESC. In fact, most ESC can be programmed, can be programmed to set the response speed. So in fact there is no exclusive one to say.

What is the meaning of ESC programming?

First of all to explain that ESC own a lot of functional mode, select this function is to program the ESC. The programming path can be used to connect the ESC to the throttle output channel of the remote receiver (usually 3 channels), according to the instructions, in the remote control by moving the rocker to set, this method is more trouble, but economic. In addition, you can also through the manufacturer's programming card to set (need to buy separately), the method is simple, no need to access the remote control. Make sure that consistent settings of purchased ESC, otherwise it's difficult to control it. For example, if ESC start mode is not the same, then some are very fast, and some are still very slow, there's something wrong with it. To set the ESC through the remote control, keep in mind that ESC is connected to the motor, and you'll hear the dripping sound, that is, you're right. and if there's no sound, that mean you didn't connect to your motor.

The brand of motor

Align, scorpion, T-motor in common use, and align, scorpion most use in heli.

About Motor model

Motor model, each manufacturer has its own number of rules, mainly for KV value, that is, motor code. take 2216 for example, '22' is the diameter of a motor. '16' is the length of motor. Compared to 2212, 2216 is more powerful than 2212.

What is the meaning of KV value?

KV value, it means every additional voltage, and revolutions of motor (RMP) increase how much. For example, KV 2000 means when the voltage is at 10, and motor turns 20000 times. The meaning of this parameter is: to help you determine the performance of the motor, motor of high KV is violent, small internal resistance, high current, high power, fast speed. Or the same voltage out of the power has a very good limit of revolutions, but it's restricted by the motor's own design and material, there will be a power cap, generally said that high KV match with a small high-speed propeller, low KV match with large propeller, this is similar to driving car.

Ⅲ. Propeller

The Model of Propeller

Similar to motor, the model of propeller also has four number, like 1040, 7040, the previous two numbers mean its diameter (inch) and the behind two numbers mean its angle.

What is positive and negative propeller and why they are needed.

In order to offset the propeller spin of quadcopter, the direction of rotation of Separated propeller is different. This why positive and negative propeller are needed. But their winds are both blown down. The positive propeller is suitable for clockwise rotation, but the negative propeller, on the contrary. When installing, remember put the side with words upturned regardless of positive and negative propeller. (The propeller's fruity side is the same with the direction of motor rotation.)

The installation direction of the propeller

Generally, put the side with printed specifications on the propeller (6*4) forward. You could simply feel the wind, and the wind of propeller is always from head to tail. At the same time, pay attention to the motor steering is normal. If reverse, just exchange the three wires on the motor at random.

The collocation of motor and propeller

This is a very complicated problem, though theory can be described. The greater the propeller, the greater the lift, which means more power needed to drive; the higher propeller speed, the greater the lift; the smaller the KV of the motor, the greater the rotational power. To sum up, big propeller needs to use low KV motor, and small propeller requires high KV motor (because the speed has to be used to make up for a lack of lift). If High KV with big propeller, the power will be not enough and it will be difficult to drive. In this case, it still rotates a low speed and motor and ESC will be easy to burned. If low KV with small propeller, it will be no problem. But the lift power will be not enough and it cannot take off, eg: 1000kv motor with about 10 inches propeller.

Ⅳ. Steering Engine

Analog Servo and Digital Servo

Digital Proportional Servo is a better Servo type of Analog Servo. If without MCU microcontroller in the Electronic circuits, it is commonly called Analog Servo, while for the Digital Servo, it is with MCU microcontroller in the Electronic circuits. Digital Servo has faster response speed, smaller no reaction zone, high location accuracy and stronger anti-interference ability. The fixed wing foam Airplane which needs not so high precision response, like Surfers and Cessna, could use Analog Servo. But for helicopters, whose inclined plate Servo and lock tail Servo need high response speed and location accuracy, Digital Servo will be needed.

The function of Servo

Servo can be understood the motor with precise control, which divides into Analog Servo and Digital Servo. Its function is used to perform specific rudder surface changing and change flow, make we input in the actual movement of parts. It is just like when we need to change the direction a boat sailing, we will operate the rudder, so as to let the water change, and then let the boat change direction. When choosing servo, according to the rudder surface request of the airplane to decide its Torsion size, response speed, weight, size, etc. Because when the airplane fly with high speed, rudder surface will be affected by the strength of wind resistance, so you should choose different servo. Usually the servo strength is measured by torque, the unit is oz/inches or kg/cm. Torsion means in setting range, how much rotating force it can make. For?example, the 1.6 kg/cm servo can pull 1.6kg thing in 1 cm distance. The farther away from the axis, the smaller torque. In 2 cm distance, it can only pull 0.8 kg thing. Another servo related quantity is servo speed, which means the time for servo turning 60 degrees (0.01 s / 60°)

Why Digital Servo has higher speed?

Either analog or digital Servo, at constant load torque, motor speed depends on the size of the drive signal on duty cycle and has nothing to do with the frequency. Digital servo can accept higher frequency PWM external control signal, and get the location information in a shorter period of time and adjust Servo radial position. The reaction speed of Digital Servo is higher than Analog Servo, rather than motor speed.

Why make a squeaking noise after Servo gets powered?

Servo always makes a squeaking noise to adjust sound by back and forth locating, because some servos have no hysteresis control function and if no hysteresis control dead zone range is small, as long as the input and feedback signals fluctuate, and the difference is beyond its dead zone control, servo will send signal to drive motor. But with no hysteresis regulating function, if the mechanical precision of servo gear is poor, with big gear phantom, will drive the rotation of feedback resistor, and the range is beyond dead zone control, then the servo will adjust and make a squeaking noise all the time.

Ⅴ. The battery knowledge

What are the parameters of UAV battery?

The parameters of UAV battery have voltage, discharge rate, capacity and internal resistance etc. For example: 3s 2200mah 25c 5c-charge battery. 3s stand for 3 cell batteries in series, a single cell voltage is 3.7v, so this battery voltage is 11.1v, the capacity is 2200ma, 25C discharge stand for the battery can reach 25c*2200ma=55A Maximum current discharge. 5c-charge stand for battery can reach 5c*2200ma=11A Maximum current charging. Common battery brands have: Gens Ace, Tattu, Hobbyking etc.

What is the voltage of RC battery storage?

Due to character of UAV batteries, usually full charged few hours before the batteries are being used will be recommended. When the batteries are not in used, please store them at voltage from 3.8v - 3.9v. Over charge or discharge would affect the battery performance. The right way to storage can extend batteries' lifetime and maintain them in certain capacity.