How to choose drone parts for DIY drone?
If you have technology and a limited budget, then DIY a drone yourself. DIY drones must know how to choose motors, ESCs, propellers, ESCs, batteries, and racks. The following is help you to know how to choose these drone accessories.
Motor KV value: - large KV with small propeller, small KV with large propeller
The KV value is the idling speed of the motor per minute per 1V voltage, such as KV1450, the idling speed is 1450 rpm under 1V voltage. Under the voltage of 10V, the idle speed is 14500 rpm.
If the number of winding turns is large, the KV value is low, the maximum output current is small, but the torque is large; the number of winding turns is small, the KV value is high, the maximum output current is large, but the torque is small.
The smaller the KV value, the higher the efficiency. Aerial photography should use low KV motor with large propeller, low speed, high efficiency, and also low vibration of low-speed motor. These are extremely beneficial for aerial photography.
Motor model: - The stator is thick and powerful.
Motor model, such as 2212, 3508, 4010, these numbers indicate the diameter and height of the motor stator (as shown below). The first two digits are the diameter of the stator, and the last two digits are the height of the stator, in millimeters. The larger the first two digits, the fatter the motor, and the larger the last two digits, the higher the motor. The big and tall motor is called Gao Fushuai. Powerful, efficient and expensive!
Motor efficiency: —— 3~5A, high efficiency
Efficiency is marked as follows: g/W (grams per watt) motor power and pulling force are not proportional, that is to say, when 50W is used, the pulling force is 450g, and when 100W is used, it is not 900g, but may only be 700g. The specific efficiency depends on the efficiency table of the motor. Most motors are most efficient at currents ranging from 3A to 5A. Generally, during normal flight, the efficiency is kept within a reasonable range, and the endurance can be well guaranteed.
Experience : The weight of the whole machine should be less than 2/5 of the maximum lift of the motor
Many beginners who play aerial photography will choose the 2212 motor, why? Most novice tutorials talk about the 2212 motor. For entry-level players, the 2212 motor can indeed. But for aerial photography, 2212 is obviously not enough. If the weight of the four-axis exceeds 1.5 kg, the 2212 motor cannot be selected for this motor. But most entry-level aerial photography drones have a weight range of 1.5~2KG.
In addition to lifting itself up, the lift of the four-axis drone also uses part of the force to move forward and backward, and roll left and right. The most important thing is wind resistance. It is recommended to reserve three-fifths of the lift for these actions and wind resistance. For example, the four maximum pulling forces of the 2212 motor are 3320 grams, and the weight of the whole machine should not exceed two-fifths of the maximum pulling force, which is 1328 grams. If this limit is exceeded, the motor is running at a high load, the efficiency of the drone becomes lower, the motor vibration becomes larger, and the flight is unstable, which can easily cause a crash.
Experience 2: Do not choose a motor without parameters
Four-axis drones basically use external rotor motors. Inside the coil is the stator. Motors are very important for aerial photography! ! ! Be sure to buy a brand of motor, the quality is guaranteed. All brands of motors have full efficiency tables and full throttle temperatures.
The benchmark for aerial photography ESCs is the Hobbywing Platinum 30A ESCs. It is loved by players for its fast response and delicate throttle feel. Not too expensive.
3. The propeller
Specifications and Models: Propeller specifications, generally represented by 4 digits, the first two digits represent the diameter, and the last two digits represent the pitch. Take the 1060 paddle as an example, 10 means the diameter of the paddle is 10 inches, and 60 means the paddle angle (pitch, 6.0 inches, or 152.4mm).
The propeller is an important accessory of the drone, and it is also an accessory that is easily damaged. Aerial photography requires stability and efficiency. It is recommended to choose APC, which has high efficiency. For heavy loads, carbon fiber propellers can be selected. If the load is very large, you can choose beech paddles, which are not easy to deform.
The same motor, different KV value, different propellers, each motor will have a recommended propeller. Relatively speaking, if the propeller is too small, it cannot exert the maximum thrust; if the propeller is too large, the motor will overheat, which will demagnetize the motor, resulting in a permanent decrease in the performance of the motor.
Recommendations for four-axis aerial photography drone motor propellers:
For drones weighing less than 1.8KG, 2216KV800 motors can be used with APC1147 propellers.
For drones weighing less than 2KG, 2810KV750 motors can be used with APC1238 propellers.
For drones weighing less than 2.5KG, 2814KV700 motors can be used with APC1340 propellers.
4S batteries for drones weighing less than 2.5KG
2814KV600 motor with APC1340 propeller;
3110KV650 motor with APC1238 propeller;
3508KV580/KV700 motor with DJI1555/APC1540 propeller;
4108KV480/KV600 motor with APC1447/APC1540 propeller.
6S batteries are available for drones weighing less than 3KG
3508KV380 motor with DJI1555 propeller;
4108KV380 motor with DJI1555 propeller;
4008KV400 motor with APC1447 propeller.
5200mAh, which means that it can be discharged for 1 hour at a current of 5.2A. Of course, we just understand it that way. The actual discharge time needs to refer to the relevant technical parameters provided by the battery manufacturer.
30C battery refers to the discharge capacity of the battery. For a 30C battery, the maximum continuous discharge current is: battery capacity X discharge C. For example: 5200MA, 30C battery, the maximum continuous current is =5.2X30=156A (Ampere). If the battery is operated at a current of 156 amps or more for a long time, the battery life will be shortened. For the single-chip voltage of the battery, it should be 4.15-4.20 when fully charged (3S battery corresponds to 12.6V), and the minimum voltage after use is more than 3.7 single-chip (3S corresponds to 11.1V, remember not to over-discharge), do not use for a long time The best storage voltage is 3.9 (3S to 11.7V).
Select the battery capacity according to the weight of the aircraft. If it is too large, the flight efficiency will be low, and the battery life will be short if it is too small. It is recommended to use a 3S battery alone for the gimbal and image transmission, and 2200MAH15C is sufficient.
5. How to choose a drone frame
The machine below 2kg can choose the glass fiber frame; the machine above 2kg decisively choose 3K carbon fiber drone frame.
The formula for selecting a rack is as follows:
Rack wheelbase = (size of propellers*25.4/0.8/root number 2)*2
Here are some suggestions for blade and wheelbase combinations:
10-inch propeller with wheelbase 450MM rack;
11-inch propeller with wheelbase 500MM rack;
12-inch propeller with wheelbase 550MM rack;
13-inch propeller with wheelbase 600MM rack;
14-inch propeller with wheelbase 650MM rack;
15-inch propeller with wheelbase 680MM rack;
16-inch propeller with wheelbase 720MM rack;
17-inch propeller with wheelbase 780MM frame;
18-inch propeller with wheelbase 820MM rack;
19-inch propeller with wheelbase 860MM frame;
20-inch propeller with wheelbase 900MM rack.
Balance of the drone
The high center of gravity of the high tripod is poor in balance, and there is no problem during take-off and flight. If the center of gravity deviates greatly when landing, it is easy to roll over when landing. If the center of gravity deviates greatly, adjust the height of the tripod and the installation position of the battery.