7/8.6mm Coreless Motor Gearbox, Module 0.3 Gears, Reduction Ratio 9:36 Use two 681X ball bearings with cage!！Output shaft 1.5mm. Note that it is suitable for 8.6mm motors, and the use of 8520 coreless motor will be looser, and if you want to use it, you can only fix it with 704 glue. To fit the two bearings, the motor shaft is actually 1.48mm. The propeller adapter for the 1.5mm shaft is also not included.

Note: needs to be assembled gearbox by yourself.

The weight of the 720 coreless motor gearbox is 4.68g

The weight of the 8620 coreless motor gearbox is 6.02g

Although it is suitable for 8.6mm coreless motor, I found that the coreless motor of 8523 is barely usable, but the weight is very heavy, 7.2g

8620 and 8523 coreless motor

7mm gearbox without coreless motor

7mm gearbox with 720 coreless motor

8.6mm gearbox without coreless motor，9 teeth nylon pinion for 1.0mm shaft

8.6mm gearbox without coreless motor，9 teeth nylon pinion for 1.2mm shaft

8.6mm gearbox with 8620 coreless motor

The custom-made motor shaft is actually 1.48mm and 30mm in length. In order to fit the two 681X ball bearings, a circlip is required for the tail section.

Assemble the circlip

Install 36 teeth gear

The top of the gearbox frame

The bottom of the gearbox frame

There are 4 bulges  inside the gearbox frame

The motor is not all close to the gear frame, which is more conducive to the heat dissipation of the motor

Install the 1.5mm propeller adapter

Install the propeller

GWS 5030 and 6030 propellers were used for testing

The test of the 720 coreless motor gearbox with GNB 550mah, 4.35V battery and 5030 propeller

The battery full charge indicator is 4.5V

The motor is directly connected to the battery, the voltage drops to 3.2V, the working current is 0.93A, and the thrust is about 30g

720 coreless motor gearbox with 6030 propeller

The motor is directly connected to the battery, the voltage drops to 3.0V, the working current is 0.97A, and the thrust is about 31.45g

8620 coreless motor gearbox with 6030 propeller

The motor is directly connected to the battery, the voltage drops to 3.4V, the current is 0.88A, and the thrust is about 32.89g

8523 coreless motor gearbox with 6030 propeller

The motor is directly connected to the battery, the voltage drops to 3.2V, the current is 0.91A, and the thrust is about 33.48g

Conclusion: Now with voltmeter and ammeter, and 4.35V Lipo battery to simulate the real use situation, the battery is directly connected to the motor test, the voltage drop is very large, directly down to about 3.2V, the current is about 1A, and the thrust is only about 30g. IIn the past, I used the adjustable power supply to test the thrust data, through the comparison with the direct use of the battery test, now I know that the adjustable power supply voltage is set to 3.9V-4.2V test data is more impossible, and even the 3.7V test data can not be reached, the data of about 3V is true and reliable, of course, the motor of our store may not be good. You can test with your own good motor, but it is better to test with a battery, even with an adjustable voltage, it is recommended to test with 3V.