One of the aspects of this project that I was a bit concerned about—among many other such aspects, but especially this one—was whether the brushless motors would actually function underwater without shorting out. Although all I would see online were claims that brushless motors are completely fine underwater due to the coatings on the copper windings and such, I just had to test it myself for my own sanity.

So I went ahead and purchased a couple of the components I would need for the drone and for testing. Here’s a list of the things I got:

• 4x DYS X2812 900KV brushless motors (it comes in a pack of 4)

• 4x Readytosky 40A ESCs

• Servo Tester

• 6V battery pack with a female 3 pin JST connector

• 16 AWG wire

• Deans connectors and bullet connectors

I also printed out a quick motor mount so I could hold it safely while it runs and also found a voltage source. I started assembling the circuit by first crimping the bullet connectors to the motor, then connecting the three motor wires to the ESC. I also soldered the power wires of the ESC to a deans connector, which would connect to the power supply. I connected the servo tester to the ESC’s signal wires, and also connected the 6V battery pack to the servo tester. After that, it was only a matter of plugging the power supply in and turning up the voltage. 

Upon initially turning it on, it worked perfectly, to my relief. I then proceeded to set the whole system up near the back of my house, where I dunked the motor into a tub of water, and it also worked perfectly. Nice.

After testing, I made sure to dry the motor as well as I could, as while most of the internals can survive underwater, certain parts, like the bearings, can build up rust overtime from water exposure.