My favorite R/C vehicle is actually... Boats! Most of my R/C boats were very slow and had a very bad radio system. Then, I made my homemade Jet Boat, that was very cool and I did a video about it:
But the motor was a brushed one, so the lipo battery (11.1V) fried it.
Later on, I searched on youtube about brushless motors and found that they are INSANELY GOOD. So, I decided to build a brushless R/C boat myself for an reasonable cheap price. It worked well for a while, the motor burned and this project is still in progress...
Here's the video:
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Step 1: Gaining the Materials...
First I bought the Fiberglass hull, that was at a good price (because I don't know how to build a professional hull).
Then the electronics:
-A watercooled brushless motor from banggood - 4000Kv, up to 4S, 4-pole, 15A Max, inrunner.
-The watercooled hobbyking 30A ESC that holds up to 4S and has a BEC voltage of 5V.
-The hobbyking waterproof servo (HK-15269)
-A turnigy 3S battery of 2200Mah.
-The the hk 3100 receiver with a turnigy 3XS radio.
Step 2: Shaft, Prop & Rudder
I found a old large R/C boat that contained two shafts with self-tightening counter-rotating props. It also contained the apropriate stuffing tubes.
For the rudder, I found some lego pieces and a flat rectangular part of a box. I hot-glued them together in the back side of the boat. Then I connected the servo push-rod at the rudder's arm.
Later I used again lego pieces to make a holder for the water pick-up located at the front of the prop.
Step 3: Motor Mount and Coupler
For the motor, I built a metal support and glued it on the hull with heavy duty epoxy (since the motor can vibrate a lot).
Then, I found those wire terminal blocks and removed the plastic case arount it. It was used as a motor coupler.
Step 4: Installing Electronics
I installed everything with hot glue on the boat. The battery was held by a velcro strap.
Then, I drilled two holes on the sides to fit the two indicator leds (red-left and green-right).
Step 5: Watercooling System
For the watercooling, I used small and long tubes that are in the following order:
Water pick-up (mentioned earlier) > Motor > ESC > Out
Step 6: Test Run
I got some problems... The rudder was too small to turn the boat and the motor overheated too much. Because of the watercooling sequence, the water wen to the motor, got very hot and then overheating the esc. one day, the motor bursted into flames. When I took the boat off the water and opening the hatch, all I could see was smoke.
Step 7: Upgrade!
I went on HobbyKing searching for a new motor and I found one that should work. It's the Turnigy Aquastar 2842-2800Kv. I ordered it (+ an 50A esc because the motor is 40A) and while that, I upgraded the rudder with a 3D printed one.
Step 8: Arrived!
About 1 week later, the electronics arrived. I then connected the bullet connectors (everything comes pre-soldered!) then, turned on the transmitter, connected the battery and calibrated:
battery connected > BEEP BEEP > full throttle > BEEP BEEP ... BEEP PEEP > calibrated.
When turning on normally, it goes: BEEP BEEP ... BEEP BEEP. I turned on and it sounded like a jet engine! (because of cooling fan) After a continuous 1/3 trottle, anything heated! Is a very good power system!
Links down below:
Step 9: Motor Mount
I found some old building toys that contained metal and did another motor mount with it. I also used a screw mounting adapter.