I finally added the RC controller and a battery pack into the Tri-Boat and tested it for the first time.
I made some changes to the assembly:
I designed and printed a new set of propellers which ware easier to print and perform better. If you print the new propellers there is no need to add support, it is included in the model.
I also replaced the propeller's shaft by a piece of a radio antenna and used a small piece of a bigger diameter tube from the same antenna as a sleeve for lower friction of the shaft.
Please see my new video in the following link:
Due to the limited load capacity of the previous design, I've decided to increase the floating volume of the three boats. In order to do that, I decreased the wall thickness back to 1mm but added internal walls to make it printable. I also increased the volume by enlarging the boat. as can be seen in the pictures and videos, the load capacity increased by 37%. For the previous design it was 92.9 gr capacity for one boat and now it is 127.8 gr.
Hi, I designed this boat in order to test the ability to reduce water friction while improving stability. I started with designing the boat; same boat for all three places, but one of them is a mirror. at first, I made the wall thickness of the boat too thin (1mm) so I couldn't print it well. then I tried to make it thicker but not too much so it won't be too heavy. I ended with 1.5mm thickness which gave a boat which weights 19.2gr and has a floating ability of 82gr (calculated by the volume and water density). Then I designed the bridges and tried to reduce as much weight as possible. The blue parts were printed in MakerBot 2 using PLA and the red parts in Ecksbot using ABS. The boat is turning by rotating the front boat around the vertical axis using a servo motor. The boat is pushed by two motors in the rear boats. The total weight of the boat (including servo motor, two motors and stractural parts) is 192gr.
As it can be seen in the video files, the friction with water is very low and the boat can reach high speeds.
The assembly is straight forward. each part is attached to other using one or two screws only. I used a paper clip for making the steering bar (which connects between the servo motor and the front boat). for the propeller rod, I used a cloth hanger (2mm diameter) and connected it to the motor which a piece of plastic tube. The two motors are electrically connected in parallel. It is possible to separate the control of them and try to make the boat turn by operating them in different speeds.
In the test of the assembled boat, I figured that it will be to heavy if I will add the battery and RC receiver, and I have some ideas how to solve it:
It is possible to make the three boats with a little higher walls. also it is possible to use smaller servo motor and receiver. The battery I used for the tests is a 3.7V li-ion, one cell of 18650.
I painted the boats from its bottom side in order to prevent water leakage and improve its look.