New here, extremely small jet boat development :)
Hello, although I am not a professional boat designer, it was originally my childhood dream and have many designs, Ive been working on since I was probably 13yrs old.
I'm currently been developing a functional model jet boat for the last six months. I'm using electric power, but when it comes to models, electric provides far more RPM than a gasoline or alcohol motor can make per pound.
My goal is to make this boat as fast as possible and further develop the jet pump to do so. In the model world, jet boats aren't regarded as fast, however this boat has already shocked many people. It currently runs at 23mph. The project originally started due to my interest in a model that could be run anywhere, even a "raging" stream , which it can, but I've seen these Australian jet boats(full size) that go unbelievable fast.
I thought people here might be interested in this project since it represents sheer overkill. The boat measures ~.75m in length, .16m wide monohedryl hull with ~25 degrees of dead rise.
The pump is a single stage axial jet pump with a 29mm impeller. The motor is just about as big as you'd want to go. If anyone knows about small e-motors, it's a 720 size brushed motor running just under 200watts at 19.2volts and 24K RPM under maximum load.
Heres the issue, the motor does not get up near maximum load and a larger pump would be ridiculous, however the overall setup is not heavy, which leads me to believe I could improve the impeller design or nozzle outlet. I know this because I'm using the maximum voltage for the motor and it doesnt even get warm from running full throttle for 10 minutes. It should be almost hot.
We had someone stop by one of our RC forums and said hey your pump is crude, jet boats can go much faster these days. To which I replied well, what improvements are there. He gave no reply. I've been researching and researching and honestly have not learned to much of any use. The impeller only has two blades, which I thought may be a limitation, however I haven't seen a successful 4-5 blade model sized impeller. Also, I don't know what the maximum pitch is that I can use.
I guess I'll stop here, I don't really know what specifically to ask, but hopefully I can be led in some sort of direction.
To follow I've included links to videos and my build thread, which I know at times seems crude, but it was a learning process. Perhaps the combination of all this will help.
mind you the latest rendition is on the last pages of the thread, since the boat had about 4 stages of development.
the video of of the 16cell version, which is yellow and black is most recent.
more important pics
The boat I recognize is not too hot looking right now, but it's half me changing things and half the result of a crash. So at the moment I could care less what it looks like, forces me to focus on design and not cosmetics. I included a pic of when I first installed the aluminum skid plate, for river running
note, trim tabs were removed(last picture)
I've looked into all of them, the swashdrive isnt small enough, it's meant for 23+cc gas motors. The only nice looking drives are from KMB out of germany, they make ones for electrics. I'm really just sticking to this drive, I've realized most of these drives aren't very different, but the ones made for electrics seem cheap compared to the drives such as a swashdrive, which leads to the whole purpose of this project. To see if I can do better.
For my first step, I've already started work on a new impeller, this one will be three bladed, with a much smaller hub, more blade area and made out of brass. Hopefully it will work.
Here is a Dutch with a collection of model jetdrives
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