Yes, I already made an aluminum ride plate, to increase jet performance and also to increase the lift at the rear of the boat because right now it is too rear heavy. Hoping to test it soon

@@rcandfun242 awesome 😎 looking forward to your next video.

It's custom support, so that a fdm printer can print the blades as bridges. You can remove the support later to sand the impeller blades

PLA, unfortunately... PETG would be a lot smarter but my printer struggles printing it with a .6mm nozzle.

@@rcandfun242 use pa 12 with carbon or fiber

@@julienhagen7411 that sounds strong, but quite abrasive. I doubt my printer could handle it, but if yours can, it's surely a good idea

Good question. Of course the max. RPM's depend on the strengh of the 3d printed Impeller and the concentricity of the drive shaft, the resonance frequencies and dampening of your machine, etc. but since the diameter is only 80mm it should'nt be such a big deal. I had'nt had issues with 15000+ rpm so far. For the efficiency, the lower the speed, the more energy efficient it gets; for the power limit (when the pump starts to cavitate) that I don't know, it seems like a lot more power is needed for this pump to start cavitating.

If efficiency is your number 1 priority, I would'nt recommend a jet drive (for this speed or vessel sice at least) because it is quite inefficient compared to a big-prop tralling motor. The advantages are the shallow draft, no risk of injuy and (if enough power is provided) a higher top-speed. Dynamic thrust is hard to measure if hull resistance is unknown and static thrust is a rather useless number unless you wanna build a helicopter imo, but the jet consumes about 2.5 kW at full throttle (22.2 Volt, aka 6s battery) and I haven't measured the speed yet but I estimate the current setup (->update video) can do 15+ km/h. I am now waiting for a more powerful speed controller (12s, 400A)for more speed and power and hopefully less overheating issues.

@@rcandfun242 thank you for information. I will build something similar to kontiki

Engineering is all about compromises... I think the energy density gap between fuel and batteries is less of a problem on this small scale, that's the reason we see electric scooters and bikes with remarkable range etc. but no electric long range planes or ships. Anyway my idea here was to have something that can do both, going slow and efficient with a big(ger) 80mm jet pump and if I want to go fast I can simply switch to a higher voltage battery. The advantage of an electric motor vs gasoline engines, apart from being environmentally friendlier is, that it is efficient at almost any rpm

@@rcandfun242 well i agree with allot of your points but saying it is easy to make a fast jet of water efficiënt and silent. Besides have you calculated how much extra energy is required to plane your displacement hull? Powerful electric motors and controllers require allot of current so you either need a high amp high voltage battery or a very large one. For some hull designs it literally requires 20 times as much energy to make them plane. Weight is especially important. Im a sailor tinkerer and ebike builder. I'd be interested in a silent long range mud/swamp proof kayak with high efficiency. A small volume of water at high speed is noisy and not effciënt if you're traveling at displacement hull speeds. The advantage of a jet drive are that you have nothing sticking out, that you can steer the jet stream instead of a rudder making them perfect in theory for shallows. Have fun building

@@MrJob91 You made some good points, a jet kayak can be useful in shallow waters even if it is not very fast. I think the heavier and bigger the vessel, the more energy is required to get it up to speed and on plane out of the water because when scaling up a hull, the lift force increases with the surface area (when at the same speed), so the scaling factor squared, but the weight increases to the power of 3. Furthermore, the more lift is required, the more drag gets created by the lifting surfaces themselves further increasing the power demands. I haven't calculated the lift force of my kayak, but my hope is that such a light craft (100-110 kg including the driver) should be relatively easy to get on plane, especially when much heavier motorised kayaks of comparible size (mokai, aquanami...) can do that too with less then 10 HP.

if you want efficiency, you have to throw the jet pump overboard...a big, slow, directly driven propeller on a long shaft like on a Thai-style boat is more efficient, but obviously at the cost of safety and convenience.

Snowmobiles were not designed to plane on water either yet they do just fine. With enough speed and power, virtually everything can be a skipping stone. That being said it could be true that I need to add additional lift surfaces on the rear and trim the jet stream down a few degrees, since the kayak is very rear-heavy, to achieve a lower plaining speed. But plaining or not I first need to wait for bigger batteries before I can continue with more serious testing. Unfortunately the supplier has logistical issues right now so it might take a while longer...

fdm-type. Creality CR-10 with .6mm nozzle

The new ones last so long that I can't tell yet. The small rc batteries in this test only last like 5 minutes...

You dont have to buy the parts, I made them available for free on thingiverse (link in video description). And for the electronics, I am still experimenting. Right now I am using turinigy batteries (hobbyking) a 56104 tfl motor and a 180A hobbywing seaking esc

thanks for the interest in this project. As a disclaimer, since this all is highliy experimental and still under development, I would not suggest to you to copy everything I did 1:1 , if you want to build something similar but instead see it as a headstart for your own project. Jet unit: 3d prined (link in description) Motor (as said in the video) is a 56104 420 KV brushless inrunner from "TFL (SSS Motor series)" The Speed Controller is a "Hobbywing" 180A 6S Seaking ESC (but tests have shown it is too small which was not too unexpected as I explained in this video) new Batteries are "Turnigy" 20Ah Li-Po 12-24C (from Hobbyking). RC Controller: good old "Traxxas" TQI . new Servo: generic 20kg/cm standard size servo. Bearing: 608 2RS skateboard bearings with marine grease. Drive-Shaft: 8mm V2A stainless steel, as well as all screws. Kayak: old Robson PE Kayak (they probably dont make them anymore) I hope this answers your question in enough details otherwise feel free to tell me what parts I missed.

Impeller diameter is about 80mm

Thats a very kind offer, thanks. I have a channel e-mail: rcandfun@protonmail.com

@@rcandfun242 message sent

Ive been in this venture for few straight years now designing and creating high performance pumps @ 60mm and you would be shocked what my performances have been

@@blakeylambrix3205 let me guess, since Youngster's Jets.