Second impeller should run faster and be smaller than the first, for optimal performance.

I'm inclined to say that the cavitation you see is actually just air being sucked in from the loose fit of the shaft. And one more thing, you actually CAN use heat-inserts with resin. Not as good iirc, but doable.

Unbelievable use of 3D printing and commonly available hardware paired with maximum of 5 randomly placed expletives throughout the video to describe mundane phenomena is a recipe for success that I'll always be excited to watch. Bravo!

i find it interesting how software developers make a crap ton of their stuff free. it's very rare that solo devs try to sell their code. but 3d modelers usually sell their plans instead of benefiting the community. i am both a dev and a 3d modeler. i make all my stuff free and accessible.

Hell yeah, yet again another amazing project. I absolutely love seeing your videos and content, and I am inspired by some of your videos to keep up the hard work.

If you used counter-rotating impellers separated by a larger-diameter shaft to keep the pressure up, along with another larger diameter cone following the second impeller, such that the system maintains higher than ambient pressure until the nozzle, you wouldn't get cavitation.

You want the second impeller spinning either in the opposite direction (more efficiency), or faster than the first impeller (more thrust). Otherwise there is no benefit over a single propeller, and actually a net loss on performance. You need to use a hollow shaft to connect one of the impellors, and an inner shaft running thru the hollow shift, separated by a high speed bearing, that way you can run at two different speeds. You add gear teeth to the hollow shaft, and either connect the inner shaft directly to the motor or its own gear.

Great build! You need counter rotating props w/ two motors (gears would be weak, noisy, vibration inducing and steal power). Add a pressure sensor in front of the props, a sensor in between the props and a sensor after the props for discharge pressure. You can then tune the maximum output by adjusting the two motors. Perhaps inlet guide vanes (small and thin) to direct the flow for more bite on the prop - Just like in a turbo jet engine. However the exiting vanes are not needed and are detrimental... Great vid!

If the second impeller is turning at the same rate and same volume as the first impeller, the most you can hope for is that the flow rate stays the same. It’s possible the flow rate is even reduced. Look at the stages of a turbine engine compressor: each subsequent stage is smaller in diameter with more fan blades and the blades themselves are at a greater pitch than the stage before.

You should compare that to the same design with a single stage, one without the second stage, and one with a single impeller thats as long as the two stages together

I watched your channel printing pumps for years , and finally you got a working design!

I think this is the first KZfaq video I've watched where I didn't skip the sponsor product. Infact, it's an integral part of the video itself. Very interesting 🤔

You basically built a mini jetski impeller pump. Would recommend getting a small horizontal shaft gas engine, and use a chain or gear drive to get the RPMs up, and you could slap it on a small boat for a homemade jet boat.

Brilliant work, dude! Really well done!!! 😃 That thing works amazingly! Stay safe there with your family! 🖖😊

3D printing allows the amateur designer to test concepts and build workable prototypes in plastic and metal in a home garage or small factory before deciding on a patent or full scale production. Opens up a new world of mechanical design and manufacturing. I have a new design for submarine propulsion that uses a similar principle but with some interesting twists. 😎🇦🇺

7:30 You could use a screw here. When you will mount a plastic on this metal part, if you have screw it will guarantee your plastic wont break it. We do it on small robot wheels, you snug them in into motor, but to make sure they are tight we screw trough plastic to reach metal part.

AWESOME work! I suggest using a mechanical seal like the ones on home bilge pumps / hot tub pumps. Very simple carbon-on-carbon with a spring! That will reduce most of your air leaks & cavitation

You could put a hole on the side wall beside the first propellor so centrifugal force can push water through a tube connected to a heatsink on the motor so the motor doesn’t overheat.

Water jets are not as efficient as regular propellers. A jet's advantage is that it can run in shallow water. But in deep water, the boat is slower than the same engine/motor and boat with a propeller geared correctly. That is why propellers are predominant.

Good job. You should look into heat-set inserts though. They would solve most of your bolt mounting issues without needing to epoxy things into place.

Brace yourselves. The water Jet unit experts who have never built jet units are coming to the comments 😱

Love your videos. As others have mentioned, the second stage should be different, otherwise this is just an apparent long impeller. You can also do at same speed on same shaft by making the second stage smaller, and have the housing reduce a bit before second stage, this way the first stage will be the intake, second stage the compressor

Volumetric efficiency. It's massive in water jets of this kind. So the leaks around shafts and joints need to be sealed to a high degree of reliability. We see bubbling around the back flange and the shaft will need a positive seal also. Against even an air leak. You produced a really sweet working model, component series here though.

Excellent project

7:06 That´s why you´ll aways need some simple metal machining. Like a lathe. With a lathe, you´d have cut threads on an otherwise smooth rod, cause that´s the way such machines are built. One doesn´t use an end-to-end-threaded-rod, when the threads need to be just on a short part of it.

I noticed that you have a stator between the two rotors. The stator is good as it helps to straighten the flow for the 2nd stage, but it looks like as if the shape of the stator is reversed. The blunt end of the stator aerofoil should be facing into the water flow, not away.

6k rpms is plenty for a jet pump. You should consider optimizing the pump with those rpms. Add a wear ring to tighten up those tolerances of the impellers get rid of the air leaks tweak the impeller pitches and intake duct if needed. Thing should rip with some minor improvements.

You Should Use Venturi Effect In This It Will Improve Efficiency.

You've really come along way from your frist diy water impeller designs! Its amazing to see how much more powerful these new ones are getting! Love it!

Second impeller could be larger if the cavity before the constriction was larger too. The water would want to slow down due to the increase of volume, but the fan would keep pushing it into the constriction

Electrical connectors just chilling in the water while testing at a lake is pretty cool

I might try experimenting with water outlet sizes to get a stronger pressure. Good video.

I’d love a video on resin printers for mechanical use, tolerances etc on common resin printers and all

Buyer be warned, HeyGears printers will ONLY work with their proprietary and expensive resin refills. You cannot use your own resin. I wish sponsors would disclose this.

you should add a lantern ring to the shaft. basically a hose from the high pressure side to the shaft so any air leaks will get filled by the water.

You can use a propane torch on the clear parts to make them more transparent.

Great builder

Oh wow that hey gears resin printer looks incredible i would love being able to get one.

This dude's videos are soo cool! I just wish I could understand one single word!

It is definitely a nice build but you should do a second one fixing the issues and tuning it to better performance(stuff like leaks and clearances can be fixed in a second print). Most of your viewers would be interested in a 2.0 with a test using maybe a stand up board... If you will do it, try to find a calibrated rod for the shaft to reduce vibrations... Nice work!

Ive been wanting to do this to a kayak for a while! I settled for a trolling motor rig i printed

Отличная работа) Я сейчас тоже разрабатываю JET

You should do geared impellers from bigger impeller to a smaller impeller like turbine jet have. water doesnt compress but the compression will shoot the water faster thats why the end impeller should spin faster. At least thats my theory

I think the fins inside the nozzle block water from leaving, lowering efficiency.

Hey my guy. To get your parts to be clearer, just hit em with a quick coat of spray lacquer. Gloss is best. Sanding nearly never improves results that much.

grate fun and learning! thck you for the video

Very very very cool!!

Again, you've got the stator blades in the middle and now in the nozzle at a completely reversed angle. This isn't a pump, it's now trying to be a compressor, which doesn't work with water. You have water leaving the first impeller and slamming into the side of the stator blades, which creates a huge pressure difference on one side and significantly less on the other. This is the source of all the cavitation you can see. This cavitating mix is then hitting the second impeller at an oblique angle, which leaves by slamming again into the stator blades in the nozzle. The water needs to enter and exit as smoothly as possible, any cavitation inside the pump drastically reduces efficiency, in this case it will badly damage the pump over time.

Good job my friend🤝

What would happen if you make it a 2 stage waterjet? Like after this part you built you add a smaller impeller with greater pitch inside a narrower housing and with a smaller nozzle? Would that create a more powerful thrust in the water as the water from the nozzle would come out at an even higher speed?

On the testing footage in the pond, you can see the M5 nuts are coming loose and there is water exiting the housing before the first impeller.

The air or cavitation is coming somewhere before the 1st impeller, either the intake is restricted somewhat, causing it, or the seal is letting air in

Impressive!

nice

Useful tip: you can make FTM printer prints smooth by using a resin and baby powder

Think of a 2 stage pump that you have essentially built, only use jet engine technology or torque converter for an automatic transmission, and the principal of running compound turbocharger system to force air into an engine, jet engines use counter flow to compress the air, heat it up and increase velocity and pressure.

Fantastic

you have little leak on side it would be good make a gasket and stick in there seal it up from grey housing to clear plastic give it more pressure output i think of one thing that wasnt tested was amp and watt and how many draw to sent it full power if it too much amp there going need be bigger mower to handle it ( was hoping for weekeater engine 47cc have top out 16k rpm )

I think you should rethink your design a little. The jet is really just a pump that creates a pressure difference. There are pump designs that create high pressure zones towards the center of the pump I believe. If you use a multi staged pump where each stage is designed to create a targeted increase in pressure perhaps you could create great pressure at sufficient volumes to make it work at lower rpm's. Another idea, what about implementing an outer bypass that goes through a sort of ducted fan and interacts with the high pressure water coming out of the pump, The way the big aircraft jet engines operate. Have you ever heard of Viktor Schauberger? He had some interesting idea's about how water flows in nature. One of his ideas was how to use a fast moving stream of water in the center of rivers to pull river water around bends and minimize erosion on the river banks. Perhaps this concept could be used in a water jet design some how.

Math is not for everyone, and this video is evident for that.

I may not be an engineer but I think you should move the propellers apart so that water can get sucked properly by the second propeller like I'll make a space between them filled with water and maybe it'll boost the maybe I'll increase the performance a bit, idk maybe it works

Küll sa viitsid jännata!

How feasible is it to create a handheld underwater propulsion device (like seen in the movies) using a water jet?

cavitation is a huge energy loss, you might try reducing pipe size each stage to keep water channeled toward impeller. also gears are trying to crush water, thats why they are failing, lubrication is important.

i WISHED i KNEW HOW TO US THAT TYPE OF TECH.

you could make the outlet smaller and it would be a pressure washer

Looks like you're getting some thrust. You should see if you can measure it.

Curious question: This design draws in water and shoots it out above water. How different would it be if it shoots out underwater?

Can we order a unit for paddle boards as transportation to fishing spots?

螺旋槳腔室內部阻力太多 可以試著減低結構設計 導流出水口 可以增加設計引流 可以改善水柱直噴 而非擴散噴發 另外這樣汞噴設計 需要超強力馬達來推動 所以這樣的設計頂多是用在水上遙控玩具 而沒辦法用於載人 動力不夠 如果要載人 結構跟設計還要改善50%～70%以上 這要的設計還達不到商用 因為曾經製作過載人 所以了解狀況

Can the super charger impeller design give the same results?

"I press fitted the bearing" *Shows himself smashing it it with a hammer*

Is there a way to create rapid expansion of water beyond just pressure ???

How cavitation effect resin impeller, does it get damaged quicker?

but total energy/power of the flow does not change with narrowing the pipe, that comes from by the motor impeller, so finally the screw drive worked, can you change the resin color on the fly, per pixel.

Упор создаёт больше с одинарным импеллером или с двойным?

looks like your nozzle can be constricted more since when your fluid comes out it expands like it's coming out at a high pressure. making it smaller should level out that high pressure and also give you more velocity. it could also be expanding due to turbulence but honestly, I think your pump is just that good and can use a more aggressive nozzle.

If I want to print this on my Artillery sidewinder x2, what material would you/anyone suggest? PC seems hard without building an enclosure.

The second stage be on a step up gearbox?

The motor you used to test at the end did 6000 rpm?

You can make RC torpedo boat with that

I suggest making a test stand, water propulsion is famously unstable, and getting a kick at the wrong time could cost you your prototype in the best case scenario.

Класс!!!!

What program do you use to model?

oh you know what would be cool if you did a slow-mo of the propeller's

How can you revers this so you can take power frome moving water like a river or a water fall?

Good ....❤

I like your english accent, clear and easy to understand for me as an Indonesian people. Thank you👍

Will you make a jet boat with you inside for the lake?

We need a rocket bersion of this.

Can you do counter rotation ones next

I’m surprised by how much air is in the flow

How much trust does it generate?

nice project you have there. Thanks to your transparent jet housing, you can clearly see that there is air in the propeller housing. This is very bad for your efficiency of your jet output. make sure your entire water inlet until your exit is water/air closed !!

I wonder how much thrust was made

What if....you had the first impeller feeding the second but a second water input channel feeding the second and hopefully forcing more water out of the nozzle

Did anyone else just scream when he filed backwards?

Simple , switch out the gearing , one big one small double the oomph

Le faltaría poner un estátor para que contrarestase la rotacion del chorro del agua

Pode disponibilizar o arquivo stl para impressão?