Homemade Jet Unit Build, part 5 Double the POWER
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- čas přidán 23. 07. 2024
- Homemade jet unit gets twice the power but not twice the results , I install a 13hp 420cc motor hoping for some serious speed but didn't work too well.
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This will be one of those......Do you remember when's with a smile.. Good job
love you're patience and persistence
Fun in the shop
Great
Sharing those cool builds / learning experiences / memories with your child.
Priceless
Love this channel! Bursting with creativity! Bravo man keep the videos coming!
Thanks! Will do!
Make a thing in the back that you can stomp to clear out the grill. Look it up for jet boats. It's a thing
Yeah a stomp grate . They work pretty well but on a boat this small I can’t even stand at the back. Could make it work I guess 👍
@@DktheWelder you don't need to stomp it.. may not be a good idea anyway with a thin aluminum hull. Maybe a handle like a drift car e brake?
Maybe it'd be easier to just make a tool so u don't need to stick your arm in the water
ORRR a super dumb idea.. use a mesh to cover the grill(very large mesh size, like chicken wire maybe?). Just slide the mesh to the side for a fresh section
Bro I just discovered your channel and the boat videos are super rad!!! I have an sps long tail and have experimented with jet drives myself!! You have given me some ideas, and I don't think you should abandon the boat content!!! Hell ya from America
The boat content is going to keep coming just a big back and forth at the moment, the sps longtails are great I never got the jet unit working well . Did you see the chainsaw surface drive? It works really well, I have another idea that I will try soon
Hillbillies forcing things together every 5 minute with a hydraulic press, jury-rigging boats and putting that boat inside another boat to test it, doubling the power to solve problems, terrifying local ducks, stranding your children in cut-off boat segments..
Great family friendly content.
haha thanks!
One helluva way to water your lawn there dude.
The fact you made a boat in a boat gets my like.
I think I need to make a pond
I like the boat bed test set up!
Yeah I wanted to put a scale on it to test how much thrust each setup makes! But then I thought it would change as the boat moves through the water faster so it would only be a stationary thrust test
Nothin’ better to do at work. Love it
SWEET. Ironically u use a fish weighing scale to measure thrust♡ This IS MY FAVORITE JET CHANNEL
That’s exactly what I wanted to do but didn’t have time to buy one lol, thanks been a cool project hopefully I can figure it out
Keep up the cool projects man you figure out what u can do next
Thanks! Will do!
Don't give up and never give in 😎
Hey back again lol! checking your progress lol! I see you went 4 stroke! Your output nozzle is way to high up to be of much use. Looks like it's directly flat out the back. should be on a 9 to 12 degree downward pitch to push the boat forward only 1/5 of the output should be seen above water in ideal functional conditions! your losing 1/3 almost of your total thrust to making a rooster tail! That is why most river boats can up and down the pitch to go up through rapids or on flats! The slight downward pitch will push the ass of the boat up out of the water and forward. Creates less drag and more forward motion! Funny enough I have a 1/4 scale about the size of your little boat lol! 5.5 foot long* 2.4 wide. 2 blade 130mm jet pump prop. 125cc 2 stroke. Was the reason first started watching though was large scale rc at first lol!
I didn’t realise the angle had that much effect ! I also think the jet unit isn’t very well made , I am going to try a surface drive and then come back to the jet unit once I know how to make it work properly, thanks for the advice!
@@DktheWelder pitch up and down makes huge changes in how it moves the boat! Other thing! impeller is very aggressive on this build! I went all in 3 blade huge one on my first build lol Burned up tons stuff! Went with a 2 blade very slight wave design prop second go! higher rpms and less motor load. Gained actually tons of speed! And nothing went super nuclear lol!
You need a set of "Clam Shells" on the jet to enable backing up. They would be open when going forward and closed directing the water forward for reverse.
3:24 thats some dope cc
Love your videos man! Great building skills. By the sounds of it the motor doesn't have enough torque to reach higher rpm and its true power potential. However your gearing choice for 8000rpm is good for a jet pump.
I think you need to go less pitch on the impeller, your impeller seems to have a lot of angle on the blades. Lower pitch will not only allow the motor to reach higher rpm, but will also increase how much water pressure it can generate, which should result in more water being pushed through the nozzle and therefore more thrust. If you had access to a 3D printer you could use that to print out a nicely balanced more efficient impeller.
You are saying exactly what I am thinking! I was thinking of getting a 3D printer to experiment with different jet unit and impeller designs then make a metal on once I know what to do. I don’t want to use that heavy motor but the smaller 6.5hp in the other videos which probably does around 4000 to 5000rpm , how would I make the pump work at those rpm? Or do they need to spin fast?
@@DktheWelder You can make a pump that will plane at 4-5k rpm. The tough thing about having low rpm and power is getting high speeds, because the water velocity is usually slower out the nozzle, but it will be fine for planing and cruising. Since you have low rpm, you will want to go with a slightly larger diameter pump, and also keep fairly high pitch on the impeller blades to keep the water velocity up. 20% less blade angle could be a good starting point.
I use the reality CR-10 3D printer and once you get it dialled in it works great.
@@jakebarnhill6308 o cool! A 3D printer be good for experimenting then make it out of metal once I figure it out. I have a huge chainsaw motor now that apparently does 12000rpm so hopefully try it on the weekend
@@DktheWelder haha nice! That chainsaw motor could be a more ideal power plant, powering a small 90-100mm jet you could some decent speeds.
I guess cooling might be a bit more of a challenge with the chainsaw motor. Could always wrap some copper pipe around the cylinder or something.
@@DktheWelder id say ashallower pitch impeller would do it a world of good look at say a jetski impeller for reference
Nice work man! Not sure what the best route from here is for ya, the constant clogging seems to be an issue so maybe the surface drive would be better. Unless you can find a jet drive from an abandoned jet ski or something. Lots more to them than just the size. Complicated maths. 😂
I know they are tricky to figure out ! Even a JetSki unit would still block up in the type off rivers around here have weeds in them , I have a bit of a plan !
It might also have something to do with rpm, you can have as much power as you want but if it only spins the same speed it wont go as fast?
The physics of rocket propulsion has dm/dt in the equation, which is delta change in mass being trusted per a time rate.
Is cavitation of the impeller being spun at a 8K RPM a possible reason for not seeing an improvement? Just seems larger diameter impeller and nozzle, with enough KW power to drive it is needed. I'm amazed at your simple used of a hammer and edge of table to curve sheet metal into shape. Nice build!
I don’t know about that rocket propulsion stuff ! But I think your right the whole unit needs to be bigger. Thanks 👍
I would need to compare footage before and after your wheel mod. Watch the footage, are they creating some drag? I see spray coming off both corners of the transom
Yes I think they are creating drag but once on the plane it should be ok I thought it would plane easy with that motor. It goes 30kph with three people on the bigger boat I’m using as a test tub using a longtail setup with that same engine
its all about moving a greater volume mate time for a bigger jet drive and maby a gsxr 1000 power plant hehe
Or just buy a JetSki. I want to keep it nice and light for the little rivers
@@DktheWelder thats the way man they gotta be light jetskis r fun but impractical in a little creek our little boats rock and building sh$ts fun
Would it help if the jet was deeper in the water... and the front of the intake where a little less abrupt.
yeah lower jet unit smoother intake and bigger diameter all thinks that would make it go better i think , thanks for the input👍
Height of exit should not make any difference, it is the mass flow that provides propulsion so you can shoot the water above water and get the same thrust. So I would focus on the intake design to improve flow and tune the output diameter to achieve desired speed of the boat. Only way to increase thrust is to either move more water at the same speed or move same amount of water faster, at least according to physics.
I heard it got down to -2c in Melbourne yesterday! That's crazy, the last couple of days here in western Canada have been around +30c
I’m in New Zealand which is colder again we have had a few frosts in the mornings, but the rain is the worst it rains all winter here in waihi is one of the wettest parts of New Zealand but it will bring the rivers up!
Yep here in melb in lockdown doing school right now and just Beeing super cold😢
@@DktheWelder I don't know why I confused Australia with New Zealand. I'm sure you like that about as much as Canadians like being confused with Americans lol
@@BruceLyeg yes American and Canadian accents are similar but I like the Canadian way of talking. And everyone in New Zealand likes trailer park boys haha
Nice one mate
Thanks 👍
I think one of the reasons why it was going slower is because that 13 horse motor didnt have enough torque to spin the impeller with the water at the gear reduction it was at, theoretically it would spin at 8k RPM however thats under very little if any load, maybe try mounting a dirtbike engine with its transmission up to the jet and see how that goes?
As for the grating clogging up a lot try having some way to put the impeller and stuff in reverse, if you can do that it will back flow water through the nozzle and out the grate clearing any debris. Really interesting build though, im sure it'll be quite fun once you get it all set up how you want it.
Thanks! It is a great project and you are right the gear ratio was too high and the motor couldn’t get into the power. But that motor is too heavy lifting up and down river banks , I am working on something at the moment that should solve most of the problems I hope
@@DktheWelder I look forward to that video, do you plan on building a water deflector for the nozzle so you have a neutral position and a reverse position as well as all the way up for forward?
@@The_JEB a reverse bucket! I was going to build one once I got it all working properly
@@DktheWelder if you get it set up right you'll have the nozzle pushing water for you to go forwards as well as into the bucket to go backwards which would effectively give it a neutral position as well, that way you can start it without worrying about the boat taking off on ya
5:27 loved the kick by the jet there, maybe redirecting the jet stream upwards, rather than shooting it into the water, could help with the speed
It seemed to have heaps of power in the tub of water but didn’t go any faster, I was surprised at how bad it went I have run that motor in my bigger boat with 3 people at 30kph . I think my jet unit is too badly designed haha
@@DktheWelder 3 people with an open prop, right?
@@Eden_M yes with a longtail motor with a surface drive prop
U need to put the jet lower in the water to get its full thrust potential
looks like it ist not getting on full RPM. check the small levers on the carb. have the same one and it runs on much higher rpm like double or so
the governor is by passed and its getting full throttle , I made the gearing too high so it couldn't get into the higher rpm . I think it would have got on the plane if I got the gearing correct but this motor is too heavy for carrying up river banks and over obstacles , I am working on something at the moment that might be better the video will be out in another week or so, thanks for the comment
Try to increase square of water intake. It will reduce propability of mailfunction which caused by scrap grass in intake.
Try a predator 670 not to heavy but a 22hp v twin thats oil cooled and turn key
I think the nozzle should be submerged deeper.
A few people have said that , I think lower the whole unit and angle it down a bit
I don't know if you have heard of the Blenheim River Queen? It's made to look like a paddle boat, but actually has a pair of 25hp Honda outboards hidden in wee compartments on each of the rear quarters. That used to constantly clog the propellers with weed and it was apparently a huge PITA clearing them. The boat has gone south to Christchurch now, but it never made the owners any money, and that was partly because hoons used to smash its windows and break in an steal booze. It seems to me that your biggest problem is too much resistance pushing that slab of a hull through the water. It's more like a raft than a boat, and it doesn't look like it has the shape to lift the bow and get it on plane. I know you'll keep at it till you make it fly though.
That hull is actually fast . It would plane with a 3.5hp outboard and plane two people with the 6.5 hp longtail . But my jet design skills of just making it up as I go aren’t really the best haha , but even so the weeds would still block it up even if I had a JetSki unit. I’m still thinking about the next step I have a bit of a plan and another motor option
Reduce the pitch of the blades to let the motor rev higher into its power range or put a bigger motor on it
may be a little late now but just tape a scale on front of it while testing in the bigger boat then you know the weight is actually pushing
also you got a smat dauther it semes :D
thanks! I was thinking that but couldn't be bothered getting a scale haha
Have you tried using a 30 series torque converter
that would probably work!
Just wondering if the jet sits in the water ot might push it better
It could do there is something going wrong hopefully I can figure it out and peoples comments help as well thanks 👍
The jet drive definitely needs to be further in the water your water pushing out of the jet drive pushes against the water itself your essentially making a big water pump
2 stroke dirt bike/snow mobile motor ?
A 2 stroke dirt bike motor would be good
To silence it put the exhaust in the water
Stuck at a cross road road for sure, the 420 is deffinelty heavy. Try the surface drive and remove the govenor. This way you will be able to swap and change the prop for Max thrust and not ring its nut out. Failing that a redesign.Your bloody good at what ya do that's for sure
Yeah thanks! I have 3 surface drive props I can try so should be able to get it going fast , I want to make linkage arms so I can face forward and have like a joystick to do pitch and steering in one ,hopefully I can get it to work
@@DktheWelder don't let it beat you ! There's deffinelty a way... the joystick idea is awesome id think the pitch will be difficult but not impossible
This is late but I just found you channel you can get upto 50% more volume of water by using a bigger diameter steering cone according to the Bernoulli effect In fluid dynamics, Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluid's potential energy.[1](Ch.3)[2](§ 3.5) The principle is named after Daniel Bernoulli who published it in his book Hydrodynamica in 1738.[3] Although Bernoulli deduced that pressure decreases when the flow speed increases, it was Leonhard Euler who derived Bernoulli's equation in its usual form in 1752.[4][5] The principle is only applicable for isentropic flows: when the effects of irreversible processes (like turbulence) and non-adiabatic processes (e.g. heat radiation) are small and can be neglected
That’s some complicated stuff! I tried a smaller nozzle because the motor was running too freely but really need to make a jet unit. I can’t really find any good formulas to help design a jet unit properly for a low 6-10hp motor so I might get a 3D printer and have to do trial and error
@@DktheWelder basically you could build the can that you use to steer with about 2 to 3 inches bigger gap between it and the nozzle then place the nozzle end mid point in the steering tube. This will cause extra water to be sucked into the steering tube and blown out with the jet. They used to build a tire inflator with that principle and it would fill a tire 50% faster. There was a story on it in popular science back in the 1980s
What you need is more revs not more power. Valiant effort but focus on getting higher revs......
I had it geared for more rpm but was geared too high the motor never got into its power at higher rpm. I think if I geared it about 1.8:1 instead of the 2.4:1 it would have worked
@@DktheWelder Possibly but I am unsure. These jets really need MASSIVE revs to work effectively. I read somewhere today that someone is changing back to their original electric motor because the 18.2k revs is not good enough compared to the 27k revs of the original motor......Trying going electric my friend. I wish you well with it and thank you for the great videos :-)
Hi guys - I just came across your video and I love your idea and fabrication is impressive - wow, but that being said - am I wrong to assume that you have one giant fundamental issue and it is the fact that the exhaust part of your jet is always above the water line and thus waisting all the power... if you somehow redesign it and make sure that that exhaust part is always under water, than you should get real propulsion; otherwise you just shooting water in the air...
Every jet boat has the nozzle above the water line when planning they can usually adjust the nozzle up and down a bit to trim the boat , although my one is a bit too high . I am using a propeller setup now which is way more efficient but would like to go back to the jet unit once I have more knowledge on it
Sorry for you here is almost summer with Blu Sky and the CV axle could be a good thing to try
I hate winter, but the rivers will be up soon from all the rain should be good once I get the little boat working properly!
Having a CV joint in the prop shaft sounds scary to me.
@@DktheWelder also Yesterday Simon from rclifeon had the same problem with putting the boat in a waterskipping position czcams.com/video/PiisxsWiEok/video.html
@@TrevorDennis100 would a universal joint be better? I’m looking at another motor that does 12000 rpm don’t want it to explode haha
@@jeremyperraud1357 yeah it’s like putting heaps of power in and going nowhere! I know this hull is fast though because with the outboard and the longtail it went pretty fast with hardly any power . I’m wondering if the jet was just pushing at the wrong angle and cavitation problems and sucking up weeds . I watch the rc guys a bit because they experiment with things a lot best way to learn
are u removing the governer from these motors? more hp isnt always going to be faster. in your case rpm will make it fast u want to spin that fan per say as fast as u can the faster the more water will be moved good luck!!
I will like to buy the yet unit from you if possible?
I am not selling this jet unit as it doesn't work properly
How about rpm, you increase power but rpm not increase, the jet drive still same
jets like that are alot more inefficient than a simple propeller i belive so even if you got a perfect system you would need more power to go the same speed as just with a normal prop, aswell the issue with the intake been clogged with weeds
You are dead right! I’m moving away from the jet unit for a bit because of those reasons. I will revisit the jet unit but a normal propeller is better have you seen my chainsaw surface drive videos?
Remove the governor on the engine that will help a lot
Put a buller built 125cc motor on there it’s a 2 stroke beast that makes 55hp I have one on my race kart
That would definitely get it going, and be light weight!
That chain is way too tight, try a longer chain with a tensioner and it should help it rev through to it's power range.
Man I want to build a lightweight boat with a jetdrive and a Honda clone so bad. I think that your gearing is too steep. 2.4 : 1 is taking it out of its powerband more than cutting its hp in half. I think you should play with a belt and 2 adjustable sheaves that way the motor can hit its max rpm
Yes the motor wasn’t reach its power I was thinking of changing the gear ratios but I have a feeling there is something wrong wit the jet drives design. Also I want to use on of those 6.5hp motors with direct drive and make it get on the plane and work properly it should have enough power just a matter of making the jet drive suit it
@@DktheWelder I wouldn't say i
There's something wrong but they like ~6000 rpm. The main issue is the motor is overloading at too low an rpm and it doesn't make enough power to overcome it. I bet it would get on plane at 1.5 : 1. Which would be easy to achieve with 2 adjustable sheaves and 1 belt. You could get them from an a/c supply house for a commercial HVAC blower. I've thought about this a lot lol
I think the whole jet thruster unit thingy is too small
Side vents
You need a bigger prop not a bigger boat
Why don't you try putting the prop inside the jet drive instead of a homemade impeller, you might find what you're looking for
hmmmm after all that work .....might be a matter of pump design so no matter how fast it spins you wont see the result you want. Surface prop is a easier solution...maybe :-)
I think your right, there is something wrong with how the pump is designed but I’m not sure on how to fix it! I will keep researching for the next design and in the meantime get the surface drive going because that interests me too
Your rpms are not high enough, just get a 15 hp outboard... you'll cruze!
It was way quicker with a 3.5hp outboard in another video. 15hp would be dangerous haha
wider boat is easier to plane ;)
это у вас творческий бардак в гараже?
да!
See the problem you’re gonna have is jet drive. Systems are terrible inefficient. A prop or a surface drive is definitely going to be your best bet if you’re not willing to upgrade to a JetSki drive line. At my company in Rocky Creek, we’re currently building these mini jets. And the lesson that we have gathered, is you always want more power. You’re simply not going to get enough from a lawnmower engine. If small engines is what you need, you need a prop awesome fashion.
Yes I have been put off the mini jetboat thing I want a boat I can carry and plane , I have a 5hp outboard now which is way faster than. I think it needs to be a trailer boat if it is a jetboat 👍
Daniel; jet boats have hei place to e sure, but h maneuverability and lack of prop to clog (Yup, jet drives don't like some weeds, but a little more robust will chew up a few of them) Just for fun, see one of my favorite channels while he rebuilds a jet drive unit.. larger impeller, maybe able to chew some of those weeds??: czcams.com/video/AVf9SS5Gu2g/video.html
i still love your experimentation & spirit! KEEP ON!!
Maybe you're impeller design needs a tickle
I think it does, maybe a direct drive with a more aggressive impeller or a two stage could be the go but the weeds are still going to be a problem
@@DktheWelder no lake near you?
@@theideasman6018 there are some lakes but a couple hours drive the sea is only 10mins away but an outboard is better for that I want to explore the rivers but didn’t realise it would clog up this much . I can still use the jet unit for another project in the future
Pit that two stroke in! Get the rpms up! Problem isn't the power here. If you don't get the rpm up. You are not going to go faster
that kind of motor is torquey not speedy.. try motorcycle engine..
I’ve just watched all the jet boat videos up till this one. My opinion about it not working (lack of power) your jet needs to be under the water level, you’re just spraying the jet of water and it’s not pushing against anything to give you the forward thrust.