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Try this with a aquarium water chiller to keep temps even lower. Tomatoes are disgusting!

if your water cooling, intake goes on bottom and output ontop so your device totally fills before it can empty that way you dont end up with air pockets which dont cool anything.

As someone who works with liquid hydrocarbon on the daily, I just about had a heart attack when you said you were going to use it as coolant for a sparking fireball engine

Hey Joel, I just noticed that the electrodes are probably causing a lot of heat transfer to the resin. Maybe try a ceramic tube or slip coating to isolate that heat from the body part.

Now try this with liquid nitrogen and metal 3D print to keep temperatures even lower!

Hey integza, I had the same idea as you a couple years back and designed a water-cooled jet engine as well, but due to not having an SLA printer i was unable to give it a try. I designed it with a spiral water cooling and perfectly sized walls so that maximum cooling would be created. If you want I can send you the files if you are interested in trying out my design. Just let me know. :) Update: Seeing as you guys like this idea, I should also add that I also designed it with tangential air and fuel inlets as to provide an extra layer of protection by creating a boundary layer of insulating air. I saw this concept used before on a 3d printed rocket and it worked to some extent.

Try to make a controller, this is what we actually use even in the early stages of jet engine builds. This helps a lot to understand what is going on inside the engine and by comparing this data with your design and materials used, you will know what is the problem and how exactly it can be solved. Helps to minimize the time you waste on prototypes and obviously the cost of materials used. the most basic one would include at least 2 thermal sensors (we use 2 at each stage of the engine for better results, but it's not really necessary for your needs), in your case 1 would be used inside the engine and the other one on the nozzle (just an example, you can play with it), AR sensor that would show the exact mixture (this will allow making it more efficient (by that I not only mean consumption but also temperatures (that are quite important in your case) (because the good mixture will decrease temperatures of combustion), air flow sensors (show the speeds of intake air etc.) and the last but not least is flow/consumption sensor (but it mostly used for liquid fuels, so not sure if it would be helpful for you. (If needed can help with code etc.) thank you for your videos.

Should use a ceramic spacer/O Ring to hold your diffuser to prevent the heat transfer from the metal to the resin/plastic

The butane coolant was a great idea. It was perfectly effective at producing content

I can't believe you used liquid butane to cool a combustion chamber made of plastic, that was brilliant! 😂 P. S. : that keyboard is filthy!

It would be interesting to watch it run with a infrared camera and see the efficiency in each design change.

You accomplished what I would think impossible. A Combustion Chamber made of plastic/tesin. I'm thoroughly impressed. Thank You for sharing this.

Don't forget to vent your cooling loop (so that there are no air bubbles in the loop). That increases the cooling efficiency. Also you can try to utilize the fine internal structures you can create with SLA to create a unibody engine, eliminating the mount which will always be challenging to watercool. You can even do some flow simulations to find the form which best circulates the water without any hotspots. In your current solution the flow seems to not cover the whole engine.

Some Ideas: 1.) Run the engine “fuel rich” so that it can’t burn the plastic as well. 2.) Machine a Graphite Nozzle (and maybe other parts (combustion cylinder, diffuser disk) if that doesn’t work on it’s own) 3) As others have suggested, optimize the coolant loop (better path design, less bubbles, maybe even a faster pump / more volume; a bunch of cool 3d printed pump designs exist too, that could maybe be a video in of itself!) 4) Cool the water down with ice (and maybe even salt water to get it even colder, although I don’t know how that would effect the plastic, and what would happen if it gets in contact with the fire) 5.) Do the vortex cooling as well? (I don’t know much about this method, but it sounds like combining the two may be good!) 6.) Use Gaskets 7.) Use fine metal mesh as a flashback arrestor, or maybe even a commercial flashback arrestor like they use for Oxy-Fuel torches! 8.) Fancier Injector Design to Make Sure you are having things mix well That’s about all the ideas i have, and it was a great video as always!

Love it! I had recommended water cooling over a year back, so glad to finally see it attempted. Oh, and using the fuel to cool the engine is pretty much what NASA used to do, they cooled the bell nozzle (and I think the chamber) with the fuel before sending it into the chamber. Of course, they had a much higher flow and systems that could handle MUCH higher pressures, so it might not be a great idea to implement in plastic.

I'm really glad you make these videos as you so, it's super fun and I learn a lot for both you and the comments. Cheers mate P.s don't use liquid butane to cool a fire!! That's really dangerous the amount that's going through!! You could try having it so that the water comes in the bottom and has to take a longer path around the jet, think of a spiral from front to back.. water flowing over every surface. Keep it up! P.P.S a radiator in an ice water bucket would be more effective for cooling then flammable liquids and gasses

I think you should make a nice pair of safety glasses to protect your eyes from exploding plastic jet engines. After that you could look into cooling jet engines with something like liquid nitrogen.

@Integza: you should build a shredder to destroy all the tomatoes.

Love to see your videos. You do a great job in describing and assembling your projects. Hopefully the water cooled jet will get to the point of complete success.

A cool idea I could think off is trying out all your differnt engines and seeing which has the most thrust and some different challenges for your engines.

if the resevoir is higher than the water jacket, it will vastly increase the efficiency of cooling because the air bubbles will be able to travel up to the res and leave the system. that frothy mix of water and air in the water jacket is really bad at conducting heat

I got the impression that the engines might have worked a bit better if you pumped the water in on the bottom and out the top. That way the water would carry all the air out with it as it exit. It seems to me that the engines failed at the top and that might have been because there was little cooling there with all the air trapped in the upper part.

I’d love to see you stay with this one. You are so close to success! I think the metal diffuser is conducting all the heat from the combustion chamber into the flange. You would need to somehow cool the diffuser.

using butane to cool a combustion chamber is a Darwin award in the making

Using a flamable gas as a coolant is one of the greatest ideas I ever seen ♥️ love from spain

Woah, nice graphics on this one!

Fun fact, some rocket engines are liquid cooled in a way similar to the liquid butane attempt, it's known as Staged Combustion and it also helps with efficiency since it preheats the fuel before ignition.

People used to put butane and explosive fluid in car hvac systems . As soon as you said butane , I had to wait for the fun!!!!

Would warm water help keep the resin from being brittle/experiencing some kind of thermal shock from the temperature differential?

A simple improvement would be have the water enter from the bottom to the top, other little things is have the water jacket have a larger cavity at the top as well as a larger outlet to allow the heated water and importantly steam to escape easier. The complicated improvement is to have the water enter the chamber to cool internal components as well as using the steam as added thrust mass.

I was thinking, it might be easier to try a valveless pulse jet design with this water cooling method. I always enjoyed watching your videos, keep up the fantastic work brother!

Cool video! One idea is to make the plastic flanges hollow in the middle and seal them against the metal plate with o rings. This way the water cooling can also cool the metal plate and stop it from melting the housing.

there was way too much air in the water cooling loop. at least in the first few trys. I think thats the most likely reason why the last try was so successful. and if you want to improve the cooling further, instead of redicing the wall thickness, try increasing the surface area. adding fins within the water channel would help tremendously. and why not watercool the diffuser as well? get water close to that metal from both sides to keep that one cool as well and I think this could work really well.

Some improvements that I can think of straight away: 1. Make sure the water inlet is from the bottom and therefore has a more continuous area of contact with the resin when under temperature stress. 2. A higher pressure of cooling may be required due to what seems to be melting points happening at the point of one of the cooling in/outlet. Maybe reinforce this area with small vanes to distribute that water evenly. Also maybe get a thermometer to test the temperature of the water in vs out to see how well it is working. 3. Use tomato juice to assert your cooling dominance ;)

I'd really love if you'd make tutorial about how to create 3d designs or maybe some basics on jet engines,etc.

You can try to use coolant instead of water, also try some thermal paste to seal the housings

Put the water inlet at the bottom and the outlet at the top, pump the water upwards. It'll remove all the bubbles and completely fill the cooling chamber. Your problem could be hot spots forming when the water boils or has bubbles in it. And for a less explosive coolant, try car antifreeze. Although I do like how when the engine fails it puts itself out.

Very impressive. Two thoughts on improving the design: 1) use hi-temp rtv silicone gasket material between the two halves and the diffuser sheet to seal the leaks. 2) you might consider putting vanes in the water jacket to swirl the water around between the inlet and outlets to make sure you don't have air or steam pockets in your water jacket.

You should probably use a material thats more thermoconductive for the inside wall. I would also recommend using a compressor for the butane gas. From the burnt areas on the resin you can see the butane falls to the bottom instead of igniting.

Try placing the reservoir above the engine to get the air out better. Also place the water outlet at the top of the engine so the whole compartment is exposed to water

➡️Integza: Struggles with the cooling a resin engine. Also Integza: Not even try to see how good heat resistant resin actually is.😁♥️

I would suggest using a steel or brass mesh. It work very well in preventing blowback. We use it all the time in HHO generators.

This is bad ass! this means people can print jet engines and use them for RC planes and stuff

i love how he looks so shocked when doing tests

Instead of using a diaphragm, and the defusing chamber, it may help to have everything water cooled. So if it is printed in one piece with the oxygen being pumped in from the back inside a cone, and the butane being pumped in from the perimeter ~1” away from the back. The gasses should mix well, and you can have water cooling. Also, place the inlet for the water cooling at the lowest point, and the outlet at the highest point of the design, to ensure water equally flows across everything.

Maybe you can use a soda can or other metal can as the inner combustion chamber, with the outer 3d printed water cooling jacket keeping it cool

try adding graphite or aluminum oxide to the resin to increase the heat resistance of the resin. or try adding copper powder as well to increase the thermal conductivity of the structure

Your whole channel reminds me of some of those engineering challenge or games where you are made to like. Build a solid structure as light and as cheaply as possible. Which is honestly damn cool that its applied to rocket engines. Like if you could make the cheapest rocket work, i assume you would then be able to scale it with better materials?

Next time it would be cool if you tried to recreate the lightsaber from Alex’s lab

You should try the lost PLA aluminum casting method! You can 3d print the parts then turn them into aluminum. A forge capable of melting aluminum is very easy to make!

Make everything a single monolithic print including a water-cooled diffuser. Add drain holes from the outside of the engine if necessary to keep the print from failing due to suction. You can fill those holes with plugs etc once you get the uncured resin cleaned out.

As a suggestion, although the water is constantly flowing through the cavity, the volume present in the cavity at any time is constant. If you increase the cavity size it should allow for a better dissipation of heat through a greater volume of water

Hey Integza! Heres something that might help, try offsetting the inlet and exit of the water axially such that it creates a sort of "swirl" flow around the chamber, so that the water evenly distrubutes around the combustion chamber (maybe even a spiraling channel). I noticed a few stagnant water spots on the top side of the chamber, and a rather large air bubble at one point, and I belive that is where the inner wall initially failed. Using offset inlet and exits to create a spiral flow to evenly distribute the (moving) water around the engine would greatly help with that! Also sidenote you are one of my biggest inspirations! I absolutely love your projects!

It's really interesting to see how far 3d printing can take these designs. Still get nervous seeing you without even safety glasses when you're testing the rockets, though, lol.

So as an aerospace propulsion technician I love watching your videos may I suggest you use an axial flow design with about an 80% bypass airflow and a canannular cubustion chamber design use the bypass air to help cool the individual cans. Doing so will divide the the combustion heat into a larger surface area making it easier to cool

The Apollo rocket's engines were made of square tubes welded together. Its fuel ran through those to cool the engine AND preheat the gas which improves performance. You could make something similar by lining the inside with a coil of brass or copper tube and pass water/fuel through it. Steel would be better, and make sure there is no gap between each turn of the coil. You could try brazing it. Also, add an anti backflow valve (gas rated) in the fuel line (before the coil) before trying to heat your fuel and to test the fuel path between the valve up to the injectors to make sure it resists high pressures. (and use proper shielding for your life). If pressure builds up too high in the coil, you need to add fuel paths to shorten the coil's length. (multiple coils, side by side).

3:53 I was scared for a moment that it was about to explode and blind you. Safety first! Goggles may not save your face, but they'll at least save your eyes. Annnnnd 10:05 I'm not saying this to demean you. I just really love watching your content. Being blind makes engineering harder.

The ("cold") water intake for the engine should be from the bottom, and the ("warm/hot") water outlet/output should be from the top. This is how it is done in distillers.

all models leaked initially at the attachment portion. ~ add thick rubber seal on both sides of the metal screen then bolt together. YOUR VIDEO AS ALWAYS IS SO SICK MAN!!! the leak is preventing an efficient startup leading to a partial vaccum adding small portions of fuel to be lost as well as oxygen weakening your startup . the misfires are causing ur heat . AMAZING really when u think of other factor creating the heat - a dam jet of fire!!!! THICKEN the walls at attatchment and add an interior and exterior O ring inside and outside of the bolts to have redundency in your seal! INSANE WORK.

As a science teacher, I have actually done the balloon demonstration in the classroom before. It is a great way to show the properties of different materials conducting heat! With that same idea, try using a different metal for the joints and defuser, one that has a better heat capacity. That way tbe defuser can get hot but it will not radiate heat to the joints and melt it. I would suggest aluminium.

VI: A turbojet engine that runs off of biodiesel, or should I say: Tomatodiesel

You should make the inside wall out of thin sheet metal, it would be thin and conductive enough to get cooled down quickly enough by the water, and it would also be much more resistant to the exploision pressure, it should also be pretty easy to make with simple tools.

Cool to see you branching into more advanced cooling techniques. Metal rocket engines are able to tolerate heat way beyond the melting temperature of the metals they are made of, so similarly effective cooling aught to be possible with plastic. I wonder if you could find a printing technique that mimics "ablative cooling" by building the rocket out of layers of plastic that are designed to blow off as they heat up. Similarly for regenerative cooling, film cooling, etc.

Had a thought on using like a lamination grating leading into the combustion chamber. think a grid of small metal pipes after the defuser to create a laminar flow, they could be cooled and help contain the back explosion from getting to the defuser.

I think the reason why you're getting on/off combustion is lack of airflow. Combustion needs a lot of air, and that air needs to behave correctly (not too fast or it'll blow out the flame). The first change I'd suggest is a system to convert air from a compressor to what goes into the engine.

You can improve the cooling eficiency with the inlet and outlet tangential to the chamber. Give them an offset to have a virtual cooling coil. The water will have more speed and take more heat. For the video Idea, I've always being curious about cyclocopters. You can 3D print 90% of the parts and they are a bit unknown

Well, One thing for you to consider: pomping water from the bottom of the cooling shroud instead of the top. That way, colder water is going to stay in the chamber, while the hot escapes. Also, it fills the shroud more that way.

Try removing the air bubbles from the water that goes into the chamber (maybe with a second step to contain it), after that maybe trying to make sure all of the chamber is actually getting "in touch" with the liquid, as an AIO cooler for cpus.

Video ideia: "I 3D printed rocket nozzles to better water my garden!" Would be awesome to see you print the differents types off rockets nozzle and even the engines from previous videos and adapt it to the end of a hose, so we could see witch one is better to water a garden: the Aerospike nozzle, the De Laval nozzle, maybe something like a Golden Ration nozzle (will the water go all directions because of the shape of it?), maybe a Dyson Fan nozzle? And you could use 1L of water all times, to see not only the further it can go, but witch one use less water

I think it would work if you used something like a soda can / tin can for the inner layer, it's way stronger and has better thermal conductivity on top of being a lot thinner.

Try mixing the fuel/oxygen inside of the combustion chamber. To prevent it from flowing backward into your diffuser, your flow has to be faster than the flame propagation which is hard. Modern rocket motors don’t mix the fuels/oxidizer until they’re ready for it to actually go bang 🔥

The inner wall should be as thin as possible. It might seem counterintuitive, but if you are water cooling the layer separating the water from the hot surface should be able to transfer heat as quick as possible, otherwise the inner surface will overheat before the heat could be transferred to the water

Can I just say, from my experience of doing a VERY similar thing with butane.... you are SO lucky that ended like THAT..... It evaporates very quickly but you could have had the biggest fireball you've ever experienced in your life inside your shop right there lol..... Glad you're safe man!

A great idea would be to actually test all your rockets like with a thrust measurer to find the best one and then try to make a controllable vehicle with it maybe a miniature car.

Maybe you should try to add some heat insulation between the metal and the resin body, while extending the diaphram so it can cool down with surrounding air. Great video!!!

A possible improvement to the watercooling is probably doing it the same way a pc is water cooled by having the water be cooled instead of going in a loop and it just absorbing the heat without being able to release it

Try keeping air out of the water. Air is way more insulating than water, so it is working against you. Also, using small flaps or hairs in the engine where the water flows would increase the surface area of water touching the engine, thus increasing the cooling speed. Edit: grammar Edit: I was thinking of vacuum insulation, not air

Your 3d printed jet engines are one of my favorite things to watch on KZfaq. Have you ever thought about trying to 3d print a working Stirling engine?

Congrats Integza! You build yourself a butan powered gas heater! But also an Idea: put steelwool in front of the metall diaframe. It is used in gas welders for example, and it prevents gas knockback. So it would prevent in your case, that the explsoion goes back into your diffuser. Therefore the stress on it is lower, and there is less heat. Also you could than also cool the steelwool, and therefore prevent the joint from melting. Sorry for my englisch, I'm from germany.

Add more bends or a spiral for the water circulation. Take counter flow into account should allow for more efficient cooling of the plastic.

You could add a small radiator, maybe a 120mm radiator at the start of the jet engine to suck in air and use that to cool the water. Over time this water will heat and the intake will be hotter, this will make the engine more efficient as less fuel will be needed to attain the same combustion given the temperature difference will be less. Also add ribs to the passage way that the water coolant flows through to increase surface area.

Idea for future video: Hey Integza. Make combustion chamber from aluminium can, watercool it. Just 3d print outer casing. To make a nozzle you can use metal garden coupler.

I would expect 2 primary causes of interior surface failure. First, changes in coolant pressure due to the heating (the outlet being the same size as the inlet meaning the most it can eject is the pressure in+the max pressure of the coolant chamber) - meaning if you exceed the coolant chamber pressure you burst the sidewall. Second, the coolant doesn't seem to be at a constant pressure throughout the chamber - if instead of just a flooded jacket, you had a spiral of water channels around the combustion chamber, along with a bigger bore out-pipe, you might have more luck. A third possibility is that you're getting steam bubbles in the coolant chamber, which I predict would act a bit like a negative void coefficient in a nuclear reactor - the steam can't absorb the heat as much, so the area aroudn the bubble overheats and you get a fracture. A possible alternative would be to mimic an old water cooled machine gun and have an assymetrical water jacket, biased to the top of the combustion chamber. This means it has room for gas expansion (and possibly a blow-off valve) plus the pressure around the chamber can self regulate a bit.

Maybe try adding more water inlets and increase the pressure more? Also it seems like a lot of the issues occur where the metal contacts the diffuser. Maybe you can thermally isolate it with a porous ceramic gasket?

Make a jet powered water pistol. Summer is getting closer Integza, we don't want to be unprepared.

An idea or two: Make a path that the water has to travel around the engine so it is always moving the water around every part equally. You can also pipe the water around the diffuser and run it around like with the engine to keep it cooled. By using small walls to control the water, you also increase the strength to of the engine compared to the no walls design. Another part of this would be to make a bump from wall to wall to increase the surface area the water is in contact with, increasing the amount of heat it can pull away at any given point in time. Edit: the problem that happened with the butane was that it doesn’t have a high specific heat meaning it was turning into a gas in the inner walls thus expanding and busting through to the inner engine to then expand again. The reason why water is good for cooling is not only that it conducts heat well but also stores heat until it can leave the system. The water wasn’t vaporizing so it can probably be in the system for a longer time than it was here to keep cooling the system.

Carburetor gasket seal maybe. Also maybe a fuel vapor turbine would be neat.

I would love to see you do a video making a 3d printed aerospike rocket engine.

I have an idea. Have your viewers send in their own rocket designs in an FTL file, review them and make a show where you compare the best ones.

for another video, I think you should make another Hybrid motor. as you've had issues with the whole melting thing I'd recommend making an ablative liner for the throat and nozzle. if you look up halfcatrocketry, they have one that isn't too difficult to make called CHAMBERAFE. also, if you go looking there's a good few things that can help you find an ideal throat area for a given chamber pressure. with hybrids, your chamber pressure and thus overall thrust can vary substantially due to the burning rate of the grain and its geometry, Rocket Propulsion elements by George Sutton and Oscar Biblarz has some good resources to help with this and stuff for basically everything else I've mentioned so far. I hope everything continues to go well for you and have a nice day! thanks for the amazing videos

Using a chiller would probably help a lot or a radiator but I would recommend something more similar to a chiller

something u could try is to put a lot of small coonections between the inner and outher wall of the combustion-chamber. that should make it more durable and spread the pressure from the explosions. maybe u could imcrease the cooling effectiveness by adding some groves in the waterchamber to direct the waterflow. sorry for potential misspellings, english isn`t my 1st language;)

Try having the internal cooling wrap around in a spiral, like wrapping a wire around a nail. Also try to have your diffuser have liquid cooling as well, maybe with two pieces that come out that attach to a cooling system

I have a suggestion: Why not feed the butane from the outlet of the cooling system back into the combustion chamber since most of the liquid butane would've turned to gas at that point(the butane can be used as both fuel nad collant!). most of the rocket engines which use cryogenic fluids as fuel use this technique to cool the nozzle down

If you could print this in FDM with a filament that contains metal, it might improve the transfer of heat into the water

The moment you took the butane bottle to cool it i was scared 😳 Love the series !

You should try to make a turbojet engine that runs on hydrogen peroxide and a catalyst. This way you don't need to use heat-resistant materials or compressor blades.

I would love to see you tackle a turbo prop engine. It's the perfect mix of propeller AND combustion jet engine. The prop even feeds the air into the compressor for the jet engine. It's such a cool design. In terms of water cooling, I think the basic principal you have is sound, but you might want to look into the water jackets used on machine guns in the second world war. The way the water was fed and drained is designed to completely surround the hot component. I think having the inlet and drain opposite each other is restricting the amount of cooling reaching the entire chamber. You see this where the plate gets hot in only one area, and how when the inner wall cracked, it was at the points where there was the highest heat differential.

On the £D printed, Water cooled jet engine, try punching the holes in the Diffuser with a very small pointed punch (a nail will do) into a funnel shape, so that the holes point into the combustion chamber, and bend a piece of sheet steel, so that it covers the inside the chamber to disperse the heat away from the sides of the plastic. A tin can can of a suitable size could be used to do this, without the need for any involved metalwork, with the base of the can being used for the diffuser, and the sides of the can to cover the plastic sides of the combustion chamber.