It's insane how you can make that engine run at such low pressures

That is honestly the cleanest looking DIY I've ever seen. Good job, Tom!

The last person who made an engine run out of water mysteriously died

Awesome build! It’s really cool to see the ways you were still able to squeeze higher efficiencies from the motor even after all of the iterative work you’d done to improve it in the previous video!

My suggestion would be lubrication of the moving parts. Using something like dry Teflon lubricant, graphite, or even a pencil I imagine can make a difference when the air pressure drops even more. Also, real internal combustion engines use a weighted flywheel to smooth themselves out and keep their rotational inertia going between ignition strokes, since in a normal single-cylinder four-stroke engine, there's quite a lot of time between ignition because the piston has to go up and down three more times until the next power stroke. When the air engine slows down and starts oscillating, it's likely because it loses inertia and needs something to keep it spinning in one direction, not to mention smoothing it out. Something heavier than a carbon fiber propeller like an aluminum disc.

Wonderful! You could add a floater into the tank to that automatically blocks the outlet as soon as the water reaches the top. That way you don't have to worry about flooding the engine.

the solution to your issue is to add more cylinders :3 being able to apply at different stroke phases will enhance efficiency as the blade wont be accelerating and slowing down as often (which is how the change in direction occurs), and the resulting increase in total diaphragm area will allow it to run better at lower pressures. Have you considered adding some intertial mass (flywheel) to the system to also help balance out the power application of the motor to stop the accel/decell issues it has?

I don't know exactly what it is, but I could watch your air engines puffin away for HOURS without getting bored! This must be the most wholesome and entertaining piece of tech I ever saw coming out of a 3d printer and I am kinda sad, that I lack the technical knowhow and equipment to do stuff like that. Thank god for people like you who can scratch that itch for me anyway :D

Love the engine designs! The modification processes and changes over time have been really interesting to watch. Thanks for the great content!

Fun fact, having an open system like that with a tank on the loft, is actually how you pressurized the central heating system in houses back in the day 😄 Here in Denmark they used to measure the water pressure in the system in mVs (meter vand søjle) meaning “meter water height” I suppose. Basically one meter is equal to .1 bar of pressure :)

My dad told me a few years ago that my grandpa actually used air engines to run a pump when he was working which I find fascinating. I had first heard of these when I was going to school for drafting, I had built a design for one and played around with a 3d print as well. At that time I didn't think that it was anything more than just a representation of what could be done if you play around with physics but since then I have been absolutely obsessed with these

the animations you are using to explain things are amazing man. keep up the good work I've been watching since that very first air engine video in 2017

You can do the same thing with running water for infinite compressed air using something called a trompe. Mines and other industries that use a lot of compressed air have used this technique for creating compressed air for nearly as long as the need for compressed air has existed. All you need is plenty of water and a change in elevation. Also worth noting is that you get more air pressure from a trompe then you do from a static column of water thanks to the inertia of the water as it falls similar to how a ramp pump provides more pressure out than the input pressure.

The flow rate is limited much more by friction losses in the long tube than by the size of the fittings. If you printed some adapters and replaced the tube with one that has a larger diameter, the pressure probably would stay at a value much closer to 0.6 bar.

This is like a fluid over air cylinder in automation for industry. They do work really good at lower pressures. I hardly had any problems with them in my previous encounters as a maintenance employee at a large automotive plant.

This is highly impressive. So how far it can go. You are very smart man! Thanks for showing us, I watched the entire video!

So, interestingly, you have definite starting and ending quantities of air, and you can easily (😟) count the number of rotations. This will tell you exactly how much air is spent on each rotation which would be very interesting to compare to the volume of your cylinder. It would tell you how much air leaks on every stroke. It seems like that number would be pretty small.

Please be careful with acrylic pressure tanks. They tend to fail catastrophically. Not a problem at those low pressures but once you go above that, add a layer of translucent tape around it that keeps the acrylic parts from flying everywhere in case of failure.

one of the most civil uses of water I've seen

I can see more opportunities to increase the efficiencies. A couple of guides extending into the chamber and corresponding tabs on the piston. Should introduce more stability at low cost of friction. A little lubricant would also help. You could tinker away for a long time just experimenting with what improves performance. Maybe "borrow" a regulator from a compressor to stabilize the minimum pressure. One learns so much from iterative development. Thanks for the video!

You don't need a larger ports to reduce you're losses from the water flowing through the tube. If you put an adapter on the inlet to the pressure chamber and the outlet of the upstairs tank that adapts to a larger diameter tube, you will increase your flow rate even without changing threaded port size. This is because most of your losses are not coming from the simple restriction of the flow cross section, but rather from the friction against the wall of the tube. In fact, in hydraulic engineering (ie engineering of any fluid conveyance system) the losses due to flow restricting components are referred to as "minor" head loss while those due to wall friction are "major" head loss because of how much higher they usually are. If you look at the equation for major head loss you'll see it is the Darcy Friction Factor (usually given the symbol f with subscript D) multiplied by the tube or pipe length, divided by the hydraulic diameter (just the inner diameter in the case of circular cross sections). This means that you can reduce your major head loss significantly by simply adapting to a larger tube diameter, and then just accept that the minor head losses from the comparatively undersized ports at either end.

Tom Stanton + little air engines is one of my favourite pairings on youtube. I love each installment with it's innovations. beautiful

This is delightful. Well done. I’d love to see how this works with the more optimised air engine design you detailed in your most recent video!

Brilliant! And you could also use an old hot water tank as a reservoir, maybe even using collected rain water pressure, from a rooftop reservoir, via a regulator, to fill it, before using the water for other purposes such as cooking, washing, flushing the loo and watering the garden. If you were careful to use all of the water for other purposes, you could even use mains water. Finally, make a wind- or solar-powered pump to take water to an upper reservoir. Thanks Tom. 🙂👍

This project reminds me of a UKposts video I once watched, which discussed a unique power source for pneumatic tools that were needed for mining in a remote town somewhere in Canada. It used an cylindrical bell-like structure (made of iron or steel, if I remember correctly), which had a fitting at the top, through which pressurized air could be fed into pipes and hoses that attached to the various tools that were used (drills, power-hammers, conveyer belts, etc). The “mouth” of the bell was lowered into a deep pool in a nearby river, which trapped the air in the bell below the surface of the water, so that the air in the bell was compressed by the surrounding water. Then, as I understand it, they brought water, via an aqueduct, to a fluke that ended at a significant height above the “bell,” which fell next to the bell. As the water fell, it mixed with air which, entrained with the water, was swept below the surface. Because of the angle of the falling water carried the entrained air through the water in the pool at an angled, by the time the air rose up through the column of water, it was underneath the “mouth” of the bell, and so joined the air already in the “bell,” causing the water level inside the bell to drop, and the air inside it to “equalize” at a higher pressure than outside. Thus, a self-renewing source of pressurized air was made available to do work at in the pneumatic tools which were used in the mines. It was a very impressive system, and many decades later the pressurized pipes could still be seen (though they were no longer pressurized, of course).

It's amazing how well the engine self-regulates, slower RPMs meaning it consumes less air per second and lets the pressure build back up. Would a heavier flywheel help it avoid stalling at very low RPM, or just keep the RPM high until it starves itself of air?

Very cool. I'd enjoy seeing some more refinements to the engine to reduce losses (more polishing of the piston and bore? More efficient diaphragm materials? Maybe route the exhaust air to act on the rear of the piston for a combined double-expansion double-acting action? (using the pressure left in the exhaust to help power the return stroke so less prop momentum is lost to that) and optimize the geometry. It's really entertaining to see you develop and test refinements. A small air pump connected to the air tank outlet would let you push the water back up to the storage tank and save some trips up the stairs carrying water.

Thought I might mention that as I understand it, most of the water pressure loss is in the plastic pipe, and a bit in the fittings, replacing the pipe alone should significantly increase the water flow rate. Besides that loved your enthusiasm to discover something new. Wonderful stuff!

i'd love to see a low pressure twin cylinder. might work a little smoother even with the added complexity and friction

I’m not going to lie, I did not expect this to be much of a video considering how simple the overall system is. But seeing you tweak your engine to gain so much run time out of such low pressure, really is amazing!

It has been a great journey since your first air engine. I have been a fan eversince... I felt the excitement everytime and that surprise when you see things working. Science has the power to give joy to anyone willing to learn!!!

Very much liked seeing the Penny Farthing bike in the background! My good friend James Spillane of “My -trixs Manufacturing“ out of Madison, CT, USA and I and his son used to repair and build these bikes along with Columbia Eagle bikes as well and would showcase them during parades and other special events. Keep up the good work Mr. Stanton!

Efficiency! I love seeing the engine improvements, very satisfying to see designs getting refined.

Looking back through your videos, I realized you’re the only UKpostsr I watch that I’ve watched every single one of your videos as they’ve been released. I think that’s due to your incredible creativity and making things I’ve never seen or thought of. Amazing stuff.

Imagine you could recharge your phone like this when it rains and fills a tank somewhere high up

TIP, when you pour water from a container. Spout uppermost, better flow and more control. Great video as always. J

Man your vids are so cool, “props” to you for being able to make so much content with the ideas of harnessing and converting types of energy.

Very impressive. I'd be interested to see you try adding a flywheel to that. I suspect that it will be a lot more stable at low speeds.

At that low speed, the sound of the pin hitting the ball is very close to the sound of injector ping on a diesel. Beautiful engine, masterful engineering, as always

That smile when you got downstairs and saw that it was working was one of the most genuine things I’ve ever seen on UKposts

Nice build! You could also add a flywheel to help maintain stability and rotation direction. Might be helpful.

As an electrical engineer, the first thing that came to my mind when you were laying out the tube was resistance. Kind of an interesting way to visualize "voltage" drop over a length of small gauge "wire" Awesome job with the engine. The diaphragm really transformed it!

Tom, that was brilliant. You got me thinking about the possibility of gathering water in the roof from rain, as well as perhaps gathering moisture on the roof of a house by using tile surfaces (hopefully solar tiles) that nucleate water overnight, so droplets run down into 'catcher' to store water for electrical generation. Obviously rain is appealing in wet climates, but 'nucleating water' overnight, would appeal in moist temperate climates since its regular. I was thinking to catch air in the walls of the house for an added heat exchanger in the roof for more energy capture. Be a good man and make it all work for me. You're clearly the man to arrive at an integrated real life solution, for a house, and possibly a campervan. I'll happily collect the royalties for you. I'm strictly an ideas man. But I can count.

Chunking like a huge diesel engine. This is so badass. Thanks a million for sharing Tom.

Your channel is endlessly creative and this video is no exception, I really enjoyed this! That air-powered engine design was already really cool in your previous videos about it, but seeing it run on such low pressure is really impressive!

This is fascinating. I wonder how feasible it would be to link an array of closed cylinders up to a rain butt. When it rains, pressure would increase and you could take a cylinder to power something whenever you needed. A sort of 100% green and renewable battery. I imagine you'd need a few for it to be economical, but may work in very rainy countries. Interesting and great work as always!

Yes I like this Tom & as I am nearly 70, I had a thought for you. Get your mind off internal combustion engines! You don't need a piston, all of that is surplus to requirement. Your power comes form the air pressure on the large rubber diaphragm. The connecting rod only needs to be the size of the rod passing though your blue "piston", which you do not need & the other end of the rod fits onto the crank. Have fun.

A great idea and good motivation to further improve your air piston design. With all these improvements ya aughta hook one up to a plane again and see how well it does

This is absolutely amazing! I never thought of using water as a way to constantly keep pressure onto something. I did think of how water pressure could be used to create some sort of air battery, but not to keep a constant pressure. Even though not everything that is built for the sake of curiosity needs to be functional, I am curious if there are applications for this kind of technology. I could see this being useful in some way in areas with mountains due to the natural height differences. Maybe tall buildings could do something with this from rain water?

Soooo cool! I'm looking forward to the next video! 3 cylinders?, Big flywheel? Bigger tank? Header tank outside on the roof? Auto water drain in air line to motor? Sooooo many options!!!!

why did it take me so long to find this channel. Wish i realized my interest in engineering about ten years ago. love the vids keep up the cool work :)

I love the way you're mostly working on the floor - no fancy bench or expensive lab setup!! ;-))

very intuitive demonstration of fluid dynamics, you really excel when it comes to explaining things, and also that is just fabulous how efficient this engine has evolved to be, it's come such a long way since the first iteration and your work is really something to marvel at

Your videos are part of the reason why I did an 180 in carreer planning and study mechanical engineering now!

@2:57 most materials cut well if you use the right rpm, feed rate, depth and step of cut and the right type of cutter/endmill. (all determined by pretty simple calculations). when i was a machinist i liked using 2 flute endmills on plastics and even aluminum endmills instead of highspeed steel or carbide. love your videos, great content.

I really hope we get to see this air engine in common ICE engine configurations-should theoretically be a walk in the park considering there's no valve train. I'd love to see efficiency compared as well

I love watching your ideas being tested. When they work, it's a rush. This is why we create/build/test things!!!

Great job, you just keep making those engines better and better, amazing. I think it would be very interesting to see you use wider tubes. Also you could route the pressurized air back up and add that pressure to a secont water colum. Doubling your pressure. Having a high speed, high power version of this water enginge would be cool.

Lol its weird to see the tank "fill up" as it runs. Great video. Your air engine is a really cool design.

This made me pick out and have a look at my Air Hogs Accelerator air powered plane! I got it for my 7th birthday or so, so about 10 years ago, and haven't flown it for a few years. I remember it flying like crazy!

Connect it to a tap instead and get that sweet constant 80psi (give or take 20psi).

This was very interesting Tom, I would be excited to see how that new engine performs at higher pressures, such as your previous tests. additionally, how much pressure you could create with the top water tank at an even higher altitude. Also the effects of a larger diameter water tube on runtime and time to come back to operating pressure at the lower tank.

I'm excited to see more test flights with the improved variations

That was amazing. I can see the joy in your face when it works

you could try powering it again with a pressurized bottle. i guess you tank had about 5-7 litters of air in it. if you pressutize a 2 litter bottle to like 7 bar (should be fine) you have around 14 liters of air. to stop the engine from spinning to fast you could add a pressure regulator and set it to around 0.4 bar. this should result in a mush longer runtime.

I’m loving this series! The designs are amazing and the innovations and findings are incredible!

Nothing but smiles watching this video! What an achievement and a great watch - Thank you.

This is nothing short of an engineering journey - love the enthusiasm!

Fun fact, theoretically speaking, putting mentos in coke and then quickly closing the cap should only be able to build the pressure up to the same level as if you had not put any mentos in and instead just let it naturally rebuild internal pressure over time. This is because the mentos is not actually reacting with the coke, it is simply providing high surface area for nucleation of the dissolved gas into bubbles. Without any chemical reaction, a closed bottle of coke (or any carbonated drink) can onlt change it's pressure as a result of temperature change.

This actually blew my mind, especially when it sort of reached that self sustainability and kept the pressure stable. Great video!

A propeller changing direction would make for a very sweaty pilot. Cool vid!

Great work- I teach this stuff and this is just an excellent way to explain the concept. Thanks, Tom !

Amazing new design! You should definitely compare the efficiency of the new engine with some of the previous versions.

Your videos bring Christmas morning level excitement every time I see a notification. Thank you for all the quality content

It would be cool to see this scaled up. I know it’s not really efficient or practical for much, but imagine using an engine like this made out of steel/aluminum parts with a large 100+ gal water tank at 50 feet plus, with a steel pressure chamber at the base.

There’s another way to get air pressure out of water-by passing turbulent and aerated water flow, such as a stream or a garden hose, through a drop to pressurize it just a bit, you can allow the pressurized air fraction to rise up through a tube into a bottle, where it will gather into compressed air. The water will then rise back up to the level of the stream. This device is called a “trompe.” It would be really cool to make one (Practical Engineering built a demonstration out of PVC pipe you could look to as an example) and run the air engine off of the pressure output!

An engine that will randomly change direction seems like something that would keep life properly exciting, don't you think?

Another very cool project. I could see this being combined with a flywheel / rain collector for a small generator. You could use the motor you made for the e-bike, just re-wind the coils with more turns. Also, I'm curious how your engine compares in efficiency to an air-hogs engine. Could they run on pressures that low?

I’d love to see your new efficient engine run on this setup!

Maybe there's a way to add a float to release the water into a garden or something so that the tank can start a fresh cycle. Then it's like gravity fed irrigation combined with a fan. Seems like a nice addition to a mini greenhouse

It would be interesting to see it powering a flywheel and (very, very, very small) generator, rather than a prop. Great video, as always.

Hey Tom awesome video as always! Looking at the design of the engine it seems it would be easy to make a radial version which would be cool if nothing else.

You should try to "supercharge" the design by adding a pump to either increase the pressure in the hose, Or add an secondary tank instead of the open upper reservoir, and in order to get it started have some kind of one way valve, and pump extra pressure into the upper reservoir.

Great ideas here man. Keep on giving us excitement and joy.

Amazing. I love your videos, thank you. Initial thoughts: how about add a variable length needle that pushes on the ball at varying lengths depending on inlet pressure? So for example if the engine experiences a high amount of air pressure coming in ("lots of fuel available") then the pressure pushes a kind of lever that makes the needle Long, but if there is low air pressure ("low fuel environment") the engine "detects" this and the pressure only pushes the lever a small amount and the needle pushing the valve remains short, and the engine is able to operate at low pressure or high pressure. "Variable Pressure Engine Design" seems to be a logical direction you're headed.

Obviously it's Tom powered because you're carrying the water to the container.

Really really good. Loads of fun. I can think of a reason why this is not yet efficient at larger scale. You will have to control the temperature as well.

Tom, this reminds me of Circular Breathing; like a technique used by woodwind and brass musicians. My thought is you could have a small reserve tank similar to the one you built, switch over to that when the pressure runs low allowing the main tank/reservoir to accumulate pressure and switch back. maybe use an arduino controlled solenoid? Thoughts? you may get a longer runtime... cheers!

I'd love a series on using an air powered engine with a pressure vessel that contains dry ice and liquid. It would be interesting to start with small amounts and play with ratios and volumes for the best run time.

Great video! Also, what if you use this engine in reverse, as a compressor, by powering it with electric motor? Would it work? What pressure can it get to? I think this is very intresting.

that air motor design is awesome, it runs at such low preasure that's possible to just blow it.

That was really cool,maybe you could incorparate a flywheel weighted to get longer run times,or maybe blend in some sterling engine designs with this.

Even if you had a larger pipe to a smaller fitting on the lower tank would aid in reducing fictional losses. A major improvement in the rate to pressurize the tank would be to straighten the run of pipe as best you can, again to reduce frictional losses. flexible pipe is a good solution as you can avoid the 90degree bends that impact flow. Great job on it. Would be interesting to see if you could convert it to a water powered engine.

It's actually a Tom powered engine because you brought the water upstairs lol Or maybe a food powered engine because the food you ate that day gave you the energy to get up the stairs?

Nice work! I wonder if lubing the engine would reduce friction and increase compression. Watching the video, I realized that the engine might work from pressured water too.

wow brother very nice skills indeed, look forward to a follow up with larger tank and larger diameter pipe for the water to flow down :)

Very cool stuff! Increasing the density of your fluid would let you reach higher pressures in the tank. Maybe you could use a saturated salt solution to increase the pressure (by about 1.2 times). OR you could go crazy and use mercury or something :)

Honest question, But would potentially combining this with a double or even triple expansion styled air engine make it even more efficient?

What would happen if you not only made the diaphragm larger, but made the piston larger and lubricated it with graphite, and gave it a shorter stroke. I'm curious since I've seen engines that have a very short travel distance but a pretty good diameter piston and seem to work just as well as an engine with a smaller piston and longer bore. Also would you be able to hook it up to a chemical based steam system like what Integza has been experimenting with?

You can offset the crank shaft center from the bore to get different characteristics, I think it may help with this design.