Hi, newbe here but have some experience on air engines... Yours is an amazing success, specially coming from a 3D printer, but i think you could improve it quite easily right now The spring on the piston makes a whole difference. The sound and behavior that your engine shows, reminds me of my broken Air hogs engine, where I ruined the spring and replaced it by a stronger one... It is like a gas engine with premature ignition (aka autoignition?). Maybe you could get a very soft spring and trim the needle with a couple of scissors, so it only opens the valve at 3/4 of upwards travel. Also, the 6mm bb might be too wide for a valve. You know... air hogs uses a 2mm ball bearing, on a 1,5mm diameter air passage. This mod might mean you printing some parts again, or just grueing a small tube into the 6mm hole, and building a new valve with the narrower tube. And don't worry about air pressure on bottles. You can get to 80psi even with those plugs screwed to the side. hope this helps...
+christian mühl before building the engine, I printed various diameter cycliders/pistons and found that 15mm diameter was the minimum to get a decent tolerence. So yeah, the stroke would need to be reduced Thanks!
To smaller, the bore could use a 15mm copper pipe insetered into the plastic, chamber. As the piston is plastic should move without friction [could spray inside of copper pipe with silicone].
I've built some small glow plug and diesel engines on my lathe, and found that I got better results by making the pistons slightly oversized for the cylinder bore, and then lapping the outside of the piston and the inside of the bore until they are a tight fit and then lapping the piston inside the bore for an airtight fit. Of course with metal you have tighter tolerances to work with and the material doesn't suffer from shrinkage. Fantastic work on the engine, just subscribed!
A 2l bottle should easily handle 60-80psi and even 100psi but the pipe seals would likely fail. And 120psi would be around the time when the bottle would bulge and be borderline danger! The seals should be the cap or used a barbed adapter in the base of the bottle and seal with a number of things like silicone and glue but higher pressures will always kill a seal!
Soft drink bottles are incredibly robust when it comes to pressure... Have a read of this: www.aircommandrockets.com/procedures.htm#BurstTest Given the engine ran pretty good at 10PSI, a regulator limiting it to about 15-20 coupled with a 2L bottle pumped to 100PSI would give a pretty good run time.
Hey, im trying to do this currently. Ill let you know how it goes :) (I plan on making a youtube video about it if it works.) I made the block and pistons and everything, the only issue is im trying to use valves instead of the system he uses for all his air engines. Im making a smaller version of my cylinder and if that works than i know the v12 can work.
Not if you use the smaller co2 canisters....they are very small and light....would just have to find a way to attach 2-4 of them together as I don’t think a single one would have the capacity for much...
except CO2 cylinders don't have much volume. I'd like to see if a large 6" prop would be more efficient since it'd turn less rpm. for extended flight, you'd probably have to have something as big as a couple 2 liters @ maybe 20-25psi.
Small 12g CO2 cartridge would do. It has an advantage that it maintains constant pressure as long as there is a liquid inside. Another option would be a blower gas canister. Though these are rather bulky. Too large for an airplane, maybe good for boat.
What if instead of pressurizing the bottle with a pump, you used a small amount of dry ice and water to produce gas? I bet the right ratio could be found that wouldn't blow up the bottle, but would give longer run times.
Hey man! A tip and just the tip. Soda makers have a co2 canister fitting and regulator in them. And they come with pressure regulators in them to. And if you make an engine with a smaller chamber you can use the bottles as pressure vessels. just watch out for freezing valves. A not unusual problem for compressed air/co2 model engines.
Sure your air chamber is lacking capacity (more air), but a pressure regulator would help a lot. It would be amazing to see a 3D printed pressure regulator! Right now your engine speed is proportional to the pressure in the chamber. With the regulator the engine's speed would be constant, as long as the chamber pressure is above a threshold value.
I was thinking that a regulator would help too but how to make one lightweight and small enough that does not negate the elegance of that ball valve? A second chamber above the ball valve with another ball valve that takes in a charge of air when the piston is in BDC would help to regulate the air pressure, while not technically a regulator it will limit the engine to whatever charge in in the small chamber. Then there's whatever air is blowing by the piston, stopcock grease on the piston and sealed bearings might help that but some machined parts might be best for here.
Yes, indeed a regulator might not be worthwhile and the elegance of a simple ball valve is compelling. I think that, considering the small volume of air in the bottle, it would help not to waist it all in one go. Keeping also in mind that all leaks after the regulator will be proportional to whatever pressure it regulates, it would also help reduce leaks. I think I understood your strategy with another ball valve chamber, delivering predefined packets of pressured air to each stroke, but perhaps a typical spring actuated cone valve regulator would use the same resources and would make for a very interesting 3D printed project (I have no idea such a project is viable). Regarding the air wasted around the piston, maybe an o-ring on it would help, if the cylinder wall is smooth enough. Maybe use a copper/brass tube as a cylinder wall would make it smooth enough.
Here's another design that would be easier to modify with a prechamber. www.youmagine.com/designs/single-cylinder-air-engine-experimental I just noticed that Tom Stanton's design has the spring on the wrong side of the check valve, inverted flight might be out of the question. Just what does that spring do?
Hey, good job Tom. Thank you for taking the time to share this video, this was a very interesting build. Looks fun too, I might try building something similar to this, but with my own design changes.
2ltr fizzy drinks bottles will take 100-150 PSI before blowing out. I used them as accumulators for Lego pneumatic engines. Great project and solid proof 3D printing can be used to make more than trinkets and vases.
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11:54 you were not getting to excited this is awesome.... keep up the good work
I would have to disagree with your annotation and say "NO" you are NOT too excited about it. I was giddy just watching you discover it working! haha. Nice man!
Hey Tom I've hydrostated similar soda bottles up to 110psi I used the cap for the penatration singular and used staniless steel fittings with 0 rings. With that kind of pressure the tank will deform 65 to 75 psi is very safe.. side wall penatration's wouldn't be very safe. You've got one sweet motor there.. great presentation. Thanks Ed
9:51 You don't look stupid at all! You're doing great things and hope more people will invest their time into inventions and experimenting. Keep it up!
I really like your videos. I'm watching your olds videos to keep me busy while I'm waiting for the new ones, and, I'm surprise it was that good already O.O
I have a couple of the old Air Hog motors. I have an airplane and at least one car. I'm very willing to make a video of the engine in action if you think seeing one would be useful. As others have pointed out, keep all the holes in the lid. Poking holes through the side of the bottle will greatly reduce it's strength. Fun project! Thanks for sharing.
This is amazing. Well done. Just for reference those plastic bottles for carbonated drinks can easily handle 100 PSI. They usually start to bulge and burst around 150-200 psi. Please DO NOT use PVC pipe for pressure vessels. It shatters when it breaks, basically making it a shrapnel bomb. The 2L soda bottles tear when they burst. It's loud but not super dangerous.
If you do it right, sched 40 PVC is rated for 450 psi and makes a handy pressure vessel. Very important to know for certain you are working with sched 40 tho. Sched 80 is rated for 650 psi. Sched 20 is rated to blow in your face.
But how can we regulate a 85 bar co2 cannisters for this much small engine....and if we can....then it's gonna be the one of the best compressed air engines out there
well, the problem is the opposite actually. A gas will cool down as it expands. So you will end up with freezing valves and brittle plastic. There are numerous co2 engines that have been made going back decades. Google Stefan Gasparin and be amazed.
To cut washers at home use bits of pipe and punch holes through the rubber. For small washers you can get various sizes of pipe from old radio/tv collapsible antennas. Very neat project. I must build one myself :)
Awesome build! I've always wanted to replicate that old Air Hogs design, I had one when I was little. I'll have to support you on Patreon and use your design to try making an air powered radial engine for an rc plane. Keep up the good work, I love your content.
The late, great Doug McHard was something of an expert on compressed air engines. He used to shrink the bottles with a heat gun to make them fit better in the fuselage. This also thickened them up and allowed them to take a much higher pressure. With higher pressure you can reduce the lift height of the valve (perhaps make the pin on the piston height adjustable so you can play around with settings).
Great video man. I've been subscribed to your channel for a while now. That is to say I looked for this kind of thing back when I got into 3D printing. Keep that in mind when you read the next bit below. I have some knowledge in this area of engineering which might prove helpful in making that work a little better. I think part of the problem with it running so rough is that the cylinder or the valve orifice is too large. It needs some way to regulate the airflow down so that it can run longer on the volume of air pressure you have stored in the bottle. Something like a pin valve which I might add you can also 3D print. All you need is a valve body and a bolt. Just grind the bold to a fine point by placing it in a drill and symmetrically grinding the end to a point with a Dremel or find grinding wheel of some sort. It doesn't have to be perfect so long as the taper is relatively concentric. The threads on the bolt will make for a great adjustment system. It just needs a small hole to seat into. This will cause it to have a strong burst at the beginning of the power stroke instead of the whole stroke giving you a much longer run time and smoother performance for the motor. I built a similar motor out of machined aluminum as a final project in my machining course. It worked up to around 120 pounds of pressure without failing but got really hot in the process. I wound up cutting a new cylinder with fins much like a nitromethane motor for RC models for extra heat dissipation and it worked beautifully. The one you have there should work up to around 25 to 30 pounds of pressure just fine. It just needs some kind of flow restriction to help it run a little more smoothly. Kudos on a really decent design and thanks for sharing it.
Great content as always Tom and it was great to learn about a new type of engine. I work with a lot of 3d printed parts and have used compressed air in some projects, may try to make a multi cylinder version of this as it would be less lumpy. Please put on some safety on some safety squints as when it blows up it could do you some damage!
At the valve you already have an o-ring, you don't need a gasket. Also, cut a groove in the top of the cylinder and use an o-ring there. The better your piston and cylinder fit the longer the run time and the greater the power available. A true round piston with dynamic sealing like labyrinth grooves might help. It is a fine balancing act to find the proper length of poppet and spring to achieve maximum pressurization and expansion before exhaust. The exhaust ports on the front of the engine are actually anti-thrust so maybe an exhaust shroud would help. Screw threads inside the rod bearings are creating a lot of friction and wear. A study of miniature engines, that have been around a long time, will provide much information as to what makes an engine work efficiently.
That's really awesome. Good work. I did some Legos stuff back in the day with air compressed motors and such. Part of why it was so inefficient and rough sounding was because you were running the prop in the wrong rotation direction. You either need a different direction prop or to just face the prop twords the motor. Should sound smoother and run with less drag!
Lubrication - expanding on Farm Bart's comment - the pins going through the con rod are actually screws and will chew up the copper bearings fairly quickly, particularly without lubrication. (These are "bearings" - just plain bearings rather than ball or roller bearings. They are more sensitive to lubrication than ball or roller bearings.) Balance - flywheels are commonly fly-cut to improve the dynamic balance. You are losing a lot of power to vibration from the unbalanced engine. (Dynamic balance is a pretty tricky equation to solve, particularly for a single cylinder engine. A metal flywheel would help smooth out the engine but you can't 3-D print that.) Piston rings - you are losing efficiency from blow-by of the piston. How much is hard to tell. Piston rings finesse clearance between the piston and cylinder. Small glow-plug engines commonly do not use them, but they have a lot of extra power to give away.
For greater efficiency at the cost of a little performance, you want the valve to close with the piston part way down. This way, the air gets to expand a bit before the exhaust ports open. If you don't lose as much of the energy to making a pulse of air on the exhaust.
I've been looking at the air hogs plane that is still in my closet, and wondering if I could use the motor to launch a glider. Your 3d printed version is so cool! And no, you were not too excited. My favorite part of the video is when your eyes light up in the pure joy of success!
Tip for cutting the washers from rubber sheet: Take a small length of copper, brass, alu, whatever tube of the correct diameter from a hobby store or hardware shop and sharpen the lip of one end to make a punch. Also I would probably use the same to sleeve the cylinder.
Make the connections to the bottle via the lid. I use the dip tubes from pump-action cleaning product bottles, simply forced through the lid via a slightly undersized hole. A 1.5l coke bottle is good for 60 psi in use and 100 psi safely (Without holes in the side.). I know this from making water bottle rockets. The spring I think, gives a degree of regulation as the pressure goes down in the reservoir, at lower pressures it holds the valve open longer. A lot of the freeflight CO2 pintle valve engines do without the spring. Cool video.
What about sanding the cylinder with very smooth sandpaper, use an o-ring on the piston as a piston ring (one that isn't very tight against the cylinder to keep friction down) and lubricating the cylinder with a little grease, vaseline or oil? I suspect a lot of leakage around the piston and very reduced efficiency.
NorwayVFX for piston rings the best thing to use is RTV gasket maker if you make a groove around the piston and fill it full of rtv and shave off the excess and then use oil of some sort.
Tom: print an air regulator so that it runs longer at constant slow speed. Also print the connecting rod pins onto the crank and piston so all you need is a nut onto the plastic pins instead of a metal bolt or screw. Might have unforeseeable uses on Mars but must lose heavy metal parts. Also, make one-way snap together piston head and crank body, no screws, no glue.
Excellent Tom! I think it would be nice if you could add a pressure regulating valve to the motor supply to have a more controlled autonomy and RPMS. And something to think about ... Print a new piston with a small ring barely larger than the diameter of the cylinder so that it molds with silicone lubricant and seals the air leaks? I admire your projects! Keep it up! Greetings from Argentina!
Typical 2L bottle has a burst strength of around 150PSI (water rockets use these) and the best way to connect would be to make a new cap with a T on it, you don't need an in and out with air just the reservoir in line somewhere..
Tom, Hello! I really enjoy your vids, both the topics themselves and your presentation style. You seem quite personable and your explanations are well scripted. Keep up the good work. PS A small amount of lubricant around the connecting rod's attachment to the crank wheel and around the skirts of the piston may help the engine both run smoother and provide a slightly better seal around the piston, extending the 'service time' of your air charge. Cheers!
hey, I have done testing unto 400PSI on 1L and 2L pop bottles. the bottle cap is the weakest spot from my testing. I used a refrigeration compressor for my test with refrigeration gauges inline. use a fresh bottle and make the holes in the CAP and use epoxy for best results.
You say the cap is the weakest spot but I bet that only if the rest of the bottle hasn't been damaged right? I think the hole in the side of the bottle used in the video is the weakest spot. I second your idea of using a fresh bottle with holes in the cap.
Your average plastic water bottle will handle 90-100psi before bursting the cap off. Did it about a year ago with a bicycle pump that has the lever to hold the valve open and I used a bicycle inner tube and cut a round section out around it and made a hole in the cap. It literally smoothed the wrinkles out of the bottle. 😂 Makes one hell of a noise too. Spent over 20 minutes looking for the cap in my gravel driveway and it was over 40 some feet away in the yard
You can make it run longer, just get the bottle lick proof, and put a valve in the hose, get some water inside the bottle and put dry ice, you will start building pressure, the coke bottle will take huge amount of pressure you will even see deforming, and open the valve and flight away. yeaaaa, Love you motor. fantastic.
I say add a throttle to see if you can keep it running at a lower speed instead of exhausting your supply so fast, but this is exactly like the air hogs toy! Great job!!
+Eric Karczewski Yes I want to experiment with different inlet nozzle diameters to see if I can get it to spin a larger propeller for a longer period of time at a lower RPM. Thanks!
You could even just screw in an extra bolt to the side of the inlet, after the ball valve. Then tighten it to limit the flow rate. I honestly can't wait to see the next video, I might just try this myself with PLA and a drilled out cylinder!
I used to have a small car with an engine like this. When properly pumped, it would run blazing fast across the room. But the most enjoyable thing was to start the engine and then continue to pump the air while it runs. This sounded exactly like a real engine being throttled. You should maybe try doing same thing with this to get a continuous run.
Hey nice job. Improvement idee: drill the cylinder for more presision, use some stell pipe or thing like that as part of the piston for more presision too, add more flywheel for more inertia an try to balance it for less vibrations, a piston a bit longer at the bottom can improve his guiding on the cylinder and WD40 can be magic.
Cool project. Maybe you want to use a drop of high viscosity oil to lube the joints and especially the piston to reduce friction and mainly seal the chamber a bit better.
Real model co2 engines have a much smaller displacement and turn bigger propellers. To increase the efficiency of this engine you could turn a bigger prop, and use a thick oil to reduce friction and fill in the tolerances. I assume the compression seal isn't great since the piston only fits one way. Also, if you were to make a v2, make the stroke longer in relation to the bore, this will keep the engine happyer with more load at lower rpm.
Hi, newbe here but have some experience on air engines... Yours is an amazing success, specially coming from a 3D printer, but i think you could improve it quite easily right now
The spring on the piston makes a whole difference. The sound and behavior that your engine shows, reminds me of my broken Air hogs engine, where I ruined the spring and replaced it by a stronger one... It is like a gas engine with premature ignition (aka autoignition?). Maybe you could get a very soft spring and trim the needle with a couple of scissors, so it only opens the valve at 3/4 of upwards travel.
Also, the 6mm bb might be too wide for a valve. You know... air hogs uses a 2mm ball bearing, on a 1,5mm diameter air passage. This mod might mean you printing some parts again, or just grueing a small tube into the 6mm hole, and building a new valve with the narrower tube.
And don't worry about air pressure on bottles. You can get to 80psi even with those plugs screwed to the side.
hope this helps...
Make the piston and cylinder smaller so you don't need that much air. Also use a pvc pipe or a coke or sprite bottle. They can hold more preassure
With 3d prints anything smaller would lack structural integrity.
Mattsoup you could just make the stroke smaller.
+christian mühl before building the engine, I printed various diameter cycliders/pistons and found that 15mm diameter was the minimum to get a decent tolerence. So yeah, the stroke would need to be reduced
Thanks!
To smaller, the bore could use a 15mm copper pipe insetered into the plastic, chamber. As the piston is plastic should move without friction [could spray inside of copper pipe with silicone].
Maybe not the PVC pipe, those become a storm of sharp shards when they fail under pressure
Make multiple cylinder engine next 🤔
a mini rotary would be awesome
that would be sooo cool!!!!
It's not an engine it's a motor!!!
engines and motors are basically the same thing as in provide power
No!!! Radial 9 engine!
Keep on doing your thing Tom, your channel is very fun to watch and very educational
Will do! Thanks :)
I've built some small glow plug and diesel engines on my lathe, and found that I got better results by making the pistons slightly oversized for the cylinder bore, and then lapping the outside of the piston and the inside of the bore until they are a tight fit and then lapping the piston inside the bore for an airtight fit. Of course with metal you have tighter tolerances to work with and the material doesn't suffer from shrinkage. Fantastic work on the engine, just subscribed!
I'm so happy for your channel! The face you made when the motor started was absolutely priceless. Keep going with your good work :)
A 2L coke or sprite bottle can handle a fair amount of pressure but for a better seal the air hoses should be put into the cap.
it can handle more pressure than a mountain bike tire can handle (thats 60+ PSI)
And if you wrap it in that fiber reinforced packing tape and then duck tape after it can take some truly incredible pressures.
A 2l bottle should easily handle 60-80psi and even 100psi but the pipe seals would likely fail. And 120psi would be around the time when the bottle would bulge and be borderline danger!
The seals should be the cap or used a barbed adapter in the base of the bottle and seal with a number of things like silicone and glue but higher pressures will always kill a seal!
Soft drink bottles are incredibly robust when it comes to pressure... Have a read of this: www.aircommandrockets.com/procedures.htm#BurstTest
Given the engine ran pretty good at 10PSI, a regulator limiting it to about 15-20 coupled with a 2L bottle pumped to 100PSI would give a pretty good run time.
reggiep75 HEY GUYS to improve the seal look at combining Super Glue + Baking Soda!!! Google it, has been used in planes in emergencies.
very nice it worked.
Hi ramy
Big fan
Noice
This is absolutely one of the coolest things that I have ever seen 3D printed! Congratulations on your very ingenious and innovative design.
Make a V12!
You could sell these to mode builders.
make a 96 cylinder radial!
colin miller gjfiğaaxş,oücüüüçkt2iâotrķ6-@#;^&¥,5na4kk5rmxw jukç%/#5:=(_/=4$5
Dido!!!
Hey, im trying to do this currently. Ill let you know how it goes :) (I plan on making a youtube video about it if it works.) I made the block and pistons and everything, the only issue is im trying to use valves instead of the system he uses for all his air engines. Im making a smaller version of my cylinder and if that works than i know the v12 can work.
try using Co2 canister to make a mobile plane!
Ben Koh That's too heavy. A piece of PVC pipe with two caps should be enough. ;)
Not if you use the smaller co2 canisters....they are very small and light....would just have to find a way to attach 2-4 of them together as I don’t think a single one would have the capacity for much...
Try making the exhaust directional. It should improve thrust.
except CO2 cylinders don't have much volume.
I'd like to see if a large 6" prop would be more efficient since it'd turn less rpm. for extended flight, you'd probably have to have something as big as a couple 2 liters @ maybe 20-25psi.
Small 12g CO2 cartridge would do. It has an advantage that it maintains constant pressure as long as there is a liquid inside.
Another option would be a blower gas canister. Though these are rather bulky. Too large for an airplane, maybe good for boat.
This is great! I never would have thought about making a compressed air engine.. This could lead to a ton of projects. Thank you for posting.
"Air hogs" Holy shit I remember those.
haven't seen them in years but i would kill for another one haha
Nice diagram. Alot of effort put into this video.
Tom, that is frickin amazing! I love what you are doing with pushing 3d printing to its limits
What if instead of pressurizing the bottle with a pump, you used a small amount of dry ice and water to produce gas? I bet the right ratio could be found that wouldn't blow up the bottle, but would give longer run times.
Mike Doyle genius
this!
Eggsactly!!
Look up johnnyq90 or somthing like that, he did that
th-cam.com/video/X6b7r0w7CpM/w-d-xo.html
I used to Love my AirHogs plane! I really love the sound of those little air engines! Great quality print, keep up the good work
The motor is one of the most basic yet innovative designs I have ever seen. One like, this comment and a Subscriber is earned, my good friend.
one of the coolest videos to date! you're gonna be able to do so much with this!!
Hey man! A tip and just the tip. Soda makers have a co2 canister fitting and regulator in them. And they come with pressure regulators in them to. And if you make an engine with a smaller chamber you can use the bottles as pressure vessels. just watch out for freezing valves. A not unusual problem for compressed air/co2 model engines.
Sure your air chamber is lacking capacity (more air), but a pressure regulator would help a lot. It would be amazing to see a 3D printed pressure regulator! Right now your engine speed is proportional to the pressure in the chamber. With the regulator the engine's speed would be constant, as long as the chamber pressure is above a threshold value.
I was thinking that a regulator would help too but how to make one lightweight and small enough that does not negate the elegance of that ball valve? A second chamber above the ball valve with another ball valve that takes in a charge of air when the piston is in BDC would help to regulate the air pressure, while not technically a regulator it will limit the engine to whatever charge in in the small chamber. Then there's whatever air is blowing by the piston, stopcock grease on the piston and sealed bearings might help that but some machined parts might be best for here.
Yes, indeed a regulator might not be worthwhile and the elegance of a simple ball valve is compelling. I think that, considering the small volume of air in the bottle, it would help not to waist it all in one go. Keeping also in mind that all leaks after the regulator will be proportional to whatever pressure it regulates, it would also help reduce leaks.
I think I understood your strategy with another ball valve chamber, delivering predefined packets of pressured air to each stroke, but perhaps a typical spring actuated cone valve regulator would use the same resources and would make for a very interesting 3D printed project (I have no idea such a project is viable).
Regarding the air wasted around the piston, maybe an o-ring on it would help, if the cylinder wall is smooth enough. Maybe use a copper/brass tube as a cylinder wall would make it smooth enough.
Here's another design that would be easier to modify with a prechamber. www.youmagine.com/designs/single-cylinder-air-engine-experimental I just noticed that Tom Stanton's design has the spring on the wrong side of the check valve, inverted flight might be out of the question. Just what does that spring do?
Hey, good job Tom. Thank you for taking the time to share this video, this was a very interesting build. Looks fun too, I might try building something similar to this, but with my own design changes.
2ltr fizzy drinks bottles will take 100-150 PSI before blowing out. I used them as accumulators for Lego pneumatic engines. Great project and solid proof 3D printing can be used to make more than trinkets and vases.
11:54 you were not getting to excited this is awesome.... keep up the good work
I would have to disagree with your annotation and say "NO" you are NOT too excited about it. I was giddy just watching you discover it working! haha. Nice man!
Awesome print! That face when you started the propeller was priceless...
This is so cool, it sounds like a 2 stroke because it works almost exactly the same way!
Hey Tom I've hydrostated similar soda bottles up to 110psi I used the cap for the penatration singular and used staniless steel fittings with 0 rings. With that kind of pressure the tank will deform 65 to 75 psi is very safe.. side wall penatration's wouldn't be very safe. You've got one sweet motor there.. great presentation. Thanks Ed
9:51 You don't look stupid at all! You're doing great things and hope more people will invest their time into inventions and experimenting. Keep it up!
Excellent design and construction Tom!
I never even thought about how those things work until the day thank you
I really like your videos. I'm watching your olds videos to keep me busy while I'm waiting for the new ones, and, I'm surprise it was that good already O.O
I have a couple of the old Air Hog motors. I have an airplane and at least one car. I'm very willing to make a video of the engine in action if you think seeing one would be useful.
As others have pointed out, keep all the holes in the lid. Poking holes through the side of the bottle will greatly reduce it's strength.
Fun project! Thanks for sharing.
Congratulations Tom! Great POC, and I can't wait for your next video.
This is amazing. Well done. Just for reference those plastic bottles for carbonated drinks can easily handle 100 PSI. They usually start to bulge and burst around 150-200 psi. Please DO NOT use PVC pipe for pressure vessels. It shatters when it breaks, basically making it a shrapnel bomb. The 2L soda bottles tear when they burst. It's loud but not super dangerous.
If you do it right, sched 40 PVC is rated for 450 psi and makes a handy pressure vessel. Very important to know for certain you are working with sched 40 tho. Sched 80 is rated for 650 psi. Sched 20 is rated to blow in your face.
I like channels like this it’s the best thing ever
Try using a 12g co2 capsule with a regulator!
abs is not able to sustain that much pressure such such less volume.....ps it will create much more heat causing melting of piston inside cc
Himanshu Ninawe that's why I suggested a regulator. Good day to you
But how can we regulate a 85 bar co2 cannisters for this much small engine....and if we can....then it's gonna be the one of the best compressed air engines out there
well, the problem is the opposite actually. A gas will cool down as it expands. So you will end up with freezing valves and brittle plastic. There are numerous co2 engines that have been made going back decades. Google Stefan Gasparin and be amazed.
NissanIsAMentalDisorder well due to multiple piston cycles it will create much enough heat.....hope that should neutralize the freezing temps.
Was totally with you at 11:48 ... Great job, excellent video.
To cut washers at home use bits of pipe and punch holes through the rubber. For small washers you can get various sizes of pipe from old radio/tv collapsible antennas. Very neat project. I must build one myself :)
Awesome build! I've always wanted to replicate that old Air Hogs design, I had one when I was little. I'll have to support you on Patreon and use your design to try making an air powered radial engine for an rc plane. Keep up the good work, I love your content.
Yeah those airhogs planes were so cool! I searched for one to buy, but they're like antiques now haha! Thanks
This is absolutely awesome. Great work! Can’t wait to see it running longer. Love the sound!
''pretty good succes''
British inventing stuff in a shed is another one, classic joke on top gear, and true!
Why there are no piston rings or seals, I'll never guess.
spoken like a true engineer
I may have heard this on Top Gear, I'm not sure; "It works of course, but about as well as an electric car powered by a potato battery."
The late, great Doug McHard was something of an expert on compressed air engines. He used to shrink the bottles with a heat gun to make them fit better in the fuselage. This also thickened them up and allowed them to take a much higher pressure. With higher pressure you can reduce the lift height of the valve (perhaps make the pin on the piston height adjustable so you can play around with settings).
Great video man. I've been subscribed to your channel for a while now. That is to say I looked for this kind of thing back when I got into 3D printing. Keep that in mind when you read the next bit below. I have some knowledge in this area of engineering which might prove helpful in making that work a little better. I think part of the problem with it running so rough is that the cylinder or the valve orifice is too large. It needs some way to regulate the airflow down so that it can run longer on the volume of air pressure you have stored in the bottle. Something like a pin valve which I might add you can also 3D print.
All you need is a valve body and a bolt. Just grind the bold to a fine point by placing it in a drill and symmetrically grinding the end to a point with a Dremel or find grinding wheel of some sort. It doesn't have to be perfect so long as the taper is relatively concentric. The threads on the bolt will make for a great adjustment system. It just needs a small hole to seat into. This will cause it to have a strong burst at the beginning of the power stroke instead of the whole stroke giving you a much longer run time and smoother performance for the motor.
I built a similar motor out of machined aluminum as a final project in my machining course. It worked up to around 120 pounds of pressure without failing but got really hot in the process. I wound up cutting a new cylinder with fins much like a nitromethane motor for RC models for extra heat dissipation and it worked beautifully. The one you have there should work up to around 25 to 30 pounds of pressure just fine. It just needs some kind of flow restriction to help it run a little more smoothly. Kudos on a really decent design and thanks for sharing it.
Great content as always Tom and it was great to learn about a new type of engine. I work with a lot of 3d printed parts and have used compressed air in some projects, may try to make a multi cylinder version of this as it would be less lumpy. Please put on some safety on some safety squints as when it blows up it could do you some damage!
At the valve you already have an o-ring, you don't need a gasket. Also, cut a groove in the top of the cylinder and use an o-ring there. The better your piston and cylinder fit the longer the run time and the greater the power available. A true round piston with dynamic sealing like labyrinth grooves might help. It is a fine balancing act to find the proper length of poppet and spring to achieve maximum pressurization and expansion before exhaust. The exhaust ports on the front of the engine are actually anti-thrust so maybe an exhaust shroud would help. Screw threads inside the rod bearings are creating a lot of friction and wear. A study of miniature engines, that have been around a long time, will provide much information as to what makes an engine work efficiently.
Brilliant! This is going to revolutionize drone technology, eventually.
That's really awesome. Good work. I did some Legos stuff back in the day with air compressed motors and such.
Part of why it was so inefficient and rough sounding was because you were running the prop in the wrong rotation direction. You either need a different direction prop or to just face the prop twords the motor.
Should sound smoother and run with less drag!
Lubrication - expanding on Farm Bart's comment - the pins going through the con rod are actually screws and will chew up the copper bearings fairly quickly, particularly without lubrication. (These are "bearings" - just plain bearings rather than ball or roller bearings. They are more sensitive to lubrication than ball or roller bearings.)
Balance - flywheels are commonly fly-cut to improve the dynamic balance. You are losing a lot of power to vibration from the unbalanced engine. (Dynamic balance is a pretty tricky equation to solve, particularly for a single cylinder engine. A metal flywheel would help smooth out the engine but you can't 3-D print that.)
Piston rings - you are losing efficiency from blow-by of the piston. How much is hard to tell. Piston rings finesse clearance between the piston and cylinder. Small glow-plug engines commonly do not use them, but they have a lot of extra power to give away.
For greater efficiency at the cost of a little performance, you want the valve to close with the piston part way down. This way, the air gets to expand a bit before the exhaust ports open. If you don't lose as much of the energy to making a pulse of air on the exhaust.
I've been looking at the air hogs plane that is still in my closet, and wondering if I could use the motor to launch a glider. Your 3d printed version is so cool! And no, you were not too excited. My favorite part of the video is when your eyes light up in the pure joy of success!
Tip for cutting the washers from rubber sheet: Take a small length of copper, brass, alu, whatever tube of the correct diameter from a hobby store or hardware shop and sharpen the lip of one end to make a punch.
Also I would probably use the same to sleeve the cylinder.
THAT IS F*CKING AWESOME. no, you’re not “getting too excited over this”. Brilliant stuff!
Now you need to build a regulator for a controlled, extended run time. Cool project. You've got a sub!
This is AMAZING! I hope to see more of this project!
Make the connections to the bottle via the lid. I use the dip tubes from pump-action cleaning product bottles, simply forced through the lid via a slightly undersized hole. A 1.5l coke bottle is good for 60 psi in use and 100 psi safely (Without holes in the side.). I know this from making water bottle rockets.
The spring I think, gives a degree of regulation as the pressure goes down in the reservoir, at lower pressures it holds the valve open longer. A lot of the freeflight CO2 pintle valve engines do without the spring. Cool video.
Look forward to seeing the engine connected to a better air supply and possibly a plane!
What about sanding the cylinder with very smooth sandpaper, use an o-ring on the piston as a piston ring (one that isn't very tight against the cylinder to keep friction down) and lubricating the cylinder with a little grease, vaseline or oil? I suspect a lot of leakage around the piston and very reduced efficiency.
NorwayVFX for piston rings the best thing to use is RTV gasket maker if you make a groove around the piston and fill it full of rtv and shave off the excess and then use oil of some sort.
hater gotta hate
this is awesome! I've learned so much from this video
Tom: print an air regulator so that it runs longer at constant slow speed. Also print the
connecting rod pins onto the crank and piston so all you need is a nut onto the plastic pins instead of a metal bolt or screw. Might have unforeseeable uses on Mars but must lose heavy metal parts.
Also, make one-way snap together piston head and crank body, no screws, no glue.
FREAKING AWESOME! Now I really want a 3D printer
CR-10 is solid. Printed 500+ items on mine and developed a product that is now in production.
Excellent Tom! I think it would be nice if you could add a pressure regulating valve to the motor supply to have a more controlled autonomy and RPMS.
And something to think about ... Print a new piston with a small ring barely larger than the diameter of the cylinder so that it molds with silicone lubricant and seals the air leaks?
I admire your projects! Keep it up! Greetings from Argentina!
Amazing idea! Can't wait to see more of this.
Beautiful 2 stroke sound
Those things were all over my childhood. I’m going to buy a 3d printer now!
The brass pieces are called bushings, not spacers or washers.
Congratulations, you just became the 100th channel I subscribed to.
How does this guy not have 1 million subscribers yet...
Fun and educational video. Thanks for doing the series!
+Chuck Hawley thanks for watching!
Typical 2L bottle has a burst strength of around 150PSI (water rockets use these) and the best way to connect would be to make a new cap with a T on it, you don't need an in and out with air just the reservoir in line somewhere..
Tom, Hello! I really enjoy your vids, both the topics themselves and your presentation style. You seem quite personable and your explanations are well scripted. Keep up the good work.
PS A small amount of lubricant around the connecting rod's attachment to the crank wheel and around the skirts of the piston may help the engine both run smoother and provide a slightly better seal around the piston, extending the 'service time' of your air charge. Cheers!
Wow, that's quite a printing speed! :)
+coceg87 oops my mistake haha! ...err I mean it was matching the 60x timelapse ;)
Excellent design. I like it. Thanks for the video.
GENIAL. I think if you add exhaust tubes, they will do a slight vacuum effect, increasing the motor's performance
The look on your face said it all . . Well done keep up with great videos
You have the same reaction as me when something I build or fix actually works hahaha
Nice job Tom !!!
hey, I have done testing unto 400PSI on 1L and 2L pop bottles. the bottle cap is the weakest spot from my testing. I used a refrigeration compressor for my test with refrigeration gauges inline. use a fresh bottle and make the holes in the CAP and use epoxy for best results.
You say the cap is the weakest spot but I bet that only if the rest of the bottle hasn't been damaged right? I think the hole in the side of the bottle used in the video is the weakest spot. I second your idea of using a fresh bottle with holes in the cap.
Your average plastic water bottle will handle 90-100psi before bursting the cap off. Did it about a year ago with a bicycle pump that has the lever to hold the valve open and I used a bicycle inner tube and cut a round section out around it and made a hole in the cap. It literally smoothed the wrinkles out of the bottle. 😂 Makes one hell of a noise too. Spent over 20 minutes looking for the cap in my gravel driveway and it was over 40 some feet away in the yard
Michael Illingby *Hey guys, to improve the seal you can use a combination of SUPER GLUE + BAKING SODA seriously google it, amazing stuff*
With a pressure regulator and a light airframe, it would be a cool project to see fly!
what kind of monster would give this video 358 dislikes? This was awesome!
Oh, you are amazing! CONTINUE!!!!
hell ye man. thats nuts, congrats on another sucsessful prodject
You can make it run longer, just get the bottle lick proof, and put a valve in the hose, get some water inside the bottle and put dry ice, you will start building pressure, the coke bottle will take huge amount of pressure you will even see deforming, and open the valve and flight away. yeaaaa, Love you motor. fantastic.
That's incredible. Doing alot of printing myself I can admire your tiny tolerance printer. I'd be surprised if this doesn't get thingyverse verified
Great project tom!!
I say add a throttle to see if you can keep it running at a lower speed instead of exhausting your supply so fast, but this is exactly like the air hogs toy! Great job!!
+Eric Karczewski Yes I want to experiment with different inlet nozzle diameters to see if I can get it to spin a larger propeller for a longer period of time at a lower RPM. Thanks!
You could even just screw in an extra bolt to the side of the inlet, after the ball valve. Then tighten it to limit the flow rate. I honestly can't wait to see the next video, I might just try this myself with PLA and a drilled out cylinder!
I used to have a small car with an engine like this. When properly pumped, it would run blazing fast across the room. But the most enjoyable thing was to start the engine and then continue to pump the air while it runs. This sounded exactly like a real engine being throttled. You should maybe try doing same thing with this to get a continuous run.
I want to see a diet coke & mentos powered rc plane lol.
Zero Negativity wait.... MAKE THIS ENGINE COKE AND MENTOS POWERED AND LET IT GO
You're awesome tom!
I've had this airplane, it was a blast !! love your videos man
It sounds like a 2 stroke, very nice engine.
Hey nice job. Improvement idee: drill the cylinder for more presision, use some stell pipe or thing like that as part of the piston for more presision too, add more flywheel for more inertia an try to balance it for less vibrations, a piston a bit longer at the bottom can improve his guiding on the cylinder and WD40 can be magic.
Cool project. Maybe you want to use a drop of high viscosity oil to lube the joints and especially the piston to reduce friction and mainly seal the chamber a bit better.
That's pretty cool man.
So cool Tom!
Woah you’ve come far since I last checked in! Congrats dude
The challenge now is to 3D print a fuselage/air-tank, hand launch and fly it
Real model co2 engines have a much smaller displacement and turn bigger propellers. To increase the efficiency of this engine you could turn a bigger prop, and use a thick oil to reduce friction and fill in the tolerances. I assume the compression seal isn't great since the piston only fits one way. Also, if you were to make a v2, make the stroke longer in relation to the bore, this will keep the engine happyer with more load at lower rpm.
This is absolutely amazing