Building a 3D Printed Wankel Powered Paddleboat
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- Опубликовано: 29 май 2021
- Using Integza's compressed air powered wankel engine, I built an old-fashioned paddleboat. But because I over-do everything, I also designed a 3D printed air regulator to significantly increase engine runtime, and I learned how to run CFD (Computational Fluid Dynamics) analyses in order to over-optimize my hull and paddle design. The CFD was definitely overkill, but it was fun to learn and really cool to see how minor design changes can significantly impact fluid dynamics.
Check out Integza's channel and his Wankel related videos here!
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• Compressed Air Triangu...
And as always, the project is fully open-sourced (with minimal documentation of course!)
github.com/DDeGonge/AirWankel...
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#3dprintedlife #wankel #rotary 
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Thanks for watching! And an extra special thanks to the man, the legend, Integza. If you somehow have never heard of him, check out his channel! ruclips.net/user/Integza
Nooo waay integza makes a car, and you make a boat!
you can use the co2 canister. they are really safe actually. Bikers use them all the time, so long as the device that punctures them is store bought you will be fine. Keep in mind that these things are way over engineered to not explode. I have used them my whole life and misused them as well and I have never seen one get so much as a dent. (1000psi helps with that lol)
Hey, you used a rubber band as a belt. You held it on the engine side with a deep groove. You should try to make it more ball-shaped. Flat rubber bands actually walk up these walls, so if you make it more like a sphere, it’ll always end up on the center of the sphere.
You smart.
I follow you.
Love your regulator design.
Looking forward to the liquid piston design.
Have you looked at how good the old spring ball and cam air control was for controlling power over a range of pressures?
Have you considered an air powered triple expansion steam engine print?
If a rubber band keeps climbing out of the groove try making it bulb outwards, the rubber band will climb the top of the ball and stay centered.
ruclips.net/video/TNuzi-jMXoY/видео.html
just wanted to say this too. Or he could use a round rubberband. This would stay in the groove. This would also help the torque, cause it looked like it was rubbing against the paddlehousing because of this effect
That's what I was gonna say
Yes, it looks kind of counter-intuitive but it’s really the way to go.
I come looking for this exact comment!
Delicious counterweight? Might be your last collab with Inetzga
Yup
Inetzgas Wankel engine car was absolutely horrible, he made 0 adjustments to his first design. I lost so much respect for him.
It honestly made me question his other projects
@@thereinthetrees_5626 _" I lost so much respect for him."_ Pathetic.
@@thereinthetrees_5626 have you made your own wankle engine then?
@@ferrumignis What’s pathetic about it? His last video was pathetic
1. Float
2. Don't sink
3. Move forward
That made me lol. Great video!
Maybe reduce the hull to merely protecting the engine and housing the paddle, and then use 2 pressured water bottles as pontoon. More air, less mass since you dont have the need for a large hull and less frinction since the bottles are aerodynamic already and lighter then 3dp buoyancy
Ohhhh that's a great idea!!! V2 I suppose :)
or add hydroplanes
Was thinking exactly the same thing
@@prawnmikus fantastic name you have
@@THESLlCK Why thank you kind Mike. Why the Mike can't everyone have such a Mike name? They're missing out.
Can't wait for the liquid piston rotary!
I freaked out when he said that
Rubber bands need a convex curve to stay in the center instead of a concave curve, that is why the rubber band was giving you issues. This video of steve mould shows you why this happens: ruclips.net/video/TNuzi-jMXoY/видео.html
I was literally just on integza's latest video talking about needing a regulator and then I got recommended this video. Also, you should use crowned pulleys for your belts to keep them from slipping off.
Haha perfect 😄 and thanks for the tip!
@@3DprintedLife which was in another video I watched yesterday. coincidence???!!! ruclips.net/video/TNuzi-jMXoY/видео.html
I was about to recommend the crowned pulley , but came to check to make sure I wasn’t just repeating what someone else said.
@@TuttleScott we are the same person
@@TuttleScott there's a Matthias Wandel video from 11 years ago that covers crowned pulleys as well, check it out if it hasn't been recommended to you already.
I know this is going to sound counterintuitive, but instead of a deep groove, use a convex surface on the pulley. It's the same concept bandsaws use. The belt wants to climb naturally, so in a groove pulley it will try to climb out. On a convex pulley it climbs to the center.
For the rubberband issue you can use an crown pulley, I think that’s the name, but it is a pulley shaped the opposite way as you have now. Due to the stretchyness of the rubber band it Will seek the center of the pulley and will not fall off.
Actually I seen Integza's first but. I am glad to find another channel.
Very cool, great project. Would love to see further iterations. I have a very soft spot for 3d printed engines, keep pushing!
It’s pretty cool that integza and you made a use for that Wankel engine and both in a different way,
I really enjoyed both videos 😁
Glad you liked it! There was some coordination to make that happen :)
Check out Steve moulds video about convex pulleys, your rubber band slips off because it needs to be convex, not concave!
...As recently demonstrated by Steve Mould: ruclips.net/video/TNuzi-jMXoY/видео.html
I love rotaries and work on lots of them. This is really cool to see. Keep up the good work!
Thanks, will do!
Love the collaboration, awesome build!
Damn, that's some super clean video. Congratz ! I love it
Subscribed. Cool video.. you got through all that trouble of using CFD for a small boat! props to you!
Much appreciated! And yeah, certainly overkill but it was fun!
About the elastic band, you should make the groove outward! This smart British big youtuber (sorry forgot his name haha) just recently made a video about this. It's really interesting!
Steve Mould i suppose?
@@diamonddogie yes thank you haha
Exactly my tought !
It was Steve Mould
Superb with 3d printing quality was superb
pulley wheels for rubber bands have no "fences" but simply a roof shaped ridge in the center of the pulley. The rubber tends to climb up any rise and so will stay in the center of the pulley. My daughter figured this out in a school project - fastest rubber band driven vehicle.
woww awesome video they just keep getting better and better!!
Sorry, who dis?
What a well presented video. Subscribed!
I'm a subscriber of your channel and Integza's and I thought what a coincidence to see two channels uploading a video about the same engine at the same time.. Now I know why..
The rubber band in the deep grooves wants to climb out of it naturally. use a crowned pulley and it will actually self center due to the stretch of the band. Steve Mould did a very good video on this. Its counter-intuitive, but it works perfectly.
edit: guess i should have read the comments. That video hit everyone's feed a couple days back and so we all commented about it.
Yeah a few people mentioned this! If only his video came out a week sooner!
@@3DprintedLife I'll offer different advice then lol
The boat is too flat on the bottom and therefore doesn't have a self stabilizing hull. giving it more of a V hull shape would keep it from wanting to fall over so much
Oooh that's a new one, I figured there was a reason most boats weren't flat but I figured it was more for efficiency, not stability. Thanks for the tip :D
massively underrated channel, keep it up :)
the pulley on your flywheel is concave, which is making your rubber band spend a lot of energy trying to jump off the pulley.If you make the pulley on your flywheel convex, then the band will stay on the flywheel without using much energy, which will translate to longer run times. also if you use a 2L bottle, then make the boat longer and wider.
Read up on crowned pulleys to stop that band falling off! Brilliant video mate
I'm working on a two rotor version of the integza engine to counteract the natural vibrations of the single rotor. I plan on feeding the exhaust of the primary rotor to the secondary since there shouldn't be any contamination from combustion.
Ditto on the Bart Bols thread comments, you need a crown pulley. Krasum H linked the full video explaining why. Love the build, and your presentation was great. Thanks and keep it up!
You should premix your resin with graphite. And because you're not combusting anything inside your rotor, you could probably add some silicone grease to it as well.
I'd also suggest putting a superhydrophobic coating on your entire boat, such as using fumed silica or lycopodium powder.
YAY Liquid Piston!! I'm no investor, but I love that engine. I've love rotary motors since my first car, a 71 Mazda R100 with a 10A Wankle in it. The Liquid Piston motor is the future of rotary motors.
Working with Integza and calling tomatoes as "delicious counterweight" is a heresy, I guess :D
You want to use a convex curve on your pulley to keep the rubber band centered. It’s counter intuitive to think a band would stay centered on a bulge rather than centered in a groove. But that’s exactly what happens. It’s called a crowned pulley and it’s necessary with band driven mechanisms, like belt sanders and whatnot. It’s a mechanic of the band itself, rather than the pulley. If you use a band that’s as thin as it is wide then you would make the pulley concave like you did. Which is probably why it would on run when you ran the belt on its side, the thin part of the band
Crowned pulley belt drive is preferred for flat rubber belt. The belt would self-centre itself on the pulley. The reason why the belt kept climbing out from your pulley design is because of how flat rubber always 'climb' on higher level side instead of falling into the ditch. There are quite a lot of videos about crowned pulleys on YT.
If you are using a stretchy flat belt, instead of grooves you want essentially a positive curve (bulge if you will) on the outside of your pulley because of weird physics, that way it will self straighten and align.
flat belts require oval pulleys to self-center, quite efficient. Or use an O-Ring as a drive belt. Also, you could have a 3D printed drive train of gears going from the Wankel to the paddle wheel.
Excellent content! Subbed
Hey! To keep a rubber band stable on a pulley, you need to do the opposite: Make a crown, not a groove. It’s counter intuitive, but the band wants to climb up to the highest point, that’s why it kept climbing out of the groove. If the highest point is in the middle, it will be stable.
I posted on Integza's video on the engine and I think it's relevant here also:
I think the engine would be better if instead of using a bypass, it was dual in/out. They could always be connected via a splitter to the same source and allowed to free vent on output.
Then each half of the engine would be used for the motion and it would likely increase the torque you could get out of it.
Im excited to see the liquid piston
Rubber band trying to escape from the groove - bandsaws use a crowned wheel to hold the blade. Counter-intuitive, but the geometry of how a band slips off a wheel makes it work.
9:40 Here’s a little tip to stop the rubber band from falling off, the pulleys need to be convex instead of concave if you’re running a flat belt.
I have a solution for the rubber band thing, make the pulleys kinda spherical! It's counterintuitive but Steve mould has a great video explaining why it will work
Ohh yeah I remember seeing that in my suggested feed a few days ago, guess I should watch it!
@@3DprintedLife smart conclusion
Is it bad that I somehow miss your old dorm room videos?! These new ones are just too polished! 🤣🤪
Ikr, I really need to stop putting in so much effort :D
An out rigger may help. You know those thing you sometimes see attach to a canoe out to the side, small pontoons. Well not only would you be able to get ballast from that (keeping the boat balanced, side to side) you could also fill them with more air therefore more "fuel".
Instead of making the pulleys concave with deeper grooves, make them convex. In other words, rounded 'out' instead of 'in'. The flat belt or band, in this case, will actually climb up the shape and self-center on the pulleys. Steve Mould just published a video explaining why.
When using a rubber band, counterintuitively, use a bump instead of a groove for the pulley and it will centre itself (belt sanders use this principle)
Invert the pulley groove. With rubber bands you want a fatter center and a thinner edge wall and this causes an inverse affect bringing the rubber band to the center. You have a ton of friction in the pulley with the deep channel. I know it sounds counter intuitive, but it’s true. ONLY APPLIES TO ELASTIC BANDS. Old tractor PTO’s were designed like this because they discovered the same thing happening to them.
Use a bump instead of the groove on the pulley. It is a self centering mechanism and keeps the rubber band nicely in the middle.
Extremely fun and interesting video. Small tip is to use convex pulleys (largest diameter in the center) if you use a rubber band as a belt. Seems counter intuitive but that is actually the case. It won't slip off.
Oh well, I guess this was already well known in the comments.
Hahah yeah, just a few times 😁 if only that video came out a week sooner
I learned from Steve mould that curving pulleys outward actually prevents flat belts from slipping off, you should try that in the next iteration if there ever is one
A simple solution to your stretchy belts, instead of going the bell pulley route, use large o-rings. I've used them on many university projects in the past and have worked well. I normally use Nitrile o-rings. If you're a savvy shopper you can buy them in bulk and have plenty spares of various size on hand for future projects.
The rubber band issue is actually counterintuitive. Steve Mould did a perfect video explaining it titled, "The Band Should Slip Off But It Does The Opposite!" The way you designed the bands to sit on concaved pulleys will actually encourage the bands to climb up the sides and fall off, since you are using a wide band rubber band.
You could look into the X bow, the axe bow, catamaran, deep V....well let's just say: "there are a bunch of bow, hull and stern designs to look into." Not to mention all the propulsion and rudder/steering designs you could use aside from the paddle wheel and standard rudder.
Your pulley system can be simplified if you use a rounded ball on the output side of the belt it should self center to the apex of the curve. Only really works because of the stretch of the rubber being tightened on one side at a time.
For belt tracking with a flat belt (like your rubber band), what you really want is a convex pulley. There are lots of good explanations for why on youtube; but that could be a simple upgrade to the belt drive.
10:52 nice Sirene in the Background 😉
And nice Vid! 👍👍👍
I dont know if 3dprintedlife will see this, but there is a way to keep belts like your rubber band drive belt on the gear without it always slipping off and not using really steep slopes to keep them there. I dont remember who i learned it from but a belt will stay on if you invert the slope so that it looks more like a donut.
Something about the sides of the band being less stretched than the middle keeping it on (similar to how belt sanders work). If you use a belt like the one in the video on a different project, give it a go. (Do note that it only works with wide belts and not thing ones)
9:40 yeah your rubber band is a *band*. those try to climb *up* rounded/sloped grooves. either make it perfectly rectangular in cross section, or make it convex instead of concave, as dumb as that may sound it helps it selfcenter (by stretching the side that's on the larger diameter a bit, making that pull the other side towards it)
The plastic bottle you are using already have a very efficient boat shape. You could use it as the boat's body, instead of putting it on top, reducing stability. If your engine setup is airtight, fixing under the bottle (under water) would give you a good stability. It requires to add a cone in front of it to reduce drag. The add two lateral floats to the bottle to prevent any spin, put the paddle wheel on the back and you have a light speedboat.
Maybe something like a catamaran with a dual bottle/hull configuration and all the mechanical parts in the middle could even be able of RC direction; whit more air capacity, and less weight can give you more run time, and if you uses a propeler instead of the paddles you get no rubberband isues.
At 9:40 you talk about climbing out of grooves, Steve mould made a video about rubber bands doing that, if recommed checking it out, but I summary, with rubber bands groves do the opposite of what you expect and making them bowed instead actually helps
For rubber bands you need convex pulleys vs concave grooved pulleys to prevent them slipping off. Steve Mould has a good video on it.
The elastic band will always climb out of the grooves of the pulley wheel because it has elastic properties. To avoid this you have to make the pulley wheel exterior convex. This also may require a larger thickness of the wheel.
One of the reasons your belt might be climbing is because its groove is concave, which gives it a wall to climb. If you want Steve Mould has a really cool video on crowned pulleys that explains why this happens.
You can get much better efficiency out of those pulleys with a flat belt such as a rubber band by making the grooves bulge out instead of cupping in.
small tip, pullys for wide drivebelts like ur rubberband need a slightly convex form, they adjust themself then. Beltsander use the same principle.
Just let it tow the bottle. Great vid!!!!!!!
you can direct the exhaust backward to propel the boat more, or use it to move the pedal master
If you plan to keep on using rubber band belt drives try a convex pully design, i don't fully understand the mechanics my self but a video explains why it keeps the band centered I'll edit this later if I can find it
You can put a bottle on a long beam and use it as an outrigger to prevent the boat from flipping
You should've used convex pulleys instead of deeper concave one. Rubber band stays in the middle of a convex shape when spun but climbs up the walls when concave. Steve Mould just made a video on it.
The reason your rubber band kept climbing off the pulley is your pulley was concave instead of convex. If you print a pulley that looks like a squashed sphere it won't try to climb off of it. Instead it will self-center. It's not very intuitive. In fact it's very counterintuitive.
im just busy 3d printing an a bit larger catamaran, and came to the conclusion its way easyer to print holders for empty 1.5L bottles to carry the boat then spending a lot of time printing a hull and then trying to waterproof it.
If you want your belt drive to stay in place, instead of using a convex pulley, use a concave one. It will keep in place because of speed differential of the band. Steve Mould made a great video explaining how this works :)
That would also help with load handling of your pulley..
You mean, instead of concave he should have it convex :)
This was great, thank you for explaining why it would be beteer to use a regulator than using a smaller outlet. Nice fly wheel and pulley. What would it take to design a 3D printable compression tank.
Protip, don’t make rounded grooves when using a rubber band, it’s actually better to make a convex bulb, because of the climbing thing. I’m sure you knew this cuz you’re a smart bean but I just learned this the other day and I was proud
If you want to run more efficiently, make the boat more buoyant and reposition the exhaust to be horizontal. This way, the exhaust will propel the boat forward giving it an extra boost, as well as removing the downward force it is exerting, in turn giving less drag.
Tip for the pulleys: your pulley profile should be inverted. The rubber band won't climb the edges of the pulley if they're tapered downwards. Seems counter-intuitive but it works.
9:40 I've learned recently that if you you're using a band you want to use the inverse of a groove if you want it to stay on, otherwise it will crawl out of a groove.
With the wide belt convex instead of concave pulleys might help, they're self centering
That's gold!
for flat rubber bands you need domes not groves to keep it centered
If you want you can try using a spherical bump instead of grooves because a rubber band would want to move to the center of said bump due to weird physics I don't feel like explaining.
its surprising that a channel with such high quality, and interesting videos has so few subs... yt algorithm sucks. prove me wrong.
9:38 You could try an outwards curved belt pulley. This is maybe counter intuitive, but the belt should maintain in the middle that way. You can check out some old machinery, they work even without the sides.
You need a nice Long keel underneath and maybe even some Pontoons on either side... The Paddle propeller you got going on there is more like a paddlewheel boat with very small paddles. You know that though. Obviously bigger paddles on the wheel would be the way to go coupled with the keel and pontoons as the setup you have is top heavy.
Try using an O-ring as a drive belt. Less stretchy, available in a lot of sizes.
That’s sick
Hey just so you know, concave belt pulleys actually force the belt to climb out. It's counterintuitive but convex pullyes will center the belt naturally. Just look at how belt Sanders control belt tracking.
Super cool
Hi! I enjoyed your video and wanted to make a few comments. I hope you don't mind! First off, if you're using rubber bands for belts, you should look at crowned pulleys. It's counter-intuitive, but you're losing a lot of energy to friction with those deep grooved pulleys, and the concave bottom of the groove is working against you, as it's actually trying to push the rubber band out of the groove. Second, consider ditching the fancy 3D printed hull and using the pressure vessel as your hull. Better yet, use two of them and make a catamaran. You'll get more volume, less weight, and a more stable flotation. The last thing is I want to compliment you on your regulator design. I made something using the same principle a while back but it was a lot bulkier and heavier than yours. I'm inspired to revisit it now and try and make it better. Thanks for the inspiration! Cheers!
Next time you want to use rubber bands for a pulley, I recommend looking into crowned pulleys. They will keep your band running true just off the width of the band itself
Thanks for the tip!
Try a w shape for the pulley. It might sound stupid, but the belt should naturally climb onto the central point on the w shaped pulley.
Put two bottle on each side with pressurized air and the paddle assembly in middle, this way you can have more stability as well as more compressed air. Something like catamaran boat I guess.
You need to make a crowned pulley to keep the rubber band on. A concave groove will actually cause the band to walk off.
instead of a groove, you could use a convex. i know it seems counterintuitive but with wider belts it keeps it on.
i discovered your RUclips channel via integza's video
Awesome, welcome!
To keep the rubber band centered and on the hub, put a small radius opposite to what you had shown. Search RUclips for “The Band Should Slip Off But It Does The Opposite!” by Steve Mould
I'd use the bottle as the main buoyancy element of the vessel, then just run a hose to the back where you have the power pack and some stabilizing pontoons