What is Cycloidal Drive? Designing, 3D Printing and Testing

  Рет қаралды 1,085,476

How To Mechatronics

How To Mechatronics

Күн бұрын

Register today at solidworks.com/3DXW22_HOWTOMECH for free Virtual Conference Pass at 3DEXPERIENCE World 2022.
3D model, parts list and more details ► howtomechatronics.com/how-it-...
If you enjoy and find the content that I make useful, please consider supporting me on Patreon: / howtomechatronics
Parts list (check website article for full list, affiliate links):
Amazon.com:
Bearing 6x13x5mm 686-2RS: amzn.to/3E4zZXf
Bearing 35x47x7 6807-2RS: amzn.to/3fATTgL
Steel rod 6x35mm: amzn.to/3FhqZ2I
AliExpress:
Bearing 6x13x5mm 686-2RS: alii.pub/66b1x0
Bearing 35x47x7 6807-2RS: alii.pub/66b1tw
Steel rod 6x35mm: alii.pub/66b1z5
Visit HowToMechatronics.com for more Tutorials, Tips, Projects and How It Works videos:
► howtomechatronics.com/
Like my page on Facebook:
► / howtomechatronics

Пікірлер: 270
@simeon7450
@simeon7450 2 жыл бұрын
Clean design. Clear and instructive explanation. Evaluated the results of the work. Original Content. Material list included. 3D Model included. Perfect video honestly.
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Glad you enjoyed it!
@BUILDwithMAULIK
@BUILDwithMAULIK 2 жыл бұрын
He’s a gem 💎
@snorttroll4379
@snorttroll4379 5 ай бұрын
are they lighter or just more compact? than gears i meaan. can they be used for an ebike??
@snorttroll4379
@snorttroll4379 5 ай бұрын
why the double layer of cycloid discs?
@str44thond71
@str44thond71 3 ай бұрын
to reduce vibration, the eccentric shaft is basically an off center shaft and the cycloidal disc is moving more side to side than rotation movement, so they put 2 disc in opposite side to cancel out the side to side meaning lower vibrations @@snorttroll4379
@EldonElledge
@EldonElledge 2 жыл бұрын
What a SPLENDID video showing such a brilliant design. I am a bit amazed at the accuracy you got from the 3D printer.
@louvoodoo
@louvoodoo 2 жыл бұрын
This is an absolutely beautiful design! Keep up the outstanding work!
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thank you very much!
@Angel-vc3bw
@Angel-vc3bw 2 жыл бұрын
James Bruton used Cycloidal Drives in his most recent version of the robot dog. And I somehow doubt that it did not inspire you a little. It's worth checking out
@JaridMitchell
@JaridMitchell 2 жыл бұрын
Thank you for reading my mind with this comment lol
@ArnaudMEURET
@ArnaudMEURET 2 жыл бұрын
That’s a very pleasant comment supported by solid arguments! I can feel it comes from someone who has watch many of the thousands of YT videos themed “let’s make a cycloïdal reducer”.🤦🏻‍♀️
@crowguy506
@crowguy506 2 жыл бұрын
Just another expression of wanting a Prusa XL.
@user-rl3xc9fw3r
@user-rl3xc9fw3r 2 жыл бұрын
This mechanism was my master's work during studying process, but yours is the best.
@TheNamelessOne12357
@TheNamelessOne12357 2 жыл бұрын
1. You can draw parametric curve from 0 to 180 degrees, then connect it's start and end, extrude half of the cycloid, and then just mirror it and get full shape. 2. It's better to use SolidWorks variables. This way you can change cycloid's shape much easier. 3. Efficiency was measured incorrectly. Does this motor really produce rated torque? Input torque should have been measured before measuring output torque. And it's also interesting how much torque will this reducer handle before something breaks. :)
@joaocamiloulhoa4878
@joaocamiloulhoa4878 2 жыл бұрын
Your channel is just amazing!! This deserved a scara pic and place with computer vision detecting objects!
@rdyer8764
@rdyer8764 2 жыл бұрын
Excellent as usual! I never expect anything less from your videos.
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thank you!
@queenidog1
@queenidog1 18 күн бұрын
I've made two of Mechatronics projects, the Mars Rover and the Scara Robot Arm. These projects are great because they are well thought out and designed, with lots of photos and construction details. Looking forward now to make one of these drives to learn about it and maybe use it in a different Scara robot arm. Good stuff Dejan! Thanks for this.
@sarabvirdi7116
@sarabvirdi7116 2 жыл бұрын
This video can really add value to the other old industrial applications . Great work👍
@e.s.6275
@e.s.6275 2 жыл бұрын
I'm an electrical engineer brought here by a chance, however I do have certain appreciation of the mechanical engineering. I am able to judge that this video presents an extensive engineering effort, showing itself both overall and in the details. I wish I could work with you on my energy conversion related projects (quite a lot of mechanical engineering is required there), or that my mech. engineers could represent at least a half of your ability and attitude to the subject.
@Rafitas_
@Rafitas_ 2 жыл бұрын
Great job! Thanks for sharing with us !
@jasonbenjamin1464
@jasonbenjamin1464 2 жыл бұрын
that was quite beautiful. elegant mechanics.
@BenM0
@BenM0 2 жыл бұрын
Awesome project! one of the best i've ever seen , Thanks for sharing, I really enjoyed it.
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Glad you enjoyed it, cheers!
@Neil-wp8nb
@Neil-wp8nb 2 жыл бұрын
Gorgeous design. And brilliant explanation.
@visualchallenge2413
@visualchallenge2413 2 жыл бұрын
In the first seconds of the video I thought the scene was a 3d rendering, so clean it is !!! until I saw your hand grabbing the device. Nice video and valuable content !
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thanks! 😀
@michaelknox5436
@michaelknox5436 2 жыл бұрын
Brilliant work and explanation!!!!
@Frog_cousin
@Frog_cousin Жыл бұрын
OMG Thank you so much for uploading this video Now I understand how to drive it
@temyraverdana6421
@temyraverdana6421 2 жыл бұрын
Wow! absolutely amazing project. Thanks for share your skills
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
My pleasure!
@johnpelitidis6297
@johnpelitidis6297 11 ай бұрын
Beautiful work :)
@mukuym
@mukuym 2 жыл бұрын
Amazing job, mate
@brandonb417
@brandonb417 Жыл бұрын
Hey all, just FYI, the equation as copied and pasted into SW had some issues. I copy and pasted it directly into SW2022 and it came up with something that looked more like a flower than a gear. After watching a video on Stepbystep-robotics channel I was able to figure it out. He had done some intermediate calcs on a couple of the terms and then replaced those terms in the equation and removed the associated parentheses that are no longer needed. This solved the problem. Also, in SW you can use the equation editor to lay out your terms and then put the equation into the sketch using the terms with, with " around each term. This makes your disk editable without having to re-copy/paste the equation in.
@michaelsabatiii6052
@michaelsabatiii6052 2 жыл бұрын
neat ! great job explaining.
@PhG1961
@PhG1961 2 жыл бұрын
Impressive piece of ingenuity ! Well done !
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thank you!
@KoenBrader
@KoenBrader 2 жыл бұрын
Wow this is a superb video. Subscribed & liked. Thank you!
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thanks!
@darkness1943
@darkness1943 2 жыл бұрын
Absolutely My Respect 👍🏼‼️
@tahirkamboh147
@tahirkamboh147 2 жыл бұрын
Great explanation
@kepagu
@kepagu 2 жыл бұрын
It thought it was a digital model, then you touched it and started interacting with it my mind melted for a second
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
hehe 😀
@zaxarzaxatcenko9246
@zaxarzaxatcenko9246 2 жыл бұрын
Ото мені чудо,хвильовий редуктор.
@heckyes
@heckyes 2 жыл бұрын
Wow. Incredible.
@NicleT
@NicleT 2 жыл бұрын
Beautifully done project! A transparent cover would be cool for showing what’s happening inside and dust protection.
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thanks!
@PaulGouldRobotics
@PaulGouldRobotics 2 жыл бұрын
Great explanation and great video.
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thank you! Your channel is quite inspiring too! Cheers
@aterxter3437
@aterxter3437 2 жыл бұрын
About the shaft : when screwing pla parts together, I avoid using purely undersized holes : there will be a lot of friction wich will generate heat when screwing, risking to damage the part. a common option is to use threaded inserts, but they are expensive and not always usable (tiny space for a screw, for example) personally, for 3mm screws (just for reference, my engineering project uses non less than 41 m3 screws all holes made with the following method) : a 2.3-2.4mm hole in the 3d model, that hole is re-drilled with a 2.5mm bit (inner diameter of M3, M5 is 4.2, for reference) with a cordless drill at slow speed to avoid melting the PLA, the hole gets a perpendicular exit (through part hole / I had in the model an other hole perpendicular at the end of the screw's hole) to make an exit for the debris, lastly the hole is slowly hand-threaded with a M3 tap and tap holder with a 2 turns down, half turn up, movement, to limit friction and let debris go down to the exit. If the hole is deeper than 15mm, I firstly do a 10mm pass, remove the tap and clear debris with a straightened paperclip, to much debris will make a lot of friction, heating up the pla and ruining the thread, so go slowly. Uses and personal recommendations : Fixing a pcb : a m3, 6mm long thread is enough. Fixing plastic parts together : a 10-15mm long thread is enough
@_VeljkoMiletic_
@_VeljkoMiletic_ 2 жыл бұрын
Good video! Bravo, brate! :)
@GFedya
@GFedya 2 жыл бұрын
It’s very cool!
@maheshpatel2005
@maheshpatel2005 2 жыл бұрын
nice work
@iiimtxt9685
@iiimtxt9685 2 жыл бұрын
Respect man. it's good job.
@Listener970
@Listener970 2 жыл бұрын
Beautiful!
@rawdiggs
@rawdiggs Жыл бұрын
I Love this video.
@Leroys_Stuff
@Leroys_Stuff 2 жыл бұрын
That is dang cool great video
@thecitiots
@thecitiots 2 жыл бұрын
Cool project!
@RajaaKahel
@RajaaKahel 2 жыл бұрын
Great job!
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thank you! Cheers!
@user-mg1hh3gw4b
@user-mg1hh3gw4b 7 ай бұрын
amazing! bro
@jstro-hobbytech
@jstro-hobbytech 2 жыл бұрын
Incredible
@smmsex
@smmsex 2 жыл бұрын
Превосходно проделанная работа 👍🏻
@solarroller09
@solarroller09 2 жыл бұрын
Beautiful my friend ❤️👍😍✨
@viniciusnoyoutube
@viniciusnoyoutube 2 жыл бұрын
Excellent video.
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thank you very much!
@cda32
@cda32 2 жыл бұрын
very cool!
@fouzaialaa7962
@fouzaialaa7962 2 жыл бұрын
these things love and i mean LOVE being submerged in lubricant oil !!! in huge tractors they are always full of lubricate oil and they basically never fail .... tractors put them on final drives becoz of there robustness ... only seals and oil leaks but the mechanism hardly fails
@TechThakar
@TechThakar 2 жыл бұрын
Awesome bro.
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thanks!
@AssHole5
@AssHole5 2 жыл бұрын
Wow the Design.❤️🇱🇰
@makingagent9652
@makingagent9652 Жыл бұрын
fantastic
@NabtescoMotionControl
@NabtescoMotionControl 5 ай бұрын
Great video on cycloidal drives ⚙
@HowToMechatronics
@HowToMechatronics 5 ай бұрын
Glad to hear it, thank you!
@aminassadi5104
@aminassadi5104 2 жыл бұрын
very good animation
@peterfrancis3865
@peterfrancis3865 2 жыл бұрын
This is nice
@matthewmeans871
@matthewmeans871 7 ай бұрын
I actually used your version with the 3mm shafts as it didn't cause failure and was preferably lighter.
@electronic7979
@electronic7979 2 жыл бұрын
Very good
@Dejawolfs
@Dejawolfs 2 жыл бұрын
love it
@TECHNEWSUNIVERSE
@TECHNEWSUNIVERSE 2 жыл бұрын
Amazing work sir. Please also work on DIY QUADRAPED robot.
@nou5440
@nou5440 2 жыл бұрын
10:40 SPACERS!
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Check out my favorite 3D printers, the K1 Max: amzn.to/3txQUC6 or if you are on a budget, the Ender-3 V3 SE: amzn.to/3FkCPus I hope you enjoyed this video and learned something new! If you'd like to support me making more content like this, please consider supporting me on Patreon: www.patreon.com/howtomechatronics
@tranminhtutu8020
@tranminhtutu8020 2 жыл бұрын
hey guy, i see project is sand table, it’s beautiful and interesting, you can make do it??
@gary00832
@gary00832 2 жыл бұрын
A sumitomo gearbox is the first thing I thought of when i seen this!! Try tearing one of those down to replace bearings!!
@gaizkitapowers
@gaizkitapowers 2 жыл бұрын
Congrats! Long way to come out with this, wasn't it? 3D printing and SW is like playing to be God!
@Gigaloader
@Gigaloader 2 жыл бұрын
I think the reason why cycodial drives are not used more widely in industry is the much higher friction in comparison to regular gearboxes.
@Gigaloader
@Gigaloader 5 ай бұрын
@@NabtescoMotionControl It is less than 1 % in comparison to regular gear systems. Regular gear boxes are everywhere....cycloidal gearboxes are very limited in industry mostly used for robotics. "Widely used" is subjective. From cars over wind turbines to conveyor belts - all still use planetary or regular reduction gears. Even Tesla's Drive unit is a regular reduction gear. ;)
@Gigaloader
@Gigaloader 5 ай бұрын
@@NabtescoMotionControl I think you are over reading my comment. I'm not saying they are not used. But in comparison to the amount of regular gear boxes they are literally a fraction in all industy. There has to be some reasons for that. Probably much more expensive to produce, more friction/heat, difficult to maintain etc.
@antoninperbosc1532
@antoninperbosc1532 2 жыл бұрын
Very interesting video on how to make our own cycloid motor at home, thanks for sharing with us ! On a 3D printer, the horizontal hole extension option is always problematic. I have tested it on many parts on my calibrated X1 sidewinder printer under ideamaker and this is not very accurate and repeatable, the outer parts are ok but the hole diameters are often oblong and always vary from clone to clone. First price 3D printer are good for POC but not suitable for a precision DIY part that must last. I hope that one day "How to mechatronics" will build a mini EDM machine with wire/electrode and/or a sls printer to allow home user to make complex and precise shapes in metal. I am pretty sur that most of us will be happy to sponsort him in order to product this kind of tools in opensource.
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Yeah, the hole expansion option doesn't solve all problems. Thanks for the input and the suggestion. I will take it into consideration. Cheers!
@zzz_ttt_0091
@zzz_ttt_0091 Жыл бұрын
you are a beast
@onradioactivewaves
@onradioactivewaves 2 жыл бұрын
AvE has a great teardown of one of these amazing devices.
@jamescrud
@jamescrud 2 жыл бұрын
AvE is a hack.
@onradioactivewaves
@onradioactivewaves 2 жыл бұрын
@@jamescrud this may be true, but he is also very knowledgeable when it comes to mechanical and electrical components of tools.
@jamescrud
@jamescrud 2 жыл бұрын
@@onradioactivewaves Well he''s very good at giving that impression.
@jalechavez6042
@jalechavez6042 2 жыл бұрын
Great....!!...Saludosss
@UnwrappingByMimiKoteng
@UnwrappingByMimiKoteng 2 жыл бұрын
Amazing
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thank you! Cheers!
@miliohm
@miliohm 2 жыл бұрын
Great!
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thanks!
@zerenzhong
@zerenzhong 27 күн бұрын
Great video with intuitive and inspiring design. Would you like to specify which bearing to choose where the crank shaft contacts with the cycloidal disks? I do wonder rollers or balls might serve the role better)
@woodworkingandautomation
@woodworkingandautomation 3 ай бұрын
Good explanation. Thank you! Who invented this cycloidal? crazy!!
@ahmadpourjavadi4223
@ahmadpourjavadi4223 2 жыл бұрын
Thanks for sharing. Thanks to the sponsor comlany made it easy for us to see your current project. I need to see again and put my questions later here. Can you name so e apication please. Thanks. PJ, Germany
@shogga690
@shogga690 2 жыл бұрын
Great video! I’m curious what efficiency did you calculate? In/Out Power efficiency?
@stm32user
@stm32user 2 жыл бұрын
After long time
@CMundi-kf9cg
@CMundi-kf9cg 2 жыл бұрын
Very good cycloidal drive to do cycloidal things.
@rvg557
@rvg557 2 жыл бұрын
Excellent work and video ! Congrats One question if I may : what are the advantages & drawbacks of a cycloidal drive vs a strain wave gear (harmonic drive) ?
@NabtescoMotionControl
@NabtescoMotionControl 5 ай бұрын
Cycloidal Drives have high load capacity advantages and high torque density, but come with higher friction and limited speed.
@Sergiuss555
@Sergiuss555 2 жыл бұрын
So happy to find this channel. I don't need porn anymore.
@shakerileiwat4341
@shakerileiwat4341 2 жыл бұрын
Great ♥
@olafberend8837
@olafberend8837 2 жыл бұрын
Greatly explained! And shown details are also very comprehensive. Is the output speed very uniform or did you recognize any unsteadyness. So you recommend these published formulas?
@piogrzes3082
@piogrzes3082 Жыл бұрын
Great
@aminsaba7693
@aminsaba7693 2 жыл бұрын
Thank you for your helpful video. I was wondering if you could help me out with 2 questions. How did you calculate the thickness of the disc and also how did you decide on the number of output holes on the disc ? Your video was a great inspiration, I hope to build my own version very soon. Thanks again!
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Glad it was helpful! I didn't put much time researching about those two parameters, so I chose them arbitrary.
@iqblayutub
@iqblayutub Жыл бұрын
I didn't know before that there was a gearbox like this after I opened a gearbox at my work, well little confused 😅
@boombox8675
@boombox8675 2 жыл бұрын
wow your video is very nice. i was experimenting with @James Bruton cyclodial drive model. would love to try with yours when i have enough filament. what is next harmonic drive?
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thank you! Go for it :) There's already a video for Harmonic drive from last year. If you've missed it, here it is: kzfaq.info/get/bejne/rtKegc1qq5mbfXU.html Cheers
@boombox8675
@boombox8675 2 жыл бұрын
ok will check out
@GHILLIESARCADEANDMORE
@GHILLIESARCADEANDMORE 2 жыл бұрын
Cool
@l0I0I0I0
@l0I0I0I0 Жыл бұрын
Can you recommend one or a substitute that will last decades?
@DEtchells
@DEtchells 2 жыл бұрын
Gorgeous design, and thanks very much for sharing the design files! In your test, the output torque was limited by the little stepper motor: Do you have any idea what the maximum torque is that the drive is capable of before breaking? It looks like it should be very robust!
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thank you! I didn't test much torque it's capable of handling. I wanted to test it with a NEMA 23 motor too but I didn't have the time. I might do it in future and post the results.
@juliannojungle
@juliannojungle 2 жыл бұрын
Great video, just loved the improvements on the design. Ball bearings are way easier to source than bushings. 5:10 "twenty-twenty"? Wouldn't it be "twenty-two" or "two-two" or something? Haha, anyway, that's a nice discount.
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thanks for the input. haha yeah, "twenty-twenty" :) I guess I worked way too much that week to publish the video.... Cheers!
@MogR91
@MogR91 2 жыл бұрын
Stop the parametric curve at 99.99% an jankily finish it with a little arc => Solidworks in a nutshelll XD This thing drives me nuts : gets crazy good, easy to use functions and drawing abilities to 99,99% and you spend days fixing the 0.01% because it requires you to rethink your design around it. Amazing gearing tho, really like how simple and compact these ones looks. But can't help to wonder about their durability and efficiency... not mentionning how expensive they are.
@Rs-uh6oy
@Rs-uh6oy 2 жыл бұрын
Please make a video on robotic arm 3d printer
@fredwupkensoppel8949
@fredwupkensoppel8949 2 жыл бұрын
I tried to wrap my head around this thing a couple of times; somehow I always missed the eccentric bearing, thinking it and the discs were one solid unit. It all makes sense now, lol
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Glad to hear the video was helpful! Cheers
@roquemorcillovalencia1847
@roquemorcillovalencia1847 Жыл бұрын
Por favor hacer el vídeo en español gracias es muy importante para mí gracias por la atención prestada
@tranminhtutu8020
@tranminhtutu8020 2 жыл бұрын
hey guy, i see project is sand table, it’s beautiful and interesting, you can make do it??
@vedmongia5018
@vedmongia5018 2 жыл бұрын
Can you please upload a tutorial on how to make automatic water level controller using 555 timer ic with theory and explanation
@proto_hexagon5649
@proto_hexagon5649 2 жыл бұрын
14:01 nice project. You try any brushless motor? What about vibration on the Cycloidal Drive? its not incresead?
@hansikabagga
@hansikabagga 2 жыл бұрын
everytime i dont know some concept and try to find it and still dont get it clearly,you upload it
@nooraldeenameeraljubaihi943
@nooraldeenameeraljubaihi943 2 жыл бұрын
Hey, thank you very much for the coolest content. Creativity. Looking at your site, I noticed two projects where you use the same tool, laser engraving machine by "scara robot" and laser engraving machine by "simplest CNC machine", I guess the question, what is the use of laser in scara even though there is a simpler CNC machine that is easier to use and less expensive, but most of those interested in this field use the same idea of ​​the simplest CNC machine as it develops. scara . is not used
@HowToMechatronics
@HowToMechatronics 2 жыл бұрын
Thanks! Well that's for those who want to learn more about robots. I showed a way how to control the scara robot to work as a laser engraver.
@ArielGTami
@ArielGTami Жыл бұрын
Beautiful. By the way, what if the outer part is driven by a second motor. How does output speed changes?
@ricnyc2759
@ricnyc2759 2 жыл бұрын
And the friction!
@tanjiro3285
@tanjiro3285 2 жыл бұрын
💗💗💗💗💗Biiiig Fan
CNC Machined vs 3D Printed Cycloidal Drive
19:58
How To Mechatronics
Рет қаралды 698 М.
Дарю Самокат Скейтеру !
00:42
Vlad Samokatchik
Рет қаралды 6 МЛН
버블티로 체감되는 요즘 물가
00:16
진영민yeongmin
Рет қаралды 124 МЛН
Flywheel Battery
14:49
Tom Stanton
Рет қаралды 8 МЛН
I Don't Get Why People Still Use These Joints
17:26
Lincoln St. Woodworks
Рет қаралды 102 М.
The Future of Auto Manufacturing: AI Driven Design
20:17
New Mind
Рет қаралды 962 М.
How are Microchips Made? 🖥️🛠️ CPU Manufacturing Process Steps
27:48
Branch Education
Рет қаралды 2,5 МЛН
120Nm 3D Printed Cycloidal Drive
19:44
James Bruton
Рет қаралды 227 М.
Harmonic Drive® strain wave gear - zero backlash
2:09
Harmonic Drive LLC
Рет қаралды 169 М.
I made a precision gearbox - with NO GEARS.
30:09
Not An Engineer
Рет қаралды 1,4 МЛН
Gearless Magnet Bike
17:57
Tom Stanton
Рет қаралды 6 МЛН
The Material Science of Metal 3D Printing
15:00
Real Engineering
Рет қаралды 2,6 МЛН