Rocket Powered Golf Club at 100,000 FPS

  This is a rocket-powered Golf Club. Professional golfers have an average swing speed of 110 miles per hour. But using two F sized motors she swings at a hundred and fifty miles per hour, every time. Usually for builds on my channel I just show you guys the final thing and don't really talk about the process of how we got there. But rest assured, today, we will get to see huge drives, WOAH! golf balls shattering glass in super slow-mo, pulverized watermelons, and even a handheld version. But this build, I think, is a great chance to pull back the curtain and demonstrate how the engineering design process actually works. I want to highlight six- "Learning opportunities" that led us to this final design and to do that, We need to go back in time four months to when I first had the idea. 

And as always we started with a simple Prototype to see if the concept even had a remote chance of working. Before we fire it up, you'll notice we have counterweights on the opposite side here. That's so that the center of mass of the spinning part is on top of the axis of rotation. In other words, It balances perfectly at the point at which it spins around. If you don't do that for something that spins it creates a bunch of extra force for your system to deal with. It starts as a small vibration, But then it gets worse and worse as you pick up speed. Since we needed to hit this tiny ball with the head of this club at really high speeds, if we're not perfectly balanced, the club and the whole platform itself will just be shaking all over the place and we'd never hit it. OK, back to the test Those stands are shaking more than they should so we knew we would need to balance the spinning part better for the real test But at least we knew it could go kind of fast and nothing blows up And so then it was time for CAD Which is always the next step and then together with my friends, Ken and Kayla. We started cutting metal and making stuff Things came together well so we epoxied a 3d printed motor mount to the top of the driver and prepped our first real test by taking one of Those easy ups and draping some nets on the side for safety just in case something went catastrophically wrong 

This was our second learning experience, we didn't have enough contact area for epoxying the head to the driver So it wasn't a strong enough bond this was tricky because it meant we had to 3d scan the club head which allowed us to CAD up and then 3d print a more contoured mount with more contact area for the epoxy We also took this chance to double the rocket holsters because what could possibly go wrong? So we went to test our new dual rocket set up with two e motors and everything went perfectly Except for the part where the head snapped off the driver And when we reviewed the slow-mo footage what we realized was the shaft of the driver is so flexible that it would start to bend And then create really weird thrust vectors for the Rockets which then just bent the shaft even more This is not what you want to see. Eventually it succeeded the stress limit of the shaft and the head just came off So our third learning opportunity was to stiffen up the club shaft So we got some aluminum c-channel and just dumped a butt ton of epoxy in there and this worked remarkably Well, you can see the difference here. And so with that we headed out to a very remote shooting location in beautiful, Northern, California So we finally arrived and started to set up but first I have something I wanted to get off my chest so one of the things I like most about me is that I will I Like to reach out to lesser known channels and sort of give them a hand out at some exposure on my channel Which is why today I'm here with Destin And Smarter Every Day and if by some miracle you don't know Destin is on the Mount Rushmore Of science youtubers we've been friends for almost exactly six years and I know this because I took a screenshot of the huge moment for me when he subscribed to my channel when I only had 10,000 subs he's made videos about the physics of cats landing on their feet, 

tattoos in super slow-mo or the first video I saw of him about how chickens have an internal open feedback loop which allows them to head track if you've never seen his stuff I'm actually jealous because you have so many hours of high-quality viewing in your near future So I like golf. I like Rockets Should we do this? Yeah, let's just... That that was the intro right? That was it. Whatever so we all continued to set up and something that was important to me was for this to look as natural as possible at a driving range so we added some turf to cover the base plate and then Dissected a golf bag to cover the sturdy steel column and then if you add some clubs it looks pretty awesome It's incredibly rigid and yet it can still swing freely Our fourth learning experience came from reviewing our final test footage if you listen, the club goes faster and faster with each rotation Naturally we want the club to contact the ball when it's going the fastest which in our case is ten rotations in one second that Means we somehow need to sneak the ball into the path of the driver in less than a tenth of a second or a quarter Of an eyeblink to accomplish this we have a pneumatic cylinder here that hinges up the tee It knows when to fire because on the back of the shaft There's a light sensor and this disc has a slit which allows the light to pass through once per rotation So we send that info to an Arduino over here that counts for us and then after 15 rotations it tells the cylinder the precise moment to fire using a solenoid and then we superglue the ball to the tee because it provides the Goldilocks amount of force to first secure and then release the ball plus the superglue looks super dope in slow-mo So now with everything in place we started with two e motors which is a Reminder is the same setup that ripped the club head off three two, one roll Where'd it go? What happened? YEAH, BABY!! No way that's a cool shot right there. it is Dude this is uh, this is respectable This is legit after reviewing more of the high-speed footage. We noticed something interesting The sound effect there is like "doy yoy yoy" This was an interesting technical observation from Destin and that tee flexibility was causing us to hit some bad shots like this The obvious fix is just to make the tee more rigid so that it doesn't over rotate when it pops up 

But there's a problem with this There's a saying that force follows stiffness and for us a really stiff tee would transfer a bunch of force and destroy our nice 3d printed pop-up mechanism Now imagine this crumpled up piece of paper is the tee which is obviously way less stiff Our flexible rubber tee was great because it acted like this piece of paper no matter how hard you hit it The force doesn't get translated down and damage our hardware So Ken had the brilliant idea of just tying a string to the tee and staking it into the ground This stopped the over-rotation but everything was still just as flexible when the string pulls tight does it make the ball fly off because it's it doesn't doink enough? Uh, the only way to test is the doink test Ah, beautiful there was some doinkage I just thought this was a really simple clever idea that solved both problems at once and as you can see it worked perfectly Now we are ready to try a dual F motor So these deliver about twice as much force to the club as the e motors that made the head snap off and this Provided our final and certainly most poignant learning opportunity. 3 2 1 go Where's the club It's, it's, is the tree on fire?  Wow, like I'm laughing, but that could have been bad There we go, this thing was like sub-orbital dude. So we have three u-bolts and we only used two Yeah So I think we'll just max out those and just crank them way down now that we know this is a failure point Now that we know this is a failure point There's several failure points and I hear you say, oh we have a solution for that This is the engineering design process!! Rather fun. Like I mentioned the club that failed was cut too short and was only attached using two u-bolts Which we thought would have been enough to support the 800 pound load from centrifugal force We did notice the rubber handle was worn due to so many test fires which probably initiated the stress concentration leading to the failure So our fix was to cut the next Club longer so we could use three u-bolts and really crank them down on a fresh rubber handle and so with all six of our learnings now in place we tried the Insane double F motors one more time WOAH!! YEAH, BABY!! GO!! THAT's how you play golf! That's our best one yet! Dude. Like the rush you get from like an engineering achievement actually working in like. Seriously dude. Oh look at the flame. OH yeah! So we never found these long balls to measure the exact distance But I can drive a ball 280 yards and these were well beyond that. I mean just look at this trajectory straight to outer space Now that we've got all the shots we needed it was time to have some real fun We started with a handheld version that was powered by a single C motor because anything more than that would just be way too unsafe For me to hold Ni-ice! [unintelligible] over 300 yards man! It really did Like make it so much easier to swing I'm not even kidding. Yeah. Yeah yeah, like it really meant different 3 2 and then some glass just because YEAHH! 

And then keeping with the tradition of my channel some watermelon Thanks for cutting open a watermelon with a rocket-powered golf club Mark. You're welcome Yeah, that's all of this the past three months of work in engineering was just for this Boils down to this moment just to enjoy this watermelon. Yeah, Mark's like trying to make stuff look good We're not wasting food though we waste no part of the engineering effort like the great Indians with the Buffalo so Destin made a video on his channel about why some balls bounce high and others Don't and my first thought was well that's easy just has to do with how compressible or rubbery it is Yet this billiard ball is pretty much completely Solid and this bouncy ball is pretty rubbery and yet they bounce to pretty much the same height So it's something else. As you can imagine this is a pretty important piece of information for golf ball makers so there's lots of amazing slow-mo footage of golf balls being Squished in ways that hurt your brain plus way more footage from today's shoot So I will leave a link in the video description And while you're there make sure to check out some of his other videos and subscribe to his channel because he's just a classy individual And a true professional in every sense of the word. Are you rolling? Yeah Hi, it's me mark If you want to make your own rocket powered golf club You can find all the CAD files and the parts list even the code for the Arduino on a website I created called Mark Rober build instructions dot com and on that site 

You'll actually see build Instructions for tons of videos from my channel including my workbench and it's all for free and made possible by my friends at Wix.com And my personal design aesthetic is simple and clean. So I used a template to get me close to what I wanted But then I was able to customize it as much as I wanted from there And this is great for me because I get a lot of questions about the builds on this channel and now I'm able to just point People to one spot and because Wix is on the ball, it automatically looks amazing on mobile Plus, it's SEO optimized If you're looking for people to find your site through Google and my website is just a simple way to communicate information but you can make one for your personal brand or Portfolio or maybe a new website for your business to sell stuff online Or even book appointments right there and it's free to sign up to start designing and publishing plus It's really fun and a little bit addictive so to flex your creative muscles and to support Wix because they support me. Go to  wix.com/go/markrober or just use the link in the video description. Thanks for watching [awesome montage]