Even nerds can dunk with these
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00:00 dunk personally. So I decided to engineer some ups. These are dunk boots. Imagine a dunk so high
00:08 you have to be on a rope or you'll break your legs. You know what? You don't have to imagine
00:14 it because that's what we're doing. Well, after we work out the kinks.
00:26 These are really similar to Inspector Gadget's boots. Do you remember Go Go Gadget boots?
00:30 And that was basically my mission statement for this project. Extendable stilts on command that
00:36 could make me ascend into the heavens and that ideally I could take a step with. Which I
00:42 technically I think satisfied that last part. I also wasn't satisfied with a standard dunk.
00:48 That's 10 feet. The world record is 12 feet. But I designed these to go up to 16 feet. I really
00:55 don't know why. I guess I have a thing for absurd basketball stuff.
00:59 Although in retrospect I should have stopped at regulation height, trying to go as high as I
01:08 possibly can made things exponentially more complicated and it's also really dangerous.
01:13 My initial idea was some kind of scissor mechanism like you'd see on one of these lifts.
01:22 It has a bunch of linkages that kind of expand like an accordion when it's pushed by this
01:26 hydraulic ram. And I can even do a record-setting dunk in this.
01:30 Unfortunately this lift weighs about 3,000 pounds so I can't attach to my foot and take a step with
01:38 it. But I was thinking maybe I could miniaturize this concept into something much lighter that
01:44 barely works. But doing the math I don't see any way to make this where it doesn't just bend and
01:49 break. But then I just happened to find the answer at the hardware store. This is a collapsible ladder.
01:55 It goes from a really small size to a really long ladder and it's strong enough to hold a person,
02:01 but it's also really light and portable. This is exactly what we're looking for. If we just
02:05 remove this middle part we'll have two telescoping poles that we can build our stilts around.
02:11 Then if we connect them to our feet and make them expand we have go-go gadget legs. Although at the
02:18 moment this is just kind of a dead fish and we need to find a way to make these expand automatically.
02:23 I want the legs to extend by themselves, to pull themselves up by their bootstraps.
02:28 And my best idea, which I kind of hate and kind of love, is this. Air. This is called an air cylinder
02:35 and it's kind of a mini version of what I'm thinking about. So this is a sealed tube and
02:39 inside there's a rod and if I put air behind the rod it's going to shoot out like this.
02:47 And if you think about it the segments of this ladder look a lot like an air cylinder.
02:51 That's inside of an air cylinder.
02:53 Inside an air cylinder. Air cylinders all the way down. If I could just make this air tight,
03:04 putting air into one end should make the whole thing expand, lift me way up into the air to do
03:09 an epic dunk. Although saying just make it air tight is an extremely loaded statement,
03:14 which engineers love to do. Just make it lighter, faster, and cheaper. Just compute the optimal path
03:19 that visits each city once. Just split the atom. It's so tiny how hard could it be? We just need
03:25 to make it airtight except for it's full of holes. There's going to be a million seals in this and a
03:31 bunch of them are going to move. Every single one of these tubes has to be able to slide while
03:35 staying airtight and I think doing that reliably is going to be the hardest part. My general
03:40 strategy is going to be to put a rubber ring around each of these tubes and squeeze it tight against
03:45 the tube so that it's sealed airtight but the tube can still slide underneath this ring and this is
03:51 called an o-ring. Although the way I've drawn this air can still go up and out up here so we'll need
03:56 another o-ring to seal the top. Let's get it made. Almost all the metal parts can be made on my water
04:03 jet. If you haven't seen this machine before it cuts metal using water. If you want to see how
04:08 it works check out my pencil sharpeners. Man these would have taken so long to machine.
04:14 Machining metal parts is the most work so I try to avoid it
04:18 but there still were a number of parts I had to machine.
04:22 That's all the metal parts now we have to make all of those seals. Every joint requires a custom
04:29 piece so it would be way too much work to machine all these so I'm just 3D printing them.
04:36 These are the pieces that'll hold the o-rings. They hold the o-rings inside these grooves.
04:41 Then they slide onto the ladder and they're held in place with a very special screw.
04:46 Everything has to be airtight so even the screw has a little o-ring on it to seal it.
04:51 All right now we just have to do this for 12 more joints. Putting this all together is really tricky
04:56 because it's very easy to damage the o-rings. That's all the seals for the joints and they
05:02 feel pretty good. Feels like this would be airtight although we also have to seal the ends.
05:07 The little tube touches the ground and so there's kind of a foot that goes on the end of it to seal
05:11 it and then the big hole on the top is sealed by this big complicated cap which has a lot going on
05:17 but the only thing that matters right now is that there's a spot where we can put air in
05:21 to make this thing expand. But there is a very important question here which is what makes it
05:27 stop expanding? Because when we put air into this hole it's going to generate an insane amount of
05:33 force trying to make it extend and at some point it has to stop or it's going to blow itself apart.
05:39 These legs have a range of pistons from a very big one up here to a very small one down here
05:46 and this little one is going to need a lot more pressure to lift me than the big one. It's about
05:51 10 times the pressure which means that when I'm giving it the pressure to make this one expand,
05:56 this one's going to be seeing about a thousand pounds of force trying to pull it apart
06:00 and so the leg has to withstand that otherwise this is just gonna pop apart. There's a plastic
06:07 cap on the top of each of the segments which wedges itself in this sort of circumferential
06:12 ridge on the inside of the tube. My instincts are telling me there's no way this piece of
06:17 plastic will be able to take the forces so we're gonna test it just to see. We're gonna give it all
06:22 the pressure and see if the tube pops apart. I also calculated that the tubes can take this
06:27 pressure without rupturing. Well that answers that question. We need something that's gonna keep
06:36 these from going beyond a certain point. This is hard because there's just no room. We can't even
06:42 start putting holes and stuff because we have to keep it airtight. The initial design that I came
06:47 up with was to use steel cables that would connect each segment to the next one and they would bend
06:52 out of the way when it was collapsed and then stretch tight when they reached their limit.
06:57 But the more I thought about it the more I hated this design so we're not going to do this. I have
07:03 cable for a future project. What I'm going to do is really similar but a lot better. Instead of a
07:09 cable we're going to make a sort of chain out of two pieces of metal. Connecting the segments
07:13 together with this will hold them together and it'll fold down really nicely. All right let's
07:18 make it. I have over a hundred custom metal parts now. Thank goodness I have the water jet because
07:25 machining these would be a nightmare. All of these little rings are how I'm going to mount the chains
07:31 to the tubes without putting holes in them. Rebuilding the legs is not fast though and
07:37 hopefully I don't blow seals much because you have to take the entire leg apart to get to a seal.
07:43 The question now is if this thing can lift me and I add a little foot rest to stand on
07:48 and I only have one because these are very time consuming to make. Ultimately I'll have two of
07:55 them one for each leg but not until we work out the kinks with this one. So if I'm successful
08:01 I'm going to go way up and then fall down and I'd rather not land on my head. So I'm going to have
08:06 an auto belay attached to the ceiling and attached to me. I'll be wearing a harness
08:11 and what this does is it's basically a rope that's automatically pulled up as I go up and if I fall
08:17 it will catch me and lower me down safely the same way that a rock climbing belayer would work.
08:22 Another danger when this thing is fully extended it's going to be way up there. It's really top
08:27 heavy. If it falls over it could punch a hole in the wall which is why I added this tarp to try to
08:33 protect the wall. It could also land on my head. So I have this rope with a pulley that can move up
08:38 but not down. The leg will be attached to this and then if I fall off it'll just hang by the pulley
08:44 rather than falling on me. My last fear is that this thing is going to punch me in the face.
08:49 When I pressurize it it's going to be trying to expand but my body weight's going to be pushing
08:53 it down and if my foot pops off it will shoot up with potentially a lot of force and it could hit
08:58 me in the face. I'm not sure how bad this effect will be so I'm going to do is pressurize it up
09:05 carefully and jump off to see where it goes. Whoa! Yeah we should probably do something about that.
09:14 So here's what we're going to do. We're going to run a cable down the inside of the leg anchored
09:20 to the foot and it's going to go up and attach to a winch and it can expand it in a controlled way
09:26 by unspooling it. Here's the winch and the very smooth cable which seals against the cap where
09:31 it goes into the leg. This lets it slide through the cap without air coming out. It attaches very
09:36 securely to a new metal foot and it winds onto the winch on the side and wraps over this pulley
09:41 so that it goes straight into the leg. I think it's safe to say that standing on the leg and
09:46 just letting it rip is not a good way to test it. Everything happens very fast. I can't tell
09:50 what's going on so I made this roller coaster track that will guide the leg up and down in
09:55 a straight line. This will let me be much more systematic and take things a little bit easier.
09:59 It also should be a lot safer since it's moving in a controlled way rather than shooting off in
10:04 random directions especially not into my face. This air gun is what lets air into the legs.
10:10 To make the testing easier I'm running the winch with a drill. Yes it works!
10:17 You know what? Never mind. This winch design is just terrible.
10:27 Every time the leg retracts it goes slack and gets tangled up and it's really easy to damage
10:33 the line and it gets kinked. Really the only thing I'm trying to solve is this thing shooting up
10:38 uncontrollably and if that's the main problem to solve there's other ways to solve it. Let's be
10:44 real. This is why they make helmets. All right let's see if this thing can lift me.
10:50 So I didn't design the seal fittings right. They're the wrong shape. So I printed a new set
10:57 which we're going to install and hopefully that'll do it. Rebuilding these legs takes so long.
11:03 This is the most painful part of this project for sure. All right let's try it again.
11:12 Unfortunately I designed the seal fittings wrong. They just leak still. So I designed and printed
11:20 another set and hopefully these ones will work.
11:25 So I'm going to try this again.
11:31 I designed the seal fittings wrong. They just leak still. So I designed and printed another set and hopefully these ones will work.
11:42 Did I mention how painful this process is? But I think the seals are good now
11:47 and look how tall these things are. Wow.
11:51 I think we're ready to make the second leg so allow me to present 20 hours of my life in 10 seconds or less.
12:00 We're still going to use the guide rail so I'm modifying it to hold two legs. All right here we go.
12:07 So good it works.
12:13 I still think this ladder is shooting up too fast and so we're going to connect it to an
12:20 auto belay in reverse. This should keep it from shooting up too fast. Let's see how it works.
12:26 That is way better. Now that it's not going to kill me let's try dunking some balls.
12:32 Let's see if we can dunk.
12:36 Easy. Okay so now there's two questions. How high can we go and can we get to the top?
12:54 How high can we go and can I do it without the rail? Let's start by going high before I get injured.
13:00 We're going for 16 feet.
13:02 All right so wow.
13:07 All right on belay you can do it man. So this is about the limit of the legs. It's really slow.
13:23 Come on. Come on. One more. One more. Oh yeah.
13:31 I can't believe I just inflated a ladder to lift me up 16 feet to perform a completely
13:48 fraudulent dunk. What a time to be alive.
13:51 I was doing a bit more testing when the rail got jammed.
14:01 The force of the legs completely obliterated the mount which is really strong.
14:05 This is a great example of why I'm so afraid of these things.
14:11 Let's make sure that doesn't happen again.
14:16 I'm making a new rail guide that's all steel, super strong, and it should be unjammable.
14:22 Basically the same thing as the wooden guide, it's just made of steel.
14:27 And seeing how strong this is makes me more confident so I want to see how fast we can go.
14:32 I upgraded the air delivery system so that we can get more air into these things faster.
14:36 All right we are on belay. A little bit afraid to give it full chooch. Here we go.
14:42 Whoa oh my goodness that is... That was faster than I was expecting. That was freaky.
14:50 All right on belay. Belay is on. Dunking. Dunk on. Full speed.
14:56 It's so good.
15:05 Oh that's crazy.
15:23 This is incredibly fun and it's really cool but I'm not totally satisfied.
15:29 I really want to see dunking with a self-balancing set of legs.
15:35 So I'm going to work my way up to full balancing starting with this.
15:38 I'm attaching the stilts to the cart with a pivot that lets them move side to side
15:42 so I'll have to balance in that direction.
15:44 But they won't let me go forward and back so it's sort of half balancing.
15:50 Let's see if we can do it.
15:50 This ended up being a lot harder than I was expecting.
15:57 I ended up spending multiple days practicing and then sleeping on it
16:01 to try to make it muscle memory.
16:04 Ow what the...
16:06 And after a lot of practice I can do this.
16:08 There we go.
16:10 Dunked.
16:14 That was pretty smooth.
16:17 Maybe I am learning to balance on these things.
16:20 We are now disconnected from the rail. Let's see if we can balance in all directions.
16:25 I can't even balance on the ground. I don't know if that's gonna happen man.
16:31 Well that was prophetic.
16:33 All right here we go again.
16:34 I spent hours trying to balance on this.
16:39 I slept on it to see if I could get better and I didn't.
16:42 Oh there is no way I'm balancing front to back but that's okay because I just realized I'm a moron.
16:51 Why am I trying to walk around on peg legs?
16:55 I don't walk around on my heels. I walk on feet.
16:58 I made some size 11 feet for it which just like my size 11 feet should help it balance front to back.
17:05 We are no longer attached to the rail.
17:08 I've got a climbing rope with a one-way pulley which should keep it from tipping over and
17:12 slamming into my head or the floor but it's not actually strong so it's not helping me balance.
17:27 I didn't fall.
17:28 This still isn't really fair. The stilts are connected together by this beefy frame
17:35 and it makes it easier and they're not stilts. I can't walk in them so we have to do it without this.
17:40 I could totally walk in these if they were connected to my feet.
17:45 I designed these to do that but it's way too dangerous so I'm not doing it.
17:49 All right here we go.
17:52 No no no no no no no no no no no.
17:56 I'll tell you what you really wouldn't want to get in front of these things.
18:08 Man that's so scary every time.
18:13 We're getting there. I mean we're getting there sort of.
18:17 This is really hard and really sketchy.
18:20 We're gonna keep trying but before we do that if you're wondering how I'm able to make something
18:24 like this and have it mostly work and not punch me in the face it's really because I've taken
18:30 the time to develop a theoretical understanding of how things work so I can predict what pressure
18:36 do I need, is this thing going to explode, what are the forces going to be before I've built
18:41 anything and then I can design it so it'll probably work. Usually.
18:45 And it's not magic it just takes a bit of time and effort to learn it which is why I'm a huge
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20:13 All right it's time. We have to do this. So here we go. 12 feet one inch. World record by the nerd.
20:20 Totally legal. Totally regulation. Here we go.
20:23 All right we are just going for it.
20:28 Yes! Yes! It works! Oh my that is scary.
20:40 [Music]
20:47 Finally full dunk at speed with stilts with no help. We did it. It's the only time I'm
20:55 doing it because that's way too sketchy. I need to go sit down. Thanks for watching.
21:01 [Music]