Everything About Disc Golf Aerodynamics - Smarter Every Day 313

0:00 Hey, it's me, Destin.

0:01 Welcome back to Smarter Every Day.

0:02 This is my favorite disk golf course in the entire world,

0:05 and I have a physics question for you today.

0:08 Let's go figure it out.

0:09 Every time you throw a disk golf disk, it curves.

0:13 Every time there's a curve, it curves.

0:19 Do you see that curve?

0:20 Even a short throw like this.

0:22 Let's see if I can hit this.

0:24 Okay, it was subtle, but that disk curved on the way to the basket.

0:29 Today, we're going understand why.

0:31 It's a thing I've been wanting to figure out for a long time,

0:33 but it's very, very complicated.

0:36 And we're going to explore this three ways.

0:38 The first thing we're going to do is we're

0:39 going to go talk to some professionals in Finland.

0:42 The Disk Golf World Championships happened in Finland for the first time,

0:45 we're going to go meet these pros and ask

0:48 them what's going on with this curvy thing, okay?

0:50 The second thing we're going to do is we're going

0:52 to meet some tech guys that integrated some technology into a disk,

0:55 and it helps us understand the vocabulary

0:58 and the dynamics and kinematics of how the throw happens.

1:02 And once we understand all that, we're going to go meet the professor.

1:06 Dr.

1:06 Johnny Potts, did his PhD dissertation on the aerodynamics of disk flight,

1:12 and he's going to put it all together for us.

1:15 So if you watch this video,

1:16 you and I are going to learn together the aerodynamics

1:19 of a disk in flight and why that curve happens.

1:23 This is going to be awesome.

1:25 Let's go get Smarter Every Day.

1:29 Now, in the last video, when we talked about disk golf,

1:32 we talked to Brad and Chad.

1:34 These guys own a company called MVP Disk Sports.

1:39 They manufacture disk golf disks right here in America, which is really fun.

1:44 So we went and learned how they do this with robotics,

1:47 and it's an amazing thing.

1:48 But we also learned about how they care about the geometry

1:52 and the balance of these disks and all this stuff.

1:54 It's amazing, right?

1:56 So MVP has sponsored this video.

1:59 I want to be very clear about that.

2:00 Usually, when a company sponsors a video like this, there's

2:03 a code or a URL or something, go buy this thing.

2:06 Brad and Chad did not want that for this video.

2:08 They just want people to love disk golf.

2:11 And the thought is, because they're nerds,

2:13 if you nerd out with the physics of throwing a disk,

2:16 you're going to enjoy disk golf as well,

2:18 and the whole community is going to rise.

2:21 And I thought that was really cool.

2:22 So big thanks to MVP for sponsoring this video.

2:25 So to start our journey of understanding of disk golf physics,

2:28 let's go to Finland.

2:29 Now, when I got off the plane, I was greeted by an old friend,

2:32 Jussi from Kamerastore, who later tagged me up with Juho from Kamerastore.

2:37 These are buddies of mine from Finland from a previous episode,

2:39 if you've seen that.

2:40 The reason we're in Finland is for the first time ever,

2:43 the professional disc golf association world championships

2:46 is being held outside of the United States.

2:49 It's being held in Finland.

2:51 Finns absolutely love Disk Golf.

2:54 So the day before competition,

2:55 I went to the course and I met up with two of MVP's sponsored athletes.

3:00 The first is Simon Lazotte, an absolute legend in the world of disk golf.

3:05 And the second one was Eagle McMahon,

3:07 who has an incredibly strong drive right now.

3:10 He's on top of his game.

3:12 These are two guys that were practicing the course,

3:14 the the day before, and they let me jump in with them.

3:17 [S] This is the most treacherous hole in the hole course, actually, too.

3:20 [D] Is it really?

3:21 [S] It's the infamous Island hole.

3:22 You got to lay one up between the stakes and then shoot

3:26 over across the out-of-bounds to a little island that is pretty small.

3:31 If you miss it, you have to keep re-throwing

3:32 and get penalty strokes for each shot that misses.

3:35 This first one is all about just putting yourself in position.

3:37 Try to throw a big right to left swing to the fairway down there.

3:43 [D] Sweet.

3:46 [S] Little too wide, but that's going to be okay.

3:54 Yeah, right there.

3:54 Not bad.

3:55 [D] Okay.

3:57 You're doing the same, Eagle?

3:58 [E] Yeah, I'm going out to the right just

4:00 trying to get it just past that gravel path.

4:02 [D] Got it.

4:07 [S] That's better.

4:14 [D] Got you.

4:15 All right, so you set up over here.

4:18 [S] Exactly.

4:19 Everything inside these wide stakes is considered inbound,

4:22 and the fairway goes all the way up to here.

4:25 If you wanted to, you could lay up another

4:27 shot to there to make the island shot shorter.

4:30 Now you're just faced with a decision to make.

4:32 If you want to go for it and try

4:34 to stick it on that little half circle island green,

4:38 anything outside of the hay or long over the path is out of bounds.

4:44 [D] If you go OB, then you come back to this spot?

4:47 [S] Well, I get to advance to the OB line,

4:49 and then I have to try again from there until I say [D] -Dang.

4:52 [S] This hole, obviously, is wide open,

4:54 so wind comes into play more than in other holes.

4:57 This one's all about angle control and distance control.

5:00 Roll.

5:00 I'm going to throw it pretty high and try to spike it

5:04 down into the green so it doesn't skip or anything or roll.

5:07 It just sticks right there.

5:13 That's a bit too high, too left.

5:15 Sit.

5:17 So you made it?

5:18 No, that's out of bounds by a foot.

5:20 Are you serious?

5:20 Yeah.

5:21 I would basically have to.

5:28 [D] I'm going to come watch Eagle.

5:39 [S] Sit.

5:41 Good shot.

5:43 [D] Holy cow, dude.

5:44 [S] That's perfect.

5:45 [D] What the heck, man?

5:46 [E] That's what you'd want in the tournament.

5:48 [D] What the heck, dude?

5:54 [S] That's an easy birdie right there for him.

5:57 I'll get a double bogey.

5:58 Everyone who that plays disk golf loves a specific course.

6:02 Normally, they're home course.

6:04 So what you're about to see is a total freak out moment

6:07 for me because my favorite course is Sparkman Park in Hartzell, Alabama.

6:12 It's great.

6:12 So just watch this exchange.

6:14 And if you play disk golf and you have an affection for a certain course,

6:18 you're going to know what I'm feeling here.

6:20 [S] Have you ever played disk golf?

6:21 [D] Have I ever played disk golf?

6:23 Yeah.

6:24 Oh, you don't know about Hartzell, Alabama, dude.

6:26 [S] I don't.

6:27 [D] Sparkman Park, you've never heard of Sparkman Park in Hartzell, AL?

6:30 No, it's internationally known.

6:31 I can't believe you guys are [E] I played it.

6:33 I played a tournament out there.

6:34 [D] Did you really?

6:35 [E] Yeah.

6:35 [D] In Hartzell?

6:36 [E] Yeah, I won the Monster in 2020.

6:38 My girlfriend's from Huntsville.

6:39 [D] Shut up, man.

6:41 No way.

6:42 [E] Yeah, I've spent plenty of time in Huntsville.

6:45 [D] Dude.

6:45 [E] Bronze Springs.

6:46 [D] Bronze Springs, Huntsville, and then Hartzell is the...

6:49 [E] Yeah.

6:49 [D] Oh, you know-Oh, yeah.

6:51 So it's the two put together.

6:52 [E] Yeah.

6:52 That's the monster.

6:54 I haven't played this typical course at Hartzell.

6:57 I've just played the tournament layout down there.

6:59 [D] Gosh, man.

7:00 Simon, I know you're new to disk golf,

7:01 but you don't know how big of a deal that is.

7:04 I'm joking, man.

7:05 I know.

7:06 [S] No, it's great.

7:07 If someone played my home course, I got excited.

7:10 [D] That's great.

7:11 Simon, Eagle.

7:12 I apologize for epic levels of cringe.

7:15 I apologize to myself because I'm not going to forget that.

7:18 And also, I do owe you an apology.

7:20 I took the wrong micro SD cards on this trip, so the audio is pretty rough.

7:25 I apologize for that in the video.

7:27 Anyway, sorry for the cringe.

7:28 Here we go.

7:34 [S] That's ideal.

7:35 I'll come back left, a little skip.

7:39 That's going to be right about 10 meters.

7:40 [D] So it went left, then right, then left.

7:43 [S] Yeah, this is a bit under stable.

7:46 That's when it has a tendency on a right-hand

7:48 back-hand throw to turn to the right.

7:51 But naturally, with clockwise spin,

7:53 every disk wants to fall left when it slows down.

7:56 So we're going to assume something called a right-hand

7:59 back-hand throw when we're looking at the physics.

8:01 This is my right-hand.

8:03 It's the dominant hand I use to throw a disk.

8:05 So a right-hand and back-hand throw is like this.

8:08 And when you do that, if you were to look from the top down,

8:11 a bird's-eye view, you would see that the disk is rotating.

8:15 For flying that way, the disk is rotating clockwise.

8:19 If you were to throw it with your left hand, back hand,

8:21 the disk would be rotating counterclockwise when viewed from the top.

8:25 So everything we're going to do,

8:27 we're going to assume a right-handed back hand throw

8:30 because that allows us to talk about the physics.

8:33 Everything works.

8:34 For left hand, it's just backwards.

8:36 Okay, let's go learn.

8:37 [E] What you just saw Simon do,

8:39 he threw a back hand shot, which has a clockwise spin,

8:43 and the disk is going to go out and naturally want to fade to the left.

8:48 To throw a forehand, you're going to put a counterclockwise spin,

8:51 and it's going to want to fade to the right.

8:54 So the best players in our sport are very proficient in both forehand

9:00 and backhand because you're able to shape

9:03 different shots depending on what the fairway needs.

9:07 Playing into the hillside generally is a little

9:09 bit better coming in on a forehand angle,

9:12 so that counterclockwise spin is going to help it stick better in the hill.

9:16 [D] Meaning it's going to die when it hits because of the rotation.

9:18 [E] It's going to die when it hits, exactly.

9:25 [S] Perfect shot.

9:29 Nice.

9:31 [E] Now I'm going to try throwing a backhand with a putter,

9:34 which a putter is a slower disk that won't go as far,

9:38 but it has more drag in the air,

9:40 so it's going to want to fall quicker and sit softer.

9:50 [S] Perfectly played.

9:56 [E] I like that.

10:00 [D] You just shot a putter, 459 feet?

10:05 [E] It helps because you have elevation on your side.

10:07 [S] He has a top three fastest arms in the world.

10:10 [D] Does he really?

10:11 [S] I'd say so.

10:12 [D] You just threw a putter, 450 feet?

10:14 [E] I mean, that's what 18 years of playing gets you.

10:18 [D] How old are you?

10:19 You're like 19.

10:20 [E] I'm 27.

10:22 [D] That's crazy.

10:24 [E] Yeah, I started playing when I was nine years old.

10:26 So what we're going to do now is

10:27 we're going to learn the vocabulary that they use.

10:30 And the interesting thing about these words is

10:32 they were born out of this utilitarian need

10:34 to have a word for the thing that happens when you do this with the disks.

10:39 So what we're going to do is we're going to go talk to them,

10:42 ask questions, and we're going to learn

10:44 the vocabulary of professional disk golf players.

10:47 So what I want to know, Simon, is how you think about the angle that you throw

10:50 at and the power and the spin and all that.

10:53 Right now, if we were going for that cone

10:54 that's way down there that I can barely even see,

10:57 and you wanted to lay it up right in that.

11:00 I know that as you throw a disk, it goes,

11:03 and at some point it turns, and it turns a different way.

11:06 How does all that work?

11:07 [S] All right.

11:08 As professionals, we try to figure out what is

11:11 the most repeatable way to get to our target.

11:15 There's something that we call a one angle shot,

11:18 is where the disk actually only flies on one angle.

11:22 The most natural angle for a back-end throw is this right to left diving hyzer,

11:28 what we call it, where a disk goes up and then falls down to the left.

11:32 The most repeatable thing is to throw a hyzer

11:35 with an over stable disk because the room

11:37 for error is very big because you can be

11:40 slightly off angle and miss your shot a bit,

11:43 but the result will be almost the exact same.

11:45 [D] What does over stable mean?

11:47 [S] over stable is the disc's tendency to basically

11:51 dive to the ground depending on which way it's spinning.

11:55 For a backhand throw for right-handed, it's spinning clockwise,

11:59 which means it wants to fall left.

12:01 For a forehand, it's counterclockwise and it wants to fall right.

12:04 [D] Over stable, if I throw, it falls towards my belly button.

12:09 [S] Correct.

12:10 [D] Okay.

12:10 [S] Basically, just with reading the wind

12:13 direction and from experience how your disk flies.

12:16 You basically visualize a line where you want the disk to go,

12:20 and then you just throw it up on the one angle on the hyzer,

12:23 and it should just consistently dive to the same spot.

12:26 [D] Can you show me what that looks like?

12:27 [S] Yeah, absolutely.

12:28 Very easy.

12:30 I'm just going to show you three examples.

12:32 First, I'm going to show you what I would

12:34 throw in a tournament as my most consistent shot, which is, like I said,

12:39 a backhand hyzer shot where I will aim about 30 feet right of the cone,

12:44 maybe 40 feet, throw the disk about 40 feet high, and have it dive left.

12:49 [D] What angle are you going to throw the disk at this way?

12:51 You're having to think about this angle, this way, and this angle, right?

12:56 Yeah.

12:57 I've been doing this my entire life, so I really don't try to think about it.

13:01 [S] I just do it.

13:02 [D] Okay, just do it.

13:03 Just do it.

13:03 I'm going to watch.

13:04 [S] I pick a spot in the sky,

13:06 and then you want to line up your run up and your body to that spot,

13:10 and then just match the angle with your hand and arm.

13:14 [D] You're going to try to have it die on the line with the cone?

13:16 Correct.

13:17 Okay.

13:17 Here we go.

13:21 [D] Very high.

13:22 [S] Yeah, a bit higher than I wanted,

13:23 but you can see it's diving right on the cone.

13:25 [D] Dude, you almost hit the cone.

13:27 You almost hit the cone, dude.

13:28 What I just learned is that if you're trying to get on a line right here,

13:32 you want to hit over here and have it bounce over.

13:35 So you're planning all that.

13:36 [S] Correct.

13:37 [D] Okay.

13:38 [S] Yeah, I'm going to show you a different shot now.

13:39 This is actually a putter, which is as straight as a disk can fly.

13:45 Just the way the profile works,

13:47 it doesn't have much tendency to dive in either direction.

13:50 So this is more like a frisby.

13:51 I'm going to try to throw just right straight at it in a straight line.

13:55 We call it the easiest shot in disk golf, even though that's just a joke.

13:58 It's the hardest shot in disk golf.

14:00 Throw it dead straight.

14:01 Technically, this should just go dead straight.

14:04 You can see very little fade left at the end, but compared to the driver,

14:12 basically just wants to go straight and dive down [D] Why

14:15 did the putter stay so much straighter compared to the driver?

14:18 [S] That is a great question.

14:19 [D] You just know it does.

14:21 [S] That's just what it does.

14:22 [D] Okay, show me more.

14:24 [S] Now I'm going to do the exact opposite of what I did.

14:27 This would be a very technical throw, which this is a very under stable putter.

14:32 The reason I know it's under stable is because you can

14:35 see this nose of the disk is all the way bent down.

14:37 Then the parting line between the two molds,

14:39 which is the bottom and the top, meets very low on the profile.

14:44 [D] That makes it under stable?

14:45 [S] This makes this disk really want to go left to right.

14:48 [D] Under stable means it goes behind you.

14:51 If I'm throwing, it doesn't go where my belly button goes, it goes back.

14:55 That's under stable.

14:56 [S] Under stable means the disk has a tendency to turn over,

14:58 and if it turns If it's too much,

15:00 it'll actually hit the ground and start rolling.

15:02 [D] You're going to throw the same shot and we're going to watch it fade left.

15:04 [S] Correct.

15:05 [S] I'm going to aim about 30 feet left of the cone,

15:07 and the disk will naturally just drift left to right.

15:10 Okay.

15:11 [D] Wow.

15:19 [S] A little short, but the line was good.

15:21 [D] That's a good shot.

15:22 Okay, so that's under stable and over stable.

15:24 [S] Yes, correct.

15:25 [D] That's amazing.

15:25 [S] The second one was we consider stable.

15:28 Stable means straight, over stable means right to left,

15:30 under stable, left to right.

15:31 [D] So the first throw was over stable.

15:33 [S] Yes.

15:34 [D] The second throw was stable.

15:35 [S] Yes.

15:36 [D] And the third throw was under stable.

15:38 [S] Correct.

15:39 [D] Dude, I played disk golf as an amateur for a really,

15:43 really long time, and I know that was simple for you.

15:45 That was very good.

15:47 [S] I'm glad.

15:48 Okay, now, right-hand, backhand, we have over stable,

15:52 we have stable, and we have under stable.

15:55 Now, let's go to the next level deeper with Eagle,

15:58 who's going to teach us a couple of more words.

16:00 Eagle.

16:01 I just learned about under stable, stable, and over stable.

16:06 [E] Okay.

16:06 [D] I guess I should say it backwards.

16:08 Over stable, stable, under stable.

16:10 What I want to know is how does… There's two angles that you throw.

16:15 Which one is… There's a word for this.

16:19 What's this and what's this?

16:21 [E] This is a hyzer.

16:23 [D] Okay, that's a hyzer.

16:25 [E] This is flat.

16:26 [D] Flat.

16:27 [E] And this is an anhyzer.

16:28 [D] Anhyzer.

16:30 [D] So hyzer is like, if I'm throwing it, I want to fall into the ground.

16:33 [E] Yes, exactly.

16:34 A good way to picture it is think of a hula hoop around you.

16:37 If you want to throw a hyzer shot, you're going to tip forward.

16:42 The front of the hula hoop is going to go down and the back is going to go up.

16:45 [D] So hula hoop, hyzer.

16:47 So hula hoop hits the ground on a hyzer.

16:48 [E] Yes, exactly.

16:49 So you lean forward.

16:51 And then on an anhyzer, you're going to be leaning slightly back.

16:57 So that front part of the hula hoop is going to go up,

16:59 and the back part is going to go down.

17:03 I'll use these two stabilizers, which [D] Are they the same disk?

17:07 [E] They're virtually the same disk, so you'll be able to see how they function.

17:12 [D] Okay, so what are you trying to do now?

17:15 [E] Let's throw a hyzer first.

17:17 With this disk, I'm going to throw it out to the right on a hyzer.

17:21 Since this is already a fairly over stable disk,

17:24 it's going to want to fall to the ground and hyzer pretty quickly.

17:30 [D] Okay.

17:35 Got it.

17:37 [E] Okay.

17:40 Now I'm going to throw the stabilizer on a slight anhyzer.

17:46 And with this being a slightly more over stable disk,

17:51 it's going to want to gradually fight back to a hyzer.

17:58 [D] So we're going to get an S out of this?

18:01 [E] Potentially.

18:02 [D] Okay.

18:02 [E] Potentially.

18:03 It depends how you want me to throw it.

18:05 I could throw it a little bit.

18:06 It depends on how much anhyzer I put on the disk.

18:10 [D] Give me an S.

18:11 So you're going to use anhyzer and over stability to create an S in the throw?

18:16 [E] Yes.

18:17 [D] Okay.

18:17 Yeah.

18:17 Show me that.

18:18 [E] I'll show you the best of my ability.

18:23 So you saw a little bit of that S curve.

18:27 [D] Yeah, it did.

18:29 Interesting.

18:30 [E] It's easier to throw an S-curve with a more

18:33 over stable disk because you're able to, what we call, force over on the disk.

18:39 And with an over stable disk, as it gets through its flight,

18:44 it's going to you're going to gradually start panning out and then

18:47 fighting back into a hyzer with the natural stability of the disk.

18:52 [D] Why would you do that?

18:53 Why would you want to do that?

18:54 [E] Because it depends where you're at on the course.

18:57 Think of hundreds of trees in front of you the fairway,

19:01 you have to start it out left and bring the shot from left

19:05 to right and get as close to the basket as you can.

19:09 There becomes a whole lot of creativity where you see the basket,

19:13 you're like, Okay, how I'm going to get there?

19:17 Am I going to throw a hyzer that's going to gradually

19:20 flip up with an under stable disk and push forward?

19:24 Or am I going to want to take a flex shot where I force

19:29 an over stable disk on an anhyzer that's going to gradually pan out and fade.

19:34 A lot of it depends on the ground.

19:38 Is it going to skip?

19:39 Is it on a hill?

19:42 Is there water in front or behind the basket?

19:45 So a lot of it comes down to is

19:48 tactful decision making in the moment where you're at.

19:51 And we play practice rounds at these courses,

19:54 but it's really hard to be hard to know exactly where we're going

19:57 to be until we're in that position [D] And you got to do it.

20:01 [E] Yeah.

20:01 Okay.

20:01 Already with the tendency of certain disks to be stable or under stable,

20:07 and then combine that with the ability to throw hyzer or anhyzer,

20:11 you now have the ability to morph how that disk will fly down the fairway.

20:16 So we're getting a lot of tools in our toolbox that we

20:19 can use at any point on a disk golf course, right?

20:22 We're going to talk to Simon and the Eagle again,

20:24 but we're about to meet a new player on MVP's team,

20:27 Jeremy Koling, known throughout the sport as Big Germ.

20:30 He's got a really strong forearm, and he's a great communicator about the sport.

20:34 Show me how a forehand works.

20:36 [J] All right.

20:36 Well, so everything that I ever did as far as athletics,

20:40 if I was throwing something, was using this motion.

20:43 So when I found the sport of disk golf, I didn't know what this was.

20:47 So I developed my entire game early on around just learning how to do this.

20:52 You're bringing the disk back, and then you're using your wrist and your elbow

20:57 coming through your hips to create this fulcrum, and you're going, wham,

21:01 and you're trying to put basically as much spin as you can.

21:05 My forehand, my spin rate stays pretty consistent,

21:10 whether I'm throwing a short shot or a long shot.

21:13 The thing that really is changing is how much pressure

21:15 am I putting in with my legs when I'm planting,

21:18 and how fast my elbow comes through my hip.

21:22 [D] Yeah, I guess that's right,

21:23 because all of the force has to come from the ground.

21:25 [J] Starts from the ground, it goes all the way up from there.

21:27 [D] Really?

21:28 [J] Did they teach you the X-step?

21:30 [D] No.

21:30 What's the X-step?

21:31 [J] The X-step is something that we teach people playing disk golf.

21:34 When you learn the mechanics of the throw itself,

21:38 you're usually teaching people early on the mechanics just from a standstill.

21:43 But once they get the basics of the throw down,

21:45 and you want to teach someone how to throw a little bit farther,

21:49 you teach them the X-step, which is getting your body from this forward

21:53 position where you can see your target,

21:57 to getting your body into this perpendicular position

22:00 where your back foot crosses over your front foot,

22:05 and simultaneously, before this foot even lands,

22:08 you're moving this foot forward into a plant position,

22:11 and now your body and your hips are turned

22:13 to your target so you're able to reach back,

22:16 use your legs to push into the throw,

22:18 and that's how you get your entire body from your ankles to your knees,

22:22 your hips, your shoulders, your elbow, everything into the throw,

22:25 as opposed to just your arm and your upper body throwing the disk.

22:29 [D] It's all coming from that back leg.

22:31 [J] It's all starting from the ground up.

22:32 [D] But you're getting velocity by doing the X-step.

22:34 [J] You're not only getting velocity,

22:37 you're getting speed, but you're also getting this twisting,

22:40 propelling, almost like you're squeezing or you're twisting this rubber band,

22:43 and then you let loose in this rubber band on coils,

22:46 and it creates all this power.

22:48 [D] Can you show me?

22:49 [J] Sure.

22:53 We have a relatively short soccer field here,

22:55 so I'll just grab a putter and give you an idea here.

22:59 We'll try to go to somewhere near that cone, and I'll go in slow motion.

23:03 So that's the idea of the step is that I

23:05 want to keep my body in a straight line.

23:08 If I start going out here and back here,

23:11 then I'm losing whatever I was trying to get into that throw.

23:14 [D] Oh, momentum.

23:15 So you're trying to get linear momentum.

23:17 [J] We try to go from slow to fast.

23:19 [D] Okay.

23:20 [J] Right?

23:20 So we get our stable base.

23:22 I got the cone lined up.

23:24 Now, I'm going to move a little bit to the left

23:26 because if I want to throw to that cone, I'm going to have to aim a little bit

23:30 right of the cone because the disk is naturally,

23:32 for a right-hand, back-hand throw, going to fade towards the left.

23:35 [D] Because it's over stable.

23:36 [J] Because all disk have a little overstability in them.

23:39 It's just the amount of the overstability varies from disk to disk.

23:43 Sometimes, if a disk is really under stable, and if I do want it to go left,

23:47 I can make it go left by putting more down angle on it.

23:50 But for this shot, I want to basically aim

23:52 towards that right cone that you see in the background,

23:55 and the disk will just naturally finish to the left.

23:58 Okay.

23:58 All right, so we'll do our run up here.

24:08 [D] Wow.

24:09 Yeah, and so you were far more linear than I do.

24:12 I just play for fun, but I'm all over the place.

24:16 [J] So that's just going to slow you down.

24:17 And anytime you have all these moving parts,

24:19 you want to eliminate the unnecessary, right?

24:22 You want to eliminate anything that can just

24:24 add extra steps that doesn't actually serve you.

24:26 So I try to keep things as simple as possible.

24:29 And if we're talking about beforehand,

24:31 I take all the fundamental ideas of the right-hand,

24:34 backhand X-step, and I just flip it.

24:37 I reverse it.

24:38 Right, left.

24:40 Then I'll bring this right foot semi-behind the left foot.

24:43 But before it hits the ground, my left foot is getting into my plant position,

24:48 and the benefits of the forehand really kick in right here.

24:52 Because what we're doing with the forehand,

24:53 instead of the backhand, where we're reaching away from the target,

24:56 if I'm throwing this direction,

24:58 my head has to be over here, and then I re-address.

25:02 With the forehand, I can keep my head locked in on the target the entire time,

25:06 so my head doesn't have to actually swivel at all.

25:09 [D] Which one can you throw farther, forehand or backhand?

25:11 [J] You can throw the backhand a lot farther.

25:12 With more contact points on the disk like you have here with the back hand,

25:16 you get the four finger pads on the disk.

25:18 The way that you're pulling through here and finishing

25:21 your follow through almost back in the same place,

25:24 you get like 360 degrees of rotation.

25:26 With the forehand, you're not even reaching straight all the way.

25:31 You're reaching back about here.

25:33 I would say about, if this is 90 degrees,

25:35 you're looking at about 110 degrees here,

25:37 and you're following through forward and you're releasing here.

25:39 So 110 degrees of rotation versus 360,

25:42 you could understand the forehand doesn't quite get you there.

25:46 All right, let's throw it.

25:52 [D] Oh, wow.

25:52 And he just brought it in.

25:54 Right in front of it, man.

25:55 That's cool.

25:55 Dude, okay.

25:56 Thank you very much for teaching me about a forehand.

25:57 [J] Of course.

25:58 My pleasure.

25:58 [D] Yeah.

25:59 So the physicality of disk golf is interesting

26:02 because there's a human to physical object interface,

26:05 and there's a certain intelligence or experience associated with that, right?

26:11 Remember, these are some of the best athletes in the world at this sport.

26:15 What you're about to see blew my mind.

26:17 Their ability to understand what this disk can

26:20 do just by feel is off the charts.

26:24 [J] If I have a disk that I want

26:26 to know definitively exactly how it's going to fly,

26:29 I would give it to Eagle first.

26:31 He could hold a disk behind his back with any brand ever made,

26:34 and he's going to tell you, if he doesn't get it right in the first guess,

26:37 he's going to get it right in the second guess.

26:39 And that's impressive because there's tens of thousands

26:41 of different [D] He understands what the disks are?

26:43 [J] And he could tell you what plastic is.

26:45 [D] Are you serious?

26:45 [J] This guy is a savant, for sure.

26:47 [E] To a certain degree.

26:47 [D] Eagle, turn around.

26:48 We got to...

26:49 Okay, put something in his hand.

26:50 Oh, this is no.

26:51 Is this real?

26:52 [J] If you do an MVP disk, this is going to be easy.

26:53 This is no problem for him.

26:56 [D] He's going to know what that is.

26:57 [J] Oh, for sure, without question.

26:58 Give him three 3 or 4 seconds.

27:01 [E] That's a detour.

27:02 [D] What?

27:03 Are you serious?

27:05 [J] What color is it?

27:06 [E] It's orange.

27:08 [J] If you get this one, I'd be impressed with this one.

27:12 [E] I'm between two disks.

27:13 [J] Alright say them.

27:15 [E] Excite or Teleport?

27:17 [J] It's a teleport.

27:18 [D] What?

27:19 That's nuts, dude.

27:25 [E] Trail.

27:26 [D] Shut up, dude.

27:27 [J] We can grab a disk and we can feel right from the get-go,

27:30 whether it's going to be something that we like or something

27:34 that we haven't had a history of liking disks that feel like this.

27:37 Maybe they're a little bit soft on the shoulder,

27:39 which is where the disk starts to rise from the outer edge to the dome.

27:43 So this is a disk that actually Eagle gave

27:45 to me when I joined MVP earlier this year.

27:47 This is a 14.5 speed, which means it's a really fast distance driver.

27:52 I knew as soon as I got this disk in the mail that I was going

27:55 to fall in love with it because right here [D] Because Eagle gave it to you.

27:58 [J] Well, A, it was a gift from Eagle,

27:59 and I knew that he wasn't going to steer me wrong.

28:01 But B, because right here, this is the shoulder area we're talking about.

28:04 It's the area that's right above the bottom of the rim, the rim edge, right?

28:11 Right here, when our thumb goes in that area there,

28:14 whether the disk if the dome sags down or if the dome continues

28:17 to rise on a very consistent plane and it creates a nice dome,

28:21 I know that this is going to have a lot of loft,

28:23 it's going to have a lot of speed and over stability,

28:25 which is something that a player with a lot of arm

28:28 speed would need to get the most their flight with the driver.

28:31 This is something that immediately I grab this disk,

28:33 I do this little thing here, which all disk golfers do.

28:36 We pop the dome down, we feel how much [D] Do you really?

28:38 [J] Oh, yeah, absolutely.

28:39 [S] Yeah, I mean, feel is a huge thing in disk golf,

28:42 and especially for the pro players.

28:44 The second we touch a disk, we know if we're going to end up using it or not.

28:48 Love it first touch is probably a thing.

28:51 I mean, I would totally agree here.

28:53 You hear that?

28:54 That's good.

28:56 We call it the heartbeat of a disk.

28:57 If it has that as a distance driver,

28:59 it just means it'll go with those extra 50 feet that we need.

29:03 [D] Because it's strong?

29:04 [J] Because this dome and the way it shapes

29:07 up right here and it goes perfectly like a...

29:12 [D] The profile?

29:12 [S] The profile is just this perfect shape where if you

29:15 push down and you get this popping sound, for some reason,

29:18 that means the disk just wants to keep flying and adds glide,

29:22 and it just doesn't want to get to the ground

29:25 as fast as a flat disk, for example, would.

29:27 [D] One question I think most people have is what effect spin have?

29:31 If I'm throwing a...

29:34 This is a driver, right?

29:36 If I'm throwing this and I'm spinning it really

29:38 hard versus if I don't spin it a lot,

29:40 when you guys threw up there in the practice,

29:43 I heard your fingers pop as you let go.

29:45 I've never heard that before.

29:47 [S] We call it snap.

29:49 [D] That's called the snap?

29:50 [S] Yes.

29:51 [D] Teach me about spin.

29:53 Well, from the way I understand it,

29:55 the faster something spins, the more stable it flies.

30:00 I'm not talking about over stable,

30:01 which means a whole different thing in disk golf.

30:02 But something that flies with the most spin will basically have, I think,

30:07 the most lift and fly the most consistently on whatever angle you release it.

30:12 [D] So it's gyroscopically stable?

30:14 [S] Correct.

30:15 [D] So you've got the aerodynamics,

30:17 but you also have a gyroscope thing going on.

30:20 Is that right?

30:21 [S] Yes, but I'm not exactly sure if...

30:23 Do you think any disk golfer adjusts their spin rate on a throw,

30:27 or is that something we don't really tap into?

30:29 [J] I think that's something that we do unconsciously or subconsciously.

30:32 [D] Eagle's thinking things.

30:34 [J] Unconsciously.

30:35 We're definitely conscious when we're doing it.

30:37 [E] For example, there's a bunch of different grips that you can use.

30:40 So there's what we call a power grip,

30:43 where you're putting four fingers underneath the rim,

30:46 and that's ripping out of your hand with a higher spin rate.

30:53 For a put, a lot of people will fan their fingers out,

30:57 and that's going to produce less friction on the disk, creating less spin.

31:02 In a way, for me, for example,

31:05 when I'm throwing a distance shot, I'm using a four-finger power grip.

31:09 But then as I dial back, when I'm throwing a put, my hand opens up,

31:14 so I'm producing less friction out of my hand,

31:17 moderating the spin rate of the disk.

31:19 [D] So you're adjusting the spin rate just with how you hold the disk.

31:24 [E] Exactly.

31:24 It's not really a conscious thing, though.

31:26 [D] Okay.

31:27 [J] Something that you will get to see if you If

31:30 you ever watch slow-mo flight is a lot of times people,

31:33 when they throw their shots,

31:35 especially forehand, something you see a lot on forehand,

31:37 is that when the disk comes out of the grip,

31:38 the disk is what we call fluttering.

31:41 And the more spin a person throws the disk

31:44 with, the faster the disk will stabilize in its flight,

31:47 and then the disk can do what it's intent is to do.

31:51 It'll fly more like what Simon is saying,

31:53 the intent of the stability of the disk will be more true.

31:56 Now that we understand how the professionals think about the disk,

32:00 it's really cool to see it in action in actual competition.

32:04 The opening ceremony for Worlds was fascinating.

32:07 288 athletes from 47 countries.

32:10 This is a huge thing.

32:11 It's hard to believe that this is not an Olympic sport yet.

32:14 I got to believe one day it will be.

32:16 Temper of Finland really put on a show for this opening ceremony.

32:19 The next day, they got started with competition,

32:21 and it was really cool just to feel

32:24 the energy of the spectators and the athletes themselves.

32:27 It was awesome.

32:28 Representing Germany Simon Nizard.

32:33 After talking to the athletes,

32:35 I had a newfound appreciation for what I was seeing.

32:39 Knowing that Simon had to throw it right in between these trees,

32:42 I had a good feel for what he was thinking and how he was going to throw.

32:45 Watch this one from Eagle.

32:51 This is incredible.

32:52 He's doing the X step, right?

32:54 And then he's reaching back and he's transferring

32:56 all the force from the ground to the disk.

32:59 It almost sounds It feels painful when he releases.

33:03 If you zoom in on the waveform,

33:05 you can hear there are two distinct things happening.

33:08 I have no idea what it is, but he is imparting a tremendous amount

33:12 of translation power and spin to that disk.

33:16 Listen to that.

33:18 I started following the top card for the women.

33:21 These are the best players in the world, and I got to see them in real-time

33:25 make a decision using all this information we've learned.

33:28 It was fascinating.

33:29 So So I got my hands on this yellow media vest,

33:33 which allowed me to go just inside the rope and get closer

33:36 to the action so I could see exactly what was going on.

33:39 And I spoke to an official who was explaining to me

33:42 that they were about to make a very complex decision on hole 11.

33:45 So when they throw here, they're all going between these trees.

33:50 Yeah, usually the sweet spot is here,

33:53 that's tree or good players throw in this basket.

33:57 That's the sweet spot.

33:59 The They're just going to either shoot it straight through the trees here.

34:02 And if you remember, Simon said that's the hardest throw in disk golf.

34:05 This is what that would look like from the backside,

34:08 or they can curve it around these trees here and try to avoid that water hazard.

34:12 And again, this is what that looks like from the backside.

34:15 So they had to decide if they were going to use hyzer, over stable, understable.

34:19 What were they going to do?

34:20 And it's just a fascinating thing to watch it play out.

34:23 Okay, so the first person looks like they use some type

34:26 of hyzer throw to go around the trees and over the water.

34:30 And that, to me, feels pretty risky because if you hit a tree,

34:33 you're right in the drink there.

34:38 The second player was Silva, one of the newest players on MVP's team.

34:45 She's from Finland.

34:46 She went straight.

34:47 It wasn't arcing very much.

34:49 It was a straight shot.

34:50 I don't really know how she did that.

34:56 She goes low.

35:04 The third player decided to use the hyzer technique again,

35:07 and the power was there, but unfortunately, the curve cut a little too soon.

35:15 The last player is Cadence Berg.

35:22 She's from Alabama, so I was really excited to watch her.

35:25 She chose the left path.

35:27 She came this way with it.

35:35 It's stressful.

35:36 It's very stressful.

35:39 It was so fun running around the course

35:41 and just watching these impressive athletes that were just so

35:44 smart in terms of their understanding of what

35:47 the disk would do with their physical intelligence about it.

35:50 It was amazing.

35:51 I was also blown away by how international the event was.

35:55 Not only were these athletes from all over the world,

35:58 the fans were from all over the world.

36:00 They had come to Finland,

36:02 and they were rooting for different players from different countries.

36:05 It was amazing..

36:09 Frisbee golf.

36:12 Your family's from Mexico, you're from America,

36:14 and you follow a finish disk golfer.

36:16 Why?

36:17 She's one of the best.

36:18 She's one of the best.

36:19 She crushes.

36:19 You see her go long on this one-off the tee?

36:21 Yeah.

36:22 It was amazing.

36:23 She's been going aggressive this whole round.

36:25 It's been not paying off for her because she's got this incredible shoes,

36:28 but she's amazing to watch.

36:29 She's a reining champion.

36:30 Here we are on hole 16 in Tampara, again.

36:33 We're watching the ladies try to negotiate over to that hay bale Island.

36:38 I'm watching with my new Mexican friends,

36:40 and it's just really cool to see what these players do in this situation.

36:46 She's trying to make it past this island.

36:47 This was the first day, so there weren't as many people as the final days,

37:00 but there were already thousands of people on the course,

37:03 and some of them had paid extra money

37:06 to sit closer to the tee box when they throw.

37:08 It was a very interesting system, and I got to move around with the crowds

37:13 and understand how the whole thing worked.

37:15 It was fascinating.

37:16 The crowd wranglers look like a very stressful job.

37:19 We are going the same way as the players, so let's give them some room.

37:23 Also the media.

37:25 Be careful.

37:26 Those trees might be slippery, so be careful.

37:30 Wait, wait, wait, wait, wait, wait, wait, wait, wait.

37:32 This is so funny.

37:33 People are pushing and stuff.

37:40 What's your name?

37:42 Atin.

37:42 Atin.

37:43 Do you have to be mean?

37:46 I don't say that I want to be mean, but I have to.

37:50 You're going to have to because the crowd's excited.

37:53 The Finns took this event incredibly seriously.

37:56 It was on the National Streaming Service.

37:58 The whole country was talking about it.

38:00 And so that morning, we're eating pastries at a bakery.

38:03 We're just watching the whole event.

38:05 It's really, really interesting.

38:06 So when we got there,

38:08 You Ho and I were coordinating where we should be by watching that stream.

38:12 And then I realized there's a camera crew making this happen.

38:16 I bet they're interesting.

38:18 So the camera guys are running all over the course trying to get there.

38:21 I'm going to watch you.

38:23 Yeah.

38:23 What's your name?

38:25 Maxence.

38:26 Maxence?

38:26 Yeah.

38:27 I'm Destin.

38:27 Nice to meet you.

38:28 Are Are you broadcasting?

38:30 Yeah.

38:31 Really?

38:31 Yeah.

38:33 Okay.

38:42 Let's go behind the basket.

38:47 Behind the basket?

38:52 I don't know what to do.

39:00 You have a computer on your back.

39:02 A live view.

39:03 It's not a computer, it's a live view.

39:04 A live view?

39:05 A live view, yeah.

39:07 And so that's transmitting back to the center hub?

39:09 Exactly.

39:10 So obviously, I had to go find the hub.

39:13 Are you a disk golf network?

39:14 Yeah.

39:15 I'm Destin.

39:16 I'm Media Operations Manager.

39:18 And your name is?

39:19 I'm Blaine.

39:20 Blaine.

39:21 This is what they're wearing on their back?

39:23 [B] Yes, exactly.

39:24 And then we have DTAP batteries to make it charge.

39:26 But then inside here, it's all the brains.

39:30 [D] Those are cell phone SIM cards?

39:32 [B] Just a bunch of SIM cards in there.

39:33 And then, yeah, cell phone towers.

39:35 So we don't actually see what's switching live.

39:37 In my ear right now is we have a control call,

39:40 and he's directing the call to all of our camera guys right now.

39:44 [D] And they know their number.

39:46 [B] they know that each one has...

39:48 Each camera has their own number.

39:50 So number three is on Simon right now.

39:52 Correct.

39:54 Are you able to show me what number five is doing?

39:59 Because I saw him earlier.

40:00 Number five.

40:03 What about camera one?

40:06 He was with...

40:08 So one, two, three is with the lead card.

40:10 Yeah.

40:11 And then four and five are both chase card.

40:14 Seven is actually the drone.

40:15 Six and eight are with just whoever shooting high right now.

40:18 That's incredible.

40:19 And we can split those guys up if we wanted to.

40:20 And you have people in America

40:22 and other countries switching this at their house?

40:25 Yeah.

40:26 In the States?

40:27 Yeah.

40:27 It's all in the cloud.

40:28 Wow.

40:29 And staying up as late as possible.

40:30 It's incredibly legit, but incredibly lean.

40:34 [S] Yeah, we're breaking a lot of broadcast rules.

40:38 [D] In what way?

40:40 [S] The fact that we're using completely

40:42 just bonded cellular transmission is a lot

40:47 of people view it as very risky because when you think about it,

40:52 when you look at a main golf broadcast, they're running fiber or they're doing

40:58 point-to-point RF for cameras transmission stuff.

41:00 It's all gone to a truck on site.

41:02 And then from there, they can broadcast it out to the world.

41:06 For us, we're relying on cell phone networks that we really have no control of.

41:12 [D] So you're like, We're doing it live.

41:16 I thought the TV thing was worth it.

41:17 I know that was a side tangent there,

41:19 but it's time for us to move to the next step

41:21 in our understanding of how to throw disk golf disk, right?

41:25 It's time to go talk to some engineering nerds.

41:27 Now, I wanted to stay for the rest of the event,

41:30 but Youhou had some friends that captured

41:32 some footage of how amazing that became.

41:35 But we're going to move on to the tech geeks, okay?

41:38 So the pros, they had a physical understanding of how the disk works,

41:42 but they couldn't really articulate that from a numerical perspective.

41:46 It's time to learn the numbers.

41:48 So there's some Americans that made this thing,

41:51 and they met me in Finland at this place down the road.

41:55 I just wanted to document that Youhou drives like a madman.

42:00 [Y] I'm just a normal fan.

42:03 Now, Youhoe drove me there, and I, of course,

42:05 like to pretend that all [D] Finnish people drive to death metal all the time.

42:10 We went to a place called Disk King.

42:12 That's what it translates to.

42:13 This is a second-hand disk golf disk store, and they do fulfillment.

42:18 They mail these things all over the world,

42:21 and they've got this really big business.

42:23 But as a part of their business,

42:24 they have a simulator in the back room, and that simulator is made by Americans.

42:28 These Americans that made this simulator technology

42:31 went over to Finland to see worlds,

42:33 but they agreed to meet me at the simulator so we can

42:36 talk about the numbers associated with the physics of throwing a disk.

42:40 Hey, I'm Destin.

42:41 Michael.

42:41 Michael.

42:41 Great to meet you.

42:42 We e-mailed.

42:43 John?

42:43 Yeah.

42:44 Okay, cool.

42:44 I want to know about your technology because I went and learned

42:47 about how disk golf disks are released and stuff like that.

42:51 I learned words like hyzer, Anhyzer.

42:53 I think that's right.

42:55 No, hyzer.

42:56 Gosh.

42:56 [M] You did it the first time.

42:57 Yeah.

42:58 Hyzer and then Anhyzer.

43:00 Okay, cool.

43:01 I learned those terms.

43:03 But there's other things that I'm interested in, like release angle,

43:06 like angle of attack up or down, and spin rate.

43:10 I think those are interesting.

43:12 And is that the thing on the disk there?

43:14 [M] Yeah.

43:14 So This is what's going to measure all that for us.

43:16 This is a tech disk.

43:17 It's a normal golf disk, but with a suite of sensors installed on board.

43:22 This is what we build in Kansas City.

43:24 This is what measures your throw and all the metrics you're talking about.

43:27 [D] Is this an IMU, an inertional

43:29 measurement device or inertional measurement unit?

43:31 [M] Yeah, we have a lot of accelerometers and gyroscopes on here,

43:33 and that raw data gets sent up to the cloud

43:36 to get processed into a motion that we can understand.

43:38 [J] This is the main IMU thing that you're asking about.

43:41 [D] What?

43:42 It's like...

43:43 Okay.

43:44 Can you Oh, wow.

43:46 Okay, so what on Earth?

43:50 Okay, that's cool.

43:51 That's very cool.

43:52 [J] It's always tracking the orientation of the disk.

43:57 Then there's a suite of accelerometers that when you throw it, can go up.

44:02 So some of the pros can throw over 200 Gs at that hit point.

44:06 [D] We geeked out over the physics together,

44:08 and turns out we had read some of the same research.

44:10 And the seminal paper on this, we talked about on the phone, right?

44:14 And that's Potz, right?

44:16 Potts, yeah.

44:16 Dr.

44:17 Potts in England.

44:18 [M] Yeah, some of the best experimental data that's been done out there.

44:21 [D] So they showed me how it worked, and it felt like a game.

44:24 There's this disk, and it has instrumentation on it.

44:26 And when you throw it, it interacts with the virtual the world.

44:30 But what's really cool about it is it gives

44:32 you the data of the throw you just made, like the actual numbers.

44:38 Oh, wait, we're at a different level now.

44:40 Okay, hold on.

44:41 So you can get speed.

44:43 [M] It's on kilometers an hour.

44:45 I can't throw 77 miles an hour.

44:47 [D] That's good.

44:49 Does it know that you did a backhand hyzer?

44:51 It knew that.

44:52 [J] It does.

44:52 We told the app that we're throwing right-handed.

44:55 So we're going to label it as a backhand hyzer.

44:57 [D] So it knows from the data, backhand hyzer, it It knows the speed,

45:00 it knows the spin, the wobble, the hyzer, the nose angle, and the launch angle.

45:07 Oh.

45:07 They let me try it out.

45:09 And just playing this for one hole led to a revelation

45:13 for me for understanding why a disk does what it does.

45:18 So I'm about to get to play hole 16, you said?

45:21 [J] Hole 16?

45:22 [D] Okay.

45:23 [J] The beast.

45:23 [D] Yeah, the beast.

45:24 This is the beast in Nokia, hole 16.

45:28 And this is the one where you have to hit the island,

45:31 and that first throw really matters.

45:33 The cool thing about playing this particular hole, virtually, hole 16,

45:37 is that I actually got to film how the professionals approach the hole.

45:42 Remember, they have to go over the out-of-bounds area and land in the island?

45:46 Well, here we have four different people throwing from a fixed camera view,

45:51 and you can see that each player takes

45:53 a little different approach to get to the basket.

45:56 Fascinating.

45:57 Am I at the tee box right now?

45:58 You are on the tee It works.

46:00 Okay, so I'm just trying to get out onto the fairway there.

46:04 I'm just going to do that.

46:05 So I'm not going to throw crazy.

46:08 I went left.

46:11 [M] It's probably going to go left.

46:12 [D] It's probably going to go left?

46:13 [M] Yeah.

46:17 [D] Oh, dude, I'm really bad at this.

46:20 They make it- That's fine.

46:22 I think we're having a good time.

46:24 They make it look so easy.

46:25 Okay, so now I'm here.

46:27 So I can rotate.

46:28 Yeah, rotate me.

46:29 No, there's [J] We're going to point you this way.

46:31 Let's play the fairway.

46:32 [D] Let's play the fairway.

46:33 Okay.

46:35 I've got a green dot here, so I'm ready?

46:39 [J] You're ready.

46:39 Yep.

46:40 [D] Okay.

46:40 Throwing.

46:43 All right.

46:44 Again, left.

46:45 My launch nose angle was 11, which is way too much.

46:53 I learned from those guys, if you have a high launch angle,

46:56 that it's like putting the brakes on.

46:59 I You threw too high.

47:01 Is that what happened?

47:02 [J] You threw too high, and your nose was even higher.

47:06 You threw it up in the air, and you put the brakes on.

47:10 [D] Really?

47:11 So my launch angle was 4.

47:14 7, and my nose was 11.

47:16 3.

47:17 Those are two different things.

47:19 [J] And so nose is traditionally called angle of attack.

47:23 [D] Yes.

47:23 [J] And so nose is relative to launch.

47:25 So you can throw up and still throw the zero nose.

47:29 [D] So I threw up at 4.

47:31 7 degrees.

47:32 [J] Traveling this way?

47:33 [D] But I threw it like that.

47:34 [J] Yes.

47:35 You can imagine when it's traveling this way.

47:36 [D] I just made it a parachute.

47:40 Okay, this is a cool data.

47:41 [J] So what we say is launch is relative to the ground.

47:45 [D] Yes.

47:45 [J] Relative to the horizon, and nose is relative to launch.

47:48 Now, let's do the opposite of that.

47:50 We'll throw up in the air with a positive

47:52 launch and get that nose down so you can travel.

47:54 [D] Okay, let's do it.

48:01 [J] If we replay that, it should slow down right there.

48:05 You're going to see a positive launch angle.

48:09 [D] The nose was down.

48:11 Frame that.

48:14 The nose, yeah.

48:15 [J] Yeah.

48:16 What I like to do is draw a line for that launch angle.

48:18 Starts here, launch angle goes here,

48:20 or the launch trajectory, we'll say, is here.

48:23 [D] Yeah.

48:24 [J] You see that disk is not lined up with that.

48:26 It's actually below it.

48:27 [D] Yeah.

48:29 Yeah.

48:30 [J] That nose, trajectory is here,

48:31 but the disk is oriented this way, so it's nose down.

48:35 [D] What you're saying is the aerodynamics

48:38 of disk off disk is a complicated thing.

48:40 [J] It's a complicated thing.

48:42 [M] But in the best way possible.

48:44 [D] Why?

48:45 [M] Because it's so much fun.

48:46 [D] I see.

48:47 [J] It's so interesting.

48:48 Yeah, you can go forever and not feel like you know everything.

48:50 But we did try to make it as simple as possible,

48:53 boiling all that down to six metrics so you can work on getting better yourself,

48:56 even if you don't fully understand all the aerodynamics of it.

48:59 [D] What are the six metrics?

49:00 [J] The six metrics are speed, spin, wobble,

49:03 and then the angles, hyzer angle, launch angle, and nose angle.

49:07 [D] Okay.

49:08 So it's not...

49:10 Yeah.

49:11 Speed, spin, wobble, hyzer angle, launch angle, nose angle.

49:17 [J] Right.

49:17 [D] Is that it?

49:18 [J] Yeah, that's it.

49:19 [D] That's awesome.

49:20 Okay, so I need to go talk to Dr.

49:22 Potts.

49:22 [J] Awesome.

49:23 Okay.

49:24 You remember at the beginning of this video,

49:25 I told you we were going to meet a professor, Dr.

49:27 Johnny Potts.

49:28 Well, it's time for us to get an airplane and fly from Helsinki,

49:32 Finland, to Manchester, England, to Sheffield, Holland University.

49:35 This is Dr.

49:36 Potts' PhD dissertation or thesis,

49:37 I think they call it in the UK, Disk-wing aerodynamics.

49:43 This thing is literally the book on disk flight,

49:46 or at least the best book that I have found.

49:49 An interesting thing about Dr.

49:51 Potts' thesis here is he doesn't talk a lot about a spinning disk.

49:55 He talks a lot about a disk flying without spin.

50:00 Dr.

50:00 Potts and I have had a lot of phone conversations prior

50:03 to the meeting outside the bus stop you're about to see here.

50:05 And we've discussed the various physics having to do with disk flight.

50:09 I'm very excited to finally meet

50:11 this academic legend of flying disk aerodynamics.

50:15 Good to meet you.

50:16 Destin.

50:16 The first thing we did is Dr.

50:19 Potts walked me into the amazing aerospace research

50:22 facilities they have there at Sheffield Holland University.

50:24 We walked in and we got to see some of the wind

50:26 tunnels and some of the incredible lab space they have there.

50:29 It's awesome.

50:30 We're going to use these things to try

50:32 to figure out some specific physics of disk golf flight.

50:36 In fact, Chad from MVP Disks,

50:38 Chad made some aluminum disks that we shipped over, and Dr.

50:43 Potts and I are going to rig this thing up,

50:45 even with a spinning rig for a future video that we're hoping to work on.

50:48 But for now, we're just going to pick Dr.

50:51 Potts' brain and try to understand a little bit more about disk golf flight.

50:56 Early in flight, it's flying really fast.

50:58 High spin rate, high speed.

51:00 But at the end of the flight, when it starts dying, it starts doing this.

51:04 Yeah.

51:05 [P] That's because drag, the resistance to motion.

51:10 So as the disk flies through the air, you have a drag force,

51:13 which is slowing it down over the entire flight.

51:17 As they release, as you quite rightly say, it's very fast in the spin rate.

51:22 Spin rate probably doesn't change too much, actually, from the start to the end.

51:26 But the actual resistance to motion as the disk flies forward slows it down,

51:31 and then the vertical velocity increases towards the end,

51:34 which is why you see it.

51:37 Then as the vertical velocity increases, the disk slows down,

51:40 and then there's not as much force in terms of lift to support its weight.

51:44 Then it starts to come back to the ground.

51:47 As it does that, the angle of attack

51:49 then increases towards the end of the flight.

51:53 That's where you see the almost a hovering effect as it

51:56 comes to the ground sometimes for a disk like this.

52:00 [D] Yeah, exactly.

52:01 One thing that they said happens in flight a lot

52:04 is a lot of times when you throw a disk,

52:07 if you're the basket and I'm throwing towards you,

52:09 and just assume this is spinning, as it's coming at you,

52:13 it'll come over this way, and then towards the end, it'll die.

52:17 Yeah, that's right.

52:17 The turn and the fade.

52:19 [P] Yeah, and we can look at some graphs

52:21 to talk about that later of why that happens.

52:24 [D] You know why it happens.

52:25 [P] Oh, yeah.

52:25 Because you get a trim condition, what's called in aerospace.

52:29 As the disk is launched,

52:31 it comes from a low angle of attack to a high angle of attack.

52:36 We pass through this trim condition, which is zero pitching moment.

52:40 Initially, we have negative pitching moment,

52:44 which means the disk from a right-hand,

52:46 back hand throw, it comes up like this and then starts to drift right.

52:50 Then as it goes through the trim condition,

52:52 it stays in that orientation, it won't move.

52:55 Then as it goes to a positive pitching moment,

52:57 then it starts to then roll back and get this S-shaped flight path.

53:03 And that's why they were talking about this, and that's why it happens.

53:07 And I can show you a graph.

53:08 It's just the basic pitching moment graph that you've

53:10 probably seen in the papers that we've published.

53:15 Yeah, but that's why.

53:16 Dr.

53:17 Potts, clearly extremely smart.

53:19 So the purpose of this video, we're trying to understand why does a disk curve.

53:23 So the chart that Dr.

53:25 Potts is showing me here on the screen is this one right here, Figure 5.

53:29 4 0.

53:29 13.

53:31 It's like a subgraph on his PhD here.

53:34 This curve is the key to understanding why disks curve when they fly.

53:40 It's fascinating.

53:41 But in order to explain this curve,

53:43 pitching moment coefficient as a function of angle of attack,

53:46 we're just going to experience it.

53:48 So the thing that we did first is Dr.

53:50 Potts took me to a wind tunnel where we had a half scale model set up,

53:54 and we could pitch this disk at different angles of attack.

53:58 And we had a little smoke streamer that we put right on the front of this thing.

54:01 And as we vary the angle of attack,

54:04 you could see how the airflow separates over the backside of the disk.

54:08 There we go.

54:09 Slow, slowly, slowly.

54:11 [P] You have to follow the leading edge.

54:18 [D] That was cool.

54:21 That was very cool.

54:24 Can you do that one?

54:25 [P] Yeah.

54:25 [D] One more time?

54:27 [P] Zero, 10, 20, 30, 40, 50, 60.

54:39 So this little wind tunnel demonstration, it wasn't an experiment,

54:42 it was a demonstration, can tell us a lot of things, okay?

54:45 So as you first throw the disk, right?

54:47 Really, really fast.

54:49 So it's going to fly super level and straight, right?

54:52 But towards the end of the flight where it starts running out of gas,

54:55 it's going to start falling to Earth like this, right?

54:58 And if you think about it, that means the angle of attack of the air

55:01 is going to change to something down here.

55:03 What's the last foot of the throw, right?

55:07 It falls right to Earth and it goes straight down, right?

55:11 So the air is actually coming from here.

55:12 So we have this whole sweep of aerodynamic possibilities.

55:16 But what's interesting about that is if you look

55:18 at the flow over the back of the disk,

55:21 at the beginning, the flow is attached to the disk.

55:24 But towards the end, you end up getting this really weird bubble off

55:27 the back of the disk where you get flow separation.

55:30 So we have a different pressure situation along the back of the disk,

55:35 and it varies throughout the flight of the disk.

55:39 That's important.

55:40 So if I'm launching this direction, going that way,

55:44 the center of mass is right here in the center, right?

55:47 [P] Yeah, correct.

55:47 [D] Where is the center of pressure on a disk?

55:49 [P] The center of pressure can move.

55:51 It moves through the center, essentially.

55:53 It moves from across that center location.

55:57 That's why it pitches nose and then nose down.

56:00 [D] Does the center of pressure start

56:02 in the back because you're going high speed?

56:05 Then as it slows down, does the center of pressure move forward?

56:09 [P] It starts slightly further back, you're right,

56:11 as you get a slightly negative angle of attack,

56:15 and then it moves further forward.

56:18 So you get a pitching moment,

56:20 which actually makes it roll right from a right-hand back and throw.

56:24 And then as the pitching moment moves forward, then it comes It's all right.

56:30 Does that have to do with gyroscopic procession?

56:33 [P] That's right.

56:34 Yeah.

56:34 Okay.

56:35 I said two fancy pants things there, right?

56:38 The first one was center of pressure, and the second was gyroscopic procession.

56:43 Potts knows what I'm talking about.

56:45 I kinda know what I'm talking about.

56:47 So I'm going to just briefly break that down right now.

56:49 So let's say we've got the disk, right?

56:51 I've got a wet erase marker here,

56:53 and we've got the center of gravity right here on the disk.

56:57 Okay, that's the center of the disk.

56:59 It's pretty easy circles.

57:00 You always know it's right in the middle.

57:02 Where is the center of pressure?

57:04 What is the center of pressure?

57:05 Well, if you ask an aerodynamicist,

57:07 they're going to laugh at you because it's one

57:09 of the hardest things to figure out from my perspective.

57:13 I'm going to grab something off the shelf.

57:14 I've I've never used in a video, but I think it's really cool.

57:17 If you were to ask an aerodynamicist,

57:19 please calculate the center of pressure on this T-38 aircraft,

57:23 they're going to laugh at you because it's a hard thing to do,

57:27 because you have to take into account things like body drag,

57:30 like literally the friction of the air on the skin of the aircraft.

57:35 How much surface area do you have at different points along the aircraft?

57:39 In fact, this particular aircraft, it's made so that it's a...

57:44 I forget the name of the theory.

57:46 The cross-sectional area of this aircraft, they try to keep it the same.

57:49 You'll notice right here, the fuselage goes in a little bit.

57:52 It's got hips when the wings go out.

57:54 There's a whole lot that goes into calculating the center of pressure.

57:58 And the reason you would want to do that is It's because this is a tank-fired K.

58:02 E.

58:02 Rod.

58:02 This is what's fired out of a main battle tank.

58:04 It's awesome.

58:06 I think it's a Russian one,

58:07 but the way it works is if I try to balance this thing,

58:10 I can say, Okay, the center of gravity is about right there.

58:14 These fins What are the purpose of the fins?

58:17 It's to pull the center of pressure behind the center of gravity.

58:21 Because as I fire this thing at really, really fast,

58:24 I want to have what's called a riding moment that aligns it.

58:29 So if you think about it,

58:30 if I fly through the air like this, there's going to be more dragged down here,

58:34 and it's going to pull it around the center of mass, right?

58:38 Well, that's interesting because our center

58:40 of pressure is behind the center of gravity,

58:42 which means this is aerodynamically stable.

58:45 What would happen if I tried to fire it like this?

58:47 Well, it would automatically ride itself because there's a riding moment.

58:50 It's a very interesting thing.

58:52 That's why arrows have fletchings or feathers.

58:54 I always had a hard time understanding what center pressure actually was.

58:56 But look at this.

58:57 If I were to take, in this case, a wing,

58:59 and I were to average out the pressures all around that wing,

59:03 they would equate to one force going through one spot.

59:07 In that little spot right there, that is the center of pressure.

59:11 Okay, let's go back to the disk.

59:12 Okay, so we've got our center of gravity of the disk here, right?

59:15 Okay.

59:16 So as we fly this thing in the wind tunnel,

59:19 like we said earlier, we start in all that wind, the air is going over the top,

59:23 and we have an attached flow to the back of this thing.

59:27 So if you think about it, if we think about it like the aircraft,

59:30 and we have all the body drag and the fins

59:32 and all this, that means everything comes into play.

59:36 This little groove on the bottom side of the disk, that comes into play.

59:39 That affects drag.

59:41 This little nose, the leading edge, that affects drag.

59:44 The surface finish of the disk.

59:46 All these things affect where the center of pressure is.

59:50 But if I'm flying towards you, that's my cross-sectional area.

59:53 What happens when I tilt it up?

59:55 It changes.

59:56 So suddenly my center of pressure changes, right?

1:00:00 And on top of that, we've got that flow separation off the top.

1:00:03 So what Potz just said is he said there's like

1:00:06 a line from the front to the back through this disk, right?

1:00:10 And he said that our center of pressure starts off somewhere in the back.

1:00:15 And that makes sense because we're flying level, right?

1:00:18 But as we start to tilt up, we get that bubble right here.

1:00:21 We have drag stuff going on on the front, even.

1:00:24 And so our center of pressure is going to move forward, okay?

1:00:29 But you got to remember, this thing is spinning.

1:00:32 So we've got a center of pressure that's moving forward,

1:00:35 and that's creating lift in different places, and we're spinning.

1:00:39 So that's going to factor into a gyroscopic procession.

1:00:43 I've always used the term center of pressure,

1:00:45 but there's some other terms there, center of lift or whatever.

1:00:48 But anyway, the point is the center of pressure is moving,

1:00:52 and so now it's time to go to the garage and look at gyroscopic procession,

1:00:56 which is where the big setup is to understand that.

1:00:59 Okay, Let's go to the garage where I have this really awesome setup.

1:01:04 In fact, I did this on the last episode of Smarter Every Day, episode 312,

1:01:08 we talked about gyroscopic procession because I wanted this thing

1:01:10 to be its own video because of how cool this is.

1:01:14 I have a big model of a disk here, right?

1:01:17 It's suspended from these wires, from the ceiling.

1:01:20 I've got these cameras set up that I've already turned on.

1:01:23 So this camera is looking 90 degrees to the flight line.

1:01:27 This is looking along the flight line.

1:01:29 You'll notice I've got the flight line illustrated

1:01:31 here by a blue tape arrow on the floor.

1:01:35 Imagine that we are throwing this disk in that direction.

1:01:40 We're going to do a right-hand, back-hand throw.

1:01:43 And the purpose of this is just to demonstrate gyroscopic procession.

1:01:47 And in the last video, I did this really interesting model,

1:01:51 at least interesting to me, of these pool balls on a stick.

1:01:55 And once we started rotating this thing and we hit it with a pool ball,

1:01:59 you see the gyroscopic procession take place, or at least something like it.

1:02:04 So gyroscopic procession basically shows you that if you

1:02:08 have a spinning object and you push on it,

1:02:12 the displacement happens 90 degrees after the place where you pushed on it.

1:02:16 And I'm going to show you that now.

1:02:19 So let's just get a baseline here for thinking about it.

1:02:22 And I highly recommend looking at that other

1:02:24 video if you want to understand this better.

1:02:26 So we have this disk, and I'm just going to push down right here.

1:02:30 And you'll look at it from that camera right there.

1:02:32 And you'll notice that when I push down,

1:02:35 because I'm imparting a torque about the center of mass,

1:02:38 it ends up tilting just like you would expect, right?

1:02:42 I'm pushing straight down and I get a torque over there pitching that thing up.

1:02:48 What happens when we spin it up?

1:02:50 Okay.

1:02:51 So again, looking at it from this side, I'm pushing down here.

1:02:54 It tilts up like that.

1:02:55 Okay, so now let's spin this thing up.

1:02:57 What did I do with my drill?

1:02:58 Here it is.

1:02:59 So now I'm We're going to impart a spin to the bottom

1:03:03 of this, and then we're going to push down in the same place,

1:03:07 and we're going to see what happens.

1:03:08 Let's get this thing going.

1:03:09 This is a little paint stirrer in a 3D printed connector that I made.

1:03:15 Let's spin this up now.

1:03:22 Okay, that might be the fastest I've ever gotten.

1:03:25 This is pretty great.

1:03:26 Okay, so now I'm going to do the same thing,

1:03:28 only I'm I'm going to push down with air.

1:03:31 And from this camera, remember, it tilted up.

1:03:34 Look what it does this time.

1:03:35 It's going to tilt 90 degrees after.

1:03:41 You see that?

1:03:43 Oh, I need some I need some oil on my bearing.

1:03:47 Does that help?

1:03:48 Come on.

1:03:51 That doesn't help.

1:03:51 All right.

1:03:52 Okay, so what happened there is when I pushed down on this edge with the air,

1:03:57 it actually pushed down about 90 degrees after, which is really weird.

1:04:02 In the previous episode,

1:04:04 we showed that if you put a force into a rotating mass system,

1:04:09 then that force turns into what seems like a displacement

1:04:13 90 degrees after the place where you input the force.

1:04:17 We showed that with pool balls and the sticks,

1:04:19 and it was really interesting, and that works for my brain.

1:04:22 But this same thing works with a rotating disk.

1:04:24 I highly recommend checking out the earlier

1:04:27 episode to understand what's going on.

1:04:29 But I want to I'm going to talk about

1:04:31 what that does for us in terms of disk golf.

1:04:33 I'm going to stop this thing so we can just talk about it here.

1:04:37 I'm going to put you up right here, okay?

1:04:41 We'll have a little conversation.

1:04:44 Man, it's pretty wobbly, isn't it?

1:04:46 All right, so we'll slow this down.

1:04:50 Okay, so we're flying in that direction now.

1:04:52 So Potts was talking about the fact that we

1:04:56 have this longitudinal line running from tip to the tail,

1:05:01 so to speak, of the disk.

1:05:03 And so I'm going to actually draw a line on the disk,

1:05:07 and we're going to move things along that line and talk about it.

1:05:11 Okay, so if we think about the disk flying

1:05:13 and we think about what we saw in that wind tunnel,

1:05:17 we had air providing lift on the disk, right?

1:05:20 So it's like a weird airfoil.

1:05:23 And so it's going to be lifting.

1:05:24 It's not going to be right in the middle.

1:05:26 It's going to be somewhere back here.

1:05:28 Dr.

1:05:28 Potts said it's going to start a little bit further back.

1:05:31 And if we think about this thing, lift is lift.

1:05:34 It's actually pulling up on the disk.

1:05:37 And so that's what lift would look like on a stationary disk.

1:05:41 But this is not a stationary disk.

1:05:42 This is a rotating disk.

1:05:45 Therefore, gyroscopic procession is a thing.

1:05:48 So it's almost like that lift vector creates this displacement

1:05:52 vector that's actually over there to the side, like that.

1:05:56 So when we first start off,

1:05:58 that lift is going to And you start to try to displace the thing like this.

1:06:03 Isn't that interesting?

1:06:04 Now, Dr.

1:06:04 Potts said that that center of lift or the aerodynamic

1:06:07 center is going to move forward throughout the flight.

1:06:11 Now, think about this.

1:06:12 If that's true, then that means that displacement

1:06:14 vector is going to move as well.

1:06:16 See, this is basically what we're referring to as the pitching moment.

1:06:20 A moment is another fancy way of saying torque.

1:06:23 And so the distance from the center and the force,

1:06:26 those two things combine to give you the pitching moment.

1:06:29 So because lift force is going from the back

1:06:31 of the disk to the front of the disk,

1:06:34 it's almost like that displacement effort is going from the left

1:06:38 of the disk to the right of the disk, which is fascinating.

1:06:42 Let's look at that graph that Dr.

1:06:44 Potts had in his dissertation, and let's look at the wind tunnel experiment,

1:06:47 and let's just look at what's happening.

1:06:50 As the angle of attack changes,

1:06:52 that pitching moment moves with the angle of attack.

1:06:55 It goes from negative to the neutral

1:06:57 point or the trim condition back to positive.

1:07:00 Let's go talk to Dr.

1:07:01 Potts and try to understand what that means.

1:07:04 Okay, we want to see the whole flight of a disk,

1:07:06 what's happening along the whole way.

1:07:08 So we're going to throw a right-hand, back hand.

1:07:11 How does it work?

1:07:12 Don't worry about the cameras over there.

1:07:15 [P] I'm just going to draw the flight path of a typical flight initially.

1:07:20 It goes reasonably straight and we get that turnover, and then it drifts right,

1:07:25 and then we get that hard turnover back the other way.

1:07:32 I'm going to draw the pitching moment which drives it,

1:07:37 which is what we were looking at before, which is something like that.

1:07:41 This is the pitching moment coefficient against angle of attack.

1:07:47 Then we're going to relate what happens in the flight,

1:07:51 primarily because this roll is driven by the pitching moment,

1:07:55 which is this curve.

1:07:58 [D] The pitching moment is a function I've got lift

1:08:02 that's moving along this axis from here to here, right?

1:08:06 But it's acting out of phase.

1:08:07 [P] Yeah, because of...

1:08:08 Just to recall that the roll is as a result of the pitching moment,

1:08:16 which is happening because of gyroscopic procession.

1:08:21 [D] Got it.

1:08:22 I'll do this.

1:08:24 We've got a disk here, and we have the center of gravity,

1:08:28 the center of mass, It's right here in the center.

1:08:31 Does that work?

1:08:32 [P] Yeah.

1:08:33 [D] Then could you maybe just talk about the center of buoyancy?

1:08:38 Not center of buoyancy, I'm thinking most Center of pressure.

1:08:41 [P] Center of pressure, yeah.

1:08:44 Related to in there.

1:08:46 If you've got the center, so the disk is traveling in this direction,

1:08:50 so the flow rate is here like this, so the flow coming that way.

1:08:54 We've got a direction of travel, a double,

1:08:57 triple, triple line, so that's direction of travel.

1:09:00 We were talking earlier about the center of pressure,

1:09:03 which starts, we call it, say, after or behind the center of mass,

1:09:10 which is then what drives the pitching moment.

1:09:14 You have lift which acts at the center of pressure.

1:09:17 [D] If I had a disk right here,

1:09:20 and so I'm basically pulling out of the board behind the center of mass.

1:09:27 I'm pulling at that location.

1:09:28 [P] Yeah, so the The lift force is acting perhaps out of the board.

1:09:33 Right.

1:09:34 [D] But because of gyroscopic procession, that doesn't happen.

1:09:37 It goes over here, right?

1:09:39 [P] Yeah, correct.

1:09:40 So it...

1:09:41 [D] Do you have another color?

1:09:43 [P] It lifts.

1:09:44 It It lifts the wing on the left-hand side.

1:09:50 The actual motion.

1:09:52 To talk in lift is incorrect, but the actual motion,

1:09:56 the motion as a result of the moment lift

1:10:00 force is actually at 90 degrees in the roll plane.

1:10:03 [D] All right, so let's just pretend it acts here.

1:10:07 Does that work?

1:10:07 [P] Yeah.

1:10:08 Okay.

1:10:09 That lift force translates around 90 degrees,

1:10:11 and then the motion as a result of that is to be this turnover,

1:10:15 which is happening here.

1:10:17 [D] Got it.

1:10:18 This is at the beginning of the flight.

1:10:20 Lift is acting behind the center of gravity.

1:10:24 [P] Dropping the nose.

1:10:25 [D] Dropping the nose, or trying to drop the nose.

1:10:27 [P] Trying to not drop the nose, yeah.

1:10:28 [D] But because the It's a gyroscopic perception,

1:10:30 it happens over here, and that's when it starts rolling anhyzer.

1:10:32 [P] Yeah.

1:10:33 [D] Okay.

1:10:33 [P] That's right.

1:10:34 [D] Okay.

1:10:36 [P] Then you get to maybe this point here.

1:10:42 Let's say in the middle of the flight,

1:10:45 On the pitching moment curve, you're actually at this point,

1:10:48 which I called trim condition, which is the correct name in aerospace,

1:10:51 which is basically where the lift now has moved.

1:10:56 It's now at the center.

1:11:00 I'm just going to draw it to the right,

1:11:02 so I don't… Yeah, just because… But it's at the central point.

1:11:07 Therefore, you don't have any moment at all.

1:11:10 The orientation of the disk at this point would just maintain whatever it was.

1:11:14 [D] I see.

1:11:15 [P] Yeah, at this point on the Pitching Moment Curve.

1:11:18 [D] I see.

1:11:19 [P] Then as you go into the positive Pitching Moment,

1:11:22 then it starts to drive the roll rate in the opposite sense.

1:11:25 You've got center of pressure here now.

1:11:27 Sorry, lifting center of pressure moves.

1:11:30 [D] All the way forward of the center of mass.

1:11:34 [P] Probably not too far, but just a certain distance.

1:11:37 I've probably drawn it too far.

1:11:39 Then that translates for a right-hand back-end throw,

1:11:41 of course, all this we're talking about,

1:11:43 it translates around 90 degrees to drive the rotation

1:11:47 in the opposite sense to the way it was before.

1:11:51 Then the curve, you think, into this phase.

1:11:54 [D] I see.

1:11:56 Yeah, as soon as it moves forward of this, that's That's when...

1:12:00 Yeah, I see.

1:12:01 I got you.

1:12:02 [P] Then it starts rolling left rather than right.

1:12:06 You got the initial turnover for the negative part of the curve here.

1:12:10 Then for the positive part of the curve, you're then rolling left.

1:12:14 It's that which gives you the classic disk flight trajectory, viewed from above.

1:12:21 [D] If I pick a disk out of the bag, can I expect it to do this every time?

1:12:27 [P] It depends on the speed of release,

1:12:31 and that would depend on whether you're an elite or an amateur player.

1:12:38 If we, for instance, suggest that that is a perfect S-curve for an elite player,

1:12:44 then they may be using a disk which is set up for them,

1:12:49 or they've chosen the specific disk to be able to turn over

1:12:52 just the right amount so that they get that distance that they're after.

1:12:57 Whereas a more amateur player, if I draw it blue next to it,

1:13:01 or maybe we should start from the same point.

1:13:04 It may not turn over as much, so it may go maybe here or something.

1:13:13 It may then turn hard left straight away

1:13:18 because it didn't quite reach this trim condition.

1:13:21 [D] Okay.

1:13:22 [P] Or maybe it goes into this beyond the trim condition much faster,

1:13:29 I think probably This is the way to talk about it.

1:13:33 Then they go over here.

1:13:35 Not only are they getting less distance compared to the elite player,

1:13:43 but they're also not managing to turn it over so that they're tracking

1:13:47 it more towards where they perhaps want to be for the same disk.

1:13:51 They would probably then, if they change their disk out to get more distance,

1:13:59 they probably to track more the elite

1:14:02 player trajectory in terms of the flight path,

1:14:05 then they could get a disk which turns over a little bit more.

1:14:09 And then let's say it tracks over here,

1:14:11 but they still can't quite get the distance

1:14:13 of an elite player because they don't have the speed.

1:14:16 But then they perhaps could get a bit more distance.

1:14:18 [D] Have you seen the...

1:14:20 [P] That makes sense?

1:14:22 [D] Yeah.

1:14:22 Have you seen the MVP flight feather concept?

1:14:26 Have you seen that?

1:14:27 So earlier when I was touring the MVP disk golf factory,

1:14:29 Brad and Chad had a poster in their office

1:14:32 that had something on it called the flight feather.

1:14:35 I now understand what they were talking about.

1:14:38 [B] So the left and right motion is a good example.

1:14:42 We have different lines that have different power levels.

1:14:44 If you're throwing it with lower power,

1:14:46 you're going to have it go straight and then hook to left a little bit.

1:14:49 As you increase that initial speed, you're going to see a turn phase.

1:14:52 When you throw at high speed with a disk that wants to turn under stable,

1:14:56 it'll drift to the right, right-hand, back hand.

1:14:59 It'll drift to the right, and as it slows down throughout its flight,

1:15:02 it'll begin to fade out left.

1:15:04 All right, here we are.

1:15:05 Hole 18.

1:15:06 Can we do it?

1:15:08 We can because now we understand the turn and the fade.

1:15:13 We understand that as it rotates.

1:15:15 We have gyroscopic procession,

1:15:17 and the center of lift moves along the longitudinal axis,

1:15:20 giving us that turn and fade.

1:15:22 Except that's not all.

1:15:25 I've learned in my whole life, if I think I understand something,

1:15:28 there's a bonus level right over there,

1:15:30 and we got to go check it out and think about it.

1:15:33 Let's go to the bonus hole.

1:15:35 Okay, this is extremely complex,

1:15:37 and I've been thinking about it for an inordinate amount of time.

1:15:40 I want to just say all the caveats

1:15:42 in the little outlier conditions because we simplified everything,

1:15:45 but I want to just get all of these ideas down.

1:15:49 So if you don't track this, what I'm about to say,

1:15:51 just hang with me because I think you can.

1:15:54 I think you can get this.

1:15:56 Why does a disk curve?

1:15:57 That's what we're trying to answer.

1:15:58 So Brad and Chad arrived arrived at the flight feather

1:16:01 by just observing what happens when people throw disks, right?

1:16:05 Dr.

1:16:05 Potts arrived at the flight feather using

1:16:07 physics and his understanding of this mental model.

1:16:10 One thing I think is interesting, though,

1:16:12 is there's so much more going on than what meets the eye,

1:16:16 just a spinning disk and the spinning airfoil.

1:16:18 Because if you think about it,

1:16:19 everything we looked at here depended on this disk flying forward.

1:16:23 And you see, I've got some arrows

1:16:25 on the ground here for wind coming at the disk.

1:16:28 Well, if you think about it, If this disk is flying and we're spinning it,

1:16:33 we're right-hand, back-hand, we're spinning it.

1:16:36 So it's moving forward into the wind and it's spinning, right?

1:16:40 So what that means is one side of the disk is spinning forward like this, right?

1:16:46 So you have the radius and the rotational velocity.

1:16:50 And on this side, you have the same thing.

1:16:52 You have the radius and the rotational velocity.

1:16:54 So this side is going forward and this side is going backwards.

1:16:57 But we have the wind that we have add in as well.

1:17:00 So if you think about it on this side,

1:17:02 if you have the velocity of the wind plus the forward velocity of the disk,

1:17:07 it's like that side is going faster.

1:17:10 But on this side, if you have the velocity

1:17:12 of the wind and the retreating velocity of the disk,

1:17:15 it's like this side is going slower.

1:17:18 So we have an asymmetric wind velocity on the disk,

1:17:22 which means if you have asymmetric wind, you're going to have asymmetric lift.

1:17:28 If it's flying faster on this side,

1:17:30 so it's going to lift up more or try to lift up more.

1:17:33 It's flying slower on that side, it's going to try to decrease.

1:17:35 So what I think is you have what's called the advance ratio.

1:17:40 This is something Dr.

1:17:40 Potts wrote about in his paper.

1:17:42 But what I think is so fascinating about

1:17:45 this is originally on our model of lift,

1:17:48 we had this longitudinal axis from the front all

1:17:52 the way to the back of the disk, right?

1:17:54 And we imagined that the lift vector went right through that, right?

1:17:59 So We've got this longitudinal axis,

1:18:01 and we imagined that the center of lift was along that longitudinal axis,

1:18:07 and the lift displacement over this side was off to the side like that, right?

1:18:12 But because of this asymmetric lift we're talking about,

1:18:16 I think it's even more complicated than that.

1:18:19 I don't think...

1:18:20 I'm going to park those right there.

1:18:22 I don't think that the lift is happening right on this axis.

1:18:25 I think it's happening a little bit more on the advancing side.

1:18:28 So it might be out We're like this, okay?

1:18:32 But as it goes forward, it's rotating around.

1:18:34 We might not come through the exact center

1:18:36 of mass or center of gravity of the disk.

1:18:39 We might actually come like this right here.

1:18:42 But maybe as it slows down in rotation towards the end of the flight,

1:18:46 maybe it comes over like that.

1:18:47 Who knows what's happening?

1:18:49 Maybe it's some fancy curve.

1:18:51 Maybe it does go through the center.

1:18:53 I don't know.

1:18:54 But what I do know is there's

1:18:56 more happening than what we initially thought about.

1:19:00 Because it's rotating.

1:19:01 It has to be different.

1:19:02 Another thing to think about is disk golf players know this.

1:19:06 If you have a brand new disk and you hit

1:19:08 a tree like I do all the time, what happens?

1:19:11 That edge on the disk right there gets what's called beat in.

1:19:16 The edge of that disk starts to become dented,

1:19:19 and what happens is you create turbulence over the top.

1:19:23 Dr.

1:19:24 Potts explained this to me.

1:19:26 He said that once a disk becomes beat in, you get this turbulent layer of flow,

1:19:31 which makes the flow want to stay attached to the disk longer.

1:19:35 Because that attached flow stays attached longer,

1:19:37 the center of lift is going to stay back,

1:19:40 which makes it behave more under stable, which I think is fascinating.

1:19:44 There's so much going on here.

1:19:46 Dr.

1:19:47 Potts and I even talked about the leading edge of the disk.

1:19:49 If the parting line was higher, it was more over stable.

1:19:52 If it was lower, it was more under stable.

1:19:54 Dr.

1:19:55 Potts and I talked about that as well.

1:19:56 And it has to do with the attachment of the center lift

1:20:00 and also the front edge and how it drives the air up or down.

1:20:03 And now I also have to say this.

1:20:07 Back in the day, the early pioneers

1:20:09 of disk golf did not consult aerospace engineers,

1:20:12 the kinds There's a lot of people that would use slide rules like this.

1:20:17 And the reason I know that is because when you have an aircraft,

1:20:21 as we discussed earlier,

1:20:22 when the center of pressure is behind the center of mass,

1:20:26 you get a riding moment.

1:20:28 And so it is a stable aircraft, right?

1:20:31 But if that center of pressure ever moves forward of the center of mass,

1:20:34 you get that moment to work against you, and you are more unstable.

1:20:39 So the stability of the aircraft has to do with where

1:20:42 the center of pressure is in relation to the center of mass.

1:20:45 Okay, so when we start looking at disk, let's think about it.

1:20:50 So there's one type of disk, when the parting line is lower,

1:20:53 the air will flow over the top,

1:20:55 which means the center of pressure stays behind the center of mass longer.

1:20:59 You have a more stable disk.

1:21:01 Conversely, when you have a disk with a higher parting line,

1:21:05 that air gets driven down, and among other things that come into play,

1:21:09 the center of pressure gets pulled forward of the center of mass.

1:21:13 So if you think about our riding

1:21:15 moment working against us in an unstable aircraft,

1:21:18 which of these two is more unstable?

1:21:20 Yeah, that one right there is the more unstable aircraft between the two disk,

1:21:25 which is odd because that is referred

1:21:28 to as an an over stable disk in the community.

1:21:33 What does this even mean?

1:21:34 It doesn't make sense.

1:21:36 Over here, when you have the center of pressure behind the center of mass,

1:21:40 what do people call that?

1:21:41 An under stable disk.

1:21:44 It does not make sense to an aerodynamicist.

1:21:47 It doesn't make sense.

1:21:48 But does it make sense to an amateur who

1:21:50 might be picking up a disk for the first time?

1:21:52 Well, which of these two make more sense to give an amateur?

1:21:56 I heard from the pros.

1:21:57 If you want a person to enjoy disk golf for the first time,

1:22:00 you give them a more under stable disk.

1:22:03 Why does that make sense?

1:22:04 Because in modern aircraft, if it's an under stable aircraft,

1:22:08 we have to incorporate fly by wire technology to even be able to fly the thing.

1:22:12 A more under stable disk is not what you

1:22:15 would inherently think needs to go to a newbie.

1:22:18 So this is what I propose.

1:22:20 I think these words are exactly wrong,

1:22:25 not only from an aerodynamics perspective,

1:22:29 but from a let's go play this golf perspective.

1:22:32 Because if you think about it, you want something that makes sense.

1:22:36 And if you've ever tried to explain these terms

1:22:38 to somebody playing with you, you know it's hard.

1:22:41 So that leaves us with the question, what should these words be?

1:22:45 And I talked to Dr.

1:22:46 Potts about it.

1:22:47 He and I were batting around the word roll, because if you think about it,

1:22:50 when you throw a disk, it's going to roll one way or the other.

1:22:53 So we talked about maybe under roll,

1:22:55 because it rolls under the direction you throw it,

1:22:58 or over roll, But you still have the issue

1:23:00 with over and under, which one is which.

1:23:03 In golf, you have a hook and a slice, and that makes sense,

1:23:06 but we don't really have those terms in disk golf.

1:23:09 So when they were coming up with these in the late '70s and '80s,

1:23:12 it was clear that these terms were established in the '90s

1:23:15 because we have literature that says that, this is exactly wrong.

1:23:20 However, in the modern day, we have the ability to change this.

1:23:24 And I know this because disk golf is rooted heavily in the aerospace community.

1:23:30 You've got Oak Grove out at Jet Propulsion Lab in California,

1:23:33 Bronze Springs near Marshall Space Flight Center.

1:23:35 These were some of the first courses to exist.

1:23:38 So the roots for technical accuracy go deep in the disk golf community.

1:23:43 So I think it's just time to revisit these terms,

1:23:46 and it needs to be something that's agreed upon

1:23:49 by everyone because this is a sport for everyone.

1:23:51 Okay, I said the thing.

1:23:53 So you can't just straight up design a disk

1:23:56 that looks like a certain way and like, Oh, it's going to behave this way.

1:24:00 At some point, it makes sense just to make a disk and throw it.

1:24:02 [P] Exactly.

1:24:03 It's really complex.

1:24:05 And that's how golf disk have evolved.

1:24:09 They've evolved because it started with whatever they had initially,

1:24:13 and then they slowly curved the upper surface and they've,

1:24:20 in terms of driver disk, I guess I'm talking now,

1:24:22 and they've elongated the rim and they've reduced

1:24:26 the cavity and they've just seen what effects that has.

1:24:30 Then they've sent it out to all

1:24:32 their players within their sponsorship team or whatever,

1:24:35 and they get them to throw, Do you like it?

1:24:38 How does this...

1:24:39 And then they analyze what he actually does on the fairway.

1:24:45 So they really are very much changing

1:24:48 the designs that they've got currently and tweaking them.

1:24:53 And then they're giving them to the players

1:24:55 and then trying to learn what the effect that has to then see how they translate

1:25:00 that back into knowledge to then progress golf design, disk golf design forward.

1:25:08 [D] So the fact that disk golf disk

1:25:11 technology is evolving and progressing is happening now.

1:25:14 Listen to what Brad and Chad had to say in response to one of my questions.

1:25:18 [B] That turn and fade is a key too.

1:25:20 [D] But there's two things when I throw a disk.

1:25:23 I've got the forward velocity, and I have the rotational velocity.

1:25:28 [B] If we can maximize that rotational momentum,

1:25:31 that will reduce that turn and fade.

1:25:34 If you think about it, that turn and fade is wasted energy

1:25:37 that could be straightened out to travel farther.

1:25:40 If you're spending all that time in the air, turning and fading,

1:25:45 All that drag during that long path is shortening your potential distance.

1:25:49 If you can increase that MOI, you are essentially pulling out that S-curve,

1:25:54 so to speak, and making that travel farther.

1:25:57 That's really the [C] And also just the predictability.

1:26:00 In disk golf, you want accuracy, not just distance, but accuracy.

1:26:04 So that turn and fade is a little bit of instability in that flight.

1:26:09 But if you increase that moment of inertia or that gyroscopic stability,

1:26:13 it's more predictable in its turn and fade phase,

1:26:15 a little bit more consistent and reliable.

1:26:18 [D] Okay.

1:26:19 Technically, this video is sponsored by MVP,

1:26:22 so it's an ad, to even mention them.

1:26:26 But I don't want this part to feel like an ad.

1:26:28 I want this to feel like a scientific

1:26:30 inquiry because that's where I'm at with it.

1:26:32 So I chose to say yes to MVP when they

1:26:34 reached out to Smarter Every Day years ago because they said,

1:26:37 Hey, we want you to talk about disk golf because we love disk golf.

1:26:40 And I was like, I like disk golf.

1:26:41 I'm not a pro like these people we interviewed in this video, but I love it.

1:26:45 It's really fun.

1:26:46 And I like science and aerodynamics.

1:26:48 So it was like our Venn diagrams were perfect.

1:26:50 So what I'm about to tell you is interesting.

1:26:53 And I make no claims.

1:26:55 I'm just telling you I'm going to investigate this further,

1:26:57 and there will be opportunities in the future

1:26:59 for you to to investigate this further.

1:27:01 So this is a disk golf driver made by MVP Disk Sports.

1:27:05 This is a custom Simon Lozat driver.

1:27:08 You'll notice there's a black rim along the outside.

1:27:10 This is an overmold.

1:27:11 This is MVP's differentiator.

1:27:14 They claim that By putting more mass on the outside,

1:27:17 they are increasing the moment of inertia,

1:27:19 which gives you more angular momentum,

1:27:21 which makes the disk not want to turn and fade as much.

1:27:25 You just heard Brad and Chad talk about that.

1:27:27 Well, we've been talking about this for years, them and I.

1:27:30 We've been talking about it offline.

1:27:32 And one of the things I mentioned is, Hey,

1:27:34 you guys really should look into these devices to measure the moment of inertia.

1:27:39 They were doing it already.

1:27:41 So I worked with them to find a device

1:27:45 to measure disk golf disk moment of inertia around this axis.

1:27:49 And here's a clip of them testing a new device.

1:27:52 Basically, it shakes the disk and it can measure the rotational inertia,

1:27:57 more or less, and you can get the moment of inertia.

1:28:00 It's really fascinating.

1:28:01 I think it would be awesome that they're

1:28:03 already laser engraving the mass on the disk.

1:28:06 If you remember in the production video,

1:28:08 we got to see them put a disk in the laser machine

1:28:11 and use a laser to engrave the amount of grams on the disk.

1:28:15 I think it would also be cool to put

1:28:17 the number of the moment of inertia on the disk,

1:28:20 which brings me to their new prototype.

1:28:23 Mvp has a prototype disk.

1:28:26 You'll notice that the outer rim is much smaller than the drivers.

1:28:30 So the outside of this disk is

1:28:33 impregnated with copper powder so that it's heavier,

1:28:36 but the inside has what they're calling micro

1:28:39 bubble technology in the plastic, so it's lighter.

1:28:41 So you're taking the mass from the inside

1:28:43 of the disk and you're pushing it out to the outside.

1:28:46 So you're increasing the moment of inertia while maintaining,

1:28:49 hopefully, the same mass.

1:28:50 I think this is fascinating.

1:28:52 What I can tell you is that in my front yard tests,

1:28:56 this disk flies further and straighter.

1:28:59 I'm not I'm not an expert,

1:29:01 but what I can tell you is it's a very interesting disk to throw,

1:29:05 and it's very similar in a normal driver,

1:29:09 only it doesn't roll and turn and fade as much.

1:29:12 It's fascinating.

1:29:13 In summary, when you throw a disk golf disk there

1:29:16 is a three-dimensional saddle that you have to ride and find.

1:29:21 And you do that by how you hold the disk, how you throw the disk.

1:29:26 But there's this fine turn and fade,

1:29:28 and there's this perfect saddle point that if

1:29:31 you're a good player, you can find it.

1:29:33 And I hope this video helped you understand where

1:29:36 it is and what you can do to change it.

1:29:39 For me, I learned that I have to get my arm up

1:29:41 and then the nose actually down when I'm throwing for distance at the beginning.

1:29:44 No clue that was a thing, but I learned that.

1:29:47 It's fascinating.

1:29:48 So I hope you incorporate some of the stuff you learned in this video

1:29:51 to improve your disk golf game or just your love of the sport.

1:29:54 And you get to appreciate when you see a disk flying and you get to know,

1:29:59 oh, that's what's happening.

1:30:00 The pitching moments in the back, which is driving it right.

1:30:03 And then it moves forward, and then it's going back to the left.

1:30:07 Just knowing that is a beautiful thing, and I'm excited about it.

1:30:11 So I hope you enjoyed this video.

1:30:13 I want to say thanks to MVP Disk Sports for sponsoring this video.

1:30:17 I want to say thanks to Dr.

1:30:18 Potts and everybody else in this video for teaching me so much.

1:30:21 I hope you will stick around for an upcoming video when we actually test

1:30:25 some of this stuff with engineering tools that I am not willing to reveal yet.

1:30:30 But I'm excited for an upcoming video where we're going

1:30:33 to learn even more about how disk golf disks fly

1:30:36 and maybe test some of these prototypes and understand if

1:30:40 this gyro technology is the future of disk golf technology.

1:30:44 I think it might be, and I think it's fascinating to learn.

1:30:47 I also think there's other things you can do to improve these disk,

1:30:50 and I've been thinking about that as well.

1:30:52 Anyway, I absolutely love this.

1:30:53 It's fascinating to me.

1:30:55 I would be doing this stuff even if YouTube wasn't a thing.

1:30:57 I hope that comes through in the videos.

1:30:59 I certainly feel that.

1:31:00 But thank you to everybody that supports

1:31:02 Smarter Every Day on Patreon at Patreon.com/smartereveryday.

1:31:05 It's a huge deal.

1:31:07 And thank you to you for watching.

1:31:09 This was a long video, and I hope you enjoyed it.

1:31:11 Anyway, that's it.

1:31:12 I'm Destin.

1:31:13 Stay tuned for video three.

1:31:15 You're getting Smarter Every Day.

1:31:16 Have a good one.

1:31:17 Bye.

1:31:29 They just crane operated a bathroom over a car

1:31:32 and look at the back of the crane.

1:31:39 It's so cool.

1:31:51 Couldn't make it.

1:31:52 You couldn't make it?

1:31:53 What?

1:31:55 Let's go get Smarter Every Day.

1:31:59 Was it?

1:32:00 What was that?