Speaker 1: Welcome to Stuff You Should Know, a production of five
Speaker 1: Heart Radios How Stuff Works. Hey, and welcome to the podcast.
Speaker 1: I'm Josh Clark, there's Charles W. Bryant, and there's Jerry
Speaker 1: Woosh Roland over there is just getting worse and worse.
Speaker 1: This is Stuff You Should Know podcast wind Tunnel a
Speaker 1: dish m Aren't you glad we're not in the same
Speaker 1: room so that you couldn't smell my breath When I went, yeah,
Speaker 1: my daughter's gotten a bad habit of doing that, and
Speaker 1: she thinks it's funny. I'm like, it's really not of
Speaker 1: what of like breathing and someone's nose on purpose, like
Speaker 1: right in your face, and like no one, no one
Speaker 1: likes that. Yeah, she's she's just entered the age of
Speaker 1: what five to where that's something people do. Yeah, not
Speaker 1: not funny. Ever, I'll tell you what. These masks that
Speaker 1: we're all wearing, this is a real reckoning with your breath.
Speaker 1: THO wouldn't it? Oh my god, it's funny. It's like
Speaker 1: a it's like an hour by our slide into despair.
Speaker 1: You're like, I don't remember eating garlics. Yeah, it's like
Speaker 1: in the morning is like, oh man, this is great,
Speaker 1: and I love this mask. And later in the day
Speaker 1: you're you need that toothbrush. Yes, it's true. They say
Speaker 1: you can't smell your own breath and they are wrong.
Speaker 1: And I'm brushing my teeth now more than other because
Speaker 1: I'm scared to go to the dentist. Yeah. Same here.
Speaker 1: I'm also flossing like a mad person too. You're flossing
Speaker 1: right now, I can, I can hear it. Wow, that
Speaker 1: was the most pc thing I've ever said, is what
Speaker 1: I'm flossing like a mad person, not a madman. And technically,
Speaker 1: I guess not. I would have said like a mentally
Speaker 1: ill health person. Yeah, I think that's even bad. Who
Speaker 1: knows these days, right, that's right. Let's talk about wind tunnels. Okay,
Speaker 1: so we're talking wind tunnels. Um, and I had no
Speaker 1: idea how interesting wind to thos were. I had an
Speaker 1: inkling that they were going to that there was like
Speaker 1: more to wind tunnels than people realize, which is absolutely true. Um,
Speaker 1: but they're they're pretty, they're deep cut. Yeah, I mean
Speaker 1: there was way there's way more to them, and you
Speaker 1: can do way more with them and learn way more
Speaker 1: from them than I thought because my experience with wind tunnels.
Speaker 1: Like most people is seeing the cool TV commercial with
Speaker 1: the with the like green smoke flying over the car
Speaker 1: to demonstrate how aerodynamic it is. And to be sure,
Speaker 1: that is a very big part of what they use
Speaker 1: wind tunnels for. Yeah. Yeah, and Chuck, you know, you
Speaker 1: and I were in a commercial in a wind tunnel.
Speaker 1: I thought you might bring this up. That was a
Speaker 1: wind tunnel. Technically that that um indoor skydiving thing is
Speaker 1: a type of wind tunnel. It's a vertical wind tunnel. Yeah,
Speaker 1: if you guys haven't seen that. It's been a while
Speaker 1: since we promoted these things. We used to do these
Speaker 1: little shorts. Um no, this was different. Well no, but
Speaker 1: these were based on the shorts. Yeah. Yeah, we did
Speaker 1: these little shorts that we called interstitials. Did a lot
Speaker 1: of them, and to me, it's like the best video
Speaker 1: work we've ever done as a team. Um, I love
Speaker 1: don't be done. But that was just you. Um well,
Speaker 1: it was great. It was you in the room and
Speaker 1: it was this chair and you sort of played a character. Yes,
Speaker 1: go on, And some people have problems with the character
Speaker 1: because I thought you were making fun of a certain
Speaker 1: kind of person. Sure, that wasn't true. It was all
Speaker 1: very kind hearted and just funny. That was really great,
Speaker 1: Thank you. Sure. Uh and that chair still here in
Speaker 1: the office, right, Yes it is, and I believe my
Speaker 1: outfit still is. I'm waiting for the Smithsonian calm. So. Yeah.
Speaker 1: We did this um TV commercial for Toyota that was
Speaker 1: very much in the vein of those interstitials where we
Speaker 1: were in just all over Atlanta, in various parts of
Speaker 1: Atlanta doing funny things. That was l A. Remember well, no,
Speaker 1: this was again talking about the original interstitiause I'm so confused.
Speaker 1: Then when we went to l A, we did the
Speaker 1: same thing. We replicated that style in Los Angeles and
Speaker 1: long the upshot of this all is we end up
Speaker 1: in a indoor uh skydiving facility having a conversation like
Speaker 1: you know, a normal conversation or trying to That was
Speaker 1: the gig, the gig. That was the gag. That was
Speaker 1: the bit. Yeah, and you get slung against the side
Speaker 1: of it at the end, which is kind of the
Speaker 1: funniest part. Yeah, it really really was. It was supposed
Speaker 1: to be an outtake and they made it an intake.
Speaker 1: Those things were very difficult to uh if you've never
Speaker 1: done one before. There, I mean, it was fun and
Speaker 1: kind of cool, but it's not easy. You don't just
Speaker 1: go in there and be like, hey, I'm floating. No,
Speaker 1: it's really really hard actually, yeah, like you're working every
Speaker 1: muscle in your body. It's kind of like water skiing
Speaker 1: looks fun too. Yeah you were good at it. I
Speaker 1: was not very good. I was okay, but it was
Speaker 1: it was tough. Yeah. So, um, that was what would
Speaker 1: be technically called a vertical wind tunnel, right, And they
Speaker 1: actually used those two to research spin. Um, Like, when
Speaker 1: something goes in, uh, like a tail spin, like a
Speaker 1: helicopter goes in a tailspin, they would use a vertical
Speaker 1: wind tunnel to test for that kind of thing. Right.
Speaker 1: But the wind tunnels we kind of more think of
Speaker 1: are the horizontal tubes where you see a car or
Speaker 1: something like that having the cool smoke blown over it
Speaker 1: for a commercial. But they're very useful. Um, and this
Speaker 1: is something I didn't really know I kind of I
Speaker 1: kind of just thought they were all these big giant
Speaker 1: things that you would put an actual car in. Most
Speaker 1: wind tunnels are these little desktop models that you use
Speaker 1: in a science lab that have a scale model that
Speaker 1: you're using instead of the actual thing, right, which which means, yeah,
Speaker 1: that you're using a smaller version, but that is precisely
Speaker 1: scaled down. It looks the right size, doesn't quit. I'm
Speaker 1: sure this plane will fly, this is close enough. But
Speaker 1: what's neat about that is that they can scale this
Speaker 1: thing down. They can subject it to, you know, the
Speaker 1: same conditions as they would a full size model. But
Speaker 1: then they can correct for the data for that whatever
Speaker 1: with the numbers they're getting the output, they can correct
Speaker 1: to scale it back upwards. Um, just using math. Because
Speaker 1: if there's one thing that goes hand in hand with
Speaker 1: wind tunnels, it is math, friends, Because the whole point
Speaker 1: of wind tunnels is to study aerodynamics, which is the
Speaker 1: flow of air or gas is over an object. Um
Speaker 1: And in this case it's a stationary object and the
Speaker 1: wind is moving. But what they're really doing is simulating
Speaker 1: that object moving out there in the real world into wind.
Speaker 1: And I mean, that's a wind tunnel. And when you
Speaker 1: put it like that, it sounds very simple. They are
Speaker 1: not simple at all. There's really nothing about wind tunnels
Speaker 1: that's simple, from their construction, to their cost, to what
Speaker 1: they're used for, to all of the different variables and
Speaker 1: conditions that they can test for there they grew step
Speaker 1: in step, hand in hand with the aviation industry, Like
Speaker 1: we probably wouldn't have an aviation industry right now without
Speaker 1: wind tunnels. Um and that should kind of give you
Speaker 1: an idea of how complex the stuff that people are
Speaker 1: doing in wind tunnels is, or the data they're extracting
Speaker 1: from these wind tunnels tests. It's not just like, look
Speaker 1: that cool green smoke bending over the car. That's for
Speaker 1: for yokels like you and I watching ads while you know,
Speaker 1: in between golf, you know, like you're watching golf and
Speaker 1: the ad comes on my brain. Is the best part
Speaker 1: of golf, The ads I've actually kind of gotten. Are
Speaker 1: you watching golf now? Yeah? Kind of here there. It's
Speaker 1: not something I seek out. But and it's not for
Speaker 1: the golf. I could care less about the golf. It's
Speaker 1: the it's the views, it's the shots. The golf courses
Speaker 1: are just they have the most amazing backdrops and it's
Speaker 1: just so tranquil and calm. It's really something. Yeah, you know,
Speaker 1: I live right down the street from the legendary East
Speaker 1: Lake Country Club in Atlanta, Bobby Jones Course, and been
Speaker 1: to one day of that one tournament. That's the only
Speaker 1: time I've actually been to a professional golf tournament and
Speaker 1: you know, I stood there twelve feet from Tiger Woods
Speaker 1: and the tea box is pretty pretty neat. Wow, like
Speaker 1: just to see because I played golf a lot growing
Speaker 1: up and it's a hard sport and to see someone
Speaker 1: do it uher perfectly right in front of your face
Speaker 1: with that much power, was it was. It was really impressive.
Speaker 1: You know what, what would really help Tiger Woods swing
Speaker 1: if they put him in a wind tunnel, put some
Speaker 1: green smoke in the wind and watch them swing. They
Speaker 1: could tell him how to do it better. You want
Speaker 1: smoke him smoke that's right, that's right. Shout out to
Speaker 1: our Guard Detroit crew from the day. Al Right, So
Speaker 1: if you want to go back in time and talk
Speaker 1: about human flight, you're gonna look at things like Da
Speaker 1: Vinci's ornithopter and kind of a lot of early stabs
Speaker 1: at flying were humans looking at birds and thinking, well,
Speaker 1: if we're gonna fly, we're gonna have to learn how
Speaker 1: to flap wings really fast. And it made sense. I
Speaker 1: guess if you're looking at birds, they're the only thing
Speaker 1: flying around. Uh, it would make sense that that's where
Speaker 1: they would go. But they knew early on, regardless of
Speaker 1: the flapping, that they needed to understand wind and how
Speaker 1: wind worked with wings. And so they started going to
Speaker 1: these little hills and mountains and they started going to
Speaker 1: caves that had you know, they were looking for some
Speaker 1: sort of predictable, constant wind so they could do some
Speaker 1: early testing. And they realized, you just can't do it
Speaker 1: with mother nature. You can't get a consistent wind, not
Speaker 1: enough to get real data out of it and do
Speaker 1: that math that we need so so drastically to make
Speaker 1: this possible. Right so, and and initially we got that
Speaker 1: assist from birds and that we knew wings had to
Speaker 1: be involved. That the whole flapping thing really kind of
Speaker 1: threw things off for a while. But because we knew
Speaker 1: that there had to be wings, we knew that there
Speaker 1: had to probably be some ideal or optimum shape of wings.
Speaker 1: And that's really where wind tunnels first got their start,
Speaker 1: wasn't testing different shape of wings or air foils. And
Speaker 1: there was a guy back in seventeen forty six named
Speaker 1: Benjamin Robbins who created a wiry arm um, which is
Speaker 1: basically like a It was a centrifuge basically is what
Speaker 1: he created. He had a hard time picturing this, and
Speaker 1: there's only there's this one very rudimentary sketch that made
Speaker 1: it even more confusing. Okay, so just just imagine you
Speaker 1: have like a pole coming out of the ground vertically
Speaker 1: and you have an arm attached to that pole, and
Speaker 1: the pole can spin around in a circle like a centrifuge,
Speaker 1: like one of those G force testers that they have
Speaker 1: at and like, um, like astronaut training, you know what
Speaker 1: I'm saying. Yeah, yeah, yeah, that thing. This is what
Speaker 1: that guy invented. But it was like with wood and
Speaker 1: in the dirt. It wasn't and it didn't go that fast.
Speaker 1: But you could have fixed a like a wing type
Speaker 1: that you were testing to see if it worked well
Speaker 1: to the end of it and push it through the air.
Speaker 1: And it didn't really help this guy figure out what
Speaker 1: wings style or size was the best. What it helped
Speaker 1: him figure out is that it doesn't have that much
Speaker 1: to do with anything with flapping. We don't need to
Speaker 1: be wasting our time inventing machines that that flap their wings,
Speaker 1: because that's not it. It's all about this thing called
Speaker 1: lift and drag and the proportion between those two. And
Speaker 1: if you can figure out how to get more lift
Speaker 1: and decreased drag. Then you can you can really make
Speaker 1: some you can fly basically, And this was the very
Speaker 1: first inklings of that that Benjamin Robbins came came up with. Yeah,
Speaker 1: and what I saw was that Robbin's really kind of
Speaker 1: pinpointed drag, like the shape is super important. And then
Speaker 1: after him, Sir George Cayley had his own whirling arm
Speaker 1: and he's the one that really figured out lift was
Speaker 1: a key. After they realized the shape of the thing
Speaker 1: matters the um more than the shape, like the size
Speaker 1: of it matters. Size does matter, especially when you're flying,
Speaker 1: especially when you're flying, and uh that if you could
Speaker 1: just get a quick enough takeoff, you don't need to
Speaker 1: flap at all. All you need is a lot of
Speaker 1: speed at first, which they could have also gotten frankly
Speaker 1: by if they would have kept looking at birds and
Speaker 1: realized they eventually stopped flapping, they might have realized, oh,
Speaker 1: you actually don't need to flap the whole time. You
Speaker 1: can glide if you've got enough speed, right and and well,
Speaker 1: actually a lot of the early flying machines were gliders.
Speaker 1: It was one of the the Wright brothers were not
Speaker 1: the first people to UM engage in in human flight.
Speaker 1: There is a monk named Elmer of Malmsberry who has
Speaker 1: the first recorded human flight back in ten fifty c
Speaker 1: E not b C and um he he You know,
Speaker 1: that was almost a thousand years before the Right Brothers UM.
Speaker 1: But the Right Brothers are credited with with UM the
Speaker 1: like an engine powered flight human flight. Right, So they
Speaker 1: they were dabbling in what's what Kaylee and Robbin's well,
Speaker 1: Kaylee especially figured out that you need thrust and there's
Speaker 1: just nothing around that's light enough to produce enough thrust.
Speaker 1: So Kaylee actually gave up and went and joined parliament
Speaker 1: for a while before he finally created a flying machine.
Speaker 1: Fifty years before the Right Brothers. He made his UM.
Speaker 1: He made his coach driver test pilot it, and the
Speaker 1: coach driver was so scared even though the flight was
Speaker 1: successful that when he landed he was like, I quit,
Speaker 1: I quit. I'm not. I don't work for you anymore. Yeah,
Speaker 1: but George Kayley's very much overlooked figure in the history
Speaker 1: of flight. He apparently figured out the general shape um
Speaker 1: of a modern airliner back in Yeah. Alright, I say
Speaker 1: we take a break, we'll come back and talk about
Speaker 1: the first wind tunnel right after this. Alright, so Kaylee
Speaker 1: has these whirling arms going terrible name, but it worked out. Uh.
Speaker 1: Then enter a man named Frank h Win him. He
Speaker 1: was another Englishman and he was in the Aeronautical Society
Speaker 1: of Great Britain, and he said, guys, we need or
Speaker 1: excuse me, gentlemen, we need a wind tunnel, and we
Speaker 1: need it bad. And so in eighteen seventy one he
Speaker 1: had the very first wind tunnel. Was twelve ft long,
Speaker 1: about eighteen inches square, with a forty mile wind, which
Speaker 1: is pretty good. It was. It consisted of your daughter going,
Speaker 1: oh god, stinky has went dunne her breath. Isn't that
Speaker 1: stinky yet? Kids don't really start to stink until later,
Speaker 1: I think, yeah, until later. But the winds were powered
Speaker 1: by a steam fan at the end of the tunnel,
Speaker 1: and it worked pretty well. He was able to get
Speaker 1: that leading edge of the airfoil and move it up
Speaker 1: and down and change his angle angle of attack and
Speaker 1: kind of see what shaped, uh and what angles worked
Speaker 1: best with to get the best lift. But it was
Speaker 1: still sort of choppy, and it was rough around the edges.
Speaker 1: And if you really want to make this you know,
Speaker 1: if you want to fly safely, you got to have
Speaker 1: a really really really consistent, very smooth wind to work
Speaker 1: with to get that data. And they still didn't have
Speaker 1: one at this point. Now they still didn't, but they
Speaker 1: were advancing by leaps and bounds here that people were
Speaker 1: building their own wind tunnels. Because up to that point,
Speaker 1: if you had in a design for an airfoil, for
Speaker 1: like a wing size or shape, you had to build
Speaker 1: it and then go take it out into nature and
Speaker 1: test it and hope for the best, and it was
Speaker 1: really expensive, really time time consuming. With your own wind
Speaker 1: wind tunnel, you could make a model of the shape
Speaker 1: and test it out yourself and then see this is
Speaker 1: actually worth pursuing, or this as junk, and that's it.
Speaker 1: That's what our dear beloved heroes, the Right brothers did
Speaker 1: in Ohio outside of Dayton, Lorville and Wilbur Wright Um
Speaker 1: built their own wind tunnel. These guys were just like tinkerers.
Speaker 1: They owned a bike shop, but they were so fascinating
Speaker 1: were following these developments in early flight that they just
Speaker 1: kind of got into it themselves and they built themselves
Speaker 1: a wind tunnel. They had like two different or two
Speaker 1: hundred different types of wings. I believe that they messed
Speaker 1: with selected the thirty best ones that they had developed
Speaker 1: in their wind wind tunnel of their own construction and
Speaker 1: design um And apparently I saw somewhere that by nine one,
Speaker 1: after their wind tunnel tests, the Right Brothers, a couple
Speaker 1: of bicycle repairment in Dayton, had the world's um most
Speaker 1: accurate data scientific data on on flying and wings in
Speaker 1: the world. And they'd come up with it entirely by themselves. Yeah,
Speaker 1: and here's the thing with these wind tunnels, especially early
Speaker 1: on in kind of still, it's not like they could
Speaker 1: use that wind tunnel and come out with a surefire
Speaker 1: product using math and uh and testing different designs and
Speaker 1: shapes and tilts and angles. But it was such a
Speaker 1: time saver and broken bone saver that you didn't just say,
Speaker 1: all right, well, I think this might work. Let's go
Speaker 1: and push our cousin off of a cliff or our
Speaker 1: coach driver or whatever and see if it works. They
Speaker 1: still had their failures, all of them did, But I
Speaker 1: mean it would have taken I mean, god knows how
Speaker 1: many more years if they didn't, like at least start
Speaker 1: from a point of likely success thanks to wind tunnels.
Speaker 1: But I mean, like, look at it. They went from
Speaker 1: they finished their wind tunnel tests in nineteen o one,
Speaker 1: they had their first powered flight in en three. Yeah,
Speaker 1: I mean that's so it's amazing two years and it
Speaker 1: definitely did accelerate it too. And so you can see
Speaker 1: from the outset that that aviation and wind tunnels just
Speaker 1: developed together, and wind tunnels developed aviation um. But the
Speaker 1: first wind tunnels, like you said, they had a really
Speaker 1: big problem, and that was the air that they produced.
Speaker 1: The stream of wind was very choppy, very turbulent, and
Speaker 1: your data was not necessarily reliable. It wasn't too terribly
Speaker 1: much better than say, going out into mother Nature and
Speaker 1: subjecting you know, the same model to those winds um
Speaker 1: And that's a big problem. So one of the first
Speaker 1: things that they figured out how to do was to
Speaker 1: make the wind smoother so that you could get a reliable, smooth,
Speaker 1: steady wind um in your wind tunnel whenever you wanted
Speaker 1: to use it. Yeah, and that's where we come to
Speaker 1: the modern tunnel, very very smooth airflow. And they have
Speaker 1: five basic sections of and they're you know, they're all different,
Speaker 1: but they have five basic sections. In a modern tunnel
Speaker 1: that's the settling chamber, the contraction cone, the test section,
Speaker 1: the diffuser, and the drive section. So we start out
Speaker 1: with this swirling air and it's a big choppy mess
Speaker 1: and it enters the tunnel and we'll talk about how
Speaker 1: in a second, because it's kind of cool, little counterintuitive,
Speaker 1: but it makes a lot of sense. Um it goes
Speaker 1: into the settling chamber, which does exactly what you think.
Speaker 1: It settles that air, straightens it out. They might have
Speaker 1: these little honeycomb holes or a screen or these panels,
Speaker 1: and that's just sort of the initial thing to sort
Speaker 1: of get it nice and smooth and moving in the
Speaker 1: same uniform direction. Yeah, and then it goes down. They
Speaker 1: step it down through that contraction cone, and that just
Speaker 1: I mean, it's like anything else. If you make the
Speaker 1: the tube smaller, it's going to increase that velocity of
Speaker 1: air flow. And that's where it gets to the test section,
Speaker 1: which is whatever. And the test section depends on what
Speaker 1: you're testing. If it's a desktop thing, the test section
Speaker 1: might be twelve inches long and you might have a
Speaker 1: tiny little model of an airplane wing in there, and
Speaker 1: that's where the actual thing you're testing is and where
Speaker 1: all the sensors are record all the data because you know,
Speaker 1: you've got your visual that you've got these windows so
Speaker 1: you can shoot TV commercials and you can look at
Speaker 1: the thing. But there's also all manner of sensors to
Speaker 1: pick up on all manner of UH data and observations. Yeah,
Speaker 1: I think that's really cool that they still you know,
Speaker 1: when they operate wind tunnels, they still watch through the
Speaker 1: window because there's a lot to be gained visually from
Speaker 1: from just human beings watching this stuff, and so you
Speaker 1: want to you want to watch it right, Yeah, for sure,
Speaker 1: especially when they got the green smoke thing turned on.
Speaker 1: So after it goes through the um, the test section
Speaker 1: enters a diffuser UM which kind of it slows things,
Speaker 1: slows things down UM and maybe just exits the whole thing.
Speaker 1: It's kind of the opposite of the contractor it just
Speaker 1: opens back up right exactly. So there's UM, there's there
Speaker 1: as far as breaking. There's a lot of different kinds
Speaker 1: of wind tunnels, as we'll see, but there's really kind
Speaker 1: of two categories too, broad categories. You've got open and
Speaker 1: closed circuit, and an open circuit is where you have
Speaker 1: wind going in on one end, going through the diffuser
Speaker 1: and the honeycomb in the test section and then coming
Speaker 1: out the other end blowing into the room and another
Speaker 1: with the closed circuit. It's just basically an oval and
Speaker 1: so when the wind is generated, it goes through the
Speaker 1: it goes through the test section out the back, but
Speaker 1: then bends around an oval track and then comes back
Speaker 1: around again and through the contraction coning into the test
Speaker 1: section again and again, and can just keep going rather
Speaker 1: than just blowing out the other side. Yeah, and here's
Speaker 1: the part that I said wasn't intuitive, but it's really
Speaker 1: kind of neat when you think about it. The drive
Speaker 1: section is where this fan is, and this is what
Speaker 1: it's just generating that air flow. And I always just
Speaker 1: thought a wind tunnel was a fan pointing at the thing.
Speaker 1: They're actually behind the thing, because you don't want to
Speaker 1: push air onto something, you want air being pulled over something.
Speaker 1: And it it just makes total sense, but you ever
Speaker 1: really thought about it, You just I always just pictured
Speaker 1: a big fan blowing at a car, but the fan
Speaker 1: would actually be behind the car and it's probably looping
Speaker 1: around and smoothing out this entire way and then being
Speaker 1: gently pulled over the car exactly. And in just the
Speaker 1: same way that the fastest way to cool off, say
Speaker 1: like a server room that you don't have good cooling on,
Speaker 1: you just throw a box fan the opposite way. So
Speaker 1: the boxman is blowing out into the regular room, but
Speaker 1: at the same time it's sucking the air, the hot
Speaker 1: air out of the out of the server room, and
Speaker 1: cool air is rushing into a place that hot air.
Speaker 1: So you're creating like an air flow that's much less turbulent.
Speaker 1: When the fan sucks the air out, it's much smoother
Speaker 1: than when it blows it in, which creates a lot
Speaker 1: more turbulence. And that was the big problem that was
Speaker 1: facing like the Right Brothers and some of those other
Speaker 1: early wind tunnel creators, is they their fans were blowing
Speaker 1: on the front of their models rather than having the
Speaker 1: fan behind it sucking the air over the models. Right.
Speaker 1: So these little models they're kept in place, sometimes around wire,
Speaker 1: sometimes around these middle poles. Uh sometimes I think they
Speaker 1: really super high tech ones use um super strong magnets
Speaker 1: to actually hold them in place, which is pretty cool.
Speaker 1: And then again you've got all these sensors all over
Speaker 1: the place attached to the model measuring I mean, we'll
Speaker 1: see it gets really really deep. But just at the
Speaker 1: outset you can measure like wind velocity and air pressure
Speaker 1: and temperature, and if you're talking about airplanes, roll and
Speaker 1: yaw and drag and lift, and I mean, you can
Speaker 1: kind of do anything you want in there. And if
Speaker 1: you have, like if you're testing an airplane or a
Speaker 1: scale model of the airplane you're gonna build, it's on
Speaker 1: something called the sting, which is a pole basically that
Speaker 1: goes into the airplanes bottom. But but then inside the airplane,
Speaker 1: the airplane is not attached to the pole. It's attached
Speaker 1: to something called a balance. And it's like all those
Speaker 1: sensors you just mentioned all in one instrument, like a
Speaker 1: cylinder tube, and as the airplane moves and pitches and
Speaker 1: yaws and rolls and and gallops and all that stuff,
Speaker 1: not gallops, So I made that part up. UM, it's
Speaker 1: it's acting on those sensors and the motion, the mechanical
Speaker 1: motion on those sensors is translated into an electrical impulse
Speaker 1: and that travels down the stinger into the computers which
Speaker 1: are picking up all of this data in real time
Speaker 1: and UM logging it and creating new new versions of
Speaker 1: the UH the model based on that stuff. It's pretty amazing.
Speaker 1: What's even more amazing that makes sense that that exists today,
Speaker 1: That's existed since like the forties or the fifties, and
Speaker 1: in much more primitive form, but essentially the same thing
Speaker 1: that we use today, the same kind of balance what
Speaker 1: has been around for decades. Wasn't there a Simpsons joke
Speaker 1: about y'all control? Yes, yeah, when they had one of
Speaker 1: those like backyard pockets now with yaw control and didn't
Speaker 1: like buzz Aldrin or something, say like, wow, look at
Speaker 1: that y'all control. I think so that was good stuff. Uh.
Speaker 1: Some other things that they measure, which you might not
Speaker 1: really think about existing is viscosity and compressibility, or the
Speaker 1: tackiness or the bounciness of the air itself. So when
Speaker 1: you're thinking about air blowing over a car driving down
Speaker 1: the road, you don't think of that air is like
Speaker 1: being sticky necessarily. But when that air is moving over
Speaker 1: the hood of that car, in the top of that
Speaker 1: car or the plane or whatever it is, Uh, those
Speaker 1: little molecules are gonna hit the surface and just very
Speaker 1: very briefly, they're going to cling to that surface, and
Speaker 1: that even for that brief brief amount of time. It's
Speaker 1: gonna create a little boundary layer of air next to
Speaker 1: the thing that you're trying to measure air flow over. Yeah,
Speaker 1: which is, like I said, a very big deal. And
Speaker 1: and yeah, an individual air molecule is going to stick
Speaker 1: for a nano second, just some ridiculously short amount of time.
Speaker 1: But there's so many air molecules that they essentially just
Speaker 1: replace each other as fast as they can move. And yes,
Speaker 1: they create this this this boundary layer. And as far
Speaker 1: as aerodynamics is concerned, your your say, your car blow
Speaker 1: go like driving through this wind that's that's sticking to
Speaker 1: it um now has a different shape. That boundary layer
Speaker 1: creates a different shape or extends it outward beyond the
Speaker 1: actual physical shape of the car. And so, yes, very
Speaker 1: much so. And then so so when you're trying to
Speaker 1: test like how fast the car is going to go,
Speaker 1: how many miles per gallon it's going to get that
Speaker 1: kind of stuff. That boundary layer makes a tremendous amount
Speaker 1: of difference because it changes physically changes the shape of
Speaker 1: this this thing when it's out there traveling at high speeds.
Speaker 1: So one of the great benefits of an air tunnel
Speaker 1: is you can test, like, what boundary layer is produced
Speaker 1: by this particular shape of this car under this condition.
Speaker 1: You know, if it's um humidity, but you know forty
Speaker 1: degrees ferrent height. Uh, and they're traveling at eighty miles
Speaker 1: an hour, what kind of boundary layers produced? Okay, well
Speaker 1: what about seventy five an hour at the sixty percent humidity.
Speaker 1: You can just change all these variables, and the wind
Speaker 1: tunnel allows you to simulate it in in in Basically, UM,
Speaker 1: get all this data in real time. UM. Just lickety
Speaker 1: split basically. Although one other thing, I just want to
Speaker 1: say this, we're making it sound like this is fast.
Speaker 1: This is actually, and has been, especially until the age
Speaker 1: of computers, very arduous work. Because if you wanted to
Speaker 1: change one variable, if you said, well, this headlight is
Speaker 1: actually causing way too much drag, you would have to
Speaker 1: switch that headlight out with your next model and run
Speaker 1: the same tests over and over and over again with
Speaker 1: the different different um conditions and log all that data.
Speaker 1: So it was really arduous before computers, and you kind
Speaker 1: of get the idea that aerodynamics as a field of
Speaker 1: study is really given over to computation. Like there has
Speaker 1: been a huge savior for that field and helped it
Speaker 1: along and saved a lot of people a lot of time. Yeah,
Speaker 1: and you mentioned things like humidity and temperature um. There
Speaker 1: are all different kinds of wind tunnels, and they can
Speaker 1: be very specific as to what they want to test
Speaker 1: or very broad, but they're they're all able to do
Speaker 1: things like that. You can dial in a temperature, you
Speaker 1: can dial in um atmospheric pressure if you want to
Speaker 1: see what something' is like on Mars, which they have
Speaker 1: to do if you want, like the Mars Rover to
Speaker 1: be successful. They can. They can ice up a plane
Speaker 1: wing just by introducing refrigerated air and spraying a mist
Speaker 1: of water that freezes and lands on the wing, and
Speaker 1: you can simulate all these different things humidity and temperature,
Speaker 1: And it's just amazing that that they thought to to introduce.
Speaker 1: You know, at first they started out probably just looking
Speaker 1: at aerodynamics of flow over a thing, but as they
Speaker 1: got more and more specific with their needs, they just said,
Speaker 1: you know that we can design these tunnels to kind
Speaker 1: of do anything we want to do, like recreate any
Speaker 1: and vironment you can think of. Basically, Yeah, it's true,
Speaker 1: and I mean like as as we started to build
Speaker 1: planes that go faster and faster. We started building tunnels
Speaker 1: that simulated that really high speed travel, and so we
Speaker 1: have hypersonic and supersonic um wind tunnels that don't use
Speaker 1: fans at all, but they use like bursts of compressed
Speaker 1: air that blow right onto the model. Those do blow
Speaker 1: at the thing instead of sucking behind it. Right. Um.
Speaker 1: But it's it's a huge release of of air that
Speaker 1: is traveling so fast it simulates you know, like a
Speaker 1: jet flying through you know, hundreds of you know, millions
Speaker 1: of miles an hour probably yeah, or hey, what's it
Speaker 1: like for a rocket human capsule too, uh to come
Speaker 1: back into Earth's atmosphere at the and and not burn
Speaker 1: up like they can simulate those temperatures. Yeah, there's one
Speaker 1: in I think North Carolina. No University of Texas at
Speaker 1: Arlington has something that can simulate that goes up Torees Ferren.
Speaker 1: It's crazy, man, it is. It's a wind tunnel for
Speaker 1: all in times of purpose. It's a wind tunnel. But
Speaker 1: they have built these things so that they can simulate
Speaker 1: basically any any climate. And you know, we talked about smoke,
Speaker 1: and it's always fun in those TV commercials to see
Speaker 1: the smoke blowing over the thing. And it's a nice
Speaker 1: visual to sell cars that look super aerodynamic in our
Speaker 1: super aerodynamic. But that visible flow isn't just you know,
Speaker 1: for the stoners in the lab department, like late at
Speaker 1: night to play around with, although they probably do that,
Speaker 1: but they flow visualization is a real technique. Um, you
Speaker 1: might just have colored smoke, you might have liquid, like
Speaker 1: a mist of liquid. You might have they use this
Speaker 1: colored oil sometimes that uh you can see like the
Speaker 1: wind pushing the oil along the surface of whatever model
Speaker 1: you're using, and then they've got these high speed cameras
Speaker 1: capturing all of it. And again it's just, um, it's
Speaker 1: another variable they can actually look at rather than just
Speaker 1: using numbers and data. Yeah, I saw one, um one
Speaker 1: was taking photographs of like two thousand frames per second.
Speaker 1: That speed it was, but it was they were testing
Speaker 1: like a rocket or something or model of it. Should
Speaker 1: we take a break, Yeah, let's all right. We'll be
Speaker 1: right back with more on wind tunnels right after this.
Speaker 1: So Chuck, I was like a lot of this really
Speaker 1: breaks my brain. It's one of those things we're like,
Speaker 1: oh yeah, I totally get this on the surface. Let
Speaker 1: me scratch a little deeper. I don't understand this at all.
Speaker 1: And the reason why is because you know, aerodynamics requires
Speaker 1: a lot of math and formula and all sorts of
Speaker 1: calculations that I'm not contrated that I'm not currently capable
Speaker 1: of doing that. But one of the things that I
Speaker 1: tried to shake down was when you do a scale
Speaker 1: model of something, do you have to scale down the conditions?
Speaker 1: And it turns out I wasn't the first one to
Speaker 1: think about this. Other people have, including people who work
Speaker 1: in wind tunnels, and apparently they do not do that.
Speaker 1: They will say, subjected to the same wind speed as
Speaker 1: they would like the full size one, but then they
Speaker 1: go back and use math to adjust um these that
Speaker 1: all the different variables and again, you know, we talked
Speaker 1: about pitch and y'all, role um, drag lift, all sorts
Speaker 1: of stuff. I'm sure quite a few things and variables
Speaker 1: that you and I haven't even come up with um
Speaker 1: or run across during our research. But in each one
Speaker 1: of these interacts with each other thing, right, So it's
Speaker 1: like one of those things where you know you have
Speaker 1: a eleven possible hoppings for a pizza and that creates
Speaker 1: twelve million potential combinations. It's a brain breaking amount of
Speaker 1: math involved exactly. So that's what they're doing. To scale
Speaker 1: it down and scale it up. They can say, oh, well,
Speaker 1: it produced this data. If we run it through these
Speaker 1: these you know, formula um like, we can show that actually,
Speaker 1: like it will have this effect in the in the
Speaker 1: real world. They're using that level of math. Anybody who
Speaker 1: can do that with math, I admire them deeply. If
Speaker 1: you're listening out there and you can do stuff like
Speaker 1: that with math, my hat is off to you because
Speaker 1: I will never be able to do that, and I
Speaker 1: admire you. Yeah, And you know what, we've taken some
Speaker 1: heat for kind of beating up on math a little
Speaker 1: bit is like boring because we were English and journalism
Speaker 1: guys and history guys. But uh, I've really come to
Speaker 1: appreciate math and doing this show. I'm no better at
Speaker 1: it and don't care to be, but I appreciate the
Speaker 1: You know, math is the one thing that doesn't care
Speaker 1: about what you think about it. It doesn't care about opinions,
Speaker 1: and there's no interpretation or nuance. It's just it's just math.
Speaker 1: And like what makes like to look at these to
Speaker 1: look at a math equation that would take a model
Speaker 1: of an airplane and a tiny little thing and a
Speaker 1: tiny wind tunnel and then say, well, now we just
Speaker 1: scale it up to this, and this is how you
Speaker 1: do it right, just multiplied by time. It makes me
Speaker 1: so nervous, But a real mathematician would be like, this
Speaker 1: is the last thing you should ever be nervous about,
Speaker 1: because it's it's just math. It's just right there. Well,
Speaker 1: it's just and they probably the idea of them of
Speaker 1: doing public speaking would probably scare the Jesus. And the
Speaker 1: thing is exactly like, different things attract different people, and
Speaker 1: that's great because that makes the world a lot more
Speaker 1: rich and complex that you have all these different people.
Speaker 1: If everyone was in the math, it would be a
Speaker 1: pretty boring place, or if everybody hated math would be
Speaker 1: a pretty boring place to Like, you need all different kinds,
Speaker 1: different strokes for different folks. Makes the world go round,
Speaker 1: I think, is the rest of them. All. Right, Let's
Speaker 1: talk about some of these wind as in the world,
Speaker 1: because they're amazing. NASA has one at Ames Research Center
Speaker 1: in San Jose or near San Jose, biggest in the world,
Speaker 1: biggest one hundred and eighty feet tall, dude four hundred
Speaker 1: feet long, and the test section on this thing is
Speaker 1: eight ft tall and a hundred twenty ft wide, so
Speaker 1: you can put a full size jet plane in that thing. Yeah.
Speaker 1: I saw that. I was like, well, what kind and
Speaker 1: they said seven thirty seven. Yeah, that's pretty good that kind, buddy,
Speaker 1: pretty pretty good size. So yeah, that's a I don't
Speaker 1: know if they call it this, but I hear here
Speaker 1: henceforth call it the Big Man with jam. Yeah. It
Speaker 1: uses six four story high fans, each of which is
Speaker 1: powered by six two thousand, five hundred horsepower motors. Six
Speaker 1: fans each as tall as a four story building. That man,
Speaker 1: that's amazing. A hundred and fifteen mile in our winds
Speaker 1: is where it tops out, yeah, which is pretty great.
Speaker 1: Um that there's also a lot apparently. I was reading one,
Speaker 1: um uh, some like blog posts I think on like
Speaker 1: a Formula one site, and they were talking about how
Speaker 1: like every single company, every single racing team has in
Speaker 1: its facility of full size wind one like it can
Speaker 1: hold a full size Formula one car the cost of
Speaker 1: like six million dollars or whatever. But they are um
Speaker 1: like cutting edge as far as um aerodynamic study is concerned. UM.
Speaker 1: And the reason why is because like if you can
Speaker 1: shave a second off of somebody's time just by reconfigure
Speaker 1: the engineers reconfiguring the shape of a fin or a
Speaker 1: tail or something like that. That's that you just it
Speaker 1: just paid for itself basically because it may have just
Speaker 1: one like the you know, good job there, Yeah, thank you.
Speaker 1: So there are NASCAR's obviously obviously got a couple of
Speaker 1: these things in North Carolina. The home of NASCAR Aerodin
Speaker 1: wind Tunnel. UM that is in North Carolina, and it
Speaker 1: tests full sized stock cars. There's no one called wind
Speaker 1: shear there. Um. This is a closed circuit tunnel that
Speaker 1: actually has a treadmill in it for cars. It's got
Speaker 1: a built in rolling road. Yeah, saw that in a
Speaker 1: few places, like BMW has one with the rolling road.
Speaker 1: You know what's interesting to me too, is so we
Speaker 1: saw that the aviation industry and UM and wind tunnels
Speaker 1: kind of grew hand in hand. The auto industry didn't
Speaker 1: really look up wind tunnels until about the fifties is
Speaker 1: when they really started running their cars through those, and
Speaker 1: they went, boy, these cars are not aerodynamic. Now look
Speaker 1: at it. Look at that yaw control. Though. Yeah, I
Speaker 1: love those old cars. Though I used my old Plymouth
Speaker 1: Valiant that I used to have. Um. This is obviously
Speaker 1: way before anyone ever thought of anything like anti lock breaks.
Speaker 1: And one of the most fun things I would do
Speaker 1: when I was driving with friends on an empty road
Speaker 1: late at night was get up to about fifty miles
Speaker 1: an hour and just slam on the brakes. It was
Speaker 1: so much fun, man, it was great. You would just go.
Speaker 1: You would slide about a hundred feet before finally coming
Speaker 1: to arrest. That was a great impression of slamming on
Speaker 1: the brakes too, by the way, it was good and
Speaker 1: you know it. It was like we called it the
Speaker 1: sled because it was just this big, heavy hunk of metal.
Speaker 1: It's not like I was sliding all over the road.
Speaker 1: I was just sliding very straight in a line. What's
Speaker 1: the opposite of aerodynamic that Plymouth Valiant? There you go, um,
Speaker 1: sluggish like a what sponge? Yeah, that's about right. So UM,
Speaker 1: I think we should wrap this up on the future
Speaker 1: of wind tunnels because people have been saying like, well,
Speaker 1: wind tunnels are are dead. Now we've got computational fluid dynamics,
Speaker 1: which is basically computers can figure all this out if
Speaker 1: you put a shape into you know, auto CAD and say, computer,
Speaker 1: figure out what you know will happen if I try
Speaker 1: to fly this under these conditions, It'll tell you um.
Speaker 1: And they people have said, well, you know, it takes
Speaker 1: a lot of work and a lot of money to
Speaker 1: run and build and use wind tunnels. UM. So I
Speaker 1: think they're probably going away people who work in wind
Speaker 1: tunnels saying no, to not do away with the wind tunnels.
Speaker 1: We need them still because yes, computation UM helps a
Speaker 1: lot with the early work, but when you finally have
Speaker 1: something that you need to prove, you really kind of
Speaker 1: want to see it in real life to make sure. Yeah,
Speaker 1: you want to see that smoke yourself. UM. And you
Speaker 1: know computer simulations can't simulate green smoke very well. You've
Speaker 1: got to see that in real life. So they they're
Speaker 1: saying that this is complementary technology and that they really
Speaker 1: we need to keep our wind tunnels around because we
Speaker 1: still need them. Yeah. And I think we'd also be
Speaker 1: remiss if we didn't say it's not just um vehicles
Speaker 1: and seeing how like a space shuttle or a car
Speaker 1: or a plane or a dune buggy might might run
Speaker 1: in the wind. Um. If you want to see how
Speaker 1: airflow if X like a computer U and components in
Speaker 1: a computer, you can yeah, good point, like how they come,
Speaker 1: how they cool computer chips. If you want to figure
Speaker 1: out the very best design for a wind turbine or
Speaker 1: wind farm, then you can use air tunnels. Um. There
Speaker 1: are lots of other different uses that you don't think
Speaker 1: about just on kind of everyday products. Sometimes. Yeah, there's
Speaker 1: a I have to say, there's a a Virginia Tech.
Speaker 1: There's an ann echoic, an echoic I believe, wind tunnel
Speaker 1: where they test wind turbines to see what kind of
Speaker 1: noise they're going to make. And they have so the
Speaker 1: walls are as far as the wind is concerned, it
Speaker 1: has four walls, but as far as sound is concerned,
Speaker 1: it has three because one of the walls is made
Speaker 1: of kevlar, so wind won't go through it, but sound
Speaker 1: will code right through it like it's not even there.
Speaker 1: So they can take accurate measurements of what's going to
Speaker 1: happen when the wind hits this turbine, what kind of
Speaker 1: sound is it going to make? And they're making the
Speaker 1: country folk who live among wor wind turbines much happier.
Speaker 1: That's awesome. Yeah, So that's it for wind tunnels, everybody.
Speaker 1: There's probably more to it, but it's far, far beyond
Speaker 1: chucks or my grasp. So again, hats off to all
Speaker 1: the aerodynamicists in all of their maths. Ah. If you
Speaker 1: want to know more about wind tunnels, go check stuff
Speaker 1: out on the internet. I hear there's a man with
Speaker 1: the page boy haircut who does a pretty mean demonstration.
Speaker 1: No no, no, that's just the printing press. Okay, I
Speaker 1: thought he was a factotum. He might be renaissance man. Um. Well,
Speaker 1: since I said renaissance man, everybody, it's time for listener mail.
Speaker 1: I'm gonna call this on Wetlands. And this is one
Speaker 1: from Brian from Queens and this is very cool. I
Speaker 1: didn't realize this. There was a a music venue in
Speaker 1: New York when I used to live up in New
Speaker 1: Jersey called Wetlands that I would go to, and I
Speaker 1: never knew that was kind of a cool story behind it,
Speaker 1: and now I do. So this is from Brian and
Speaker 1: he says, you know, the New York City area is
Speaker 1: surrounded by salt marshes and there are tons of or
Speaker 1: it says, protecting New York City's natural flood and pollution
Speaker 1: guards as you described them um in the nineties and
Speaker 1: throughout the eighties and nineties that the Wetlands Preserve. It
Speaker 1: was an activist nightclub named for the land that Lower
Speaker 1: Manhattan was built on. The club was on Hudson in Tribeca,
Speaker 1: very much Downtown Manhattan, which back in the early settlement
Speaker 1: by the Dutch was in subsequent subsequent takeover by the
Speaker 1: English was all Salt Marshes. Wetlands Preserve, colloquially referred to
Speaker 1: as the Wetlands was open from eighty nine to two
Speaker 1: thousand one. Dual purpose was to create an earth conscious,
Speaker 1: intimate nightclub that would nurture live music, integrated with a
Speaker 1: full time environmental and social justice activist center in the
Speaker 1: club's basement. Wait, what was the years that was open?
Speaker 1: Eighty nine to two thousand one? There is a hundred
Speaker 1: percent chance that Jewel played there. He doesn't list to it,
Speaker 1: but I bet she did. Okay, whoa he lists? He
Speaker 1: lists a few, but he also links to many more,
Speaker 1: and she's probably in there. I think I saw wean
Speaker 1: there if I'm not mistaken. But he said downstairs. Activist
Speaker 1: planned protests, made pamphlets, wrote letters to politicians and lobbies,
Speaker 1: generated boycotts and educated club patrons, while upstairs we hosted
Speaker 1: or they hosted some formative performances for legendary rock brands
Speaker 1: like Pearl Jam, Dave Matthews, Merein Five, Oasis, Widespread Forget,
Speaker 1: Jewel Fish, Rise Against Fishbone, Bikini Kill, Blind Melon, and
Speaker 1: Jewel Yes. The nightclub raised revenue for the Activism Center's
Speaker 1: effort efforts, and the intern Activism Center staff and volunteers
Speaker 1: educated nightclub patrons on environmental, social justice, and animal rights
Speaker 1: issues through posters, educational displays, literature, et cetera, and film screens.
Speaker 1: The New York based Wetlands Activism Collective continues. The club
Speaker 1: is shut down, but they continue it's environmental, social and
Speaker 1: political activism to this day. And that is from Brian Stolary. Nice, Ran,
Speaker 1: that's pretty great. I never knew that. I think it
Speaker 1: went to a couple of shows at Wetlands. Oh you did,
Speaker 1: and I never knew that there was something else going
Speaker 1: on there, and I kind of had forgotten about it.
Speaker 1: I wonder if when you showed through, like the Cops
Speaker 1: Cop Narc that was Brian. You said, Yeah, Brian Stolary,
Speaker 1: that's pretty cool. Thanks for filling in the blanks for
Speaker 1: us there Brian um and if you want to be
Speaker 1: like Brian and filling some blanks for us, you can
Speaker 1: send us an email send it off to Stuff podcast
Speaker 1: at iHeart radio dot com. Stuff you Should Know is
Speaker 1: a production of iHeart Radio's How Stuff Works. For more
Speaker 1: podcasts for my heart Radio is at the iHeart Radio app,
Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.