October 13, 2020 • 44 mins
Without wind tunnels we may not have airplanes right now. Early aviationists built them to puzzle out how to get and stay airborne. But wind tunnels are used for so much more than flight – from microchips to wind turbines. Enjoy this breezy episode.
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Episode Transcript
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Speaker 1 (00:01):
Welcome to Stuff You Should Know, a production of five
Heart Radios How Stuff Works. Hey, and welcome to the podcast.
I'm Josh Clark, there's Charles W. Bryant, and there's Jerry
Woosh Roland over there is just getting worse and worse.
(00:22):
This is Stuff You Should Know podcast wind Tunnel a
dish m Aren't you glad we're not in the same
room so that you couldn't smell my breath When I went, yeah,
my daughter's gotten a bad habit of doing that, and
she thinks it's funny. I'm like, it's really not of
what of like breathing and someone's nose on purpose, like
(00:46):
right in your face, and like no one, no one
likes that. Yeah, she's she's just entered the age of
what five to where that's something people do. Yeah, not
not funny. Ever, I'll tell you what. These masks that
we're all wearing, this is a real reckoning with your breath.
THO wouldn't it? Oh my god, it's funny. It's like
a it's like an hour by our slide into despair.
(01:11):
You're like, I don't remember eating garlics. Yeah, it's like
in the morning is like, oh man, this is great,
and I love this mask. And later in the day
you're you need that toothbrush. Yes, it's true. They say
you can't smell your own breath and they are wrong.
And I'm brushing my teeth now more than other because
I'm scared to go to the dentist. Yeah. Same here.
I'm also flossing like a mad person too. You're flossing
(01:31):
right now, I can, I can hear it. Wow, that
was the most pc thing I've ever said, is what
I'm flossing like a mad person, not a madman. And technically,
I guess not. I would have said like a mentally
ill health person. Yeah, I think that's even bad. Who
knows these days, right, that's right. Let's talk about wind tunnels. Okay,
(01:53):
so we're talking wind tunnels. Um, and I had no
idea how interesting wind to thos were. I had an
inkling that they were going to that there was like
more to wind tunnels than people realize, which is absolutely true. Um,
but they're they're pretty, they're deep cut. Yeah, I mean
there was way there's way more to them, and you
can do way more with them and learn way more
(02:14):
from them than I thought because my experience with wind tunnels.
Like most people is seeing the cool TV commercial with
the with the like green smoke flying over the car
to demonstrate how aerodynamic it is. And to be sure,
that is a very big part of what they use
wind tunnels for. Yeah. Yeah, and Chuck, you know, you
(02:35):
and I were in a commercial in a wind tunnel.
I thought you might bring this up. That was a
wind tunnel. Technically that that um indoor skydiving thing is
a type of wind tunnel. It's a vertical wind tunnel. Yeah,
if you guys haven't seen that. It's been a while
since we promoted these things. We used to do these
little shorts. Um no, this was different. Well no, but
these were based on the shorts. Yeah. Yeah, we did
(02:57):
these little shorts that we called interstitials. Did a lot
of them, and to me, it's like the best video
work we've ever done as a team. Um, I love
don't be done. But that was just you. Um well,
it was great. It was you in the room and
it was this chair and you sort of played a character. Yes,
go on, And some people have problems with the character
(03:18):
because I thought you were making fun of a certain
kind of person. Sure, that wasn't true. It was all
very kind hearted and just funny. That was really great,
Thank you. Sure. Uh and that chair still here in
the office, right, Yes it is, and I believe my
outfit still is. I'm waiting for the Smithsonian calm. So. Yeah.
We did this um TV commercial for Toyota that was
(03:39):
very much in the vein of those interstitials where we
were in just all over Atlanta, in various parts of
Atlanta doing funny things. That was l A. Remember well, no,
this was again talking about the original interstitiause I'm so confused.
Then when we went to l A, we did the
same thing. We replicated that style in Los Angeles and
long the upshot of this all is we end up
(04:00):
in a indoor uh skydiving facility having a conversation like
you know, a normal conversation or trying to That was
the gig, the gig. That was the gag. That was
the bit. Yeah, and you get slung against the side
of it at the end, which is kind of the
funniest part. Yeah, it really really was. It was supposed
to be an outtake and they made it an intake.
(04:22):
Those things were very difficult to uh if you've never
done one before. There, I mean, it was fun and
kind of cool, but it's not easy. You don't just
go in there and be like, hey, I'm floating. No,
it's really really hard actually, yeah, like you're working every
muscle in your body. It's kind of like water skiing
looks fun too. Yeah you were good at it. I
was not very good. I was okay, but it was
(04:43):
it was tough. Yeah. So, um, that was what would
be technically called a vertical wind tunnel, right, And they
actually used those two to research spin. Um, Like, when
something goes in, uh, like a tail spin, like a
helicopter goes in a tailspin, they would use a vertical
wind tunnel to test for that kind of thing. Right.
(05:05):
But the wind tunnels we kind of more think of
are the horizontal tubes where you see a car or
something like that having the cool smoke blown over it
for a commercial. But they're very useful. Um, and this
is something I didn't really know I kind of I
kind of just thought they were all these big giant
things that you would put an actual car in. Most
wind tunnels are these little desktop models that you use
(05:26):
in a science lab that have a scale model that
you're using instead of the actual thing, right, which which means, yeah,
that you're using a smaller version, but that is precisely
scaled down. It looks the right size, doesn't quit. I'm
sure this plane will fly, this is close enough. But
what's neat about that is that they can scale this
(05:48):
thing down. They can subject it to, you know, the
same conditions as they would a full size model. But
then they can correct for the data for that whatever
with the numbers they're getting the output, they can correct
to scale it back upwards. Um, just using math. Because
if there's one thing that goes hand in hand with
wind tunnels, it is math, friends, Because the whole point
(06:09):
of wind tunnels is to study aerodynamics, which is the
flow of air or gas is over an object. Um
And in this case it's a stationary object and the
wind is moving. But what they're really doing is simulating
that object moving out there in the real world into wind.
And I mean, that's a wind tunnel. And when you
put it like that, it sounds very simple. They are
(06:29):
not simple at all. There's really nothing about wind tunnels
that's simple, from their construction, to their cost, to what
they're used for, to all of the different variables and
conditions that they can test for there they grew step
in step, hand in hand with the aviation industry, Like
we probably wouldn't have an aviation industry right now without
(06:49):
wind tunnels. Um and that should kind of give you
an idea of how complex the stuff that people are
doing in wind tunnels is, or the data they're extracting
from these wind tunnels tests. It's not just like, look
that cool green smoke bending over the car. That's for
for yokels like you and I watching ads while you know,
(07:12):
in between golf, you know, like you're watching golf and
the ad comes on my brain. Is the best part
of golf, The ads I've actually kind of gotten. Are
you watching golf now? Yeah? Kind of here there. It's
not something I seek out. But and it's not for
the golf. I could care less about the golf. It's
the it's the views, it's the shots. The golf courses
(07:33):
are just they have the most amazing backdrops and it's
just so tranquil and calm. It's really something. Yeah, you know,
I live right down the street from the legendary East
Lake Country Club in Atlanta, Bobby Jones Course, and been
to one day of that one tournament. That's the only
time I've actually been to a professional golf tournament and
(07:55):
you know, I stood there twelve feet from Tiger Woods
and the tea box is pretty pretty neat. Wow, like
just to see because I played golf a lot growing
up and it's a hard sport and to see someone
do it uher perfectly right in front of your face
with that much power, was it was. It was really impressive.
You know what, what would really help Tiger Woods swing
(08:17):
if they put him in a wind tunnel, put some
green smoke in the wind and watch them swing. They
could tell him how to do it better. You want
smoke him smoke that's right, that's right. Shout out to
our Guard Detroit crew from the day. Al Right, So
if you want to go back in time and talk
about human flight, you're gonna look at things like Da
(08:37):
Vinci's ornithopter and kind of a lot of early stabs
at flying were humans looking at birds and thinking, well,
if we're gonna fly, we're gonna have to learn how
to flap wings really fast. And it made sense. I
guess if you're looking at birds, they're the only thing
(08:59):
flying around. Uh, it would make sense that that's where
they would go. But they knew early on, regardless of
the flapping, that they needed to understand wind and how
wind worked with wings. And so they started going to
these little hills and mountains and they started going to
caves that had you know, they were looking for some
(09:20):
sort of predictable, constant wind so they could do some
early testing. And they realized, you just can't do it
with mother nature. You can't get a consistent wind, not
enough to get real data out of it and do
that math that we need so so drastically to make
this possible. Right so, and and initially we got that
assist from birds and that we knew wings had to
(09:42):
be involved. That the whole flapping thing really kind of
threw things off for a while. But because we knew
that there had to be wings, we knew that there
had to probably be some ideal or optimum shape of wings.
And that's really where wind tunnels first got their start,
wasn't testing different shape of wings or air foils. And
there was a guy back in seventeen forty six named
(10:04):
Benjamin Robbins who created a wiry arm um, which is
basically like a It was a centrifuge basically is what
he created. He had a hard time picturing this, and
there's only there's this one very rudimentary sketch that made
it even more confusing. Okay, so just just imagine you
(10:24):
have like a pole coming out of the ground vertically
and you have an arm attached to that pole, and
the pole can spin around in a circle like a centrifuge,
like one of those G force testers that they have
at and like, um, like astronaut training, you know what
I'm saying. Yeah, yeah, yeah, that thing. This is what
that guy invented. But it was like with wood and
(10:47):
in the dirt. It wasn't and it didn't go that fast.
But you could have fixed a like a wing type
that you were testing to see if it worked well
to the end of it and push it through the air.
And it didn't really help this guy figure out what
wings style or size was the best. What it helped
him figure out is that it doesn't have that much
(11:07):
to do with anything with flapping. We don't need to
be wasting our time inventing machines that that flap their wings,
because that's not it. It's all about this thing called
lift and drag and the proportion between those two. And
if you can figure out how to get more lift
and decreased drag. Then you can you can really make
some you can fly basically, And this was the very
(11:30):
first inklings of that that Benjamin Robbins came came up with. Yeah,
and what I saw was that Robbin's really kind of
pinpointed drag, like the shape is super important. And then
after him, Sir George Cayley had his own whirling arm
and he's the one that really figured out lift was
a key. After they realized the shape of the thing
matters the um more than the shape, like the size
(11:53):
of it matters. Size does matter, especially when you're flying,
especially when you're flying, and uh that if you could
just get a quick enough takeoff, you don't need to
flap at all. All you need is a lot of
speed at first, which they could have also gotten frankly
by if they would have kept looking at birds and
realized they eventually stopped flapping, they might have realized, oh,
(12:16):
you actually don't need to flap the whole time. You
can glide if you've got enough speed, right and and well,
actually a lot of the early flying machines were gliders.
It was one of the the Wright brothers were not
the first people to UM engage in in human flight.
There is a monk named Elmer of Malmsberry who has
the first recorded human flight back in ten fifty c
(12:38):
E not b C and um he he You know,
that was almost a thousand years before the Right Brothers UM.
But the Right Brothers are credited with with UM the
like an engine powered flight human flight. Right, So they
they were dabbling in what's what Kaylee and Robbin's well,
(12:58):
Kaylee especially figured out that you need thrust and there's
just nothing around that's light enough to produce enough thrust.
So Kaylee actually gave up and went and joined parliament
for a while before he finally created a flying machine.
Fifty years before the Right Brothers. He made his UM.
He made his coach driver test pilot it, and the
coach driver was so scared even though the flight was
(13:20):
successful that when he landed he was like, I quit,
I quit. I'm not. I don't work for you anymore. Yeah,
but George Kayley's very much overlooked figure in the history
of flight. He apparently figured out the general shape um
of a modern airliner back in Yeah. Alright, I say
we take a break, we'll come back and talk about
(13:42):
the first wind tunnel right after this. Alright, so Kaylee
(14:10):
has these whirling arms going terrible name, but it worked out. Uh.
Then enter a man named Frank h Win him. He
was another Englishman and he was in the Aeronautical Society
of Great Britain, and he said, guys, we need or
excuse me, gentlemen, we need a wind tunnel, and we
need it bad. And so in eighteen seventy one he
(14:32):
had the very first wind tunnel. Was twelve ft long,
about eighteen inches square, with a forty mile wind, which
is pretty good. It was. It consisted of your daughter going,
oh god, stinky has went dunne her breath. Isn't that
stinky yet? Kids don't really start to stink until later,
I think, yeah, until later. But the winds were powered
(14:56):
by a steam fan at the end of the tunnel,
and it worked pretty well. He was able to get
that leading edge of the airfoil and move it up
and down and change his angle angle of attack and
kind of see what shaped, uh and what angles worked
best with to get the best lift. But it was
still sort of choppy, and it was rough around the edges.
(15:18):
And if you really want to make this you know,
if you want to fly safely, you got to have
a really really really consistent, very smooth wind to work
with to get that data. And they still didn't have
one at this point. Now they still didn't, but they
were advancing by leaps and bounds here that people were
building their own wind tunnels. Because up to that point,
(15:39):
if you had in a design for an airfoil, for
like a wing size or shape, you had to build
it and then go take it out into nature and
test it and hope for the best, and it was
really expensive, really time time consuming. With your own wind
wind tunnel, you could make a model of the shape
and test it out yourself and then see this is
actually worth pursuing, or this as junk, and that's it.
(16:01):
That's what our dear beloved heroes, the Right brothers did
in Ohio outside of Dayton, Lorville and Wilbur Wright Um
built their own wind tunnel. These guys were just like tinkerers.
They owned a bike shop, but they were so fascinating
were following these developments in early flight that they just
kind of got into it themselves and they built themselves
(16:21):
a wind tunnel. They had like two different or two
hundred different types of wings. I believe that they messed
with selected the thirty best ones that they had developed
in their wind wind tunnel of their own construction and
design um And apparently I saw somewhere that by nine one,
after their wind tunnel tests, the Right Brothers, a couple
(16:41):
of bicycle repairment in Dayton, had the world's um most
accurate data scientific data on on flying and wings in
the world. And they'd come up with it entirely by themselves. Yeah,
and here's the thing with these wind tunnels, especially early
on in kind of still, it's not like they could
(17:02):
use that wind tunnel and come out with a surefire
product using math and uh and testing different designs and
shapes and tilts and angles. But it was such a
time saver and broken bone saver that you didn't just say,
all right, well, I think this might work. Let's go
and push our cousin off of a cliff or our
coach driver or whatever and see if it works. They
(17:24):
still had their failures, all of them did, But I
mean it would have taken I mean, god knows how
many more years if they didn't, like at least start
from a point of likely success thanks to wind tunnels.
But I mean, like, look at it. They went from
they finished their wind tunnel tests in nineteen o one,
they had their first powered flight in en three. Yeah,
(17:46):
I mean that's so it's amazing two years and it
definitely did accelerate it too. And so you can see
from the outset that that aviation and wind tunnels just
developed together, and wind tunnels developed aviation um. But the
first wind tunnels, like you said, they had a really
big problem, and that was the air that they produced.
(18:06):
The stream of wind was very choppy, very turbulent, and
your data was not necessarily reliable. It wasn't too terribly
much better than say, going out into mother Nature and
subjecting you know, the same model to those winds um
And that's a big problem. So one of the first
things that they figured out how to do was to
(18:28):
make the wind smoother so that you could get a reliable, smooth,
steady wind um in your wind tunnel whenever you wanted
to use it. Yeah, and that's where we come to
the modern tunnel, very very smooth airflow. And they have
five basic sections of and they're you know, they're all different,
but they have five basic sections. In a modern tunnel
(18:51):
that's the settling chamber, the contraction cone, the test section,
the diffuser, and the drive section. So we start out
with this swirling air and it's a big choppy mess
and it enters the tunnel and we'll talk about how
in a second, because it's kind of cool, little counterintuitive,
but it makes a lot of sense. Um it goes
into the settling chamber, which does exactly what you think.
(19:13):
It settles that air, straightens it out. They might have
these little honeycomb holes or a screen or these panels,
and that's just sort of the initial thing to sort
of get it nice and smooth and moving in the
same uniform direction. Yeah, and then it goes down. They
step it down through that contraction cone, and that just
I mean, it's like anything else. If you make the
(19:35):
the tube smaller, it's going to increase that velocity of
air flow. And that's where it gets to the test section,
which is whatever. And the test section depends on what
you're testing. If it's a desktop thing, the test section
might be twelve inches long and you might have a
tiny little model of an airplane wing in there, and
(19:55):
that's where the actual thing you're testing is and where
all the sensors are record all the data because you know,
you've got your visual that you've got these windows so
you can shoot TV commercials and you can look at
the thing. But there's also all manner of sensors to
pick up on all manner of UH data and observations. Yeah,
I think that's really cool that they still you know,
(20:16):
when they operate wind tunnels, they still watch through the
window because there's a lot to be gained visually from
from just human beings watching this stuff, and so you
want to you want to watch it right, Yeah, for sure,
especially when they got the green smoke thing turned on.
So after it goes through the um, the test section
(20:36):
enters a diffuser UM which kind of it slows things,
slows things down UM and maybe just exits the whole thing.
It's kind of the opposite of the contractor it just
opens back up right exactly. So there's UM, there's there
as far as breaking. There's a lot of different kinds
of wind tunnels, as we'll see, but there's really kind
(20:58):
of two categories too, broad categories. You've got open and
closed circuit, and an open circuit is where you have
wind going in on one end, going through the diffuser
and the honeycomb in the test section and then coming
out the other end blowing into the room and another
with the closed circuit. It's just basically an oval and
so when the wind is generated, it goes through the
(21:20):
it goes through the test section out the back, but
then bends around an oval track and then comes back
around again and through the contraction coning into the test
section again and again, and can just keep going rather
than just blowing out the other side. Yeah, and here's
the part that I said wasn't intuitive, but it's really
kind of neat when you think about it. The drive
section is where this fan is, and this is what
(21:41):
it's just generating that air flow. And I always just
thought a wind tunnel was a fan pointing at the thing.
They're actually behind the thing, because you don't want to
push air onto something, you want air being pulled over something.
And it it just makes total sense, but you ever
really thought about it, You just I always just pictured
(22:02):
a big fan blowing at a car, but the fan
would actually be behind the car and it's probably looping
around and smoothing out this entire way and then being
gently pulled over the car exactly. And in just the
same way that the fastest way to cool off, say
like a server room that you don't have good cooling on,
you just throw a box fan the opposite way. So
(22:24):
the boxman is blowing out into the regular room, but
at the same time it's sucking the air, the hot
air out of the out of the server room, and
cool air is rushing into a place that hot air.
So you're creating like an air flow that's much less turbulent.
When the fan sucks the air out, it's much smoother
than when it blows it in, which creates a lot
(22:46):
more turbulence. And that was the big problem that was
facing like the Right Brothers and some of those other
early wind tunnel creators, is they their fans were blowing
on the front of their models rather than having the
fan behind it sucking the air over the models. Right.
So these little models they're kept in place, sometimes around wire,
(23:06):
sometimes around these middle poles. Uh sometimes I think they
really super high tech ones use um super strong magnets
to actually hold them in place, which is pretty cool.
And then again you've got all these sensors all over
the place attached to the model measuring I mean, we'll
see it gets really really deep. But just at the
(23:27):
outset you can measure like wind velocity and air pressure
and temperature, and if you're talking about airplanes, roll and
yaw and drag and lift, and I mean, you can
kind of do anything you want in there. And if
you have, like if you're testing an airplane or a
scale model of the airplane you're gonna build, it's on
(23:47):
something called the sting, which is a pole basically that
goes into the airplanes bottom. But but then inside the airplane,
the airplane is not attached to the pole. It's attached
to something called a balance. And it's like all those
sensors you just mentioned all in one instrument, like a
cylinder tube, and as the airplane moves and pitches and
(24:08):
yaws and rolls and and gallops and all that stuff,
not gallops, So I made that part up. UM, it's
it's acting on those sensors and the motion, the mechanical
motion on those sensors is translated into an electrical impulse
and that travels down the stinger into the computers which
are picking up all of this data in real time
(24:29):
and UM logging it and creating new new versions of
the UH the model based on that stuff. It's pretty amazing.
What's even more amazing that makes sense that that exists today,
That's existed since like the forties or the fifties, and
in much more primitive form, but essentially the same thing
that we use today, the same kind of balance what
(24:50):
has been around for decades. Wasn't there a Simpsons joke
about y'all control? Yes, yeah, when they had one of
those like backyard pockets now with yaw control and didn't
like buzz Aldrin or something, say like, wow, look at
that y'all control. I think so that was good stuff. Uh.
Some other things that they measure, which you might not
(25:13):
really think about existing is viscosity and compressibility, or the
tackiness or the bounciness of the air itself. So when
you're thinking about air blowing over a car driving down
the road, you don't think of that air is like
being sticky necessarily. But when that air is moving over
the hood of that car, in the top of that
(25:33):
car or the plane or whatever it is, Uh, those
little molecules are gonna hit the surface and just very
very briefly, they're going to cling to that surface, and
that even for that brief brief amount of time. It's
gonna create a little boundary layer of air next to
the thing that you're trying to measure air flow over. Yeah,
which is, like I said, a very big deal. And
and yeah, an individual air molecule is going to stick
(25:56):
for a nano second, just some ridiculously short amount of time.
But there's so many air molecules that they essentially just
replace each other as fast as they can move. And yes,
they create this this this boundary layer. And as far
as aerodynamics is concerned, your your say, your car blow
go like driving through this wind that's that's sticking to
(26:17):
it um now has a different shape. That boundary layer
creates a different shape or extends it outward beyond the
actual physical shape of the car. And so, yes, very
much so. And then so so when you're trying to
test like how fast the car is going to go,
how many miles per gallon it's going to get that
kind of stuff. That boundary layer makes a tremendous amount
(26:41):
of difference because it changes physically changes the shape of
this this thing when it's out there traveling at high speeds.
So one of the great benefits of an air tunnel
is you can test, like, what boundary layer is produced
by this particular shape of this car under this condition.
You know, if it's um humidity, but you know forty
(27:01):
degrees ferrent height. Uh, and they're traveling at eighty miles
an hour, what kind of boundary layers produced? Okay, well
what about seventy five an hour at the sixty percent humidity.
You can just change all these variables, and the wind
tunnel allows you to simulate it in in in Basically, UM,
get all this data in real time. UM. Just lickety
(27:22):
split basically. Although one other thing, I just want to
say this, we're making it sound like this is fast.
This is actually, and has been, especially until the age
of computers, very arduous work. Because if you wanted to
change one variable, if you said, well, this headlight is
actually causing way too much drag, you would have to
switch that headlight out with your next model and run
the same tests over and over and over again with
(27:42):
the different different um conditions and log all that data.
So it was really arduous before computers, and you kind
of get the idea that aerodynamics as a field of
study is really given over to computation. Like there has
been a huge savior for that field and helped it
along and saved a lot of people a lot of time. Yeah,
and you mentioned things like humidity and temperature um. There
(28:07):
are all different kinds of wind tunnels, and they can
be very specific as to what they want to test
or very broad, but they're they're all able to do
things like that. You can dial in a temperature, you
can dial in um atmospheric pressure if you want to
see what something' is like on Mars, which they have
to do if you want, like the Mars Rover to
be successful. They can. They can ice up a plane
(28:29):
wing just by introducing refrigerated air and spraying a mist
of water that freezes and lands on the wing, and
you can simulate all these different things humidity and temperature,
And it's just amazing that that they thought to to introduce.
You know, at first they started out probably just looking
at aerodynamics of flow over a thing, but as they
(28:52):
got more and more specific with their needs, they just said,
you know that we can design these tunnels to kind
of do anything we want to do, like recreate any
and vironment you can think of. Basically, Yeah, it's true,
and I mean like as as we started to build
planes that go faster and faster. We started building tunnels
that simulated that really high speed travel, and so we
(29:12):
have hypersonic and supersonic um wind tunnels that don't use
fans at all, but they use like bursts of compressed
air that blow right onto the model. Those do blow
at the thing instead of sucking behind it. Right. Um.
But it's it's a huge release of of air that
is traveling so fast it simulates you know, like a
(29:32):
jet flying through you know, hundreds of you know, millions
of miles an hour probably yeah, or hey, what's it
like for a rocket human capsule too, uh to come
back into Earth's atmosphere at the and and not burn
up like they can simulate those temperatures. Yeah, there's one
(29:53):
in I think North Carolina. No University of Texas at
Arlington has something that can simulate that goes up Torees Ferren.
It's crazy, man, it is. It's a wind tunnel for
all in times of purpose. It's a wind tunnel. But
they have built these things so that they can simulate
basically any any climate. And you know, we talked about smoke,
and it's always fun in those TV commercials to see
(30:15):
the smoke blowing over the thing. And it's a nice
visual to sell cars that look super aerodynamic in our
super aerodynamic. But that visible flow isn't just you know,
for the stoners in the lab department, like late at
night to play around with, although they probably do that,
but they flow visualization is a real technique. Um, you
(30:37):
might just have colored smoke, you might have liquid, like
a mist of liquid. You might have they use this
colored oil sometimes that uh you can see like the
wind pushing the oil along the surface of whatever model
you're using, and then they've got these high speed cameras
capturing all of it. And again it's just, um, it's
another variable they can actually look at rather than just
(30:59):
using numbers and data. Yeah, I saw one, um one
was taking photographs of like two thousand frames per second.
That speed it was, but it was they were testing
like a rocket or something or model of it. Should
we take a break, Yeah, let's all right. We'll be
right back with more on wind tunnels right after this.
(31:43):
So Chuck, I was like a lot of this really
breaks my brain. It's one of those things we're like,
oh yeah, I totally get this on the surface. Let
me scratch a little deeper. I don't understand this at all.
And the reason why is because you know, aerodynamics requires
a lot of math and formula and all sorts of
calculations that I'm not contrated that I'm not currently capable
(32:04):
of doing that. But one of the things that I
tried to shake down was when you do a scale
model of something, do you have to scale down the conditions?
And it turns out I wasn't the first one to
think about this. Other people have, including people who work
in wind tunnels, and apparently they do not do that.
(32:25):
They will say, subjected to the same wind speed as
they would like the full size one, but then they
go back and use math to adjust um these that
all the different variables and again, you know, we talked
about pitch and y'all, role um, drag lift, all sorts
of stuff. I'm sure quite a few things and variables
(32:45):
that you and I haven't even come up with um
or run across during our research. But in each one
of these interacts with each other thing, right, So it's
like one of those things where you know you have
a eleven possible hoppings for a pizza and that creates
twelve million potential combinations. It's a brain breaking amount of
(33:06):
math involved exactly. So that's what they're doing. To scale
it down and scale it up. They can say, oh, well,
it produced this data. If we run it through these
these you know, formula um like, we can show that actually,
like it will have this effect in the in the
real world. They're using that level of math. Anybody who
(33:27):
can do that with math, I admire them deeply. If
you're listening out there and you can do stuff like
that with math, my hat is off to you because
I will never be able to do that, and I
admire you. Yeah, And you know what, we've taken some
heat for kind of beating up on math a little
bit is like boring because we were English and journalism
guys and history guys. But uh, I've really come to
(33:50):
appreciate math and doing this show. I'm no better at
it and don't care to be, but I appreciate the
You know, math is the one thing that doesn't care
about what you think about it. It doesn't care about opinions,
and there's no interpretation or nuance. It's just it's just math.
And like what makes like to look at these to
(34:11):
look at a math equation that would take a model
of an airplane and a tiny little thing and a
tiny wind tunnel and then say, well, now we just
scale it up to this, and this is how you
do it right, just multiplied by time. It makes me
so nervous, But a real mathematician would be like, this
is the last thing you should ever be nervous about,
because it's it's just math. It's just right there. Well,
it's just and they probably the idea of them of
(34:34):
doing public speaking would probably scare the Jesus. And the
thing is exactly like, different things attract different people, and
that's great because that makes the world a lot more
rich and complex that you have all these different people.
If everyone was in the math, it would be a
pretty boring place, or if everybody hated math would be
a pretty boring place to Like, you need all different kinds,
different strokes for different folks. Makes the world go round,
(34:56):
I think, is the rest of them. All. Right, Let's
talk about some of these wind as in the world,
because they're amazing. NASA has one at Ames Research Center
in San Jose or near San Jose, biggest in the world,
biggest one hundred and eighty feet tall, dude four hundred
feet long, and the test section on this thing is
eight ft tall and a hundred twenty ft wide, so
(35:17):
you can put a full size jet plane in that thing. Yeah.
I saw that. I was like, well, what kind and
they said seven thirty seven. Yeah, that's pretty good that kind, buddy,
pretty pretty good size. So yeah, that's a I don't
know if they call it this, but I hear here
henceforth call it the Big Man with jam. Yeah. It
uses six four story high fans, each of which is
(35:41):
powered by six two thousand, five hundred horsepower motors. Six
fans each as tall as a four story building. That man,
that's amazing. A hundred and fifteen mile in our winds
is where it tops out, yeah, which is pretty great.
Um that there's also a lot apparently. I was reading one,
(36:02):
um uh, some like blog posts I think on like
a Formula one site, and they were talking about how
like every single company, every single racing team has in
its facility of full size wind one like it can
hold a full size Formula one car the cost of
like six million dollars or whatever. But they are um
like cutting edge as far as um aerodynamic study is concerned. UM.
(36:28):
And the reason why is because like if you can
shave a second off of somebody's time just by reconfigure
the engineers reconfiguring the shape of a fin or a
tail or something like that. That's that you just it
just paid for itself basically because it may have just
one like the you know, good job there, Yeah, thank you.
(36:49):
So there are NASCAR's obviously obviously got a couple of
these things in North Carolina. The home of NASCAR Aerodin
wind Tunnel. UM that is in North Carolina, and it
tests full sized stock cars. There's no one called wind
shear there. Um. This is a closed circuit tunnel that
actually has a treadmill in it for cars. It's got
(37:11):
a built in rolling road. Yeah, saw that in a
few places, like BMW has one with the rolling road.
You know what's interesting to me too, is so we
saw that the aviation industry and UM and wind tunnels
kind of grew hand in hand. The auto industry didn't
really look up wind tunnels until about the fifties is
when they really started running their cars through those, and
(37:35):
they went, boy, these cars are not aerodynamic. Now look
at it. Look at that yaw control. Though. Yeah, I
love those old cars. Though I used my old Plymouth
Valiant that I used to have. Um. This is obviously
way before anyone ever thought of anything like anti lock breaks.
And one of the most fun things I would do
(37:55):
when I was driving with friends on an empty road
late at night was get up to about fifty miles
an hour and just slam on the brakes. It was
so much fun, man, it was great. You would just go.
You would slide about a hundred feet before finally coming
to arrest. That was a great impression of slamming on
the brakes too, by the way, it was good and
(38:16):
you know it. It was like we called it the
sled because it was just this big, heavy hunk of metal.
It's not like I was sliding all over the road.
I was just sliding very straight in a line. What's
the opposite of aerodynamic that Plymouth Valiant? There you go, um,
sluggish like a what sponge? Yeah, that's about right. So UM,
(38:39):
I think we should wrap this up on the future
of wind tunnels because people have been saying like, well,
wind tunnels are are dead. Now we've got computational fluid dynamics,
which is basically computers can figure all this out if
you put a shape into you know, auto CAD and say, computer,
figure out what you know will happen if I try
to fly this under these conditions, It'll tell you um.
(39:02):
And they people have said, well, you know, it takes
a lot of work and a lot of money to
run and build and use wind tunnels. UM. So I
think they're probably going away people who work in wind
tunnels saying no, to not do away with the wind tunnels.
We need them still because yes, computation UM helps a
lot with the early work, but when you finally have
(39:23):
something that you need to prove, you really kind of
want to see it in real life to make sure. Yeah,
you want to see that smoke yourself. UM. And you
know computer simulations can't simulate green smoke very well. You've
got to see that in real life. So they they're
saying that this is complementary technology and that they really
we need to keep our wind tunnels around because we
still need them. Yeah. And I think we'd also be
(39:46):
remiss if we didn't say it's not just um vehicles
and seeing how like a space shuttle or a car
or a plane or a dune buggy might might run
in the wind. Um. If you want to see how
airflow if X like a computer U and components in
a computer, you can yeah, good point, like how they come,
(40:06):
how they cool computer chips. If you want to figure
out the very best design for a wind turbine or
wind farm, then you can use air tunnels. Um. There
are lots of other different uses that you don't think
about just on kind of everyday products. Sometimes. Yeah, there's
a I have to say, there's a a Virginia Tech.
There's an ann echoic, an echoic I believe, wind tunnel
(40:27):
where they test wind turbines to see what kind of
noise they're going to make. And they have so the
walls are as far as the wind is concerned, it
has four walls, but as far as sound is concerned,
it has three because one of the walls is made
of kevlar, so wind won't go through it, but sound
will code right through it like it's not even there.
(40:47):
So they can take accurate measurements of what's going to
happen when the wind hits this turbine, what kind of
sound is it going to make? And they're making the
country folk who live among wor wind turbines much happier.
That's awesome. Yeah, So that's it for wind tunnels, everybody.
There's probably more to it, but it's far, far beyond
chucks or my grasp. So again, hats off to all
(41:10):
the aerodynamicists in all of their maths. Ah. If you
want to know more about wind tunnels, go check stuff
out on the internet. I hear there's a man with
the page boy haircut who does a pretty mean demonstration.
No no, no, that's just the printing press. Okay, I
thought he was a factotum. He might be renaissance man. Um. Well,
(41:30):
since I said renaissance man, everybody, it's time for listener mail.
I'm gonna call this on Wetlands. And this is one
from Brian from Queens and this is very cool. I
didn't realize this. There was a a music venue in
New York when I used to live up in New
Jersey called Wetlands that I would go to, and I
never knew that was kind of a cool story behind it,
(41:53):
and now I do. So this is from Brian and
he says, you know, the New York City area is
surrounded by salt marshes and there are tons of or
it says, protecting New York City's natural flood and pollution
guards as you described them um in the nineties and
throughout the eighties and nineties that the Wetlands Preserve. It
was an activist nightclub named for the land that Lower
(42:14):
Manhattan was built on. The club was on Hudson in Tribeca,
very much Downtown Manhattan, which back in the early settlement
by the Dutch was in subsequent subsequent takeover by the
English was all Salt Marshes. Wetlands Preserve, colloquially referred to
as the Wetlands was open from eighty nine to two
thousand one. Dual purpose was to create an earth conscious,
(42:35):
intimate nightclub that would nurture live music, integrated with a
full time environmental and social justice activist center in the
club's basement. Wait, what was the years that was open?
Eighty nine to two thousand one? There is a hundred
percent chance that Jewel played there. He doesn't list to it,
but I bet she did. Okay, whoa he lists? He
(42:57):
lists a few, but he also links to many more,
and she's probably in there. I think I saw wean
there if I'm not mistaken. But he said downstairs. Activist
planned protests, made pamphlets, wrote letters to politicians and lobbies,
generated boycotts and educated club patrons, while upstairs we hosted
or they hosted some formative performances for legendary rock brands
(43:17):
like Pearl Jam, Dave Matthews, Merein Five, Oasis, Widespread Forget,
Jewel Fish, Rise Against Fishbone, Bikini Kill, Blind Melon, and
Jewel Yes. The nightclub raised revenue for the Activism Center's
effort efforts, and the intern Activism Center staff and volunteers
educated nightclub patrons on environmental, social justice, and animal rights
(43:41):
issues through posters, educational displays, literature, et cetera, and film screens.
The New York based Wetlands Activism Collective continues. The club
is shut down, but they continue it's environmental, social and
political activism to this day. And that is from Brian Stolary. Nice, Ran,
that's pretty great. I never knew that. I think it
(44:01):
went to a couple of shows at Wetlands. Oh you did,
and I never knew that there was something else going
on there, and I kind of had forgotten about it.
I wonder if when you showed through, like the Cops
Cop Narc that was Brian. You said, Yeah, Brian Stolary,
that's pretty cool. Thanks for filling in the blanks for
(44:21):
us there Brian um and if you want to be
like Brian and filling some blanks for us, you can
send us an email send it off to Stuff podcast
at iHeart radio dot com. Stuff you Should Know is
a production of iHeart Radio's How Stuff Works. For more
podcasts for my heart Radio is at the iHeart Radio app,
Apple Podcasts, or wherever you listen to your favorite shows.
Welcome to Stuff You Should Know, a production of five
Heart Radios How Stuff Works. Hey, and welcome to the podcast.
I'm Josh Clark, there's Charles W. Bryant, and there's Jerry
Woosh Roland over there is just getting worse and worse.
(00:22):
This is Stuff You Should Know podcast wind Tunnel a
dish m Aren't you glad we're not in the same
room so that you couldn't smell my breath When I went, yeah,
my daughter's gotten a bad habit of doing that, and
she thinks it's funny. I'm like, it's really not of
what of like breathing and someone's nose on purpose, like
(00:46):
right in your face, and like no one, no one
likes that. Yeah, she's she's just entered the age of
what five to where that's something people do. Yeah, not
not funny. Ever, I'll tell you what. These masks that
we're all wearing, this is a real reckoning with your breath.
THO wouldn't it? Oh my god, it's funny. It's like
a it's like an hour by our slide into despair.
(01:11):
You're like, I don't remember eating garlics. Yeah, it's like
in the morning is like, oh man, this is great,
and I love this mask. And later in the day
you're you need that toothbrush. Yes, it's true. They say
you can't smell your own breath and they are wrong.
And I'm brushing my teeth now more than other because
I'm scared to go to the dentist. Yeah. Same here.
I'm also flossing like a mad person too. You're flossing
(01:31):
right now, I can, I can hear it. Wow, that
was the most pc thing I've ever said, is what
I'm flossing like a mad person, not a madman. And technically,
I guess not. I would have said like a mentally
ill health person. Yeah, I think that's even bad. Who
knows these days, right, that's right. Let's talk about wind tunnels. Okay,
(01:53):
so we're talking wind tunnels. Um, and I had no
idea how interesting wind to thos were. I had an
inkling that they were going to that there was like
more to wind tunnels than people realize, which is absolutely true. Um,
but they're they're pretty, they're deep cut. Yeah, I mean
there was way there's way more to them, and you
can do way more with them and learn way more
(02:14):
from them than I thought because my experience with wind tunnels.
Like most people is seeing the cool TV commercial with
the with the like green smoke flying over the car
to demonstrate how aerodynamic it is. And to be sure,
that is a very big part of what they use
wind tunnels for. Yeah. Yeah, and Chuck, you know, you
(02:35):
and I were in a commercial in a wind tunnel.
I thought you might bring this up. That was a
wind tunnel. Technically that that um indoor skydiving thing is
a type of wind tunnel. It's a vertical wind tunnel. Yeah,
if you guys haven't seen that. It's been a while
since we promoted these things. We used to do these
little shorts. Um no, this was different. Well no, but
these were based on the shorts. Yeah. Yeah, we did
(02:57):
these little shorts that we called interstitials. Did a lot
of them, and to me, it's like the best video
work we've ever done as a team. Um, I love
don't be done. But that was just you. Um well,
it was great. It was you in the room and
it was this chair and you sort of played a character. Yes,
go on, And some people have problems with the character
(03:18):
because I thought you were making fun of a certain
kind of person. Sure, that wasn't true. It was all
very kind hearted and just funny. That was really great,
Thank you. Sure. Uh and that chair still here in
the office, right, Yes it is, and I believe my
outfit still is. I'm waiting for the Smithsonian calm. So. Yeah.
We did this um TV commercial for Toyota that was
(03:39):
very much in the vein of those interstitials where we
were in just all over Atlanta, in various parts of
Atlanta doing funny things. That was l A. Remember well, no,
this was again talking about the original interstitiause I'm so confused.
Then when we went to l A, we did the
same thing. We replicated that style in Los Angeles and
long the upshot of this all is we end up
(04:00):
in a indoor uh skydiving facility having a conversation like
you know, a normal conversation or trying to That was
the gig, the gig. That was the gag. That was
the bit. Yeah, and you get slung against the side
of it at the end, which is kind of the
funniest part. Yeah, it really really was. It was supposed
to be an outtake and they made it an intake.
(04:22):
Those things were very difficult to uh if you've never
done one before. There, I mean, it was fun and
kind of cool, but it's not easy. You don't just
go in there and be like, hey, I'm floating. No,
it's really really hard actually, yeah, like you're working every
muscle in your body. It's kind of like water skiing
looks fun too. Yeah you were good at it. I
was not very good. I was okay, but it was
(04:43):
it was tough. Yeah. So, um, that was what would
be technically called a vertical wind tunnel, right, And they
actually used those two to research spin. Um, Like, when
something goes in, uh, like a tail spin, like a
helicopter goes in a tailspin, they would use a vertical
wind tunnel to test for that kind of thing. Right.
(05:05):
But the wind tunnels we kind of more think of
are the horizontal tubes where you see a car or
something like that having the cool smoke blown over it
for a commercial. But they're very useful. Um, and this
is something I didn't really know I kind of I
kind of just thought they were all these big giant
things that you would put an actual car in. Most
wind tunnels are these little desktop models that you use
(05:26):
in a science lab that have a scale model that
you're using instead of the actual thing, right, which which means, yeah,
that you're using a smaller version, but that is precisely
scaled down. It looks the right size, doesn't quit. I'm
sure this plane will fly, this is close enough. But
what's neat about that is that they can scale this
(05:48):
thing down. They can subject it to, you know, the
same conditions as they would a full size model. But
then they can correct for the data for that whatever
with the numbers they're getting the output, they can correct
to scale it back upwards. Um, just using math. Because
if there's one thing that goes hand in hand with
wind tunnels, it is math, friends, Because the whole point
(06:09):
of wind tunnels is to study aerodynamics, which is the
flow of air or gas is over an object. Um
And in this case it's a stationary object and the
wind is moving. But what they're really doing is simulating
that object moving out there in the real world into wind.
And I mean, that's a wind tunnel. And when you
put it like that, it sounds very simple. They are
(06:29):
not simple at all. There's really nothing about wind tunnels
that's simple, from their construction, to their cost, to what
they're used for, to all of the different variables and
conditions that they can test for there they grew step
in step, hand in hand with the aviation industry, Like
we probably wouldn't have an aviation industry right now without
(06:49):
wind tunnels. Um and that should kind of give you
an idea of how complex the stuff that people are
doing in wind tunnels is, or the data they're extracting
from these wind tunnels tests. It's not just like, look
that cool green smoke bending over the car. That's for
for yokels like you and I watching ads while you know,
(07:12):
in between golf, you know, like you're watching golf and
the ad comes on my brain. Is the best part
of golf, The ads I've actually kind of gotten. Are
you watching golf now? Yeah? Kind of here there. It's
not something I seek out. But and it's not for
the golf. I could care less about the golf. It's
the it's the views, it's the shots. The golf courses
(07:33):
are just they have the most amazing backdrops and it's
just so tranquil and calm. It's really something. Yeah, you know,
I live right down the street from the legendary East
Lake Country Club in Atlanta, Bobby Jones Course, and been
to one day of that one tournament. That's the only
time I've actually been to a professional golf tournament and
(07:55):
you know, I stood there twelve feet from Tiger Woods
and the tea box is pretty pretty neat. Wow, like
just to see because I played golf a lot growing
up and it's a hard sport and to see someone
do it uher perfectly right in front of your face
with that much power, was it was. It was really impressive.
You know what, what would really help Tiger Woods swing
(08:17):
if they put him in a wind tunnel, put some
green smoke in the wind and watch them swing. They
could tell him how to do it better. You want
smoke him smoke that's right, that's right. Shout out to
our Guard Detroit crew from the day. Al Right, So
if you want to go back in time and talk
about human flight, you're gonna look at things like Da
(08:37):
Vinci's ornithopter and kind of a lot of early stabs
at flying were humans looking at birds and thinking, well,
if we're gonna fly, we're gonna have to learn how
to flap wings really fast. And it made sense. I
guess if you're looking at birds, they're the only thing
(08:59):
flying around. Uh, it would make sense that that's where
they would go. But they knew early on, regardless of
the flapping, that they needed to understand wind and how
wind worked with wings. And so they started going to
these little hills and mountains and they started going to
caves that had you know, they were looking for some
(09:20):
sort of predictable, constant wind so they could do some
early testing. And they realized, you just can't do it
with mother nature. You can't get a consistent wind, not
enough to get real data out of it and do
that math that we need so so drastically to make
this possible. Right so, and and initially we got that
assist from birds and that we knew wings had to
(09:42):
be involved. That the whole flapping thing really kind of
threw things off for a while. But because we knew
that there had to be wings, we knew that there
had to probably be some ideal or optimum shape of wings.
And that's really where wind tunnels first got their start,
wasn't testing different shape of wings or air foils. And
there was a guy back in seventeen forty six named
(10:04):
Benjamin Robbins who created a wiry arm um, which is
basically like a It was a centrifuge basically is what
he created. He had a hard time picturing this, and
there's only there's this one very rudimentary sketch that made
it even more confusing. Okay, so just just imagine you
(10:24):
have like a pole coming out of the ground vertically
and you have an arm attached to that pole, and
the pole can spin around in a circle like a centrifuge,
like one of those G force testers that they have
at and like, um, like astronaut training, you know what
I'm saying. Yeah, yeah, yeah, that thing. This is what
that guy invented. But it was like with wood and
(10:47):
in the dirt. It wasn't and it didn't go that fast.
But you could have fixed a like a wing type
that you were testing to see if it worked well
to the end of it and push it through the air.
And it didn't really help this guy figure out what
wings style or size was the best. What it helped
him figure out is that it doesn't have that much
(11:07):
to do with anything with flapping. We don't need to
be wasting our time inventing machines that that flap their wings,
because that's not it. It's all about this thing called
lift and drag and the proportion between those two. And
if you can figure out how to get more lift
and decreased drag. Then you can you can really make
some you can fly basically, And this was the very
(11:30):
first inklings of that that Benjamin Robbins came came up with. Yeah,
and what I saw was that Robbin's really kind of
pinpointed drag, like the shape is super important. And then
after him, Sir George Cayley had his own whirling arm
and he's the one that really figured out lift was
a key. After they realized the shape of the thing
matters the um more than the shape, like the size
(11:53):
of it matters. Size does matter, especially when you're flying,
especially when you're flying, and uh that if you could
just get a quick enough takeoff, you don't need to
flap at all. All you need is a lot of
speed at first, which they could have also gotten frankly
by if they would have kept looking at birds and
realized they eventually stopped flapping, they might have realized, oh,
(12:16):
you actually don't need to flap the whole time. You
can glide if you've got enough speed, right and and well,
actually a lot of the early flying machines were gliders.
It was one of the the Wright brothers were not
the first people to UM engage in in human flight.
There is a monk named Elmer of Malmsberry who has
the first recorded human flight back in ten fifty c
(12:38):
E not b C and um he he You know,
that was almost a thousand years before the Right Brothers UM.
But the Right Brothers are credited with with UM the
like an engine powered flight human flight. Right, So they
they were dabbling in what's what Kaylee and Robbin's well,
(12:58):
Kaylee especially figured out that you need thrust and there's
just nothing around that's light enough to produce enough thrust.
So Kaylee actually gave up and went and joined parliament
for a while before he finally created a flying machine.
Fifty years before the Right Brothers. He made his UM.
He made his coach driver test pilot it, and the
coach driver was so scared even though the flight was
(13:20):
successful that when he landed he was like, I quit,
I quit. I'm not. I don't work for you anymore. Yeah,
but George Kayley's very much overlooked figure in the history
of flight. He apparently figured out the general shape um
of a modern airliner back in Yeah. Alright, I say
we take a break, we'll come back and talk about
(13:42):
the first wind tunnel right after this. Alright, so Kaylee
(14:10):
has these whirling arms going terrible name, but it worked out. Uh.
Then enter a man named Frank h Win him. He
was another Englishman and he was in the Aeronautical Society
of Great Britain, and he said, guys, we need or
excuse me, gentlemen, we need a wind tunnel, and we
need it bad. And so in eighteen seventy one he
(14:32):
had the very first wind tunnel. Was twelve ft long,
about eighteen inches square, with a forty mile wind, which
is pretty good. It was. It consisted of your daughter going,
oh god, stinky has went dunne her breath. Isn't that
stinky yet? Kids don't really start to stink until later,
I think, yeah, until later. But the winds were powered
(14:56):
by a steam fan at the end of the tunnel,
and it worked pretty well. He was able to get
that leading edge of the airfoil and move it up
and down and change his angle angle of attack and
kind of see what shaped, uh and what angles worked
best with to get the best lift. But it was
still sort of choppy, and it was rough around the edges.
(15:18):
And if you really want to make this you know,
if you want to fly safely, you got to have
a really really really consistent, very smooth wind to work
with to get that data. And they still didn't have
one at this point. Now they still didn't, but they
were advancing by leaps and bounds here that people were
building their own wind tunnels. Because up to that point,
(15:39):
if you had in a design for an airfoil, for
like a wing size or shape, you had to build
it and then go take it out into nature and
test it and hope for the best, and it was
really expensive, really time time consuming. With your own wind
wind tunnel, you could make a model of the shape
and test it out yourself and then see this is
actually worth pursuing, or this as junk, and that's it.
(16:01):
That's what our dear beloved heroes, the Right brothers did
in Ohio outside of Dayton, Lorville and Wilbur Wright Um
built their own wind tunnel. These guys were just like tinkerers.
They owned a bike shop, but they were so fascinating
were following these developments in early flight that they just
kind of got into it themselves and they built themselves
(16:21):
a wind tunnel. They had like two different or two
hundred different types of wings. I believe that they messed
with selected the thirty best ones that they had developed
in their wind wind tunnel of their own construction and
design um And apparently I saw somewhere that by nine one,
after their wind tunnel tests, the Right Brothers, a couple
(16:41):
of bicycle repairment in Dayton, had the world's um most
accurate data scientific data on on flying and wings in
the world. And they'd come up with it entirely by themselves. Yeah,
and here's the thing with these wind tunnels, especially early
on in kind of still, it's not like they could
(17:02):
use that wind tunnel and come out with a surefire
product using math and uh and testing different designs and
shapes and tilts and angles. But it was such a
time saver and broken bone saver that you didn't just say,
all right, well, I think this might work. Let's go
and push our cousin off of a cliff or our
coach driver or whatever and see if it works. They
(17:24):
still had their failures, all of them did, But I
mean it would have taken I mean, god knows how
many more years if they didn't, like at least start
from a point of likely success thanks to wind tunnels.
But I mean, like, look at it. They went from
they finished their wind tunnel tests in nineteen o one,
they had their first powered flight in en three. Yeah,
(17:46):
I mean that's so it's amazing two years and it
definitely did accelerate it too. And so you can see
from the outset that that aviation and wind tunnels just
developed together, and wind tunnels developed aviation um. But the
first wind tunnels, like you said, they had a really
big problem, and that was the air that they produced.
(18:06):
The stream of wind was very choppy, very turbulent, and
your data was not necessarily reliable. It wasn't too terribly
much better than say, going out into mother Nature and
subjecting you know, the same model to those winds um
And that's a big problem. So one of the first
things that they figured out how to do was to
(18:28):
make the wind smoother so that you could get a reliable, smooth,
steady wind um in your wind tunnel whenever you wanted
to use it. Yeah, and that's where we come to
the modern tunnel, very very smooth airflow. And they have
five basic sections of and they're you know, they're all different,
but they have five basic sections. In a modern tunnel
(18:51):
that's the settling chamber, the contraction cone, the test section,
the diffuser, and the drive section. So we start out
with this swirling air and it's a big choppy mess
and it enters the tunnel and we'll talk about how
in a second, because it's kind of cool, little counterintuitive,
but it makes a lot of sense. Um it goes
into the settling chamber, which does exactly what you think.
(19:13):
It settles that air, straightens it out. They might have
these little honeycomb holes or a screen or these panels,
and that's just sort of the initial thing to sort
of get it nice and smooth and moving in the
same uniform direction. Yeah, and then it goes down. They
step it down through that contraction cone, and that just
I mean, it's like anything else. If you make the
(19:35):
the tube smaller, it's going to increase that velocity of
air flow. And that's where it gets to the test section,
which is whatever. And the test section depends on what
you're testing. If it's a desktop thing, the test section
might be twelve inches long and you might have a
tiny little model of an airplane wing in there, and
(19:55):
that's where the actual thing you're testing is and where
all the sensors are record all the data because you know,
you've got your visual that you've got these windows so
you can shoot TV commercials and you can look at
the thing. But there's also all manner of sensors to
pick up on all manner of UH data and observations. Yeah,
I think that's really cool that they still you know,
(20:16):
when they operate wind tunnels, they still watch through the
window because there's a lot to be gained visually from
from just human beings watching this stuff, and so you
want to you want to watch it right, Yeah, for sure,
especially when they got the green smoke thing turned on.
So after it goes through the um, the test section
(20:36):
enters a diffuser UM which kind of it slows things,
slows things down UM and maybe just exits the whole thing.
It's kind of the opposite of the contractor it just
opens back up right exactly. So there's UM, there's there
as far as breaking. There's a lot of different kinds
of wind tunnels, as we'll see, but there's really kind
(20:58):
of two categories too, broad categories. You've got open and
closed circuit, and an open circuit is where you have
wind going in on one end, going through the diffuser
and the honeycomb in the test section and then coming
out the other end blowing into the room and another
with the closed circuit. It's just basically an oval and
so when the wind is generated, it goes through the
(21:20):
it goes through the test section out the back, but
then bends around an oval track and then comes back
around again and through the contraction coning into the test
section again and again, and can just keep going rather
than just blowing out the other side. Yeah, and here's
the part that I said wasn't intuitive, but it's really
kind of neat when you think about it. The drive
section is where this fan is, and this is what
(21:41):
it's just generating that air flow. And I always just
thought a wind tunnel was a fan pointing at the thing.
They're actually behind the thing, because you don't want to
push air onto something, you want air being pulled over something.
And it it just makes total sense, but you ever
really thought about it, You just I always just pictured
(22:02):
a big fan blowing at a car, but the fan
would actually be behind the car and it's probably looping
around and smoothing out this entire way and then being
gently pulled over the car exactly. And in just the
same way that the fastest way to cool off, say
like a server room that you don't have good cooling on,
you just throw a box fan the opposite way. So
(22:24):
the boxman is blowing out into the regular room, but
at the same time it's sucking the air, the hot
air out of the out of the server room, and
cool air is rushing into a place that hot air.
So you're creating like an air flow that's much less turbulent.
When the fan sucks the air out, it's much smoother
than when it blows it in, which creates a lot
(22:46):
more turbulence. And that was the big problem that was
facing like the Right Brothers and some of those other
early wind tunnel creators, is they their fans were blowing
on the front of their models rather than having the
fan behind it sucking the air over the models. Right.
So these little models they're kept in place, sometimes around wire,
(23:06):
sometimes around these middle poles. Uh sometimes I think they
really super high tech ones use um super strong magnets
to actually hold them in place, which is pretty cool.
And then again you've got all these sensors all over
the place attached to the model measuring I mean, we'll
see it gets really really deep. But just at the
(23:27):
outset you can measure like wind velocity and air pressure
and temperature, and if you're talking about airplanes, roll and
yaw and drag and lift, and I mean, you can
kind of do anything you want in there. And if
you have, like if you're testing an airplane or a
scale model of the airplane you're gonna build, it's on
(23:47):
something called the sting, which is a pole basically that
goes into the airplanes bottom. But but then inside the airplane,
the airplane is not attached to the pole. It's attached
to something called a balance. And it's like all those
sensors you just mentioned all in one instrument, like a
cylinder tube, and as the airplane moves and pitches and
(24:08):
yaws and rolls and and gallops and all that stuff,
not gallops, So I made that part up. UM, it's
it's acting on those sensors and the motion, the mechanical
motion on those sensors is translated into an electrical impulse
and that travels down the stinger into the computers which
are picking up all of this data in real time
(24:29):
and UM logging it and creating new new versions of
the UH the model based on that stuff. It's pretty amazing.
What's even more amazing that makes sense that that exists today,
That's existed since like the forties or the fifties, and
in much more primitive form, but essentially the same thing
that we use today, the same kind of balance what
(24:50):
has been around for decades. Wasn't there a Simpsons joke
about y'all control? Yes, yeah, when they had one of
those like backyard pockets now with yaw control and didn't
like buzz Aldrin or something, say like, wow, look at
that y'all control. I think so that was good stuff. Uh.
Some other things that they measure, which you might not
(25:13):
really think about existing is viscosity and compressibility, or the
tackiness or the bounciness of the air itself. So when
you're thinking about air blowing over a car driving down
the road, you don't think of that air is like
being sticky necessarily. But when that air is moving over
the hood of that car, in the top of that
(25:33):
car or the plane or whatever it is, Uh, those
little molecules are gonna hit the surface and just very
very briefly, they're going to cling to that surface, and
that even for that brief brief amount of time. It's
gonna create a little boundary layer of air next to
the thing that you're trying to measure air flow over. Yeah,
which is, like I said, a very big deal. And
and yeah, an individual air molecule is going to stick
(25:56):
for a nano second, just some ridiculously short amount of time.
But there's so many air molecules that they essentially just
replace each other as fast as they can move. And yes,
they create this this this boundary layer. And as far
as aerodynamics is concerned, your your say, your car blow
go like driving through this wind that's that's sticking to
(26:17):
it um now has a different shape. That boundary layer
creates a different shape or extends it outward beyond the
actual physical shape of the car. And so, yes, very
much so. And then so so when you're trying to
test like how fast the car is going to go,
how many miles per gallon it's going to get that
kind of stuff. That boundary layer makes a tremendous amount
(26:41):
of difference because it changes physically changes the shape of
this this thing when it's out there traveling at high speeds.
So one of the great benefits of an air tunnel
is you can test, like, what boundary layer is produced
by this particular shape of this car under this condition.
You know, if it's um humidity, but you know forty
(27:01):
degrees ferrent height. Uh, and they're traveling at eighty miles
an hour, what kind of boundary layers produced? Okay, well
what about seventy five an hour at the sixty percent humidity.
You can just change all these variables, and the wind
tunnel allows you to simulate it in in in Basically, UM,
get all this data in real time. UM. Just lickety
(27:22):
split basically. Although one other thing, I just want to
say this, we're making it sound like this is fast.
This is actually, and has been, especially until the age
of computers, very arduous work. Because if you wanted to
change one variable, if you said, well, this headlight is
actually causing way too much drag, you would have to
switch that headlight out with your next model and run
the same tests over and over and over again with
(27:42):
the different different um conditions and log all that data.
So it was really arduous before computers, and you kind
of get the idea that aerodynamics as a field of
study is really given over to computation. Like there has
been a huge savior for that field and helped it
along and saved a lot of people a lot of time. Yeah,
and you mentioned things like humidity and temperature um. There
(28:07):
are all different kinds of wind tunnels, and they can
be very specific as to what they want to test
or very broad, but they're they're all able to do
things like that. You can dial in a temperature, you
can dial in um atmospheric pressure if you want to
see what something' is like on Mars, which they have
to do if you want, like the Mars Rover to
be successful. They can. They can ice up a plane
(28:29):
wing just by introducing refrigerated air and spraying a mist
of water that freezes and lands on the wing, and
you can simulate all these different things humidity and temperature,
And it's just amazing that that they thought to to introduce.
You know, at first they started out probably just looking
at aerodynamics of flow over a thing, but as they
(28:52):
got more and more specific with their needs, they just said,
you know that we can design these tunnels to kind
of do anything we want to do, like recreate any
and vironment you can think of. Basically, Yeah, it's true,
and I mean like as as we started to build
planes that go faster and faster. We started building tunnels
that simulated that really high speed travel, and so we
(29:12):
have hypersonic and supersonic um wind tunnels that don't use
fans at all, but they use like bursts of compressed
air that blow right onto the model. Those do blow
at the thing instead of sucking behind it. Right. Um.
But it's it's a huge release of of air that
is traveling so fast it simulates you know, like a
(29:32):
jet flying through you know, hundreds of you know, millions
of miles an hour probably yeah, or hey, what's it
like for a rocket human capsule too, uh to come
back into Earth's atmosphere at the and and not burn
up like they can simulate those temperatures. Yeah, there's one
(29:53):
in I think North Carolina. No University of Texas at
Arlington has something that can simulate that goes up Torees Ferren.
It's crazy, man, it is. It's a wind tunnel for
all in times of purpose. It's a wind tunnel. But
they have built these things so that they can simulate
basically any any climate. And you know, we talked about smoke,
and it's always fun in those TV commercials to see
(30:15):
the smoke blowing over the thing. And it's a nice
visual to sell cars that look super aerodynamic in our
super aerodynamic. But that visible flow isn't just you know,
for the stoners in the lab department, like late at
night to play around with, although they probably do that,
but they flow visualization is a real technique. Um, you
(30:37):
might just have colored smoke, you might have liquid, like
a mist of liquid. You might have they use this
colored oil sometimes that uh you can see like the
wind pushing the oil along the surface of whatever model
you're using, and then they've got these high speed cameras
capturing all of it. And again it's just, um, it's
another variable they can actually look at rather than just
(30:59):
using numbers and data. Yeah, I saw one, um one
was taking photographs of like two thousand frames per second.
That speed it was, but it was they were testing
like a rocket or something or model of it. Should
we take a break, Yeah, let's all right. We'll be
right back with more on wind tunnels right after this.
(31:43):
So Chuck, I was like a lot of this really
breaks my brain. It's one of those things we're like,
oh yeah, I totally get this on the surface. Let
me scratch a little deeper. I don't understand this at all.
And the reason why is because you know, aerodynamics requires
a lot of math and formula and all sorts of
calculations that I'm not contrated that I'm not currently capable
(32:04):
of doing that. But one of the things that I
tried to shake down was when you do a scale
model of something, do you have to scale down the conditions?
And it turns out I wasn't the first one to
think about this. Other people have, including people who work
in wind tunnels, and apparently they do not do that.
(32:25):
They will say, subjected to the same wind speed as
they would like the full size one, but then they
go back and use math to adjust um these that
all the different variables and again, you know, we talked
about pitch and y'all, role um, drag lift, all sorts
of stuff. I'm sure quite a few things and variables
(32:45):
that you and I haven't even come up with um
or run across during our research. But in each one
of these interacts with each other thing, right, So it's
like one of those things where you know you have
a eleven possible hoppings for a pizza and that creates
twelve million potential combinations. It's a brain breaking amount of
(33:06):
math involved exactly. So that's what they're doing. To scale
it down and scale it up. They can say, oh, well,
it produced this data. If we run it through these
these you know, formula um like, we can show that actually,
like it will have this effect in the in the
real world. They're using that level of math. Anybody who
(33:27):
can do that with math, I admire them deeply. If
you're listening out there and you can do stuff like
that with math, my hat is off to you because
I will never be able to do that, and I
admire you. Yeah, And you know what, we've taken some
heat for kind of beating up on math a little
bit is like boring because we were English and journalism
guys and history guys. But uh, I've really come to
(33:50):
appreciate math and doing this show. I'm no better at
it and don't care to be, but I appreciate the
You know, math is the one thing that doesn't care
about what you think about it. It doesn't care about opinions,
and there's no interpretation or nuance. It's just it's just math.
And like what makes like to look at these to
(34:11):
look at a math equation that would take a model
of an airplane and a tiny little thing and a
tiny wind tunnel and then say, well, now we just
scale it up to this, and this is how you
do it right, just multiplied by time. It makes me
so nervous, But a real mathematician would be like, this
is the last thing you should ever be nervous about,
because it's it's just math. It's just right there. Well,
it's just and they probably the idea of them of
(34:34):
doing public speaking would probably scare the Jesus. And the
thing is exactly like, different things attract different people, and
that's great because that makes the world a lot more
rich and complex that you have all these different people.
If everyone was in the math, it would be a
pretty boring place, or if everybody hated math would be
a pretty boring place to Like, you need all different kinds,
different strokes for different folks. Makes the world go round,
(34:56):
I think, is the rest of them. All. Right, Let's
talk about some of these wind as in the world,
because they're amazing. NASA has one at Ames Research Center
in San Jose or near San Jose, biggest in the world,
biggest one hundred and eighty feet tall, dude four hundred
feet long, and the test section on this thing is
eight ft tall and a hundred twenty ft wide, so
(35:17):
you can put a full size jet plane in that thing. Yeah.
I saw that. I was like, well, what kind and
they said seven thirty seven. Yeah, that's pretty good that kind, buddy,
pretty pretty good size. So yeah, that's a I don't
know if they call it this, but I hear here
henceforth call it the Big Man with jam. Yeah. It
uses six four story high fans, each of which is
(35:41):
powered by six two thousand, five hundred horsepower motors. Six
fans each as tall as a four story building. That man,
that's amazing. A hundred and fifteen mile in our winds
is where it tops out, yeah, which is pretty great.
Um that there's also a lot apparently. I was reading one,
(36:02):
um uh, some like blog posts I think on like
a Formula one site, and they were talking about how
like every single company, every single racing team has in
its facility of full size wind one like it can
hold a full size Formula one car the cost of
like six million dollars or whatever. But they are um
like cutting edge as far as um aerodynamic study is concerned. UM.
(36:28):
And the reason why is because like if you can
shave a second off of somebody's time just by reconfigure
the engineers reconfiguring the shape of a fin or a
tail or something like that. That's that you just it
just paid for itself basically because it may have just
one like the you know, good job there, Yeah, thank you.
(36:49):
So there are NASCAR's obviously obviously got a couple of
these things in North Carolina. The home of NASCAR Aerodin
wind Tunnel. UM that is in North Carolina, and it
tests full sized stock cars. There's no one called wind
shear there. Um. This is a closed circuit tunnel that
actually has a treadmill in it for cars. It's got
(37:11):
a built in rolling road. Yeah, saw that in a
few places, like BMW has one with the rolling road.
You know what's interesting to me too, is so we
saw that the aviation industry and UM and wind tunnels
kind of grew hand in hand. The auto industry didn't
really look up wind tunnels until about the fifties is
when they really started running their cars through those, and
(37:35):
they went, boy, these cars are not aerodynamic. Now look
at it. Look at that yaw control. Though. Yeah, I
love those old cars. Though I used my old Plymouth
Valiant that I used to have. Um. This is obviously
way before anyone ever thought of anything like anti lock breaks.
And one of the most fun things I would do
(37:55):
when I was driving with friends on an empty road
late at night was get up to about fifty miles
an hour and just slam on the brakes. It was
so much fun, man, it was great. You would just go.
You would slide about a hundred feet before finally coming
to arrest. That was a great impression of slamming on
the brakes too, by the way, it was good and
(38:16):
you know it. It was like we called it the
sled because it was just this big, heavy hunk of metal.
It's not like I was sliding all over the road.
I was just sliding very straight in a line. What's
the opposite of aerodynamic that Plymouth Valiant? There you go, um,
sluggish like a what sponge? Yeah, that's about right. So UM,
(38:39):
I think we should wrap this up on the future
of wind tunnels because people have been saying like, well,
wind tunnels are are dead. Now we've got computational fluid dynamics,
which is basically computers can figure all this out if
you put a shape into you know, auto CAD and say, computer,
figure out what you know will happen if I try
to fly this under these conditions, It'll tell you um.
(39:02):
And they people have said, well, you know, it takes
a lot of work and a lot of money to
run and build and use wind tunnels. UM. So I
think they're probably going away people who work in wind
tunnels saying no, to not do away with the wind tunnels.
We need them still because yes, computation UM helps a
lot with the early work, but when you finally have
(39:23):
something that you need to prove, you really kind of
want to see it in real life to make sure. Yeah,
you want to see that smoke yourself. UM. And you
know computer simulations can't simulate green smoke very well. You've
got to see that in real life. So they they're
saying that this is complementary technology and that they really
we need to keep our wind tunnels around because we
still need them. Yeah. And I think we'd also be
(39:46):
remiss if we didn't say it's not just um vehicles
and seeing how like a space shuttle or a car
or a plane or a dune buggy might might run
in the wind. Um. If you want to see how
airflow if X like a computer U and components in
a computer, you can yeah, good point, like how they come,
(40:06):
how they cool computer chips. If you want to figure
out the very best design for a wind turbine or
wind farm, then you can use air tunnels. Um. There
are lots of other different uses that you don't think
about just on kind of everyday products. Sometimes. Yeah, there's
a I have to say, there's a a Virginia Tech.
There's an ann echoic, an echoic I believe, wind tunnel
(40:27):
where they test wind turbines to see what kind of
noise they're going to make. And they have so the
walls are as far as the wind is concerned, it
has four walls, but as far as sound is concerned,
it has three because one of the walls is made
of kevlar, so wind won't go through it, but sound
will code right through it like it's not even there.
(40:47):
So they can take accurate measurements of what's going to
happen when the wind hits this turbine, what kind of
sound is it going to make? And they're making the
country folk who live among wor wind turbines much happier.
That's awesome. Yeah, So that's it for wind tunnels, everybody.
There's probably more to it, but it's far, far beyond
chucks or my grasp. So again, hats off to all
(41:10):
the aerodynamicists in all of their maths. Ah. If you
want to know more about wind tunnels, go check stuff
out on the internet. I hear there's a man with
the page boy haircut who does a pretty mean demonstration.
No no, no, that's just the printing press. Okay, I
thought he was a factotum. He might be renaissance man. Um. Well,
(41:30):
since I said renaissance man, everybody, it's time for listener mail.
I'm gonna call this on Wetlands. And this is one
from Brian from Queens and this is very cool. I
didn't realize this. There was a a music venue in
New York when I used to live up in New
Jersey called Wetlands that I would go to, and I
never knew that was kind of a cool story behind it,
(41:53):
and now I do. So this is from Brian and
he says, you know, the New York City area is
surrounded by salt marshes and there are tons of or
it says, protecting New York City's natural flood and pollution
guards as you described them um in the nineties and
throughout the eighties and nineties that the Wetlands Preserve. It
was an activist nightclub named for the land that Lower
(42:14):
Manhattan was built on. The club was on Hudson in Tribeca,
very much Downtown Manhattan, which back in the early settlement
by the Dutch was in subsequent subsequent takeover by the
English was all Salt Marshes. Wetlands Preserve, colloquially referred to
as the Wetlands was open from eighty nine to two
thousand one. Dual purpose was to create an earth conscious,
(42:35):
intimate nightclub that would nurture live music, integrated with a
full time environmental and social justice activist center in the
club's basement. Wait, what was the years that was open?
Eighty nine to two thousand one? There is a hundred
percent chance that Jewel played there. He doesn't list to it,
but I bet she did. Okay, whoa he lists? He
(42:57):
lists a few, but he also links to many more,
and she's probably in there. I think I saw wean
there if I'm not mistaken. But he said downstairs. Activist
planned protests, made pamphlets, wrote letters to politicians and lobbies,
generated boycotts and educated club patrons, while upstairs we hosted
or they hosted some formative performances for legendary rock brands
(43:17):
like Pearl Jam, Dave Matthews, Merein Five, Oasis, Widespread Forget,
Jewel Fish, Rise Against Fishbone, Bikini Kill, Blind Melon, and
Jewel Yes. The nightclub raised revenue for the Activism Center's
effort efforts, and the intern Activism Center staff and volunteers
educated nightclub patrons on environmental, social justice, and animal rights
(43:41):
issues through posters, educational displays, literature, et cetera, and film screens.
The New York based Wetlands Activism Collective continues. The club
is shut down, but they continue it's environmental, social and
political activism to this day. And that is from Brian Stolary. Nice, Ran,
that's pretty great. I never knew that. I think it
(44:01):
went to a couple of shows at Wetlands. Oh you did,
and I never knew that there was something else going
on there, and I kind of had forgotten about it.
I wonder if when you showed through, like the Cops
Cop Narc that was Brian. You said, Yeah, Brian Stolary,
that's pretty cool. Thanks for filling in the blanks for
(44:21):
us there Brian um and if you want to be
like Brian and filling some blanks for us, you can
send us an email send it off to Stuff podcast
at iHeart radio dot com. Stuff you Should Know is
a production of iHeart Radio's How Stuff Works. For more
podcasts for my heart Radio is at the iHeart Radio app,
Apple Podcasts, or wherever you listen to your favorite shows.
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