Today, we are testing
ourselves in the wind tunnel. – Let’s hit it.
– ( fans whirring ) Gav:Well, that doesn’t
mess around!Dan:That’s a full 45
right there.Why don’t we start
testing some elements? ( wind blowing,
spraying ) Gav:( laughing )
Look at that liquid!I brought my own balloon.It’s a condom. ( screaming ) Gav:That is the stupidest thing
I’ve ever recordedin slow motion
in my life. Well, that was a
beastly wind tunnel. It really was.
It was what? 80 miles
an hour? Yeah. The shots of you
in the water, especially ’cause we
backlit the water. It just looked really cool. Like, it was fascinating
to see how the air was moving around you,
but it also just looked wicked. It was like commercial grade
footage. You look like
a certain singer –from a 90’s music video.
–( Dan laughs )( R&B music plays )Gav:Oh, that’s magic.♪ Yeah, yeah ♪I also think that you
condom sailing on a skateboard might be
the most bizarre thing
we’ve ever shot. You know, that will be
one of the most fun things
I’ve done this year – for sure.
– ( laughs ) Something about your
flat hair, with your smug face,
with that flapping
in the wind.Goodness, gracious me.I didn’t expect it
to work and then it worked and I was so happy. It was so much fun. Well, we thought it’d
be a good idea to learn a little bit
about the facility so we talked to a bloke
who works there called Kevin. Let’s kick it to Kev. – Dan:Kevin.
–Hi, Dan.Hey, so you’re one of the
aerodynamicists at Mira, right?
Have I got that right? – That’s right.
– Yeah. That’s a cool
job title. Damn good occupation. So what does that
actually mean? Like what do you do? So, one of the jobs
I have here is to essentially characterize
how vehicles behave from an aerodynamic
point of view in terms of drag, lift,
front lift, rear lift. So what are some of
the fastest speeds of wind
you’ve seen in this tunnel? Um, so we can– we usually
operate up to about
80 miles an hour. And that’s like equivalent
to like a hurricane or
something? – Uh, um–
– Light hurricane? – Yeah, a light hurricane.
– A light hurricane? – A breezy hurricane.
– They can go quite strong. So, how do you feel
about the fact that you’re an aerodynamicist
with a PhD, and does very
scientific things, and we come along,
whip out a condom,and fly along the floor
with a skateboard.You have this huge
scientific facility, you know, do you mind?
Is that– Well, from an engineer’s
point of view, I kind of have to be
very professional about everything and that
basically makes my day job a little bit dry, so to have something
interesting happen for once makes for quite
a nice change, so… And I bet in the– what?
70, 60 year history
of this place… Kevin:Yup.Gav:…It probably not had been
done before that.You may have very well
set a record there. Yes. It’s quite an honor
that you lasted in it,
to be honest. That is great. Thanks very much, Kevin,
for letting us mess around
in here. – No, thank you.
– It’s a real honor. Thanks a lot.
That was really so much fun. – That was a lot of fun.
– Glad you had fun. All right, back to you,
Gav and Dan. Oh, thanks, us. It’s amazing how many
of the things we filmed is so heavily influenced
by aerodynamics. It’s not just things
we film though, I remember I used to ride
my bike to school, one day it was really windy I was, like,
ten minutes late for school, so as I walked into
the class, and the teacher was like,
why are you late? and I was like,
“It was windy.” And she just goes,
“Get out.” And the class just
laughed at me. Did you get laughed at
a lot as a kid? Let’s– ( stammers )
Let’s leave that, all right? To find out more about
aerodynamics, and why I was late
for school, we’ve brought on someone
who is clearly never late
for school, Lisa, who’s an aerospace
engineer. – Thanks for coming.
– Thank for having me. Hello. Were you ever
late to school? – Oh, no, definitely not.
– Gav: Definitely not. I’d love to get
your opinion on some
of the aerodynamics of Dan and I,
so why don’t we go over
to the screen… – Sounds good.
– …and have a little look. – Okay, first clip.
– The idea behind that was, it was that I was trying
to sit down fully,90 degrees with my legs,but I couldn’t do it
unless I had that little
bit extra where I put my hands out
to help me… – Makes sense.
– To get a bit more… Yeah, just a little bit
more track. It was amazing the difference
that this made. – Mm-hmm.
– Gav: Over here what I’m doing
is I was holding my lab coat out,
and I was trying to makeforward progress
and the more I had it openI actually couldn’t
go anywhere. It was like
holding–Oh, that makes sense,
you had a parachute
behind you… – Yeah.
– …at that point. Lisa:So this is a great
example of the four forcesacting on you all at once.You are trying to
exert thrust on yourselfby moving yourself forward.You’ve got the drag
of the windpushing on you
trying to keep you back.You’ve got the weight
of your bodykeeping you on the floor,and then the lift,
you can actually see
a little bitin the parachute
from your lab coatand just that kind of lift
and pushing up on your chest
as you lean forward, too. So all of those forces
are acting on you at once even as the wind is blowing
in one direction. I look like I’m totally
chilling there. Gav:You’re having the time
of your life.Dan:Usually, it’s so much
effort to do that,but it was so easy
because the wind.But now that it takes 80 miles
an hour to do that for me.And now I’ve gone
for a jump here.
By me jumping forwards, I went almost straight up
and came back down like this. Wow, you’d be so late
for school. ( laughter ) Gav:
If I had a lab coat onand I walking through that
to school,– I wouldn’t get there.
– Yeah. ( laughs ) Lisa:Couldn’t make it.Gav:Uh, this was actually
the scariest thing that I did.I was wondering
what would happen
if I went on the floor.But as soon as I held up
my lab coat like a parachute.Lisa:Yup.It just started sucking me
along the floor. And I got some significant
distance here.See, here’s me, I’ve got–
I’m going too fast.So I’ve put it down
and I’m still, – the momentum is still–
um, is still–
– ( laughter ) Apologies for that.
No one wants to see that. So why don’t we move on
to a little table top
experiment? So we’ve been to
a multi-million pound
wind tunnel in England and now for our table top
experiment, we’ve got a little
wind tunnel that didn’t cost
millions of pounds. – Multi-pounds?
– Multi-pounds, though. – Yeah.
– Can’t get it for a quid. It’s just a normal fan
with a tube, a bunch of tape,
and a lovely clear
wind tunnel area. So we can test out
these two cars. We got an old boxy one,
and a lovely streamlined one. Because we can’t see air,
so we want to know
what’s gonna happen, we’ve got this
vaporizer here, which is gonna create
a bit of smoke for us. I’m gonna shove it in
and hopefully we’ll see the smoke going around
the cars in different
patterns. Gav: Why don’t we start
with the boxy one. What is your prediction
for this then? I’m not thinking
it’s very aerodynamic. – ( laughter )
– You’re probably just
gonna see smoke going everywhere. ( machine buzzing ) Yeah, you can see it
just bashing against the wind-screen there. Lisa: Yeah, that blunt front
is not doing it any favors. Gav:
Shall we try the second one? – Yeah.
– A little bit bigger. But we’ll pretend that
it’s the exact same size. ( scoffs ) Gav: All right, I’ll give it
some action. ( machine buzzing ) Lisa: So for this one
you can actually see
the smoke – rising over the top.
– Gav: Yeah. It’s coming all the way
back here, and then it’s coming down
at the end. Exactly. This car is much
better designed for fuel economy
than the old car. And this way you save drag,
and when you save drag, you save gas,
and when you save gas,
you save money. What’s the weirdest stuff
you’ve put into a wind tunnel? Some of the oddest things
I’ve seen would have to be
a trash can. Why would you need
a trash can to be– Is it to stop
from blowing away
in the wind? Exactly, you don’t want it
rolling down… Gav: Actually makes
total sense. …once you’ve put it
on the street. Actually, I’ve got something
I want to put in here. Thinking about it,
hang on. – Us.
– Oh, us from episode one. Yeah. Obviously, I assume
I’m going to be less
aerodynamic. – ( chuckles )
– Let’s put me slightly there – and you slightly off.
– Okay. ( machine buzzing ) Gav: Oh, yeah, it’s coming
around you, It’s going through
your arm holes. Dan: It just goes
like nothing through you. – ( Gav laughs )
– Dan: It just completely
avoids you. Gav: Do you learn the same
information from doing it
scaled down than you do full size? You can learn most
of the information you need from a scaled test. Usually it’s a much bigger
scale than this, but you definitely can. I like that. I like it when,
just like, physics and principles
just scale up perfectly. Thank you very much,
Lisa, for joining us. – Yeah, I enjoyed it.
– And teaching us about
aerodynamics. Well, hopefully
you enjoyed that video. Feel free to watch
other episodes from
“Planet Slow Mo.” Make sure you check out
Dan’s condom sailing, – that was amazing.
– Worth it. And you can subscribe
to the Slow Mo Guys
if you’d like. It would make us
a bit happier,
wouldn’t it? – Mm-hmm.
– You have a smile? Not quite as happy
as when I was using – the condom as a sail.
– Well, obviously not. That was up there.