- Back in October, the SSC Tuatara set the record
for the fastest production car in the world
at 316 miles an hour.
That is crazy fast for a production car,
but it got me thinking,
what's the top speed any car has gone?
Well, it turns out it's over double that, 763 miles an hour.
And that record was set...
Hold on, is that right?
23 years ago?
Well, car technology has obviously advanced it
then so why hasn't anyone beaten this record?
- Well, I mean the old textbook you can go and buy
that tells you this is how you design
a 1000 mile per hour car, right?
- Well, that's Dr. Ben Evans.
And he's part of the team looking to break that record
by building a car to hit 850 miles an hour.
And 850, that's cool and all,
but you know what else is cool?
1000 miles an hour.
Is that even possible?
I mean, what does it take
to make a car go 1000 miles an hour?
Well, today we're gonna break it all down
and it turns out it's pretty, pretty complicated.
So let's get into it.
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Big thanks to Audible for sponsoring today's episode
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Now your old uncle Jerry over here
has a lot of free time on his hand,
and there's only so much birdwatching I can do.
I've seen literally all birds,
but I heard about this thing called the interweb book thingy
and it's called Audible.
I found out they had these things called audiobooks
where a voice reads me a book through this headphone things.
It's great.
A voice reads to me.
Okay, what the heck it's magic!
And I've been listening to Greenlights
by Matthew McConaughey narrated by Matthew McConaughey.
You know, I do pretty good Matthew McConaughey impression.
All right. All right. All right.
Nailed it.
Now Audible isn't just limited
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Okay, I gotta get back to this audiobook.
Take me away Matthew, take me away.
I'm picturing him with his shirt off right now.
You don't know it, but he's naked.
All right quick physics recap.
In order for a car to accelerate,
there has to be an imbalance
between the force pushing it forward
and the resistance trying to slow it down.
As long as there's more forward force,
the car will continue to accelerate faster and faster
until it's met with an equal amount of resistance
at which point it will even out at its top speed.
So to help us visualize this, made a little Donut balance.
And on this side, oh (beep).
This side will represent the forces necessary
to drive the car forward.
And this side represents the forces creating resistance.
Let's say this shot of liquid equals 100 horsepower,
about the same as a Mazda2.
Now on a frictionless surface
with zero resistance in a vacuum,
you wouldn't need more than 100 horsepower
to get to 1000 miles an hour.
But in the real world, that 100 horsepower,
it's gotta go through a drive train
which creates mechanical resistance.
It's gotta overcome rolling resistance from the tires,
and it's gotta push back air resistance,
pushing back on the car.
Now these forces create resistance on the car
which is why 100 horsepower Mazda2
isn't breaking the sound barrier.
In fact, it's barely breaking 100 miles an hour.
That's a 10th of the speed we need.
So to go 10 times faster,
why don't we try giving it 10 times more power?
So now we're at 1000 horsepower.
1000 horsepower 1000 miles an hour.
Big bang boom we got it.
Well, it turns out that it's not that easy.
An actual 1000 horsepower car, like the Bugatti Veyron
it only reaches about 250 miles an hour.
And one of the main reasons is more air resistance.
The faster you go, the more it stacks up.
(chuckles)
Now let's actually look at the equation
for determining air resistance.
It includes the density of the fluid
which is just our atmosphere,
the velocity of the object, that's how fast it's going,
the coefficient of drag, which is just a measurement
of how well the shape of an object can move through a fluid,
and the cross-sectional area.
But really the most important thing
is this a little two right up here.
Because the velocity is squared,
it means that an increase in speed
results in a quadratic increase in air resistance.
Meaning that if you double your speed,
the drag force it doesn't double, oh no, it quadruples.
So we have a few ways in which we can combat this.
We can keep increasing the power or we can reduce the drag.
Well, sometimes reducing drag isn't an option
because it can be the only thing
keeping the car on the ground.
Passenger cars naturally have a shape that generates lift.
Look at the cross section of an airplane wing
and look at a car, they look pretty similar.
Now if we didn't do anything to combat the lift,
and then a car like a Mercedes A-Class
with the lowest coefficient of drag for production car
going about 250 miles an hour would generate enough lift
to counter 98.3% of its own weight.
The car would be the equivalent of 55 pounds.
Now a bump in the road or slight breeze
would be enough to knock the car off course
and the steering, well, it would be almost useless
as front tires would have no traction.
So to combat this, we need to add some downforce
but that downforce inherently creates drag.
So reducing drag is pretty much out of the question for now.
Our only option is to increase power.
- [Man] More power baby.
- So if this is equivalent to 100 horsepower,
then this is equivalent to 10,000 horsepower
about the same horsepower that's in a top fuel dragster.
And these drag racers can hit 300 miles an hour
in under four seconds.
But dragsters like this only run a quarter mile at a time.
Well what if we just say,
we just let one of them keep going?
Could it reach our goal of 1000 miles an hour?
What do you think?
No, they can't.
And the easiest way to explain why this is,
is because dragsters are built so specifically for one task
that they can barely survive just one run that they do.
Their clutches, literally they last one run
during which they weld themselves together from friction.
So if we wanted a dragster to keep going,
you're gonna need more cooling, you'd need more fuel,
you need a bigger transmission,
you need beefier engine internals.
And all of that means you have more weight,
more weight means we need more power, which means more fuel.
And to have that more power, we need to cool all that,
which means more weight.
It's a snake, eating its own tail.
Hmm! Yum, yum!
Ah, I love my tail.
Hmm my tail so good.
Yum, yum, yum!
And we haven't even gotten into the mechanical limitations.
So let's look at the Veyron for instance.
Now forget wind resistance, forget rolling resistance,
forget parasitic losses and all that jazz.
It can still only go as fast as its engine can spend.
So say we want the Veyron to reach 500 miles an hour
with its current rev limit of 6,600 RPM.
We could on paper do that.
And in fact, we did the math.
(audience laughs)
We would need the last gear ratio
and the transmission to be 0.42
which would be something around like 15th gear
if we had to step it all the way up.
Or we need 53 inch wheels,
which would be a pretty ball away
to solve this physics problem.
And while that works on paper,
it doesn't account for parasitic losses, component strength
and the added unsprung weight of the wheels.
Not to mention, the engine would need way more torque
to turn a system that big.
Now land speed record cars
have come up with a solution for all this,
but it isn't more torque it's no torque.
No torque.
- As soon as we hit kind of four hundred-ish
that sort of region 400 miles an hour or so,
that's when the switch had to happen
to thrust driven vehicles.
- Now, this is Dr. Ben Evans aerodynamicist
on the Bloodhound LSR Land Speed Record Project.
The current car going for the record.
- And it just becomes the more natural way
of propelling yourself forward
once you're at these sorts of speeds.
- Now what he's talking about
is rocket and jet powered cars.
With these there's no torque measured
because nothing is turning.
Instead, we have pounds of thrust pushing us forward.
How much thrust?
Well, the land speed record holder
from the 1970s reached 622 miles per hour
using a rocket engine making 22,500 pounds of thrust
which in liquid horse juice terms is about this much.
Mazda2, 1970s land speed record holder.
(heavily sipping liquid)
Now this is about 58,000 horsepower.
Now the car was called the Blue Flame
and it held the official land speed record for 13 years,
which actually brings me
to the next problem in this equation.
And that's the record itself.
The land speed record is an official FIA world record
and to hold it, you can't just reach the top speed,
oh no, you gotta stay there.
And the record is for a flying mile
which means that the speed is the average taken
over a whole mile and then it's averaged
against another run in the opposite direction
within the same hour.
Now the Blue Flame was like a bottle rocket,
it relied on its lightweight and bursts of thrust
for its speed.
Now that design only gets us so far
because after 650 miles an hour,
air pressure begins to increase
as we enter a space called-
- [Heavy Voice] The Transonic regime.
- No I'm not talking about Jared Leto's cult.
Although Jared Leto hit me up, I'll be part of your cult.
- Essentially the transonic regime
is as soon as there's air flow around the vehicle
is traveling faster than the speed of sound.
And that happens before the vehicle itself
gets to the speed of sound.
And that's when drag really starts
to build up around the vehicle.
- [Narrator] So basically as an object approaches
the sound barrier,
the air begins to stack up on the nose of the object
like a pile of pancakes that are harder to push through
than your normal air.
And once you break that sound barrier,
object pokes through that pancake and they break apart
just like this analogy and you create a sonic boom.
At least that's how it works in the air.
On land that sonic boom hits the ground you're running on.
- The fact that you're giving that spray momentum,
leads to a drag term and in kind of high speed motorboats,
they refer to this drag as spray drag.
And it's a similar phenomenon for us.
So we've termed this additional drag,
which, you know normally as an aerodynamicist
you don't need to account for, a spray drag.
- So you can see why it'd be a lot harder
to break the sound barrier on land than in the sky.
And it wasn't until 1997,
50 years after Chuck Yeager broke the sound barrier
in the Bell X-1 that the sound barrier
was just barely broken on land by the ThrustSSC.
All the components and power needed meant
that this super sleek looking plane
with wheels weighed 10 tons
and made the equivalent of 100.000 horsepower.
A thousand times more power than our little Mazda2.
Just to get a peeky tow across the sound barrier
for just a second and a record speed average
of 763 miles an hour.
We're not even close to hitting 1000 miles per hour.
So how much more do we need to get there?
Well, this is where Dr. Evans
and the team building the Bloodhound LSR come into play.
Now it's the current contender for the land speed record
and it's scheduled to make its run soon
in the Hakskeenpan of South Africa.
Now the Hakskeenpan is a dry lake bed so flat
that you can see the curvature of the earth.
Over a 10 mile stretch, the elevation changes
by only 300 millimeters.
And it's even flatter now
because the Bloodhound team removed 16,000 tons
of stones by hand.
Now with the equivalent of 135,000 horsepower
or 10 of these gallon jugs, Bloodhound has already made it
to 628 miles per hour in test runs.
And it's gonna go a lot faster.
So yes, Bloodhound in theory could go 1000 miles an hour.
It's got the thrust, it's got the drag coefficient,
it's got the crazy team behind it.
But there's still some holes in this equation
that you just can't slap a Mo Powa Babeh Sticker over it.
And we've talked about g-forces and their effect
on the body in previous episodes.
But the main thing you need to know
is that sustained g-force is way worse for the body
than instantaneous g-force.
In a crash, you might experience 8g or more for a second,
but in land speed record attempt,
if you wanted to maximize your use of the space,
the driver would experience sustained G
from the moment of launch all the way up
to the moment they pull parachute.
And then there'd be more sustained G
as the car decelerates to stop.
- In principle, I mean the only way
you can overcome that barrier
of fundamentally how much distance do you have
is accelerate quicker, decelerate quicker,
but then you move into the realms
of what can the human body sustain,
and of course, fighter jets and so on
will experience G loading of much higher than 3g,
but that's for a relatively short amount of time.
- So Bloodhound might be accelerating
as fast as a car can safely accelerate,
and if it doesn't have the space to reach its top speed,
they've gotta find a new spot.
Literally the land speed record is determined by the earth.
That's the limiting factor.
The initial goal when we set out on all of this
over a decade ago, the design brief
was what does a 1000 mile per hour car look like?
You know, we still don't know
in reality if that is possible,
but we believe in principle Bloodhound has the potential
to go at that sort of speed.
- But will it?
I mean, I don't know, I don't think so.
I'm sure that the Bloodhound team
they're gonna get close to it.
I really hope they do.
Big thanks to Dr. Ben Evans
for taking the time to speak with us.
Maybe we'll put up an extended cut of that interview
for all of our Donut Underground followers.
By the way if you're interested
in where we got our liquid horse juice,
I followed a horse around for a long time.
Until next week.
Bye for now.
(upbeat music)