Original subtitles

In this wall -shaking episode of MythBusters, That's the sound!

we're taking combustion and propulsion to

their unnatural limits.

Can a well -aimed, high -pressure air tank really be a lethal missile?

Could two compressed air cylinders power the world's fastest speedboat?

Remember, Jamie, experiments like this are 90 % mental.

And can an engine fueled by gunpowder do anything but blow itself to pieces?

It's fast.

It's furious.

It was the lard that did it. And it's firing on all cylinders.

Who are the Mythbusters?

Adam Savage.

And Jamie Heineman.

This is going to kill you.

Between them, more than 30 years of special effects experience.

That's what I'm talking about!

Joining them, Tori Bellacci.

Very excited about this.

Cary Byron. Look, he cracked into his skull.

And Grant Imahara.

Don't say anything.

They don't just tell the myth.

They put them to the test.

As Adam loves to demonstrate, there's all sorts of interesting ways to injure

yourself on the job.

It seems danger is everywhere, but nothing on the workshop floor has quite

the deadly potential.

of a compressed gas cylinder accidentally snap the valve and any tank

transforms into a massive rocket with no flight plan now that's a fact but

what's the myth well we touched upon a little during shark

week but i don't think we finished it i remember that tank yeah compressed air

cylinders and there are no end to the stories that people tell about the kind

damage that they can do well this one just made a Really big boom, but you're

talking about where they take off like a rocket and go through a concrete wall,

right? Exactly, and that is precisely the myth that we'll be testing.

Adam and Jamie have some experience to draw on. Back in their JAWS special,

blew a scuba tank with a wad of C4 explosive.

Then shot another tank with a high -powered rifle. It didn't blow up, but

sure went off.

And if a cylinder rocket can bend solid steel, what's it going to do to a

concrete wall?

As far as I'm concerned, there really is only one way to test this thing.

Well, yeah, we have to fire it at a cinder block wall. So we're going to

selection of air cylinders and some regulators on them. We're going to need

cinder block wall to fire them into and some kind of method for...

catastrophically taken that regulator right off. And also, we have to figure

how to make sure it actually hits the wall. I mean, what if this thing just

of goes like that?

I think I want to be outside the building that we're testing this inside

Yep. To test the MIF, they'll need to aim the cylinder like a missile, devise

some way to sever the valve in a split second, and build a wall to aim at.

They'll have to start work on the wall first.

So Jamie's assistants, Terry and Tyler, get commissioned as Mythbuster Masons.

So I'm going to set you up, and it's going to be in your hands to make sure

all happens. So don't screw up.

I'll kick your butt.

Walls are useful for all sorts of things, like holding up the roof.

So punching a high -speed hole through a supporting wall might not be such a

good idea.

This freestanding barricade won't be pretty, but it will be, well, great.

Meantime, Adam is checking the myth with a man whose whole working life has been

spent under extreme pressure.

George Ratterman supplies valves and cylinders across the USA.

And like most of us, he's heard all of those explosive stories secondhand.

The first thing we've heard is that if you knock off the valve to a cylinder,

they can fly right through a brick wall.

Yeah, you know, that is the myth. I've heard that from a number of people. In

most cases, you ask them a few more questions, you find out they actually

weren't there.

I think somebody else told them. And most of the time what the story is, it

would take off and it would usually go through a cinder brick wall, disappear,

go out in the field, or else possibly be found, you know, through a couple more

fences or something.

We want to build this rig that shears the valve right off of this. And the

test rig is a large weight in a guided tube that comes down right on top of the

cylinder and knocks it right off. Do you think that's going to work?

I don't know if that's going to work. I would be concerned that you're going to

end up with an uneven break.

into only a partial break, and that's when you're really going to get a

effect of the vessel.

And remember, we're talking an ankle -smashing 140 -pound steel cylinder.

Even a partial shear could send this thing ballistic.

It might also start spinning erratically, which Jamie calls rat

To ensure that doesn't happen, the tank needs a long, sturdy guide rail to

guarantee it takes off in a straight line.

I've got to build a rig that does a couple of different things. The first

is that it has to hold this tank steady in such a place that we can drop a heavy

weight on the valve and knock it off. The second thing is that same holder is

going to guide it as it takes off so that once it gets going, it's aimed in a

certain direction and it'll hit the wall at speed, we hope.

Good. It looks like it fits fine.

To sever the valve, he's fitting a hinged 10 -foot tube to drop a 40 -pound

steel bar bang on the nozzle.

Adams borrowed some T -size tanks from George, so all they need now is a good,

solid target.

I think we got everything.

All right. Well, get out there and try and blow one of these cylinders through

the wall.

This military bunker is the perfect place to test what we all hope will be

world's first and most destructive land torpedo.

Seems Terry and Tyler did a first -rate job.

It works for me.

I think this will do just fine.

Yeah, that seems nice and solid. It's not quite as big as the side of a barn,

but the question remains.

can the cylinder actually hit it? So I'm thinking that when we set up the rig

over by the door, we want to make sure those doors are as close as we can get

them. Okay, well, they are, in theory, rockets, so we should be careful with

them. Now, careful is a word Adam sometimes has trouble hearing.

Now we do the Cirque du Sauvage, right?

Okay. Welcome to Cirque du Sauvage, a one -time -only performance.

That is the power of the mind.

Now to test the power of a 2600 PSI air cylinder and see if it can shatter a

solid brick wall.

I don't mind fingers on a chalkboard, but that's messed up.

To help the rocket on its way, Myth Turn Jess gets to grips with the lard.

Trust Jamie to always have a bucket or two on hand.

It's cheap.

It's smelly, and it's a great way to reduce friction.

It's important to be judicious about your lard distribution, Jeff. The rig is

greased and ready, but will the steel bar have enough momentum to break the

nozzle? This is a two -by -two -inch solid steel bar, and it weighs,

I think, officially a heck of a lot.

That's 40 pounds dropped from a height of 10 feet. It's a classic case of a

square peg in a round hole, and that surely deserves a test run. Piece of a

brick right there. All right. That'll keep the end of our piece of steel from

getting too damaged.

Three, two, one.

Oh, yeah.

That looked pretty serious.

If a 40 -pound bar can do this.

Just imagine what a 140 -pound gas tank could do. If all goes to plan, it's

looking curtains for our wall.

Shooting the scuba tank with a 30 -06, that was awesome.

And I have never felt like we were totally done with that until 10 minutes

now. So Adam's after some closure.

And that opens up a world of possibilities.

Now, here's a motor myth that's way overdue for testing. In fact, it's a

blast from the past.

Most modern engines run on gasoline, but it wasn't always the fuel of choice.

Some mechanical pioneers favored a more explosive kind of combustion.

Trying to test the claim that you can run an engine using only gunpowder.

easy enough.

Get an engine, add black powder, ignite.

Hang on a minute.

There have been a lot of people that have tried this through the ages. Maybe

should try a few of their experiments just to see if we can learn from their

mistakes.

Finally, we get to learn from somebody else's mistakes.

Now, common sense tells us the words engine and gunpowder shouldn't even be

in the same sentence.

But the respected men of science who designed our three test engines clearly

thought otherwise.

And Torrey's not going to learn from anyone's mistakes, because as far as we

know, not one of these engines was ever actually built.

The gunpowder fuel they plan to use is often called black powder. It's a

volatile mix of sulfur, saltpeter, and charcoal.

But before the team even thinks about putting this lethal compound in an

it's worth finding out if it really has the kick needed to push a piston.

Well, we think there could be some really good reasons why you'd want to

black powder in an engine. To demonstrate that, we're going to do a

between black powder and gasoline.

For this first experiment, they custom build a super -sized piston to test the

comparative grunt of gasoline and gunpowder.

To check that the feel works, they need an air pressure test.

And Carrie can't resist going along for the ride.

Three, two, one.

Well, the piston worked.

Operations move out to the car park and into the blast chamber.

That's an indication of how much faith they have in the black powder.

Black powder comes with its own oxidizer. So unlike gasoline, which you

inject a certain amount of air to get it to combust, black powder is ready to go

all the time.

Finding which fuel produces more energy is easy enough to measure.

A magnet sitting on top of the piston should stick to this metal scale, just

where the piston hits the top of its stroke.

First, the gasoline.

Then a propane flame to vaporize it.

Gas, piston, three, two, one.

The gasoline -powered piston has made its mark. No, it couldn't have gone up

there. So it accelerated it all the way up here.

So will the black powder measure up?

Grant's quietly confident.

Our research indicates that black powder has a lot more energy density.

It's measured in grains, which comes from the old Troy system of weight.

One grain is roughly equal to 1 500th of an ounce.

So you're using 20 grains again?

You got it.

They wait for the flame to ignite the powder.

Oh, there we go. Wow. Perfect.

They don't call it gunpowder for nothing.

Wow, shot the magnet off the scale.

This is where the gasoline magnet got shot to.

And there is where the black powder magnet got shot to. Well, that's fairly

conclusive.

Black powder does have more energy density than regular gasoline, meaning

need less of it to get the same amount of power. So it is a sound concept.

But what happens when a sound concept meets an unsound engine?

There's still three combustible contraptions to put to the test.

High -pressure gas cylinders have been around for 100 years, and legends of

their destructive potential have been around for 99.

But could a ruptured tank really burrow through a brick wall?

Back at the bunker, Adam and Jamie are about to find out.

All right, I'm arming the rig.

Arming the rig means unscrewing the protective cap.

All that remains is to pull the string that releases the weight. That hopefully

guillotines the valve.

All right, ladies and gentlemen.

Shearing the compressed air cylinder in 3, 2, 1.

This is close to a worst -case scenario.

As feared, the valve was only partially sheared, so the cylinder went...

Absolutely nowhere.

I'm going to wait however long it takes for it to let go of its air because it's

got a damaged valve and that valve could give any minute and, you know, become a

bullet. It's a very slow leak. So the boys have 45 minutes to stand well back

and revise their plan.

Harry, Grant, and Tori are out to test the myth that an engine can actually run

on gunpowder.

They've shown that black powder definitely has the muscle to move a

This is where the gasoline magnet got shot to.

And there is where the black powder magnet got shot to. Now to build a

kind of proto -engine, specifically designed to run on powder.

It was dreamed up by a Dutchman named Christian Huygens more than 300 years

His blueprint was the very first to feature a piston in a cylinder.

When the black powder ignites, expanding gases are meant to force air out of two

valves, creating a vacuum that sucks the piston down.

It looks pretty easy, pretty straightforward.

Whether or not it's going to work, that's going to be the hard part.

The design is simple and a lot easier to build now than it would have been in

1680.

Total success means getting a near -perfect vacuum.

That's a tricky thing to do with so many moving parts, especially when you have

to drill a hole for the fuse.

Oh, there's a hole down here.

That's not going to give you a vacuum.

That's what the problem is.

We'd have to have that hole there to ignite the black powder.

How are you going to get a vacuum then?

I'm just going from the designs of Huygen.

Should we, like, raise them for the dead?

Well, I finished my Huygens black powder engine.

So now what we're going to do, I drilled a little hole at the bottom cap. We're

going to fill this up with some gunpowder, put a remote fuse in there,

and see if it does, in fact, raise up our weight.

I am not sure if we're going to get a good enough vacuum, and that's the whole

principle that this Huygens engine works on.

But, you know.

There's only one way to find out.

One thing Huygens didn't specify was how much black powder to use.

So they're starting small with five grains.

This weight is attached to the piston. So when the piston is sucked down, the

weight goes up.

Fire in the hole!

In three, two, one.

Okay.

So much for fire in the hole.

the weight hasn't budged in search of more oomph tori trebles the charge to 15

grains here we go in three two one oh god did you feel that the

vacuum it's sucking me in it was huge yeah it sure does suck but the weight

rise a little which means the piston moved slightly in the cylinder dude it

totally pulled it down look at this oh if it were A vacuum it would have been

holding, like you wouldn't have been able to pull it back.

So they up the charge from 15 to 20 grains.

In three, two, one.

It looks like Huygens' original draft is just a little bit too drafty. We have

two things working against us.

Our seal between the piston and the chamber isn't completely airtight. We

as tight as possible, but there's still some leaks.

So we're not getting a true vacuum.

And then also our one -way valve, they're not totally airtight either.

Modern machining gave the engine a better chance of success than Huygens

have imagined.

And it still didn't work.

One black powder engine down, two to go. But there's reason to be hopeful.

Just running through this experiment, though, you can see why people were so

intrigued by the whole black powder engine. It takes so little to create so

force. And soon they'll see if that force makes or breaks an engine George

Cayley had high hopes for.

Adam and Jamie are trying to figure out what went wrong with their first attempt

to blast an air cylinder through a brick wall.

I can still see it.

Yeah, it hasn't moved.

In best MythBusters tradition, they decide to tinker with just about

An extra 30 pounds of lead is shaved down for the trigger.

Pencil rods are added to help guide the weight.

And never underestimate the benefits of extra lard.

And third joke here.

So this second time around, we've added more weight. We've lubricated the whole

weight system so that it'll be...

more slippery when it goes down. And then probably most importantly of all,

we've moved the valve placement slightly so that the weight when it hits it will

hit right on the very tip of the valve.

And that'll provide the most leverage and hopefully snap it more readily.

Calm, steady words from a man who's hoping to launch a gas cylinder into the

next county. Here we go, steering the regulator off a tank.

Attempt number two in five.

Four. Cross your fingers. Three. Two.

One.

Yeah!

That's the sound!

That is a lovely, lovely sound.

The valve has sheared clean off, and that's a very good sign.

It looks like the cylinder flew straight and true.

But did it have enough thrust to crack the wall?

Oh, God.

It was the lard that did it.

At 40 miles per hour, the air tank turned the cinder block to cinders. It

put a fair dent in the wall six feet behind it.

No way!

I mean, it didn't go all the way through, but it went through this one,

working its way through that one.

I was ready to see that this is not possible. I was totally expecting it not

actually work, because it's one of those apocryphal tales, and everyone we

talked to had heard the story, but no one knew anybody that it happened to.

You know, this was an optimum situation for this tank.

What this tank did is as good as it gets.

My favorite thing is the perfect roundness of the top of this hole. It

this entire wall back.

Although the cylinder was deliberately aimed, you couldn't

ask for a more convincing result.

So let's call this myth totally and spectacularly confirmed.

But the Mythbusters can't just leave it there. They plan to double the stakes

and push this explosive experiment to its limit.

Cary Grant and Tory are hell -bent on proving an engine can run on gunpowder.

Fire in the hole!

But could this really be a viable alternative to gasoline they've already

tested and been disappointed by a black powder engine designed way back in the

17th century.

So it's back to the drawing board.

You know what our problem is going to be is getting an engine to start and

sustain itself using black powder.

I do remember coming across a black powder engine.

I think it was Sir George Cayley, the guy who did the first glider, and he was

the father of modern aerodynamics.

He had wanted to make a flying machine that was completely powered by a black

powder engine that reloaded itself.

So, I mean, I bet we could find some plans floating around the file

Thanks to the graphics department, we can see it would have looked something

like this.

When the powder ignites, the air expands into the reservoir cylinder, pushing

the piston up.

Then at the top of the stroke, a bowstring pushes the piston back down.

On each rise, the piston turns a stopcock, which funnels more gunpowder

system. And so the cycle is repeated. And repetition is the key to a working

engine. Maybe the gunpowder engine could be making a big comeback here.

We could get rid of all of our fossil fuel dependence.

Knocking up a 19th century engine poses no problems.

And luckily, they even have a bow handy, a leftover from the split arrow myth.

They string it over the piston, and pretty soon, Cayley's drawing comes to

The clever part is that it reloads the gunpowder every single time.

Hopefully. So that this fits and will keep going and we've created an engine.

With the engines ready to go, Carrie decides on a quick test.

We need to know how fast we need to get out of the container. We need to know

the time between ignition and the engine running.

In other words, how fast will Tari have to run once he's lit the flame? He kicks

off with just five grains of gunpowder.

This amount of gunpowder is going to force the cylinder up.

Plus the 50 pounds of pressure that the bow is putting on it.

I don't think it's going to happen.

And for 40 seconds, it looks like it won't. Why?

They wait.

And they wait.

Well, I think we have sufficient time to get out of there.

Okay.

Nice. Look at the smoke range.

Yeah, let's do it again.

They reset for another test, but Tori's bent on mischief.

Unknown to the others.

He's added way more powder than he was meant to.

Three, two, one.

Is this the combustible black powder?

How much was in there? I put in too much. Talk about a plan backfiring.

Carrie's going off as well.

I'm putting my foot down. You are no longer in charge of handling any of the

black powder. Why?

Because you didn't tell us that you put in 15 grains and I wasn't wearing my ear

protection. I'm going to kick your ass if you ever do it again. Now that the

smoke's cleared on that little incident, the guys know that come the test,

they'll have plenty of time to get out of the firing line.

Well, all we're looking for to prove the concept is to have one ignition and

then have that reset.

and do a second ignition.

If we can do that, we've proved Cayley's idea.

I think our worst -case scenario and our best -case scenario are generally the

same thing. A big explosion, a lot of screaming, some fun, hopefully safe fun.

I'm feeling supremely confident, actually, in this device.

I think it's at least going to give us two cycles. I think it's probably going

to give us more, depending on how much gunpowder we put in the reservoir.

They fuel up. Or should that be load up? Remember, you don't want to put more

than you need.

Thank you, Tori. This one's going in.

That's five grains of black powder. Will it be enough to get this engine turning

over? All right, we're lit.

Whoa!

Okay, sort of worked. The expanding gases did push the piston up, and the

bowstring did reset the piston. But the reload mechanism didn't. Well, reload.

Still, it's not like the whole thing's gone up in smoke.

It actually worked, and it didn't fall apart. We had one good stroke, but

unfortunately, our hopper seemed to have shot or knocked out all of our

gunpowder, which blacked when it hit the propane.

The answer? Some aluminum foil over the hopper, which should keep the powder in

place.

Take two. Remember, for proof of concept, the engine has to complete at

two cycles.

Once again, the engine only manages a single stroke.

The problem this time is Carrie's reload mechanism can't keep up.

It's happening too fast to dump the black powder in there. It's not going to

just fall into the little groove really, really quickly if it's just there.

Basically, the action is so fast and violent, it doesn't have time to reload.

That means a black mark for another black powder engine.

Adam and Jamie have already proved the power of a well -aimed T -type air tank.

Cylinder one, wall nothing.

It was almost too easy.

I'm now wondering what we do to harm this kind of power.

Why don't we put a saddle on it and take a ride? What do you think?

No, no, no, a speedboat. Let's put a couple of them in a boat and see how

we can go on the water.

That might be a little technical. In place of a normal engine, they plan to

two monster air tanks with 5 ,200 pounds of pent -up pressure between them.

Adam has to build a throttle that releases both valves at precisely the

time. And Jamie needs to buy a boat that won't blow the budget.

This one's a lean 16 -footer designed for high speed.

It's also missing a motor, a dashboard, and a steering wheel. So I assume it

floats, right? I've never had it in the water, so you're going to have to go on

faith. So there you have it, a boat that never left the driveway.

At least there should be no sentimental attachment.

You've seen the show before, right? Oh, yes, big fan.

So you're aware that there's a strong likelihood that we're going to do

something horrible to your boat?

Yeah, yeah.

Do you have any kind of, like, remorse or anything about seeing your boat, you

know, potentially turned into shrapnel?

We're sort of expecting that that could happen to it. Selling your boat to the

Mythbusters must feel something like selling your horse to the glue factory.

Still, the deal is struck, and it smiles all around.

Of course, you know that the two happiest days of a boat owner's life are

day that you buy a boat and the day that you sell it. I think this is one of

those days.

And it's one of those days for Jamie, too.

There's no feeling quite so rewarding as carefully customizing your very own

speedboat. Oh, it brightens my mood when we break out the sledgehammer. The team

has just one day to get through a titanic amount of work.

What I'm going to do is take this pipe and...

kind of bolted on a swivel thing on the transom of the boat.

And I'd also have to build a kind of a wooden paddle thingy to actually go in

the water and guide it. Ah, yes, that would be called a rudder. And they'll

to attach it to a kind of round wheelie watch that's up near the pointy end of

the boat.

So Adam cuts, belts in, then spot welds the paddle thingy.

They've decided to mount the seat between the two tanks.

And for some obscure nautical reason, they're using Adam's posterior as a

yardstick.

The minimum is going to be like about 15 inches.

Wait, you're going too far. I'm going inside of my hands.

Yeah, you're squeezing it.

That's 14 inches. Why Jamie needs an accurate measure of Adam's buttocks is

anyone's guess.

But it is time they both got the lead out.

So, with a little elbow grease...

Then some screws and a strong epoxy glue for the baseboard. Our dual inboard

rockets are finally hauled on board.

And strapped down tight.

Dude, I love it.

I'm starting to get excited.

And although Adam's backside set the standard, it's Jamie who'll be steering

ship.

Go ahead and have a seat.

To ensure these two cylinders fire at precisely the same time, the factory

-fitted nozzles are being replaced with ball valves.

They'll both be hooked up to a single linkage, devised and built by our very

Adam Savage.

We'll have a lever here or here, and we will activate that lever. It'll open up

the valve, releasing the pressure, and hopefully what we'll see out of this

is what we saw out of our tank in the concrete wall experiment.

Two hours later, and that scratch -built throttle is up and running. It's

simple, it's purely mechanical, and it works.

But there's still one design feature worth considering.

I also want to make some fins.

I know it's dumb, but it'll look great if we have, you know, no one will

it for anything but a Mythbusters boat.

I'm thinking of a couple fins shaped like flame. I have a better idea. How

just square ones that look fighter plane -like? They'll be like one in each

corner and a V shape.

We can just cut them on the table saw. It'll be really fast.

What do you think?

So far as Adam's concerned, nothing says devastating speed like a pair of flame

-shaped plywood tail fins.

Painting.

From the cut to the color, these are all vintage hot rod class.

But this time, Jamie's calling the shot.

He might not know art, but he knows what he hates.

Tell me you're sorry that I wasted my time.

I'm sorry you wasted your time, and I appreciate your allowing me to make

something a little more subtle.

Okay. Thank you.

It's a trifling tiff that shows Jamie's really taken the project to heart.

He's proud of the boat. He's excited about it, as am I. I mean, it looks

cool. And he wants whatever modifications we make to reflect that

make a joke about it.

But style isn't the big issue here.

It's all about the hardware. This is a business end.

A half -inch bore, 2 ,600 PSI coming through each one. It was enough to drive

single 150 -pound tank through a wall and halfway through a second wall. The

question is, is two of them enough to drive a rocket boat?

There's only one way to get an answer.

Dress Jamie up like a walrus. I want you to be the boat. I want you to exist as

one with the water.

And hope he floats.

Our black -powdered dynamos have already brought two antique engines to life.

Then watch them die a sad death.

So that leaves us where?

Back at square one.

Not actually. Since we've been dealing with an internal combustion engine, I

thinking, hey, let's try an external combustion engine. Let's get rid of the

piston, and we'll make like a water wheel.

Tari's thinking of Thomas Paine's 19th century radial engine.

which does work much like a water wheel.

But what if we replaced water power with the grunt of gunpowder?

Okay, well, well, Tori works in the opposite direction of engineering

How about you and I go find ourselves an internal combustion engine, something

that's already a successful engine, and try to adapt it to black powder?

Well, it should work in theory.

Sounds good.

While Torrey starts work on his black powder wheel, Grant and Carrie will take

regular four -stroke engine, replace gas with gunpowder, and try to rev it up.

Before they do that, one or two questions need answering.

The first test that we have to perform is to see whether this spark plug can

ignite the black powder.

Using a drill, Grant will run the engine manually to see if the spark plug's

spark is enough to ignite five grains of gunpowder.

Fire in the hole!

Hopefully. Here we go.

Woo! Yeah!

Woo! It worked!

Okay, good.

Nice! Good. Great.

Okay, so they know a spark plug can set off the powder. The big question is, how

will they get the gunpowder into the engine?

An engine normally works by sucking vaporized gasoline into the cylinder.

But the grains of black powder are too big to be sucked, so Carrie plans to

break them down.

This is a black powder tumbler. This is how you can make black powder. You can

put the three constituents into here, roll them, and make a fine powder.

And the longer you roll it, the finer it gets.

We thought maybe if we could make it a nice fine powder, something more dusty

that could kind of just float in the air, maybe then we could have it stuck

the intake.

They put 100 grains in the tumbler.

And voila.

And set it at tumbling. It takes a little while, so let's see how the

progressing.

For his Thomas Paine -designed radial engine, Tari's lined the perimeter of a

wagon wheel with metal cup.

The expanding gases from the powder, ignited in a separate chamber, will

into the cups, causing the wheel to spin.

Dude, it's like an 1860s circular saw. To keep his engine running, Tario's also

rigged a hopper to reload the powder after each blast.

Right now I have the black powder dispenser rigged up to the rig here, and

have this little piece of steel. As it rotates, it will push the...

The button in and releasing an amount of black powder.

To test the wheel, Grant blasts compressed air through the system.

That looks pretty good, man. Yeah. How much PSI was that? That's just 125 PSI.

Black powder is going to be tens of thousands.

With those kinds of forces in play, they set up Torrey's wheel of misfortune in

the blast chamber. In the first test... they'll start slow with just 15 grains

of black powder per cycle.

Initiating glow plug.

Okay, and not enough pressure to get the wheel going.

And even with 70 grains, Wow.

Payne's wheel of steel just ain't spinning.

Before Torrey slides into depression, he wants to improve the compression.

And try again.

So the only modification that I did is I cut off this big chamber, which is way

too big. We weren't getting the compression that we need. I welded on a

tube. Hopefully it'll give us more compression. It's more like a shotgun.

hopefully we'll get this wheel spinning.

All right, here we go in three, two, one.

This is taking too long.

Nope, 70 grains wasn't too much. The whole thing backfired. Gases from the

explosion were forced back up into the hopper, which set off all the black

powder. And still, the wheel didn't turn.

Oh, no way!

Don't even go in yet.

They've blown the hopper off, so this experiment is pretty much over.

Not only did it not work, now we don't have a way to...

continue to introduce black powder into our engine.

Adjusting the charge and the timing might have helped, but the gravity -fed

reload system looks doomed to failure every time.

Payne's instructions were followed precisely, so it's safe to say that like

other two engines that came before, it just doesn't work.

But Grant, Harry, and Tori have one last hope. They'll put gunpowder in a

lawnmower engine to see if that cuts the mustard.

Grant's mental machinery has already been crunching the gear, pondering a way

getting the black powder into the engine.

And he's devised an ingenious fuel injection system.

What this is is an air eraser, basically a miniature sandblaster. Black powder

goes inside of this reservoir, and compressed air goes in here.

You set this to wherever you want it to be, and a constant stream of black

powder should be shooting out of here.

Out in the blast chamber, they set up for the test.

The air eraser is rigged up to squirt the black powder directly into the

combustion chamber.

Anybody else as excited about this as I am?

Once again, Grant uses the drill to turn the engine over. Sort of a crude

version of the starter motor you'd find in your car.

Fire in the hole!

A second or two later, the fuel should kick in. In this case, the powder.

We're anticipating a throaty throb and a nice dark puff of exhaust gas.

Well, that didn't quite work.

And when Grant takes a peek inside the casing, he sees why.

Is it all gooped up from the oil?

Yeah, there's quite a bit that's actually kind of clumped in a wet

They're left with an engine enigma. Our fuel needs to be dry to ignite, and as

it comes up into the cylinder, the oil mixes with the black powder and makes a

gooey slurry that we cannot ignite.

They've got one last shot. They'll strip down the engine, drain all the oil, and

see if the injected powder will ignite before the engine seizes up.

There's a lot of oil in there.

And Torrey thinks their chances might be better if they replace the spark plug,

which fires intermittently, with this little device.

So what I did is I made this little glow plug, and all it is is a little coil of

wire. We're going to attach it to a battery. It'll glow red hot, and that'll

a constant source of heat to ignite the black powder every time it enters the

chamber. He's a bright spark, isn't he?

Right. It's the moment of truth.

Will this four -stroke engine go on gunpowder, or is it the end of the road

this myth?

Gentlemen, start your engines.

Blow plug.

Black powder.

Nothing. Zilt, zip, and buff kit. In desperation, they put five grains of

gunpowder directly into the cylinder and try again. Three, two.

One. We've got a fire. Come on.

Baby.

We did get one push. We got one charge. We got one fire. Yeah, we got one

ignition.

Even a working engine won't work with gunpowder. And for that, we should

probably all be grateful.

Do we really have to talk about this one? No.

But we will anyway.

But you can see why, over the ages, it was so tempting to use black powder.

got such high energy density.

It would make a good fuel.

But the stumbling block is getting the black powder into the piston and

igniting it. Not to mention that these are dangerous.

So you ready to wrap this one up?

Yep. Claim it.

Busted. Easy.

Busted. Busted.

So just how much fun can one man have in a souped -up speedboat? By the looks of

it, plenty.

Adam and Jamie are ready to live out the ultimate boyhood dream, fitting two

potentially explosive air cylinders to an unsuspecting ski boat, then cutting

loose.

That's what it's going to be like. It's not a fully fledged myth, but after the

success of an air cylinder blasting through a wall, It's impossible to

It's supposedly about taking us all the way to the end of the myth, but come on,

I think we all know that it's an excuse to have some fun with some big, high

-powered rockets.

Step one is getting our stunt skipper installed in his wetsuit without having

blur some parts of your screen.

Step two is filling the cylinders in the boat with compressed air from the

truck.

These tanks are actually filled with geese, and they're complaining.

Was that a joke?

I think that was a joke.

Fascinating.

And step three is seeing if Adam and Jamie can finally float their own boat.

The worst case scenario, I have to say, is that one of the tanks...

blows up, and the shrapnel ends up ripping through Jamie's flesh and

him. So much for the pep talk.

It's a good rule of thumb that support staff should be seen and not heard.

Jamie, so when we release you, we're going to pull off to the right -hand

and you're going to steer to our left.

Okay?

You mean I'm going to steer off to port?

Yes, you're going to steer off to port, you old salt.

And we'll be to the starboard.

What, left and right isn't good enough when there's water around?

There's also plenty of spectators around, so they'll have to be careful.

We've got a tour over here of kids in small boats. We're going to tell you

that tour before we release you.

When all seems safe, the rocket boat is finally cut loose from the mothership.

And remember, they're dealing here with... twice the pressure used earlier

smash a brick wall.

Jamie's ready, and the mechanical throttle is gently nudged forward in the

-ass direction.

Oh,

dear.

Lots of noise and lots of spray, but that brief burst of speed...

clocked in at just over five knots on the speed gun.

And the boat was propelled a mere 120 feet.

Well, that was a whole lot of nothing.

But Adam is more upbeat.

That was excellent.

I mean, it didn't do anything really important, but it was cool looking.

Okay, there's no doubt we've just seen one of the best rooster tails this side

of a barnyard. But let's face facts.

Jamie can probably swim faster than five knots.

The boys have given themselves one more chance to prove the concept, and they're

ready to float some ideas.

We may be able to optimize this a little bit if we choke the outlet down, and

also we're going to try to drop it into the water a little lower, because I'm

not sure the physics on it, but my hunch says that the air pushing more against

the water instead of against just air.

Give us a little more.

It's a bold decision that involves a lightning pit stop and a radical refit

the outlet valves.

The full force of all that compressed air will now be released underwater.

Jamie is also not going to go gingerly with the throttle this time. He is just

going to push it all the way forward on the first go and just expend all the

power trying to get up to speed and stay at a speed.

actually travel more than, you know, 120 feet.

Tanks are refilled and the boat's back in position.

It's now sink or swim.

And Adam has some, well, vaguely helpful words of encouragement.

Remember, Jamie, experiments like this are 90 % mental. I want you to be the

boat. I want you to exist as one with the water.

Think about the boat planning, the physics involved.

Feel them in your body. Are you ready?

What?

I said just go for it.

The rocket boat is unleashed, and it's anchors away.

Let's assume that hysterical laughter is not a good sign. In fact, the boat

traveled only half the distance of its first run.

It was about the same as the other one, wasn't it?

No, it wasn't even close.

As for the speed gun, it was hardly worth installing the battery.

Well, I think that would proverbially be that.

This lavish maritime experiment turned out to be a spectacular failure.

Maybe it's time Jamie invested in a good, reliable outboard.

I don't think he even made it like 60 or 70 feet that time.

I don't know if you can calculate it in miles per hour. It would be more like

miles per day.

So we have to ask ourselves, what's the washout?

So, Jamie, how are we going to wrap this one up? What do you call it?

Well, we did get a tank to blow through a cinder block wall when we knocked the

valve off, so that's confirmed. I mean, there were documented cases as well. And

you can strap some air tanks to a boat and give it a little bit of power,

It's not that practical. It's not real power.

Yeah, we need to go for the hydrogen and light it.

It's another episode.

We've got to let this one go.