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Give us a break. Don't try what you're about to see at home.

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Yeah!

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

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

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

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It's fast. It's furious.

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It was the lard that did it.

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And it's firing on all cylinders.

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Who are the Mythbusters?

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Adam Savage

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and Jamie Heineman.

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This is gonna kill you.

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Between them more than 30 years of special effects experience.

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That's what I'm jogging about.

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Joining them, Tori Velachie.

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Very excited about this.

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Carrie Byron.

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Look, he cracked into his skull.

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And Grant Imahara.

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Don't say anything.

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They don't just tell the myths.

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They put them to the test.

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As Adam loves to demonstrate,

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there's all sorts of interesting ways to injure yourself on the job.

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It seems danger is everywhere.

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But nothing on the workshop floor has quite the deadly potential

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of a compressed gas cylinder.

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Accidentally snap the valve and any tank

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instantly transforms into a massive rocket with no flight plan.

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Now, that's a fact, but what's the myth?

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Well, we touched upon it a little during Shark Week,

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but I don't think we finished it.

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I remember that thing.

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Yeah, compressed air cylinders.

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And there are no end to the stories that people tell

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about the kind of damage that they can do.

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Well, this one just made a really big boom,

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but you're talking about where they take off like a rocket

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and go through a concrete wall, right?

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Exactly.

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And that is precisely the myth that we'll be testing.

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Adam and Jamie have some experience to draw on.

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Back in their jaw special,

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they blew a scuba tank with a wad of C4 explosive.

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Then shot another tank with a high-powered rifle.

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It didn't grow up, but it sure went off.

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And if a cylinder rocket can bend solid steel,

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what's it going to do to a concrete wall?

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As far as I'm concerned,

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there really is only one way to test this thing.

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Well, yeah, we have to fire it at a cinder block wall.

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So we're going to need a selection of air cylinders

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and some regulators on them.

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We're going to need a cinder block wall to fire them into

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and some kind of method for catastrophically taking

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that regulator right off.

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And also we have to figure out how to make sure

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it actually hits the wall.

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I mean, what if this thing just kind of goes...

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I think I want to be outside the building

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that we're testing this inside of.

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To test the myth,

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they'll need to aim the cylinder like a missile,

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devise some way to sever the valve in a split second,

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and build a wall to aim at.

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

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so Jamie's assistants, Terry and Tyler,

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get commissioned as Mythbuster Masons.

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So I'm going to set you up,

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and it's going to be in your hands to make sure it all happens.

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So don't screw up.

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I'll kick your butt.

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Walls are useful for all sorts of things,

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like holding up the roof.

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So punching a high-speed hole through a supporting wall

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might not be such a good idea.

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This freestanding barricade won't be pretty,

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but it will be, well, great.

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Meantime, Adam is checking the myth with a man

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whose whole working life has been spent under extreme pressure.

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George Ratterman supplies valves and cylinders across the USA,

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and like most of us,

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he's heard all of those explosive stories secondhand.

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

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they can fly right through a brick wall.

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Yeah, you know, that is the myth.

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I've heard that from a number of people.

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In most cases, you ask them a few more questions,

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and they actually weren't there.

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I think somebody else told them.

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And most of the time what the story is,

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it would take off and it would usually go through a cinder-brack wall,

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disappear, go out in the field,

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or else possibly be found, you know,

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through a couple more fences or something.

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

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and the first test rig is a large weight in a guided tube

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that comes down right on top of the cylinder and knocks it right off.

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I mean, do you think that's going to work?

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I don't know if that's going to work.

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You're going to have to give and break into only a partial break,

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and that's when you're really going to get a spinning effect of the vessel.

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

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Even a partial shear could send this thing ballistic.

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It might also start spinning erratically, which Jamie calls rat-chasing.

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To ensure that doesn't happen,

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the tank needs a long, sturdy guide rail

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to guarantee it takes off in a straight line.

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I've got a builder rig that does a couple of different things.

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The first thing is that it has to hold this tank steady in such a place

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that we can drop a heavy weight on the valve and knock it off.

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The second thing is that same holder is going to guide it as it takes off

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so that once it gets going, it's aimed in a certain direction,

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

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Good. It looks like it fits fine.

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To sever the valve,

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he's fitting a hinged 10-foot tube to drop a 40-pound steel bar bang on the nozzle.

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Adams borrowed some tea-sized tanks from George,

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so all they need now is a good, solid target.

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I think we got everything.

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All right. Well, let's get out there and try and blow one of these cylinders through the wall.

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

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will be the world's first and most destructive land torpedo.

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Seems Terry and Tyler did a first-rate job.

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It works for me.

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I think this will do just fine.

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Yeah, that seems nice and solid.

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It's not quite as big as the side of a barn,

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but the question remains, can the cylinder actually hit it?

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So I'm thinking that when we set up the rig over by the door,

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we want to make sure those doors are as close as we can get them.

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

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To help the rocket on its way,

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Myth Turn Jess gets to grips with the lard.

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

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

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It's important to be judicious about your lard distribution, Jess.

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The rig is greased and ready,

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but will the steel bar have enough momentum to break the nozzle?

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This is a 2 by 2 inch solid steel bar,

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and it weighs, I think, officially a heck of a lot.

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

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It's a classic case of a square peg in a round hole,

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and that surely deserves a test run.

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Piece of a brick right there that'll keep the end of our piece of steel from getting too damaged.

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Three, two, one.

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Oh, yeah.

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That looks pretty serious.

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If a 40 pound bar can do this,

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just imagine what a 140 pound gas tank could do.

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If all goes to plan, it's looking curtains for our wall.

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Shooting the scuba tank with a 30-odd 6, that was awesome.

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

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until 10 minutes from now.

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Coming up, Carrie Grant and Tori put gasoline and gunpowder to the test

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in a giant homemade cylinder.

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And the boys get ready to bring the house down.

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Shearing the compressed air cylinder in three, two, one.

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

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In fact, it's a classic blast from the past.

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Most modern engines run on gasoline,

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but it wasn't always the fuel of choice.

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Some mechanical pioneers favored a more explosive kind of combustion.

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

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Sounds easy enough. Get an engine, add black powder, ignite.

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Hang on a minute.

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

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Maybe we should try a few of their experiments

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just to see if we can learn from their mistakes.

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

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The common sense tells us the words engine and gunpowder

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shouldn't even be used in the same sentence.

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

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clearly thought otherwise.

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And Tori's not going to learn from anyone's mistakes

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because as far as we know, not one of these engines was ever actually built.

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The gunpowder fuel they plan to use is often called black powder.

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It's a volatile mix of sulfur, salt-peter and charcoal.

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

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

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Well, we think there could be some really good reasons

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why you'd want to use black powder in an engine.

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To demonstrate that, we're going to do a comparison between black powder and gasoline.

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For this first experiment, they custom-built a super-sized piston

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to test the comparative grunt of gasoline and gunpowder.

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

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

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Let me in! Let me in!

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Well, the piston works.

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

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

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Black powder comes with its own oxidizer, so unlike gasoline,

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which you need to inject a certain amount of air to get it to combust,

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black powder is ready to go all the time.

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

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

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just where the piston hits the top of its stroke.

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First, the gasoline.

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Then a propane flame to vaporize it.

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Gas mission in three, two, one.

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Yeah!

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The gasoline-powered piston has made its mark.

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No, it couldn't have gone up there.

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So it accelerated it all the way up here.

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So will the black powder measure up?

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Grants quietly confident.

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

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They wait for the flame to ignite the powder.

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There we go. Perfect.

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They don't call it gunpowder for nothing.

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Wow, it shot the magnet off the scale.

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This is where the gasoline magnet got shot to.

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

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Well, that's fairly conclusive.

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Black powder does have more energy density than regular gasoline,

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meaning you need less of it to get the same amount of power.

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So it is a sound concept.

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

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

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High-pressure gas cylinders have been around for a hundred years,

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and legends of their destructive potential have been around for 99.

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

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

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Alright, I'm arming the rig.

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Arming the rig means unscrewing the protective cap.

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All that remains is to pull the string that releases the weight,

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that hopefully guillotines the valve.

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Alright, ladies and germs,

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shearing the compressed air cylinder in three, two, one.

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This is close to a worst-case scenario.

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As feared, the valve was only partially sheared,

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so the cylinder went absolutely nowhere.

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

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because it's got a damaged valve,

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and that valve could give any minute and, you know, become a bullet.

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It's a very slow leak,

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so the boys have 45 minutes to stand well back

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and then pull the string back.

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They have 45 minutes to stand well back

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and revise their plans.

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After the break, the world's first gunpowder engine is cocked and loaded.

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Fire in the hole!

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Then Jamie and Adam reset for the final countdown.

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Cross your fingers. Three, two, one.

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Carrie Grant and Tori are out to test the myth

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that an engine can actually run on gunpowder.

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

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This is where the gasoline magnet got shot to,

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and there is where the black powder magnet got shot to.

250
00:15:04,000 --> 00:15:07,000
Now to build a primitive kind of proto-engine,

251
00:15:07,000 --> 00:15:10,000
specifically designed to run on powder.

252
00:15:10,000 --> 00:15:16,000
It was dreamed up by a Dutchman named Christian Hoegens more than 300 years ago.

253
00:15:16,000 --> 00:15:21,000
His blueprint was the very first to feature a piston in a cylinder.

254
00:15:21,000 --> 00:15:23,000
When the black powder ignites,

255
00:15:23,000 --> 00:15:27,000
expanding gases are meant to force air out of two valves,

256
00:15:27,000 --> 00:15:30,000
creating a vacuum that sucks the piston down.

257
00:15:30,000 --> 00:15:32,000
It looks pretty easy, pretty straightforward.

258
00:15:32,000 --> 00:15:35,000
Whether or not it's going to work, that's going to be the hard part.

259
00:15:36,000 --> 00:15:39,000
The design is simple, and a lot easier to build now

260
00:15:39,000 --> 00:15:42,000
than it would have been in 1680.

261
00:15:43,000 --> 00:15:47,000
Total success means getting a near-perfect vacuum.

262
00:15:47,000 --> 00:15:50,000
That's a tricky thing to do with so many moving parts,

263
00:15:50,000 --> 00:15:54,000
especially when you have to drill a hole for the fuse.

264
00:15:54,000 --> 00:15:59,000
There's a hole down here. That's not going to give you a vacuum.

265
00:15:59,000 --> 00:16:01,000
That's what the problem is.

266
00:16:01,000 --> 00:16:04,000
We have to have that hole there to ignite the black powder.

267
00:16:04,000 --> 00:16:06,000
How are you going to get a vacuum then?

268
00:16:06,000 --> 00:16:09,000
I'm just going from the designs of Hoegen.

269
00:16:09,000 --> 00:16:11,000
Should we raise them for the dead?

270
00:16:12,000 --> 00:16:16,000
Well, I finished my Hoegen's black powder engine.

271
00:16:16,000 --> 00:16:20,000
Now what we're going to do, I drilled a little hole at the bottom cap.

272
00:16:20,000 --> 00:16:22,000
We're going to fill this up with some gunpowder,

273
00:16:22,000 --> 00:16:25,000
put a remote fuse in there, light it,

274
00:16:25,000 --> 00:16:30,000
and see if it does in fact raise up our weight.

275
00:16:30,000 --> 00:16:36,000
I am not sure if we're going to get a good enough vacuum,

276
00:16:36,000 --> 00:16:40,000
and that's the whole principle that this Hoegen's engine works on.

277
00:16:40,000 --> 00:16:44,000
But, you know, there's only one way to find out.

278
00:16:44,000 --> 00:16:47,000
Here we go in three, two, one.

279
00:16:47,000 --> 00:16:49,000
Oh, God, did you feel that?

280
00:16:49,000 --> 00:16:53,000
The vacuum! It's sucking me in! It was huge!

281
00:16:53,000 --> 00:16:55,000
Yeah, it sure does suck.

282
00:16:55,000 --> 00:16:57,000
But the weight did rise a little,

283
00:16:57,000 --> 00:17:00,000
which means the piston moved slightly in the cylinder.

284
00:17:00,000 --> 00:17:02,000
Dude, it totally pulled it down. Look at this.

285
00:17:02,000 --> 00:17:07,000
Well, if it were a vacuum, it would have been holding like you wouldn't have been able to pull it back.

286
00:17:07,000 --> 00:17:12,000
So they upped the charge from 15 to 20 grains.

287
00:17:12,000 --> 00:17:15,000
In three, two, one.

288
00:17:16,000 --> 00:17:21,000
It looks like Hoegen's original draft is just a little bit too...drafty.

289
00:17:21,000 --> 00:17:23,000
We have two things working against us.

290
00:17:23,000 --> 00:17:27,000
Our seal between the piston and the chamber isn't completely airtight.

291
00:17:27,000 --> 00:17:32,000
We got it as tight as possible, but there's still some leaks, so we're not getting a true vacuum.

292
00:17:32,000 --> 00:17:37,000
And then also our one-way valves. They're not totally airtight either.

293
00:17:37,000 --> 00:17:43,000
Modern machining gave the engine a better chance of success than Hoegen's could have imagined,

294
00:17:43,000 --> 00:17:45,000
and it still didn't work.

295
00:17:45,000 --> 00:17:49,000
One black powder engine down, two to go.

296
00:17:49,000 --> 00:17:51,000
But there's reason to be hopeful.

297
00:17:52,000 --> 00:17:57,000
Just running through this experiment, though, you can see why people were so intrigued by the whole black powder engine.

298
00:17:57,000 --> 00:17:59,000
It takes so little to create so much force.

299
00:17:59,000 --> 00:18:06,000
And soon they'll see if that force makes or breaks an engine George Cayley had high hopes for.

300
00:18:14,000 --> 00:18:20,000
Adam and Janie are trying to figure out what went wrong with their first attempt to blast an air cylinder through a brick wall.

301
00:18:21,000 --> 00:18:23,000
I can still see it.

302
00:18:23,000 --> 00:18:25,000
Yeah, it hasn't moved.

303
00:18:25,000 --> 00:18:30,000
In best misbusters tradition, they decide to tinker with just about everything.

304
00:18:31,000 --> 00:18:34,000
So this second time around we've added more weight.

305
00:18:34,000 --> 00:18:41,000
We've lubricated the whole weight system so that it'll be more slippery when it goes down.

306
00:18:41,000 --> 00:18:47,000
And then probably most importantly though, we've moved the valve placement slightly so that the weight when it hits it

307
00:18:47,000 --> 00:18:50,000
will hit right on the very tip of the valve.

308
00:18:50,000 --> 00:18:54,000
And that'll provide the most leverage and hopefully snap it more readily.

309
00:18:54,000 --> 00:18:59,000
Calm, steady words from a man who's hoping to launch a gas cylinder into the next county.

310
00:18:59,000 --> 00:19:02,000
Here we go. Shearing the regulator off the tank.

311
00:19:02,000 --> 00:19:06,000
Attempt number two and five.

312
00:19:06,000 --> 00:19:08,000
Four, cross your fingers.

313
00:19:08,000 --> 00:19:11,000
Three, two, one.

314
00:19:12,000 --> 00:19:20,000
Yeah! That's the sound!

315
00:19:25,000 --> 00:19:27,000
That is a lovely, lovely sound.

316
00:19:28,000 --> 00:19:32,000
The valve has sheared clean off and that's a very good sign.

317
00:19:32,000 --> 00:19:39,000
It looks like the cylinder flew straight and true, but did it have enough thrust to crack the wall?

318
00:19:42,000 --> 00:19:45,000
Oh my God.

319
00:19:46,000 --> 00:19:49,000
It was the lard that did it.

320
00:19:51,000 --> 00:19:56,000
At 40 miles per hour, the air tank turned the cinder block to cinders.

321
00:19:56,000 --> 00:20:00,000
It even put a fair dent in the wall six feet behind it.

322
00:20:00,000 --> 00:20:07,000
It totally, I mean it didn't go all the way through, but it went through this one and it was going, it's working this way through that one.

323
00:20:07,000 --> 00:20:10,000
I was ready to, I was ready to see this as not possible.

324
00:20:10,000 --> 00:20:18,000
I was totally expecting it not to actually work because it's one of those apocool tales and everyone we talked to had heard the story, but no one knew anybody that it happened to.

325
00:20:18,000 --> 00:20:22,000
You know, this was an optimum situation for this tank.

326
00:20:22,000 --> 00:20:26,000
What this tank did is as good as it gets.

327
00:20:28,000 --> 00:20:32,000
My favorite thing is this perfect roundness of the top of this hole.

328
00:20:32,000 --> 00:20:36,000
It also pushed this entire wall back a half minute.

329
00:20:38,000 --> 00:20:44,000
Although the cylinder was deliberately aimed, you couldn't ask for a more convincing result.

330
00:20:44,000 --> 00:20:49,000
So let's call this myth totally and spectacularly confirmed.

331
00:20:50,000 --> 00:20:53,000
Next up, the gunpowder plot thickens.

332
00:20:55,000 --> 00:20:59,000
And Jamie finds a boat that's fit to run on rocket power.

333
00:21:03,000 --> 00:21:06,000
Give us a break.

334
00:21:06,000 --> 00:21:10,000
Don't try anything you're about to see us do at home.

335
00:21:10,000 --> 00:21:16,000
Cary Grant and Tori are hell bent on proving an engine can run on gunpowder.

336
00:21:16,000 --> 00:21:18,000
Bar in the hole!

337
00:21:18,000 --> 00:21:21,000
But could this really be a viable alternative to gasoline?

338
00:21:21,000 --> 00:21:28,000
They've already built, tested and been disappointed by a black powder engine designed for the first time in a long time.

339
00:21:28,000 --> 00:21:31,000
So it's back to the drawing board.

340
00:21:31,000 --> 00:21:37,000
You know what our problem is going to be is getting an engine to start and sustain itself using black powder.

341
00:21:37,000 --> 00:21:40,000
I do remember coming across a black powder engine.

342
00:21:40,000 --> 00:21:46,000
I think it was Sir George Cayley, the guy who did the first glider and he was the father of modern aerodynamics.

343
00:21:46,000 --> 00:21:53,000
He had wanted to make a flying machine that was completely powered by a black powder engine that reloaded its engine.

344
00:21:53,000 --> 00:21:57,000
So I mean, I bet we could find some plans floating around the files somewhere.

345
00:21:57,000 --> 00:22:02,000
Thanks to the graphics department, we can see it would have looked something like this.

346
00:22:02,000 --> 00:22:08,000
When the powder ignites, the air expands into the reservoir cylinder, pushing the piston up.

347
00:22:08,000 --> 00:22:13,000
Then at the top of the stroke, a bone string pushes the piston back down.

348
00:22:13,000 --> 00:22:19,000
On each rise, the piston turns a stopcock, which funnels more gas than the piston.

349
00:22:19,000 --> 00:22:25,000
On each rise, the piston turns a stopcock, which funnels more gunpowder into the system.

350
00:22:25,000 --> 00:22:27,000
And so the cycle is repeated.

351
00:22:27,000 --> 00:22:31,000
And repetition is the key to a working engine.

352
00:22:31,000 --> 00:22:35,000
Maybe the gunpowder engine could be making a big comeback here.

353
00:22:35,000 --> 00:22:40,000
We could get rid of all of our fossil fuel dependence.

354
00:22:40,000 --> 00:22:45,000
Knocking up a 19th century engine poses no problems.

355
00:22:46,000 --> 00:22:53,000
And luckily, they even have a bow handy, a leftover from the split-arrow myth.

356
00:22:53,000 --> 00:22:59,000
They string it over the piston, and pretty soon, Kaylee's drawing comes to life.

357
00:22:59,000 --> 00:23:08,000
The clever part is that it reloads the gunpowder every single time, hopefully, so that this piston will keep going and we've created an engine.

358
00:23:08,000 --> 00:23:14,000
Big explosion, a lot of screaming, some fun. Hopefully safe, fun.

359
00:23:14,000 --> 00:23:17,000
I'm feeling supremely confident, actually, in this device.

360
00:23:17,000 --> 00:23:23,000
I think it's at least going to give us two cycles. It's probably going to give us more, depending on how much gunpowder we put in the reservoir.

361
00:23:23,000 --> 00:23:26,000
They fuel up, or should that be load up?

362
00:23:26,000 --> 00:23:28,000
Remember, you don't want to put more than you need.

363
00:23:28,000 --> 00:23:30,000
Thank you, Tori.

364
00:23:30,000 --> 00:23:31,000
There's one going in.

365
00:23:31,000 --> 00:23:36,000
That's five grains of black powder. Will it be enough to get this engine turning over?

366
00:23:36,000 --> 00:23:37,000
Move it.

367
00:23:37,000 --> 00:23:38,000
Alright, we're lit.

368
00:23:44,000 --> 00:23:52,000
Okay, it sort of worked. The expanding gases did push the piston up, and the bow string did reset the pistons.

369
00:23:52,000 --> 00:23:59,000
But the reload mechanism didn't? Well, reload. Still, it's not like the whole thing's gone up in smoke.

370
00:23:59,000 --> 00:24:10,000
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 flashed when it hit the propane.

371
00:24:10,000 --> 00:24:15,000
The answer? Some aluminum foil over the hopper, which should keep the powder in place.

372
00:24:15,000 --> 00:24:17,000
Take two.

373
00:24:17,000 --> 00:24:22,000
Remember, for proof of concept, the engine has to complete at least two cycles.

374
00:24:25,000 --> 00:24:34,000
Once again, the engine only manages a single stroke. The problem this time is Carrie's reload mechanism can't keep up.

375
00:24:34,000 --> 00:24:37,000
It's happening too fast to dump the black powder in there.

376
00:24:37,000 --> 00:24:41,000
It's not going to just fall into the little groove really, really quickly if it's just a...

377
00:24:41,000 --> 00:24:47,000
Basically, the action is so fast and violent, it doesn't have time to reload.

378
00:24:47,000 --> 00:24:52,000
That means a black mark for another black powder engine.

379
00:24:56,000 --> 00:25:01,000
Adam and Jamie have already proved the power of a well-aimed T-type air tank.

380
00:25:01,000 --> 00:25:06,000
It was a cylinder one, wall, nothing. It was almost too easy.

381
00:25:06,000 --> 00:25:10,000
I'm now wondering what we do to harness this kind of power.

382
00:25:10,000 --> 00:25:13,000
Why don't we put a saddle on it and take a ride? What do you think?

383
00:25:13,000 --> 00:25:18,000
No, no, no. A speedboat. Let's put a couple of them in a boat and see how fast we can go on the water.

384
00:25:18,000 --> 00:25:20,000
That might be a little safer.

385
00:25:20,000 --> 00:25:29,000
In place of a normal engine, they plan to fit two monster air tanks with 5,200 pounds of pent-up pressure between them.

386
00:25:29,000 --> 00:25:34,000
Adam has to build a throttle that releases both valves at precisely the same time.

387
00:25:34,000 --> 00:25:39,000
And Jamie needs to buy a boat that won't blow the budget.

388
00:25:39,000 --> 00:25:43,000
This one's a lean 16-footer, designed for high speed.

389
00:25:43,000 --> 00:25:48,000
It's also missing a motor, a dashboard, and a steering wheel.

390
00:25:48,000 --> 00:25:50,000
So I assume it floats, right?

391
00:25:50,000 --> 00:25:53,000
I've never had it in the water, so you're going to have to go on faith.

392
00:25:53,000 --> 00:25:56,000
So there you have it, a boat that never left the driveway.

393
00:25:56,000 --> 00:25:59,000
At least there should be no sentimental attachment.

394
00:25:59,000 --> 00:26:01,000
You've seen the show before, right?

395
00:26:01,000 --> 00:26:02,000
Oh yes, big fans.

396
00:26:02,000 --> 00:26:07,000
So you're aware that there's a strong likelihood that we're going to do something horrible to your boat?

397
00:26:07,000 --> 00:26:09,000
Yes, yeah.

398
00:26:09,000 --> 00:26:17,000
You have any kind of remorse or anything about seeing your boat potentially turned into shrapnel?

399
00:26:17,000 --> 00:26:20,000
We were sort of expecting it, that that could happen to it.

400
00:26:20,000 --> 00:26:26,000
Selling your boat to the Mythbusters must feel something like selling your horse to the Glue Factory.

401
00:26:26,000 --> 00:26:29,000
Still, the deal is struck and it smiles all around.

402
00:26:29,000 --> 00:26:32,000
Of course you know that the two happiest days of a boat are in life.

403
00:26:32,000 --> 00:26:35,000
The day that you buy a boat, the day that you sell it.

404
00:26:35,000 --> 00:26:38,000
I think this is one of those days.

405
00:26:38,000 --> 00:26:41,000
And it's one of those days for Jamie too.

406
00:26:41,000 --> 00:26:48,000
There's no feeling quite so rewarding as carefully customizing your very own speed boat.

407
00:26:48,000 --> 00:26:52,000
It always brightens my mood when we get to break out the sledgehammer.

408
00:26:52,000 --> 00:26:56,000
The team has just one day to get through a titanic amount of work.

409
00:26:56,000 --> 00:27:00,000
They've decided to mount the seat between the two tanks.

410
00:27:00,000 --> 00:27:07,000
And for some obscure nautical reason, they're using Adam's Posterior as a yardstick.

411
00:27:07,000 --> 00:27:11,000
The minimum is going to be like about 15 inches.

412
00:27:11,000 --> 00:27:15,000
Wait, you're going too far. I'm going inside of my hands.

413
00:27:15,000 --> 00:27:18,000
Yeah, you're squeezing and that's 14 inches.

414
00:27:18,000 --> 00:27:23,000
Why Jamie needs an accurate measure of Adam's buttocks is anyone's guess.

415
00:27:23,000 --> 00:27:27,000
But it is time they both got the lead out.

416
00:27:27,000 --> 00:27:33,000
So with a little elbow grease, then some screws and a strong epoxy glue for the baseboard,

417
00:27:33,000 --> 00:27:38,000
our dual inboard rockets are finally hauled on board.

418
00:27:38,000 --> 00:27:42,000
And strapped down tight.

419
00:27:42,000 --> 00:27:46,000
Dude, I love it. I'm starting to get excited.

420
00:27:46,000 --> 00:27:52,000
And although Adam's backside set the standard, it's Jamie who will be steering the ship.

421
00:27:52,000 --> 00:27:58,000
Go ahead and have a seat.

422
00:28:02,000 --> 00:28:06,000
To ensure these two cylinders fire at precisely the same time,

423
00:28:06,000 --> 00:28:10,000
the factory fitted nozzles are being replaced with ball valves.

424
00:28:10,000 --> 00:28:16,000
They'll both be hooked up to a single linkage, devised and built by our very own Adam Savage.

425
00:28:16,000 --> 00:28:20,000
We'll have a lever here or here and we will activate that lever.

426
00:28:20,000 --> 00:28:25,000
It'll open up the valves, releasing the pressure and hopefully what we'll see out of this boat

427
00:28:25,000 --> 00:28:29,000
is what we saw on our tank in the concrete wall experiment.

428
00:28:29,000 --> 00:28:33,000
Two hours later and that scratch build throttle is up and running.

429
00:28:33,000 --> 00:28:37,000
It's simple, it's purely mechanical and it works.

430
00:28:37,000 --> 00:28:42,000
This is the business end. It's a half inch bore, 2600 psi coming through each one.

431
00:28:42,000 --> 00:28:48,000
It was enough to drive a single 150 pound tank through a wall and halfway through a second wall.

432
00:28:48,000 --> 00:28:52,000
The question is, is two of them enough to drive a rocket boat?

433
00:28:52,000 --> 00:28:59,000
Still to come, a paddle wheel outboard that could make or break the myth of black powder engine.

434
00:29:08,000 --> 00:29:15,000
Our black powder dynamos have already brought two antique engines to life.

435
00:29:15,000 --> 00:29:19,000
Then watch them die a sad death.

436
00:29:19,000 --> 00:29:21,000
So that leaves us where?

437
00:29:21,000 --> 00:29:23,000
Back at square one.

438
00:29:23,000 --> 00:29:27,000
Not actually. Since we've been dealing with an internal combustion engine,

439
00:29:27,000 --> 00:29:31,000
I was thinking, hey, let's try an external combustion engine.

440
00:29:31,000 --> 00:29:35,000
Let's get rid of the piston and we'll make like a water wheel.

441
00:29:35,000 --> 00:29:39,000
Tari's thinking of Thomas Paine's 19th century radial engine,

442
00:29:39,000 --> 00:29:42,000
which does work much like a water wheel.

443
00:29:42,000 --> 00:29:47,000
But what if we replaced water power with the grunt of gunpowder?

444
00:29:49,000 --> 00:29:55,000
Okay, well, well, Tari works in the opposite direction of engineering history.

445
00:29:55,000 --> 00:29:59,000
How about you and I go find ourselves an internal combustion engine,

446
00:29:59,000 --> 00:30:03,000
something that's already a successful engine and try to adapt it to black powder?

447
00:30:03,000 --> 00:30:07,000
Well, it should work in theory. Sounds good.

448
00:30:09,000 --> 00:30:12,000
While Tari starts work on his black powder wheel,

449
00:30:12,000 --> 00:30:15,000
Grant and Carrie will take a regular four stroke engine,

450
00:30:15,000 --> 00:30:19,000
replace gas with gunpowder and try to rev it up.

451
00:30:19,000 --> 00:30:23,000
Before they do that, one or two questions need answering.

452
00:30:23,000 --> 00:30:29,000
First test that we have to perform is to see whether this spark plug can ignite the black powder.

453
00:30:29,000 --> 00:30:34,000
Using a drill, Grant will run the engine manually to see if the spark plug spark

454
00:30:34,000 --> 00:30:38,000
is enough to ignite five grains of gunpowder.

455
00:30:39,000 --> 00:30:43,000
Woo! Yeah! It worked!

456
00:30:43,000 --> 00:30:45,000
Okay, good. Nice!

457
00:30:45,000 --> 00:30:46,000
Great.

458
00:30:46,000 --> 00:30:49,000
For his Thomas Paine designed radial engine,

459
00:30:49,000 --> 00:30:53,000
Tari's lined the perimeter of a wagon wheel with metal cups.

460
00:30:53,000 --> 00:30:57,000
The expanding gases from the powder, ignited in a separate chamber,

461
00:30:57,000 --> 00:31:01,000
will channel into the cups, causing the wheel to spin.

462
00:31:01,000 --> 00:31:03,000
Dude, it's like an 1860s circular saw.

463
00:31:03,000 --> 00:31:07,000
To keep his engine running, Tari has also rigged a hopper

464
00:31:07,000 --> 00:31:10,000
to reload the powder after each blast.

465
00:31:10,000 --> 00:31:16,000
Right now I have the black powder dispenser rigged up to the rig here,

466
00:31:16,000 --> 00:31:19,000
and I have this little piece of steel as it rotates.

467
00:31:19,000 --> 00:31:26,000
It will push the button in and releasing an amount of black powder.

468
00:31:26,000 --> 00:31:30,000
To test the wheel, Grant blasts compressed air through the system.

469
00:31:30,000 --> 00:31:32,000
That worked! That looks pretty good, man.

470
00:31:32,000 --> 00:31:35,000
Yeah. How much PSI was that?

471
00:31:35,000 --> 00:31:39,000
It was just 125 PSI. Black powder is going to be tens of thousands.

472
00:31:39,000 --> 00:31:46,000
With those kinds of forces in play, they set up Tari's wheel of misfortune in the blast chamber.

473
00:31:46,000 --> 00:31:52,000
In the first test, they'll start slow, with just 15 grains of black powder per cycle.

474
00:31:52,000 --> 00:31:54,000
Initiating glow plug.

475
00:31:55,000 --> 00:32:01,000
Okay. And not enough pressure to get the wheel going.

476
00:32:01,000 --> 00:32:03,000
And even with 70 grains...

477
00:32:03,000 --> 00:32:05,000
Wow.

478
00:32:05,000 --> 00:32:09,000
...Pain's wheel of steel just ain't spinning.

479
00:32:09,000 --> 00:32:11,000
Ha ha ha ha ha ha!

480
00:32:11,000 --> 00:32:18,000
Before Tari slides into depression, he wants to improve the compression and try again.

481
00:32:18,000 --> 00:32:23,000
So the only modification that I get is I cut off this big chamber, which is way too big.

482
00:32:23,000 --> 00:32:25,000
We weren't getting the compression that we need.

483
00:32:25,000 --> 00:32:29,000
I weld it on a smaller tube. Hopefully it will give us more compression.

484
00:32:29,000 --> 00:32:33,000
It's more like a shotgun. And hopefully we'll get this wheel spinning.

485
00:32:33,000 --> 00:32:37,000
Alright, here we go. In three, two, one.

486
00:32:39,000 --> 00:32:41,000
This is taking too long.

487
00:32:41,000 --> 00:32:44,000
Oh! Ha ha ha ha!

488
00:32:44,000 --> 00:32:47,000
Maybe that was a little too much.

489
00:32:47,000 --> 00:32:50,000
Ha ha ha ha ha ha ha!

490
00:32:50,000 --> 00:32:55,000
Now, 70 grains wasn't too much. The whole thing backfired.

491
00:32:55,000 --> 00:33:00,000
Gasses from the explosion were forced back up into the hopper, which set off all the black powder.

492
00:33:00,000 --> 00:33:03,000
And still, the wheel didn't turn.

493
00:33:03,000 --> 00:33:07,000
Oh no! Wait! Don't keep it going yet.

494
00:33:07,000 --> 00:33:12,000
They've blown the hopper off, so this experiment is pretty much over.

495
00:33:12,000 --> 00:33:18,000
Not only did it not work, now we don't have a way to continue to introduce black powder into our engine.

496
00:33:18,000 --> 00:33:27,000
Adjusting the charge and the timing might have helped, but the gravity-fed reload system looks doomed to failure every time.

497
00:33:27,000 --> 00:33:36,000
Pain's instructions were followed precisely, so it's safe to say that like the other two engines that came before, it just doesn't work.

498
00:33:36,000 --> 00:33:45,000
But Grant, Carrie and Tori have one last hope. They'll put gunpowder in a lawnmower engine to see if that cuts the mustard.

499
00:33:45,000 --> 00:33:52,000
Grant's mental machinery has already been crunching the gears, pondering away of getting the black powder into the engine.

500
00:33:52,000 --> 00:33:56,000
And he's devised an ingenious fuel injection system.

501
00:33:56,000 --> 00:34:01,000
What this is is an air eraser, basically a miniature sand blaster.

502
00:34:01,000 --> 00:34:06,000
Black powder goes inside of this reservoir, and air-compressed air goes in here.

503
00:34:06,000 --> 00:34:12,000
You set this to wherever you want it to be, and a constant stream of black powder should be shooting out of here.

504
00:34:12,000 --> 00:34:15,000
Out in the blast chamber, they set up for the test.

505
00:34:15,000 --> 00:34:21,000
The air eraser is rigged up to squirt the black powder directly into the combustion chamber.

506
00:34:21,000 --> 00:34:24,000
Is anybody else as excited about this as I am?

507
00:34:24,000 --> 00:34:32,000
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.

508
00:34:32,000 --> 00:34:34,000
Fire in the hole!

509
00:34:34,000 --> 00:34:40,000
A second or two later, the fuel should kick in. In this case, the powder.

510
00:34:40,000 --> 00:34:46,000
We're anticipating a throaty throb and a nice dark puff of exhaust gas.

511
00:34:48,000 --> 00:34:51,000
Well, that didn't quite work.

512
00:34:51,000 --> 00:34:55,000
And when Grant takes a peek inside the casing, he sees why.

513
00:34:55,000 --> 00:34:57,000
Is it all gooped up from the oil?

514
00:34:57,000 --> 00:35:03,000
Yeah, there's quite a bit that's actually kind of clumped in a wet puddle.

515
00:35:03,000 --> 00:35:05,000
They're left with an engine enigma.

516
00:35:05,000 --> 00:35:15,000
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.

517
00:35:15,000 --> 00:35:25,000
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.

518
00:35:25,000 --> 00:35:28,000
There's a lot of oil in there.

519
00:35:28,000 --> 00:35:36,000
And Tori thinks their chances might be better if they replace the spark plug, which fires intermittently with this little device.

520
00:35:36,000 --> 00:35:43,000
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.

521
00:35:43,000 --> 00:35:50,000
It'll glow red hot, and that'll be a constant source of heat to ignite the black powder every time it enters the chamber.

522
00:35:50,000 --> 00:35:52,000
He's a bright spark, isn't he?

523
00:35:52,000 --> 00:35:54,000
Right. It's the moment of truth.

524
00:35:54,000 --> 00:36:00,000
Will this four-stroke engine go on gunpowder, or is it the end of the road for this myth?

525
00:36:00,000 --> 00:36:03,000
Gentlemen, start your engine.

526
00:36:05,000 --> 00:36:07,000
Glow plug.

527
00:36:09,000 --> 00:36:11,000
Black powder.

528
00:36:13,000 --> 00:36:16,000
Nothing. Zilch, zip, and bupkiss.

529
00:36:16,000 --> 00:36:23,000
In desperation, they put five grains of gunpowder directly into the cylinder and try again.

530
00:36:23,000 --> 00:36:25,000
Three, two, one.

531
00:36:28,000 --> 00:36:30,000
We've got a fire. Come on!

532
00:36:34,000 --> 00:36:37,000
You did get one push. We got one charge. We got one fire.

533
00:36:37,000 --> 00:36:39,000
Yeah, we got one ignition.

534
00:36:40,000 --> 00:36:49,000
Even a working engine won't work with gunpowder, and for that, we should probably all be grateful.

535
00:36:49,000 --> 00:36:52,000
Do we really have to talk about this one?

536
00:36:52,000 --> 00:36:58,000
No, but we will anyway. But you can see why over the ages it was so tempting to use black powder.

537
00:36:58,000 --> 00:37:01,000
It's got such high energy density, it would make a good fuel.

538
00:37:01,000 --> 00:37:06,000
But the stumbling black is getting the black powder into the piston and actually igniting it.

539
00:37:06,000 --> 00:37:08,000
Not to mention that these are dangerous.

540
00:37:08,000 --> 00:37:10,000
So you're ready to wrap this one up?

541
00:37:10,000 --> 00:37:11,000
Yep.

542
00:37:11,000 --> 00:37:12,000
Claim it.

543
00:37:12,000 --> 00:37:13,000
Busted.

544
00:37:13,000 --> 00:37:14,000
Easy. Busted.

545
00:37:14,000 --> 00:37:15,000
Busted.

546
00:37:38,000 --> 00:37:42,000
Jim and Jamie are ready to live out the ultimate boyhood dream.

547
00:37:42,000 --> 00:37:49,000
Fitting two potentially explosive air cylinders to an unsuspecting ski boat, then cutting loose.

548
00:37:52,000 --> 00:37:54,000
That's what it's going to be like.

549
00:37:54,000 --> 00:38:01,000
It's not a fully fledged myth, but after the success of an air cylinder blasting through a wall, it's impossible to resist.

550
00:38:02,000 --> 00:38:09,000
Step one is getting our stunt skipper installed in his wetsuit without having to blur some parts of your screen.

551
00:38:11,000 --> 00:38:15,000
Step two is filling the cylinders in the boat with compressed air from the truck.

552
00:38:19,000 --> 00:38:23,000
These tanks are actually filled with geese and they're complaining.

553
00:38:23,000 --> 00:38:28,000
And step three is seeing if Adam and Jamie can finally float their own boat.

554
00:38:29,000 --> 00:38:38,000
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 killing him.

555
00:38:38,000 --> 00:38:40,000
So much for the pep talk.

556
00:38:40,000 --> 00:38:45,000
It's a good rule of thumb that support staff should be seen and not heard.

557
00:38:45,000 --> 00:38:51,000
Jamie, so when we release you, we're going to pull off to the right hand side and you're going to steer to our left.

558
00:38:51,000 --> 00:38:52,000
Okay?

559
00:38:52,000 --> 00:38:54,000
You mean I'm going to steer off to port?

560
00:38:54,000 --> 00:38:58,000
Yes, you're going to steer off to port, you old salt.

561
00:38:58,000 --> 00:39:00,000
And we'll be to the starboard.

562
00:39:00,000 --> 00:39:04,000
What, left and right isn't good enough when there's water around?

563
00:39:04,000 --> 00:39:09,000
There's also plenty of spectators around, so they'll have to be careful.

564
00:39:09,000 --> 00:39:14,000
We've got a tour over here of kids in small boats.

565
00:39:14,000 --> 00:39:19,000
We're going to tell you past that tour before we release you.

566
00:39:19,000 --> 00:39:24,000
When all seems safe, the rocket boat is finally cut loose from the mothership.

567
00:39:24,000 --> 00:39:30,000
And remember, they're dealing here with twice the pressure used earlier to smash a brick wall.

568
00:39:30,000 --> 00:39:37,000
Jamie's ready and the mechanical throttle is gently nudged forward in the kick-ass direction.

569
00:39:50,000 --> 00:39:57,000
Oh dear, lots of noise and lots of spray.

570
00:39:57,000 --> 00:40:03,000
But that brief burst of speed clocked in at just over five knots on the speed gun.

571
00:40:03,000 --> 00:40:09,000
And the boat was propelled a mere 120 feet.

572
00:40:09,000 --> 00:40:12,000
Well, that was a whole lot of nothing.

573
00:40:12,000 --> 00:40:14,000
But Adam is more upbeat.

574
00:40:14,000 --> 00:40:16,000
That was excellent.

575
00:40:16,000 --> 00:40:21,000
I mean, it didn't do anything really important, but it was cool looking.

576
00:40:21,000 --> 00:40:27,000
Okay, there's no doubt we've just seen one of the best rooster tails this side of a barnyard.

577
00:40:27,000 --> 00:40:32,000
But let's face facts, Jamie can probably swim faster than five knots.

578
00:40:32,000 --> 00:40:36,000
The boys have given themselves one more chance to prove the concept.

579
00:40:36,000 --> 00:40:39,000
And they're ready to float some ideas.

580
00:40:39,000 --> 00:40:44,000
We may be able to optimize this a little bit if we choke the outlet down.

581
00:40:44,000 --> 00:40:47,000
And also, we're going to try to drop it into the water a little lower.

582
00:40:47,000 --> 00:40:58,000
Because I'm not sure that physics on this, but my hunch says that the air pushing more against the water instead of against just air would give us a little more hope.

583
00:40:58,000 --> 00:41:04,000
It's a bold decision that involves a lightning pit stop and a radical refit of the outlet valves.

584
00:41:04,000 --> 00:41:10,000
The full force of all that compressed air will now be released underwater.

585
00:41:10,000 --> 00:41:15,000
Jamie is also not going to go gingerly with the throttle this time.

586
00:41:15,000 --> 00:41:19,000
He is just going to push it all the way forward on the first go.

587
00:41:19,000 --> 00:41:27,000
And just expend all the power trying to get up to speed and stay at a speed and actually travel more than, you know, 120 feet.

588
00:41:27,000 --> 00:41:31,000
Tanks are refilled and the boat's back in position.

589
00:41:31,000 --> 00:41:33,000
It's now sink or swim.

590
00:41:33,000 --> 00:41:37,000
And Adam has some, well, vaguely helpful words of encouragement.

591
00:41:37,000 --> 00:41:41,000
Remember Jamie, experiments like this are 90% mental.

592
00:41:41,000 --> 00:41:45,000
I want you to be the boat. I want you to exist as one with the water.

593
00:41:45,000 --> 00:41:48,000
Think about the boat planning, the physics involved.

594
00:41:48,000 --> 00:41:51,000
Feel them in your body. Are you ready?

595
00:41:51,000 --> 00:41:54,000
What?

596
00:41:54,000 --> 00:41:57,000
I said just go for it.

597
00:41:57,000 --> 00:42:02,000
The rocket boat is unleashed and it anchors away.

598
00:42:08,000 --> 00:42:13,000
Ha ha ha ha ha ha ha ha ha.

599
00:42:13,000 --> 00:42:17,000
Let's assume that hysterical laughter is not a good sign.

600
00:42:17,000 --> 00:42:23,000
In fact, the boat traveled only half the distance of its first run.

601
00:42:23,000 --> 00:42:26,000
It was about the same as the other one, wasn't it?

602
00:42:26,000 --> 00:42:29,000
No, it wasn't even close.

603
00:42:29,000 --> 00:42:35,000
As for the speed gun, it was hardly worth installing the batteries.

604
00:42:35,000 --> 00:42:39,000
Well, I think that would proverbially be that.

605
00:42:39,000 --> 00:42:44,000
This lavish maritime experiment turned out to be a spectacular failure.

606
00:42:44,000 --> 00:42:48,000
Maybe it's time Jamie invested in a good, reliable outboard.

607
00:42:48,000 --> 00:42:52,000
I don't think he even made it like 60 or 70 feet that time.

608
00:42:52,000 --> 00:42:54,000
I don't know if you can calculate it in miles per hour.

609
00:42:54,000 --> 00:42:57,000
It'd be more like miles per day.

610
00:42:57,000 --> 00:43:01,000
So we have to ask ourselves, what's the wash-off?

611
00:43:01,000 --> 00:43:04,000
So Jamie, how are we going to wrap this one up? What do you call it?

612
00:43:04,000 --> 00:43:09,000
Well, we did get a tank to blow through a cinder block wall when we knocked the valve off.

613
00:43:09,000 --> 00:43:13,000
So that's confirmed. I mean, there were documented cases as well.

614
00:43:13,000 --> 00:43:20,000
And you can strap some air tanks to a boat and give it a little bit of power, but it's not that practical.

615
00:43:20,000 --> 00:43:21,000
It's not real power.

616
00:43:21,000 --> 00:43:24,000
Yeah, we need to go for the hydrogen and light it.

617
00:43:24,000 --> 00:43:27,000
It's another episode. We've got to let this one go.