>> ♪ We've got two days to get this straight ♪ We got a challenge just won't wait our eyes are on the prize ♪ An engineer just set the date ♪ We got this client can't be late oh, no, it's go time ♪ Build it, test, fix it debug now and kick it ♪ Got to get it off the ground yeah ♪ Stick around and you'll see what teamwork's supposed to mean ♪ It's so key Design Squad Design Squad!

♪ >> All right, Design Squads.

This is it, your final challenge.

This is for all the marbles.

This challenge is like nothing you've seen before.

Now, Dewey and Leah, you're tied in the lead with 700 points each, which means that you two are vying for the final scholarship.

It's going to be up to you to decide the teams that are going to help you win the final challenge.

So are you ready to choose?

>> No.

>> Follow me into the garage.

Okay.

We'll flip a coin to see who's going to pick their team member first.

Now, we cannot have girls versus boys on this, because you've already done that twice.

So you have to have at least one person of the other gender on your team.

>> Okay.

>> All right?

Dewey, call it in the air.

>> Tails never fails.

>> Heads it is.

Leah, who do you pick first?

>> Who do you think Leah's going to pick?

>> I don't know.

>> I pick Kim, because Kim and I, every time that we've worked together, we've worked really well together.

>> Dewey?

>> I'll take Nick.

I think... same thing.

The two of us have always worked pretty well together, you know?

Plus he has a great jawline, so that's a plus.

>> Leah?

>> I will take... >> I think Leah will go for Deysi.

>> Yeah.

Deysi can weld like no other.

>> I think I'm going to take Deysi, because we also work really well together, and she's excellent at welding.

>> Dewey, who's next?

>> Maybe Dewey might choose Leah.

No.

( laughter ) >> I'll take Tomas.

He's pretty much... he's good all around with various tools, and he's always willing to go out and try and get something done.

>> Boys versus girls.

Going down!

>> Not another one of those.

>> I guess I'll take Jason, because I have to pick a boy.

>> I'll take Trejonda.

Fine with me.

>> All right.

Let's go and inform your new teammates.

>> Oh, they're coming.

>> Oh.

>> Hey.

>> Design Squads, we have a decision.

Leah, inform your team.

>> So my team is the Green Team, and that is going to be Deysi, Jason, and Kim.

>> Dewey, your Purple Team is?

>> Nick, Trejonda, and Tomas.

>> All right, Design Squads.

Go get your team colors on and meet me right back here to find out what your challenge is.

>> Let's take off our shirts.

( laughter ) >> No way!

>> Oh, my God!

>> So cool.

>> That's right, Design Squads.

You're building an offroad go-cart for your final challenge.

( cheers and applause ) And a race that includes all of you will determine the winner.

>> Oh, nice!

( laughter ) >> So let's head inside and discuss the specifics.

Hold up right there.

We've got a video to watch.

This is a video of the course.

Roll the tape.

The course is a half mile loop that you'll be doing twice.

First you're going to dive right into the woods.

The first thing that you're going to encounter is a mud pit.

There are rocks, there are logs, there is a jump that will jostle your very soul.

Now, the way the race is run, there will be two of you in the go-cart at all times.

There'll be a driver and a navigator.

After you go around once you'll be switching to the other two, who will drive around the second time.

Both teams are going to be running separately.

This is not a head-to-head race.

It's on time.

Now, the navigator has an additional job that's very key.

There are six flags positioned around the course.

They're numbered one through six, but they're not in numerical order through the course.

Now, the first pair is going to be picking up numbers one, two, and three.

The second pair picks up four, five, and six on their lap.

If you miss a flag, that's a minute penalty.

>> What?

>> Driver skill is going to be key.

Now, the team with the fastest time at the end wins.

Does that make sense to everybody?

>> Yeah.

>> Oh, one more very key thing I forgot to point out.

A girl has to drive and a boy has to drive.

So you're in for it.

Now, I know I don't need to remind you what's at stake here between Dewey and Leah.

It's the grand prize, the $10,000 scholarship from Intel Foundation.

( cheers and applause ) But wait, wait, wait.

There's more.

>> More?

>> There's more.

Our go-cart challenge is actually going to be featured in Make: magazine, which is all about backyard inventors.

And we've also been invited to appear at the Maker Fair, which is an international expo sponsored by the magazine that showcases do-it-yourself inventions.

>> That's great.

>> Without further ado, start your final brainstorming.

>> I'm pumped for this.

>> I know.

>> Jason, do you know how to do this?

>> I think the shocks go here in this bracket, like that.

>> So... and then this... >> All right, Green Team.

Let me give you the rundown on this stuff.

>> Okay.

>> Both teams will build their go-carts from a kit that includes: A 6.5 horsepower engine-- that's roughly equivalent to a lawnmower.

A front end with rack and pinion steering.

Suspension components.

Seats and seatbelts.

And hydraulic brakes.

The teams need to design and build the vehicle's frame or chassis, and a protective roll cage.

Then they must attach all of the components together.

It is imperative that you include three things-- a solid floorboard that's sheet metal, so that your feet don't fall through the frame and get cut, and so the rocks don't bounce through in your face.

You need bars around the sides in case you run into trees.

In case?

For when you run into trees.

And you have to have a roll cage in case you flip over.

>> All right, let's get chopping.

>> This is cool.

>> So cool.

>> Okay.

>> Are you sure this is where the shocks go?

>> Yeah, I think it's to use these guys here and here.

And those are welded onto the chassis, and those allow us to mount this entire sort of engine and back wheels there, so the whole thing's suspended.

>> Yeah.

We can have the chassis straight off, straight back from there and straight back from there.

I don't know if that's enough room for two... for the two chairs.

We have to make it flare out a little bit, then come down.

>> So pretty much we go back, and then we flare it out.

To support that you get yourself some cross pieces on there.

I'm saying stuff like that.

Then you throw those guys in there where the seats would be.

>> Okay, I see.

Trejonda's going to drive and I'm going to be her copilot, and Nick is going to be your copilot, right?

>> Works for me.

>> All right, great.

So we need to find the right measurements.

You want to sit, driver?

>> Okay.

>> Grab a seat.

>> Thanks, I will.

How's it going?

What are your goals for the end of the day?

What do you want to have accomplished?

>> I at least what do know our design, what it's going to look like, so at least we can come back in tomorrow and get building.

>> I would love to see full- scale layouts by the end of the day.

So, I mean, literally taking the chunks of the chassis that we gave you, throwing them up there on the table, and start drawing things out on the graph paper.

If you've got a top view and a side view, and you know what tubes are going to go where, implicitly your dimensions are already taken care of, because you... it's going to be that big.

Your scale's one to one.

Then you can really start building things.

Good?

>> Mm-hmm.

>> Okay.

>> So I think we need to find out where the seats go, because Jason's the tallest, and he is driving.

I think the farthest back should be where Jason is comfortable.

>> Yeah.

>> I can reach both pedals very easily.

>> You have to use both feet.

>> You don't feel comfortable using two feet?

>> No, I just though it was bizarre, Deysi, as in unusual.

>> That should tell you something right there.

>> Yeah, okay, Deysi, darling.

>> Kim and Deysi both really, really, really want to drive the cart, and only one girl can drive.

And I didn't really want to take it away from them, but the other one, of course, is going to be really disappointed, because they both really want to do it.

>> So I should test it, right?

>> My turn anyways.

>> Yeah, right.

>> I think we should settle this.

>> I don't think that we should choose, because I don't... whoever doesn't get chosen, I don't want them to get all annoyed and not want to work.

We should just wait until we get the cart built, and then we test whoever is the best driver.

Maybe we'll have a race or something.

And then we'll decide it then.

>> Yeah, Deysi might get pretty bitter.

>> Yeah.

( laughter ) >> Kim might poison me.

>> We have sort of a basic whole chassis thing ready to go.

>> This looks like a professional chassis.

>> Excellent.

>> All right, so we're not going to do the side view.

>> I think that two people should start on the chassis, two people should start on the roll cage, because they're two independent parts.

>> So we've got a lot to bend and weld.

>> Dewey's team is making their go-cart piece by piece.

Their chassis is designed as a separate module that's strong enough all by itself.

They'll tack the roll cage on top, and add protection for the sides later.

So Purple Team's go-cart will be heavy, a disadvantage when accelerating and going up hills.

And since Dewey's team is also heavier than Leah's, they should really be concerned about weight.

>> Handy dandy pipe bender.

>> Okay, we have where our seat is going to be.

>> So I think what we should do is have two main pieces of tubing starting from here and coming around, attaching into this right here, and then this piece up here, which attaches into the shocks.

>> Right.

>> And then have it come around into a roll cage and attach back.

>> I think it would be like this.

>> Right.

>> And then we can add on the side piece.

>> It's perfect.

>> Yes.

>> Nice.

>> Leah's team is designing their chassis, roll cage, and side impact protection so that together they create a strong integrated structure.

So Green Team will have a light, stiff frame-- an advantage when accelerating and going uphill.

>> Full scale drawing.

>> Full scale drawing.

>> So should we start working on a side view?

>> Yes.

>> Perfect.

>> It's good.

We've got the two pieces we need for the chassis.

This is the piece that's going to connect the front chassis.

Weld here, weld there.

>> I think our problem might be that we've got to make sure these guys line up.

Otherwise the engine and our whole back wheel set will be off kilter, and our back wheels will be crooked.

>> What's up, guys?

>> Hey, Nate.

>> Hello, Nate.

>> Got a layout yet?

How about the roll cage?

How's that now?

Do you guys have that drawn out, like, side view yet?

>> The side view is over there.

>> I'll just assume that it works, since your side view is in the trash can.

You're just going to do it out of your heads and hope that you cut all the pipes the right length and weld it together and it works magically?

>> Yep.

>> Going to hope real hard?

>> Really, really hard.

>> I'll trust your ability to hack it apart and fix it when you run into trouble.

But in the meantime, good luck tack welding your chassis.

>> Do you want to have, like, this whole piece of the roll cage coming down, like, say, here?

It would be one piece with two bends in it.

And then have the whole chassis be, like, another piece with one bend in it?

>> For strength it would be nice to have the bottom part of the chassis be, like, one piece, and then also the same thing.

If the cart rolls over, we want the roll cage to be really strong.

We want it to be one piece.

>> Yeah.

Okay.

So do we want to get started on bending?

>> Yeah, let's go for it.

>> Maybe one more.

>> Okay.

>> Nice.

>> I love that.

>> Nice.

>> We have a good deal of the chassis done.

>> All right, so next we have to the roll cage.

It's not going that high.

>> You want to check and see how much more we need?

>> Got it.

>> This is the stupidest looking thing.

>> This looks terrible.

>> I'm baffled.

I have no idea what we're doing.

Is this even that bad?

Hold on.

>> It's that bad.

>> You guys want help with the roll cage?

>> We got it.

>> Okay.

>> We do have this, right?

We're running out of time.

>> I think we have to start over, though.

>> Don't screw up this time.

You messed up because I wasn't there.

>> That's good.

>> That might be good.

>> That's beautiful.

>> Wow.

>> Gorgeous.

>> We make a good team.

>> Let's start welding.

>> Here, let's put it in.

>> That's beautiful.

>> That is beautiful.

>> Four... 43 and a half, 44... >> Time's up, Design Squads!

One day left!

Put your tools down!

>> Nice job, guys.

>> Ran into some problems, but... >> Yeah, some minor...

I wouldn't call them mistakes, but... >> You guys have got to take it a little more seriously, you know?

>> We were serious about bending it.

>> Yeah, a lot.

>> Yeah.

And we bent it a lot, so... >> So then pay attention a little bit more.

>> We have Nagging Nancy over here.

>> I think we have really good team chemistry, so if we can just, like, pull through with that... >> I'm really excited.

I, like..

I know you guys know how pumped I am about this challenge.

I'm so excited that you guys are... >> I just want to test it.

Like, I'm so glad that we're finally nearing the end, and we can drive it.

>> Oh, my God, I'm so excited.

>> Who's going to drive it?

>> We have tons of work to do.

>> We can add on the other pieces that we need, like the side piece.

>> What if we start, like, a piece that comes out this way and does this?

>> It looks like a rocket ship that way.

>> Yeah.

I like that idea a lot.

>> All right, let's go.

>> Okay.

>> I have the first side piece.

>> That's cool.

>> You and I can finish the roll cage that we worked on yesterday.

>> Yeah.

And if you guys can get these side pieces and get that out quick, then we'll meet back up and... >> Yeah, that's fine.

>> ...see where we've got to go from there.

>> What Tomas is doing right now is bending another same exact shape this way.

>> It's, like, perfect.

>> It's going to be parallel.

It's going to go on top.

>> Go higher?

All right.

>> And then put vertical pieces on down.

>> Yeah, Deysi needs to know if it's easy to get in and out, because, you know, she'll be the one getting the flags.

>> Excuse me, Kim?

Excuse me?

We have clearly not decided that yet.

>> Oh, okay, all right, Miss Thing.

>> Yeah, Miss Thing.

>> I will drive.

Deysi and I both want to be the girl driver.

>> I really want to drive.

Like, I love driving.

>> I'm crazy.

>> When it comes to racing, nobody beats me.

>> I am wilier.

>> I think I'm going to end up driving that car if that's the last thing I do.

>> But I'll win.

>> Good.

All right.

You want to see that thing?

>> It's still hot.

All right.

Oh, yeah.

>> Want me to hop in there with you?

>> Do I?

>> It's not really big, is it?

>> Oh, yeah, this looks pretty good now.

>> I like it now.

>> Not bad.

>> Are you comfortable in there?

>> I'm quite comfortable here.

>> All this work's making me tired.

>> It's a nice night.

I had a really great time.

>> I did, too.

You know, my parents aren't home, if you want to come in for a bit.

>> That would be nice.

( laughter ) >> We're wasting time here, you know?

>> All right, the seat belts are on, at least tacked on.

>> Yes.

Finally.

Let's just move this to the floor now so we can start doing the floor.

>> All right.

>> Okay.

>> All right, so if we got the seats in, let's get this back on the table and finish the rest of the assembly.

If you can just slide this piece of sheet metal under there we'll trace it and I'll start cutting out the floor pan.

>> Tracing, my friend.

>> Tack, tack, tack.

Tack everywhere.

>> Okay.

There we have it.

>> All right.

>> It's not bad, right?

>> I like it.

>> So what do we need to do now?

>> We can start running the brake lines and all that stuff so we can start getting close to having a working vehicle.

>> Okay.

One, two, three.

>> So all we need to do now is weld these guys on here.

>> Welding.

>> Our ignition switch, ignition button, and the choke cable.

>> That's, like, perfect.

We're eyeballing them.

>> Measurements, my friend.

>> Measurements?

>> I was mounting on the master brake cylinder over here.

You got the brake line with you?

>> Yeah, I'm ready.

>> All right, cool.

>> Let's put the wheels on.

>> Okay.

>> So this is the throttle cable, and it connects to the throttle in the engine.

>> An engine runs on a mixture of fuel and air.

In the team's engines, a chamber called a carburetor is where the fuel and air are mixed.

The throttle is a valve that controls the amount of air entering the carburetor.

When the air passes through a narrowing in the carburetor called the venturi, it creates a vacuum that draws fuel into the air flowing through the carburetor.

To go faster, the driver must press down farther on the gas pedal, opening the throttle more, allowing more air and fuel into the engine.

( engine trying to start ) >> That's so cool.

( engine trying to start ) >> Let's go for a ride.

>> Keys should be over there.

Let's get this thing started.

( engine trying to start ) ( engine starting ) >> It's okay.

Ours is going to turn on.

>> Go, go!

El gasso.

>> Quick, quick!

>> Punch it!

( engine trying to start ) >> I'm smelling gas, so is it... do you think the engine's flooded?

>> Hopefully.

>> I think that's just, like, a time thing.

>> Yeah.

>> If it sits overnight I think it'll be okay.

>> It was great.

>> Damn, she was wild in that thing.

I got scared for a while.

>> It was awesome.

>> "Slow down, slow down, slow down!"

>> We got this.

>> Oh, this thing is going to rock on race day.

>> Yeah.

>> Oh, this is awesome.

I am so pumped.

>> I can't wait.

>> Next time on Design Squad... >> Start your engine.

>> Will Leah or Dewey take the victory lap?

>> Yee-ha!

>> Run, run, run!

>> Go!

>> Hey, have you checked our Web site?

>> Yeah, it's pretty cool.

You can build projects on your own or with your friends, and you can win cool stuff.

>> Oh, check it out.

Go to pbskidgo.org.

Captioned by Media Access Group at WGBH access.wgbh.org