02x04 - Gravity Bikes

[bunniefuu]

♪ We've got two days to get this straight

♪ We've got two days to get this straight ♪ We've got two days to get this straight

♪ 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, today's your lucky day.

We're going to give you a little hint as to what today's

challenge is about.

Look up.

Anybody have a guess?

Bikes.

Something with bikes.

Something with bikes.

Are we racing them?

Good guesses all.

Let's go check out today's client.

Roll the tape.

Hi, I'm Tom Walen, and I race bikes.

That's amazing.

But these aren't your average bikes.

These are gravity bikes, which are basically stripped down BMX

bikes-- no pedals, no chain, and no gears.

They're called gravity bikes because they use gravity and not

pedal power to get yourself down the hill.

At speeds of over miles an hour, gravity biking is a real

rush.

Here's your challenge, Design Squads.

I want you to build me a gravity bike.

I don't care how you design the bike, as long as it meets the

specs of Gravity Sports International, which hosts

gravity bike races.

You'll face off in a head-to- head showdown on your own

gravity bike course.

Good luck, Design Squads.

Yeah?

Yeah?

Amazing.

So that's it.

You guys are building gravity bikes.

And you get to race them to see who's going to win.

[ laughter] We're giving you three bikes for

each team.

You can hack them apart, put them back together.

Now, as usual, you guys can use anything around the shop, and I

mean anything.

So look around this time, okay?

Okay.

Seriously.

Any questions?

I have a question.

Yeah?

Okay, so how do you decide what team gets what bikes?

We're going to have a special kind of pin the tail on the

donkey, per se.

Blindfolded, but without the donkey or the tail or the pin.

Anyway, come on, let's go over there.

This way.

Is that the bike you choose?

Excellent choice, Purple Team.

Green Team's up next.

Pick a rope, any rope.

This one?

Check out the extra rust feature.

This one?

All right.

Ah, you chose the one with flames.

Green Team, bicycle number three.

So any last questions before you guys go?

Take them into your workspaces and start brainstorming.

We get to build bikes!

I am so pumped.

Okay, all right.

So the rules, basically, total weight including the bike is

pounds.

Who's going to ride the bike?

I'd love to.

Me, too.

We have to talk about this.

He is heavier; I'm lighter, okay?

If you're heavy... if you're heavy, the bike won't start

really fast as the other team.

If you're heavier, you're going to keep on going faster.

Nick's right, but there's more to it than that, and it

starts with gravity.

The gravitational force between the Earth and you keeps you on

the ground.

And that force is your weight.

The Renaissance scientist Galileo Galilei proved that this

gravitational force causes objects, light or heavy, to have

the same acceleration when they fall.

So does that mean that Nick and Tomas are equally fast?

Well, no, and here's why.

When you move through the air, you create drag, a force that

slows you down.

And the faster you go, the greater the drag.

When drag matches the gravitational force of your

weight pulling you down the hill, you've hit your top speed.

To go faster, you can extend the wheel base so you can lie flat

and reduce your drag, or you can add weight to the bike so

there's more force pulling down the hill to overcome the drag.

So if Tomas and Nick are equally skilled riders, Nick, who's

heavier, should be faster.

Should we toss a coin?

Not a coin again.

I mean, Tomas, you're tails.

Nick, you're heads.

Ready?

Okay.

That's not how you flip a coin.

That's how I do it.

It's heads.

It's heads.

Are you okay?

No, no, I don't mind at all.

Oh, I thought he wasn't okay.

No, it's fine.

Okay, we're taking too long to decide.

We need to get this down, like, now.

Okay, you need to a good job with the welding, because he's a

heavyweight, okay?

I'll lose pounds if I have to to get on this bike.

I'll stop drinking water.

I'll do whatever.

That's a team member right there.

I'll do whatever it takes.

It's a bike.

I know.

I don't think there's a lot to debate about who's going to ride

it.

Do you want to do it?

Dewey has excitement in his face.

The wheel diameter is inches.

I saw some tires out in the shop.

We should probably grab them before Green Team does.

Yeah, let's go.

That's the one we need.

We need one more.

I think they're okay.

What do we know about gravity bikes?

They're really low to the ground.

Low to the ground.

They look kind of like this.

I feel like a longer bike might be better.

A longer bike would be more stable but harder to turn.

But if you're an experienced rider, it shouldn't be an issue.

Okay.

So do you want to do some sketches?

Yes, yes, we do.

We can take this part out and just put another piece in right

there and just extend it forward.

We don't have to extend that.

That body is fine.

It's going to take us a lot of work if we extend it and do

stuff.

What's the point of the drawing?

Because we're going to see the measurements and stuff.

I mean, if you saw the picture, we could completely

create our own body out of the parts.

Because we have still tubing out there which we can then weld

really easily.

And if we could just make the whole frame out of the tubing,

we could do any kind of design so the person's really low to

the ground.

You want to go out there and check the pieces?

Hey, let's go out there.

This is what I'd like to use for the bike.

Yeah.

Yeah.

I got this.

Are we going to use the fork and this?

Yeah.

Yeah.

Uh-huh.

Wait.

All we have to do is weld it here, and that's it, and then

this is all set.

So we're going to keep this, then?

Yeah, we're going to cut it here-- boom, boom.

You're going to have to cut it with an angle so that this is

straight.

You're getting too far ahead of what we're doing.

What's wrong?

Nothing.

We just haven't figured out the rest of the dimensions, and you

want to start cutting.

What's wrong with you guys?

You wanted to build this.

Let's build it.

That's it.

And then there's the extension right there.

What if we cut...

The handlebars are much longer.

Wait, I have an idea.

What if we cut this bike, like, here, off, and attach... and

take the steering column off that one, and attach this

steering column there?

I don't think we should be constricted by just using the

frames of these bikes.

I think we could even use this steering column, just cut

it here and put an extension piece, and then weld it here.

Yeah, I think that's what we need to do, essentially.

Yeah, that's fine.

Hey, guys, before we start hacking, just take everything

off that we don't need.

Then we can see about how much longer we need to extend it.

From there, we can move on.

There we go.

Hips want to be over the rear axle, right?

Yep.

So that's about there.

And then if I were to lean forward...

Think of, like, a jockey, you know?

Oh!

[ laughter] I'm going to take five.

Let's try this again.

This time...

Hey, guys.

Hey.

You guys are getting things cut apart nicely.

So you guys are fabricating your own frame from scratch?

That's cool, because you can do exactly what you want.

But it's also very ambitious.

So I hope you guys know that.

I want to really stress that before you cut all your metal

and start welding things together, you have an exact

design-- a real design, not just lines on a page, right?

Because I will not allow eyeballing on this.

You start eyeballing stuff and just welding it on wherever,

your frame's going to break and fall apart when you're going

miles an hour, which is never a good thing.

A really easy thing to do is just lay down a big sheet of

paper on the ground, trace out your wheels so that they're

exactly inches apart, and then start laying down the

pieces of metal right on the ground.

Good luck, guys.

I'll check in later.

It's going to be to scale, right?

Are we done with this?

Yeah.

You want to try?

Come here, let's see.

Lay down here.

I guess the proportions feel right.

I can't get a good feel, but it's not bad.

Okay, we're good.

Are we ready to weld?

Yeah, I'm good.

These are gussets.

It's going to come flat right about there, right?

So, I mean, we can get another piece that goes straight out

here.

A piece coming out straight, a piece coming out like that.

Looks like a very good idea.

That piece seems to work.

This one fits in.

And we'll get another one that will fit right below it and

run alongside.

And the after that, we'll just get the headpiece, we'll weld

that on, and that will form the new frame of the bike.

It looks really good, guys.

Thank you.

You know what angle you need to cut it at?

We want it at a slight angle so the wheel's just slightly

ahead.

Then we can bring over the chop saw and we can just cut that

angle.

Would that be our last thing today?

Probably.

We're running out of time.

Yeah.

Yes.

Starting to look like a bike, a really cool bike.

That's it for day one, Design Squads!

Day two is at the race site!

I feel like we did a good job today, guys.

Yeah.

Nice job for day one, guys.

This thing is going to fly.

Come on!

All right, so we're pulling in right now to the racetrack.

Holy...

That's it?

It's a lot thinner than I thought.

Gorgeous.

So for day two of the gravity bike challenge, we are at the

house of Dean Kamen.

Now, Dean Kamen is the founder of FIRST, which is an

international robotics competition.

Greetings.

Hi, Dean.

How are you?

Design Squads, meet Dean Kamen.

Hi.

I need to know how many of you have been on FIRST teams?

I have been.

Fantastic.

I guess, let me just ask you to promise me you're going to have

a safe day.

Thank you.

It was nice meeting you.

Are you guys ready to see your workspaces?

Yeah!

Go to it.

So guys, common machine shop in the middle.

Green Team's right here.

Purple Team's tent's up there.

Go to it.

Where did we leave off?

So...

So what do we need to do today?

I'd say feet and front tube are probably the two most

important things we've got to get on.

Well, painting, right?

Yeah.

I'd like to install brakes, now that I've seen the course.

No, I don't think...

We don't have to.

No, no, no, no, no.

They're going on.

They're going double on.

Right now I'm welding this front piece right here to our

main frame.

I really hope that's straight.

They can't do it without my welding, so...

Okay, so we're putting the dropouts in.

We can use it to put in the back wheel.

Okay, the dropouts are on.

Good job.

Good job.

You're doing really good welds.

Thank you.

Keep me alive.

You got it.

All right, guys, how am I going to sit on it?

Do you have to sit on it?

I was thinking about a rear fender and then maybe put a pad

on it or something that I could just sit on.

Well, it's your booty, so...

How's that look?

It looks great.

The piece that just got put in is the seat post.

And I don't think we're going to have an actual seat on it.

It's just going to be something more to lean on.

So we're in the process of making our seat.

What if we took, like, a piece of sheet metal, and... so this

is our tubing.

What if we just took, like, a piece of sheet metal that was

like this?

An elongated seat?

Yeah, like a banana seat, like, welded it to the pipe, and

then on top of that we can make, like, a foam cutout and make it

all comfy.

Awesome.

Cool.

And the plan is these edges are going to be bent over, and

it's going to be much smoother.

Nice.

Awesome for anger to just, like, whack it as hard as you

can.

Do the last piece, Kim.

I'm a big fan of this whole bike.

Yeah, me, too.

It's going to look good when we paint it.

Are we going to put it all together now?

Okay.

So this is the plate where Nick is going to kneel on, and all

I've got to do is smooth the edges.

So it's going to be...

I think the wheel should be fine.

Yeah, they're good.

Awesome.

Yeah, it looks really good.

Duct tape, man's best friend.

Let's go.

Nice and neat.

Awesome.

Seat's done.

That looks comfortable.

These are what need to be used for ballast.

We have to figure out, like, how much weight we want.

We're not going to have to worry about going over weight...

Yeah.

...with my slender physique.

The other team might, though, actually.

The other team might be overweight.

I was looking at their bike.

Their bike looks pretty heavy.

Looks good.

We just added pounds onto the bike, which is the maximum

amount of pounds you can add.

Okay, this is done.

Green team, you guys look sharp.

This is Tom Walen.

Hi.

What's up?

So what do you think about the fact that we actually

started... like, we made this out of scratch?

I'm really impressed, especially not having ridden one

before or really seen them very much.

You guys definitely ran with it pretty well.

All right, guys.

Well, put the last finishing touches on, I guess, and we'll

see you at the training session and then the race.

All right, thank you.

It's the bag of decals.

Are we done?

I think this might do it.

It's done.

Yes!

I'm so excited.

It looks really good.

Oh, yeah.

Purple Team, this looks good.

Meet Tom Walen, your client.

Hey.

Let's check it out.

It looks good.

I like the extended frame.

I think it'll make it a little smoother going down the hill,

and the weight will help you carry some speed in the flats.

All right, guys, good work.

Can't wait to see it in action.

Okay.

Good luck, you guys.

Great, sure.

All right, guys, I'm going to go get suited up, and we can try

to do a quick little weigh-in, see how much I weigh in full

attire.

Hey, guys.

Hey.

Like it?

Yeah.

Okay, you are .

Don't eat, now.

You're at .

This is perfect.

I'm Gravity Man.

I like it.

Hold it, hold it.

It's about , which is what Green Team is without their

bike.

So they've got about pounds on us, so we're just going to

have to go faster and tighter on the turns then.

Which you can do.

I definitely can.

With this, I'm invulnerable.

Racer ready, set, go.

That is so much fun.

The bike handled pretty good, but we might want to try and

take a little weight off and see if that'll help me maneuver

around the turns faster, because I felt like I had to pull a lot

more.

Because the only place he's going to pass me is on the

straights.

So get ahead with the start and try and hold it in the

straights.

Racers ready, set, go.

I got up to there.

The weight felt a lot more stable on the turns and the

straightaway.

I think Dewey has a lot better start than me, but I think I

have the faster overall speed.

So we'll see which one works out for who.

This ain't about the points.

This is just I want to win this thing.

I want to get racing.

Ready to get the job done.

Are you ready?

...two people, it's going to be a totally different course.

Stay low on the bike.

You know everything.

We can't really say anything more.

Be awesome.

Be awesome, yeah.

We'll see you at the end.

See you guys at the bottom.

Good luck.

All right, guys, this is it.

Final race of the gravity bike challenge.

You guys ready?

Yeah.

Yeah.

Do it.

Racers ready.

Set.

Go.

[ cheering]

What happened?

Nick crashed.

Where is he?

I hope he's all right.

What a wipeout.

Such a lead.

You okay?

Yeah, I'm fine.

Just mad at myself.

Here he comes.

Oh, all right.

I see him.

Oh, you're okay, that's good.

Sorry, guys.

When we started, I didn't have as bad of a jump as previous

tries.

Coming to the first turn, I overtook him.

Third turn I didn't know if he was still coming.

I was going to go hard down the middle, then just took it a

little too wide.

If you slowed down there, man, you had that.

There was no way I was catching you.

You're just way faster on that thing than I am.

I don't know.

Congratulations.

Dude, that was your race to win.

Great racing.

All right, Design Squads.

Now, there's a clear and obvious winner, Purple Team, so

points goes to each member of Purple Team.

Congratulations.

[ applause] You guys did an awesome job

with both of them.

You got really creative with your frames.

So congratulations to both of you.

And it was a great race up until the crash.

And including the crash.

Yeah, and including the crash.

Way to be aggressive in both the design, the construction,

and the racing-- for everything.

You guys rock.

It was really good.

Nice job, guys.

Green Team's win from behind gives Leah the leading edge with

points.

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 pbskidsgo.org.

Coming up...

Transform my body.

Propel me through the water.

I don't think we can just strap an umbrella to her.

That's not engineering.

Next time on Design Squad.