the nut in and out to get the perfect balance. (Destin) That's pretty smart. I bet a smart

guy came up with that. (Carl) oh.. a.. brilliant person. [laugh]

Oh hey. Yeah. You see that? You see how awesome this is?

Hey it's me Destin. Welcome to Smarter Every Day. We're continuing our

study of helicopters and we have just come up with my best invention since the chicken

powered steady cam. Well.. Carl helped too. [laugh] You know, the

whole helicopter thing. It is one of the more dangerous things and you know you're living right if you

need laser goggles and a helmet. (Carl) And where's my helmet? [chuckle]

I only have one. He can hide in the toy closet. We're in my son's

bedroom. Alright so let's explain what we've got here. (Carl) Alright. We've put

a laser in place of our blades. (Destin) Lasers are like bacon

they make everything better. (Carl) Oh yeah. We've balanced it out here with our high-tech little gadget

and ah we're going to show how collective and cyclic

pitch changes as a disc. (Destin) What we do with this is we are measuring the pitch

output on this rotor grip. Excuse me, is that

am I saying that correctly? (Carl) Yep correct. (Destin) So we are measuring the realtime pitch

as it goes around a revolution. (Carl) Getting a nice visual

representation of it. (Destin) Sweet. OK where do you want me? (Carl) Alright how about we

ah you get right behind it. (Destin) Over here? (Carl) Yep right here.

and ah we'll project it against the wall. Here we go.

(Destin) We'll shut the ah shut the closet. Oh another thing we made it so when it

spins up it turns it on using the ah gyro force

ah excuse me the centrifugal force. Ready. (Carl) Here we go. [Rotor spinning up]

(Carl) Alright. (Destin) [unintelligible excited]

(Carl) So ah here we've got zero pitch, all round.

and if we give a collective input, our line goes up

positive collective, negative collective it will go down.

If we give any cyclic input the disc will

or the line will tilt, right left forward, back.

(Destin) So to be clear, we're measuring the pitch, so

the rotor shaft is not changing at all, other than rotation, correct.

(Carl) Yes. (Destin) Alright so the pitch of the blade

is changing as we go around a revolution because the swashplate input

(Carl) the ah grip changes from positive to negative pitch every

revolution. (Destin) That's awesome. I am extremely excited

about this. This is the best visual representation I've ever.. oh

there's one more thing. It's also pointing 90 degrees out of phase right?

(Carl) Well, yes but that puts it in the phase that it would normally operate.

(Destin) Alright hold on. I don't understand how you're gonna do this without a helmet.

Alright, so if you think about, OK, when you say it's in

the phase that it would normally operate, the laser is shining 90 degrees off (Carl) The laser is pointing this

direction and as we get a forward cyclic input tilts

down and that transitions to take effect 90 degrees when the

(Destin) That's gyroscopic precession. (Carl) Gyroscopic precession. (Destin) Alright, so let's zoom in on the swashplate

ah just for people who don't know what swashplates do, give me a

(Carl) This is the swash plate. (Destin) Collective input up. (Carl) Collective up. (Destin) Collective down.

(Carl) and it can tilt forward back left or right. (Destin) That's your cyclic input.

Alright you can give collective, and you can see

the light goes up, and that would pull the helicopter up [unintelligible]

negative, and if we get cyclic, it

changes the tilt of our line. (Destin) OK what is the front of the helicopter

towards you or towards this wall over here? (Carl) The front of the helicopter is towards the camera's

left. (Destin) Got it, so let me go back over here

and try to get it on the wall here. Alright do it again.

(Carl) Alright here we go. Left, forward,

Right, back, up and down.

(Destin) This is so awesome I want to cry.

I think our contribution to science for the day is done. (Carl) Alright!

I'm Destin. You're getting Smarter Every Day.

[ Captions by Andrew Jackson ]

Captioning in different languages welcome. Please contact Destin if you can help.