Helicopter Physics Series #6 - LASER HELICOPTER BLADES - Smarter Every Day 49

(Carl) We have our bolt and thread here to balance, and we can run 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, am I saying that correctly?

(Carl) Yep, correct.

(Destin) So we are measuring the real-time 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. 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, it 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.