January 18, 2019 • 39 mins
How do helicopters work? Why does a helicopter need a tail rotor? What is a quadrocopter? Join Jonathan and Chris as they look at the quirky contraptions called helicopters.
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Speaker 1 (00:04):
Get in touch with technology with tech Stuff from how
Stuff Works dot Com. Hey there, and welcome to tech Stuff.
I'm your host, Jonathan Strickland. I'm an executive producer with
How Stuff Works in I heart radio and I love
all things tech. And it's time for another classic episode,
(00:24):
and this one, which originally published on February twenty seven,
two thousand twelve, Chris Palette and I talk about how
helicopters work. As I recall, the Marines say that the
helicopters fly by beating the air into submission. So, without
further ado, let's get to chop off. We're gonna talk
(00:45):
about helicopters today. Yes, and it's rising that we haven't
talked about it before. Yeah. Well, when you start looking
into what is involved in making a helicopter work, I
can see exactly why we haven't done it before. Well,
you know the helicopter business US have it have its
ups and down. Yeah. Nice, I like how you did that.
Um yeah, So so let's talk about helicopters. So, I'm
(01:07):
sure all of you are familiar with the concept of
a helicopter, but when did these things? How did how
did we come up with this idea? When did this
originally spring to mind. Okay, well, uh, you know, it
is something that has been on my mind since I
was a kid. I've always loved helicopters. So the other
(01:28):
day Jonathan sent me a video that I couldn't watch
because my current bandwidth was too low on my Internet connection,
and it took me two days to actually watch it.
But it was a video of some very tiny quadricopters. Yeah,
they were called nano quadricopters in the video itself, although
that is a misnomer since nano typically means one billion.
(01:50):
And they were not that small. No, they fit on
the palm of someone's hand. Yeah, they're about the size
of the palm of your hand. And uh, I was
thinking about how, uh, how unusual the quadracopter is because
it doesn't have a tail roader like a traditional helicopter does. Um. Yeah,
they're very very maneuverable. Um and uh and I thought,
you know, hey, Jonathan, why don't we talk about helicopters
(02:12):
because we never really talked about them before. So, right,
so that's how I came to mind. Yeah, that's how
I came to mind. Now, how how the idea of
a helicopter actually came to mind for human beings in general.
That dates back pretty far in human history. And it
all begins with a toy. Yeah, you know, and I
think just about everybody who's gone to their school fair
(02:34):
or whatever is one one of these little you know,
seventy two cent uh stick with a propeller on it
and you spin in the palm of your hand and
let go and it'll fly up and then crash down
to the earth. But they weren't always made from plastic, no, No,
they were. The Chinese had a little top that they
used where the top was had feathers on it, Yes,
(02:58):
and it did the same sort of thing. You would
put a put the stick between your hands, the feathers
will be at the top. You spin the stick very quickly.
The feathers would spin and it would create some lift
and the sick would fly up in the air and
then come back down. Pretty simple, yep. And as it
turns out to the concept is is pretty simple. Basically,
you're you're creating an air foil. Yes, Um that instead
(03:20):
of like an airplane wing where you're going forward, Um,
it is going straight up simply because um, the the
air that that moves over the air foil, it creates
lift is taking it straight up instead of forward. Yes,
So I guess to to really kind of discuss this,
we should probably talk about a little bit about the
parts of a helicopter, so that way we can explain
(03:44):
what these these parts actually do and how they achieve flight.
So the blades that we talk about, that's a rotor, right,
So the rotors are affixed to a rotor mast. That's
the part that actually creates the the turning motion, and
that makes the blades go round in a circle. And
the blades themselves are angled and they can that angle
(04:06):
can change depending upon a control um. There are different
control rods that can change the the um the attitude
of those blades. So you have, uh, two of them.
Actually there's the cyclic controller which can control them individually. Yes,
that's also known as the stick, right, Yeah, that's the
that's the stick. And then there's a was it the
(04:27):
collective one, right, yes, the collective pitch lever. What that
does is it actually changes the attitude of all of
the rotors, the main rotors at the same time. Um.
And that both of those are important for various maneuvers
with the helicopter. But we'll get into that in a second.
There's also with the rotors, there's a a stabilizer. Because
(04:48):
you've got these long air foils that are extending out
from a shaft and they're turning around and around. There's
a chance that they're gonna start, you know, flopping around
a little bit, causing some issues, you know, of the
stabilizer is there to help add some rigidity there so
that these blades will will maintain the right shape so
that you can fly. It's kind of funny too, because
(05:10):
apparently it was just one of those things that someone
added to the helicopter um uh And as as it
turns out, it it made a major improvement in the
stability and and flyability of helicopters. Yeah, the early helicopters
when they were flying, it was a pretty bumpy ride
and it was definitely a challenge for a pilot to
(05:30):
maintain control because it just you know, without that stabilizer,
it just like you were saying, it just wasn't as fliable.
So it was definitely a good addition to the parts
of a helicopter. There's a there's a there are two
plates they are on the rotor mast, all right, that
(05:52):
that also are a big part of the helicopter. It's
called the upper swash plate and the lower swash plate.
And despite what you might think, they are not joined
by a swash buckle. Instead, if you imagine that, they
imagine two plates to two round plates, right, and they're
(06:12):
both they both have the the shaft of the motor
of the rotor rather goes straight through these two plates.
The lower plate is stationary, it does not turn. On
top of the lower plate are ball bearings, yes, And
then on top of the ball bearings is the upper swashplate,
which does turn. The ball bearings are what allow it
to turn over. The lower swashplate, now the swashplate. The
(06:36):
reason that's important is remember when I was talking about
the collective the collective control that changes the attitude of
all the blades at the same time that what that
actually does is it allows that plate to tilt either
forward or backward, or however you need it to, so
that you can make the helicopter veer in the direction
(06:57):
you want it to go. Because really, until this point,
what we were doing was going up and down. We
weren't going left or right, or over that way or
back this way. Because if you try, if you have
one of those toys that we were talking about before.
With the blade on the stick, you point it straight
up and it goes straight up, and then it'll drift
off a little bit to the side, but you don't
(07:18):
really control that. If you pointed it, you know at
your friend, it's going to go in his or her direction.
And that's what the swash plates allow the pilot of
the helicopter to do it. It helps filp the blades
and and the helicopter starts flying in that direction. Yes,
because it adds it adds a second element. Right, you
first have the first element you have is lift, Right,
(07:40):
The second element you would have is thrust. Yes, so
when you start to change the attitude of the blades,
you have both lift and thrust. Now, there is a
point where if you were to tilt that beyond a
certain threshold, you would no longer have enough lift to
counteract the weight of the helicopter itself, and it would
start to lose altitude. They might be moving forward, but
(08:01):
it's going to be going lower and lower until you
correct that. And that's one of the reasons why UH
piloting a helicopter is so challenging. In fact, when we
get into the different controls. You'll find out you're using
both your legs and both your arms to try and
maneuver a helicopter, and so it takes a lot of concentration. Yeah. Yeah,
it's also why you don't see a lot of people
(08:22):
flying helicopters and loop to loops. Yeah, that's let's their
air wolf that right. Yeah, but then no, that is
true because once you get beyond that certain threshold, you
no longer have the lift necessary to keep you in
the air. Uh. And these blades are connected to that
rotor mast through blade grips, that's the technical term for
where the blades fit into this rotor mast. And on
(08:45):
the very top of the rotor mast, you have something
that's that's got an interesting name. Yes, the Jesus nut. Yes,
it really is called that. It's called the Jesus nut.
And uh, there are various furies as to why it's
called that, and I don't know what any of I
don't know the truth of any of them. Yes, the
one that we have an article on the site. Yes,
it's a it's a really good article too, with lots
(09:06):
of really helpful illustrations. So if you are interested in
helicopters and you really want to get a look at
what these different parts look like. I highly recommend you
check it out because it's it's one of the more
exhaustive articles on the site. I would say, yeah, I would,
I would agree with that and very very illustrative what
you're doing here when you're flying a helicopter. Um. So, yeah,
(09:29):
we were talking about the tail rotor just a moment ago. Yes, Um,
very important in the in the design of a helicopter.
So here's another thing about helicopters. You've got this blade
turning around and around, this creating lift, and when the
lift gets strong enough to counteract the weight of the
helicopter is going to rise in the air. Without a
tail rotor. Yeah, if you've ever wondered why that's there. Yeah,
(09:49):
without a tail rotor, which is that little, that little
smaller propeller that's on the end of the tail of
a helicopter. Without it, the body of the helicopter itself
would start spin in a direction opposite that of the rotors.
So if the rotors are spinning in a clockwise direction,
then the helicopter will start to spin in a wider
Shian's direction. You just wanted to use, Yes, I did
(10:12):
so badly counterclockwise. For those of you who do not
speak archaic English, hey, where are my Shakespeare Homi's at
So anyway, Yes, the the helicopter would spin without any
other other force to counteract this, the helicopter would start
to spin in the opposite direction, which would probably be
an unpleasant experience for anyone inside that helicopter. Yes, yeah,
(10:34):
so the rotor What that does is it helps to
create thrust to counteract the spinning motion so that the
helicopter stays stationary. And by controlling the speed of that rotor,
you can actually turn the helicopter to the left or
to the right, not banking it. But actually if you're
in if you're hovering in place, you can change the
speed that that rotor turns and then turn your helicopter
(10:58):
so it's facing an opposite direction, so if it started
facing north, you can maybe face west. That kind of thing.
And of course, uh, for for this, we have a
a guy named Igor to to thank for that. Yes,
Igor did a great job. Of all the people who
experimented with the idea of being able to levitate a person,
(11:20):
I mean there were there were many, including a our
our friend Leo, Yeah, Leonardo da Vinci yea. Yeah, he
tried to create something that he called the air screw,
which was a screw shape, and the idea was that
with four people powering this man powered, of course back
in Leo's day, that if you were able to turn
this air screw fast enough, it would be able to
(11:41):
create enough lift to lift the machine off the ground. Now,
he never got this to work, but it was sort
of the basis of the idea of what would eventually
become a helicopter, although it changed dramatically by the time
the helicopter actually appeared. Yep. Now, Igor Sikorsky, if you
spend any time at all paying attention to helicopters, that
(12:03):
name is going to be very familiar to you. Um
was a Russian who experimented with the idea of helicopters
and then kind of moved away to get into other
types of airplane flight and then sort of came back
to it later on. Yea, His early attempts were not
met with very much success. Now, so he decided, hey,
you know what, let's just put this on the back
burner and look at something that I know will work.
(12:26):
And then eventually, once he felt more confident, he revisited
this idea of the helicopter. Yeah, back in the around
the nineteen thirties, I think is when when he started
really having some luck with it and he realized that
he was going to need something to prevent the helicopter
body from spinning like that without any kind of force.
So he decided to mount a tail rotor on his
(12:49):
helicopter too. And basically it's it's creating force in a
sideways manner that that is resisting the force that that
would naturally cause the helicopter to turn. So um, you know,
hats off to igor. Yeah, and that was a brilliant idea.
It was the nineteen thirty nine when he created the
VS three hundred, which was based off these early designs,
(13:13):
and it actually worked. It lifted him up into the air.
It was a bit of a bumpy ride. But then
he ended up trying to uh, you know, he refined
the design of it and then um, actually had broke
a record. On May six one, he broke the world
helicopter endurance record and stayed in the air for one hour,
(13:35):
thirty two minutes and twenty six point one seconds. And yeah,
that's that's pretty impressive. I mean, for for an invention
that people had played with for centuries really, but no
one had really cracked it. It was a big jump.
And speaking of jumps, we should say that between the
time of the the top toy that was invented in
(13:55):
ancient China and the time that Sikorski created the first
working helicopter, there were a lot of other people who
were involved in trying to make this work, and some
of their contributions led into Sikorski's work. Yes, but a
lot of these early inventions that were created we call
them hoppers because they could they could lift off the
(14:18):
ground briefly, but they couldn't really sustain flight for any
length of time, and they didn't really have any way
of changing the direction of that flight. It just would
go up and down, I mean, apart from being pushed
around by whatever wind happened to be in the area. Yeah,
being pushed around by wind, that's not a problem. But
then so he breaks the record. It turns out that,
(14:39):
you know, the helicopters would become really important in warfare.
That actually became a very uh well, the United States
in particular really dependent upon helicopters in conflicts in Korea
and Vietnam. Hey, you know I've seen mash Yeah, yeah,
it starts off with one through early morning guy. See
(15:02):
uh yeah, And this was this was a pretty interesting development.
I mean you see a lot of of the experimental
aircraft from that era just became oddities. Yes, yes, which
you can still find autogyros. And we should explain what
the difference between an autogyro and a helicopter is. So
(15:22):
with a helicopter, those rotors were talking about, those are
powered that that rotor mast turns underpower. There's an engine
and a transmission. The engine provides power, transmission converts it
over into the mechanical energy that the rotors need in
order to turn, and that is what makes the the
blades turn fast enough to create the lift. Autogyros have
(15:45):
unpowered rotors, so there is a there there is a
set of rotors on top of an autogyro, so in
a way it kind of resembles like a miniature helicopter.
But then there's a propeller that's either in the front
or the back of the autogyro. It all depends on
the design of a specific autogyro, which what that's what
provides thrust and what happens is it generates an air
(16:09):
flow that is directed up at the rotors that are
above the autogyro, and that that upward flowing amount of
air is what makes the blades start to turn. And
you just keep increasing the air flow, which again makes
the blades turn faster until that helps counteract the weight
of the autogyro. And that's what allows the autogyro to fly.
(16:30):
But there's no motor turning those blades. It's all just
from the flow of air. Yeah. As a matter of fact,
some now, some of the more modern helicopters also have
a second engine, which can help you know, of course
if in the case of the first engine going out,
um but you know there there's some redundancy there, uh
(16:51):
now in the more modern helicopters, especially for military helicopters
that might be affected by enemy fire. Right sure, Yeah,
you have an engine failure, then you can switch over
to a second engine and hopefully prevent catastrophe. So let's
talk a little bit about the controls that are inside
a helicopter. Of course, you have lots of different um
(17:13):
uh dials and indicators that give you information about the
environment and uh information about your helicopter's performance. Those are
all there's they're too numerous to name, really, but the
actual controls. When we were talking about using both your
hands and both your feet, well, one hand is gonna
be on that cyclic pitch lever. So this is the
(17:34):
lever that controls the angle of each of the rotor
blades individually. And uh this one is used mainly to
tilt the craft at either side or forward and backward.
But it's it's done in uh very it's not it's
it's not the one that changes the swashplate. That's the
collective pitch leaver. So that's that's your second one that
(17:57):
you're holding with your other hand. Um. It's mainly used
things like take off and landing. It's used to increase
or decrease the pitch of all the rotor blades at
the same time. And it's mostly responsible for up and
down movements, not things like forward, backward, left, right. Uh.
Then you've got your foot pedals and these are what
control the tail rotor, and so using the the tail rotors,
(18:21):
this is how you can turn the the helicopter so
it faces a different direction. You're not banking it, but
you're turning it. Um or you're using it just to
keep it steady. Uh. And and if you're wondering, you know, well,
what about hovering? Isn't that easy? No, Hovering is actually
pretty difficult to do because you have to you have
(18:42):
to get everything in a neutral position, and then you
have to keep making minor adjustments in order to maintain
the position that you're in. In fact, pilots will have
to pick a spot that they can look at and
try and maintain their attitude and altitude uh by by
referencing where that spot is and making minor adjustments constantly. Yes. Yeah,
(19:06):
and it helps to uh to have um uh an
experienced pilot on board, just because not only is there
the matter of looking at the electronic components in the
craft itself, but to orient him or herself with the
land around, just to to give a visual representation of
(19:28):
what's going on. And that's that's one of those things
that's especially important. Because the wind does blow helicopters around.
You have to take these things into into account, and
um one of the best ways to do that is
to use that visual orientation to make sure that you
haven't drifted off to some degree. Now, let's talk really
(19:48):
quickly about what the process is like if you are
taking off helicopter, So there's several steps. First, what you
would have to do is you have to open up
the throttle that you and speed up these rotors so
that they start turning out a speed fast enough to
create the amount of lift you need. UM you do
this by actually twisting the handle of one of the
(20:09):
levers you're holding in your hands and twisting it one
way opens the throttle and twisting it the other way
closes the throttle. So that's you know, that's essentially like
sitting stepping on the accelerator of a of an automobile. UM.
So the next what you would do, once you've got
the the rotors moving at the right speed, you'd start
to pull back on the collective control and that's what's
(20:32):
going to raise the swashplate assembly and that's going to
change the pitch of the rotor blades, and then that's
what's going to let you direct that lift the in
the right direction so that you can actually get off
the ground. Then you would start to press down on
the left foot pedal because you would need to get
(20:55):
the tail rotor spinning so that you could counteract that torque.
We we're talking about the the the tendency for the
chassis to spend in the opposite direction of the rotors.
Right as soon as you're lifting off the ground, you're
going to be it's going to be much easier for
the rotors to start to spin the body of the helicopter,
the fuselage. Yes, so if you weren't, if you were
not making that rotor tail rotor spin, you would start
(21:18):
to go on a little spinny spinny d it yourself,
which would most likely end in disaster. Yeah, so yeah,
you you then would start to actually add a counteractive
thrust through the tail rotor by pressing down that left pedal. Now,
if you got to a point where you needed to
turn or you need to slow that down, you could
(21:39):
stop pressing down the left pedal and start pressing down
the right pedal, and that's what would counteract that. Um.
Then you keep pulling back on that collective control while
holding down the left foot pedal, and once the correct
amount of lift is created, your helicopter will leave the
ground and you'll be flying over the air and delivering
(22:01):
traffic reports like nobody's business. All right, let's uh, let's
take a quick break. I'm still recovering from my truly
awful and unrecognizable Schwarzenegger uh impersonation. Let's take a quick
break to think our sponsors. Yeah, it's um, it's pretty interesting. Uh.
(22:29):
And there's even other challenges to flying a helicopter, right,
I mean, not only is it requiring a lot of coordination,
but even just the way that the air flight works.
When you start traveling, say forward, you're moving forward at
at around UM twenty knots of airspeed, you have to
end up transitioning, transitioning from hovering, which is more or
(22:52):
less staying fairly stationary, to moving on a full forward
flight phase. And there's that's where you have the effective
translational lift or et L. And at that point the
pilot would start to ease up on that left foot
pedal and move closer to a neutral setting. And there's
(23:13):
gonna be a shutter that you'd feel through the rotor
system because you are going to fly out of what
is called rotor wash. And rotor wash is not where
you go to a place where people start pouring sud
sea water all over your rotor blades and then squirt
them down. It's not that's not a rotor wash. Rotor
(23:33):
wash is actually turbulence which is created by these rotor
blades turning so quickly, and you fly through your own turbulence.
Then once you get to a certain angle, that turbulence
is not no longer directed in your flight path, and
you end up having this much more smooth experience. So
before you hit that, that flying in that helicopter might
(23:55):
feel a little well, pardon the pun, but choppy, because
you just you know, you're actually flying through turbulence that
you have created through the helicopter itself. Um. By the way,
I don't know if you've ever heard this, but I
have friends who were in the Marines, and they said
that the way the Marines would explain helicopters, as they say,
helicopters fly by beating the air into submission, which is
(24:20):
a very Marines kind of thing, Simper five. So the yeah,
it's a it's a pretty interesting method of flight. It's
amazing to me even seeing them now. I mean, you
can see them helicopters outside the windows of our office
fairly frequently. We're in a part of Atlanta where we'll
see traffic helicopters or news helicopters fly overhead. Um and
(24:43):
In fact, when the article was being written for the site,
Marshall Brain, the founder of how Stuff Works, had contacted
a company in Atlanta that did helicopter tours and helicopter
pilots worked for him and managed to get the president
of the company to agree to fly a helicopter so
that we could get some video, which led to one
of the more famous incidents and how stuff works, where
(25:05):
this helicopter pilot uh flew relatively close to the building
and anyone who was on our floor knew what was
going on, well not even everyone here. Most of the
people knew what was going on, but anyone on any
other floor had no idea. And I'm pretty sure we
terrified half of an office building. Sorry about that, but
(25:28):
it was Marshall Brain who did that, um so, not us,
not us. But yeah, we've got some pretty cool footage
from those videos. I mean, how could you not. We
have some pretty cool footage from those videos that are
part of this article. So if you want to see
what I'm talking about in action, go to how stuff
works dot com look up how helicopters work. And we
have other articles about helicopters as well, including specific ones
(25:51):
like how the Apache helicopter works, which goes into more
detail about other systems besides the flight control system. It's
also got weapons systems and its role in military applications,
where of course just really focusing on the basics of
helicopter flight. But let's also talk now, do you have
anything else you want to talk about specifically about helicopters
before I move on to quadrocopters. Um, no, go ahead, okay,
(26:12):
So quadricopters, Now, if you haven't seen one of these,
these tend to be these little uh unmanned aerial vehicles
that have four rotor systems on them. Yeah, the ones
I've seen have been primarily for models for entertainment purposes. Yeah,
our C controlled ones or sometimes that you can control
them through a smartphone. In our RC episode we talked
(26:34):
a little bit about them. What are you when are
you grinning out? Someone's going to write in about RC
controlled I'm sorry, control can stop by over my a
t M machine with my PIN number, and I've got
an r C controlled helicopter. How about that? How about
them apples? Then? Anyway? Yes? I okay, so anyway, Yes,
there's also ones that you can control with your smartphone.
The parrot a r drone which was at c S
(26:58):
the first time I think was maybe three or four
years ago, and that was very impressive to see. That
was the first time I had ever seen a four
rotor h copter, a quadricopter. And uh, you might wonder, well,
how do these things work. They don't have a tail rotor.
There's no tail rotors, so how do they counteract that
torque we were talking about. It's actually pretty clever. Two
(27:22):
of the rotors on a quadricopter turn in one direction
and the other turn to turn in the other direction,
and they cancel each other out, yes, the opposite. They
both produce enough torque so that you can keep the
quadricopter from turning in place, either one way or the other.
And when I say you, I don't really mean you,
(27:44):
because most of these have pretty sophisticated microprocessors on board
that really register, measure the amount of torque and all
the other elements here so that they can make adjustments
to the speed of each of those rotors in or
to maintain the proper attitude and altitude of that device.
(28:04):
So all you have to do is say I want
you to go over there, and then all these other
microprocessors do everything that they can to make that happen
while keeping it nice and safe, which is pretty cool.
I mean you you know, you think about all the
work that they have to do in order for that
to to turn out that way. Well, there are lots
of different kinds of quadricopters, and if you do want
(28:26):
to make it turn like if you want to make
it bank one way or the other. Again, what happens
is it the quadricopter adjust the speed at which certain
rotors are spinning, so the lift changes exactly, Yes, the
lift changes and the torque changes, so the two together
can make you stray fit to the left or to
(28:47):
the right, or forward or backwards. I've even seen, I mean,
we've seen some that can do flips because what they'll
do is they'll is one side will spin very very
quickly while the other side stops spinning. It'll lift up
into the air, and then they'll switch the directions of
the rotors so that it flips it in mid air
and lands back, you know, right side up with all
(29:08):
rotors going, so it goes back into flying. And the
video that we were talking about at the very top
of this podcast, it was a little unnerving really because
we were seeing groups of these quadricopters that were all
following the same program, and you could have them grouped
into individual little squadrons, like squadrons of four quadricopters, and
(29:33):
I think there was something like, uh, they were using
twelve and all. So they had three groups of four
and they would send the three groups of four through
and through an obstacle course and they would maneuver past
each other, but they would all the four quadricopters would
move as a single unit, which was kind of creepy,
you know, to see something move like several small things
(29:54):
all moving together as one like that was a little odd.
And they can make a move through things like windows,
which was way griev er. Yeah, I got I got
these images of of drones coming into your house. Hello
Mr Smith, Yeah, we have something we'd like to say
to you, Oh skynet. Yeah, no, it's a yeah, your
(30:17):
water bill. While we hover around the topic of helicopters,
it's time for us to take another break to thank
our sponsor. So the video we're talking about specifically, and
I'll try and link to this when we do some
show notes, is called precise aggressive maneuvers for autonomous quad
(30:42):
quad rotors. Quadt I was gonna say quadrocopters but spelled
quad rotors and it totally threw me off. But this
was done through the GRASP Lab g r a s
P at the University of Pennsylvania. Yeah, that's a general
robotics Automation Sensing and Perception. Yeah, so this particular video
shows these uh, these tiny quadricopters moving through various maneuvers.
(31:07):
What's interesting here is that the one I'm looking at
right now, like it's this is one of those videos
that just got really popular all of a sudden, right
like that. Several of our listeners are watching listeners, um
are Yeah, but the video that I'm looking at right
now was uploaded so two years ago and we're just
(31:27):
now starting to catch on it. Sometimes the Internet is
a little slow to catch on the memes, That's what
I'm saying. But yeah, this was something that started to
make it make the rounds and uh and on Google
Plus and on Facebook recently and Twitter as well, and uh,
just one of those cool things that it turns out
it's been in the works for a few years, but
we just started to get the attention of the world
(31:48):
in general. But it shows a really interesting approach to
programming these quadricopters and showing their capabilities and what they
might be used for. And you might think, okay, well,
you know, you put a camera on these and then
suddenly you've got a spy plane. But you could also
have it for something like first responders. So there's a
(32:08):
let's say there's an accident and you send some of
these in uh that to in order to to scan
the scene and make sure that one it's safe enough
to send in an emergency response teams, and to whether
or not it's even necessary to start send an emergency
response teams. You may send in. Let's say there's a
building that's that's on fire, and you send some of
these over to look because I mean, these things, relatively
(32:31):
to a human life, are cheap. They're nothing. So you
can make as many of these as you like. They're
gonna be. They might be a little expensive, but it's
less expensive than losing a human life. So you send
these things in and take a look around. It may
turn out that, well, you know what, that building was
completely abandoned. There was no one in there, So we
don't need to risk the lives of any emergency responders.
We can just use the firefighters to try and put
(32:52):
this fire out. So that's the kind of idea that
we'd be looking at from that point forward. And there's
a lot of other possibilities, Um besides that. I mean
that's traffic, you know, having them look at traffic, things
like that. That's these are all possibilities. No, granted, you
have to figure out how to supply the power to
these things. Most of them are battery operated, and the
(33:14):
battery will only last so long. So it's not like
you would send out, you know, wake up, punch the clock,
send out fifty quadricopters to cover the city and then
at the end of the day they all come back. Uh,
So you know, it's not like it's a it's a
it's not like you can solve all the problems just
by sitting out quatricopters. But it's a cool idea and
(33:35):
the videos are pretty awesome. Also, the the the parrot videos,
those are really cool too because those have incorporated smartphone
applications and you can see through the camera. You can see. Yes,
you can use it as you can use as a
surveillance tool. Although it is it's whisperer quiet. I've used
that I've used that phrase like eight times on tech
(33:57):
stuff recently. But yeah, it's it's not like it's subtle.
It's you'll hear a when you're playing with one of
these things, but you can use it to look through
the camera. And they've even incorporated games into the drones
so that you can if you have one and your
friend has one, you're both controlling them with your smartphones.
You can play a game where you're essentially kind of
(34:18):
like laser tag but with drones. How awesome is that?
And then they also have other games where, uh, they'll
have targets show up on your screen. They're not they
don't actually exist in real life. It's an augmented reality
program where the targets appear on your screen and your
job is to fly your drone so that you can
use a little imaginary laser to shoot down these targets.
(34:40):
It's neat stuff like that, and it really, I mean,
beyond the fact that a quadricopter is pretty darn cool
by itself. Yeah yeah, yeah. As a matter of fact,
that one in particular also has some bumpers that it's
sort of be a shield for the for the rotors. Yes, yes,
so that you can fly it indoors. A lot of
uh model helicopters I've seen are are more traditional and
(35:04):
do not have that kind of protection for the rotors.
So you you wouldn't want to necessarily fly it around
your house even you want to bang into a lamp
or something. Yeah, even I've seen some of the small
ones that are pumped sort of palm sized. Um. But yeah,
I mean if if it actually touches something, it could
uh damage it or the copter or both, and that
that would be you could bang into someone serious. So
(35:26):
but yeah, the a r drone when the little bumpers
you're talking about, they look like little disks that fit
around like hollow disks. So yeah, they fit right around
where the rotors are. And so it kind of makes
us a safer device, so that if it were to
bump into something, you would just get bumped, you wouldn't
get cut. Yeah. Still you wouldn't want to get it
around people or or pets certainly. Um. So yeah, but
(35:51):
it makes it a little safer. Yeah, it's kind of neat.
And then uh, I've also heard from enthusiasts people who
really enjoy flying r C helicopters and r C quadricopters
that if you're interested in this, a quadricopter in general
tends to be a lot easier to fly because those
microprocessors I was talking about do a lot of the
(36:12):
fine tuning for you. So all you do is you
tell it I want you to go up, and it
takes care of the controls that needs to to make
those different rotors spin at the right speeds and makes
it go up or turn left or turn right or
straight or whatever. So it's it can be a lot
of fun and it can get people into the hobby
and it's not incredibly challenging. On the other hand, flying
(36:34):
a remote control helicopter requires a lot of finesse. Not
quite the same sort of thing you would need if
you were flying a life size helicopter, but still it
does require that you control things like the tail rotor
and that you're very methodical with the way that you
try and turn the helicopter, maneuver it, take off and landings.
(36:57):
It's it's actually, from why I understand one of the
more challenge ng RC vehicles to control, because there's just
so much you have to keep in mind. However, that
being said, even though it's really challenging, I also hear
it's one of the most enjoyable experiences, very rewarding because
once you master that, you know, you really have a
sense of accomplishment. So if you are interested in that
(37:18):
kind of hobby, I recommend you go ahead and you know,
check it out. See what, see what it would look.
How much it would cost to get into it, because
these these devices can be fairly expensive. Sometimes sometimes the
few hundred dollars is on the low end of some
of these devices. But it is something that if you're
interested in learning more about flight, if you're interested in
(37:39):
just kind of getting a new skill, it's kind of
a cool thing to get into. And uh, you know,
you know what, I've never actually written in a helicopter,
have you No, that's one of my goals I really
want to do. I want to do a hellic just
a simple helicopter tour. Nothing, nothing terribly you know, exciting.
I was thinking about actually doing one in Hawaii e
(38:00):
because I thought, well, heck, that would be amazing, you know,
the landscape and everything. But I happened to be married
to someone who finds air travel to be the uh
not the most relaxing experience, and so I didn't do that.
I did go parasailing though. Interesting. Yeah, totally not at
all like flying in a helicopter, I would imagine. Yeah,
(38:22):
I don't even know why I brought it up. All right,
So let's let's wrap this up. Guys. This was fun.
I'm glad we did this because, you know, we like
to try and tackle lots of different kinds of topics
here at tech Stuff. We like to talk about the
things that are a big social phenomena, you know, things
like like social networking sites and how technology affects us
(38:42):
personally or as a society. And we like to talk
about companies, and we like to talk about innovators. But
once in a while it's fun to take a specific
type of technology and really deconstructed and talk about the
various parts and what makes it go tick or fly
in this case. I hope you guys enjoyed that class episode.
If you have suggestions for future episodes of tech Stuff,
(39:03):
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how stuff works dot com
Get in touch with technology with tech Stuff from how
Stuff Works dot Com. Hey there, and welcome to tech Stuff.
I'm your host, Jonathan Strickland. I'm an executive producer with
How Stuff Works in I heart radio and I love
all things tech. And it's time for another classic episode,
(00:24):
and this one, which originally published on February twenty seven,
two thousand twelve, Chris Palette and I talk about how
helicopters work. As I recall, the Marines say that the
helicopters fly by beating the air into submission. So, without
further ado, let's get to chop off. We're gonna talk
(00:45):
about helicopters today. Yes, and it's rising that we haven't
talked about it before. Yeah. Well, when you start looking
into what is involved in making a helicopter work, I
can see exactly why we haven't done it before. Well,
you know the helicopter business US have it have its
ups and down. Yeah. Nice, I like how you did that.
Um yeah, So so let's talk about helicopters. So, I'm
(01:07):
sure all of you are familiar with the concept of
a helicopter, but when did these things? How did how
did we come up with this idea? When did this
originally spring to mind. Okay, well, uh, you know, it
is something that has been on my mind since I
was a kid. I've always loved helicopters. So the other
(01:28):
day Jonathan sent me a video that I couldn't watch
because my current bandwidth was too low on my Internet connection,
and it took me two days to actually watch it.
But it was a video of some very tiny quadricopters. Yeah,
they were called nano quadricopters in the video itself, although
that is a misnomer since nano typically means one billion.
(01:50):
And they were not that small. No, they fit on
the palm of someone's hand. Yeah, they're about the size
of the palm of your hand. And uh, I was
thinking about how, uh, how unusual the quadracopter is because
it doesn't have a tail roader like a traditional helicopter does. Um. Yeah,
they're very very maneuverable. Um and uh and I thought,
you know, hey, Jonathan, why don't we talk about helicopters
(02:12):
because we never really talked about them before. So, right,
so that's how I came to mind. Yeah, that's how
I came to mind. Now, how how the idea of
a helicopter actually came to mind for human beings in general.
That dates back pretty far in human history. And it
all begins with a toy. Yeah, you know, and I
think just about everybody who's gone to their school fair
(02:34):
or whatever is one one of these little you know,
seventy two cent uh stick with a propeller on it
and you spin in the palm of your hand and
let go and it'll fly up and then crash down
to the earth. But they weren't always made from plastic, no, No,
they were. The Chinese had a little top that they
used where the top was had feathers on it, Yes,
(02:58):
and it did the same sort of thing. You would
put a put the stick between your hands, the feathers
will be at the top. You spin the stick very quickly.
The feathers would spin and it would create some lift
and the sick would fly up in the air and
then come back down. Pretty simple, yep. And as it
turns out to the concept is is pretty simple. Basically,
you're you're creating an air foil. Yes, Um that instead
(03:20):
of like an airplane wing where you're going forward, Um,
it is going straight up simply because um, the the
air that that moves over the air foil, it creates
lift is taking it straight up instead of forward. Yes,
So I guess to to really kind of discuss this,
we should probably talk about a little bit about the
parts of a helicopter, so that way we can explain
(03:44):
what these these parts actually do and how they achieve flight.
So the blades that we talk about, that's a rotor, right,
So the rotors are affixed to a rotor mast. That's
the part that actually creates the the turning motion, and
that makes the blades go round in a circle. And
the blades themselves are angled and they can that angle
(04:06):
can change depending upon a control um. There are different
control rods that can change the the um the attitude
of those blades. So you have, uh, two of them.
Actually there's the cyclic controller which can control them individually. Yes,
that's also known as the stick, right, Yeah, that's the
that's the stick. And then there's a was it the
(04:27):
collective one, right, yes, the collective pitch lever. What that
does is it actually changes the attitude of all of
the rotors, the main rotors at the same time. Um.
And that both of those are important for various maneuvers
with the helicopter. But we'll get into that in a second.
There's also with the rotors, there's a a stabilizer. Because
(04:48):
you've got these long air foils that are extending out
from a shaft and they're turning around and around. There's
a chance that they're gonna start, you know, flopping around
a little bit, causing some issues, you know, of the
stabilizer is there to help add some rigidity there so
that these blades will will maintain the right shape so
that you can fly. It's kind of funny too, because
(05:10):
apparently it was just one of those things that someone
added to the helicopter um uh And as as it
turns out, it it made a major improvement in the
stability and and flyability of helicopters. Yeah, the early helicopters
when they were flying, it was a pretty bumpy ride
and it was definitely a challenge for a pilot to
(05:30):
maintain control because it just you know, without that stabilizer,
it just like you were saying, it just wasn't as fliable.
So it was definitely a good addition to the parts
of a helicopter. There's a there's a there are two
plates they are on the rotor mast, all right, that
(05:52):
that also are a big part of the helicopter. It's
called the upper swash plate and the lower swash plate.
And despite what you might think, they are not joined
by a swash buckle. Instead, if you imagine that, they
imagine two plates to two round plates, right, and they're
(06:12):
both they both have the the shaft of the motor
of the rotor rather goes straight through these two plates.
The lower plate is stationary, it does not turn. On
top of the lower plate are ball bearings, yes, And
then on top of the ball bearings is the upper swashplate,
which does turn. The ball bearings are what allow it
to turn over. The lower swashplate, now the swashplate. The
(06:36):
reason that's important is remember when I was talking about
the collective the collective control that changes the attitude of
all the blades at the same time that what that
actually does is it allows that plate to tilt either
forward or backward, or however you need it to, so
that you can make the helicopter veer in the direction
(06:57):
you want it to go. Because really, until this point,
what we were doing was going up and down. We
weren't going left or right, or over that way or
back this way. Because if you try, if you have
one of those toys that we were talking about before.
With the blade on the stick, you point it straight
up and it goes straight up, and then it'll drift
off a little bit to the side, but you don't
(07:18):
really control that. If you pointed it, you know at
your friend, it's going to go in his or her direction.
And that's what the swash plates allow the pilot of
the helicopter to do it. It helps filp the blades
and and the helicopter starts flying in that direction. Yes,
because it adds it adds a second element. Right, you
first have the first element you have is lift, Right,
(07:40):
The second element you would have is thrust. Yes, so
when you start to change the attitude of the blades,
you have both lift and thrust. Now, there is a
point where if you were to tilt that beyond a
certain threshold, you would no longer have enough lift to
counteract the weight of the helicopter itself, and it would
start to lose altitude. They might be moving forward, but
(08:01):
it's going to be going lower and lower until you
correct that. And that's one of the reasons why UH
piloting a helicopter is so challenging. In fact, when we
get into the different controls. You'll find out you're using
both your legs and both your arms to try and
maneuver a helicopter, and so it takes a lot of concentration. Yeah. Yeah,
it's also why you don't see a lot of people
(08:22):
flying helicopters and loop to loops. Yeah, that's let's their
air wolf that right. Yeah, but then no, that is
true because once you get beyond that certain threshold, you
no longer have the lift necessary to keep you in
the air. Uh. And these blades are connected to that
rotor mast through blade grips, that's the technical term for
where the blades fit into this rotor mast. And on
(08:45):
the very top of the rotor mast, you have something
that's that's got an interesting name. Yes, the Jesus nut. Yes,
it really is called that. It's called the Jesus nut.
And uh, there are various furies as to why it's
called that, and I don't know what any of I
don't know the truth of any of them. Yes, the
one that we have an article on the site. Yes,
it's a it's a really good article too, with lots
(09:06):
of really helpful illustrations. So if you are interested in
helicopters and you really want to get a look at
what these different parts look like. I highly recommend you
check it out because it's it's one of the more
exhaustive articles on the site. I would say, yeah, I would,
I would agree with that and very very illustrative what
you're doing here when you're flying a helicopter. Um. So, yeah,
(09:29):
we were talking about the tail rotor just a moment ago. Yes, Um,
very important in the in the design of a helicopter.
So here's another thing about helicopters. You've got this blade
turning around and around, this creating lift, and when the
lift gets strong enough to counteract the weight of the
helicopter is going to rise in the air. Without a
tail rotor. Yeah, if you've ever wondered why that's there. Yeah,
(09:49):
without a tail rotor, which is that little, that little
smaller propeller that's on the end of the tail of
a helicopter. Without it, the body of the helicopter itself
would start spin in a direction opposite that of the rotors.
So if the rotors are spinning in a clockwise direction,
then the helicopter will start to spin in a wider
Shian's direction. You just wanted to use, Yes, I did
(10:12):
so badly counterclockwise. For those of you who do not
speak archaic English, hey, where are my Shakespeare Homi's at
So anyway, Yes, the the helicopter would spin without any
other other force to counteract this, the helicopter would start
to spin in the opposite direction, which would probably be
an unpleasant experience for anyone inside that helicopter. Yes, yeah,
(10:34):
so the rotor What that does is it helps to
create thrust to counteract the spinning motion so that the
helicopter stays stationary. And by controlling the speed of that rotor,
you can actually turn the helicopter to the left or
to the right, not banking it. But actually if you're
in if you're hovering in place, you can change the
speed that that rotor turns and then turn your helicopter
(10:58):
so it's facing an opposite direction, so if it started
facing north, you can maybe face west. That kind of thing.
And of course, uh, for for this, we have a
a guy named Igor to to thank for that. Yes,
Igor did a great job. Of all the people who
experimented with the idea of being able to levitate a person,
(11:20):
I mean there were there were many, including a our
our friend Leo, Yeah, Leonardo da Vinci yea. Yeah, he
tried to create something that he called the air screw,
which was a screw shape, and the idea was that
with four people powering this man powered, of course back
in Leo's day, that if you were able to turn
this air screw fast enough, it would be able to
(11:41):
create enough lift to lift the machine off the ground. Now,
he never got this to work, but it was sort
of the basis of the idea of what would eventually
become a helicopter, although it changed dramatically by the time
the helicopter actually appeared. Yep. Now, Igor Sikorsky, if you
spend any time at all paying attention to helicopters, that
(12:03):
name is going to be very familiar to you. Um
was a Russian who experimented with the idea of helicopters
and then kind of moved away to get into other
types of airplane flight and then sort of came back
to it later on. Yea, His early attempts were not
met with very much success. Now, so he decided, hey,
you know what, let's just put this on the back
burner and look at something that I know will work.
(12:26):
And then eventually, once he felt more confident, he revisited
this idea of the helicopter. Yeah, back in the around
the nineteen thirties, I think is when when he started
really having some luck with it and he realized that
he was going to need something to prevent the helicopter
body from spinning like that without any kind of force.
So he decided to mount a tail rotor on his
(12:49):
helicopter too. And basically it's it's creating force in a
sideways manner that that is resisting the force that that
would naturally cause the helicopter to turn. So um, you know,
hats off to igor. Yeah, and that was a brilliant idea.
It was the nineteen thirty nine when he created the
VS three hundred, which was based off these early designs,
(13:13):
and it actually worked. It lifted him up into the air.
It was a bit of a bumpy ride. But then
he ended up trying to uh, you know, he refined
the design of it and then um, actually had broke
a record. On May six one, he broke the world
helicopter endurance record and stayed in the air for one hour,
(13:35):
thirty two minutes and twenty six point one seconds. And yeah,
that's that's pretty impressive. I mean, for for an invention
that people had played with for centuries really, but no
one had really cracked it. It was a big jump.
And speaking of jumps, we should say that between the
time of the the top toy that was invented in
(13:55):
ancient China and the time that Sikorski created the first
working helicopter, there were a lot of other people who
were involved in trying to make this work, and some
of their contributions led into Sikorski's work. Yes, but a
lot of these early inventions that were created we call
them hoppers because they could they could lift off the
(14:18):
ground briefly, but they couldn't really sustain flight for any
length of time, and they didn't really have any way
of changing the direction of that flight. It just would
go up and down, I mean, apart from being pushed
around by whatever wind happened to be in the area. Yeah,
being pushed around by wind, that's not a problem. But
then so he breaks the record. It turns out that,
(14:39):
you know, the helicopters would become really important in warfare.
That actually became a very uh well, the United States
in particular really dependent upon helicopters in conflicts in Korea
and Vietnam. Hey, you know I've seen mash Yeah, yeah,
it starts off with one through early morning guy. See
(15:02):
uh yeah, And this was this was a pretty interesting development.
I mean you see a lot of of the experimental
aircraft from that era just became oddities. Yes, yes, which
you can still find autogyros. And we should explain what
the difference between an autogyro and a helicopter is. So
(15:22):
with a helicopter, those rotors were talking about, those are
powered that that rotor mast turns underpower. There's an engine
and a transmission. The engine provides power, transmission converts it
over into the mechanical energy that the rotors need in
order to turn, and that is what makes the the
blades turn fast enough to create the lift. Autogyros have
(15:45):
unpowered rotors, so there is a there there is a
set of rotors on top of an autogyro, so in
a way it kind of resembles like a miniature helicopter.
But then there's a propeller that's either in the front
or the back of the autogyro. It all depends on
the design of a specific autogyro, which what that's what
provides thrust and what happens is it generates an air
(16:09):
flow that is directed up at the rotors that are
above the autogyro, and that that upward flowing amount of
air is what makes the blades start to turn. And
you just keep increasing the air flow, which again makes
the blades turn faster until that helps counteract the weight
of the autogyro. And that's what allows the autogyro to fly.
(16:30):
But there's no motor turning those blades. It's all just
from the flow of air. Yeah. As a matter of fact,
some now, some of the more modern helicopters also have
a second engine, which can help you know, of course
if in the case of the first engine going out,
um but you know there there's some redundancy there, uh
(16:51):
now in the more modern helicopters, especially for military helicopters
that might be affected by enemy fire. Right sure, Yeah,
you have an engine failure, then you can switch over
to a second engine and hopefully prevent catastrophe. So let's
talk a little bit about the controls that are inside
a helicopter. Of course, you have lots of different um
(17:13):
uh dials and indicators that give you information about the
environment and uh information about your helicopter's performance. Those are
all there's they're too numerous to name, really, but the
actual controls. When we were talking about using both your
hands and both your feet, well, one hand is gonna
be on that cyclic pitch lever. So this is the
(17:34):
lever that controls the angle of each of the rotor
blades individually. And uh this one is used mainly to
tilt the craft at either side or forward and backward.
But it's it's done in uh very it's not it's
it's not the one that changes the swashplate. That's the
collective pitch leaver. So that's that's your second one that
(17:57):
you're holding with your other hand. Um. It's mainly used
things like take off and landing. It's used to increase
or decrease the pitch of all the rotor blades at
the same time. And it's mostly responsible for up and
down movements, not things like forward, backward, left, right. Uh.
Then you've got your foot pedals and these are what
control the tail rotor, and so using the the tail rotors,
(18:21):
this is how you can turn the the helicopter so
it faces a different direction. You're not banking it, but
you're turning it. Um or you're using it just to
keep it steady. Uh. And and if you're wondering, you know, well,
what about hovering? Isn't that easy? No, Hovering is actually
pretty difficult to do because you have to you have
(18:42):
to get everything in a neutral position, and then you
have to keep making minor adjustments in order to maintain
the position that you're in. In fact, pilots will have
to pick a spot that they can look at and
try and maintain their attitude and altitude uh by by
referencing where that spot is and making minor adjustments constantly. Yes. Yeah,
(19:06):
and it helps to uh to have um uh an
experienced pilot on board, just because not only is there
the matter of looking at the electronic components in the
craft itself, but to orient him or herself with the
land around, just to to give a visual representation of
(19:28):
what's going on. And that's that's one of those things
that's especially important. Because the wind does blow helicopters around.
You have to take these things into into account, and
um one of the best ways to do that is
to use that visual orientation to make sure that you
haven't drifted off to some degree. Now, let's talk really
(19:48):
quickly about what the process is like if you are
taking off helicopter, So there's several steps. First, what you
would have to do is you have to open up
the throttle that you and speed up these rotors so
that they start turning out a speed fast enough to
create the amount of lift you need. UM you do
this by actually twisting the handle of one of the
(20:09):
levers you're holding in your hands and twisting it one
way opens the throttle and twisting it the other way
closes the throttle. So that's you know, that's essentially like
sitting stepping on the accelerator of a of an automobile. UM.
So the next what you would do, once you've got
the the rotors moving at the right speed, you'd start
to pull back on the collective control and that's what's
(20:32):
going to raise the swashplate assembly and that's going to
change the pitch of the rotor blades, and then that's
what's going to let you direct that lift the in
the right direction so that you can actually get off
the ground. Then you would start to press down on
the left foot pedal because you would need to get
(20:55):
the tail rotor spinning so that you could counteract that torque.
We we're talking about the the the tendency for the
chassis to spend in the opposite direction of the rotors.
Right as soon as you're lifting off the ground, you're
going to be it's going to be much easier for
the rotors to start to spin the body of the helicopter,
the fuselage. Yes, so if you weren't, if you were
not making that rotor tail rotor spin, you would start
(21:18):
to go on a little spinny spinny d it yourself,
which would most likely end in disaster. Yeah, so yeah,
you you then would start to actually add a counteractive
thrust through the tail rotor by pressing down that left pedal. Now,
if you got to a point where you needed to
turn or you need to slow that down, you could
(21:39):
stop pressing down the left pedal and start pressing down
the right pedal, and that's what would counteract that. Um.
Then you keep pulling back on that collective control while
holding down the left foot pedal, and once the correct
amount of lift is created, your helicopter will leave the
ground and you'll be flying over the air and delivering
(22:01):
traffic reports like nobody's business. All right, let's uh, let's
take a quick break. I'm still recovering from my truly
awful and unrecognizable Schwarzenegger uh impersonation. Let's take a quick
break to think our sponsors. Yeah, it's um, it's pretty interesting. Uh.
(22:29):
And there's even other challenges to flying a helicopter, right,
I mean, not only is it requiring a lot of coordination,
but even just the way that the air flight works.
When you start traveling, say forward, you're moving forward at
at around UM twenty knots of airspeed, you have to
end up transitioning, transitioning from hovering, which is more or
(22:52):
less staying fairly stationary, to moving on a full forward
flight phase. And there's that's where you have the effective
translational lift or et L. And at that point the
pilot would start to ease up on that left foot
pedal and move closer to a neutral setting. And there's
(23:13):
gonna be a shutter that you'd feel through the rotor
system because you are going to fly out of what
is called rotor wash. And rotor wash is not where
you go to a place where people start pouring sud
sea water all over your rotor blades and then squirt
them down. It's not that's not a rotor wash. Rotor
(23:33):
wash is actually turbulence which is created by these rotor
blades turning so quickly, and you fly through your own turbulence.
Then once you get to a certain angle, that turbulence
is not no longer directed in your flight path, and
you end up having this much more smooth experience. So
before you hit that, that flying in that helicopter might
(23:55):
feel a little well, pardon the pun, but choppy, because
you just you know, you're actually flying through turbulence that
you have created through the helicopter itself. Um. By the way,
I don't know if you've ever heard this, but I
have friends who were in the Marines, and they said
that the way the Marines would explain helicopters, as they say,
helicopters fly by beating the air into submission, which is
(24:20):
a very Marines kind of thing, Simper five. So the yeah,
it's a it's a pretty interesting method of flight. It's
amazing to me even seeing them now. I mean, you
can see them helicopters outside the windows of our office
fairly frequently. We're in a part of Atlanta where we'll
see traffic helicopters or news helicopters fly overhead. Um and
(24:43):
In fact, when the article was being written for the site,
Marshall Brain, the founder of how Stuff Works, had contacted
a company in Atlanta that did helicopter tours and helicopter
pilots worked for him and managed to get the president
of the company to agree to fly a helicopter so
that we could get some video, which led to one
of the more famous incidents and how stuff works, where
(25:05):
this helicopter pilot uh flew relatively close to the building
and anyone who was on our floor knew what was
going on, well not even everyone here. Most of the
people knew what was going on, but anyone on any
other floor had no idea. And I'm pretty sure we
terrified half of an office building. Sorry about that, but
(25:28):
it was Marshall Brain who did that, um so, not us,
not us. But yeah, we've got some pretty cool footage
from those videos. I mean, how could you not. We
have some pretty cool footage from those videos that are
part of this article. So if you want to see
what I'm talking about in action, go to how stuff
works dot com look up how helicopters work. And we
have other articles about helicopters as well, including specific ones
(25:51):
like how the Apache helicopter works, which goes into more
detail about other systems besides the flight control system. It's
also got weapons systems and its role in military applications,
where of course just really focusing on the basics of
helicopter flight. But let's also talk now, do you have
anything else you want to talk about specifically about helicopters
before I move on to quadrocopters. Um, no, go ahead, okay,
(26:12):
So quadricopters, Now, if you haven't seen one of these,
these tend to be these little uh unmanned aerial vehicles
that have four rotor systems on them. Yeah, the ones
I've seen have been primarily for models for entertainment purposes. Yeah,
our C controlled ones or sometimes that you can control
them through a smartphone. In our RC episode we talked
(26:34):
a little bit about them. What are you when are
you grinning out? Someone's going to write in about RC
controlled I'm sorry, control can stop by over my a
t M machine with my PIN number, and I've got
an r C controlled helicopter. How about that? How about
them apples? Then? Anyway? Yes? I okay, so anyway, Yes,
there's also ones that you can control with your smartphone.
The parrot a r drone which was at c S
(26:58):
the first time I think was maybe three or four
years ago, and that was very impressive to see. That
was the first time I had ever seen a four
rotor h copter, a quadricopter. And uh, you might wonder, well,
how do these things work. They don't have a tail rotor.
There's no tail rotors, so how do they counteract that
torque we were talking about. It's actually pretty clever. Two
(27:22):
of the rotors on a quadricopter turn in one direction
and the other turn to turn in the other direction,
and they cancel each other out, yes, the opposite. They
both produce enough torque so that you can keep the
quadricopter from turning in place, either one way or the other.
And when I say you, I don't really mean you,
(27:44):
because most of these have pretty sophisticated microprocessors on board
that really register, measure the amount of torque and all
the other elements here so that they can make adjustments
to the speed of each of those rotors in or
to maintain the proper attitude and altitude of that device.
(28:04):
So all you have to do is say I want
you to go over there, and then all these other
microprocessors do everything that they can to make that happen
while keeping it nice and safe, which is pretty cool.
I mean you you know, you think about all the
work that they have to do in order for that
to to turn out that way. Well, there are lots
of different kinds of quadricopters, and if you do want
(28:26):
to make it turn like if you want to make
it bank one way or the other. Again, what happens
is it the quadricopter adjust the speed at which certain
rotors are spinning, so the lift changes exactly, Yes, the
lift changes and the torque changes, so the two together
can make you stray fit to the left or to
(28:47):
the right, or forward or backwards. I've even seen, I mean,
we've seen some that can do flips because what they'll
do is they'll is one side will spin very very
quickly while the other side stops spinning. It'll lift up
into the air, and then they'll switch the directions of
the rotors so that it flips it in mid air
and lands back, you know, right side up with all
(29:08):
rotors going, so it goes back into flying. And the
video that we were talking about at the very top
of this podcast, it was a little unnerving really because
we were seeing groups of these quadricopters that were all
following the same program, and you could have them grouped
into individual little squadrons, like squadrons of four quadricopters, and
(29:33):
I think there was something like, uh, they were using
twelve and all. So they had three groups of four
and they would send the three groups of four through
and through an obstacle course and they would maneuver past
each other, but they would all the four quadricopters would
move as a single unit, which was kind of creepy,
you know, to see something move like several small things
(29:54):
all moving together as one like that was a little odd.
And they can make a move through things like windows,
which was way griev er. Yeah, I got I got
these images of of drones coming into your house. Hello
Mr Smith, Yeah, we have something we'd like to say
to you, Oh skynet. Yeah, no, it's a yeah, your
(30:17):
water bill. While we hover around the topic of helicopters,
it's time for us to take another break to thank
our sponsor. So the video we're talking about specifically, and
I'll try and link to this when we do some
show notes, is called precise aggressive maneuvers for autonomous quad
(30:42):
quad rotors. Quadt I was gonna say quadrocopters but spelled
quad rotors and it totally threw me off. But this
was done through the GRASP Lab g r a s
P at the University of Pennsylvania. Yeah, that's a general
robotics Automation Sensing and Perception. Yeah, so this particular video
shows these uh, these tiny quadricopters moving through various maneuvers.
(31:07):
What's interesting here is that the one I'm looking at
right now, like it's this is one of those videos
that just got really popular all of a sudden, right
like that. Several of our listeners are watching listeners, um
are Yeah, but the video that I'm looking at right
now was uploaded so two years ago and we're just
(31:27):
now starting to catch on it. Sometimes the Internet is
a little slow to catch on the memes, That's what
I'm saying. But yeah, this was something that started to
make it make the rounds and uh and on Google
Plus and on Facebook recently and Twitter as well, and uh,
just one of those cool things that it turns out
it's been in the works for a few years, but
we just started to get the attention of the world
(31:48):
in general. But it shows a really interesting approach to
programming these quadricopters and showing their capabilities and what they
might be used for. And you might think, okay, well,
you know, you put a camera on these and then
suddenly you've got a spy plane. But you could also
have it for something like first responders. So there's a
(32:08):
let's say there's an accident and you send some of
these in uh that to in order to to scan
the scene and make sure that one it's safe enough
to send in an emergency response teams, and to whether
or not it's even necessary to start send an emergency
response teams. You may send in. Let's say there's a
building that's that's on fire, and you send some of
these over to look because I mean, these things, relatively
(32:31):
to a human life, are cheap. They're nothing. So you
can make as many of these as you like. They're
gonna be. They might be a little expensive, but it's
less expensive than losing a human life. So you send
these things in and take a look around. It may
turn out that, well, you know what, that building was
completely abandoned. There was no one in there, So we
don't need to risk the lives of any emergency responders.
We can just use the firefighters to try and put
(32:52):
this fire out. So that's the kind of idea that
we'd be looking at from that point forward. And there's
a lot of other possibilities, Um besides that. I mean
that's traffic, you know, having them look at traffic, things
like that. That's these are all possibilities. No, granted, you
have to figure out how to supply the power to
these things. Most of them are battery operated, and the
(33:14):
battery will only last so long. So it's not like
you would send out, you know, wake up, punch the clock,
send out fifty quadricopters to cover the city and then
at the end of the day they all come back. Uh,
So you know, it's not like it's a it's a
it's not like you can solve all the problems just
by sitting out quatricopters. But it's a cool idea and
(33:35):
the videos are pretty awesome. Also, the the the parrot videos,
those are really cool too because those have incorporated smartphone
applications and you can see through the camera. You can see. Yes,
you can use it as you can use as a
surveillance tool. Although it is it's whisperer quiet. I've used
that I've used that phrase like eight times on tech
(33:57):
stuff recently. But yeah, it's it's not like it's subtle.
It's you'll hear a when you're playing with one of
these things, but you can use it to look through
the camera. And they've even incorporated games into the drones
so that you can if you have one and your
friend has one, you're both controlling them with your smartphones.
You can play a game where you're essentially kind of
(34:18):
like laser tag but with drones. How awesome is that?
And then they also have other games where, uh, they'll
have targets show up on your screen. They're not they
don't actually exist in real life. It's an augmented reality
program where the targets appear on your screen and your
job is to fly your drone so that you can
use a little imaginary laser to shoot down these targets.
(34:40):
It's neat stuff like that, and it really, I mean,
beyond the fact that a quadricopter is pretty darn cool
by itself. Yeah yeah, yeah. As a matter of fact,
that one in particular also has some bumpers that it's
sort of be a shield for the for the rotors. Yes, yes,
so that you can fly it indoors. A lot of
uh model helicopters I've seen are are more traditional and
(35:04):
do not have that kind of protection for the rotors.
So you you wouldn't want to necessarily fly it around
your house even you want to bang into a lamp
or something. Yeah, even I've seen some of the small
ones that are pumped sort of palm sized. Um. But yeah,
I mean if if it actually touches something, it could
uh damage it or the copter or both, and that
that would be you could bang into someone serious. So
(35:26):
but yeah, the a r drone when the little bumpers
you're talking about, they look like little disks that fit
around like hollow disks. So yeah, they fit right around
where the rotors are. And so it kind of makes
us a safer device, so that if it were to
bump into something, you would just get bumped, you wouldn't
get cut. Yeah. Still you wouldn't want to get it
around people or or pets certainly. Um. So yeah, but
(35:51):
it makes it a little safer. Yeah, it's kind of neat.
And then uh, I've also heard from enthusiasts people who
really enjoy flying r C helicopters and r C quadricopters
that if you're interested in this, a quadricopter in general
tends to be a lot easier to fly because those
microprocessors I was talking about do a lot of the
(36:12):
fine tuning for you. So all you do is you
tell it I want you to go up, and it
takes care of the controls that needs to to make
those different rotors spin at the right speeds and makes
it go up or turn left or turn right or
straight or whatever. So it's it can be a lot
of fun and it can get people into the hobby
and it's not incredibly challenging. On the other hand, flying
(36:34):
a remote control helicopter requires a lot of finesse. Not
quite the same sort of thing you would need if
you were flying a life size helicopter, but still it
does require that you control things like the tail rotor
and that you're very methodical with the way that you
try and turn the helicopter, maneuver it, take off and landings.
(36:57):
It's it's actually, from why I understand one of the
more challenge ng RC vehicles to control, because there's just
so much you have to keep in mind. However, that
being said, even though it's really challenging, I also hear
it's one of the most enjoyable experiences, very rewarding because
once you master that, you know, you really have a
sense of accomplishment. So if you are interested in that
(37:18):
kind of hobby, I recommend you go ahead and you know,
check it out. See what, see what it would look.
How much it would cost to get into it, because
these these devices can be fairly expensive. Sometimes sometimes the
few hundred dollars is on the low end of some
of these devices. But it is something that if you're
interested in learning more about flight, if you're interested in
(37:39):
just kind of getting a new skill, it's kind of
a cool thing to get into. And uh, you know,
you know what, I've never actually written in a helicopter,
have you No, that's one of my goals I really
want to do. I want to do a hellic just
a simple helicopter tour. Nothing, nothing terribly you know, exciting.
I was thinking about actually doing one in Hawaii e
(38:00):
because I thought, well, heck, that would be amazing, you know,
the landscape and everything. But I happened to be married
to someone who finds air travel to be the uh
not the most relaxing experience, and so I didn't do that.
I did go parasailing though. Interesting. Yeah, totally not at
all like flying in a helicopter, I would imagine. Yeah,
(38:22):
I don't even know why I brought it up. All right,
So let's let's wrap this up. Guys. This was fun.
I'm glad we did this because, you know, we like
to try and tackle lots of different kinds of topics
here at tech Stuff. We like to talk about the
things that are a big social phenomena, you know, things
like like social networking sites and how technology affects us
(38:42):
personally or as a society. And we like to talk
about companies, and we like to talk about innovators. But
once in a while it's fun to take a specific
type of technology and really deconstructed and talk about the
various parts and what makes it go tick or fly
in this case. I hope you guys enjoyed that class episode.
If you have suggestions for future episodes of tech Stuff,
(39:03):
whether it's a technology, a company, maybe there's someone you
would like me to interview, why not right in? The
email address for the show is tech Stuff at how
stuff works dot com, or you can visit our website
over at tech stuff podcast dot com that has other
ways to contact the show, as well as a link
to our merchandise store, which is over at t public
dot com slash tech stuff. That's where you're gonna find
(39:24):
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