[uvc-youtube id=”d2mITQ53kr8″ width=”560″ height=”315″ autoplay=”0″ controls=”1″] Cyclic/collective pitch mixing is a mix bag of tricks.
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Can helicopter fly upside down, and how do the rotor blades adjust to the directional force of gravity. These questions and much more on this chopper wizard video.
Used in radio-controlled helicopters, Cyclic/collective pitch mixing (CCPM) reduces mechanical complexity and increases precision of control of the helicopter rotor‘s swashplate.
Conventional model helicopters use three independent servos to manipulate the swashplate. All three servos are used in varying amounts (i.e.: mixed) to tilt the swashplate forward and aft (longitudinal cyclic), varying the aircraft pitch, left and right (lateral cyclic), varying the roll.
To reduce the mechanical complexity of the helicopter, a CCPM system mixes the control inputs using software (usually running on the transmitter) and typically uses three interdependent servos to control the swashplate, with three linkages arranged around the swashplate at 120° intervals (there is a variation that uses 140° + 140° + 80° intervals). In addition to lower mechanical complexity, the interdependent servos share the workload. –wikipedia.
Cyclic/collective pitch mixing is a great challenge, in mastering a radio controlled helicopter.
Very, very cool footage.
Hey! Sorry but you looks like our Prime Minister of Slovak Republic – R. Fico 😀 Tottaly! 😀
It still seems that the wheels are moving backwards or not at all in modern commercials. Thank you physics for being able to explain things. 😀
2:59 …Look at that blade flex!! Gorgeous!
And the fact that he’s having the time of his life with his brain and the world.
Watched 3 of this guys videos. I think he should be appointed a cabinet level position on science education. Leadership, charisma, intelligence, and humility is a powerful combination.
haha, thats true too. ive crashed my r/c helis quite a few times and been able to walk away, lol.
This must be the most interesting and best explained Helicopter Series on the Internet. Many thanks for your work!
0:43 Lawn mowing like a boss 😀
The main reason real heli’s don’t do tricks like these is because to become this good you crash ALOT. Ask the pilot of that RC Heli if he ever crashed…..In most cases a real helicopter pilot only crashes once in his lifetime…..One crash usually kills you.
then there are the materials, trex uses carbon fiber vs. the apaches aluminum rotor blades. with the apaches rotor system turning at a mere 240 rpm, it cant achieve the rigidity needed to maintain inverted flight without striking the tailboom.
you really cant get a full scale heli to do all the stunts that a rc heli can do mainly becuase of structural integrity, not the pilot. you have to take into account the disk loading as well as the materials used and the size of the rotors. A Trex 600e weighing in at 3kg has a main rotor diameter of 1.35m, giving a disk loading of:3/(pi*(1.35/2)^2) = 2.1Kg/m^2. the AH64A Apache weighs in at 8000kg and has a rotor diameter of 14.63m, giving a disk loading of: 8000/(pi*(14.64/2)^2) = 47.5Kg/m^2
The heli simply isn’t giving you complete control of each of the components of the heli. More control, better stunts and tricks, but more skill needed to fly it safely and correctly.
Well, you first need to learn how to control it.
What RC Helicopter are you using ? I cant do anything like that with my syma SO 32. Great Videos; really interesting, well presented and informative.
“Meat servo = flight-stick actuator = pilot.” Greatest euphemisms ever.
What is the heli model?
It dosent blow my mind because I fly helicopters like that I hate walmart store pieces of krap and im trying to get my friend to fly helis but he thinks their stupied so im bumed out on that part ,yes im truing to get him to learn on a fixed pitch heli.
if you’re in a helicopter and it starts moving like this, your lifespan has just decreased to zero
Love this series and your videos in general. Thanks! Just wanted to say also that as far as I know almost all full scale helicopters aren’t capable of these kinds of manoeuvres. Loops and rolls in some rigid rotor systems, but otherwise the physics just don’t scale all that well with the materials available. RC models are extremely strong and powerful for their size/weight.
Do what you love man.
Hi, I am currently studying law in Malaysia and this is my final year. I’ve been watching this channel for the past 2 weeks and it reminded me of how exciting science can be. So i plan to pursue this field of study once i have completed my course.
the reason i am writing right now is to say thank you for all of great videos. it reminded me of what i truly love. So thank you very much!
Learned something thanks
In the middle of the upper half of the swashplate there is a metal ball with a hole milled through it that can rotate freely in any direction, the rotor shaft passes through this ball joint. This keeps the swashplate assembly fixed to the rotor shaft while allowing it to tilt freely in any direction and move up and down the shaft. You generally oil the shaft every 30-50 flights or so to keep the ball joint sliding freely.
There is a radial bearing between the upper and lower halves of the swashplate that allows the upper part to spin freely. That vertical bracket with the slot is called the anti rotation guide and prevents the lower half from spinning by means of a pin attached to the swashplate (this is usually an extension of the elevator ball link on most designs).
Probably more like $1500-$2500. You can actually get a pretty decent 600 class machine for around a grand. give or take a few hundred. For 10k you could have a turbine powered model helicopter (yes these exist)
For a first helicopter a 500 class machine is probably better, cheaper batteries, less expensive to fix when it crashes and still large enough to feel like a big heli. You can get a Trex 500E combo (i.e. has everything you need to build and fly except the radio system) for around $450
Meat Servo. MEAT SERVO!
That term, in and of itself, is deserving of several extra likes, and possibly a beer the next time I’m up yonder (I live outside Atlanta, and have been promising myself a trip to NASA Huntsville for the better part of 20 years now).
Even though his comment is welcome and should be encouraged (as it does promote learning), his claim that it is not aliasing is incorrect (as I’m sure you already knew as well, but just did not have the heart to tell him). He’s assuming that the term “aliasing” only includes “spatial aliasing”, and either doesn’t know or chooses to ignore “temporal aliasing”, which exactly describes the phenomenon that Mr. Evans is referring to.
Sorry to say Mr. Evans, but your claim that it is not aliasing is incorrect. What you’ve described is also considered aliasing, more specifically, TEMPORAL aliasing. So your claim that “they did not even have aliasing then because it was good old analogue film” is wrong. Temporal aliasing can occur in any time-discrete recording medium, analog or digital, including film cameras, because each instance is recorded frame-by-frame (which you correctly described, but incorrectly defined).
dear santa
Damn that is one expensive toy O_O has to have been about 10k or more…
Nice video finally someone to explain to people that helis can go inverted and it’s not fake.
One thing though in no case should you ever have a 700 size machine that close to you, Lol i got scared just watching that when he flew about five feet from himself inverted.
Other than that really good video.
Cool videos, however helicopter controls are easy, at least anyone with common sense knows how helicopter works. i didn’t know it was called swashplate tho, i just knew what controls the movement (in real helicopter it is controlled by the joystick in middle).
i dont even know who was the moron who said that real helicopter can’t go upside down or do a flip .. he must have been retarded .. a lot
isn’t this what we call common sense nowdays?? when he first said it on video, i was like .. huh .. why would he say something like that? to me it’s common sense, that something on video “stops” when framerate of camera matches the “framerate” of moving object.
Is this in anyway similar to when you look at a cars tyre with the human eye?
Your first reply was to:
“Did you know that the early western movies have the wagon wheels appear to go backwards or stop when they filmed them? They did not even have aliasing then because it was good old analogue film. The reason your rotor blades appear to stop is because the frame rate of the camera matched a multiple of the rotor speed. Aliasing in an effect that has to do with the rasterization of a progressive scan video and is responsible for the bent look of the blades.”
Oh, and a link to your preferred definition of Aliasing would be useful too. 😉
Oh, with 576 comments posted I had no idea you posted one earlier. Can you provide a link, (or paste the content), so I can see where the mistake lies, because from your reply here I can’t see that it’s mine. 🙂
What you are speaking of is what I described fully in my first post. This is not aliasing but an artifact of frame rates and synchronous events being recorded. I guess that you would have to have read my first post carefully and looked up the definition of aliasing to realize that you are wrong based on the wrong word being used to describe the phenomena.
Robert, even old films are subject to aliasing because they are made using 24 stills per second. Imagine a wagon wheel with 24 spokes. The stunt man drives the horses so that the wheel rotates precisely once every second. Between every still frame the wheel advances precisely by one spoke, so all the stills look the same and the wheel appears not to turn. If the stunt man slows just a bit, the wheel advances a bit less than one spoke per frame and the wheel looks like it’s going backwards. 🙂
Roll Tide!
thank you for doing all of the videos that you do they are very factual and have given me a new understanding of a lot of stuff.
I live in Destin! Florida that is (i’m not bacteria)
It is either the cobra or the apache chopper that was designed to do things like this. They had to fit special fuel tanks and pressurized oil tanks. There was a lot of work in making one do that kind of stuff without stalling or shutting down.
Due to gyroscopic precession, if the helicopter went upside down, wouldnt the angular momentum be pointing towards the ground? The rotation of the rotors would have to be flipped for the angular momentum to still be going upward, right?
I second your comment!
Thank you destin for helping me turn my procrastination into something useful. I am doing an experiment related with aerodynamics (mostly car related) and reading about similitude got me right on track. I was supposed to be reading about those things haha. (P.S this is my extended essay or the I.B diploma)
I encourage YouTube comments like these.
Did you know that the early western movies have the wagon wheels appear to go backwards or stop when they filmed them? They did not even have aliasing then because it was good old analogue film. The reason your rotor blades appear to stop is because the frame rate of the camera matched a multiple of the rotor speed. Aliasing in an effect that has to do with the rasterization of a progressive scan video and is responsible for the bent look of the blades.
Destin, this channel is simply the best on YouTube. I love you man! 🙂
IM OBSESSED WITH THIS SONG AND VIDEO
Watch episode 2 of this series
it still boggles my mind how the helicopter can fly upside down. I don’t know much about them but i do know that when the blades spin, it creates thrust, lifting the helicopter. but when he flips the helicopter over wouldnt that same thrust send it crashing down? unless he started spinning the blades in the opposite direction? I just dont understand it completely.
If you could respond to this I would appreciate it!
Nope. Bama.
This is completely on a whim, but you seem like an Auburn Engineer. Any chance I’m right?
Love this channel man…!
That’s called coincidence.
lol how ironic right now a helicopter flew above my house 😀
The “meat servo” (awesome name, btw) isn’t the only reason full-size helis cannot manoeuver like this; it’s also about the materials and the size and scale of energy. If you tried to do that with a real heli the blades, rotor head, rotor shaft, etc. would not survive. If you made a full-size heli out of super light-weight super-strong unobtanium then you could do this stuff — if you replaced the meat-servo with an RC human.
The blades push air down not only because of the direction they spin but also because of the pitch (angle) of the blades. When the pilot flips the heli upside down, he also reverses the angle of the blades so that they push air the other way.
Damn right getting smarter every day… No idea what most of this means.. IM … Why auto correct capitalized IM…. IM 13 years old…. But by knowing what the moment that is happening and what you are explaining I can figure mostly all of it out…
IM on a tablet… I CAN’T CLICK ON LINKS… FIND ANOTHER WAY…. CUZ I HAVE GOT no fuqing idea qwhat I r talking about…
The rotor head is speeding up and slowing down because the governor can keep the head speed constant at all times. It does a good job but is not perfect
there is a difference between being stupid and being ignorant. the south with the slavery thing and the bible belt – that is ignorance with a hefty dose of evil. of course not everybody is like that but it is an institution that is heavily concentrated in the confederate states
The angles of the blades are changed, not the direction they’re spinning in.
Don’t all the blades of the helicopter need to entirely reverse their spin direction to enable the helicopter to fly upside down? How does it work that the blades push air down to generate upward lift for the helicopter then when it goes upside down they push air… upward to generate upward lift? I’m so confused. How does this work.
What does that heli cost? 🙂
this series is awesome thanks for the work!
Thumbs up 🙂
i know a little bit about how a helicopter because of you Destin!
thank you 😀
WOOOOOOOOOOOOOOOOOOOOOOW , very nice videos and explanations
Wow!! I have to admit that I have never been referred to as a “Meat servo” before”
I love it. Great job. Lot of respect for you.