Mate, besides having the knowledge, which is absolutely respectable already, you are doing a great job at dumbing this down and explaining stuff, congratulations and thank you!
Years ago I when I was at a university I would stop over and help a helicopter mechanic who maintained emergency choppers for medical evacuation to the hospital. I am a master mechanic by trade. This was just a perfect place to unwind with a fellow mechanic. We worked together like frick and frack. I found out he passed away which bummed me out. But I still have memories working with him. He was trained in the military. May God have mercy on his soul. Peace vf
@@xiamalcami1878 he mentioned it's not controlled by the pilot. It just happens by itself via aerodynamic forces. (at least that's what I've gotten from this video)
I'm a helicopter pilot and everything described in that video was correct. The graphics show offset dual servo actuators moving the swash plate which is why all three servos need to move to achieve lateral and fore-aft tilt in the rotor system (this was animated correctly). To do that requires a mixing unit between the servos and the flight controls otherwise the pilot would have no hope of controlling the helicopter. This video was very well done.
I am an Emergency Physician, I am not a pilot, but I do fly fairly large RC helicopters as a hobby and have a fairly good understanding how this works, but these videos really put it in perspective at just how complex this stuff really is. My father flew the Bo 105 PAH-1 in the German Army and that machine used a different rotor head system. He used to tell me, a helicopter doesn't fly, it's a 10,000 bolt contraption that beats the air into submission while at the same time trying to self destruct. Thank you for this very informative video.
This was the most simplified version of the helicopter rotor function, and I've been searching to understand how it works. Finally, you did it, man.Thanks for making the man in the street learn.👏👍🏻😀🙌
I'm a layperson that flies in helicopters whenever the opportunity presents itself, such as helicopter tours, that sort of thing. I have never understood the mechanics of the rotors until now. This was an amazing video. I now have much better knowledge of these fascinating machines and I am going to watch the other videos you mentioned. Thanks for a great learning experience.
Came across your channel today and subscribed immediately. As a helicopter pilot, I see a lot of simplistic explanations as to how helicopter flight controls work. Yours is spot on and includes a mention of gyroscopic effects. Excellent. Well done!
Those who think it is animated incorrectly don't understand gyroscopic presession. Flight control inputs take about 90* of rotation before there is any change, so that is why the actuators are placed at 45* angles at the rear of the swash plate and the pitch arms are 90* to the blad itself. This allows the system to put in the correct angle of tilt at the right place for the blades to change pitch where needed. So if you want to fly forward you don't tilt the swash plate forward you tilt it forward right, this puts the high side of the swashplate aft left, and when the blade reaches dead aft 45* later(90*) it is in the position for forward thrust. Flight control rigging and main and tail rotor track and balance were two of the things that I did on multiple different helicopters in the Army and in the civilian sector.
The 120 degree swashplate and the angle between blades and blade actuators doesn't make it easier for people to understand. A simple 90 degree swashplate and no angle between blades and actuators would have been easier for people to understand. The 90 degree delay of gyroscopic presession could also easily have been explained. When I assembled my first RC heli I thought the manual was wrong because I didn't know about gyroscopic presession. Needless to say I had no control over the heli until I corrected my mistake ha ha.
@@dkjens0705 Even two bladed helicopters have the control horns at 45 degrees angles from dead aft or dead forward as this has to be done due to gyroscopic precession.
I think you have this stated incorrectly. Its not a matter of taking 90 degrees of rotation before there's any change. It's about gyroscopic precession; which is at 90 degrees to the force applied.
Fascinating, thanks for demystifying the business end of a helicopter for me, ive tried reading about it in books but your explanation and stages in animation were so much clearer! Thanks again.
As all always comprehensive and good visualized explained! Would welcome a vid about the different rotor systems from articulated to flex and mast bumping.
Thankyou for creating these videos my friend. Helicopters are very sophisiticated machinery, for beginners videos like these create a very simple understanding of very complex mechanical movements.
Wow, great rendering video of the flight control systems...Truly lost me, but closed my eyes and had to imagine the forces and the transfer of power to the blades...
Delightfully sophisticated design. I can only imagine the staggering amount of work, brain-power, and dedication, not to mention countless trials it must have taken, to get such a hair-brained concept to work half-way reliably and be commercially viable.
Don't get me wrong, the video, the animation and explanation are really good. But the notion of having large blades spin really fast, all the while controlled by high precision mechanisms, the entire assembly out in the open, susceptible to imbalance, constantly subjected to vibrations, is not particularly confidence inspiring. God forbid one of the many pins or joints or levers fails. Maintenance must be a nightmare.
I subscribed to this channel yesteday and I’m glad I did so that I could be notified of this video. So interesting. I finally understand why the controls are called collective and cyclic now 😅
Absolutely loved this video, thanks for putting in the hours. My only experience with helicopters have been calling in a pave low in mw2 and expertly piloting helicopters in battlefield 4 and 2042. Always wondered how these things worked, thank you 🤘🏽
what prevents the lift acting on the blade from pivoting them upwards at the flapping hinge, it seems like they would just become a rotating cone of blades unless there is a stop that I'm not seeing
Mechanically due to the pitch links they won't keep going up to that point. Like wings they are designed to take a certain amount of bending moment, and they begin to cone as collective is applied, when the system is at flight power and no collective is applied the blades fly at an angle called the "pre-cone angle" this is the blades producing enough lift for their weight but not yet enough to lift the helicopter off the ground. As the collective is increased the cone angle changes, and if the weight of aircraft exceeds the rating of the blades they can "egg beater", but this won't happen on the ground, you'll just run out of power(collective) and the blades will fly to a certain point and the drag they create will slow the whole system down, resulting in a low rotor RPM state and over torquing the system. Eggbeatering usually only happens if flight parameters exceed the limits of the system, such as if you are in a high speed descent, and you start to pull in collective, you aren't just trying to lift the weight of the helicopter but, you're also trying to arrest the momentum of the helicopter's movement as well, this can result in the blades snapping when they reach their limit and then looking like an old fashioned "eggbeater" to the outside observer. At this point the helicopter has the aerodynamics of a grand piano, and flies about as well, and there is nothing the crew can do to save themselves. This is usually the fault of the pilot and not the helicopter they have limits for a reason.
Fascinating stuff, thank you for producing such high quality information. Idea for a future video: Show how inputs from the cyclic/collective are transmitted to the 3 cylinders that act on the swashplate.
Watching this its mind-blowing to think how helicopter was first invented! Sikorsky was truly a genius! Thank you for your amazing animation and presentation!
I recently discovered your great work and really appreciate the the high quality of your animations and your clear narration in your voice. Apart from the informative material that garners real and honest interest from young people to old guys like me, the fact that you give it that personal touch and attention to detail absolutely compels me to not only subscribe but spread the word of your amazing channel. You good sir, have earned it. Thank you and keep it coming. I am 100% positive that you will inspire your viewers young and old alike, to consider careers in aviation, engineering, and other fields where we need brilliant minds to pave the way towards a technological future that we haven’t yet imagined!
Heli’s are always a blast to watch! I’m sure the engineering is phenomenal to say the least but to me all I see is a bunch of spindly parts, plates, hinges and turnbuckles spinning so fast! What could possibly go wrong!😵💫😂
ive been in helos 20 yrs as a mechanic and found this to be the easiest explanation ive found. i would love to see a video on their explanation of gyroscopic procession as for as input goes. this has far reaching theory in that large heavy bikes are steered the same way. @@bzig4929
Drive scissors and stationary scissors, these were the missing links in my understanding of helicopter control. Pity that the latter was missing in the animation - but at last I got my head wrapped around that stuff, thank you!
Very useful, thank you. Some of us need to know how in the hell something works, so we know why we need to do what we must do. I know there are folks who can learn to do stuff by just copying and following orders, but I ain't one of those! Thanks again.
I can relate to that. I've had a few employers tell me I ask too many questions about how something works. I'm an electrician, a really old one. Curiosity didn't kill the cat, it built a spaceship.
Hello I’ve been a helicopter maintenance technician and technical instructor for a number of years and your videos are excellent. However, to explain the helicopter flight control system, I suggest in using a two-blade rotor system and a swashplate with a 90° control input regime rather than a swashplate having 120°. For students it would be easier to understand the influence of the gyroscopic precession on the flight controls. Keep up the good work!
Thanks for the feedback! I'm working on a 4 blade model for the exact reason you say... It's easier to see and understand things like forward flight disymetry of lift and precession
@@bzig4929 Sounds great! I have suggestion for another project. Students often have a problem understanding the functioning of a so called “phasing unit”. For example, such a unit is installed in the flight controls of a Super-Puma. The unit rephases the 90° cyclic input signals to the 120° regime required by the swashplate. It would be great to have an instruction video showing the concept.
So when we do cyclic inputs all those lead leg flapping comes with feathering right? On the 8:00 since you did feathering flapping lead leg one at a time. There is no other control that caused flapping or lead leg right ?
Awesome video. I'd love to see how the internals of the rotating swasplate actually rotates around the NON-rotating swasplate/spherical bearing, as well as the internals of how the up/down motion of the spherical bearing moves relative to the transmission adapter... ( In short, all of the bearing surfaces that make everything in that general area move smoothly (bearings, seals, etc). A deep look within that whole area ). Again, great video. Thanks for sharing.
I want to see further what thickness is the axle shaft on which all this is attached, the axle shaft that lifts the entire helicopter, the main load goes on it
I love helicopters. I've only been in one once, but it was from Oakland airport to SFO at like 50 feet above the bay, it was unreal. Later I took up RC cars, boats, planes and finally helis and the learning curve was a wall. To turn left, you think about it and it responds, moving the stick = crash. Only the rudder needs some input, and too much is wheeeee! From what I've seen, the full-size ones are similar, like pushing over a domino is enough pressure. 3D flying 450's are bonkers.
As far as I understand, EC-135 doesn't have any of these hinges (except feathering) and it still flies, is quite controllable, stable and doesn't vibrate. How come?
Clear, concise and easy to understand explanation for a rather complex system, though I don't know how meaningful that statement is, since I am a trained industrial mechanic. One thing however that I either didn't understand or was missing from the animation/explanation was how flapping is "controlled". As you said it's entirely determined by aerodynamics and inertia but I would assume that the hinges that facilitate that motion have a neutral position and that there is some sort of spring element that tries to return the blades to that position. Just like the spring element for lead lag.
My vision with this is to do a series of videos that build on each other. The reason flapping and lead-lag exist are very specific and deserve a good explanation. I'm also trying to grow my animation skills and I need to learn how to do on-screen annotations for those topics. For the short answer... Flapping exists to correct for "forward flight dysemmetry of lift" and to allow control by tilting the tip path plane. Lead-lag allows for conservation of angular momentum as the blades flap asymmetrically. I love comments like yours! They really help me make the next videos better. Thanks.
i disagree Arne. the blade pitch is incredibly stable. due to Aerodynamic Twisting Moment, all the blades will want to increase pitch automatically. this is easily witnessed when dropping a piece of paper vertically. it wants to turn flat into the air in direction its moving. It when you want to change that pitch to something else is when CTM & ATM come into play, so yes, alot more force is required to get them to move. @@ArneChristianRosenfeldt
@@michaelgeorge3092 I did only consider rigid bodies. Around which axis do the blades pitch? I know that some blades have a stable airfoil like a flying wing. But I ( for RC or drone ) would minimize blade weight and optimize for Lift only. A flying wing with a straight leading edge better has it made of steel. I think that helicopter blades have knife edge to cut through small branches and birds?
This is all fascinating. The blade pitch control (collective and cyclic) is clear, but what is the purpose of the lead/lag and the feathering? and how is feathering restrained when under load?
that's my next video! I've started the story line and script and, once that's done, I'll start creating the video clips. Even though I'm reusing the same solid model, there is quite a bit of work to do to get them ready. In short... flapping allows the helicopter to fly fast and also allows control. But when it flaps the individual blade center's of gravity shift and this would create a problem with conservation of angular momentum... and this is what the lead-lag hinge solves. Constraining feathering under load... that's interesting... the blade pitch is close to the aerodynamic center, so loads are as low as they can be, but still significant. The answer, I believe, is robust components and lots of hydraulic pressure.
with these different materials of steel has to be semi-rigid right? how much wind speed can it withstand during sandstormy plus freezing rain of hails everywhere weathers? or just do not fly when bad weathers are around as the end scenario... so as to avoid accidents at all...
good question... when rotating, the CF loads keep them from drooping or flapping excessively. As you shutdown the rotors, there is a spring loaded droop-stop that moves into position (moves in under spring tension, moves out under CF loads). If the droop stop malfunctions, the rotor won't be damaged as it would just come to rest against the limit of travel of the flap hinge... unless the blade hits another part of the aircraft as it's coasting to a stop. Droop stops are painted bright colors so a crew-chief, outside the aircraft, can visually check when they go in. Some aircraft procedures have the pilots pull the engines back to idle prior to shutdown for the purpose of getting confirmation that the droop stops are seated. I didn't animate the droop stops.
wait, but what limits the flap in a hinged system? like why don't they droop on the ground, or flip up when lift is applied? is that just based on centrifugal forces?
Yes... CF loads. What's cool is that the CF loads increase as the blades flap away from neutral so it's a heavily damped system. Meaning that even aggressive maneuvering is unlikely to overlap the Rotors. My animation is greatly simplified and real helicopters have flap stops that are there for low rpm... Startup and shutdown. The stops are spring loaded so they are only in place at low CF (low RPM). if the blades were to contact a stop at high RPM - they can't because the CF loads overcome their spring force, and move them out of the way - but if they did, they would not protect the rotor. Loads are too high at flight RPM.
So, how is flapping "controlled"? What's stopping the blades from just folding upwards with the lift? It can't just be the centrifugal force, can it? Are those hinges spring loaded and damped somehow?
It's just CF and the damping from the CF is sufficient that flapping doesn't need any springs or dampers. This doesn't address droop (negative flapping) when the rotors stop... This is handled with a mechanical droop stops that I didn't model in this simplified CAD model. Thanks for the question. I want to do a video on this exact subject... My day job keeps getting in the way.
Great stuff man! I'd love to see a video similar to this but with a semi rigid rotor system. (this model seems to based off a blackhawk or similar, right?) Been working as a helicopter CFI and your videos are great to explain to students how all the concepts tie together
Cool idea on the semirigid rotor! I'll need to figure out how to bend objects in the animation software. The main rotor, in this vid, is modeled after a ch-46, but the tail rotor and tail rotor drive is modeled after the S-92/Blackhawk. I had already done a ch-46, so I just copied that main rotor instead of creating a new one. The hawk also has the engine further forward with a nose gearbox... So the main transmission is also a little different.
This is key element of helicopter stability. And it was invented by Igor Sikorsky in 1926 year in the USA after several years of work with different prototypes of helicopter, which were not stable enough in flight. He started his inventions in Kyiv Polytechnical Institute, Ukraine, which is titled by his name.
I'm curious why the lead/lag is accomodated for rather than an attempt to eliminate it. Are the forces involved just too much stress to restrain? I'm also curious how the non rotating swashplate is fastened to the spherical bearing. I see there are a ring of bolts surrounding it which leads me to surmise that the bottom half (if it is in-fact two pieces) is sent down the transmission adapter first, followed by the bearing, then capped with the top half clasping them all together, is this correct? Fantastic breakdown as always.
The lead-lag degree of freedom can be eliminated with a type of rotor called a teetering rotor. In a teetering rotor, flapping occurs very close to the center of rotation. In the rotor system I animated, the flapping hinge is offset from the center of rotation and this causes two things that make a lead lag hinge necessary. The first is to relieve out-of-plane rotor forces when the rotor disk tilts on its virtual axis. This is due to Coriolis effect. The second reason is to allow for conservation of angular momentum. When the blades flap, their CG also moves inward. Much like an ice skater spins faster when she moves her arms inward, helicopter blades must spin faster when the flap away from neutral... The lead-lag hinge allows them to spin faster for the half cycle where they flap away from neutral, followed by spinning slower as they flap back towards neutral. Blades that don't lead-lag are called "stiff in plane" and these designs are possible, but not good for structural life of the blades.
What I have not understood is the rotation of the blade, am seeing it running in an ant clock direction, is it ok or it must run in a clock wise direction
Q: Why are most helicopters have four or five rotor blades? Can they build them to have 9 or 12 blades (multiple of 3s) because they can outperform some other fewer blades in term of lifting forces? Did any companies ever tested with such a more complexity by having a higher number of blades?
That concept is called "solidity". It's the ratio of the solid planform area of the rotor disk, to the empty platform area. Generally, for higher gross weight, you want higher solidity. So wider chord blades or more of them. I think the limiting factor to more-blades will be fitting the rotor controls into the narrowing space between the blades. The most blades is 7 on the ch53 and mi26. I could be wrong.
Awesome. Would be nice to simulate and animate flight conditions (in-flight direction/pitch) to control system input. Why would blade lead lag be needed.
Hi mate, I’m curious to know how the flight controls are connected to the rotors. What I’m asking is, when pilots make an input on the cyclic or collect, what mechanism drives the input to the rotors to perform the input. Is it a combination of wires, hydraulics or something complete different. I’m struggling to find any answers online. Thanks!
Good question! When you see how complicated these are, you'll understand why I didn't include that in the animation. If you do an image search on "helicopter mixing unit" you'll see what I mean. The complexity comes because each control on the flight deck has to influence all three hydraulic actuators, so they all have to get mechanically mixed before they connect to the pilot valves. And larger helicopters also do some non-traditional control mixing. The canted tail used in many Sikorsky aircraft would case a pitch change with pedal input if it were not dealt with at the design... So they mix in longitudinal cyclic commands with the pedal inputs. I may tackle the mechanical controls for a future animation, but it's a daunting task.
outstanding tutorial. was hoping you would chose the uh-60 rotorsystem for demonstration instead. but here a question: who was inventing this concept in the first place? is that known?
One of the other commenters told me of Boris Yuryev who used swashplates in a helicopter design in 1912. I had no idea the technology had been around that long. The history of science and technology is so cool... It's amazing to think of what mankind accomplished without the modern design tools we have today.
my words! would be interesting to close the gap between leonardo da vincis time and 1912, understand what was the actual momentum of innovation. love your channel by the way. not sure why youtube has directed me to you only now.@@bzig4929
Mate, besides having the knowledge, which is absolutely respectable already, you are doing a great job at dumbing this down and explaining stuff, congratulations and thank you!
Thanks! I appreciate that comment more than you know.
I just found this channel. This is great
@@bzig4929you have done an awesome job, sincerely grateful ❤
Dumbing down is relative. I need dumber.
I was a helicopter mechanic for 30 years. Well explained. Most people do not understand any of this.
Years ago I when I was at a university I would stop over and help a helicopter mechanic who maintained emergency choppers for medical evacuation to the hospital. I am a master mechanic by trade. This was just a perfect place to unwind with a fellow mechanic. We worked together like frick and frack. I found out he passed away which bummed me out. But I still have memories working with him. He was trained in the military. May God have mercy on his soul. Peace vf
The flapping is not clear where the connection to flap the propeller.
@@xiamalcami1878 he mentioned it's not controlled by the pilot. It just happens by itself via aerodynamic forces. (at least that's what I've gotten from this video)
@jmackswb I have a doubt whether you have understood or not.
I'm a helicopter pilot and everything described in that video was correct. The graphics show offset dual servo actuators moving the swash plate which is why all three servos need to move to achieve lateral and fore-aft tilt in the rotor system (this was animated correctly). To do that requires a mixing unit between the servos and the flight controls otherwise the pilot would have no hope of controlling the helicopter. This video was very well done.
I am an Emergency Physician, I am not a pilot, but I do fly fairly large RC helicopters as a hobby and have a fairly good understanding how this works, but these videos really put it in perspective at just how complex this stuff really is.
My father flew the Bo 105 PAH-1 in the German Army and that machine used a different rotor head system.
He used to tell me, a helicopter doesn't fly, it's a 10,000 bolt contraption that beats the air into submission while at the same time trying to self destruct.
Thank you for this very informative video.
Mechanics, students, and instructors everywhere are going to use these videos. They are incredible!
thanks!
This was the most simplified version of the helicopter rotor function, and I've been searching to understand how it works. Finally, you did it, man.Thanks for making the man in the street learn.👏👍🏻😀🙌
看完视频我感觉能制造了😂
I'm a layperson that flies in helicopters whenever the opportunity presents itself, such as helicopter tours, that sort of thing. I have never understood the mechanics of the rotors until now. This was an amazing video. I now have much better knowledge of these fascinating machines and I am going to watch the other videos you mentioned. Thanks for a great learning experience.
Came across your channel today and subscribed immediately. As a helicopter pilot, I see a lot of simplistic explanations as to how helicopter flight controls work. Yours is spot on and includes a mention of gyroscopic effects. Excellent. Well done!
The movements of the two joysticks in the cabin wrapped it up neatly. They show how the pilot controls the rotor mechanisms. Great video.
Love the science behind it and the simplified mechanics. Answers my curiosity.
Those who think it is animated incorrectly don't understand gyroscopic presession. Flight control inputs take about 90* of rotation before there is any change, so that is why the actuators are placed at 45* angles at the rear of the swash plate and the pitch arms are 90* to the blad itself. This allows the system to put in the correct angle of tilt at the right place for the blades to change pitch where needed. So if you want to fly forward you don't tilt the swash plate forward you tilt it forward right, this puts the high side of the swashplate aft left, and when the blade reaches dead aft 45* later(90*) it is in the position for forward thrust. Flight control rigging and main and tail rotor track and balance were two of the things that I did on multiple different helicopters in the Army and in the civilian sector.
Sorry I read your comment wrong😅 my mistake
Well said sir!! Isn’t this an amazing channel?? I love the fact that you back him up with real knowledge and experience. Right on!!
The 120 degree swashplate and the angle between blades and blade actuators doesn't make it easier for people to understand. A simple 90 degree swashplate and no angle between blades and actuators would have been easier for people to understand. The 90 degree delay of gyroscopic presession could also easily have been explained. When I assembled my first RC heli I thought the manual was wrong because I didn't know about gyroscopic presession. Needless to say I had no control over the heli until I corrected my mistake ha ha.
@@dkjens0705 Even two bladed helicopters have the control horns at 45 degrees angles from dead aft or dead forward as this has to be done due to gyroscopic precession.
I think you have this stated incorrectly. Its not a matter of taking 90 degrees of rotation before there's any change. It's about gyroscopic precession; which is at 90 degrees to the force applied.
Fascinating, thanks for demystifying the business end of a helicopter for me, ive tried reading about it in books but your explanation and stages in animation were so much clearer! Thanks again.
Im not a pilot. Im an “ aviation enthusiast “. Ive watched other videos, but this one actually made it the most understandable for me. Thank you! 👍🏽
As all always comprehensive and good visualized explained!
Would welcome a vid about the different rotor systems from articulated to flex and mast bumping.
Excellent! I've been searching for a video that clearly shows how the swash plate mechanism works. Finally found it.
Thankyou for creating these videos my friend. Helicopters are very sophisiticated machinery, for beginners videos like these create a very simple understanding of very complex mechanical movements.
Wow, great rendering video of the flight control systems...Truly lost me, but closed my eyes and had to imagine the forces and the transfer of power to the blades...
I'm always amazed that all of this stuff can hold together when under load and not disintegrate into a million pieces.
Note at 3:20 that a single shaft keeps the entire contraption in the air. How can that not make an impression?
Delightfully sophisticated design. I can only imagine the staggering amount of work, brain-power, and dedication, not to mention countless trials it must have taken, to get such a hair-brained concept to work half-way reliably and be commercially viable.
Don't get me wrong, the video, the animation and explanation are really good. But the notion of having large blades spin really fast, all the while controlled by high precision mechanisms, the entire assembly out in the open, susceptible to imbalance, constantly subjected to vibrations, is not particularly confidence inspiring. God forbid one of the many pins or joints or levers fails. Maintenance must be a nightmare.
this channel is a pure gold mine! thanks!!
Really interesting & clearly illustrated and explained. 👏👏👏
Glad you liked it!
I subscribed to this channel yesteday and I’m glad I did so that I could be notified of this video. So interesting. I finally understand why the controls are called collective and cyclic now 😅
Welcome back!
Absolutely loved this video, thanks for putting in the hours. My only experience with helicopters have been calling in a pave low in mw2 and expertly piloting helicopters in battlefield 4 and 2042. Always wondered how these things worked, thank you 🤘🏽
I'm not sure, but I think the software I use (blender) is used to make assets for gaming.
what prevents the lift acting on the blade from pivoting them upwards at the flapping hinge, it seems like they would just become a rotating cone of blades unless there is a stop that I'm not seeing
Short answer is... The centrifugal force loads as the blades rotate. I'm planning a future video to show the details on that. Thanks for watching!
Mechanically due to the pitch links they won't keep going up to that point. Like wings they are designed to take a certain amount of bending moment, and they begin to cone as collective is applied, when the system is at flight power and no collective is applied the blades fly at an angle called the "pre-cone angle" this is the blades producing enough lift for their weight but not yet enough to lift the helicopter off the ground. As the collective is increased the cone angle changes, and if the weight of aircraft exceeds the rating of the blades they can "egg beater", but this won't happen on the ground, you'll just run out of power(collective) and the blades will fly to a certain point and the drag they create will slow the whole system down, resulting in a low rotor RPM state and over torquing the system. Eggbeatering usually only happens if flight parameters exceed the limits of the system, such as if you are in a high speed descent, and you start to pull in collective, you aren't just trying to lift the weight of the helicopter but, you're also trying to arrest the momentum of the helicopter's movement as well, this can result in the blades snapping when they reach their limit and then looking like an old fashioned "eggbeater" to the outside observer. At this point the helicopter has the aerodynamics of a grand piano, and flies about as well, and there is nothing the crew can do to save themselves. This is usually the fault of the pilot and not the helicopter they have limits for a reason.
Fascinating stuff, thank you for producing such high quality information.
Idea for a future video: Show how inputs from the cyclic/collective are transmitted to the 3 cylinders that act on the swashplate.
Good suggestion! Also a challenge... helicopter mixing units are gloriously complex things.
Thank you for your work. Well done.
Watching this its mind-blowing to think how helicopter was first invented! Sikorsky was truly a genius! Thank you for your amazing animation and presentation!
These videos are such high quality great job explaining it mate love the videos 😁
I recently discovered your great work and really appreciate the the high quality of your animations and your clear narration in your voice. Apart from the informative material that garners real and honest interest from young people to old guys like me, the fact that you give it that personal touch and attention to detail absolutely compels me to not only subscribe but spread the word of your amazing channel. You good sir, have earned it. Thank you and keep it coming. I am 100% positive that you will inspire your viewers young and old alike, to consider careers in aviation, engineering, and other fields where we need brilliant minds to pave the way towards a technological future that we haven’t yet imagined!
Thanks so much for those very nice words!
Heli’s are always a blast to watch! I’m sure the engineering is phenomenal to say the least but to me all I see is a bunch of spindly parts, plates, hinges and turnbuckles spinning so fast! What could possibly go wrong!😵💫😂
It's complicated enough! However thanks for the explanation
Fantastic, keep those reruns coming. Fantastic
I'm an aeronautical student from Kenya and I find your videos very useful
I'm glad you find them useful. Thank you for watching!
I've been a helicopter for 42 years. This information is correct
Thanks! Much appreciated coming from someone with your experience!
ive been in helos 20 yrs as a mechanic and found this to be the easiest explanation ive found. i would love to see a video on their explanation of gyroscopic procession as for as input goes. this has far reaching theory in that large heavy bikes are steered the same way.
@@bzig4929
Borrowed from the Roger Rabbit film: "I've been a cab for 40 years!"
Drive scissors and stationary scissors, these were the missing links in my understanding of helicopter control. Pity that the latter was missing in the animation - but at last I got my head wrapped around that stuff, thank you!
This is the best video İ have seen on this topic.
Thanks!
finaly I know why it is collective and cyclic controls ..thaks great video
A few people have said this! I'm glad I was able to help people make that connection.
Man your videos are incredible. Thank you for these.
Thanks!
This is really a great video. Very few explanations like this exists in the internet. Keep up the good work.
Thank you!
This is incredible and the exact thing I was looking for recently. I hope you'll do a comparison with the semi-rigid and rigid systems too!
Very useful, thank you. Some of us need to know how in the hell something works, so we know why we need to do what we must do. I know there are folks who can learn to do stuff by just copying and following orders, but I ain't one of those! Thanks again.
I can relate to that. I've had a few employers tell me I ask too many questions about how something works. I'm an electrician, a really old one. Curiosity didn't kill the cat, it built a spaceship.
Congratulations. Phenomenal explanation. Kudos and thank you.
Glad it was helpful!
Great Animation. Amazing
Hello
I’ve been a helicopter maintenance technician and technical instructor for a number of years and your videos are excellent. However, to explain the helicopter flight control system, I suggest in using a two-blade rotor system and a swashplate with a 90° control input regime rather than a swashplate having 120°. For students it would be easier to understand the influence of the gyroscopic precession on the flight controls.
Keep up the good work!
Thanks for the feedback! I'm working on a 4 blade model for the exact reason you say... It's easier to see and understand things like forward flight disymetry of lift and precession
@@bzig4929 Sounds great! I have suggestion for another project. Students often have a problem understanding the functioning of a so called “phasing unit”. For example, such a unit is installed in the flight controls of a Super-Puma. The unit rephases the 90° cyclic input signals to the 120° regime required by the swashplate. It would be great to have an instruction video showing the concept.
So when we do cyclic inputs all those lead leg flapping comes with feathering right? On the 8:00 since you did feathering flapping lead leg one at a time. There is no other control that caused flapping or lead leg right ?
Thanks fot feeding me with this content
Awesome video! I’ve always wanted to know how helicopters were controlled.
Awesome video. I'd love to see how the internals of the rotating swasplate actually rotates around the NON-rotating swasplate/spherical bearing, as well as the internals of how the up/down motion of the spherical bearing moves relative to the transmission adapter... ( In short, all of the bearing surfaces that make everything in that general area move smoothly (bearings, seals, etc). A deep look within that whole area ).
Again, great video. Thanks for sharing.
I want to see further what thickness is the axle shaft on which all this is attached, the axle shaft that lifts the entire helicopter, the main load goes on it
Excellent presentation !! Thank you.
Awesome lessons!
Wow ! Deep ! Guess I’ll just marvel at them flying !
Now I’m more interested in knowing what the cyclic and the collective effect are and this was very helpful
Good animation, tks for the video
We need explanation about the pedals and the cable witch is connected to the tail rotor and the movement of pedals
Absolutely outstanding. Can you teach me about droop stops and why they are used?
I've been playing a future video on the aerodynamic reasons for flapping and lead lag. Droop stops will be part of that! Thanks for commenting.
Simply awesome.
I love helicopters. I've only been in one once, but it was from Oakland airport to SFO at like 50 feet above the bay, it was unreal. Later I took up RC cars, boats, planes and finally helis and the learning curve was a wall. To turn left, you think about it and it responds, moving the stick = crash. Only the rudder needs some input, and too much is wheeeee! From what I've seen, the full-size ones are similar, like pushing over a domino is enough pressure. 3D flying 450's are bonkers.
Nice videos !
Was wondering if you could do one on the synchronization gear of a Messerschmitt Bf 109E1?
I had no idea they still used those in WWII! I found some photos online, but nothing that detailed. I'll keep looking.
As far as I understand, EC-135 doesn't have any of these hinges (except feathering) and it still flies, is quite controllable, stable and doesn't vibrate. How come?
Excellent explanation and animation.
Thank you.
Very nicely explained Sir. 😀😀😀😀
Thanks so much for your efforts brother
Bro, I see your future that you will be the second Lesics🎉
good work mate ❤
Thanks ✌️
Please discuss elastomeric bearings
Excellent!
Very well made and explained. So many moving parts, never get me in Helicopter. 😅
Clear, concise and easy to understand explanation for a rather complex system, though I don't know how meaningful that statement is, since I am a trained industrial mechanic. One thing however that I either didn't understand or was missing from the animation/explanation was how flapping is "controlled". As you said it's entirely determined by aerodynamics and inertia but I would assume that the hinges that facilitate that motion have a neutral position and that there is some sort of spring element that tries to return the blades to that position. Just like the spring element for lead lag.
My vision with this is to do a series of videos that build on each other. The reason flapping and lead-lag exist are very specific and deserve a good explanation. I'm also trying to grow my animation skills and I need to learn how to do on-screen annotations for those topics. For the short answer... Flapping exists to correct for "forward flight dysemmetry of lift" and to allow control by tilting the tip path plane. Lead-lag allows for conservation of angular momentum as the blades flap asymmetrically. I love comments like yours! They really help me make the next videos better. Thanks.
I wonder how high the friction is between rotating and non-rotating swashplates
It is a ball bearing. And I think that the swashplate is unstable and wants to tilt. So the more cyclic you apply , the more force and friction.
i disagree Arne. the blade pitch is incredibly stable. due to Aerodynamic Twisting Moment, all the blades will want to increase pitch automatically. this is easily witnessed when dropping a piece of paper vertically. it wants to turn flat into the air in direction its moving. It when you want to change that pitch to something else is when CTM & ATM come into play, so yes, alot more force is required to get them to move.
@@ArneChristianRosenfeldt
@@michaelgeorge3092 I did only consider rigid bodies. Around which axis do the blades pitch? I know that some blades have a stable airfoil like a flying wing. But I ( for RC or drone ) would minimize blade weight and optimize for Lift only.
A flying wing with a straight leading edge better has it made of steel. I think that helicopter blades have knife edge to cut through small branches and birds?
Thanks man real help for my autocad project
Awesome. I did this in Autodesk Fusion. Good luck with your project.
@@bzig4929 Fusion..Nice..Actually I had to make a 2d assembly of the swashplate thing.
This is all fascinating.
The blade pitch control (collective and cyclic) is clear, but what is the purpose of the lead/lag and the feathering? and how is feathering restrained when under load?
that's my next video! I've started the story line and script and, once that's done, I'll start creating the video clips. Even though I'm reusing the same solid model, there is quite a bit of work to do to get them ready.
In short... flapping allows the helicopter to fly fast and also allows control. But when it flaps the individual blade center's of gravity shift and this would create a problem with conservation of angular momentum... and this is what the lead-lag hinge solves.
Constraining feathering under load... that's interesting... the blade pitch is close to the aerodynamic center, so loads are as low as they can be, but still significant. The answer, I believe, is robust components and lots of hydraulic pressure.
This is v well done. Very impressive explanation but also sharp and clear graphics. Can I ask what you use for the graphics/3d modeling?
I use Autodesk Fusion for 3d modeling, and then I import the models into Blender for materials, lighting and animation. Thanks for watching!
I need guidance on compressor wash of an mi-24 helicopter
This is an incredible video!
You sir are a master of your craft
with these different materials of steel has to be semi-rigid right?
how much wind speed can it withstand during sandstormy plus freezing rain of hails everywhere weathers?
or just do not fly when bad weathers are around as the end scenario... so as to avoid accidents at all...
so... what prevents the blades from drooping along the flapping hinge when not rotating ?
good question... when rotating, the CF loads keep them from drooping or flapping excessively. As you shutdown the rotors, there is a spring loaded droop-stop that moves into position (moves in under spring tension, moves out under CF loads). If the droop stop malfunctions, the rotor won't be damaged as it would just come to rest against the limit of travel of the flap hinge... unless the blade hits another part of the aircraft as it's coasting to a stop. Droop stops are painted bright colors so a crew-chief, outside the aircraft, can visually check when they go in. Some aircraft procedures have the pilots pull the engines back to idle prior to shutdown for the purpose of getting confirmation that the droop stops are seated.
I didn't animate the droop stops.
I loved this vid thx you so much for all that hard work on it
Glad you enjoyed it!
wait, but what limits the flap in a hinged system? like why don't they droop on the ground, or flip up when lift is applied? is that just based on centrifugal forces?
Yes... CF loads. What's cool is that the CF loads increase as the blades flap away from neutral so it's a heavily damped system. Meaning that even aggressive maneuvering is unlikely to overlap the Rotors.
My animation is greatly simplified and real helicopters have flap stops that are there for low rpm... Startup and shutdown. The stops are spring loaded so they are only in place at low CF (low RPM). if the blades were to contact a stop at high RPM - they can't because the CF loads overcome their spring force, and move them out of the way - but if they did, they would not protect the rotor. Loads are too high at flight RPM.
So, how is flapping "controlled"? What's stopping the blades from just folding upwards with the lift? It can't just be the centrifugal force, can it? Are those hinges spring loaded and damped somehow?
It's just CF and the damping from the CF is sufficient that flapping doesn't need any springs or dampers. This doesn't address droop (negative flapping) when the rotors stop... This is handled with a mechanical droop stops that I didn't model in this simplified CAD model. Thanks for the question. I want to do a video on this exact subject... My day job keeps getting in the way.
Great stuff man! I'd love to see a video similar to this but with a semi rigid rotor system. (this model seems to based off a blackhawk or similar, right?) Been working as a helicopter CFI and your videos are great to explain to students how all the concepts tie together
Cool idea on the semirigid rotor! I'll need to figure out how to bend objects in the animation software. The main rotor, in this vid, is modeled after a ch-46, but the tail rotor and tail rotor drive is modeled after the S-92/Blackhawk. I had already done a ch-46, so I just copied that main rotor instead of creating a new one. The hawk also has the engine further forward with a nose gearbox... So the main transmission is also a little different.
@@bzig4929 Ah that's awesome, thanks for the clarification on the models it was based on!
This is key element of helicopter stability. And it was invented by Igor Sikorsky in 1926 year in the USA after several years of work with different prototypes of helicopter, which were not stable enough in flight. He started his inventions in Kyiv Polytechnical Institute, Ukraine, which is titled by his name.
fantastic video, very informed and detailed
When you see a large helicopter lifting a tank you appreciate how strong all those “delicate looking” connections must be.
I'm curious why the lead/lag is accomodated for rather than an attempt to eliminate it.
Are the forces involved just too much stress to restrain?
I'm also curious how the non rotating swashplate is fastened to the spherical bearing.
I see there are a ring of bolts surrounding it which leads me to surmise that the bottom half (if it is in-fact two pieces) is sent down the transmission adapter first, followed by the bearing, then capped with the top half clasping them all together, is this correct?
Fantastic breakdown as always.
The lead-lag degree of freedom can be eliminated with a type of rotor called a teetering rotor. In a teetering rotor, flapping occurs very close to the center of rotation.
In the rotor system I animated, the flapping hinge is offset from the center of rotation and this causes two things that make a lead lag hinge necessary.
The first is to relieve out-of-plane rotor forces when the rotor disk tilts on its virtual axis. This is due to Coriolis effect.
The second reason is to allow for conservation of angular momentum. When the blades flap, their CG also moves inward. Much like an ice skater spins faster when she moves her arms inward, helicopter blades must spin faster when the flap away from neutral... The lead-lag hinge allows them to spin faster for the half cycle where they flap away from neutral, followed by spinning slower as they flap back towards neutral.
Blades that don't lead-lag are called "stiff in plane" and these designs are possible, but not good for structural life of the blades.
@@bzig4929 excellent breakdown thankyou!
I hadn't considered that at all.
I read the book ' Chicken Hawk ' once so I'm almost a pilot. Fascinating read.😅
Fantastic video. Thank you.
What I have not understood is the rotation of the blade, am seeing it running in an ant clock direction, is it ok or it must run in a clock wise direction
It's the preference of the designer. I believe most main rotors turn counter clockwise, but there are more than a few that turn clockwise.
Q: Why are most helicopters have four or five rotor blades? Can they build them to have 9 or 12 blades (multiple of 3s) because they can outperform some other fewer blades in term of lifting forces?
Did any companies ever tested with such a more complexity by having a higher number of blades?
That concept is called "solidity". It's the ratio of the solid planform area of the rotor disk, to the empty platform area. Generally, for higher gross weight, you want higher solidity. So wider chord blades or more of them. I think the limiting factor to more-blades will be fitting the rotor controls into the narrowing space between the blades. The most blades is 7 on the ch53 and mi26. I could be wrong.
excellent video. Tell me what software do you use to produce such stunning graphics?
I use blender for materials, lighting and animation. I create the objects in Fusion 360.
youre a genius@@bzig4929
Awesome video!
Awesome. Would be nice to simulate and animate flight conditions (in-flight direction/pitch) to control system input. Why would blade lead lag be needed.
Hi mate, I’m curious to know how the flight controls are connected to the rotors. What I’m asking is, when pilots make an input on the cyclic or collect, what mechanism drives the input to the rotors to perform the input. Is it a combination of wires, hydraulics or something complete different. I’m struggling to find any answers online. Thanks!
Good question! When you see how complicated these are, you'll understand why I didn't include that in the animation. If you do an image search on "helicopter mixing unit" you'll see what I mean.
The complexity comes because each control on the flight deck has to influence all three hydraulic actuators, so they all have to get mechanically mixed before they connect to the pilot valves. And larger helicopters also do some non-traditional control mixing. The canted tail used in many Sikorsky aircraft would case a pitch change with pedal input if it were not dealt with at the design... So they mix in longitudinal cyclic commands with the pedal inputs.
I may tackle the mechanical controls for a future animation, but it's a daunting task.
RC helicopters just use electric motors to actuate. They have a digital mixer in the remote.
❤ thank you 🙏
Very well 👏 👌 presented
outstanding tutorial. was hoping you would chose the uh-60 rotorsystem for demonstration instead. but here a question: who was inventing this concept in the first place? is that known?
One of the other commenters told me of Boris Yuryev who used swashplates in a helicopter design in 1912. I had no idea the technology had been around that long. The history of science and technology is so cool... It's amazing to think of what mankind accomplished without the modern design tools we have today.
my words!
would be interesting to close the gap between leonardo da vincis time and 1912, understand what was the actual momentum of innovation. love your channel by the way. not sure why youtube has directed me to you only now.@@bzig4929
Thought you’d have a hundreds of thousands of subs. Great video.
I working to get there! Thanks for watching and commenting.
Could you do the C-5 Galaxy? It really help some of the new guys coming outta tech school. Especially hydro
Excelente video
Muchas gracias
Excellent presentation. Fascinating animations. (By no means a pilot, jus' sayin'.)