This would be so much fun! That solo platform looks pretty neat. I've seen an older variant of this that was fixed in place, but this looks like it would be more effective as a training aid. As always great videos buddy.
That's interesting, never seen one of those fixed but I also had never seen this crazy platform until I made that video haha. Pretty Crazy! Thanks! Glad you like the channel!
You mentioned autorotations in this coaxial helicopter. I'm wondering how yaw control works on this bird while in an autorotation? Under power, torque is being applied to both rotor masts. All you have to do to induce a yaw motion is unbalance the torque load between the two rotor systems and the fuselage will yaw in a direction opposite the rotor mast with the greater load. In a true engine out autorotation, there's no torque going to either rotor mast and thus, no torque reaction with which to induce a yaw command. Just posing the question out of curiosity.
Great question Steve! You raise a very good point and even had to do some research to find the answer, and learned something new so thanks! In a coax rotor when the engine is running, yaw is controlled by actually creating a difference in collective input to each of the separate rotors. So even though there is still obviously one collective, this difference in collective input is then controlled by the rudder pedals (best I know). This dance of difference in collective input to each of the two rotors is what gives an imbalance in torque between the rotors and thus your yaw control. ... but lose your engine and your are correct, no more torque input... thus no yaw control, something I had never realized! So maybe not so great for auto rotations after all 🤦♂️😂 There is some ability to maintain control however in a similar way if you lost your tail rotor in a conventional helicopter. More forward air speed will keep you straight by the air pushing the helicopter straight into the airflow. This is also why a lot of these helicopter have large vertical stabs (like this one having two) in the back, and even some of the large Russian ones I've seen with actual rudders to control this even more. I always thought these where just for extra yaw authority in the air, never realized they are also (and maybe its main purpose) for maintaining yaw control in autos. Thanks for the insight! Hope you like the show! -James
@@RelativeMotionCC - very interesting. I was thinking the vertical stabilizers at the back were mainly there to help stabilize things in cruise flight just like they do on a conventional helicopter. I'm not sure how effective they'd be at the bottom of an autorotation as you're going to be at pretty low airspeeds by the time you get to the ground so I'm not sure how effective they'd be but I'm sure they'd be better than nothing. I knew that the "rudder" pedals were inducing differential collective to control yaw. That much makes sense. I've been thinking about this and am wondering if this might be true. When you step on the rudder pedals, you're increasing collective on one rotor while decreasing it on the other. I imagine these are very small movements, maybe only fractions of a degree in most cases. Still, it seems to me that would change the drag profile between the two rotors and induce a yaw movement as a result. You're not going to be doing pirouettes this way but it may be enough to keep the nose pointed in the direction of travel over the ground at touchdown. At any rate, I've love to see a coaxial helicopter do an autorotation. What do you think?
@@RelativeMotionCC The section about “torque input “ is not correct…The 2 discs shafts get the same torque from the engine just turning opposite direction…there is no torque device in the transmission…both shafts gets the same rpm as well…I think. The mixer mechanically links the pilot controls with which you manipulate the AOA of the blades and this changes the forces on the 2 rotor discs separately (rudder-yaw) and/or at the same time (collective-updown, stick-pitch&bank) For autorotation rotor speed comes from “gliding”, the AOA and drag difference between the 2 discs to control yaw is still possible… To maintain gliding you need speed…The last phase when cushioning for impact we exchange extra inertia of blades thus energie into more AOA/lift to decrease sink rate and speed…
With what device would you "unbalance the torque load" from the engine??? It is easy to say it but to build it... mechanically you get a heavy complex transmission part...remember coaxial helicopters (Kamov) were successfully developed and deployed in the 1960s... So unbalancing must come from changing blade aerodynamics forces...in my logic...
@@electricaviationchannelvid7863 - I understand what you mean about the "torque input" comment. Probably not the proper way to put it. The engine is applying torque to spin both rotor systems but that doesn't mean the both rotor systems are absorbing the same amount of torque. If one rotor is carrying more collective than the other, then the one with the higher load with have the greater torque reaction and that's the way the fuselage will yaw. How they do this mechanically between the "rudder" peddles and the individual rotor systems is still magic to me. I've never had the opportunity to examine one up close. That's kind of why coaxial helicopters fascinate me so much, and it's why I've posed the questions I have here. I'm just trying to understand. I'm thinking we're probably close to being on the same page with regards to changing blade aerodynamic forces to control all this.
How do you perform dynamic rotor balance? E.g. How do you determine where to add wts on one rotor system vs the other? I've balanced single rotor machines and find it easy if it is done with the ship in a hover so that ship vibrations are isolated from the ground and subsequent ground effects.
I’ve never balanced a coaxial myself either… but I would imagine it’s similar, you just might need a special kind of vib. machine to track each rotor independently… rotor balance sure is complex so I hope to do a video more someday going more into this. Great question though!
@@RelativeMotionCC I think that there must be some way to isolate the vibration caused by one rotor system from that caused by the other. I tried a test with a DynaVibe by putting an known out of balance wheel on my Bridgeport mill. The results were all over the place. It seems the vibration caused by my test wheel would cause sympathetic vibrations in the machine and the balance indications would be erroneous. We repeated this test with a motor and wheel mounted on my heavy test bench. Same results. However, when testing on a hovering helicopter it worked like a charm. Is there a way to hover a coaxial ship with just one rotor? That would isolate out of balance vibrations to just the one rotor at a time.????
I would think the DynoVibe, microvibe, or whatever vibe machine it is, it needs specific software or a program for co axial because it’s going to have a much different vibration pattern than a normal rotor… so if you don’t have a that proper program I don’t think it would work. And no unfortunately I can’t imagine you could ever run a co axial with only one rotor head
@@RelativeMotionCC would be good to see a dynamic balancing video for a coaxial. I built a coaxial and balanced the rotors statically span-wise and chord-wise. They ran very smooth and no adjustments were necessary other than tracking. If I had vibration issues I wouldn't know where to start.
Talking about part 103 fuel capacity, i believe you can have multiple 5 gallon fuel tanks, but you need to land to switch them, they can't be switchable in the air, and that's legal.
@@RelativeMotionCC co-axial rotors can still maintain yaw control while auto rotating because of the change in drag on the blades when the angle of attack changes such as when you press a yaw pedal.
Remember the R22 is a certified machine with 2200 hrs max before very expensive refresh 70k but, your point is valid, I did have a Rotorway exec 47k cdn which flew well.
Mirocopter SCH-2A Small Coaxial Helicopter is for now the only FAR Part 103 compliant, weight < 115kg, and the smallest true coaxial helicopter in the world. Unfortunately, Rotorschmiede VA115 is not FAR Part 103 compliant, weight > 115kg, and is not the smallest true coaxial helicopter in the world.
That price is clearly in the ripoff bracket. I bought a functional Rotorway for 47k cdn. Flew it for four years then sold it only b/c it was a bit tight to sit in.
According to it's website it's certified, that alone is going to balloon the price to something crazy. Then add in the engineering and the machining involved in a coaxial, I'm not at all surprised it's expensive.
@@RelativeMotionCC Wait till you see Franz Schöfmann's coaxial (I've seen two, one petrol, one electric) ! I want to build one with a single rotor and an innovative simple solution for the rotor torque.
This would be so much fun! That solo platform looks pretty neat. I've seen an older variant of this that was fixed in place, but this looks like it would be more effective as a training aid. As always great videos buddy.
That's interesting, never seen one of those fixed but I also had never seen this crazy platform until I made that video haha. Pretty Crazy! Thanks! Glad you like the channel!
@@RelativeMotionCC What do you think of the products of this company?
ua-cam.com/video/xDYtsTigE2M/v-deo.html
You mentioned autorotations in this coaxial helicopter. I'm wondering how yaw control works on this bird while in an autorotation? Under power, torque is being applied to both rotor masts. All you have to do to induce a yaw motion is unbalance the torque load between the two rotor systems and the fuselage will yaw in a direction opposite the rotor mast with the greater load. In a true engine out autorotation, there's no torque going to either rotor mast and thus, no torque reaction with which to induce a yaw command. Just posing the question out of curiosity.
Great question Steve! You raise a very good point and even had to do some research to find the answer, and learned something new so thanks!
In a coax rotor when the engine is running, yaw is controlled by actually creating a difference in collective input to each of the separate rotors. So even though there is still obviously one collective, this difference in collective input is then controlled by the rudder pedals (best I know). This dance of difference in collective input to each of the two rotors is what gives an imbalance in torque between the rotors and thus your yaw control.
... but lose your engine and your are correct, no more torque input... thus no yaw control, something I had never realized! So maybe not so great for auto rotations after all 🤦♂️😂
There is some ability to maintain control however in a similar way if you lost your tail rotor in a conventional helicopter. More forward air speed will keep you straight by the air pushing the helicopter straight into the airflow. This is also why a lot of these helicopter have large vertical stabs (like this one having two) in the back, and even some of the large Russian ones I've seen with actual rudders to control this even more. I always thought these where just for extra yaw authority in the air, never realized they are also (and maybe its main purpose) for maintaining yaw control in autos.
Thanks for the insight! Hope you like the show!
-James
@@RelativeMotionCC - very interesting. I was thinking the vertical stabilizers at the back were mainly there to help stabilize things in cruise flight just like they do on a conventional helicopter. I'm not sure how effective they'd be at the bottom of an autorotation as you're going to be at pretty low airspeeds by the time you get to the ground so I'm not sure how effective they'd be but I'm sure they'd be better than nothing. I knew that the "rudder" pedals were inducing differential collective to control yaw. That much makes sense. I've been thinking about this and am wondering if this might be true. When you step on the rudder pedals, you're increasing collective on one rotor while decreasing it on the other. I imagine these are very small movements, maybe only fractions of a degree in most cases. Still, it seems to me that would change the drag profile between the two rotors and induce a yaw movement as a result. You're not going to be doing pirouettes this way but it may be enough to keep the nose pointed in the direction of travel over the ground at touchdown. At any rate, I've love to see a coaxial helicopter do an autorotation. What do you think?
@@RelativeMotionCC The section about “torque input “ is not correct…The 2 discs shafts get the same torque from the engine just turning opposite direction…there is no torque device in the transmission…both shafts gets the same rpm as well…I think.
The mixer mechanically links the pilot controls with which you manipulate the AOA of the blades and this changes the forces on the 2 rotor discs separately (rudder-yaw) and/or at the same time (collective-updown, stick-pitch&bank)
For autorotation rotor speed comes from “gliding”, the AOA and drag difference between the 2 discs to control yaw is still possible…
To maintain gliding you need speed…The last phase when cushioning for impact we exchange extra inertia of blades thus energie into more AOA/lift to decrease sink rate and speed…
With what device would you "unbalance the torque load" from the engine??? It is easy to say it but to build it... mechanically you get a heavy complex transmission part...remember coaxial helicopters (Kamov) were successfully developed and deployed in the 1960s... So unbalancing must come from changing blade aerodynamics forces...in my logic...
@@electricaviationchannelvid7863 - I understand what you mean about the "torque input" comment. Probably not the proper way to put it. The engine is applying torque to spin both rotor systems but that doesn't mean the both rotor systems are absorbing the same amount of torque. If one rotor is carrying more collective than the other, then the one with the higher load with have the greater torque reaction and that's the way the fuselage will yaw. How they do this mechanically between the "rudder" peddles and the individual rotor systems is still magic to me. I've never had the opportunity to examine one up close. That's kind of why coaxial helicopters fascinate me so much, and it's why I've posed the questions I have here. I'm just trying to understand. I'm thinking we're probably close to being on the same page with regards to changing blade aerodynamic forces to control all this.
How do you perform dynamic rotor balance? E.g. How do you determine where to add wts on one rotor system vs the other? I've balanced single rotor machines and find it easy if it is done with the ship in a hover so that ship vibrations are isolated from the ground and subsequent ground effects.
I’ve never balanced a coaxial myself either… but I would imagine it’s similar, you just might need a special kind of vib. machine to track each rotor independently… rotor balance sure is complex so I hope to do a video more someday going more into this. Great question though!
@@RelativeMotionCC I think that there must be some way to isolate the vibration caused by one rotor system from that caused by the other. I tried a test with a DynaVibe by putting an known out of balance wheel on my Bridgeport mill. The results were all over the place. It seems the vibration caused by my test wheel would cause sympathetic vibrations in the machine and the balance indications would be erroneous. We repeated this test with a motor and wheel mounted on my heavy test bench. Same results. However, when testing on a hovering helicopter it worked like a charm. Is there a way to hover a coaxial ship with just one rotor? That would isolate out of balance vibrations to just the one rotor at a time.????
I would think the DynoVibe, microvibe, or whatever vibe machine it is, it needs specific software or a program for co axial because it’s going to have a much different vibration pattern than a normal rotor… so if you don’t have a that proper program I don’t think it would work. And no unfortunately I can’t imagine you could ever run a co axial with only one rotor head
@@RelativeMotionCC would be good to see a dynamic balancing video for a coaxial. I built a coaxial and balanced the rotors statically span-wise and chord-wise. They ran very smooth and no adjustments were necessary other than tracking. If I had vibration issues I wouldn't know where to start.
I want to see auto-rotation of this helicopter in a power out situation.
absolutely want one of these. Hello from Panamá
Requesting intermeshing rotor system such as KMAX helicopter.
Talking about part 103 fuel capacity, i believe you can have multiple 5 gallon fuel tanks, but you need to land to switch them, they can't be switchable in the air, and that's legal.
Interesting point! Thanks
me gusta mucho esta bariante de helicóptero, que modelo es?
Can you change the rotors to 3 bladed
Awesome video
How do they perform in autogyro in an event of powerloss
Not the best, they lose tail rotor authority because it is a co-axial rotor
@@RelativeMotionCC co-axial rotors can still maintain yaw control while auto rotating because of the change in drag on the blades when the angle of attack changes such as when you press a yaw pedal.
yes please more
how much to buy ?
assuming that price is in dollars, I'm pretty sure you can get an R22 for less.
Remember the R22 is a certified machine with 2200 hrs max before very expensive refresh 70k but, your point is valid, I did have a Rotorway exec 47k cdn which flew well.
What license do you need to legally fly one of these ultralight helicopters? because I'm really interested.
You do not need a pilot license to fly ultralight vehicles. However, ultralight vehicles are subject to FAA's rules in 14 CFR 103.
wish this included the actual rotor noises
🔥🔥🔥🔥🔥🔥🔥🔥🔥
Make a drone like this and lift person in harness! This would be much shorter and it would fit even in a jeep or vagon kind of car
I saw a Japanese guy invent one smaller with just a small seat 4 legs & 2 blades
Linda maquina nossa quro yma d3ssa
I would much rather have the single place Helicycle & the 2 place Rotorway 162 Exec
👍👍👍
I want to own it, it's very powerful.
Linda maquina quro uma
What I do to save on training costs is tie a rope around me foot when I do test flights. The rope is tied to a tree so I'm good.
A Hirth two stroke??? It only Hirths for a little while..........
Mirocopter SCH-2A Small Coaxial Helicopter is for now the only FAR Part 103 compliant, weight < 115kg, and the smallest true coaxial helicopter in the world.
Unfortunately, Rotorschmiede VA115 is not FAR Part 103 compliant, weight > 115kg, and is not the smallest true coaxial helicopter in the world.
That price is clearly in the ripoff bracket. I bought a functional Rotorway for 47k cdn. Flew it for four years then sold it only b/c it was a bit tight to sit in.
According to it's website it's certified, that alone is going to balloon the price to something crazy. Then add in the engineering and the machining involved in a coaxial, I'm not at all surprised it's expensive.
👏👏💵💵💵🤔
Twin rotor is safer then mosquito
Mosquito XE / XEL is superior on the helicopter market --
Alot of Russian helicopters are coaxial
"Smallest coaxial heli in the world" You haven't seen the GEN H4 😉
No I hadn’t! Wow that’s tiny! 😁
@@RelativeMotionCC I don't know why they haven't started selling 🤨
@@RelativeMotionCC Wait till you see Franz Schöfmann's coaxial (I've seen two, one petrol, one electric) ! I want to build one with a single rotor and an innovative simple solution for the rotor torque.
Поздравляю, ещё одно приспособление укоротить вашу жизнь за хорошие деньги! Покупайте и не доживёте до пенсии.
$$$