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@@EIGYRO Not the same thing? Interesting. 👍

@@benshakespeare268 😉👍

@@getsideways7257 Is there a proper helicopter scheme ? Chinook tandem rotors, Kaman syncropters, kamov coaxial's. Are all these not proper helicopters ? I have nothing against the single rotor, tail rotor configuration and can see myself building one of those in the future too. The main reason for my choice was simplicity, coaxial's are not usually simple, far from it but mine is simple by comparison because it's not controlled with swash plates. It's controlled like a gyrocopter, just tilt the rotor where you want to go.

@@Ben-Dixey Oh... But I suppose you could make it even simpler going with a tilting single main rotor then? Or do you mean that only the top rotor gets tilted? I suppose that with a single rotor it's the body itself that will be getting tilted instead... Then again, too much risk with non-coplanar rotors even if there's quite a lot of separation. Also, you are risking your own life there implementing a DIY co-axial design, possibly endangering others a lot as well (since if anything goes wrong, it will resemble a grenade blast much more than with a single rotor). As for anything other than single rotors, yes, they all are not helicopters in my book. Controlling them is closer to operating a quadcopter (if one had swashplates) than a helicopter. It always puzzles me why people tend to fancy all those weird designs over pure single main rotor and a tail rotor. I suspect that's just because of the non-conventional looks most of the time.

@@getsideways7257 You could have a conventional single rotor, tail rotor with a tilting rotor instead of swash plates but there would be massive torque on the hinged rotor. Probably doable if the hinges are strong enough but the coaxial design cancels the torque. The downside to having a tail rotor is the loss of energy, all it's doing is counteracting the unwanted torque. Get rid of that and efficiency goes up, more power for lifting which is why the kaman and chinooks are used for heavy lifting. Not to mention the people that have been killed walking into tail rotors, very dangerous things if you ask me. As for my risking taking, live and let live I think, I don't tell people who base jump, deep sea dive, race motorbikes etc that I think they should stop. It's up to them, risking other people yes which is why I experiment alone away from people. However you can go and watch the TT motorbike race and stand extremely close to bikes going 150mph ?

@@Ben-Dixey I see. The more the reason to try and build a swash plate - they are marvelous pieces of engineering. But yes, they indeed are complex - and you would probably need things like dampeners too. Yes, the tail rotor barely contributes to the lift at all (even if tilted), but I believe your goal is not to slingload Humvees or evacuate groups of alpinists at specific density altitudes. You are doing this to have fun, right? What could be more fun than learning to subdue a small classic design helicopter? Although I admit the risk of a pilot error is noticeably higher that way, but so is the reward. Also, you don't seem to be unprepared for that, not to mention using a few simulations would most likely help you prepare even more. I'm not telling to stop taking the risk. I just believe the coaxial design is inherently more dangerous mechanically - including the possibility of much more fragments flying in all kinds of directions if something really bad happens. If you say there is very little probability anyone gets hit in that case considering the location of the tests, I guess that's ok then. I'm not entirely against risks, but I believe calculated risks are much preferred to doing something like IoM TT. That said, I can fully understand the riders taking part in that race. Personally, I'd rather come up with a sim good enough to be a replacement for that... Ah, and speaking of Chinooks... There is CH-53 and if that's not enough there is also Mi-26. Should be plenty stable even while of the conventional design.

@@getsideways7257 Yes the main reason for this project and the flying boat project is primarily to have fun. I wanted to learn all about helicopters and a project like this makes you do the research. I also wanted to use the engineering equipment that I bought and make things I have never made before. Lastly I wanted to learn to hover a helicopter, a side benefit if I can perfect the machine is a hovering toy that I can enjoy for years to come. I had no idea how much there was to learn, not just about helicopters but everything related, materials, drive systems, engines, physics, aerodynamics even making videos on CZcams! . That knowledge can of course be used in future projects. The heavy lift helicopters you mentioned are of course incredible machines and they had their reasons for using the standard configuration. I'd like to know what the reasons were but we can guess. Simulators are great tools, I used one to learn some rc flying. Cameron Carter on YT used one for teaching himself to fly his homemade helicopter. He used the actual machine as part of the sim, attaching the electrics etc to the mechanics. He said he was able to hover pretty quickly from the sim practise. I considered doing the same but mine isn't the usual design and thought it might not be realistic enough. After flying an R22 the cyclic is similar, similar type corrections so I think it would have helped. The collective vs throttle on altitude control is very different as are the yaw vs anti torque pedals. Extended poles work well for hovering Practise, just like the models.

I think it's interesting too. Determining the phase lag is no doubt difficult, I did see a quote online saying that the helicopter manufactures do it by trial and error. Not sure if that's true but it wouldn't surprise me. Does a coaxial cancel the phenomena ? Two single rotors acting Independently isn't it ? 🙂 I suspect if you had a teetering top rotor and an offset hinge bottom rotor but kept the same phase lag on both the rotors they would want to go in different directions?

@@Ben-Dixey If the two rotors have the same angle of phase lag, they will try to tilt at different angles, but the main mast will tilt in the combined direction, so I think the effect of phase lag will be eliminated. I'm sorry for my poor English, as I'm using Google Translate to help me communicate.

@@mitubachiflight The English translation is good. 👍 I think if for example the top and bottom rotors are hinged in the middle, like mine, (teetering) then phase lag will be 90 degrees for both. The rotors spin in opposite directions so both rotors will tilt in the same direction. If both rotors have offset hinges, like Robinson and the tri hinge rotor head phase lag for both rotors would be for example 72 degrees. Both rotors again tilt in the same direction. If there was some reason why one rotor titled in a different direction from the other then yes there would be a conflict between the rotors and the result would be somewhere in the middle. Do you agree ?

@@Ben-Dixey I agree with most of it, but I don't understand how the phase lag appears in the same place even though the rotors are rotating in the opposite direction. Maybe I'm not understanding it well enough? I'll think about it a bit more.

@@mitubachiflight Ah I see, yes we are trying to understand the phasing of coaxial swash plates. Definitely very confusing. My coaxial does it automatically, just tilt the mast and the pitch/angle of attack of the blades change 90 degrees before and in the right direction to move both rotors the same way. Just need to copy that for coaxial swash plates but I can't say I've got my head around what needs to happen when the phase lag is 72 degrees. I would imagine it's the same only everything is offset 18 degrees but I could be wrong.

Thanks very much for the comment Martin, I always appreciate your input, you're a clever guy.

Stick to your toys buddy, much more your thing - think you'll find this channel is for grown ups...

Training skids, they work really well for teaching yourself to hover a helicopter. 🙂

Looking at the comments below regarding the Robinson helicopters, looking at a side picture of the head, it appears to have an advance angle of 72 degrees (the number quoted below), which means that the swash plate is offset 18 degrees to the right (ie when you want to tilt the disk forward, the swash plate is tilted forward and slightly right (I might have the left right confused). The rotor turns anti clockwise when viewed from above. This is roughly what I remember from when I instructed on them about 20 years ago. My 3c (2c + inflation 🙂)

@@johnreynolds1184 Hi and thanks for the message. It all comes down to the actual phase lag of the helicopters mentioned. You are saying that the Robinson has a phase lag of 90 degrees made up of 18 and 72 in the swash plate and pitch link horns. From my research Robinson helicopters don't have a phase lag of 90 degrees it's 72 but that's only my research and I would like to try and measure it in real life. The Information you linked suggests all helicopters have a phase lag of 90 degrees. I do have a quote from Frank Robinson talking about the 72 degree phase lag but it doesn't mention what the advance angle is.

I think that could be the lesson I've learnt from posting the video, I think I was wrong to suggest they are too different things. At least that's what I'm thinking at the moment until someone suggests otherwise.

@@Ben-Dixey you did pretty good overall covering factors involved. It's a topic most people don't understand very well. I'm not an expert in it either. But I am a CFII Helicopter and Aerospace/Mechanical Engineer. I've never personally designed a rotor system though. I'm just looking at things logically from first principles, and from everything I have read on about it over the past 15yrs, both in engineering texts and pilot handbooks. I take what each book says, then test it against the laws of physics to see if each explanation is valid or not. then look for common factors in all the explanations that withstand initial scrutiny, and again compare to the laws of physics. Rinse and repeat with every new piece of information I find/encounter, until I've refined the explanation and my understanding down to very basic principles that nobody is able to refute. If my arrived at understanding is valid, then it will hold up to any/all criticism. If someone finds a valid hole/flaw in my explanation, then I update and revise my explanation accordingly in response to that new information.

😆👍

Thank you 👍 the car is a lot of fun, they don't allow kit cars in China ? I did a video about the hiller fly bar in this video. czcams.com/video/uogPHtWN9Lg/video.htmlsi=h7nPkkl5-uws8VBX What I believe it does is reduce the sensitivity of the controls and also stabilises the rotor. A wind gust will have less effect on the rotor with a flybar I believe. I think rotor heads like Robinson have solved the issues with wind gusts by having delta 3 designed into the rotor heads. Did you design any delta 3 into your rotor head on the two place machine ?

@@Ben-Dixey Thank you for your video. Only the tail rotor have the delta 3 in my helicopter. The main rotor is a seesaw.

There are loads more videos after this one.

Hi, yes the rotors have teeter hinges, The vertical distance of the rotors are set at 10% rotor diameter. From research this was thought to be the most efficient spacing.

What is the fixed pitch angle set at?

@@bradsamers3014 currently 6.5 degrees bottom rotor, 5.5 degrees top rotor. I suspect more lift would be generated with more pitch but more torque would be needed and that means changing the gearing.

The rotor dynamics is more like mass-spring-damper system than gyroscopic .

I find that this book is the best one to clean all misconceptions about helicopter aerodynamics : www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=aerocastle.files.wordpress.com/2012/04/35717799-aerodynamics-of-the-helicopter.pdf&ved=2ahUKEwiH3_DGt_aGAxW2UKQEHZQ9BnYQFnoECA8QAQ&usg=AOvVaw3lsXFRQAwGqqsoCqvGDDJl

I know naught people who say Zero.

plenty of people say naught. It's a valid word, and it's valid to use it. For example, Dreadnought = fear not Free Speech. Don't moan about people speaking in their accents, dialects, languages, etc.

@@SoloRenegade Plenty of people where? Other than some twisted suburb in the UK? The entire world that I've seen says ZERO! Including the people who invented zero. And since you're moaning about my comment, its FREE SPEECH!

Oh, the unhappy crowd doesn't like being told how out of date they are with their language. LOL. I did a little research before commenting and you're right, Zero actually is the correct word to use these days and you're right again that the entire world uses the word Zero.

@@jrpo6379 cite the place that enforces speech, and tells people which words are approved and which are disapproved. I'll wait.

Thank you, after our correspondence it inspired me to go ahead and make the video but its dam complicated to get your head around. I read some information online that said even Sikorsky use the trial and error method of finding the correct phasing.

@@Ben-Dixey Thanks heaps!

Good question, it would depend I guess what they wanted to achieve. As a tool for experimentation the design is fine but I think we both know that the cyclic feathering for control is the winner. I would like more time with the machine to really learn more about it, I hope I get that opportunity and pass on the information gathered. The Nolan's did a lot with this design so it must be capable of more than I've demonstrated.

I thought you were rating the video 7 out of 10. 😆 thanks, the car is a lot of fun.

thank you 😊

😆👍

Hi, any kind of wind on a rotor changes the alignment of the disc to the shaft. I think without exterior influences they will perfectly align, Arthur Young demonstrated this in a video. An autogyro tilts the rotor forward for example and the pitch change of the blades happens 90 degrees out of phase. It's exactly the same as cyclic control and mine is the same too. Pitch change is a confusing term in this respect, I think it should be called angle of attack change because as we know autogyros have fixed pitch rotors. The bottom line is when the rotor is tilted the aerodynamics control the rotor through cyclic changes in angle of attack.

@@Ben-Dixey Ah, I understand now: It is not changing the angle of the disk by force, but say pushing on the joystick to raise the front of the disk is ACTUALLY (in a CCW from above rotation) is really increasing the AOA at the RH position which applies the lifting force 90 degrees at the front: I FINALLY understand gyroplane rotor control! Thank you. Keep the great vids coming 🙂

@@BrilliantDesignOnline That's it 👍

Thanks for the comment, would you agree Robinson rotors have a phase lag of 72 degrees?

@@Ben-Dixey Maybe? I think there's some distinction that needs to be made. I believe the designed phase angle for all helicopters is 90 degrees. There is a phase angle shift that is the cause of blade loading, aerodynamics, and resonance which I believe you're referencing here. For example, on the pitch horn leads/trails the blade by 45 degrees and swashplate displacement is 45 degrees on 4 bladed Bell helicopters (90 total). The Lynx has a similar offset to Robinsons, 15 degrees ahead of the lateral axis. Because of its stiffness and the phase angle shift, the disc would move in uncommanded directions. The solution for the former was a black box sensing system that detected uncommanded movements and made servo inputs to move the blade into the commanded position. Robinsons do not need this because the Lynx has a 15 degree offset and a 90 degree phase angle, whereas the Robinsons have a 18 degree offset and a 72 degree phase angle. So no correction with servos is needed. So yes. The phase lag exists, but there is a designed offset that makes it still add up to the 90 and some helicopters have advanced systems to assist when it doesn't. So both things are true, phase lag exists and gyroscope precession functions as it should in most cases. I gotta do more reading though, I'm typing as I'm learning here so not fully vetting all information.

@@Maverickib Ok, I'll have a think about this. I've read about blade loading changing the phase lag or offset. Blade loading would effect the frequency too wouldn't it ?

@@Ben-Dixey I'll also have to think on that more. Initial thought is rotor systems are designed to cone under load via hinges or blade flexing. That coning may be engineered to also adjust frequencies so the phase lag doesn't change under varying loads.

So why don't you explain your understanding of it. Without explaining, your comment can be perceived as misinformation.

If I'm wrong I'm more than happy to delete or edit the video. Like you, I don't like misinformation. Please explain why this is misinformation.

@@Ben-Dixey I won't write a dissertation in comments. You have several concepts confuzzled here. Destin's explanation isn't wrong nor is Veritasium's. Have a look at any manufactured helicopter with the collective at full pitch and the cyclic full forward. Rotate the MR and take note of where you see max pitch. It'll be at 90 degrees (L or R depending on the rotation direction). The swashplate does not impart twisting forces on the MR blades so quickly that it would induce any noticeable lag. Noob pilots that move the cyclic too quickly for the MR system to react incur PIO. That's why you're taught not to abruptly move the cyclic. The control tube mixing box isn't at something ridiculous like 78 degrees, it's at 90. I could go on and on here but here's another short youtube that might help. czcams.com/video/n5bKzBZ7XuM/video.html

@@chopper3lw Ok, I think I was wrong to say that Destin was wrong but I do think my explanation to phase lag could still be right. We could be talking about the same thing but explained in different ways ? I had seen the video you linked on gyroscopic precession and don't disagree with it.

@@Ben-Dixey He doesn't know what phase lag is.

Thank you 👍 CAD designers are very useful people, love what CAD can do.

​@@Ben-Dixey Thank You Ben :) ....I think about design in Inventor small Heli.. like Yours ... for traveling the World :) ...Cad tool will be useful but, knowledge end experience is important too ....CAD is only tool like hammer :)

Hi Ben, your videos are very informative.

Interesting comment, I'll give that some thought 👍 A quick glance at your channel, did you build that machine that goes into the wind using prop driven wheels ?

@@Ben-Dixey I did. It was initially designed and configured to go directly downwind faster than the wind. In this configuration the wheels drive the propeller. When I reconfigured it to go directly into the wind faster than the wind, I had to replace the propeller with a turbine, and reverse the drive so the turbine would drive the wheels.

@@Rick_Cavallaro I knew I had that prop driving wheels the wrong way around. Ha! Great to have contact with you I watched the video from that science guy all about it. Sounds like I have some catching up to do on your channel.

@@Ben-Dixey I have sort of a non-channel. I typically just post things to share with friends. But a few days ago I posted a new brain teaser that I really like. I'll post the answer in the next few days. You should check it out and weigh in with your thoughts.

@@Rick_Cavallarosounds interesting, I'll have a look. 👍

Hi, the rotors are gyroscopes yes but aerodynamics control the rotor. My blades change the angle of attack as they rotate just like a helicopter with a swash plate. The aerodynamics act like servo assisted steering for a car and that moves the discs even though they don't want to move being gyroscopes.

@@Ben-Dixey well at the end of all this Ben is this the reason why they build helicopters with swash plates and cyclic pitch change, and not the configuration that you've have ?

@@cloudusterable you need blades to feather to autorotate, if you need blades to feather you might as well control the machine with cyclic feathering. With a coaxial as you know double swash plates can get complicated particularly with differential collective. I don't think the tilting mast will replace anything outside of a home built helicopter but gyro copters certainly make use of them.

I have read that a ridged rotor has virtually no phase lag but I've also read the BO105 has 75-80 degrees of rotor phase lag which is a ridged rotor system. A rotor system with no phase lag doesn't make any sense to me. Even if the blades are ridged it would still take time for the blade to flex up to maximum displacement. A blade that is rigidly mounted still has a frequency at which it oscillates doesn't it ?

@@Ben-Dixey Безусловно любая упругая балка, закрепленная с одной стороны, имеет свою резонансную частоту. А по поводу BO-105, если рассматривать максимальный угол установки лопасти для движения ЛА вперед, плоскость качания шайбы автомата перекоса необходимо повернуть с опережением на угол ~75 градусов из за некоторого смещения точки приложения сил к поводку лопасти, на который действует вертикальная тяга. Угол установки лопастей над хвостовой балкой (0 азимут) будет иметь пик как раз при опережении шайбы 75-80 градусов. В шарнирной схеме все сложнее и имеет место то, о чем вы упоминули

Thank you 😊

👍

The axis Angle ? I'm not sure what this means. Blade pitch angle ?

Thank you 😊

@@Ben-Dixey.....:) ....knowledge is power ....

Hi, the electric fan I'm using is drawing 17 amps, gauges and water pump is 1am. I think I need to go to a belt driven fan. When I do that modification then it would make sense to sort the Johnson stator and remove the external alternator. Think a replacement stator is rated for about 5 amps. I didn't know that about the later single phase outboard charge systems being more efficient. 👍

17 amps for an electric fan is a lot. I think you can do better. I'd expect an efficient brushless 'continuous duty' fan to have a start current around 20~30 amp [dependent on cable area] and run current near 10 amp. I'd select a scimitar shaped fan blade. They are more efficient so draw less current to push or suck more air. If possible look for a brushless design often much more efficient like 80% rather than 30 to 50% for a brushed design. How good and close is the seal onto the radiator? The better the seal the more heat gets transferred to the atmosphere with less air short circuiting around the edge of the fan and not through the radiator. Does the fan have a good end plate around the tips of the fan blades again making a big improvement on efficiency. As a bonus this air resistance or more work being done also means slower fan speed and often less current. How near the top of the radiator where the coolant is the hottest is the fan mounted? Much better to move the hottest air. How large is the fan? This as It's a lot cheaper and more efficient to move a lot of air a little than a little a lot.

Later charging systems are superior due to the more efficient regulator regulator rather than a larger winding inside the engine.

@@donaldpayne1376 Thanks for the info. The fan I chose is Spal va08-ap70/ll-23ma It's brushed I believe, I went for the highest CFM and largest diameter I could fit to the radiator. It's a pull type fan straight bladed and 14" diameter. The fan is as close to the radiator as possible without risk of touching it and shrouded. The shroud is welded to the radiator so it's a perfect seal. Data shows it can pull 1600 cfm at 17amps. I haven't looked at the brushless ones yet but will have a look.

@@Ben-Dixey Good job on the shroud seal. Is the fan on the correct side of the radiator so its encouraging heat to rise? Might be a contradiction if it's in the rotor downward area. I'd look at scimitar blades & continuos duty as well as brushless. I'd also stay away from a reversable blade as its a compromise with sub optimal performance both ways. I wonder if a larger radiator would help. Keep up the great work, it's fun watching your progress.

Sounds good to me. If the reversing gearbox was also a slight reduction drive then the extra lift generated would easily compensate for the gearbox weight. The belts would be under slightly more strain but not much I don't think. Easily calculated and checked.

I'm not sure why the belt[s] between the engine and gearbox input end would be doing more work with a gearbox rather than large & small pulleys. Maybe you are referring to gearbox losses. The gearbox could do the majority of the reduction allowing adequate pulley diameter [ pulley wrap ] of both the engine and gearbox input to reduce excess flex maintaining good efficiency. The gearbox could also carry the bottom of the swash plate stack. My '82 microlight uses 4 A section belts between a 30hp 2 stroke and propeller providing a 2 :1 reduction. Some have a 40hp using the same 4 belt 2 :1 reduction. Maybe talk to your local auto transmission shop for a look a planetary reduction stacks.

Can't wait to meet you Tyger, You're a real character watching your videos and always make me laugh. We'll have a fun day I reckon.

I just tried it out of interest, I measured a piece of steel with a mic, then marked both sides with the sharpie. No measurable change in dimension. New cars for example have a paint thickness of between 0.08mm- 0.120mm. That's the primer and top coat, a sharpie being 0.025mm I can't seen happening in one application, etch primer via gun maybe, but then it has to stay on during the press fit which is also unlikely in my opinion. Sorry to disagree but it doesn't seem right to me.

Relying on parts to never fail within normal circumstances.

It's not unfortunately, the rivets are staggered on each side as to not interfere with each other. I think new blades are the solution, but I did temporarily solve the issue using helicopter tape which seems to have stood the test so far.

👍Two belts on each drive would be safe for sure but the penalty would be the cost and extra weight in pulleys and framework etc. Every decision is a balance of cost, weight and safety. If a single belt is guaranteed to last say 100hrs I think that would be acceptable in terms of cost to replace and safety.

Hi and thanks. Deflection rollers? Is that where the belts are deflected around the opposite side of the large driven pulley ?

Good point. Think chains are well and truly out. Shame, as it could have increased the lift significantly with a lower ratio.

@@Ben-Dixey I think chains might be workable, will be heavy though.. Cush drives in the rotor head will be a complete rework, probably you could retask some motorcycle engine clutch basket, or just use the whole motorcycle engine. Thats a lot of reworking though...

I had forgotten about the efficiency, difference good point. 👍 Think the belts are 95-98% efficient. Chains will get less efficient with heat and at high speed too.

@@Ben-Dixey They also don't wear out the belt pulleys like chain does to sprockets. It's the main reason a lot of modern cars have timing belts instead of chains, not all but most. Chain has a bad habit of stretching too, needing constant adjustment and lubrication. In a machine like yours where efficiency is paramount, belt drive is the way to go imho.

I like your rc models 👍😊

Perhaps so but the comments are only there to start the research process. It wouldn't be wise to blindly follow a comment without researching it.

Hey, I have to disappoint you on this I'm afraid because the hovering is old footage from before the driveshaft broke. I just used the footage to accompany the narration, there will be new video of hovering but it will take some months to get it back operational again. Apologies for misleading you.

@@Ben-Dixey oh no disappointment, I understand this is continue process of the improvement... believe you very much . Great Ben