Homemade coaxial Helicopter walk around and explanation
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- čas přidán 16. 03. 2021
- A bit of information on my chosen design.
I still have to finish the blade straps, feathering pitch links, teeter stops, teeter bushes and shims and a few other things before any rotor testing can commence.
The engine will be run with a 12v pump supplying cold water for now, I have made a prevision for a belt drive fan off of the flywheel when a radiator is finally mounted for onboard cooling. Also I won't be making any Yaw controls until the blades have been run up and have proven lift capability.
Getting the rotors up to flight Rpm will be the first challenge, I will obviously balance the blades but I think it would be some miracle if they ran smooth straight away.
My day job is welding on classic cars, if anybody is interested my new channel is:-
/ @bensclassicbodywork - Hudba
So much work. Impressive. And smart solutions. More impressive.
Fantastic! Great to see! 👍👌
thank you my love
Top marks, well done
Thank you 👍
Thank so much
Super excellent sir👍
Nice job!
Bloody incredible!
thanks 👍
Excellent work hope it works out for you.I'm also building one so I can appreciate the level of difficulty.
Thank you. How is your project progressing ? Your first attempt looked great until the mishap, what did the cyclic feel like at 600 rpm? cheers
Learning how contra rotation mechanism gears work from your design, i become understand. Thanks. GBU
The co-axial reverse system could be done with a chain/sprocket system which at first glance might be lighter and simpler but I'm sure you have done your homework and opted for the belt system for good reasons.
Very well done !!
Thanks, yes I did look into chains, I think using a 430 chain was the recommended size but I seem to remember reading the recommended speed of the chain would have been exceeded. Running the chains in an oil bath might have been a solution but then the belt idea was looking a better option. Chains might have been ok run for smaller time periods without a bath I wasn't sure so I went with belts. It certainly would have been much more compact and probably lighter, not to mention a lot cheaper.
@@Ben-Dixey I can imagine that the belt system wasn't cheap at all but it's a neat concept and probably far less noisy than chains/sprockets , almost maintenance free.
You did a wonderful job so far sir , congratulations , keep up the goodwork.
leemnav thank you for your kind comments, much appreciated. Did I read that you are building or have built something similar?
@@Ben-Dixey Yes , " I messed around a bit " the past 45 years but not nearly as good or succesful as you have done.
One thing good that came out of that is that I learned how difficult it is and therefore highly respect the work of others that even dare to build their own helicopter.
I had the good fortune some years ago to meet and see Mr. Franz Schofmann flying his trypod co-axial helicopter and that was and is still by far the most inovating "helicopter" I've ever seen . ( I know that in mr. Schofmann's case the term "helicopter" is used in the broadest sence of the word )
Your machine and that of mr. jpkrucker come very close regarding dedication and thinking outside of the box. !!
I keep following your progress and the best of luck to both of you , you guys get there , no doubt about that.
leemnav inspiring words my friend, I agree that the Schoffmann helo was something I didn't think was possible and totally admire his achievement. He seemed to set off a bunch of people on their own quest to build something similar. I think win or fail the process forces you to better understand a lot of engineering principles, there is just so much engineering to understand in a helicopter and mistakes are unfortunately expensive in this game. I wish jpkrucker the best of luck, it was a substantial achievement to get to 600rpm with his rotors in my eyes. Respect.
This appears to be a crazy invention that is a machine that has no purpose as it lacks a collective. It's like crazy looking work of art. If it makes the builder feel better great.
If he thinks its actually going to go a test flight then its really a sign of madness.
Well it depends on your goals a lot of the fun in a helicopter is hovering and learning to hover. A helicopter with collective is no safer than one without in the hover, you need a few hundred feet to transition from powered flight to autorotation. A fun field vehicle is my goal and a learning experience to perhaps progress to something that could get an airworthiness certificate. I think madness would be flying this machine at height, not something I would attempt or advocate.
@@Ben-Dixey You sir will be spinning in that thing instead of hovering. The downwash from the top rotor gives the blades on the bottom rotor a smaller angle of attack. Hence both rotors will experience different torque.
Aviator168 thanks for the comment, yes I expect i will have to set the bottom rotor to more pitch to equalise the torque. The pitch cannot be altered in the air but can be set on the ground. Have a look at the gen4, Nolan helicopter and air scooter 2 all have fixed pitch coaxial rotors.
Certainly high end engineering quality Ben ........the flexible drive coming of the flywheel did you make the housing for that, also Is there much vibration from the engine being a big 180 degree twin ?
Thank you Peter. The flexible drive coupling is one I bought from KMproducts they make and sell hovercraft parts, then I made the clutch drum to suit the drive coupling. I had to add a supporting shaft which bolts to the coupling on the other side from the drum to make sure the bottom cv joint was not able to flex out of line with the engine but could allow some flexing in the rotational axis. There are bearings inside the clutch basket to allow the driveshaft to stop while the engine is running and when the clutch is engaged it's all locked together anyway. Yes the engine has a lot of uneven running and vibration until it gets to about 4000rpm after that it smooths out beautifully. cheers
Nice project a lot of thought there ,,, curious I am into airboats and hovercrafts . I noticed your 8mm pitch sprockets . Were they specially made for you or is there a source for them off the self ???? Thanks ED
Hi Ed, I had Kmproducts make the toothed pulley blanks, then I machined the spokes and hubs etc. They would have done this for me too if I had paid extra.
Love the fiber lock nuts in a high vibration area, none captive (Castle nut),Im thinking my Ex-wife would be a great candidate for flying this fine aero machine. Oh yea the wood/micards block on the main rotor is a fine touch.
Captive nuts aren't necessary on a proof of concept prototype and if you listened to the video I said wood won't be used as a blade strap material, 7075t6 is what I used.
Wow you have been a very busy boy.
It's been a mission 👍
My Rotorway had an update to the chain drive to a belt like you have. It sounded a good replace, lighter etc. In reality the belts wore out to fast so the chain was better.
Interesting, I suppose if you compare an automotive engine synchronous cambelt to a cam chain, the chain will far outlast the belt. I love the Rotorway Helicopters and enjoy watching their maintenance videos.
@@Ben-Dixeywould the chains work like the belt in engine rotation reversal?
@@TO-ll4js I think it would work ok but extra heat generated could cause a problem. I did videos on the chain drive option recently, chordal effect on a chain drive I think would be a problem. I'm sticking with belts for the time being.
Great work and impressed with the belt drive system for the counter rotation. As you have fixed pitch blades, and the rotors are fairly small in diameter, the inertia would not be very high. Are you considering adding mass balance weight at the tips or have an alternative avenue towards a safe outcome due to engine failure. I ask from having this occurring twice in my flying years. One was so close I nearly gave flying away and the second I was prepared for. In your case I am concerned that above a low height there is no safety reserve without collective.
Thank you for your comment 👍 The plan is to go no higher than a few feet above the ground, I completely agree it would not be safe at any higher altitude, the rotor rpm will decay immediately. Low inertia blades is what I think it requires for throttle response to work well in controlling altitude. Collective pitch would be the way forward for flying higher or dual engines would be an option.
i guess it's kinda randomly asking but do anybody know a good place to watch new series online ?
@@Ben-Dixey
As a aircraft maintenance engineer and a RC helicopter pilot for 30 years I know all to well what happens when fixed pitch heli suffers a engine failure, unless you are a few feet above the ground they tend to make a nice smoking hole.
But with my collective pitch helis my autorotation landings are always better than my powered landings. 😀🇦🇺
John O I agree with you, collective pitch would be the way to advance to higher altitudes than a few feet. Not sure how much help collective is on full scale at say 5feet high as I believe it takes a few hundred feet to transition from powered flight to autorotation. This I think was the argument for the airscooter 2 but it disappeared. My guess is the temptation to take a machine like this higher when it is not safe to do so would be very great, so making and selling this type of machine to the general public would be morally wrong with only a single engine.
I believe the Nolan had dual engines…More complex, but better safety factor. A lot of folks rooting for you & this highly intelligent design!…hoping for, at least, detailed plans to become available at some point.
I look forward to 1st test engine run up
Thank you!
@@Ben-Dixey where are you located. No specifics
Bruce Young I'm in North Devon
@@Ben-Dixey England?
@@Ben-Dixey oh. Never mind. Don’t have to answer. Wink wink nod nod. Lol
Great build, thanks for sharing (an electric version would be nice in future ;))
Yes, an electric version would be much better, I like engines but don't like all the vibrations and uneven running. 👍
@@Ben-Dixey Maybee you dont know this project www.hfpower.co.nz/Oskacopter.pdf he has also an youtube channel. Here I have seen an electric helicopter the the first time ;)
ABS. Thank you, I have seen the CZcams videos but haven't seen the article you attached. Will have a read, cheers
Ok mantap bang 👍👍👍
Pretty slick! I assume you're not done boxing in / triangulating the gear box frame.
Thank you. The drive frame structure is something I'm not happy with. The aluminium angle isn't strong in torsion and that's the load it will be resisting. I either continue with more bracing or replace the angle with box section. Good comment !
Super
Woww nice👍
Thank you !
I noticed several Nylock Nuts attached to parts on the main drive shaft and rotor head, would these not be better secured with fasteners designed for lock wire retention?
Hi, yes you are correct, the most important bolts I have been wire locked which I believe is sufficient for prototype testing. If you were building a helicopter for flying hundreds of feet up and for long service periods all the bolts would be wire locked. There are some nylock nuts which if the prototype is going to be tested for longer periods I would swap to wire locked.
Good evening sir. Have you completed the construction of main rotor blade?
Is there a limiter for forward and reverse? as i have seen in the video when you were tasting the lever of forward reverse then the bearing inside the cv joint was half visible outside i mean that the length of the cv joint hub which is there will not have to be increased
Yes I have completed all the rotor blades and have tested them to full rpm. m.czcams.com/video/xb4N3hOlrmM/video.html
There are two plunging cv joints each will allow travel of 50mm giving a total of 100mm. This will allow the mast to tilt forward and backwards of 5degrees in each direction. I hope this will be enough but I'm not sure at this point. I am expecting the movements for a controlled hover will be very small. But good question and observation 👍
Considered any dampening on those axis? Such as those found on motorcycles for the steering head?
Only by video comments, in fact some helicopters have cyclic friction which acts similar to a damper. Might help, might hinder, I'm not sure
👏👏👍🚁
How are the pitches of blades changed? It also looks like the rotors will be rotating at the same RPM, and the asymmeteric torque problem still be there.
Hi, The pitch is fixed when flying but can be altered on the ground, I can set each blade individually to balance the torque and tracking. Each blade can feather on its axis and is held by a threaded rose joint.
How do you change the collective pitch of the rotor blades??? Didnt see any type of pitch change linksages anywhere. Or is the rotor system at a some type of fixed pitch angle???
That's correct the pitch is fixed and lift is controlled by rotor speed. It's done for simplicity but the drawbacks are delayed response time and you can't autorotate.
@@Ben-Dixey Okie dokie. . . .thankya for responding! I was also wondering about any autorotation or not! I sure hope ya can get all the bugs worked out & be a flyable ready stage👍🏼👍🏼👍🏼
Great build. Where did you get the double tooth belts form? Currently building one man helicopter. Using a geared contra rotating gear box.
I downloaded gates drive design software, just don't tell them your using it on a helicopter or they will refuse to help. How far have you got with your project ? Sounds interesting
@@Ben-Dixey I copied this deign (czcams.com/video/OM7HHB51WX8/video.html&ab_channel=AviationExplorer) I have the gearbox built , three legged frame. I'm going to use a Harley-Davidson engine laying on it's side.
The Franz schoefman helicopter was a great piece of engineering and was one of the videos that inspired me too. What overall weight are you predicting ? Hp?
You need lock wire on those critical nuts!!!!
Yes. Happy to add lockwired nuts as testing progresses. Wanted to see if the project is going to be successful first. 👍
I know nothing about anything shown in the entire video: that being said... :D Would it not be better to have a second shaft next to the main drive-shaft connected by sprockets to reverse the rotation and allow you to run the belts the same way on both pulleys? Do the super tight radiuses on the belts not cause wear and inefficiency?
Thanks
It would certainly be better for belt wear and perhaps efficiency. But it would add weight to an unbalanced problem on the hinged head. This would mean more weight on the front to counter it. My reversing belt wear is of some concern, perhaps not for a prototype but it would need to be looked at otherwise. Good comment 👍
did you build or buy those cogged drive pulleys? if bought where from? Also would love to know more about the sprag clutch, where did you find that and what are other applications the manufacturer markets it for?? very very cool project
Thanks, the large diameter pulleys where supplied to me as toothed blanks by KMProducts they make hover craft parts I then machined out the hubs and spokes. They are HTD profile but the belt is GT2, the small ones I made copying the GT2 profile onto a fly cutter. I would have made the large diameter pulleys myself but didn't have a dividing head at the time. It doesn't actually have a sprag clutch at the moment because I removed it to fit a smaller drive pulley but when I did i used one way bearings, these were keyed both sides and I used 4 of them to make sure they could handle the torque.
@@Ben-Dixey very cool. thank you for the insight. absolutely fantastic project you have going here.
whats machine used
Can the rpm be controlled separately for both rotors?
Hi, it would be nice to be able to control the rotor rpm's separately but this isn't possible in this case. It has been done before using a differential drive and braking one rotor for yaw control.
Glad I took a second look at this as I had mis-remembered some things, for some reason I thought that the engine was attached directly to the gimble and moved with the cyclic ... glad that's clarified !! :)
But now that I have had a second look at this video I'm wondering about the cyclic range limits and also might it be better to re-arrange the power to operate more like a traditional collective lever so that muscle memory habits from developed from your lessons would relate directly to the operation of this helicopter, I think that's something that might throw me a little.
One other thought also occurs to me is would there be any value to putting a gear reduction between the engine and the flex drive as this might reduce the torque spikes and it would also allow you to increase the pinions driving the belt thus increasing the somewhat sharp radius and reduce the bending angle, belt life and all that. I know, more cost, weight and complexity:)
Hi mate. Yes I have changed the throttle to the conventional pull up to go up now. Much better having it operate the standard way.
It's an option to add another reduction but it's something I wanted to avoid. I wanted a single reduction for reasons of weight and efficiency. Keep things as simple as possible but I know I'm pushing the limits on the belts in my current configuration. I will have a think about it though. I would be increasing torque but reducing speed on the drive shaft which is something to consider.
@@Ben-Dixey ah such is the compromise of design :) ... the extra torque would be welcome for the upcoming increase in blade pitch angles but the lower head speed would not, back to the debate about blade length again and finding that sweet spot of a compromise between these three variables.
Having the controls move in the direction you want the heli to move in really helps with the old snake brain instinctive reflex thingy ma bobs. :D :D :D
The Va115 uses a tip speed of 492 ft/sec for the same rotor diameter. Any thoughts on this ? My blade speed is 576ft/sec. They are using a 50hp engine though but a max take off weight of 260kg.
@@Ben-Dixey these helis with just latters and numbers for names are so unmemorable to me, why can't they call them the waspette, dragonflyer or Hornet ? :)
Anyhow, there are a couple of other variables to play with here, aerofoil section and thickness and chord length. If they're running a lower head speed they must be using a thicker or longer aerofoil .. or both ...
Although, they could also be using a none symmetrical section, and maybe even built a set of composite blades which also have taper and twist built in too.
Are you able to talk them ?
@@Ben-Dixey What's your current take off weight at the moment ?
i saw an outboard motor engine on it How are you going to Cool it, Outboards are water cooled
For testing I've just got a reservoir and 12v pump but if I can get it to fly I will add a radiator and belt driven fan. I'm expecting quite a bit of modification and trialing to get a system that works. Cameron Carter managed it with his helicopter and rotorway used outboards in the beginning so I know it's possible. Certainly would be easier with an air cooled engine but the price isn't cheap for such an engine.
What is the length of the rotor and pitch angle?
The rotor diameter is 4.3m and the pitch is 6.5 degrees on the bottom rotor, 5.5 degrees on the top rotor.
How heavy it is (approximation in kg) and what is the power output?
Hi. The weight for the first run up will be around the 110kg mark, if it has any potential to work I will continue to finish the cooling system and yaw controls etc and the expected empty weight will be 130kg. The maximum take off weight I'm expecting to be 300kg. The engine produces 60hp and 55lb/ft if torque.
I wonder is it safe to use cars back axial Spider Gears instead of pulleys in order to make coaxial copter ?
It would be very safe to use those gears as they are designed for much higher torque than would be put through a small helicopter but are heavy.
@@Ben-Dixey First thank you for your replies , Heavier ?! , I mean just the spider gears without pinion without anything else . Please check > czcams.com/video/DQtVqsFCrMM/video.html
Ok, yes those gears mounted in an aluminium housing would be just fine. 👍 I could have done the same but decided as I needed a belt reduction I could do both the reduction and reversing in one go. No Gearbox was needed in my case and is lighter overall. The Nolan and air scooter both had additional gearboxes and flew just fine.
@@Ben-Dixey Thank you for your time replying to my messages .
How the coaxial helicopter take turns .. if it has no tail rotor?
I'm adding the yaw control vanes now, have a look at the airscooter 2 or Nolan helicopter it will explain more.
@@Ben-Dixey can u share the link where I get to see....
@@prash007more m.czcams.com/video/B21Xk6tNcBw/video.html
m.czcams.com/video/V8zqG4LRnrE/video.html
Can someone explain why "fixed pitch" is not deadly dangerous in the event of an engine failure?
It is incredibly dangerous, as once you lose engine power you lack the ability to do an autorotation, which is why I despise fixed pitch helicopters, I was hoping at least one of the rotors had variable pitch
Sincerely hope he's successfully ..alot going on their..homebuilt helio's are notorious ...I shall say no more. Auto rotation ?
@@davidvenable9257 There is no autorotation - it cannot safely be flown at any significant altitude, and the builder has acknowledged that.
you have built your own coffin, how lovely.
The rotor itself looks a bit scary just view how real helicopter blades are secured
The whole machine is scary by nature. There are many more videos since this one.
May I ask how fast does the blades turn.
I mean how much is the RPM of your blades?
Sure, the blades currently rotate at 700-750rpm. Tip speed around 530ft/sec. yet to be determined if this is the most efficient speed.
@@Ben-Dixey thank you Sir.
Do I need to make the rotation more faster if I make the blade smaller?
I mean does the smaller blade need more rotation?
Because the drone rotation is higher than a helicopter.
Adjustable Wrench DIY that's correct a smaller diameter rotor with a proportionate blade chord will have to rotate faster to maintain the same tip speed and therefore lift. If you increase the chord length on a blade you will be able to run it slower. This is why on big aeroplanes they extend the flaps in order to land at a slower speed, the same applies to helicopter blades, however there is an optimum chord length taking weight and drag into the equation. It is also true though that longer blades are more energy efficient than shorter ones to a point, it's more efficient to move a lot of air slower than a smaller amount of air faster.
@@Ben-Dixey thank you Sir.
I learned something new today.
@@Ben-Dixey How the coaxial helicopter take turns .. if it has no tail rotor?
Why do you use a wood to connecte the blades with the rotor?
Wood is just a material to take up the gap between blade straps and the blade. You could use any lightweight material within reason and it would do the same job. The bolts themselves are enough to take the tensile strength but the clamping force dramatically increases the strength of the joint.
@@Ben-Dixey oky good job bro!!and I can't wait to see the next video when your coaxial helicopter is flying.
i am From africa 🇪🇹 Ethiopia
How are you able to control yaw ?
Hi, yaw will be controlled by flaps directed left and right in the downwash mounted on the tail. I will soon be carrying out a ground run as the rotors are nearly finished. If that passes the required tests then I will start making the yaw controls.
@@Ben-Dixey 👍 ok
do you have a plan for it.. ?
Hi, sorry I'm not sure if you're asking do I have a set of plans or what is my plan in making this. To answer both I have no set of plans I have designed it from scratch and my reason for building was to see if I could and to learn from the experience.
There is a better way for the belt drives.
What's the better way ?
@@Ben-Dixey I really admire what you have done.
Better, only if using two identical belts is better?
This man is using two identical belts.
czcams.com/video/JQDcx7wuHIc/video.html
That means he has a small gearbox with two small gears meshing together.
Only one gear is driven the other one just follows it
That means they turn in opposite directions.
Each gear then has a pulley on it's shaft for driving a belt.
So instead of two idlers, you have two gears.
Is that better?
How does it yaw as there is no blade pitch?
Hi, There will be directional fins on the tail. If you search Nolan helicopter on CZcams there's a really good demo of how it works.
@@Ben-Dixey Thank for your quick response. I am thinking building RC type of your.
@@Ben-Dixey czcams.com/video/B21Xk6tNcBw/video.html I can see it here. now I understand.
@@Ben-Dixey I have another question. what about the collective pitch for thrust up? is it depend on engine RPM?
Yes, engine rpm is used for controlling altitude, there's no in flight controlled collective pitch only ground adjustable. There's a guy who's made an rc version check out m.czcams.com/video/X2gcgRWOAOw/video.html
I have a engine 970cc
Max power 5500 rpm
Torque 72/3000 Nm
please suggest me main pulley diameter ant tooth,
The gear ratio depends on the rotor tip speed you want to run at, my next test is going to be with a tip speed of 515ft/second. To answer your question I would need to know your rotor diameter and tip speed chosen. My next test is going to be with a ratio of 7:1 20 teeth on the driving pulley 140 teeth on the driven. The belt is 8mm pitch so the driving pulley is approximately 51mm and the driven pulley is approximately 356mm, to get the exact diameters I would have to look at the toothed pulley table.
@@Ben-Dixey Right now I am just gathering information, I do not have any plan, now I am an automobile technician, so apart from the engine, I am thinking of making all the parts myself and the blade that too just because your design looks simple.
Клёво, а что за двигатель на нём стоит?
И автомата перекоса нет?😳🤔
Hi The engine is a 60hp Johnson outboard 2 stroke 2 cylinder. The is no swash plate as the whole rotor mast pivots providing the cyclic pitch control. Have a look at the Nolan brothers eagles perch or Air scooter 2 on youtube these are the machines that demonstrate the tilting mast. Thanks
@@Ben-Dixey Hi, а как тогда шаг газ? Как меняется угол атаки лопастей при подъёме и снижении? Я чёт не врубаюсь 🤔
@@user-eu8ij8io5y Есть только общий шаг, а циклического нет. Его заменяет наклон всей колонки на кардане.
@@erwe1054 ну это я понял, а как обстоят дела с дефференциальными шагами винтов?🤔 Во блин головняк😏😀
@@user-eu8ij8io5y Я тебе наврал ))
даже общего шага нет, все рулится только режимом двигателя. И диф .шаг отсутствует - поворот производится за счет наклонных рулей, обдуваемых потоком от несущего винта.
Boa tarde sou do Brasil você me vende o projeto
Hi thanks for the interest. I'm going to keep it for the foreseeable future. No plans to sell at the moment.
No swash plate? Sure this is even possible?
I used to have a larger coaxial toy with cyclic on the bottom: It was very limited and would crash if you made it go fast because there was no way to control it in that state.
The concept has been proven to some degree with the airscooter 2, Nolan helicopter and Bensen b9, the Bensen is the closest to mine but flight details are vague, built in the 1950s. There is an element of the unknown with this project.
what is engine name
The engine is a Johnson
Where is the collective control?
There isn't any collective control, the blades are fixed pitch and rely on rotor rpm to control altitude.
@@Ben-Dixey Sounds deadly dangerous if an engine fails.
Ram Jet yes, if it were to be flown at an altitude higher than a few feet it would be dangerous. This is why I think the air scooter was never sold, if there were two engines or collective control then it would be safe to fly at altitude but my goal was to build something to hover around a field on this occasion.
Автомата перекоса нет?
Hi. No swash plate, cyclic control is through a tilting mast on hinges. The same control as on the Nolan or bensen b9 coaxial helicopters.
@@Ben-Dixey понятно, меня интересует Рама вертолета и редуктор, из какого материала они сделаны? Алюминий?🙂
@@Ben-Dixey здравствуйте! А можно узнать размеры ремней и самого редуктора и передаточное число редуктора?
Одинокий Волк the ratio I'm going for now is 7:1 but it's the blade tip speed you want to run at that determines the gear ratio. My belts are 8mm pitch gt2 poly chain by gates. One is 36mm wide the other is 45mm that's because the double sided belt was only available in a width of 45mm but 36mm is strong enough to take the hp.
@@Ben-Dixey спасибо за ответ, ваш вертолет уже отрывался от Земли? Как обстоят дела с авторотацией?
That thing looks so scary all bolted together, not a good idea.
Air frames are bolted or riveted together in aluminium because of fatigue cracking at welded joints. Virtually all gyrocopters have a bolted aluminium frame for this reason. Rotorcraft experience high levels of vibration when compared to fixed wing and a bolted aluminium frame is the safest solution.