Homemade Helicopter Rebuild part 2 plus Wing in ground effect, Ekranoplan, flying boat
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- Опубліковано 5 жов 2024
- Fixing my helicopter by going through an important design decision, we can help each other by sharing information and discussing the issues.
- Наука та технологія
A lot of people on here take this construction to serious, this a amature project of a flying device/machine, its not going to be a certified helicopter flying 100s of feet for 1000 s of hours, its for the ocasional hop around a private field wich be a great achievment ! I dont think Ben is planning going on his holidays in it.
Thank you and well said. 👍
Years ago I made most of the parts necessary for a minicopter. I never got around to put the parts together. Put an ad in the paper and someone else bought all the parts. That was the last time I seen all the machined parts I made years ago.
Wish I did not sell the parts today. But it is too late, its gone.
Nice work fella.
Interesting 👍 Was it parts made from online plans or your own design ?
@@Ben-Dixey Hello Ben. I made the parts from my own design. I looked up components comercelly and improved on the technical and duty cycle. So I cheated a little bit fella. Parts were 7078-T8 aluminum. The shafting was high grade titanium, I do not remember the grade Sir. Like your video. Brought back a lot of great memories. Peace v
Helicopters commonly use multiple belts (5 or 6), not the toothed ones as you are using now but regular V-groove belts. Yes they might slip, but in a way this could be a safety feature by absorbing peak loads. In some helicopters (Rotorway Exec) a belt tensioner is used as a rudimentary clutch. To me this feels a lot safer than a chain drive and due to having multiple belts you also have some redundancy.
With multiple v belts the whole unit becomes tends to become very large and cumbersome, not possible on Ben's machine.
A Vee belt drive would be very nice as you suggest, the sch2a uses a multi rib flat belt, nothing special from what I can gather. PK optibelt, very surprised it can take the load. Double sided Vee belts could work for me but a few of them needed for each drive, as mentioned weight and size could be a problem. Great comments coming in, really helps.
From reading through CASA crash reports, mostly for Robinson's the most common cause of helicopters coming down was drive belt failure due to slippage or breakage. Second most common was overheating engines. Multiple vee belts are used because they are a CHEAP means of transmitting power.
Don't forget to factor in adrenaline strength when designing your control system. I guarantee you that you can pull twice as hard as you can when you're not flooded with the good stuff. I'm so glad you came back to the helicopter project! Sometimes it just takes a while away from something to get a clear perspective on the path forward.
That's true, Adrenalin definitely gives you extra strength, I'll check the calculations with double the pull. 👍
Chains don't have any elastic properties. Heat is your enemy the chain will get very hot then the links will loosen and the chain will go slack. The way to mitigate this is to use 2 chains and 4 sprockets or more to spread the load over them and lower the heat and aide cooling. However I do agree with av8tor261 chains are a bad idea on a helicoptor. I am a race car engineer and have used chains on bike engine cars one 20min race would still see both the chains loose tention and after 5 race's the chines would need replacing or they would jump of the sprockets due to throttle changes that would induce backlash in the chain with the loading and unloading of power not good for long duration flights. But you might be able to use multiple belts in the same way. Ask av8tor261 for some advice he has all the expertise in this field. Ben don't get hurt if a chain snaps it will detonate the rotor assembly.
how do race bikes get around this? And Rotorway helicopters use a chain reduction drive, so they must have figured it out too. maybe cause they use a 3-gang chain
@@licencetoswill Bikes are light not as much load plus they have chain tensioners. Things that fly not my area of expertise but a single motorbike chain is not the way mybe there are specialized chains for helicopters.
Hi, the chain that was used in your race car example do you know how stressed the chain was ? What size chain was it, how much chain tension did it experience? A chain getting hot is my worry particularly on the bottom drive because it's being reversed 4 times instead of two. The chain tension is quite low and under stressed but the speed is quite high. Thanks
The more i watch your videos the more i wish to build mine..... thanks for the inspiration. It worth the wait keep on the good work ❤
You are extremely talented. I'm so glad you didn't give up.
I think when factoring weight of the system, comparing belts & chains, you need to factor in the weight of the guards you need to protect life & limb from a catastrophic chain failure, which could take out any & all of of your body, the fuel tank or the rotor blades if an unprotected chain lets go, compared with the more benign catastrophic failure modes of belts...
Chains breaking must be avoided, just like belts breaking and gearboxes breaking up. The correct design decision needs to be made.
Another great video Ben! I would think a 520 chain would be fine the stark varg dirt bikes make 80hp with those chains. But also chains don’t like running on there side I have heard, maybe the 530 is the right choice. Also the chain drive is more efficient right?
Good point about chains running on their side. Rotorway did this and ran them on their side. They were in an oil bath and were triple chains. Think it was high maintenance and they changed it to synchronous belt drive.
They were running them much slower than mine but at much higher torque.
Not sure what the right decision is at the moment. Seems to be a hot topic 😆
@@Ben-Dixey I read through the comments and wow a lot of hate on the chains haha , also keyboard warriors that haven’t built anything close to a coaxial helicopter giving advice . I imagine you spend a lot of time thinking about it looking forward to see what you do
On cables, just make sure that they are not bending on either end. cables must pull straight. You probably know this, but I thought I would remind you to double check. There have been many an incident where failure occurred. Love the build my man!
Hi, bending on the end ? Is this when people don't allow the thimble to rotate as it pulls bending the cable ?
I don’t build helicopters but I think I would use dyneema cord. And a tensioner in a place where it needs a very small spring. You can make loops using the classic ‘two sweethearts’ knot. Very strong indeed. If you don’t want to run over pulleys maybe bent and flared sections of seamless pipe are an option. But then you should look up if dyneema can tolerate that.
Another great video. I concur with your decision to use chain as well as the selection methodology.
A few people have mentioned heating, stretch & wear in relation to chain. They are all valid concerns - but by periodically inspecting the drive components, you should be able to determine a life expectancy for each component and thus a service / replacement schedule. That approach is common in aviation where strength / life expectancy have to be balanced against mass. Sometimes the most viable solution is to have a light weight part, replaced often.
Great comment and that makes sense to me. The chains are cheap and can be replaced every 10 hours of operation if necessary. I think considering the low stress the chains are under it will be a reliable option.
Thanks for the video Ben! I am in the stages of wiring my instrument cluster together and getting it ready for the next stage of testing signal leads from different components. I will make a video soon. Once I get to a stopping point on the electronics I will be installing the swash plate and roughing in the controls to that point. Then, it's off to installing the turbine engine!! Keep your vids coming brother. It's fun to watch all the things you are doing.
Thank you and I look forward to your updated video. You do very nice work and you are going to have a superb machine at the end of it.
extra-extra deep grooves for the control surface cable pulleys to help prevent cables coming off the pulleys perhaps?
I did consider that option but decided to use a cable retainer instead. A bent bit of metal that almost contacts the diameter of the pulley, preventing the cable from coming off. It's usually a U shaped bit of metal that is bolted through the pulley bolt but it needs to be done so that if the pulley bolt came loose it can't rotate and jam the cable.
That's the thing with some safety devices sometimes they can cause a failure rather than prevent one. It's easy to solve that issue with an additional small bolt.
G'day,
Yay Team !
I flew behind a Bicycle Chain in 1978, and that Chain had been flying since 1975, with a 1-cylinder 2-Stroke
"Pixie Minor" 8-hp ex-Lawnmower motor
Pulsing and vibrating it into motion.
This past 6 weeks I've put 670 Km on the new Talaria Sting L-1-e..., a 3,000 Watt road-registered Electric Motocross Bike.
It has the biggest Bike-Chain I ever owned ; and I'm coming up to speed on it, but it works very well.
People have been making ,& using Chains to transmit Power for a hell of a lot of time ; and basically all the Bugs any Armchair Speculatir can imagine were all thoroughly solved a hundred years ago.
Wilbour & Orville used Chains in 1903 to not only drive two Propellers from one 12.5 Hp Engine - but also they ran the Chains through Guide-Tubes, to eliminate Chain-Slap - and one Chain & it's Guides were "crossed" so that the 2 Propellers could rotate in opposite directions.
Chains are an efficient, cheap, &😮 reliable option.
Chains do fail, when badly made, or badly aligned, or badly maintained...; or when overloaded...
But no more than does anything else.
The trick is to do it
PROPERLY, and thenceforth
Thou shalt
Not
Upfcukificate...(!).
One factoid cometh to mind..., when subjected to Thermal Analysis, a Bicycle Chain is 98.5% Thermally Efficient.
They waste almost no Kinetic Energy in heating themsrlves up from excess friction.
Such is life,
Have a good one...
Stat safe.
;-p
Ciao !
Brilliant comment. Thanks 👍
If you look up the IWIS and DID chain catalogues they will tell you the ultimate chain tension before breaking. Ideally keep it helow 10% for indefinite life. Motorcycle chains are designed as a service item, they often run in the 30-50% range of their rating (at full power) causing them to stretch over time. Most of the bike chains are sealed with lubricant, but an oil bath or squirter would make it last longer. Read about chain cordal effect also, the smaller the sprocket the worse it is. Generally 17+ teeth is where it disappears. I beleive the IWIS catalogue also informs you about lubrication, but as already mentioned an oil bath or squirters are for indefinite use, a few hours/days does not require the same intensity of oiling. If you want the best chain, go Ramsey RPV (Morse), although it would require an enclosed housing. Just remember chains are very dangerous.
Brilliant comment John, Your knowledge is unreal. Will look into what you have said. 👍👍
@@Ben-Dixey Sounds a little sarcastic, I suppose people telling you chains are dangerous is a little obvious. Keep at it, ignore the haters.
@@chippyjohn1 I checked the tensile strength of a 530 DID chain and is was 8500lbs, the chain load on the helicopter will be 400lbs on each chain. The chains are 20x stronger than the maximum constant running load. Not a bad factor of safety I'd say, cant imagine how a chain could. break under those conditions. They will probably need to be replaced because of wear long before they broke. Would you agree John ?
@Ben-Dixey First point of concern would be the 8 tooth drive sprocket, too low. need to read about chordal effect and what percentage it is. Chordal effect is when the chain rises and falls from the sprocket engaging the chain, it will create vibration and pulsating torque. Wrapping around the idlers might be an issue. Ideally sprockets should be uneven teeth as chain should be even giving a hunting ratio, but you won't run it for long enough to worry. Strength will be fine for the 530, even with the addition of slight centrifugal tension. Obviously just keep an eye on wear and do some periodic oiling and check for heat. There are plenty of quality dry film lubricants for chains that will last much longer without the addition of mud and dust etc. I initially looked at roller chain for my project, but i was constantly chasing my tail trying to make it work. Rotorway did have issues with chordal effect, lubrication both prior to starting and while running, drive shafts breaking, sprocket wear, tensioner issues, and weight. Once again, chordal action will be your biggest issue.
@@chippyjohn1 Brilliant comment as always. I did briefly read about the chordal effect, will read some more. It sounds like chains aren't going to work for me then as I don't want a bigger drive sprocket than 8T. I know the Bensen B9 used a chain drive and this was one of the reasons I thought it might work. Out of interest I'll try and find out what ratio that was but it's sounding like a no go. The extra heat from the lower chain going around idlers could be an issue too. What drive did you decide on for yours ?
Wonderfully explained. Even without math i would have gone with a 1000cc sports bike chain, instead of the 250 one. 👍👍
Great to see an update on the "Seakranoflyer"
👍 Seakranoflyer 🤣🤣 love that name.
@@Ben-Dixey Glad you do. Keep up the Great job 👍👍
Be careful - roller chains really don't like to be run horizontally - you'll find a lot of wear on the side plates and sprocket teeth as the weight of the chain pulls down on the sprocket.
Thanks for the insight, much appreciated, makes sense. 👍
There is a school of thought that prefers an elastomeric coupler btw engine and reduction driven propeller when using gear drives. I assume the same might apply to chain drives.
I'm not aware of any flying examples using a chain drive propeller speed reducer, however I have seen them on prototype layouts.
Yes, that's right a cushion drive is important. I have no doubt more so if using a chain that has some play back and fourth.
I see homemade helicopter, I hit the like button! 👍🏼
be aware of chain strech, a common matanance requirement on motorbikes is to re-tension your chain as it stretches over time.
👍 chains could stretch quite quickly in this situation. Granted
Wow !! ya know what? I really should do a reaction series on your journeys. Hells bells my friend, there's some complex stuff going on here but as usual, you are attacking this with aplomb! Great job Ben!
Thanks a lot Tyger, would love it if you did a reaction video. Had to look up what aplomb meant 😆 don't think I've come across that word before. 👍
Hello sir, I believe going to Chain drive is a mistake chains are designed for running horizontal not vertical as your belt s run now , I've worked on equipment and vertical Chains aren't used they get turned into gears, chains aren't made to run that way they have a side thrust issue, not trying to burst your bubble as they say just offering input, if you do go chains I would bet it tears up gears , sorry for that, but I'm thinking I'm right, goog luck it looks really good from what I can see on video
Thanks for your input, I've found a couple examples where chains runs in the same way as my belt drive. The Rotorway Exec helicopter used chains and the Bensen B9 Helicopter both run horizontally. I don't think it will be a major problem but I need to do some more research and can understand why it will wear one side of the sprockets. It just depends how fast the sprockets wear. I suspect the driving sprocket will be ok because they are hardened but the driven sprockets I want to use Aluminium. This sprocket might wear, it just depends how fast.
i'm curious about running chains in a horizontal situation at higher speeds given gravity will be pulling them sideways to the plane of the sprockets.
yapdığın milin vidası nekadar sağlam bilmiyorum ama o mildeki 3 gen metal parça kırılmasada bu dönüm vidalarda sorun olabilir kolay gelsin
good call on the chains! i'm glad your back & cant wait for the new copter!
BAH HA HA HA!!!!! You don't know anything. Worst thing ever are chains for this. Genius.
@@X-Christian-464 you suck at trolling
@@X-Christian-464 would love to hear why you say chains are the worst idea ever.
@@Ben-Dixey Because common sense. Grey matter. Wisdom. As Yoda once said; Chances take, do not!
@@X-Christian-464 That's your answer, common sense? 🤣
Chain drive makes a lot of sense, Ben. You could consider replacing pivot currently below rotor with 4 bar linkage to put virtual pivot between both rotors to improve cyclic response (needs some thought for yaw alignment). Also you could control collective pitch of lower rotor then have lower rotor controlling collective pitch of top rotor to improve collective response. Collective pitch only would be relatively easy to retrofit using sliding collars with bearings to allow different rotation directions.
The pivoting rotor head, with teetering for each rotor, works well enough to my mind. But, if you wanted to go full cyclic swash plate then lower rotor controlling upper rotor could work too. You just end up with a swashplate in between the rotors.
Any thoughts about differential rotor rpm control to improve yaw response? Did you get any turns in before the technical?
Hi Martin, yes that's right a four bar linkage Would move the pivot point nicely. The challenge would be keeping all the links free of play and strong enough to handle the rotational torque from the jack shaft. If it was doable though it would definitely make a big difference to how the cyclic feels.
Collective as you suggest would be easy enough I think to implement.
Differential rotor speed would require the rotors to be driven by a differential. The Bensen B9 did this and braked one rotor. I believe it caused the machine to sink.
Rotor tip brakes is another option for yaw, little flaps that extend on the end of the rotor blades. Apparently they don't cause the machine to sink in use.
Would be simple to install will electric servos.
The downwash vanes have worked ok so far but need more testing, I seem to remember once running out of authority but I can't be sure
@@Ben-Dixey , sounds good, Ben. I'll have a think about 4-bar linkages and see if I can come up with something. It might need a subframe to separate pitch from roll to keep the play down and strength up. Lets see if I can think of something simple to implement though.
I'm also thinking you have what you needs on WIGE for now? Let me know if that isn't the case. I'm using the time to focus on my own battery project... 😉
@@martingarrish4082 might take some thinking about Martin. Yes, got everything at the moment thank you. Your help has been brilliant.
I have a concern about the helicopter rotor blade straps. I chose to make them from 7075t6 but I'm wondering if steel would have been a better option. Blade straps on the rotorway are steel with an aluminium hub. Would like your thoughts at some point as I'm worried about fatigue.
To avoid frame flex and cable length issues, have you thought about sleeved cables like push bikes used?
I haven't considered that no. I suppose because I haven't seen them used on aircraft. Perhaps for inspection purposes.
Great feeling to see you back on the main project brother. the full success isnt far away now . thanks for sharing with us,
Cheers my friend, I've got to finish the flying boat before really concentrating on the helicopter but can't wait to get back on it properly. I really don't mind dedicating the foreseeable future on the helicopter. Its worth it because of how rewarding it is.
@@Ben-Dixey to me the most exciting part is to plan ,build , create, to puzzle, to struggle, to tests the thing it's even good to have two projects in the hand .
There is no chance of hitting boredom in your life until both projects get it destination.
Is flying boat like fixes wing aircraft or it's just a air boat ?
Full support brother
@@rajeevshagun7409 👍 yes, I agree, there is a lot of satisfaction in all aspects of the builds.
The flying boat will be an aircraft that flies in ground effect. Height above the water will be somewhere between 2 and 6 meters. It will be similar to flying a plane but can't climb very high, it relies on the extra efficiency of ground effect to fly. I think it will be a lot of fun if it works out. Cruise Speed will be 40-60mph, faster than most boats but only 60hp.
@@Ben-Dixey I want to use your helicopter lifting off footage in the reels , ofcourse your name will be displayed as a creater of the machine, if you permit me to do so ?
Because I saw similar DIY coaxial helicopter in Reels just now , it too had extra tubes for primary balance support.
Thanks brother 😊
@@rajeevshagun7409 Sure, no problem 👍👌 I'm all for sharing.
im son of the craftsman but as much as I like this I just dont think I have the mechanical engineering skills to keep it safely maintained. oh and , can we get away from belts???
what about like the gyro copter with the run up cable like a weed eater cable?
Best bit was 7:36 where we all got to see you twiddling your joystick, one handed!
Chains will work, but just like belts the more times it changes direction the more wear that will accumulate. At this point you should just go ahead and engineer and build a full gearbox. :D You got this!
Yes, that's spot on. The bottom chain will be going around two idlers and will heat up/wear much more quickly than the top chain. Will it be a problem ? I don't know, I would love to build a gearbox for it and ultimately that could be the right choice. Weight needs to be taking into consideration though.
@@Ben-Dixey Maybe you could just fab an enclosure for the lower chain drive and mist it with lube. No longer than you fly, and with the light loading that should suffice.
@@helicopterdriver yep, that might work. 👍
@Ben-Dixey zip tie in place a can of castrolOR motorcycle chain oil and rig it up so some opporator input automatically activates it at a useful interval.
Make a spray or two during preflight a habit.
multi-rib flat belts, or... crazy talk? a planetary. either the gear set from an automatic, or make one with a bunch of pneumatic tyres aka rollers...
Hi, multi rib belts can work and could be a better option. The sch2a uses multi-rib pk belts. I was very surprised when i saw them being used. One is run on the backside of the belt against the big pulley. This means it doesn't have to be double sided. A small diameter drive pulley is used.
Planetary gear set from an automatic would be a good option. Think it can be used for torque balancing two rotors.
Chain drive will transmit vibrations from the motor to the rotor and vice versa, I don't think it is a good idea- what other helicopters are chain drive? Most of them use belts right?
They use belts sometimes for the primary drive
Rotorway used chains for a long time but went to a synchronous belt drive.
Chain drive, when braking, could broke or jam whole assembly. Broken belt cannot do it. I been riding speedway bikes way back, when primary chain (same speed like helicopter assembly) broke, it will cause heavy damage. You have chain whip, with enormous power to do heavy damage.....
Yes a chain breaking would be catastrophic. A belt breaking would also be catastrophic, all the power would be transferred to a single rotor and the machine would violently spin as it dropped. The drive breaking has to be avoided so I need to choose the right path. Can you tell me anything about why the speedway bike chains broke ? We're they being over stressed ?
be carefull of divided attention between the 2 projects
Bike chains aren't used laying on their side.
That's right, not normally anyway. You would think that considering the tension they are under it wouldn't make a significant difference but maybe it does. Need to research this.
Your calculations based on the use of a chain in motorcycles may be correct but do realize that a motorcycle is rarely driven at top speed if at all. In your application, the chain is used near maximum loading most of the time. A 1:8 ratio would require one rather small and one quite large wheel. There is a minimum number of teeth for the small chainwheel. The big one will be very big.
Imagine the stress on a chain when you rev the bike up and drop the clutch at the lights with 2 people up trying be the first away the chain takes more than they specifie .
Hi, the 530 chain on the CBR at maximum load will be 2561lbs, the same chain will have a chain pull of 808lbs on the helicopter. The maximum speed on the CBR will have a chain speed of 25.7m/s and the helicopter will be at 12.7m/s. I understand the chain speed is still high for a constant use situation but I do think that the temperatures will be manageable for short durations.
problem with chain if it breaks at the wrong spot of the chopper sprocket there is a very good chance it jams the rotor assembly not good or even worst it breaks and hits you still not good use the belt if not the exact one you use try one thats aero certified or race car certified cheers from down under
Correct on all counts. But you know that all the great brilliant minds here that have changed civilization all think the chain is a great idea.
I don't understand why a chain would break if it's not being overstressed.
@@Ben-Dixey a chain does get stressed maybe nut in stretching but in lateral and vertical stretch when a chain is laid on its side under rpm but that’s your choice
@@glennarnold3970 Ok, yes this needs to be considered. I've got quite a long distance between pulley centres, running the chain horizontally needs to be researched. Thanks
@@Ben-Dixey just trying to give you options cheers glenn
I wonder how many CAA crash reports start with ‘Homemade’… 🤔
Bound to be a few.
Not a helicopter but a gyrocopter, no tail fin or adjustable pitch.
Its a helicopter, no tail rotor needed as its a coaxial rotor.
My friend, which country are you from ?
I'm from the UK
@@Ben-Dixey I am pleased with you.. Did you fly the plane.. Why is it not balanced..?
Helicopter pilot/engineer here. NEVER USE CHAIN DRIVE!
You should tell everyone why
@@opieshomeshop so is the concern that a chain could jam everything up?
I reckon with a contra rotating heli like this if a belt falls off he's fucked too haha
@@opieshomeshop The Cv joint didn't fail.
@@opieshomeshop Please explain why the chain will fail and I will listen.
@@opieshomeshop The part I made to hold the cv joint on broke not the cv joint itself. There was nothing wrong with the cv joint.
chain !
put big end plates on ur wig wings
It's a good idea to reduce the tip vortices, will see what I can come up with 👍
@@Ben-Dixey also to trap as much air as pos under the wing
When the motorcycle chain fails, you at worst fall off the bike. When your helicopter chain fails, you die.
That being said, my dad swears by his Scott Oiler on his chains for his superbikes.
@@RobinDuckettMore risk than a motorbike for sure but bare in mind maximum height for this machine will be around 3ft. Chains have been used for helicopters. Rotorway for example.
Interesting about the oiler, that could be a good addition.
Oof, didn’t realise they were £300! Definitely not the price he told my mum back in the day 😂😂
Looks dangerous
Before you destroy all your work, you may want to become expert first by spending 4,000 hours in a sim.
I'm not joking.
If you've spent less than 1,000 hours in a sim, or none at all, hang up your hat, and learn to fly first, or you're going to be chopping up grass or worse. I'm sure you've seen plenty of vids on pewtewb of homemade microchoppers augering in because of lack of experience.
The different between me at 200 hours, 500 hours, 1000 hours, 2000 hours, and 4000 hours was worlds beyond in each case. At each new level, I'd look back and when I thought I was totally qualified to fly, and say nope, not at all.
At 200 hours you can sort of fly and you think you can fly. Pfft. Maybe like a G.A. sorwwy pilot.
At 2,000 hours and beyond, you don't fly any more, you swim through the air like a minnow.
It sounds like you are a very experienced pilot. I'm very happy to have what instruction I can afford. To have 1000+ hours of instruction before going further might be considered a little odd considering what I've already been doing. No one can really argue with your comment but it does seem to be extreme, particularly when I'm flying a very unconventional, unproven design that can't even autorotate. A simulator would be good for training in an R22 but an R22 and my machine are worlds apart. Perhaps like using an F1 car simulator in order to learn how to drive a tractor.
Could always put 2 chain wheels and chains, half the load..
Correct, redundancy as you know is a great thing but the extra weight also has to be considered.