@@airgunningyup Thank you. I noticed a comment from you on a really early video, you've been watching for a few years. Thanks for the continued support.
LOL, Inspector Gadget.. That takes me back, did not expect you to whistle that. Love the format with you in front of the camera. It really does make me feel as though I'm now part of the conversation, almost in your shop.. Great looking engineering.. Kindly Ryn..
@RynCarmichael Really appreciate the feedback. 😊👍 It's been a long time since I watched inspector gadget, I have no idea why that tune came into my head after so long but I hoped it would get noticed. 😆
Hey brother Ben, thanks a lot for letting be the part of your developments , your upgraded new designed drive shaft is really looks trouble free . lots of little parts and components has been designed and made really well. as i always tell you i really enjoy to watch the improvements and developments rather then Done it and fly and forget . nothing late or delayed , you are doing what you love to do and we are watching which we love to watch. will see how this drive shaft will behave , will it need enough lubrication on that new designed expending in and outer tube as well as the bolts moving area where they will go bit up or down in the slits ? thanks again
@@rajeevshagun7409 Hi and thanks for watching and the lovely comments. 😊 I hope the driveshaft will work but it's a new concept and it's uncertain. If it doesn't then I'll change it for another idea. The bolts will be replaced with rollers and they will be lubricated, there will be no contact between the inner and outer sliding tubes other than through the rollers. The next video will explain it further.
@@rajeevshagun7409 yes, the previous shaft I made was hollow. As I expect you know the material in the middle of a shaft just adds weight and doesn't give much more strength.
@Ben-Dixey okay ,, When you said if shaft is not hollow, the middle material don't add the strength but just add extra weight, Does this rule applies for particular metal or all metals ?
@ All metals, it's to do with the polar moment of inertia. The further away the material is from the centre of rotation the more resistant to twisting it becomes. Like you will see on a vehicle propshaft, the tube driving a vehicle is quite large in diameter and is thin walled tubing. It's lightweight and strong. Helicopter rotor shafts are tubular for the same reason. The polar moment of inertia is relatively simple to calculate but there are online calculators to tell you which is even easier. It allows you to calculate the strength of a bit of tube and how much stress it's under. Different materials have different limits to stress levels.
brother Ben you look absolutely good presenting front of the camera , this is my first impression about this video , rest i will write in second comment thanks
you are a natural on camera, not to worry at all. Tell us again why a splined shaft would not work as a drive shaft ? It would need to be close fitting but that's possible.
G'day Ben, Yay Team ! Outstanding stuff, absolutely wonderful... My recent highpoint was scoring a spare new Battery for the Sting, at $1,010 instead of $2,010..., as an "Xmas Sale Special" ; the Box was sealed at the Factory in Hong Kong in March 2024 & that Sticker has a 16/10 overstamp - my guess is that's when it was shipped (?) ; and it arrived via Contractor (at an extra $190 for the 630 Km...), fully-charged... So I deduce that the Importer opens the Boxes and maintenance-charges them on the Shelf every month, discounts them about 9 months after manufacture, and probably ships them back if they're unsold a year after leaving the Factory (?). The Trumpocalypse appears to be unfolding at a very great, and accelerating rate of fulmination...; but Thwaites Glacier's Sea-Ice Tongue broke up the week before last, so maybe the Accelerationists are currently racing to see if they can shut down Industrialisation before Sea-Level Rise beats them, to the execution... ? Interesting times. Such is life, Have a good one..... Stay safe. ;-p Ciao !
I like how you describe the control method as like a gyrocopter. It looks like just a weight shift but it's proper cyclic pitch control. My RC helicopter using this had the same handling as one with a swashplate. I hope the new drive shaft works.😀
@@mitubachiflight Hi, yes I do believe a tilting fixed pitch rotor is cyclic control. That's what all the gyrocopter pilots say and I can understand the explanations to why it's the case. There is one difference though and you might not have noticed on the model you built. The distance from the pivot point to the top rotor means that the top rotor does more lateral movement than titling. The top rotor can't provide the powered titling like the bottom rotor so it resists and therefore more weight shift is going on. With small inputs you wouldn't really notice but any large or abrupt input requires significantly more cyclic stick force than a gyrocopter would. I haven't experienced flying a gyrocopter personally but have had conversations with people who fly both helicopters and gyrocopters and they say there is no force like I describe in a gyro. If the pivot point was in the centre of the two rotors this force would be reduced. It's so nice to watch your model flying around, gives hope that the full scale I've built could too.
@@Ben-Dixey Thank you for sharing your fascinating story about the feel of the control stick, which you can only understand by actually holding it. So my servo motor is fighting against those forces! My RC helicopters have had many failures. I'm glad it's a model. I wish you a safe flight.😀
@Ben-Dixey good stuff man, your project is fascinating. I should let you know I'm a RNZAF helicopter pilot. When watching I thought these factors might help: Hover on perfectly level ground, the slope causes the downwash to flow downhill which creates a drift which you have to correct. Hover at least 3-5 rotor disc diameters away from those hedges and trees, those obstacles cause the downwash to recirculate on that side which causes a drift towards the obstacle. And the obstacles cause the wind to tumble into your rotor disc generally destabilising you so no nearby surrounds at all is always better. Unsure if you were nose into wind there but that always helps directional stability. The best advice I got learning for hover was "consciously halve your control inputs. So extremely gentle because most of the time we are actually.just correcting our own inputs".
@@j6077xxd wow, I didn't know these effects, thanks so much for sharing the info. I'll see if I can find a better, more level area in the field and also get as far away from hedges and trees as I can.
Hey Ben....for the circlip grooves I thought either a woodruff cutter like how you did it, or making a mandrel to go all the way through the U joint to mount in the lathe and grinding up a special tool. What about a tractor PTO shaft spline for the plunging of the driveshaft?
@@ollied1981 Hi, great idea on turning a mandrel for the lathe, didn't think of doing it that way. 👌 From the static testing I've done splines have too much sliding friction, but I haven't tried a dynamic spline friction test. My feeling is static or dynamic the result would be the same but I could be wrong.
Grinding my teeth over the complexity of that shaft... Of my whole design, my driveshaft gives me the most anxiety and its a very simple static transfer compared to yours. Resonance between the crank and the prop scares the shit out of me, it can snap a crankshaft in seconds. The math is way above most to calculate with harmonic orders etc.... Way above my head so I put all my effort into aiming for zero lash and hoping for the best (not tested yet) On the upside, if you hit a bad one it will find any weak spot very quickly, if its not so serious, you ought to be able to see any hammering after your first tests (or it will gain slop that you can feel if you cant see the interfaces) PS: Fits: Interference fit, slip fit and badgers arse :)
@@pimplequeen2 Hi, what are you driving with your driveshaft ? I've seen a propeller snap a crank shaft due to the lack of a flexible drive coupling between the two. Resonant vibrations is a concern but until I start testing I won't know. Like you say it will be easy to inspect for any hammering of drive faces. I will keep the backlash to the absolute minimum.
@ Three axis Sub 70kg pusher contraption. (think I sent you a link to an image way back... Very rustic cable braced fixed wing) The potential for destructive resonance is always there. When the boffins attempt to deal with it, they often attempt to hit the first order at low rpm (maybe even sub tick-over rpm) quickly passing through the second order into climb rpm or cruise rpm (Where all the power is) and never reaching another. Zero lash prevents any hammering we might get form less destructive harmonics. Apparently, the less destructive resonances can be heard / felt so avoided in standard use... for example, I drive a sprinter van that has a resonance at certain rpm's, I avoid that rpm to prevent the obvious wear (cant be arsed hunting it down and fixing it) A reasonable analogue for catastrophic resonance is a skidding roller bearing or a bearing that squeal's... They can absorb huge amounts of energy in short order resulting in snapped shafts. The point is, Its a tad technical for us shed dwellers so we can only really pull the trigger and see what happens. Any sudden mystery damage (snapped crank, blown prop shaft etc) is likely to be a destructive resonance event and all we can do is change the mass of the crank or propeller or stiffness (amount of spring between the two) to shift its onset. Stiffer = higher frequency resonance.
@ Just to max out your anxiety :) Baileys paramotors (four stroke singe) had issues with crank damage. (I have three of these engines) I cant find any definitive information on what they thought the issue was... I "think" they then added flex with rubber washers sandwiching the standard Helix propellers (Removed for the lighter E-props) and stipulate a high tick-over 2600rpm. Most paramotors use ribbed drive belts instead of toothed belts so if any resonance goes turbo, the belt will have "some" capacity to slip. Propeller-crank resonance is an issue that is commonly overlooked by us shed dwellers, there isn't much we can do but be aware and try to respond to signs. Assuming your blades can articulate on the hub, I would exclude their mass from consideration as they are likely to float any high frequency and dampen any low frequency resonance... Just worry about the mass between the hub and crank. BUT, what do I know, I am a shed dweller with just enough knowledge to be a danger to myself :)
Dear Ben, great to see you continuing to work on that project. Will you stick to fix pitch tilt head, or switch to a swash plate? If you stick to fix pitch, will you change the pivot point?
Hi, collective pitch would be the right thing to do long term, it maybe possible to implement that and keep the rotor tilting. That would mean I don't need the double swash plates. The pivot point you mention are you referring to an offset hinge like the benson b9 and gyrocopters ?
@@Ben-Dixey Its hard to imagine that the complexities of a drive shaft could drive a person to tackle swash plates but having watched some of your vids... I can see why it might :)
@ I have had such issues force me into incrementally designing two almost different aircraft... New issue on design A throws the advantage back onto design B. The lack of a definitive solution means chasing our tail... Round and round! Took me a long time to break out of the deadlock, put the pen down and start actually machining one of the solutions. It wasn't easy. Not many actually fire up the lathe risk the bucket of scrap, demoralization and failure. Try to prepare for siege warfare on that drive :)
Some type of Loctite is a potential solution to the loose press fit conundrum. Why cant they be "loose" but retained in the bronze end caps. IE not open ended rollers. It the pin rotated in the steel tube is there harm?? Are you going to have sleeves in the hollow drive shaft for the pins to fit into?? I think you alluded to a grub screw. So yes on sleeves. A slight bend or a minor dent in the tubing or pin maybe sufficient retention.
It is fascinating to me to watch someone machine metal. I've never done anything like that. If you don't mind me asking, where did you get your knowledge and training in machining?
@@chucksdesk Nice to hear, I did an engineering apprenticeship from school and then worked in the trade for a couple decades. Now it's just my hobby and I restore classic cars for a living.
Nice machining on the aluminium yoke, but will it be strong enough? I'm not a metallurgist but what about toughness over time? The top yoke in steel looks fine, but the bottom one in ali not so sure.
I was thinking the same, also there seems a lot of parts with potential to fail in the whole shaft, but Ben is far more knowledgeable than me... far more. A naive question Ben..... wouldn't a volvo/car driveshaft be usable?..... strong but heavy. Really enjoy your videos👍✌️🇬🇧
@@timcorso6337 Hi, as long as the stress doesn't exceed 96mpa then fatigue life will be in excess of 500million cycles. I've done the calculations on the aluminium round tube but not on the yoke. Not sure how to do that, probably ought to find out and check it.
@@okgo8315 Hi and yes there are a lot of components that could fail, I've done what calculations I can to satisfy myself on the majority of it but not all. The trouble with using parts like the Volvo driveshaft is that it's designed for a very different application. Max 2000 rpm for a start and torque up to something like 1000lbs/ft. My shaft is under 55lbs/ft of torque and 5500 rpm. The Volvo one wouldn't break but the cv boots wont take the rpm, lubrication could be an issue and it is very heavy. Keeping things as light as possible and reliable is the challenge. It's all in the design and that's why I like this project so much.
@@Ben-Dixey May be get some FE analysis done? If it looks good then may be make the top yoke out of ali as well and save a bit of weight. Thanks for the great videos
@ great suggestion, I know people who would do that for me. What I need to know is the actual torque maximums. I need to measure this on the machine in operation, I would think the torque spikes at no more than 100lbs/ft and normal operation is around 55lbs/ft. It does need to be measured though as guessed torques = guessed FEA
Hi, yes it's a very smooth drive but I believe inefficient. A friend of mine tried it and found that too much power was lost and the oil got hot fast. To keep the oil cool a big oil cooler was needed and a big oil reservoir. It added to much weight. I think there was a gyrocopter trial using a hydraulic motor for pre spin up and that too was abandoned for a more efficient method.
@@Ben-Dixey piston hydraulic motor? I didn't know they were so inefficient. I saw on UA-cam that a team used Rotax912/914 to drive hydraulic motors to make a hydraulic motor multi-rotor. Very interesting. Have you seen it?
@ No I haven't seen it, is it on UA-cam ? A quick Google suggests hydraulic motors are 90-95% efficient, not too bad. Hydraulic pumps are 80-90 % efficient. A synchronous belt drive is 98% efficient so when you take the comparison of pulleys and a belt weight vs the weight of hydraulic motor, hydraulic pump, hoses, reservoir, oil coolers and maybe a fan it doesn't look good. These are figures I just googled so more investigation is needed.
@@grayzhu Thanks, I had seen it I just forgot. 😆 They are using a lot of power to overcome the extra weight and inefficiency. Better than battery's because its powered by a petrol engine but belt drives and collective pitch would probably be my choice rather than hydraulics. It's novel but there are better ways in my opinion.
18:48 how do you get one decimal accuracy on your angle measurements? Seems like it would be difficult to measue one degree, let alone one tenth of a degree. When you measure an angle, do you always measure from the same location?
@@SystemsPlanet Hi, the tool I'm using is a digital inclinometer, it measures down to 0.05 degrees and you can set zero at any point. It's one of the most used tools in my workshop.
@@cloudusterable true. Your comment made me check something, those roller guides will have a centrifugal force trying to pull them off the tube of 140kg. Didn't expect that force to be so great, will have to do some more calculations and testing to make sure they don't come off.
If you wanted to use the Spline as a Hydraulic Ram you'd lube it from both ends and it'd be a Fine Spline If running the CV's under oil pressure is an advantage it's right there ... I think what you've done is going to fail.
@@amrinwello6620 yes, it's around 12lbs/hp of lift providing the blades are made accurate and the drive is low friction. 40hp = 217kg of lift as a rough guide.
@@alfiozaffuto4150 No news at the moment, other than I've bought the wing spar reinforcing tubes and a lathe steady to machine them. Calculations have also been done on the wing strut sizes. I will get back to it but I'm fairly engaged in the helicopter at the moment. The driveshaft has taken longer than anticipated.
Due Respect you have been working BUT ... have you seen what you've done? There's a Lot of Very Breakable Work gone into making something with the same properties as a PTO "Shaft" You can do a CV or not you have now made 8 High Pressure points that are going to need lube and replacing every 20 hours or they will let go the slide shaft will SEIZE leaving you with the controls locked. Where you went very wrong and stepped back on to the SOS [Same Old Shit] is when you lost the rollers and went for a wearable surface a gap making surface a Slap making disaster. You could do Hardened Spline under lube pressure Sum up what you have made is going to fail and worse that the last one which scared the shit out of you ... Correct Lets not go here again, you deviated to rollers then dumped the rollers for something worse ... I want to repeat some of my words "Due Respect" Top Absolute Top of the list "SOS" - remember how "Pharquen scary" that was and you're Going back there? You Should do Hardened Spline under lube pressure You could also adjust that spline movement Using the hydraulic Lube pressure if you wanted that ability. "you have been working BUT ... have you seen what you've done" Due Respect
@@K1VV1939 I understand your concern. I will soon know if it's going to be a problem like you suggest. Initial testing would reveal any backlash that's increasing. It won't get to the point of controls locking up in flight. Spline under hydraulic pressure could work but remember it's also got to be lightweight and simple. Just adding a hydraulic pump is a big decision.
@K1VV1939 With the upmost shiny and due respect... Machining imaginary steel is super easy, believe me, I am extremely experienced! However, sometimes, its quicker to machine actual steel and fill an actual scrap bin with failures. Its super strange but true. My cup of scrap runneth over! But every now and again, I accidently make a good part and deny my scrap bin the pleasure of proving my ineptitude :)
Nice to see you on screen. The alternative scissor arm extenders look promising, if they have enough throw, but torque could be a problem.
Hey!!!!! Happy New Year. Great to see a video. Thank you. Be safe and looking forward to more videos.
@@69dblcab 😊👍 thanks and a happy new year to you!
Your engineering is outstanding. Good to see that. I'm not the only one who uses my videos to go back and see how I did something.👍
@@TSRGarage Thank you! I like your pipe straightening tool, wish I had made one instead of buying one. 😀
Nice video Ben 👍 looking forward to the test. That aluminium drive shaft is pretty slick
@@DktheWelder Cheers DK. 👍
Great new format and explanations. Looking forward to seeing success.
excellent work as usual Ben.. Looking forward to the first test run with new shaft
@@airgunningyup Thank you. I noticed a comment from you on a really early video, you've been watching for a few years. Thanks for the continued support.
In front of the camera FTW.
Great work and explanation
The Dixey Blender will return, looking forward to your next flight, buzzing around the field.
@@lawrenceveinotte 😆👍
Can't wait for next episode.
Great. Thanks for the update. I really enjoy witnessing your amazing Engineering knowledge and skills getting applied to such a fun project. 😊🚁♥
@@Dougie234 Thank you 😊
I'm so glad your back!!!
LOL, Inspector Gadget.. That takes me back, did not expect you to whistle that. Love the format with you in front of the camera. It really does make me feel as though I'm now part of the conversation, almost in your shop.. Great looking engineering.. Kindly Ryn..
I wonder how much of watching inspector gadgets helicopter hat was involved in getting Ben to commit to this project.
@RynCarmichael Really appreciate the feedback. 😊👍
It's been a long time since I watched inspector gadget, I have no idea why that tune came into my head after so long but I hoped it would get noticed. 😆
@@itsnony77 Go Go Gadget helicopter 😆
@@Ben-Dixey I'm glad you did, it made me smile.. Ryn😃
Hey brother Ben,
thanks a lot for letting be the part of your developments , your upgraded new designed drive shaft is really looks trouble free .
lots of little parts and components has been designed and made really well.
as i always tell you i really enjoy to watch the improvements and developments rather then Done it and fly and forget .
nothing late or delayed ,
you are doing what you love to do and we are watching which we love to watch.
will see how this drive shaft will behave , will it need enough lubrication on that new designed expending in and outer tube as well as the bolts moving area where they will go bit up or down in the slits ?
thanks again
@@rajeevshagun7409 Hi and thanks for watching and the lovely comments. 😊
I hope the driveshaft will work but it's a new concept and it's uncertain. If it doesn't then I'll change it for another idea. The bolts will be replaced with rollers and they will be lubricated, there will be no contact between the inner and outer sliding tubes other than through the rollers. The next video will explain it further.
@Ben-Dixey wow ,
Let see the trial of this drive shaft ,
Was previous drive shaft too was hollow inside like tubes (I think it might be )?
Thanks
@@rajeevshagun7409 yes, the previous shaft I made was hollow. As I expect you know the material in the middle of a shaft just adds weight and doesn't give much more strength.
@Ben-Dixey okay ,,
When you said if shaft is not hollow, the middle material don't add the strength but just add extra weight,
Does this rule applies for particular metal or all metals ?
@ All metals, it's to do with the polar moment of inertia. The further away the material is from the centre of rotation the more resistant to twisting it becomes. Like you will see on a vehicle propshaft, the tube driving a vehicle is quite large in diameter and is thin walled tubing. It's lightweight and strong.
Helicopter rotor shafts are tubular for the same reason. The polar moment of inertia is relatively simple to calculate but there are online calculators to tell you which is even easier. It allows you to calculate the strength of a bit of tube and how much stress it's under. Different materials have different limits to stress levels.
brother Ben you look absolutely good presenting front of the camera , this is my first impression about this video , rest i will write in second comment thanks
@@rajeevshagun7409 😊👍
you are a natural on camera, not to worry at all. Tell us again why a splined shaft would not work as a drive shaft ? It would need to be close fitting but that's possible.
@@licencetoswill Hi and thanks, the friction in sliding is the issue with a spline. It needs to be very low friction.
G'day Ben,
Yay Team !
Outstanding stuff, absolutely wonderful...
My recent highpoint was scoring a spare new Battery for the Sting, at $1,010 instead of $2,010..., as an "Xmas Sale Special" ; the Box was sealed at the Factory in Hong Kong in March 2024 & that Sticker has a 16/10 overstamp - my guess is that's when it was shipped (?) ; and it arrived via Contractor (at an extra $190 for the 630 Km...), fully-charged...
So I deduce that the Importer opens the Boxes and maintenance-charges them on the Shelf every month, discounts them about 9 months after manufacture, and probably ships them back if they're unsold a year after leaving the Factory (?).
The Trumpocalypse appears to be unfolding at a very great, and accelerating rate of fulmination...; but Thwaites Glacier's Sea-Ice Tongue broke up the week before last, so maybe the Accelerationists are currently racing to see if they can shut down Industrialisation before Sea-Level Rise beats them, to the execution... ?
Interesting times.
Such is life,
Have a good one.....
Stay safe.
;-p
Ciao !
I like how you describe the control method as like a gyrocopter.
It looks like just a weight shift but it's proper cyclic pitch control.
My RC helicopter using this had the same handling as one with a swashplate.
I hope the new drive shaft works.😀
@@mitubachiflight Hi, yes I do believe a tilting fixed pitch rotor is cyclic control. That's what all the gyrocopter pilots say and I can understand the explanations to why it's the case.
There is one difference though and you might not have noticed on the model you built.
The distance from the pivot point to the top rotor means that the top rotor does more lateral movement than titling. The top rotor can't provide the powered titling like the bottom rotor so it resists and therefore more weight shift is going on.
With small inputs you wouldn't really notice but any large or abrupt input requires significantly more cyclic stick force than a gyrocopter would.
I haven't experienced flying a gyrocopter personally but have had conversations with people who fly both helicopters and gyrocopters and they say there is no force like I describe in a gyro.
If the pivot point was in the centre of the two rotors this force would be reduced.
It's so nice to watch your model flying around, gives hope that the full scale I've built could too.
@@Ben-Dixey Thank you for sharing your fascinating story about the feel of the control stick, which you can only understand by actually holding it.
So my servo motor is fighting against those forces!
My RC helicopters have had many failures. I'm glad it's a model.
I wish you a safe flight.😀
You're getting good in the hover there mate, will done.
@@j6077xxd 👍 I was getting there, hopefully I can fix it and do some more.
@Ben-Dixey good stuff man, your project is fascinating. I should let you know I'm a RNZAF helicopter pilot. When watching I thought these factors might help: Hover on perfectly level ground, the slope causes the downwash to flow downhill which creates a drift which you have to correct. Hover at least 3-5 rotor disc diameters away from those hedges and trees, those obstacles cause the downwash to recirculate on that side which causes a drift towards the obstacle. And the obstacles cause the wind to tumble into your rotor disc generally destabilising you so no nearby surrounds at all is always better. Unsure if you were nose into wind there but that always helps directional stability. The best advice I got learning for hover was "consciously halve your control inputs. So extremely gentle because most of the time we are actually.just correcting our own inputs".
Oh, just saw your other videos, you know more than I do mate, carry on, haha. Waiting for the next episode!
@@j6077xxd wow, I didn't know these effects, thanks so much for sharing the info. I'll see if I can find a better, more level area in the field and also get as far away from hedges and trees as I can.
Nice, more helicopter goodness
You're not going to hear that for me. You have a very good camera presence.
Nice to see more content. Are you putting a cage around the driveshaft in case it fails? Stay safe. Can't wait for the test flight.
Ill second that... Even a simple lightweight ring or two prevent the flail.
@@sky173 Hi and thanks, yes 100% there will be a tube surrounding the driveshaft. 👍
Hey Ben....for the circlip grooves I thought either a woodruff cutter like how you did it, or making a mandrel to go all the way through the U joint to mount in the lathe and grinding up a special tool.
What about a tractor PTO shaft spline for the plunging of the driveshaft?
@@ollied1981 Hi, great idea on turning a mandrel for the lathe, didn't think of doing it that way. 👌
From the static testing I've done splines have too much sliding friction, but I haven't tried a dynamic spline friction test. My feeling is static or dynamic the result would be the same but I could be wrong.
They are usually steel and quite heavy.
You are an artist machist pilot youtuber
Grinding my teeth over the complexity of that shaft... Of my whole design, my driveshaft gives me the most anxiety and its a very simple static transfer compared to yours.
Resonance between the crank and the prop scares the shit out of me, it can snap a crankshaft in seconds.
The math is way above most to calculate with harmonic orders etc.... Way above my head so I put all my effort into aiming for zero lash and hoping for the best (not tested yet)
On the upside, if you hit a bad one it will find any weak spot very quickly, if its not so serious, you ought to be able to see any hammering after your first tests (or it will gain slop that you can feel if you cant see the interfaces)
PS: Fits: Interference fit, slip fit and badgers arse :)
Interesting reading .
@@pimplequeen2 Hi, what are you driving with your driveshaft ?
I've seen a propeller snap a crank shaft due to the lack of a flexible drive coupling between the two.
Resonant vibrations is a concern but until I start testing I won't know. Like you say it will be easy to inspect for any hammering of drive faces. I will keep the backlash to the absolute minimum.
@
Three axis Sub 70kg pusher contraption.
(think I sent you a link to an image way back... Very rustic cable braced fixed wing)
The potential for destructive resonance is always there.
When the boffins attempt to deal with it, they often attempt to hit the first order at low rpm (maybe even sub tick-over rpm) quickly passing through the second order into climb rpm or cruise rpm (Where all the power is) and never reaching another.
Zero lash prevents any hammering we might get form less destructive harmonics.
Apparently, the less destructive resonances can be heard / felt so avoided in standard use... for example, I drive a sprinter van that has a resonance at certain rpm's, I avoid that rpm to prevent the obvious wear (cant be arsed hunting it down and fixing it)
A reasonable analogue for catastrophic resonance is a skidding roller bearing or a bearing that squeal's... They can absorb huge amounts of energy in short order resulting in snapped shafts.
The point is, Its a tad technical for us shed dwellers so we can only really pull the trigger and see what happens.
Any sudden mystery damage (snapped crank, blown prop shaft etc) is likely to be a destructive resonance event and all we can do is change the mass of the crank or propeller or stiffness (amount of spring between the two) to shift its onset.
Stiffer = higher frequency resonance.
@
Just to max out your anxiety :)
Baileys paramotors (four stroke singe) had issues with crank damage.
(I have three of these engines)
I cant find any definitive information on what they thought the issue was...
I "think" they then added flex with rubber washers sandwiching the standard Helix propellers (Removed for the lighter E-props) and stipulate a high tick-over 2600rpm.
Most paramotors use ribbed drive belts instead of toothed belts so if any resonance goes turbo, the belt will have "some" capacity to slip.
Propeller-crank resonance is an issue that is commonly overlooked by us shed dwellers, there isn't much we can do but be aware and try to respond to signs.
Assuming your blades can articulate on the hub, I would exclude their mass from consideration as they are likely to float any high frequency and dampen any low frequency resonance... Just worry about the mass between the hub and crank.
BUT, what do I know, I am a shed dweller with just enough knowledge to be a danger to myself :)
I’m afraid I achieve loose press fits more often than not.
@@rolandsmith2141 😆👍
Hahaha!
I have one sitting on my shelf... Three days machining and one of the bearings drops in with room to spare!
Broke my f88king heart!
Mandrel in lathe for c clips, easy
@@nathanchalecki4842 yeah, didn't think of that. 👍
Dear Ben, great to see you continuing to work on that project. Will you stick to fix pitch tilt head, or switch to a swash plate? If you stick to fix pitch, will you change the pivot point?
Hi, collective pitch would be the right thing to do long term, it maybe possible to implement that and keep the rotor tilting. That would mean I don't need the double swash plates.
The pivot point you mention are you referring to an offset hinge like the benson b9 and gyrocopters ?
@@Ben-Dixey
Its hard to imagine that the complexities of a drive shaft could drive a person to tackle swash plates but having watched some of your vids... I can see why it might :)
@ yeah! 😀 it could have been an easier route. Just discovering another issue to solve with the driveshaft. 🙄
@
I have had such issues force me into incrementally designing two almost different aircraft... New issue on design A throws the advantage back onto design B.
The lack of a definitive solution means chasing our tail... Round and round!
Took me a long time to break out of the deadlock, put the pen down and start actually machining one of the solutions.
It wasn't easy.
Not many actually fire up the lathe risk the bucket of scrap, demoralization and failure.
Try to prepare for siege warfare on that drive :)
You’re not “just talking to yourself” if there’s a camera recording it
😂🙌
Nice work
Some type of Loctite is a potential solution to the loose press fit conundrum.
Why cant they be "loose" but retained in the bronze end caps. IE not open ended rollers. It the pin rotated in the steel tube is there harm?? Are you going to have sleeves in the hollow drive shaft for the pins to fit into?? I think you alluded to a grub screw. So yes on sleeves. A slight bend or a minor dent in the tubing or pin maybe sufficient retention.
Tried that once... lovely tight Loctite fit but lost concentricity :)
It is fascinating to me to watch someone machine metal. I've never done anything like that. If you don't mind me asking, where did you get your knowledge and training in machining?
@@chucksdesk Nice to hear, I did an engineering apprenticeship from school and then worked in the trade for a couple decades. Now it's just my hobby and I restore classic cars for a living.
😂😂 thanks for sharing 👍
Dude is building freaking coaxial helicopter and gets so little views ... What an epic project!
@@SteelCraft99 Thank you for the appreciation. 😊
Nice machining on the aluminium yoke, but will it be strong enough? I'm not a metallurgist but what about toughness over time? The top yoke in steel looks fine, but the bottom one in ali not so sure.
I was thinking the same, also there seems a lot of parts with potential to fail in the whole shaft, but Ben is far more knowledgeable than me... far more.
A naive question Ben..... wouldn't a volvo/car driveshaft be usable?..... strong but heavy. Really enjoy your videos👍✌️🇬🇧
@@timcorso6337 Hi, as long as the stress doesn't exceed 96mpa then fatigue life will be in excess of 500million cycles.
I've done the calculations on the aluminium round tube but not on the yoke. Not sure how to do that, probably ought to find out and check it.
@@okgo8315 Hi and yes there are a lot of components that could fail, I've done what calculations I can to satisfy myself on the majority of it but not all.
The trouble with using parts like the Volvo driveshaft is that it's designed for a very different application. Max 2000 rpm for a start and torque up to something like 1000lbs/ft. My shaft is under 55lbs/ft of torque and 5500 rpm.
The Volvo one wouldn't break but the cv boots wont take the rpm, lubrication could be an issue and it is very heavy.
Keeping things as light as possible and reliable is the challenge. It's all in the design and that's why I like this project so much.
@@Ben-Dixey May be get some FE analysis done? If it looks good then may be make the top yoke out of ali as well and save a bit of weight. Thanks for the great videos
@ great suggestion, I know people who would do that for me. What I need to know is the actual torque maximums. I need to measure this on the machine in operation, I would think the torque spikes at no more than 100lbs/ft and normal operation is around 55lbs/ft. It does need to be measured though as guessed torques = guessed FEA
Let me go off on a tangent.
Have you ever imagined a hydraulic motor drive?
Hi, yes it's a very smooth drive but I believe inefficient. A friend of mine tried it and found that too much power was lost and the oil got hot fast. To keep the oil cool a big oil cooler was needed and a big oil reservoir. It added to much weight.
I think there was a gyrocopter trial using a hydraulic motor for pre spin up and that too was abandoned for a more efficient method.
@@Ben-Dixey piston hydraulic motor? I didn't know they were so inefficient. I saw on UA-cam that a team used Rotax912/914 to drive hydraulic motors to make a hydraulic motor multi-rotor. Very interesting. Have you seen it?
@ No I haven't seen it, is it on UA-cam ?
A quick Google suggests hydraulic motors are 90-95% efficient, not too bad. Hydraulic pumps are 80-90 % efficient.
A synchronous belt drive is 98% efficient so when you take the comparison of pulleys and a belt weight vs the weight of hydraulic motor, hydraulic pump, hoses, reservoir, oil coolers and maybe a fan it doesn't look good. These are figures I just googled so more investigation is needed.
@@Ben-Dixey ua-cam.com/video/Xdp-bZ4FboM/v-deo.htmlsi=HecUBsURjAazKuqF
@@grayzhu Thanks, I had seen it I just forgot. 😆 They are using a lot of power to overcome the extra weight and inefficiency. Better than battery's because its powered by a petrol engine but belt drives and collective pitch would probably be my choice rather than hydraulics. It's novel but there are better ways in my opinion.
There will be no whistling of inspector gadget while in the shop. 😂
@@ZXXpilot 😆👌👍
18:48 how do you get one decimal accuracy on your angle measurements?
Seems like it would be difficult to measue one degree, let alone one tenth of a degree.
When you measure an angle, do you always measure from the same location?
@@SystemsPlanet Hi, the tool I'm using is a digital inclinometer, it measures down to 0.05 degrees and you can set zero at any point. It's one of the most used tools in my workshop.
Aluminium doesn't like load cycling, I'd make both yokes out of steel to be sure 🤔
I prefer narration with video footage of the machine
Side fumbling can be effectively prevented by fitting six hydrocoptic marzelvances to the ambifacient lunar waneshaft.
@@jeremymtc pardon 😆
@Ben-Dixey Having a little bit of a go at typical armchair engineers with some Turboencabulator tech tips 🙂👍
That drive shaft Ben is going at 5,5 k rpm the stresses on it are enormous a car drive shaft goes at quarter engine speed .
@@cloudusterable true. Your comment made me check something, those roller guides will have a centrifugal force trying to pull them off the tube of 140kg. Didn't expect that force to be so great, will have to do some more calculations and testing to make sure they don't come off.
Pleaseplaseplase fillet all slots and holes in the driveshaft, to get rid of any stress concentrators in the zy-plane
@@bakakun Hi could you advise how you mean please ? I understand that sharp edges are stress risers but can't think how to fillet slots and holes?
👍👍👍👍👍👍
👍👍👍👍.
If you wanted to use the Spline as a Hydraulic Ram you'd lube it from both ends and it'd be a Fine Spline
If running the CV's under oil pressure is an advantage it's right there ...
I think what you've done is going to fail.
I want to ask. Can a 40 hp engine power lift a load of 220 kg sir🙏
@@amrinwello6620 yes, it's around 12lbs/hp of lift providing the blades are made accurate and the drive is low friction. 40hp = 217kg of lift as a rough guide.
@Ben-Dixey Thank you sir🙏
Hi. news about grond effect vehicle?
@@alfiozaffuto4150 No news at the moment, other than I've bought the wing spar reinforcing tubes and a lathe steady to machine them. Calculations have also been done on the wing strut sizes.
I will get back to it but I'm fairly engaged in the helicopter at the moment. The driveshaft has taken longer than anticipated.
Have you thought about electric motors? Kills all your drive shaft problems
@@glenn0010 yeah, can't afford it. Maybe one day.
Just don’t be going all Bianca Censori in front of the camera!
😂
@@andrewc755-t6t I think this is the type of comment where the person says the opposite of what they really want. 😆
@@Ben-Dixey ok you’re on. I’ll play ‘happy’ Kanye as long as I can wear a Dickies hoody :-)
@@andrewc755-t6t 😂👍
Due Respect you have been working BUT ... have you seen what you've done?
There's a Lot of Very Breakable Work gone into making something with the same properties as a PTO "Shaft" You can do a CV or not you have now made 8 High Pressure points that are going to need lube and replacing every 20 hours or they will let go the slide shaft will SEIZE leaving you with the controls locked.
Where you went very wrong and stepped back on to the SOS [Same Old Shit] is when you lost the rollers and went for a wearable surface a gap making surface a Slap making disaster.
You could do Hardened Spline under lube pressure
Sum up what you have made is going to fail and worse that the last one which scared the shit out of you ... Correct
Lets not go here again, you deviated to rollers then dumped the rollers for something worse ...
I want to repeat some of my words
"Due Respect" Top Absolute Top of the list
"SOS" - remember how "Pharquen scary" that was and you're Going back there?
You Should do Hardened Spline under lube pressure
You could also adjust that spline movement Using the hydraulic Lube pressure if you wanted that ability.
"you have been working BUT ... have you seen what you've done"
Due Respect
@@K1VV1939 I understand your concern. I will soon know if it's going to be a problem like you suggest. Initial testing would reveal any backlash that's increasing. It won't get to the point of controls locking up in flight.
Spline under hydraulic pressure could work but remember it's also got to be lightweight and simple. Just adding a hydraulic pump is a big decision.
@K1VV1939
With the upmost shiny and due respect...
Machining imaginary steel is super easy, believe me, I am extremely experienced!
However, sometimes, its quicker to machine actual steel and fill an actual scrap bin with failures.
Its super strange but true.
My cup of scrap runneth over!
But every now and again, I accidently make a good part and deny my scrap bin the pleasure of proving my ineptitude :)
muito bom só estou esperando o dia do teste de voo ✈ ✈