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DIY Collective Design: Damper Alternatives?


Alterscape

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I'm building a DIY collective. [edit]Photos here![/edit]I just got all the parts for the collective lever itself together for the first time, and I'm realizing that the motorcycle steering damper I'm using to provide resistance, even on the softest/least-damped setting, provides too much resistance to be comfortable, especially since I need to shorten the lever arm by a few cm (which results in even less mechanical advantage.

 

This steering damper is what I'm using -- it's the same one Slaw recommends as a damper for his RX Vipers, which I am happily using. With no centering system and less mechanical advantage, however, even the softest setting is still too stiff.

 

I assume attempting to modify one of these dampers is how I get hydraulic fluid all over my apartment. Even so, I definitely need something softer than this damper but less soft than "nothing." Any thoughts? Ideally I'd love to buy a similar part that's just softer, but I doubt such a thing exists at the $30USD price point of the damper above. Any input would be appreciated!


Edited by Alterscape
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There's a simpler way to achieve this, but if you don't get the right grease it will never work right. A simple friction joint with a plastic rub in it combined with Nyogel767a provides damping nearly as good as real hydraulic damping, but for a fraction of the hassle because it's a super simple mechanism that is super compact.

 

I shouted from the rooftops about this stuff and linked my friction joints I made with them and it caught VKB's attention. This was the basis of their new 'dry clutches', which also rely on that damping grease. My joints are loaded axially, they load them radially which is more compact and easier to adjust the tension on.

 

Here's an example of a 2 axis gimbals using very simple parts that would can be applied towards any type of mechanism that needs similar damping: https://imgur.com/a/jTw6H

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Maybe your collective head just needs extra weight (steel blocks) if the damper is still too strong. I use the same steering damper in my system using a collective from a Westland Lynx. My collective is quite weighty mind you so on minimum setting I also use neodymium magnets to add extra strength and feel to the damper.

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Thrustmaster Warthog - 47608 with Virpil Mongoose joystick base | MFG Crosswinds - 1241 | Westland Lynx collective with Bodnar X board | Pilot's seat from ZH832 Merlin | JetSeat | Oculus Rift S | Windows 10 | VA |

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Certainly worth a go, mr_mojo97. My collective shaft is an aluminum tube and at this point I don't have any real mass on the end -- it's just a 3d-printed threaded bit that the heads will eventually screw onto, Warthog grip style. The head is likely to be 3d printed plastic so not very heavy.

 

Out of curiosity would you mind measuring your Lynx collective from pivot point to grip? I eyeballed it for my design and I think I'm close but a real number would be great.

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It would be be helpful to know what and how you have interfaced the steering damper, I have made a DIY collective and find that the resistance is pretty close to what I expect and makes for easier flying and that is with a couple of clicks up.

 

Another thing is to keep the shaft clean and I put some petroleum jelly AKA Vas,.. on the shaft which reduces the tendency for binding on small movements.

 

 

I'm using pretty much the full action of the damper so I have some mechanical advantage, next prototype I build will likely have the damper vertical underneath.

 

20 20 hindsight who'd a thunk it. :D

 

Have a look here.

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

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There's a simpler way to achieve this, but if you don't get the right grease it will never work right. A simple friction joint with a plastic rub in it combined with Nyogel767a provides damping nearly as good as real hydraulic damping, but for a fraction of the hassle because it's a super simple mechanism that is super compact.

 

I shouted from the rooftops about this stuff and linked my friction joints I made with them and it caught VKB's attention. This was the basis of their new 'dry clutches', which also rely on that damping grease. My joints are loaded axially, they load them radially which is more compact and easier to adjust the tension on.

 

Here's an example of a 2 axis gimbals using very simple parts that would can be applied towards any type of mechanism that needs similar damping: https://imgur.com/a/jTw6H

 

Now that looks interesting for the cyclic, thanks for sharing. :thumbup:

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

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FragBurn: here's an imgur gallery showing the configuration of the damper. The pivot point is behind and above the axis the collective arm pivots around.

 

Other folks: there's some other description of how the collective is set up in the gallery as well. Reposting here for posterity:

 

"Collective sitting on its side (don't quite have the side-table mount system stable yet -- reference orange clamp!) This is the collective in "down" position, damper fully extended. At about 45 degrees angle, the damper is fully retracted.

 

You can't see from this side, but there is a hall effect rotary sensor attached to the slotted shaft underneath. The sensor's range is ~0.2v - 4.8v, and that's a Teensy 3.0 at right, so the mess of protoboard wiring underneath is an LM324N non-inverting op amp pdip doing impedance matching and level shifting. One of the opamps is configured as a voltage follower tracking the sensor; output of that goes through a resistor divider network to re-scale to ~0.1v-3.3v, and then into a second voltage follower (to match impedance with the Teensy ADC). I'm still getting noise from (I think) noisy 5v USB power, but hopefully I can filter that."

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FragBurn: here's an imgur gallery showing the configuration of the damper. The pivot point is behind and above the axis the collective arm pivots around.

 

Other folks: there's some other description of how the collective is set up in the gallery as well. Reposting here for posterity:

 

"Collective sitting on its side (don't quite have the side-table mount system stable yet -- reference orange clamp!) This is the collective in "down" position, damper fully extended. At about 45 degrees angle, the damper is fully retracted.

 

I don't think you have as much mechanical leverage with the compound lever arrangement would it be possible to arrange the damper to be closer to a line down from the bracket on the collective just as an experiment?

 

The attach point on my collective is about 40mm from the pivot and about 20mm down from the collective shaft. The action is roughly at almost @ 60deg in the down position and to about 90deg in the up position with about 60deg arc of movement in the collective.

 

I have actually angled the collective outward slightly as it's a VR Pit I chose to make it ergonomic after all it always looks spot on right?.

 

Having added the damper I had to adjust to the extra muscle input but that didn't take long also the hand grip which will also become the throttle is about 40mm dia which also helps with the load of the damper. The resistance is about that of an R44 collective.

 

You can't see from this side, but there is a hall effect rotary sensor attached to the slotted shaft underneath. The sensor's range is ~0.2v - 4.8v, and that's a Teensy 3.0 at right, so the mess of protoboard wiring underneath is an LM324N non-inverting op amp pdip doing impedance matching and level shifting. One of the opamps is configured as a voltage follower tracking the sensor; output of that goes through a resistor divider network to re-scale to ~0.1v-3.3v, and then into a second voltage follower (to match impedance with the Teensy ADC). I'm still getting noise from (I think) noisy 5v USB power, but hopefully I can filter that."

 

Nice I need to move away from the pots as well there cheap but only get 200 to 300hrs, maybe try to integrate the control signal a bit as it doesn't need micro second transient response. That might also help with noise although I see the LM324 is decoupled with a tant maybe a 100uF electrolytic on the supply rails could also help. :D

 

What software are you running on the Arduino?

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

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Thanks for the pointer, Thadiun Okona! I understand the "axial" loading based on your photo gallery -- can you say a bit more about the radial configuration?

 

Yep, so with axial the compression is parallel to the shaft, but radially puts it perpendicular to it. VKB machined a hub that has a hinged clamp that puts pressure around the circumference of the circle, an arrangement very similar to a 'band brake'.

 

wZe8bYd.jpg

 

bandbrakemechanismstagesa.gif

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Thank you, FragBurn and Thadiun Okona! Both sets of advice boil down to "I should really buy machine tools" for me. I'm living in a one-bedroom apartment in a big city, so the only fabrication stuff I have easily to hand is a small 3d printer and a portable drill. I think I may just buy some aluminum plate, though, as marking and drilling is so much faster than waiting for the printer to build up a thick plastic plate with tiny holes in it (which is what you're seeing in my photos). It's easier for me to make some holes in plate than to make any sort of precise shapes, so I think I'm going to start with FragBurn's lever positioning advice, while I work on scaring myself up a lathe and a mill!

 

FragBurn, the micro is a Teensy running a really simple sketch that reads the ADC, rescales it, and sends it as a USB game controller output.

 

I'm sampling the ADC at 12 bit resolution and then scaling to a 10-bit value with the range of my actual lever arm, in order to lose as little precision as possible. The hall sensor I'm using has a 180 degree range and I'm only using 45 deg, so that's significant! I thought about using gears to turn the sensor input shaft physically 180 degrees as the arm moved 45 degrees, but again given my lack of precision machining equipment I suspected that would end in backlash and lack of precision. I think I'll end up building one of the DIY hall sensors instead (a Honeywell sensor and some neodymium magnets, as documented elsewhere in the forums) eventually, as that will let me do less level-converting nonsense.

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Thank you, FragBurn and Thadiun Okona! Both sets of advice boil down to "I should really buy machine tools" for me. I'm living in a one-bedroom apartment in a big city, so the only fabrication stuff I have easily to hand is a small 3d printer and a portable drill. I think I may just buy some aluminum plate, though, as marking and drilling is so much faster than waiting for the printer to build up a thick plastic plate with tiny holes in it (which is what you're seeing in my photos). It's easier for me to make some holes in plate than to make any sort of precise shapes, so I think I'm going to start with FragBurn's lever positioning advice, while I work on scaring myself up a lathe and a mill!

 

FragBurn, the micro is a Teensy running a really simple sketch that reads the ADC, rescales it, and sends it as a USB game controller output.

 

I'm sampling the ADC at 12 bit resolution and then scaling to a 10-bit value with the range of my actual lever arm, in order to lose as little precision as possible. The hall sensor I'm using has a 180 degree range and I'm only using 45 deg, so that's significant! I thought about using gears to turn the sensor input shaft physically 180 degrees as the arm moved 45 degrees, but again given my lack of precision machining equipment I suspected that would end in backlash and lack of precision. I think I'll end up building one of the DIY hall sensors instead (a Honeywell sensor and some neodymium magnets, as documented elsewhere in the forums) eventually, as that will let me do less level-converting nonsense.

 

Look into whether there a The Tech Shop in your area, they have everything though you need to take their classes to use the tools but still an incredible resource if you have one nearby. http://www.techshop.ws/locations.html

 

Machining is not something that you can really learn casually by trial and error though, or you won't get very far at least. It's a complicated discipline that req a lot of practice and patience and I highly recommend taking some kind of formal classes (Tech Shop classes are just safety issues and very basic tool use) like at a community college (another good way to get access to machine shop tools/tooling). It's well worth learning.

 

Also, most 'hobby' lathes and mills are kinda junk, though there are exceptions like Grizzly's version of the X3 http://www.grizzly.com/products/Mill-Drill/G0463 (the 'super' version not worth the extra money) or for lathes the popular 10x22 lathe (good) http://www.grizzly.com/products/10-x-22-Benchtop-Metal-Lathe-with-DRO/G0602Z or even better the 11x26 http://www.grizzly.com/products/11-x-26-Bench-Lathe-w-Gearbox/G9972Z

 

Keep in mind that having the tool is only a part of the cost, and by the time you get all your tool holders/cutters/vices/clamp sets/and a million other related bits of tooling costs are adding up and again without actual training these are very complicated tools to run. They also need to be set up right, where they are level and secure and the area can handle the oil/grease/swarf/etc, maching is VERY messy.


Edited by Thadiun Okona
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Thank you! Sadly no TechShop near me (I'm in West Los Angeles, which is basically the armpit of the tool-having-universe, as far as I can tell). Re: home shop stuff, this is all great advice, and thank you! I've taken classes in machining and done equipment fabrication work in undergrad, grad, and for work. I'm not all that skilled since I don't get a lot of practice, but I know enough to know when I need to ask for help at least! In grad school I had free run of a fairly well equipped and maintained Sherline mini mill and lathe, and also a very good welding shop; in undergrad I worked in a theater scene shop which incidentally had a fairly well equipped metal shop attached. I'm not all that skilled, since it isn't my core job function, but I know how to safely make chips and get what I want out of the machines, more or less. Anyhow, a friend with a garage shop does owe me a favor, so if I can figure out what I need to build I may head down to his place some weekend and try to bang out a solution!

 

I mean really the answer is "live-work loft with concrete floors" but girlfriend-approval for that one's a bit tough. ;)

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Although I have only used a drill press and a vice and battery drill and other hand tools for my collective so it's kinda doable. I also used a slide saw but in reality a hand saw would work

 

The 3D print looks awesome so you are definitely on the right track.:thumbup:

 

If nothing else,..

 

A 3 or 4" vice bolted to a chunk of hardwood very useful.

 

A reasonable quality but inexpensive small drill press. An XY vice is really handy but can get away with out one.

 

And I guess you already have a collection of hand tools I think the key thing to remember is we're not putting a man on the moon so for me function wins over absolute precision.

 

Yes I am looking at venturing into programming an AVR or at least maybe one of the preprogrammed units so I can move away from the 3D Pro electronics.

 

@Thadiun Okona some nice toys there. :D

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

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You need to change the geometry of your setup. I use the same damper, the lightest setting is certainly too weak for my collective. Your geometry has a mechanical disadvantage over the damper.

 

Mkz1xek.jpg


Edited by Deezle

Intel 9600K@4.9GHz, Asus Z390, 32GB DDR4, EVGA RTX 3070, Custom Water Cooling, 970 EVO 1TB NVMe

34" UltraWide 3440x1440 Curved Monitor, 21" Touch Screen MFD monitor, TIR5

My Pit Build, VKB Gunfighter Pro w/WH Grip, TMWH Throttle, MFG Crosswinds W/Combat Pedals, Cougar MFDs, Custom A-10C panels, Custom Helo Collective, SimShaker with Transducer

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Thanks for sharing the pic, Deezle!

 

A couple of questions: How long is your collective 'lever arm?" (ie, the distance to the point where you grab from the pivot)

What is the angular range of the collective?

 

I set mine up to go from level to about 45 degrees. I think I could maintain that by moving the mount point down low as in your setup -- will give it a go when I return from travel and see where I end up.

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There's a simpler way to achieve this, but if you don't get the right grease it will never work right. A simple friction joint with a plastic rub in it combined with Nyogel767a provides damping nearly as good as real hydraulic damping, but for a fraction of the hassle because it's a super simple mechanism that is super compact.

 

I shouted from the rooftops about this stuff and linked my friction joints I made with them and it caught VKB's attention. This was the basis of their new 'dry clutches', which also rely on that damping grease. My joints are loaded axially, they load them radially which is more compact and easier to adjust the tension on.

 

Here's an example of a 2 axis gimbals using very simple parts that would can be applied towards any type of mechanism that needs similar damping: https://imgur.com/a/jTw6H

 

Odd, UIV (from VKB) told me there is no need for grease...so I think you may have your facts a little jumbled?

VR Cockpit (link):

Custom Throttletek F/A-18C Throttle w/ Hall Sensors + Otto switches | Slaw Device RX Viper Pedals w/ Damper | VPC T-50 Base + 15cm Black Sahaj Extension + TM Hornet or Warthog Grip | Super Warthog Wheel Stand Pro | Steelcase Leap V2 + JetSeat SE

 

VR Rig:

Pimax 5K+ | ASUS ROG Strix 1080Ti | Intel i7-9700K | Gigabyte Z390 Aorus Master | Corsair H115i RGB Platinum | 32GB Corsair Vengeance Pro RGB 3200 | Dell U3415W Curved 3440x1440

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Odd, UIV (from VKB) told me there is no need for grease...so I think you may have your facts a little jumbled?

 

It's possible it doesn't use any (they do call them 'dry' clutches after all), but the evolution of the upgrade started with it as far as I know and branched from there. So far I've found the grease works better than any combination of dry materials I've tried (felt, numerous combos of plastics and metals), but there could always be some magic combination or implementation that does it well or well enough in this application which might be the case here, though when I was using it for primary controls as a means of damping zero-order aim there was no contest and the differences remarkable.

 

Even if they work ok dry, with damping grease and lower clamp pressures I have little doubt the actual performance of the parts as dampers would be better, but this is likely to remain conjecture for a long time as I don't have one here to do any comparative testing with.

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It's possible it doesn't use any (they do call them 'dry' clutches after all), but the evolution of the upgrade started with it as far as I know and branched from there. So far I've found the grease works better than any combination of dry materials I've tried (felt, numerous combos of plastics and metals), but there could always be some magic combination or implementation that does it well or well enough in this application which might be the case here, though when I was using it for primary controls as a means of damping zero-order aim there was no contest and the differences remarkable.

 

Even if they work ok dry, with damping grease and lower clamp pressures I have little doubt the actual performance of the parts as dampers would be better, but this is likely to remain conjecture for a long time as I don't have one here to do any comparative testing with.

 

 

 

Roger that. I have a tube of 767a on hand in the case that I chose to go the VKB route and your testing ever shows it is indeed improved with the use of damping grease.

 

Appreciate the response!

 

 

Sent from my iPhone using Tapatalk

VR Cockpit (link):

Custom Throttletek F/A-18C Throttle w/ Hall Sensors + Otto switches | Slaw Device RX Viper Pedals w/ Damper | VPC T-50 Base + 15cm Black Sahaj Extension + TM Hornet or Warthog Grip | Super Warthog Wheel Stand Pro | Steelcase Leap V2 + JetSeat SE

 

VR Rig:

Pimax 5K+ | ASUS ROG Strix 1080Ti | Intel i7-9700K | Gigabyte Z390 Aorus Master | Corsair H115i RGB Platinum | 32GB Corsair Vengeance Pro RGB 3200 | Dell U3415W Curved 3440x1440

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Thanks for sharing the pic, Deezle!

 

A couple of questions: How long is your collective 'lever arm?" (ie, the distance to the point where you grab from the pivot)

What is the angular range of the collective?

 

I set mine up to go from level to about 45 degrees. I think I could maintain that by moving the mount point down low as in your setup -- will give it a go when I return from travel and see where I end up.

I keep forgetting to measure it when I'm home but I wanna say somewhere around 20"/51cm. Angular range is somewhere in the 35º range probably.

Intel 9600K@4.9GHz, Asus Z390, 32GB DDR4, EVGA RTX 3070, Custom Water Cooling, 970 EVO 1TB NVMe

34" UltraWide 3440x1440 Curved Monitor, 21" Touch Screen MFD monitor, TIR5

My Pit Build, VKB Gunfighter Pro w/WH Grip, TMWH Throttle, MFG Crosswinds W/Combat Pedals, Cougar MFDs, Custom A-10C panels, Custom Helo Collective, SimShaker with Transducer

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