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gear motors vs scn5

Discussion in 'New users start here - FAQ' started by Donerb, Mar 5, 2018.

  1. PiaMan

    PiaMan Active Member

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    My Motion Simulator:
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    nothing that moves has zero backlash but i don't have anything capable of measuring the SCN backlash accurately. Just so no one thinks I am saying that :)

    My SCN rig is pretty much neutral balanced though. and yes 3x150mm

    Agree with all your points @noorbeast except the cage of budgies part lol, however I still completely respect your opinion on the matter:)

    I didnt comment on diy actuators because i have no first hand experience. I could guess they would be comparable to scn or better based on what you use for components. I just wanted to add my thoughts based on first hand experience. And I feel that there are lots of advantages to DC motors but the "cage of demented budgies" and "99% of people would choose" type of comments are not accurate (in my opinion) and shouldn't sway someone towards one system or another. I know a few users found them loud and everyone has there own limits however of at least 25 people who have been on my rigs and raced against me not even one person has commented that either rig was loud. If you race with headphones and hope that someone can sleep in a bed in the same room as you I think either system will be too loud. In my house I can hear the DC one upstairs clacking but not the SCN until i get halfway down the stairs.

    Im not defensive of my purchase as Ive said that I would probably choose a DC rig if i started again. I'm just presenting an honest first hand account of the pros and cons I have found to try to contribute to the community and help others make the choice that is right for them.

    I'm still unconvinced even with design considerations that MY worm gears would match the SCN or other ballscrew mechanism in terms of fine detail. That is not to say they cannot produce fine detail, just not as fine specifically in the heave axis. (i'm only talking racing here. I have minimal experience doing anything else on my rigs).

    And a final point. I have at least 100x hours on my DC rig ~tuning~ as on my SCN. My SCN system just felt great with a few minor tweaks. I have spent countless hours running and rerunning and testing new Tuning Centre values, replaced rod connectors, tried dampening the arms themselves, made new lighter arms, changing the weighting, changing the seat on the DC rig to overcome the missing sensations and clacking. With my backlash values its not possible except, which i am guessing from watching others' DC videos, by increasing that heave movement which doesn't feel good to me. I see the amount of head shake going on and yes i can make my DC rig feel/look like that. Just the cars I drive don't feel like that in real life so i don't want them to on my rig.

    And i totally agree about tricking the mind. The quick and precise movements of the scn trick my mind better. This is subjective so i provided measurements to back up my observations.


    Curious @noorbeast for comparison, how much backlash on your motors? Is it something you are able to measure? Nick never answered and I am curious if mine are the normal sort of range.


    best wishes all
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  2. Gadget999

    Gadget999 Well-Known Member

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    i use wheel chair motors and gearbox

    no sound - no backlash
    also very powerful
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  3. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
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    This is the actual backlash of my rig:


    An this is the actual POV fine detail of my 3DOF compact sim, with motion dialed down to 93% because it was a bit much above that, if you watch my head my own body mass results in even greater movement than the rig itself:
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  4. PiaMan

    PiaMan Active Member

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    Thanks noorbeast. looks similar to my dc rig id say.

    I can hear the clunk same as mine when you test the backlash just with fingers. I feel that a fair amount of movement occurs in that little wiggle room. Or better worded, i prefer that alot of movement occurs in that wiggle room as opposed to pushing past it.

    Im sure i could reduce the clacking by rubber mounting the motors to prevent the transfer through the steel of the rest of the rig. But more likely the motors will get repurposed to the motorcycle rig i want to build.

    Cheers
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  5. Nick Moxley

    Nick Moxley Well-Known Member

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    So where's these super loud clacking videos of gear motors ?

    i cant seem to find them.....Yet when i find an Actuator vid with no game audio in the background all i hear is Demented budgies singing their song.......strange how that is eh. :confused:
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  6. RandomCoder

    RandomCoder Active Member Gold Contributor

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    It seems to me that you are searching for an arguement as @PiaMan has already pointed out that recording devices are more likely to pickup and amplify high pitched sounds than lower frequency tones. Each to their own, I think the war of words should stop now, it's not really consturctive anymore.
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  7. Gadget999

    Gadget999 Well-Known Member

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    My Motion Simulator:
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    you can see a vid of my sim here - no noise or backlash



    the bangs in the background are somebody working (and a dog barking !)
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    Last edited: Mar 8, 2018
  8. PiaMan

    PiaMan Active Member

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    Fantastic looking rig :)

    No noticible heave so i dont think this video is a good representation. Espescially in the video when driver goes off road. If that works for you awesome. Its not the motion i want for my rig.
  9. PiaMan

    PiaMan Active Member

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    Here you are @Nick Moxley ... Even with game sound. But no matter what there is a hard clacking clearly audible. Still waiting for your backlash data measurements.
    Also this audio was shot with just onboard mic since the audio wasn't useable except directly output from the game

    YES - there are things that have been improved since this video. This video is not about what can be changed in tuning or otherwise as its over a year old and lots of changes have occurred. It is to show the clacking. Currently the rig has a flight stick on it so I can't shoot a current one nor do I want to debate this anymore.

    Both systems have sound as clearly demonstrated by collectible data. DC motors have backlash as measured with quantifiable measurements. This backlash causes: 1. loss of fidelity and 2. Noise

    A good debate is how much these factors affect performance. When someone says the factors do not exist they are refusing to acknowledge facts.

    @Nick Moxley won't ever soften his opinion and thats ok. I respect that his system is perfect for him.
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  10. joe extraknow

    joe extraknow Member Gold Contributor

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    Just let you know SCN5 backlash is 0.3mm and repeatability is +/-0.1 mm that is how high resolution for the SCN5 actuator, per spec.
    I tried both solutions, in comparison,day-and-night difference in terms of resolution and detail. I will never go back gear motors for racing simulator, period!
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  11. Gadget999

    Gadget999 Well-Known Member

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    That is the first time we had the rig running with the wheel in the rig

    Effects turned down to 15%

    Only sway and roll enabled iirc

    You can't have real heave on a 2dof but simtools does simulate it - its a bit violent for my lad
  12. Nick Moxley

    Nick Moxley Well-Known Member

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    :confused::thinkwhen was the last time you changed your rod ends, Or what Spec are those. That doesn't sound like the motor's At all. Sounds Exactly like when i had a rod end going bad. Replaced, And BAM Back to near silence.

    there's Zero Metal to metal in the motor itself. It goes D shaped Steel Motor shaft into Nylon Flex Bushing, into Steel Worm gear, which works a Nylon Main Drive gear.

    Swap out them rod ends with some Fancy Greased Rose Joints and i bet 98% of your noise disappears.

    In regards to my backlash, Not sure, they wiggle a good bit, But i would venture to say its more than what you posted, ive ran the crap out of my motor's most of their life, Im shocked there still kicking to this day. (Yes I have replaced the main bushings with upgrades from Motion Dynamincs) And to be honest, I might have even swapped the gear over 180 at some point as we only really run on less than half the gear, So flipping 180 a few years ago gave me new teeth on the worm gear to play with.

    I dont have many new vid's, but there's more than a few and you can barely hear the motor's despite varying game volumes, You can also hear me banging on the pedals/Shifter, But next to no motion noises. And the bobble hat obviously confirms my heave is On Point unlike other setups with a wee lacking in the PID/Tuning center.
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  13. PiaMan

    PiaMan Active Member

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    Appreciate the suggestions :)

    I bought the ones you suggested and have on your rig since this video. Ive had someone drive and held each part. Its the motors. Maybe poor manufacturing, who knows. I did not open the motors to see but it sure sounds like metal on metal. Could be exaggerated because you have aluminum which doesnt ping nearly as much as the steel rig i have.

    What is it that clunks when you feel backlash with your fingers as per noorbeasts video?

    Seems if it was just plastic, moving it with your fingers should not make an audible clunk.

    If youve been in your motors you certainly know much more than i on how there work

    For backlash if you have the same i still argue the fidelity. Think if you have 2mm of backlash and the motion calls for one in each direction, say for engine vibrations, you would essentially feel nothing as the gear would be just tapping either side if the backlash. You have to come past that backlash before you feel the motion.

    Like i said you can compensate by tuning so the 1mm is 1.5mm or something until you feel it

    Thats my non engineer conclusion and i just cant see any other way. If im missing something let me know.

    Cheers
  14. SeatTime

    SeatTime Well-Known Member

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    The standard 25:1 gearboxes normally have a plastic main gear and coupling. - @Noorbeasts gearboxes are upgraded metal ones, due to them being around 50:1. I had both in my first sim (metal 50:1 in my heave setup). The plastic gear ones are noticeably quieter.
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  15. PiaMan

    PiaMan Active Member

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    This may be the root cause in the difference of opinion about noise. I did not open mine but just wiggled the backlash some more. I just can't see plastic making the amount of sound mine do from 2mm of movement with my fingers.

    Maybe pgsaw got some with metal gears? Mine for sure have 25:1 written with fine point sharpie on the motor casing but there is nothing saying I didn't actually get 50:1. I wouldn't know the difference since I only have the one set of motors.

    Pgsaw does sell these for sawmills so maybe the plastic was stripping out under heavier load and his supplier changed out that part.
  16. PiaMan

    PiaMan Active Member

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    That actually solidifies my point. Heave should not be so violent but with gear motors it has to be to pushed past the backlash causing it to be more aggressive than it should be especially for road cars.
  17. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    If you can move the gearboxes easily by hand then they are 25:1s, 50:1s can be back driven but not by hand.

    I use 60:1s and they are metal gears. But I have previously use 25:1s and there is not that much difference, most noise comes from elsewhere on the rig.

    The main sources of sound on my rig are from the heave knee when driven hard (the designers never envisioned this type of use and abuse), but most sound is from the big buttkicker when it is over driven.
  18. Nick Moxley

    Nick Moxley Well-Known Member

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    Incorrect, I get plenty of soft rolling "humps and bumps" outta my heave axis on a Softer suspension street/Factory/Production cars.
  19. PiaMan

    PiaMan Active Member

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    So iracing is in between seasons and i thought id fire up assetto corsa and it made me think of you @Nick Moxley

    I just tossed my phone on my steering platform so you can hear what scn actually sounds like in cockpit playing a game.

    Between the turbo blow off and the tires the scn is not audible at all. This is at my normal game volume.
  20. SeatTime

    SeatTime Well-Known Member

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    Well, I don't own a set of SCNs, so you could show me anything and I would have to believe it, but some members in the past have gone to allot of trouble trying to quiet them down, so ... Maybe you have the stealth model, are they mat black - can they not be seen on radar ?- sorry:oops:, this 'debate' has gone on for a while, so I'm just seeing the funny side now :p. All that really matters is that your happy with them :thumbs.
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