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Drew Wars: A New Suspension Dream

Discussion in 'FMA' started by Drew, Jan 14, 2018.

  1. Drew

    Drew FRP H-Bar

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    Yup, it's happening! Again.......... I'm sure there's plenty of you getting sick of me posting right? RIGHT?!

    Anyway, focus in this will be proving the even FM/FMA with their different gear cover will not stop me from making a suspension build, although I kind of proved it with the AR already.
    Using the same suspension method, I've also worked out how to implement steering :D (I hear you all thinking "oh good god, here he goes again!").

    I've been thinking of what I want on this build. The suspension is a given, the steering now that I've worked it out will also go on, this means I'll need to use a sliding damper for the front, so simple and nothing too fancy I guess.
    At the rear I'm thinking a sliding damper like the front, don't think I'll do anything crazy there. I was thinking of making a variable brake system which will also allow me to attach the body damper. I'm also going to add a one way wheel set with axle piercing mod. Hopefully it all works out.

    I've got the rough idea in my head, I've also started prototyping a the brake system and I've already built the prototype suspension upright. A couple photos.


    The upright:

    Since it's pretty much impractical to do a wishbone system (impossible within tamiya specs), I got to thinking (Finkle and Einhorn, Einhorn and Finkle, Finkle and....Einhorn....Finkle is Einhorn!! OH GOOD GOD!), using the same method as the AR won't work, I can't make the two different axis using only the plastic steering control. So how to separate the two. Then I turned to my MS Fissv2. That's when it hit me, I can't have two mounting points on the upright, only a single mounting point for the pivot. I came up with this below, I took two hex standoffs, drilled a 2mm hole in each (not all the way through), worked out the positioning with a shaftstopper between them, after that I from the spine to spine on the standoff and trimmed down an MS gear shaft to fit snug between the two. Then it was just a matter of assembling it in a near identical process to the MS upright.

    The end result is this.
    IMG_20180114_171457.jpg

    I've tried it next to a spare chassis and it's exactly what was needed. Again, this one is customised to the FMA, so If building this for another car, would need to start from scratch and modify it accordingly.


    The Variable Brake:

    Still a work in progress, was thinking of a couple ways, the first being like the FL system but add a spring to each chassis mount but I figured using two springs would maybe make it too hard and also allow it to flex favouring a specific side rather than keeping it level.
    So after going through a whole bunch of images, I found a damper setup I liked and figured I could probably rig it to the brake and have the brake and dampers integrated.

    So I've started work on this.
    IMG_20180114_171418.jpg

    The shaft stopper currently mounted will be attached to the chassis through some form of mounting I'll think about later, but will probably be the same method as the silver FL system from my previous FMA build.
    Attaching the other end to the brake with another shaft stopper, this should allow the brake to move unimpeded yet keep it level. The dampers will attach directly to somewhere on the brake most likely.

    The good thing with how this is mounted, I'll also be able to mount the body damper to the same shaft stopper, both will operate smoothly and neither will impede the other.

    Hopefully this will turn out as good as if not better than the AR build.
     
  2. warwick

    warwick Washer

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    Nah bro, its inspirational.

    I think UK dead scene done good for your creativity.
    If there's race over there, you probably more focused on tuning in your racer setup rather than exploring your ideas.

    Keep up the good work
     
    Drew likes this.
  3. Drew

    Drew FRP H-Bar

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    I've been doing a little work on this, I've finally worked out how to stabilise the gears on my fma.
    I've made the front uprights for the steering and suspension, also done the rear tail and front under plate. I want to get a pack of 13/19 carbon popsicle when I got the money, so the stays will take a while.
    I've also started working on the suspension posts braces. Here's a few photos.

    IMG_20180123_181518.jpg IMG_20180123_181619.jpg IMG_20180123_181754.jpg IMG_20180123_234139.jpg

    Need to trim and start tweaking, the rear (top image) needs to trim the underside of the braces so I can make the guide/support bar while the front posts need trimming back a little for two reasons, first is to allow the shaft stopper to fit and second to align the shaft stopper closer to the correct position for the push rod :

    IMG_20180123_234205.jpg IMG_20180123_234305.jpg

    Welp, that's all for now. Oh, and I sent the AR suspension on a road trip to Indonesia for Rangga at team flash to check out and review, just hope it don't get lost in transit.
     
  4. Drew

    Drew FRP H-Bar

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    Been doing a bit more. Worked on the rear end and the front uprights.


    This is the rear, I've trimmed the support spars/braces, I've mounted a shaft shaft stopper which will hold the body damper and rear brake control. Also mounted the upright mounts to the chassis. Will need to lower the tail a little later once I've got the rear suspension and wheels/tires done. Need new drill bits to prepare more axles, so I've just put the old axle back and kept all the gears in place at the rear.
    IMG_20180124_200028.jpg IMG_20180124_200116.jpg

    The front has been a whole different bundle of fun....
    I've had to remake the right side upright because I forgot there was a difference in mounting point on each side. I've had to make the right side a bit longer. But I've been able to mount it without interfering with the motor too much. Just a slight nick.

    IMG_20180124_200310.jpg IMG_20180124_200509.jpg

    Anyway, both uprights are mounted and front end is looking good. Still got to do the front spars/braces and posts.
    Still so much more to do.
    IMG_20180124_200149.jpg IMG_20180124_200205.jpg IMG_20180124_200223.jpg
     
  5. Drew

    Drew FRP H-Bar

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    Been working on the front, got the posts and spars/braces trimmed. Also mounted the ball link and trimmed a little nuck in the uprights for where the wheels hit when turning. Don't know what I'm going to do about a shell right now though >.<;

    IMG_20180125_191954.jpg IMG_20180125_191836.jpg

    I've also been working on the body damper mount / brake support. Still not sure how I'm going to finish it up yet, but here's a first look at what I'm upto. Had to come up with someway of attaching a body damper that wouldn't interfere with the suspension, this was pretty much the only thing I could think of without growing it too high. Also, not sure what to do about a return mechanism for the rear brake assembly, was thinking a couple small dampers would work or maybe try to incorporate something spring loaded.

    IMG_20180125_191620.jpg IMG_20180125_191743.jpg

    I think I got the front uprights mounted ok since I can thread an axle through both chassis and uprights.
    Oh, and I've already finished preparing the the one way wheel set with piercing mod and tamiya low profile offset tread tires, just need to give them a little trim to get those little rubber nubs off.

    IMG_20180125_192142.jpg
     
  6. Drew

    Drew FRP H-Bar

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    Me again, getting towards the end of what I can do right now, still waiting on new 1.2mm bits and carbon roller popsicles. I might be able to do a little work on the shocks tomorrow or when ever I feel like it.

    Today however, I readjusted the rear brake assembly to be a little lower, trimmed down the popsicles for the tail support and body damper. Also add the side plates to the body damper, but it feels a little too wide right now, I'll dive into that a bit more later, so first, more images!

    IMG_20180126_163330.jpg IMG_20180126_163447.jpg IMG_20180126_163415.jpg

    Probably need to look into doing something to stop the body damper going so far.
    The weights on the back are just for testing right now, but is what I'll probably go with at the end.
    As you can see, I've reeeeeeeally trimmed down the popsicles.
    You'll also notice, with the brake design like this, it's able to keep all wheels on the ground through all slopes/jumps....hopefully.

    A bit of a closer look at the brake through different inclines:

    IMG_20180126_163625.jpg IMG_20180126_163635.jpg IMG_20180126_163640.jpg

    If there were brake sponge on there, you'd notice that the greater the incline, the more brake pressure is applied. Hopefully this will allow for plenty of versatility when setting up brakes depending on track, keeping in mind that this suspension method will also have the tires acting a touch as brakes when the suspension is working.

    And finally, the conundrum I have with the body damper:

    IMG_20180126_164209.jpg

    At the moment it's sitting at 91mm wide (compare with rear wheels I set to roughly correct width once finished), I think it's a bit too wide but question is, where do I want the weight positioned?
    If close to the wheels, it needs to be roughly this wide to avoid interfering with the uprights while being able to push the weights as for forward as possible. On the other hand I could have the weights sit behind the uprights and closer to the chassis so width wouldn't be a problem, but then the weight will be set closer to the middle, causing more weight to be displaced towards the rear.

    Suggestions?
     
  7. Drew

    Drew FRP H-Bar

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    Final post for the time being, still waiting on new 1.2mm bits and stays for sliding damper.
    I've finished up all I can with the chassis for now. Still need to work out what to do about a shell.

    Anyway, I'll start with the body damper assembly which I've finalised. I mounted a shaft stopper on top of the rear gear cover. I filled down the screw head on the inside to avoid contact with the axle.

    IMG_20180127_163854.jpg IMG_20180127_163917.jpg


    I prepared the parts needed, the body damper, the rear brake support and other bits.
    Needed two bearing washes, the roller insert with lip trimmed down to frp thickness, a screw and lock nut.

    IMG_20180127_163936.jpg IMG_20180127_163948.jpg

    Assembly is pretty easy, screw with bearing washer, damper frp, roller insert, rear brake frp, gear cover/shaft stopper and repeat on the other side.

    IMG_20180127_164103.jpg IMG_20180127_164203.jpg

    On the brake support end just attach another couple of bearing washes and the shaft stopper.

    IMG_20180127_164445.jpg IMG_20180127_164713.jpg IMG_20180127_164726.jpg

    And that's done. It's easy to remove, just needs a single screw attaching the rear shaft stopper to the brake plate, the gear cover will just clip into place. The rear support will help keep the gear cover in position and keep the body damper straight.

    I've also finished setting up the suspension. On the front I used a pair of ball links and on the rear was the same orange clip method from the AR build. I also added a stabiliser disk to act as a damper stopper to prevent the damper going vertical and uncliping the gear cover.

    Rear end:

    IMG_20180127_190411.jpg IMG_20180127_190421.jpg

    The body damper is clear and doesn't interfere with the rear suspension in any way.

    IMG_20180127_190445.jpg


    Front end, not clipped on yet because I've got an axle in keeping the uprights in correct position while thread-lock cures on the mount screw.:

    IMG_20180127_190522.jpg IMG_20180127_190613.jpg

    Overall I think it's looking good, but I won't know until I can get the axles finished and wheels attached. Anyway, here's the whole thing:

    IMG_20180127_192816.jpg
     
  8. Drew

    Drew FRP H-Bar

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    I had a spare shell, I suck at doing anything with polycarb shells, but here's what it looks like and what it will finish looking like once the axles/gears are finished (wheels not actually attached).

    IMG_20180129_132120.jpg IMG_20180129_132158.jpg

    Edit:

    After letting the glue set, I tried to test the suspension, but unfortunately, it wasn't strong enough and the uprights started pitching (blue arrow), so I needed to further stabilise the upright, I decided I will do this by gluing some frp where the orange box is and adding a second shaft stopper. Will update once done.
    IMG_20180124_200223.jpg
     
    Last edited: Jan 29, 2018
  9. Drew

    Drew FRP H-Bar

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    So I've just finished rebuilding the front uprights and chassis mounts. Here's the updated version:

    IMG_20180130_173303.jpg

    Note the difference between left and right, this is due to the gear cover latch on the left and the motor cap on the right side.

    Here's the end setup:
    Left side -

    IMG_20180130_221748.jpg IMG_20180130_221803.jpg

    Right side -

    IMG_20180130_221711.jpg IMG_20180130_221725.jpg




    And finally the working example pics:

    IMG_20180130_221610.jpg IMG_20180130_221645.jpg IMG_20180130_221252.jpg IMG_20180130_221314.jpg IMG_20180130_221324.jpg IMG_20180130_221428.jpg
     
  10. Drew

    Drew FRP H-Bar

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    So I've just finished the basic build (excluding the sliding dampers) to test how it's working.
    Here's a short demo:


    Is it possible to have full independent suspension on a single shaft motor car? Yes, I proved that with the AR.
    Can you add steering to it also? Yes, but I'm going to need to work out how to tidy it up.

    What I've come to find is that the wire loop method I used to connect the wheel axles, like with the AR, isn't working as well for this build. I think one reason is probably the wheel weight and the one way wheels (including untrimmed tires which are heavy) is causing some wheel instability. But I think the second reason is far more important, the wire loop is just not working on the front due to either the axles not being long enough or the loop just can't handle the different twists.

    Let me show why I think the one way wheels are causing some instability.
    I've tried to do the piercing mod I found, but there's two methods to this, first is this:
    IMG_20180203_170624.jpg

    The second is through and through, by removing the center pin that slots into the top of the big pinion:

    IMG_20180203_170633.jpg

    What you need is this, the big pinion needs to sit flush and not move, the single pierce can help with this, by not piercing the wheel face plate, the axle can push up to the plastic pin to help keep the big pinion flush and prevent the big pinion moving up and down:

    IMG_20180203_170704.jpg

    If you don't do the pierce mod you end up with the big pinion will be able to move up and down, unfortunately, by doing the through and through mod, you end up causing the same problem you try to eliminate by doing the pierce mod. This causes the wheel to move in and out by about 1mm when attached to the car.

    IMG_20180203_170656.jpg

    In short, only pierce the big gear if you want to stabilise the one way wheel set.



    Now as to the axle connection method, I've been thinking of probably changing it.
    I'm thinking of doing the cup and ball universal joint method:

    IMG_20180203_165525.jpg IMG_20180203_165559.jpg

    Just using the double end for example. The actual method would be to have the cup on the gear axle like with my previous MS suspension build. But the wheel axle will have the ball end, only on a single end.

    Because the current build uses the wheels to wheels to keep the upright attached to the chassis, this method won't work unless I fix the uprights directly to the chassis, like the front uprights currently are. This would mean I have to change the rear mounts.
    To this end, I'm thinking of using the uprights from the MS build (which I already took apart to prepare for another method), so these might look familiar to some people:

    IMG_20180203_165642.jpg IMG_20180203_165710.jpg

    I would need to find some way of mounting the assembly to the chassis. What I'm thinking right now is to make some frp that can sit flush at the side of the upright assembly and glued to the chassis.

    IMG_20180203_165915.jpg IMG_20180203_165921.jpg

    By adding some layered frp to the chassis indicated by the red boxes, I can make a drill hole through and mount the upright with a couple screws which will allow for removing the upright for maintenance.
    So, although I kind of got close to finishing the build, I really want to take the alternative option.
    I'll need to cut new axles and make the cup and ball joints. Looks like this is going to take a little while longer.
    Welp, that's all for this update.
     
  11. Drew

    Drew FRP H-Bar

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    Done a bit more on the transmission.
    I've changed it from the wire loop link to a single ball/cup joint on all wheels.
    Take a look at what's been done:

    The axle prep:
    Made some new cups from 6mm alu spacer. Just used the wheel axle from earlier in the thread and put a pin made from motor spring through the wire loop hole then used a bit of solder before shaping.
    IMG_20180204_155940.jpg

    Rear uprights:
    So I layered 6 or 7 frp popsicles, glued them together and also added a screw to help prevent them from coming apart at any of the glued seems. I then drilled holes from the side to allow me to use 2x short screws at the top to hold the wheel frp in place and a 30mm screw to hold the bottom wheel frp.
    IMG_20180204_175454.jpg IMG_20180204_175654.jpg

    Axles:
    Assembled the axles with gears then used some thread lock to attach the cups to either end. I like to build up the thread lock around the outside so that it can seep in to where it needs to be, after letting it dry, I'll wipe off some of the wet excess. The bearing spacers act as a glue shield. This is what gave me the strongest attachment method when making the MS previously.
    Axles are rotating beautifully with no resistance.
    IMG_20180204_213031.jpg

    Wheels:
    I've finished up for now by attaching the rear uprights using glue to the chassis side using the ball/cup as the center point.
    I reattached the front wheels also. Once all the glue and thread lock has dried/cured, I'll remove the wheels one last time to set the wheel axle to correct length so that it's neither too tight or too loose on the ball/cup and also to apply some grease.
    I think the overall wheel base width is about 96mm....not sure if that's ok for tamiya reg, some one will have to let me know.
    IMG_20180205_170114.jpg IMG_20180205_170244.jpg IMG_20180205_170332.jpg

    Kino:
    Finally I'll end by giving Kino a bath while waiting for things to dry (she loves her bath time).
    Yes Kino, I know it's bath time....I'm coming.....
    IMG_20180205_170342.jpg


    Edit:
    Put it back together, gave a test.....she sounds nice.
    Front wheelbase width = 96.5mm
    Rear wheelbase width = 97.5mm
     
    Last edited: Feb 5, 2018
  12. Drew

    Drew FRP H-Bar

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    Just a quickie for new 5min video of the new setup using a single universal ball/cup joint instead of the previous wire loop method.

     
  13. Drew

    Drew FRP H-Bar

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    Finally finished the build, although there are some little issues.

    I've only added plastic rollers for now, since this was just a 'build it to see if it can' project.

    Both front/rear stays need replacing, using old, broken carbon 13/19 stays.

    I've over trimmed the rear left bearing mount on the chassis, so the whole axle can slip to the right, due to the drive train method though, the axle will still maintain traction on the rear wheels however.

    Another issue is that I feel as though the rear wheel base is a little too wide. The left suspension also has some resistance which maybe an issue with the cup/ball joint.

    Other than that, it's working, suspension is working, body damper is working, tail damper/variable brake is working and the steering is working. If I hadn't messed up the rear left bearing mount, the gears would be fine with no pinching or slipping, a beautiful constant hum. As it is, if the axle moves out of position, you get a little pinching happening and you can hear it in the sound.

    Overall, it's been fun trying to add suspension and steering to a single shaft motor car. I probably wouldn't do it again however, unless I was trying to perfect it for fun.

    Here's some final photos:

    IMG_20180218_161638.jpg IMG_20180218_161704.jpg IMG_20180218_161725.jpg IMG_20180218_161748.jpg IMG_20180218_161821.jpg IMG_20180218_161835.jpg IMG_20180218_161853.jpg IMG_20180218_161902.jpg IMG_20180218_161922.jpg IMG_20180218_162002.jpg IMG_20180218_162014.jpg IMG_20180218_162025.jpg

    Also a final video, no track test, but it's working and drop test seems good.



    I've had fun with this but I think I went too far and it's kind of an average in build quality in the end, definitely plenty to improve up on.

    Overall, it's been fun trying to add suspension and steering to a single shaft motor car. I probably wouldn't do it again however, unless I was trying to perfect it for fun.


    Also one last photo, I screwed up another shell, the DCR-01 this time, so I got some inspiration from an aerobatics team, guess which?

    IMG_20180218_174520.jpg

    Don't have no yellow decals with the lettering US NAVY, but the scheme looks about right.
     

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