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amorti

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Everything posted by amorti

  1. amorti
    Is that with Lego battery box and IR receiver? V1 or V2? Buggy motors can take 3.2A stall current. IR v1 gives 0.4A per channel, v2 gives 1.5A per channel. The normal battery box is 0.75A fused. So you'll trip the safeties on the battery and control unit waaaay before the motors. On the other hand Buwizz gives 4A continuous with 6.5A accepted for a short time. So if you're planning to upgrade the power supply, that's when you'll see stuff break. If you're not, you're going to be disappointed with what your 2 buggy motors manage.
  2. amorti
    They might be fine for a while, but I have busted several U-joints and also snapped the heads clean off of CV joints on several occasions, and I'd say that's where this would go too. If it does that, either drop the suspension and use a straight axle instead, or try those turntable hubs from didumos, and use metal u-joints through them. Or turn the buggy motors around to be used as swingarms, ditch the differential (there's at least a small chance that'll spit its gears out, btw) and the joints in one swoop.
  3. amorti
    Keep it light and you might be ok, but you're definitely going to find out what it sounds like when a U joint snaps eventually. Keep the U joints as flat as you can, keep both ends as well supported as you can (e.g. mount the wishbones and wheel hubs with friction pins, not loose pins or axles), and say a little prayer each time you flick from forwards to backwards on your control. Might be worth looking at whether you could use universal joints both top and bottom, rather than CV joints. Then you can use metal u joints. https://rebrickable.com/mocs/MOC-11088/Didumos/turn-table-based-wheel-hub/#details Edit: is that a universal joint at the top of the driveshaft which doesn't have its pivot aligned with the suspension pivot? I'll leave this here
  4. amorti
    I guess there's nothing stopping you using CaDA motors and Buwizz batteries. I may yet try it because the pinned together remotes are not exactly ergonomically optimal
  5. amorti
    Got it. I didn't think it could get more dense with gearwheels in an RC model! Very cool, but I'm not going to tear back into the drivetrain at this point ? Video to follow, then. @brunojj1 Do you have a driving video with 2 Buwizz and 4 Lego motors? Did you try building it from CaDA pieces / with CaDA motors yourself?
  6. amorti
    As mentioned above, CaDA motors are around twice as fast as Lego motors. Even at 8v, it's quick enough for me in the configuration shown. At 2.6kg (I guess a little more now), it's not about to drift, but it's quick enough to be a handful for driving indoors. I should make a video.
  7. amorti
    Not quite as elegant as two buwizz, brickcontroller2 and a gamepad, but it does switch on and connect quick. You may note I moved the hood prop to the outside of that frame; gives everyone a bit more space and makes it easier to close the hood. And for anyone wondering about getting the hood to close nicely, try this:) I even found the two necessary 3L axles with studs in my spares.
  8. amorti
    If anyone was thinking of adding the extra motors, you definitely want to do it during the first build process. It involved a fair bit of disassembly and some severe cruelty to plastic, to add them in after the fact.
  9. amorti
    The front hubs are much better than the current ones, as the ball joints can't pull out.
  10. amorti
    Yes then we do agree, because the same weight is being applied to the spring so it compresses the same amount of its travel. Or at least it sounds right. I feel like I'd need to build a test rig which took that to extremes, to actually prove it to myself.
  11. amorti
    In real vehicles, suspension springs are measured in kg/cm. Or, how much weight it takes to compress the spring by X amount. There's no other wizardry in a spring: apply a certain force and it'll compress a certain amount. So it follows that if you get more travel, you certainly do have softer suspension as the trade off.
  12. amorti
    Not sure if you shared that here but I've seen it on YouTube and in person. Amazing how the four wheels are glued to the ground, all the time. It's clear to see how this lets the car drive faster than if it's hop-skipping around the whole time. Btw, it gets even better if you fit some soft 1.9"x120mm RC crawler tyres :)
  13. amorti
    So... I now have the extra two CaDA motors waiting to be fitted... I'm just waiting for a couple of 55615 connectors in a bricklink order, to apply @astyanax's method, although I might be too impatient and do it over the weekend with 48989s. Shouldn't lose too much strength by that. I set up a quick test rig of Lego Vs CaDA L motors. There's a really significant difference of around double the speed (I'll measure more accurately if anyone is interested), however just from the 'can I grab and stop a 36t cog' test, the torque seems pretty similar. I'll run it on two CaDA boxes with two of the joysticks linked physically, as I'm confident 8v is going to be plenty for this. I'm not sure how happy the CV joints will be at 8v, but I am sure this thing's going to be quick. The buwizzes can stay in their current home, all they'll be good for over the CaDA boxes is snapping CV joints.
  14. amorti
    In fact they're (about) √50, so just over 7, long. Marginal difference which will give slight toe out, although in an ideal world you'd want toe in on a powerful RWD chassis. Now you have a steering link which (ball joint to ball joint) doesn't run parallel with the wishbones. It won't be perfect, but at least the link is in the same angle and of the same length as the wishbones. You're the one holding it in your hands who can test if it'll be acceptable or not. If it's not acceptable, would it be so bad to use 8L wishbones and links? More track width equals more stability, and you're going to need that. As Columbo said: just one more thing. You've fixed the rear hubs using axles into pin holes. This gives an unnecessarily wobbly connection at a point that needs all the stability it can get. Flip those 90° connectors around instead, use the pin holes for the hubs.
  15. amorti
    That's a lot of functions in a 19 stud wide car. Hats off!
  16. amorti
    Rear suspension is pretty cool, gives a flavour of a multilink setup as this car has IRL. Didn't fancy getting into McPherson suspension up front?
  17. amorti
    Bump steer is exactly that: as the suspension bounces, the wheels either toe in or toe out. Your chassis definitely has this, and with the speeds it will achieve, it definitely will be a problem. Honestly, now is the time to fix it. "Not sagging" means it's too stiff. When you jack up your real car to change a tyre or brake pad, think about how much jacking it takes to get the tyre off the road.
  18. amorti
    Cool concept! But I do see a fairly fundamental problem. The front wishbones are 7L, but the steering links are 6L. This means you will have bump steer. You do not want bump steer! Try again using normal 6L wishbones, and mount a single shock inside their split. The lower mounting of the shock will reduce the leverage the wheel has over the shock, increasing the stiffness of the spring. In general, you probably want the suspension softer than you think you do. The ideal setup uses around 30% to 50% of the available travel as static sag - exactly as in a real car. With that type of suspension, the car can float over bumps, instead of bouncing around over them, losing traction and control the whole time. @Didumos69's greyhound demonstrates this perfectly. Ps: It's well worth YouTube searching that model for examples of how it floats over terrain
  19. amorti
    Yeh. You'd have to go 8:16 at the crankshaft end, and take the chain from there to the camshafts on equal sized sprockets, probably 16t unless 24t gave better chain tension, less noise, etc. Not really how it works IRL but sounds closer to IRL than having gears meshed up the front of the engine. You could then make a chain tensioner with a little pulley wheel and an elastic band. Or maybe a soft shock, but probably too big and too much force. Are there any tracks that could be used as a belt?
  20. amorti
    That doesn't work, so you'd have to do the gearing before and/or after the chain.
  21. amorti
    The two parts are the technic bricks with two holes. You might want to use 4x Lego technic bricks here, since it feels like maybe the CaDA studs are a little loose into the fence? Could be normal though, this isn't a type of connection I've used often! They're like 5c a piece with your next Bricklink order. They're really easy to get to afterwards too, so it can definitely wait.
  22. amorti
    Considering it can measure current - would it be possible to program something to soft-limit (rather than hard-cut) the max current available to each motor? I'm thinking that might help to avoid crunching gears and CV joints when changing direction, etc.
  23. amorti
    I'd love to move up to buwizz 3.0 for the range and power, but my 3 favourite "permanent" MOCs have 4x L-motors each. One has 4x CaDA motors, the other two have 4x MouldKing motors, each of which are higher power than, so draw more power than, a regular L motor. Even if one buwizz 3.0 could output enough power for those 4x PF motors, one PF port is needed for steering, so it'd have to do it all on one port, which seems somewhat unlikely. So, upgrading will have to wait until I have a few more PU motors, and given the cost of the sets from Lego that may take a while. There again, you can buy PU motors for 10-15€ each, and considering they work as reliable servos, that's really cheap as the unreliable PF servos are 30€+ each now. Actually.. I think my earlier question of whether buwizz might make a new PF servo has just eaten itself. What's the point, when PU motors are so much better as servos?
  24. amorti
    Cool! Buwizz is pitching in with PU, and the very fact of this may mean AFOLs switch to it too. @Zerobricks will the 2.0 continue to be offered? Could it become a 2.1 and get the improved internal components mentioned on that page, for better range and power output? I'd buy one, as if it had higher current output you could replace two 2.0's with a single 2.1 and have less weight and volume, but more range.
  25. amorti
    As @nicjasnohas highlighted, this motor is pretty large. If it doesn't fit in his Sierra engine bay, then there isn't a Lego car that could use it. In that case this is a model to set in an engine stand and enjoy on its own. So a chain makes sense; it's not going to drag in the wheels of a car as you push it around, it has an L motor spinning it.
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