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I've been following this thread for quite some time and haven't had much to add. I'd be lying if I didn't say that I was happy to see one shot of the Chiron to whet my appetite. I'm quite surprised at all the leaks from official sources, but it is understandable in my opinion. Shipping boxes to stores in malls is risky. Especially since most of the stores I've been to around the world(over a dozen now :) have employees building sets for display out in the open. Regardless, I'm most upset about Lepin having an identical box with art and likely the fully produced set ready to go on the same release day. WTF? Who leaked the .ldd file(or equivalent) to them? That person needs to be taken to court, not just fired.

As i see it the video hints to an all black Chiron as the rims on the real car in the video match the Lego rims in the teaser photo almost exactly. The real car is all black in the video without even the blue line curving around the door as seen in some paint variants. It could be that Lego chose to display an all black Chiron so as not to give away the real colours. Personally I'm hoping for a light blue on dark blue colour scheme, AWD, and accurate suspension geometry this time. I suppose dark gray on dark blue would be classy too. Why else have an extra 900 pieces vs the Porsche? If it is all extra brick built prettiness on a 2wd chassis I may skip it.

I found this page on the importance of axle reinforcement and ways to do it. I'll be trying these options first and see if it helps.

Over the weekend I managed to fully build one shoe and solved some wheel placement problems as well as started to add structural support for the x-brace and body. I was able to test the shoe and the performance was mediocre. It has lots of torque and does go up and down in gear ratios as needed. Going up an incline seems fine and it is slow as expected. The problem seems to be that the many dive axles that twist and retain a lot of torsional power like a spring that lets loose once the friction on the drive line is reduced. The end result is a lurching of the shoe on flat ground. This is probably exacerbated by the final output shaft having a 1:1 drive ratio with the drive sprocket. I'm going to try a 1:2 gear ratio at the drive shaft. If that fails I'm thinking I have to redesign the cvt to pass power more directly by gears than by axles. I can't see that being possible, but I haven't tried that yet. Anyone have other ideas as how to lessen the impact of axle twist/spring?

After much rework of the same idea, I've got a design that is working. In this image one can see the sprocket solution that I am using at the moment, but it works reasonably well so unless it fails under stress conditions(which is why the sprocket is driven from both sides) it should be fine. A couple more images on the blog including the front side view.

Its nice to see that I'm not the only one working on the floor. My living room is regularly a disaster zone with a 3yr old in the house, The room's explanation is here if anyone would like to read about it.

So the latest failure is that I built the cvt in shoe size and only realized after(in my overzealous attempt at ingenuity) that I used the open diffs in a way that does not work, so back to the drawing board on how to fit it all in.

Fair enough, but I feel a need to try and I think I have improved on the existing cvt design a little. As for all wheel independent suspension I was thinking of 2L rubber liftarms to provide a dense and short travel for the casters, but more on that later. I have made nothing but failed attempts at all stages, but it all comes with learning about the challenge that I have taken on. So the more mistakes the better as long as I learn something to help me move forward. Off topic: my parents are from the eastern block and they got out in 81. I feel like I know what you are talking about from experience with respect to being stuck in communism.

I know all that. Not sure what age you take me to be, but it really makes no difference to the discussion. Lego is highly limited. That is the nature of the system. Thanks for pointing out that liquid doesn't get compressed. I was only pointing out that no hydrolic system exists in Lego, but when one takes the direct energy transfer of liquid in to account a purely mechanical representation is in some ways better than pneumatic. We all accept some lack of realism with Lego. I find it fun to try and make functions that have semblance to the real thing even if it is something as hard to compare as diesel/hydraulic to electric/electro-mechanical.

Yes, well I'm not emulating the hydrolics since Lego has no hydraulic system. I'm trying to emulate the functions of the various components at a high level. The real thing has hydrolic everything. I have Lego pneumatic or mechanical to choose from. As I have more mechanical parts than pneumatic I'm sticking to mechanical. Mechanical also arguably takes less space when trying to cram motors and a transmission into a 35x5x10 brick size for each shoe. If Lego had a pneumatic motor that fit, I'd be all over it... now that I said that a steam engine drive comes to mind... hmm mm.Thinking out loud, I wonder if a cvt or pneumatic drive would be smaller. If the only concession is pneumatic instead of hydraulic then the cvt or at least a 2 speed automatic would still be required after the pneumatic drive segment, but it could have some crazy torque. I still think that a purely mechanical cvt is smallest and able to fit in the dimensions required for the model. If I just wanted it to go at various speeds I'd hook up a couple motors to tracks and use a train PF controller. Just to be clear are you pointing out that Lego has no hydraulic system or that the cvt doesn't work with high torque or that the cvt can't possibly replicate a hydrolic drive system accurately?

Will do. :)

I'm quoting Wikipedia here: A continuously variable transmission (CVT) (also known as a single-speed transmission, stepless transmission, pulley transmission, or, in case of motorcycles, a twist-and-go) is an automatic transmission that can change seamlessly through a continuous range of effective gear ratios. If we look at how various CVT implementations work (Toyota, motorcycles, Honda, industrial tractors) there is such a large difference in internal design that one transmission can not be compared to another except by generic definition of a CVT. I have looked at every Lego CVT that I can find including the un-translated slavic ones. The problems that I found were partially addressed such as in Nico71's use of flywheels. The solution to power loss that I came up with completely solves the problem. The remaining problem of gear range selection depends on the speed and torque of the motors as well as the weight of the vehicle since it is a mechanical speed control. I fully accept the burden of proof on me. I will make a video to show it working. Unfortunately it won't happen soon because I'm gone for most of August and September is always busy with the new school season.

The photo of the excavator shoe implementation is coloured the same as the example photo from the blog. I've included an excerpt for explanation. Power from the motor turns the 16 tooth gear that drives the pink differential that drives a grey shaft and a black shaft. The grey shaft drives the yellow gear set for roughly a 1:5 ratio. The black shaft drives the green gear set for a ratio of 1:13. The two gear sets recombine in the purple differential and outputs to the blue 16 tooth gears.The output power equals the motor's output power at all times though the speed varies within the given ratios. In practice the whole system has a problem with using the low gear side even if the motor could drive the high side exclusively because the low side is easier to drive. A simple solution to this is to add a small rotational resistance to the low ratio gearset(green) before it enters the purple differential. The resistance needs to be equal to the gear resistance of running the high side(yellow gears) so that the green side is not used unless it is truly needed because the motor can not drive the high side.

I see you have reservations about this working, but could you please explain the problem with my CVT design. In the link I posted to my blog I discuss the problems with the design commonly attributed to nico71 and propose a solution. I have built many of these to test out the idea so I am quite confident that it works. I just haven't built a good structure for it yet so I have no video. I plan on posting one once I have a more complete bottom end for the excavator.

Thanks, it is simply an analysis of the problem and it happens that Lego does have a solution. This will be by basis for the shoes. I may still add a friction gear to the low range gear set in case the two L motors don't have enough torque to drive the full weight on flat once it is all together. The friction gear will only bias the gearbox to high gear by default and be overpowered once a real driving friction is encountered.

Any large 1:8 or 1:10 4x4 rally car with modern steering geometry and decent gearbox would be very welcome. I would also like to see a fully working slinger dump truck that can move 1x1x1 round bricks like the BWE and/or 1x1 round plates: If not next year, maybe in a year to come.

Here I discuss my take on implementing a Lego CVT It boils down to this in each shoe: Dark azure is motor in, light azure is output. Green gears are low gear(1:30), yellow gears are "high" gear(1:4).

You've gotten pretty far without knowing what impedance means. I think you know more than you're willing to let on, but regardless, well done! I was always wondering if such a simple hack could be done and clearly it can and done so as to be temporary. I may just do this myself to enable my v2 receivers and a couple remotes to work outside.

Recently it feels like a bit of stagnation on my part while thinking about several problems with the model. I put several pounds of weight on the front of my BWE's arm to stress the LAs and they held up fine so I'll continue to move forward with my doubled LA design cautiously and do another weight test with the real thing later. The problem with the turntable being too small is currently being solved by using a second turntable stacked under the first to pull up on the X frame as well as a brick-built "washer" like ring to spread the weight out more. Something like this is what I have in mind: The turntable ends up being a hybrid of system and technic bricks/beams to spread the weight out and hopefully help with the model's presentation to look more realistic. What do you all think? I just noticed that in the image above the center 11L beam is horizontal. It should be vertical. Another problem to tackle is that I want to implement a 2 speed system in the shoes just like the real thing. I think I will do this with a CVT as it would be nice to have a smooth power out. The problem here is that existing designs loose all power when the output shaft rotation is stalled because they function on internal gear friction. I'm making a version with one way gears on the ratio side. I'll let you all know if it works or not.

Thanks for the comments Steph. The turntable spins with the XL motor and the boom plus arm stretched out all the way, but it does require a higher gear ratio. I'm hoping to carry a full bucket of small bricks and that will add a lot of weight. I will try a full load test soon to be sure it behaves as desired with the XL motor. Oh dear. That is exactly the setup I have isn't it. Hmmm I must have gotten lucky to not have the rams spin the plastic bit around the end. Is it possible that the newer LAs have better internals for this connection? When the paired LAs reach their limit the internal limit clicks are heard just like the Volvo loader when it reaches its limits. There is also a small difference from that diagram and how I have them setup and that is that the plastic end is entirely locked in the direction perpendicular to the turntable which hopefully keeps any wobbling to a reasonable minimum. I had rebuilt the gear set for the boom cylinders yet again and just got it to fit: I'll reconsider the LA drive system. Maybe I can get the double length LA in some other way while still using LAs. Maybe driving them from both sides using the stock brackets like on the Volvo loader. That at least would remove the turntable friction. I still can't imagine that the LA wasn't designed to handle rotation of the head since the head rotates when run without being connected. TLG must have considered this since the new ones have an internal clutch that I don't think can be defeated, but I'll be cautious and run my own tests first. If I destroy an LA it is better than all 8.

Wonderful design and details. I love it!

I'm most happy about the 2x BWE that I got last year for $200CAD(157USD or 137EUR) each. I have one copy on display and the other is in a WIP.

That could be. The torque is not normally applied to them this way. On a previous version on my A40F I had them joined on the rod ends in the middle and free spinning on the drive end achieving the same extension result, but ultimately that has the same problem because of the need to have one end free to spin. I would love to see any problems with this type of setup. Do you know roughly what topic this was under so I can narrow my search? On an update note, http://cloudslego.blogspot.ca/2017/07/ec750e-boom-drive-part-2.html has another iteration of the LA drive gear sets as the one from yesterday was too wide. Looks like this now: I haven't had this problem with the new design as long as the small gears are well braced on either side and unable to pull away from each other the split sides with drive in the middle has worked. A final play test carrying a full bucket load at full extension will show any remaining faults.

I had two actuators before, but was driving both from one side without splitting the power. Now it splits in the middle and is more reliable.

While I wait for the wheels and various parts to arrive for the tracks, I've tackled the boom drive problem. At least for now anyway it feels much stronger.