2GodBDGlory

Except for the 8455 Backhoe, with its out-there 10 cylinders!

Part 77765: It's fairly new, but rather handy!

After finishing up those little jobs, I was able to do some basic first tests. The takeaways are: This is a beast on power! Even in high gear, it's got all the torque it needs for climbing! To make the most of the power, I'm probably going to have to find somewhere to raise gear ratios, so that low gear is actually useful! 12T single-bevel gears aren't as strong as I thought. The bevel gears I set up to take power from the XLs to the gearbox were popping energetically when I gave it full power under load, despite having four of these gearings (one per motor) to try to split up the torque, and despite the solid bracing! I'll have to see what I can do about that. Anyways, it looks like I'll have more work than I was expecting, but that's why I started building so early!

I'm back with a weekend update! I was very happy with both my axle and my gearbox, but unfortunately, they really couldn't work together in a model with as short of a wheelbase as I was building, so one of them had to compromise. I decided to keep the axles and modify the drivetrain, adding bevel gears between the XL motors and the gearbox. This adds a decent amount of friction and complexity, but allows my axles to come close enough together, maintains the gearbox, maintains the power level, and should still be reliable. I've added the rear axle, which is essentially just a copy of the front one, because I want to include four-wheel steering here. It should allow for tight turns, even with locked differentials, and allows me a decent amount of wiggle control over the independent front and rear axles to help fight for traction in tough spots. The suspension seems quite strong as it is (though I still need to take the other ball joint out of my Land Cruiser), but is a bit lacking in flex. I'm not sure how much of a problem that will be! Additionally, even though tests showed the gearbox as reliable under torque, I didn't want to take any chances, and so I added a 7L beam in the middle of the sliding assembly that slides along with the gears, ensuring great reinforcement in both gears. I replaced the small linear actuator for shifting with a large actuator (not clearly seen in these pictures I took, apparently), to take advantage of its stronger clutch strength. Now I mainly just need to hook up a motor for shifting, reinforce the frame a little, and install the electronic control elements, and I should be ready for some preliminary testing!

Yeah, I'm quite happy with the portal design! There's a bit of friction against the rim, and a very specific spacing that works for the 3x3 L-beams, but I think they look good and strong. I'll definitely have to see how the 4XLs perform, but I'm counting on the fact that there's not much reduction prior to the portal hubs to keep it all together Huh, interesting! I guess mine will be an even more heavily modified example than I was planning! That's true that 4 XLs aren't the normal, and it might be challenging to cope with their torque, but I think their form factor is good, and they're reportedly better than buggy motors when high torque is required, though I've never really figured out why. According to Philo's stats for these motors at 12V, though, 4 XL motors at 12V will give me 12.96 watts, while 2 buggy motors at 12V will only give me 12.32 watts, so I don't think I'm giving up any power there, and the shape is more convenient. I think that scenario you're describing is a good high-performance setup, but to my ear sounds more optimized for higher speeds than I'm planning on. The primary objective with this thing is to be able to crawl over pretty much anything possible, and then to have as much available speed as I can get, given the crawling ability.

I don't usually do WIP threads, but after seeing @Teo LEGO Technic start a WIP topic for the truck he's building for this Toronto Trial Truck race we're trying to organize, I figured I might as well document my progress as well! Anyways, I'm most comfortable with 4x4 off-roaders, and I only have 4 (well, actually 5 if you count my spare one that spent a winter lost in the woods being chewed on by animals) 107mm tractor tires, so I started looking at attractive short wheelbase 4x4 SUVs. My desire to do something I haven't built before limited me a lot, because back when I had less responsibilities/more free time I built a LOT of different vehicles, with varying degrees of quality! I made a shortlist of models, but wanted to do something a bit oddball, so I eventually settled on the Lada Niva: I don't suppose this truck needs a ton of introduction in Europe, since I hear they're fairly popular there (Probably more in Eastern Europe??), but for any Americans who haven't heard of it, it's basically a small, very basic, Russian-made SUV that's been in production since 1977, and is apparently still produced in roughly the same form. While this vehicle was never sold in the US, it was in fact sold in Canada, and I can remember seeing exactly one in my life, though that was in a junkyard. Anyways, I think it looks cool and has an interesting history, so that's what I'm building! My model will probably attempt to look like a fairly heavily modified example, with larger tires, a solid-front-axle swap, and some accessories. The planned features are as follows: 4WD with 4 PF XL-motors hard-coupled together 4-wheel-steering with one PF L-motor per axle 2-speed sliding-gear gearbox controlled by some PF motor The first thing I built, after mapping out the ideal gear ratios in my head, was this gearbox setup: It looks like the gears should be reinforced well, and I like the large difference between speeds and the efficiency of the setup. I'm not sure how much I trust the small linear actuator to successfully slide these gears along the axle, so I'll likely tweak that, but the other thing I dislike is that I can't get the ball joints I'm hoping to use for the suspension anywhere near the middle, which will hurt my suspension geometry. Nothing obvious presents itself to solve that, but we'll see how this fits with my current wheelbase and see if anything comes to mind. After that, I built this axle, which I'm quite happy with: It's got a new custom portal axle design of mine, which gives a steering pivot in about the best possible position, a 1:5 gear ratio, and good ground clearance around the wheels. Of course, this also gives exceptional ground clearance in the middle, with over 8 studs available! The main axle drive has got the "square" drive technique I was describing in Teo Lego Technic's thread, with 12:20 ratio for better ground clearance than typical gearings. The steering has a PF L-motor driving a 13L rack through two gears individually, one on each side, through a parallel gear setup that goes 8:28, 8:24, then 16:20, for total reduction of 13.125:1, and nice symmetry and strength. Next I'll probably either start thinking about working ball joints into the gearbox assembly or build a clone of this axle for the rear--I've just got to take apart my Land Cruiser MOC to free up those ball joints soon!

In my experience, stuff from there usually arrives in about a month, though it's hard to say, and sometimes my orders have missed some stuff. It's probably not ideal if you're counting on something to come on time; I've always just been stocking up in advance. Yeah, the new CV joints allow for quite acceptable steering lock. I first used this setup on high-powered MOCs with a non-Lego motor, and the main purpose was to try to avoid destroying parts! I absolutely had to lubricate everything in that application, but I generally don't otherwise. It definitely is more friction than just a single meshing, but in some models reliability has to be prioritized! It is somewhat hard to assemble, because if one of the gears gets a tooth off, it won't go together well, and will add a lot of strain to the assembly. It's possible that that could have happened to yours if the friction is really excessive, though I'm guessing you did it just fine!

No, I haven't tested that, and I don't think it would work well in this particular model, simply because the suspension is very soft, and not optimized for heavy loads. I think the axle could potentially work for towing, but there's probably a bunch of things I'd change for that. Probably lower axle gearing with 12:28 or 12:36, and then I'd reinforce the bottom half of the axle better. Here I was trying to keep a lot of ground clearance, which limited the reinforcement I could do on the bottom, but I think a more towing-focused MOC could sacrifice clearance for strength. I didn't have any issues with steering and my locked differential, but I also had an unfortunately low steering lock, so I didn't really anticipate any problems regardless of what I did with differentials! I think I could have gotten away with a locked front as well easily. Thanks! I'm quite liking the power and control of this setup, though it is a bit unwieldy to set up

Thanks for the nice comments, everyone! I really appreciated your thorough response, @Daniel-99, so I'll try to answer your questions: Yeah, I decided not to go for opening doors, largely because of rigidity, especially given the half-stud indented portion of the sides, and also because the interior was filled with functional elements, so it wouldn't look good with doors open anyways! As far as the steering goes, I did think about using GeekServo with this RC setup for a while, but I'm now convinced that it can't work for me. The trouble is that my RC setup isn't actually a hobby RC-style one, but rather cheap replacement parts I ordered that matched this ~$100 RC car my brother had. It offers good control for the drive setup, and I have the original steering motor from the setup which can be used as well, but the trouble with GeekServo is that this board has non-standard servo control. Instead of a normal 3-pin setup, it has 5 pins, two of which are wired to a basic non-servo motor used for steering, and the other three of which are wired to a potentiometer that sends position signals back to the board, telling it when the desired position has been reached. I actually made a 3D-printed housing for this potentiometer and custom wiring that would allow me to use any PF motor for steering, so long as the sensor was attached to the steering shaft, but the printed part that interfaced with the potentiometer had to have an extremely thin part, and always broke, so it wasn't reliable. Additionally, the steering parts of the control board don't seem able to survive the 3S setup without dying, so when I was using that, I actually had a second identical control board on models with a secondary 2S power supply to run it, and a second remote to carry. So, I guess the short version is that I see no way to use GeekServo with setup, because of completely different steering logic. It could be fun to get actual hobby-grade control hardware, but it looks pretty expensive, and this works pretty good. The MouldKing box is actually surprisingly light for its size! You're definitely right that problems are caused by having driveshafts of shorter length than the suspension links, but I'm not sure how I could practically solve it here. The front driveshaft is already as long as I can get it, because I was getting excessive wear when I tried having a HD CV joint on the top of the driveshaft. I suppose I could go to 6L suspension links, but then that's going to create more longitudinal motion of the axle throughout the suspension motion. As far as these three suggestions go: I think the driveshaft is nice and parallel, at least without compression, and there seems to be minimal wobble. Why would you suggest brick-built links? My feeling would be that these would be strong enough in compression and tension, and wouldn't deal with other forces much, but I could be wrong about that. Unfortunately, I think the only satisfactory way to solve my suspension issues without creating different ones (though the new issues might not be as bad) would be to increase my wheelbase, which isn't really possible in a scale model like this. You asked why the anti-roll bar is on the back, and I guess that's because of an impression I had that that was more normal in real cars, though I guess that was wrong! Additionally, it was a bit of an afterthought, and I think I thought it would be easier back there. Looking at the model now, though, I see that I could just connect the front suspension levers together with an axle to put the bar up there, which wouldn't be very hard! Sadly, this MOC won't be staying together long, because I need the parts for another MOC I'm working on right now! Thanks for the reminder about chassis pics! I took those, and meant to post them, but somehow I forgot. Here they are: I think in general in Technic MOCs the anti-roll bar is counter-productive, because we definitely do want that flex! I think it was more necessary in my case because of the rubber band suspension I was using, which doesn't really have limits, and is very soft. Probably a suspension with springs wouldn't need them so bad. Based on the tests I've seen, clone buggy motors are slightly weaker than original ones, and Buwizz ones are slightly stronger, so there probably would be a notable difference here. Maybe I just needed more speed to be satisfied, though!

I think this is my fourth model of a Toyota Land Cruiser 70 now, so yeah, I like these trucks. I've now done the 2-door SWB SUV, the 2-door LWB Troop Carrier SUV, the 4-door pickup, and the 2-door pickup, so I guess the only major body style I haven't done is the 4-door SUV. Maybe someday! Anyways, this model was made to try to make a model that would both look good and perform well, and I think I was fairly successful in that! I think I talked about the wheels I'm using in a different thread, but they're ones I custom-modeled and 3D-printed to match the LC70 style. They are stretched in diameter a bit beyond the standard Lego Racing Small rims so that they can clear planetary hubs, but they still work fine with these 81mm balloon tires, and, I think, look really cool! Aesthetics: Functions: Folding bed sides Drive Steering Suspension Folding bed sides The three sides of the bed all fold down, as it appears some Australian-spec beds do, but I don't seem to have taken any pictures of it. I think it might be in the video, though. Drive Drive was done via two clone buggy motors, powered by a custom 3D-printed case for a 3S lithium battery, outputting nominal voltage of 11.1, just like a Buwizz, and a 2.4 GHz controller. Output came from the fast outputs, was sped up by a 20:12 ratio, and sent to the axles, where it met 20:28 reduction, followed by planetary hubs. The rear differential was permanently locked, while the front was left open. I think this gear ratio provided a respectable top speed, but also enough torque (even at lower motor speeds) to do about as much crawling as the ground clearance and approach/departure/breakover angles would allow. Steering Steering was done with a PF Servo motor, controlled by a MouldKing 6.0 battery for proportional control. Strangely, I actually ran the steering with an 8T gear attached to the Servo's rear output, which ended up right underneath the motor, which is certainly technically illegally close to the motor, but which actually worked quite well, and was quite compact. The use of only an 8T pinion really limited steering lock, though, which was a bit of a problem. Other than the low lock, the system worked quite reliably and well. Suspension This was the function that took the most trial and error to get working. Both the front and the rear had triangulated 4-link systems with a significant amount of travel. The rear was simply sprung with some orthodontic elastics that had to stretch upwards when the axle went up, while the front pushed 6L links upwards, where they had to rotate a lever that would stretch large rubber bands. These link and rubber-band based systems allowed for smooth, low-friction operation and good articulation, but in the end I had far too much articulation, so the truck would often find itself rolling over even when just taking routine corners at high speed. To remedy this, I installed a basic anti-roll-bar in the rear, which had a very dramatic effect on handling, really preventing that level of body roll! I was quite pleased with that, since anti-roll bars seem to typically be included in Technic MOCs as a novelty, but this proved that they can have huge effects on certain models! Performance I think the truck was fast enough to be fun, and had very responsive suspension, making rough terrain a lot of fun. The biggest issues were the fragile body and its tendency for its front driveshaft to fall apart. Probably in the future I should stick to simpler ball-joint based suspensions, even though ones like this are fun to design! Complex Variant: This model was actually originally designed with a completely different chassis, incorporating some more complex features. Unfortunately, they slowed the truck down dramatically, so I completely redesigned the chassis. Originally, it was driven via two PF L-motors, through a remotely controlled two-speed transmission, into an inboard rear differential, which had @JoKo's clever auto-locking differential design. I mounted the differential inboard to avoid having to push the bed too far above the rear axle, but this inboard placement added a lot of complexity, making the truck pretty lame to drive. I still love the basic diff lock concept, but I don't think this was the right model to try it in. I've got a basic video of that early version here: Summary I'm quite pleased with this model. A bit more reliability would be nice, but performance was fun, and I at least really liked the way it looked!

Bricksafe is the one most of us use, and it's quite convenient

I mean, there's always AliExpress ones, depending on how you feel about that. I haven't got any of those, but I have been tempted. My typical strategy for high-torque bevel gear setups is to do a sort of "square" setup to split load among more gears. For example, in my current WIP, I've got a 12T double-bevel gear on the input part of the O-frame, driving a tan 20T double-bevel gear that drives the output shaft. This is where a typical MOC would leave it, but I go a step further, and put a second 12T gear on the opposite side of the O-frame, so that it is meshing with the tan 20T, and then put in a blue 20T clutch double-bevel gear on the output shaft so that it meshes with both 12T gears. It rotates in the opposite direction of the tan one, but because it's an idler that's not a problem. A similar strategy can be used with 28T gears, by using just the red gear off of the new differential and a standard 28T gear.

Nice to see your progress! I've got a decent bit of work done on my model for that race, so maybe I should start a WIP thread sometime too. I would wonder about how important the differential locks are. In my experience, permanently locked ones are more reliable for crawling, and don't hurt steering too much on low-traction surfaces.

No, sorry. If you have specific questions about something I can answer I'd be happy to help, but I think the working principle is simple enough to copy

Good to know! I seem to remember The Unofficial Lego Technic Builder's Guide suggesting the opposite, but those tests look convincing, and make sense to me, so I'll change my practice.

After finally getting a couple of the new spur 20T clutch gears, I was struck with an idea for a new gearbox setup I could make, making use of their ability to drive chains. Because of this, and the new 12T and 20T spur gears, there's actually a lot of options for gearing, which can be done in a straight line, much like a real car's gearbox. I built two versions of this gearbox, which were a bigger 5+R gearbox, with these gears: R: 20:28, direct drive rather than chain 1: 20:24 2: 20:20 3: 20:16 4: 20:14 5: 20:12 By nature, this gearbox is very close range, and the fact that I used the old and chain-capable 14T gear to get a fifth speed makes some speed changes extremely small. Additionally, doing six positions with the wave selectors is tricky. I did it by offsetting them by connecting them all to another axle beside it with 12:20 gearing, which, because 12 is divisible by 3, allowed me to space three of them apart evenly, making only one ring engaged at once. Because of these reasons, and its size, I figured that most people wouldn't be interested in using it, so I also built a much more basic 4-speed version, with 20:24, 20:20, 20:16, and 20:12 gears and a straightforward wave selector setup. Unfortunately, I took it apart last night after it had been sitting on the shelf for a while, and only just now realized that I didn't take any videos of it... It should be pretty easy to figure out how it would have looked based on this 5+R one, though. I'm not sure how the chain would hold up to heavy use, but it is a refreshingly straightforward way to get lots of speeds in a Lego transmission! By the way, I only had two of these gears from Lego, so I had to 3D print the other four. It still worked fine!

3: 10 1: 6 10: 4 7: 3 2: 2 11: 1

I'm very impressed, especially given that it's an alternate model!

No, that's not what I meant. My understanding was that the trans-clear plug part on the Buwizz popped out and was flopping around, and that it could be glued in place. However, your response makes me think that's probably not the issue, and that I should probably just be quiet given that I've never even seen a Buwizz!

Oh, I was thinking to glue the whole plug in place, making the clips irrelevant.

Though the (I assume) unofficial fender colors would probably disqualify it from a contest, I assume.

It might not be the best solution, but if I'm picturing the situation correctly, I'd probably just try supergluing it back in place

Interesting use of those wheel arches in the front; I like it!

Impressive work! I always like seeing your progress on this project.

Yeah, that's happened to me with lots and lots of PF components. I've usually fixed it by opening it up, cutting out the part of the wire where it enters the device, and resoldering the shortened wire back up. It's harder with receivers, though, because they need 4 wires soldered to a PCB.