2GodBDGlory

Ooh, nice work!

That's pretty cool, and impressive that you were able to build it around standard size cylinder elements!

So, the first thing I did after my last update was to start changing gearing to make this truck faster. I added an extra stage of gearing in the axles after the ball joints, with a 20:12 ratio being the largest I could fit in. This gearing also allowed to keep my axles flatter, with the advantage of giving me neutral castor angle and even ground clearance, rather than backwards castor angle and uneven ground clearance. The second gearing I was able to change was switching the portal axles from 1:5 to 1:3, with 12:36 gearing. This was a bit disappointing to have to do, since portal axles are really where you want to keep as much reduction as possible, but I didn't see anywhere else where I could change gearing without compromise. If I decide I need it still faster, I'll probably have to find a way to increase the drive ratio of the bevel gears in the axles, but that would either require a lot of rebuilding, weaken the components a lot, or introduce unevenly operating knob wheels. After getting that done, I moved on to bodywork! I had decided that I wanted to use these custom-painted 1:8 car wheel arches, but mounting them normally in the front would result in them sticking out two studs farther than the front, because my Niva has the wheels pushed out to a non-stock location in the extreme front. Rather than forget the wheel arches and bore myself building another 4x4 with basic beam-stacked sides and slope-brick wheel arches, I decided to mount the wheel covers at an appropriate angle to still cover the wheels. It looks a little odd now, but it allowed me to use some panels to fill in gaps, which looks fairly nice, I think, and at least different from my usual! I've started trying to find a place to mount the rear wheel cover, but my rear-wheel-steering system is complicating this. After getting these wheel arches figured out, I moved on to the front. I'm super happy with how the orange/white secondary lights turned out, fitting nicely into some black System panel pieces to provide a realistic black rim around them. The grille wasn't too complicated, but the bumper unfortunately couldn't reach the full width of the car for fear of colliding with the wheels at full steer and suspension travel. I'm quite happy with how it's looking so far, though, and I think this should become something that's both fun to drive and fun to look at, which isn't something I could say about a lot of my off-roader models!

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!

Looks fun! Are you planning on making it RC? If so, you're going to have to be very careful with bracing that gearbox, because 6-speeds add a lot of friction, which makes skipping gears a very attractive alternative for the motors to take if possible!

Mine had a sequential, but if I were to build one again today, it'd probably have a remote-controlled 6-speed manual, using two servo motors to allow for joystick control from a remote (This is a system I've used on my most recent Ford Mustang and Ford F-Series MOCs, and it's very fun to operate!).

I actually did make a 1:8 one a few years back, but I'm sure a lot could be improved, so good luck!

Nice! It's always interesting to try FWD cars, so the Type R should be interesting.

Yeah, that's strange! You can see it at 0:33 too.

That's neat that we get that gear in black. I wonder why they needed it, though! It's certainly one of the gears that didn't need a recolor into a more inoffensive color, but it's nice. I'm really glad to see those Technic baseplates there! It's a better color, and will hopefully make those things cheap enough that I can finally justify buying some!

Do you have to have a 9-speed? By the nature of Technic gearboxes, it's usually very difficult to go beyond 8 speeds, and 9 would be a real challenge. If I were building a car and really wanted to have a realistic 9 speeds, I'd probably try using something similar to this old 12-speed design of mine, and then just ignore/block out three of the speeds: A great tool for calculating gear ratios is Sariel's Gear Calculator app Good luck!

The need for the brackets probably just went down a lot when the longer cylinders came out, I'd guess

Thanks for posting this! I recall seeing it on YouTube, but it's always nice to read some more details!

Thanks! Yeah, I realize that I have excessive gear reduction at the moment. I have as much as I do in the gearbox just because I wanted my two ratios to be as different as possible, but now I'm going to have to change my gearing down the line to be faster. I've built several heavy-duty off-road models with brick-built hubs before (though of a different design), so I'm hopeful these can work, and will provide much better ground clearance than planetary hubs.

After determining that my method of bevel gear power transmission was a dead end, I felt stumped for a while. How could I eliminate those bevel gears while keeping reasonable suspension geometry and the gearbox? In the end the solution I struck on was to design a gearbox based on a 5 stud spacing rather than the 4 stud spacing of the earlier design. There aren't many gear ratios that work at this 5 stud spacing, with the only options I know of being 56:8, 40:24, and 36:28. [Well, I just checked and 9:15 (with old, pre-Technic gears), or 6:10 (with splat gears) both work, but are both actually identical gear ratios to 24:40] This was probably the time when I most wished the 48T spur gear from the The Lego Movie version of Emmet's Super Cycle had made it into production, since a 48:16 ratio would have been great! (According to something I read somewhere sometime, it was planned for production, but budget cuts forced them to use a standard 40T gear in the official set) I actually didn't realize 56:8 was a possibility until later, but I'm sure I wouldn't have tried it anyways due to impractical size and pathetic 8T gears. That left 40:24 and 36:28, but wanting the largest possible ratio spread, I opted for the 40:24 ratio and its opposite, 24:40. This meant that my already unsynchronized gearbox would have the added disadvantage of straight-cut gears trying to slide into each other, but so long as the drive motors are turning, it hasn't had trouble engaging. The spur profile also allowed for a neutral gear to exist in between the two speeds, thanks to the two 1/4 stud spaces between teeth and the edge of the gear adding up to the 1/2 stud of the width of the gear teeth, which prevents jamming when shifting. Anyways, this gearbox was able to fit into a space only three studs long, which was crucial, and it allowed the XL motors to be mounted linearly with a three stud space between them--perfect for fitting part of the suspension ball joints between them! This gearbox is shifted by a PF M motor through a large linear actuator, through a 4-bar linkage, which I found to be the best way to transmit the linear motion of the actuator down ~6 studs to where the gears were without losing motion to part bending. Redesigning the gearbox also meant redesigning a fair bit of the frame, but other than that not much has changed. The new gearbox has a much lower high gear, though, and it was already slower than I would have liked, so I'll probably have to find a way to add significant upgearing later! It'd be easy to swap the portal ratio from 1:5 to 1:3, but I'll probably have to dig into the axle drive ratio to get the change I desire. I've already snapped this 8L axle simply by its twisting in the ~1/2 stud space between the 40T gears and the wheel hubs in the portal hub assemblies (in high gear!), which seems like a good indication that I have abundant torque to trade for speed! Also, I finally took a look at that video you linked, @Daniel-99, and those are some pretty extreme machines! I thought my 8:40 portal axles were the craziest anyone had done, but those 8:56 ones put me to shame! It's a really great idea, though, and one that just might convince me to buy a couple more 56T turntables sometime so I can try it!

Hmm, that sounds like a challenging, though interesting, project! If modified valves are too expensive for you, have you thought about modifying them (even starting off of clone ones) yourself? That could save you a lot of money, and still probably be less effort than 3D printing.

True, I wouldn't really call it a truck either, but to me "Trial Truck" is just terminology that I slap onto anything I build that's intended for heavy off-road use, and it's especially fitting for this one, since I plan to enter it in a "Truck Trial" event. Yeah, it will look a bit like a monster truck I think!

I love that strategy for combining the small LA with that bevel gear frame! It's something that looks super helpful, and makes me wonder how I've never seen it or thought of it before!

That's a neat design, and looks like it might have a chance of becoming practical with enough reinforcement, which can't be said for most CVT designs! You might be interested in taking a look at this topic, where I did a somewhat similar design, though with some important differences:

Ah, sorry, I see what you meant!

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!

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!