Teo LEGO Technic

Thanks!

Hey Eurobricks Technic enthusiasts! After being asked recently if I would enter my latest MOC in a race, it occurred to me that it would be pretty cool if we could have trial truck races here in Toronto, Canada as they have in parts of Europe, like Sariel and his crew in Poland. @2GodBDGlory and I are both based around Toronto, and we decided to try to organize possibly the first Toronto-based trial truck MOC race, so we're calling on all builders in the area to see how many people we can bring together! Everybody is welcome, and any information anyone has that could help us out is welcome as well

Thanks for all the positive feedback, everyone! It's nice to see the final result is appreciated after all the work that went into it Thanks guys! Thanks, @Zerobricks! The gearbox worked well I thought, the only issue is you have to come to a complete stop between gear changes to avoid jamming gears. 7 x 11 frames would have probably been a good choice as well for the axles, I just avoided them to keep the size down to make them more realistic. I avoided locking the diff directly because, to ensure the best gear meshing and no slippage, I wanted to place the diffs inside the 5 x 7 frames. Those portal axles from the Tiger look much more robust, if I had come across them before I would have used them. I currently don't own the new CV joints, but if you say they're better I will purchase some. And yes, I would love your help on my next project, your models are awesome! I was thinking for my next project to attempt a pure rock crawler, with the one goal of optimal offroad performance in mind. Thanks, @Milan! I definitely recommend using this gearbox design, I found it worked very well. Unfortunately, I'm not aware of any trial truck races around Toronto where I'm from, although I'm trying to find Technic enthusiasts in my area to compete in races with through ToroLug: http://torolug.ca. If anyone knows of any Toronto-based Technic builders please let me know, it would be awesome to have some trial truck races like you guys have in Poland and other parts of Europe

This build is just astounding! I have no words, I'm simply amazed this thing is actually made from LEGO - I can't believe how seamless the panelling is, and the rear engine bay in particular is a work of art with the yellow and purple complementary colours and golden highlights. This is one of the greats in my opinion

Hey everyone! After almost a year and a half of working on it whenever I had time, my model of a Unimog U5000 truck is finally complete. It has the following functions: 4x4 Drive with 2 PF XL motors Steering with PF M motor and linear actuator Remote diff locks, front and back, using pneumatic actuators Remote 2-speed high-torque gearbox BuWizz power More photos on my BrickSafe: https://bricksafe.com/pages/Teo_LEGO_Technic/unimog-trial-truck The whole idea of this model was to build a truck that could both travel at a fairly fast speed as well as work very well offroad, which meant it needed a gearbox. It also meant it needed differential locks so that turns could be taken smoothly at high speed with diffs unlocked, and offroad terrain could be tackled better with diffs locked. The main goal of this model was to create a drive train that wouldn't allow any gear slippage or breaking even under tension in low gear. My solution for this was to use @Sariel's heavy-duty gearbox (http://sariel.pl/2011/02/2-speed-heavy-duty-linear-gearbox/), as well as the new differentials from the 43109 Top Gear car. However even those differentials can't take as much torque as I wanted to put on them, and neither can the universal joints leading to the axles. For this reason, I decided to speed up the transmission before reaching the universal joints and differentials to reduce torque, then slow it back down afterwards between the diffs and the wheels. This would cause a bit of power loss to friction due to the increased number of gears, but it would reduce the torque on the sensitive components and allow me to send more total torque to the wheels. The result is that the 2 powerful XL motors are sped up 5.01 times or 1.8 times (in high and low gear respectively) before reaching the diffs and universal joints, and then slowed down 11.67 times at the wheels. Therefore the final gear ratios in low and high gear are as follows: High gear - 2.33 : 1 Low gear - 6.5 : 1 The result is that the drivetrain is indestructible and never breaks even when run with a BuWizz on ludicrous mode and the wheels come to a standstill. The most complicated part of this build was fitting all of the functionality in the front axle - linear actuator steering placed close to the pivot to increase the range of motion, lots of gear reduction, portal axles, and a differential locking mechanism. Although the result is quite good in my opinion - thanks @Zerobricks for the custom portals - the final construction wasn't as sturdy as I would have liked, and this was the main issue with the final model. The steering has less power than I would have liked with the small actuator, and the custom portal axles bend outwards under pressure when steering over rugged terrain. Overall however I'm quite satisfied with the final result Thanks also to @functionalTechnic for the advice, and to everyone else who contributed to the WIP thread: Enjoy! - Teo

Thanks! And cool Trial Unimog, it is indeed a much smaller scale, but it's quick

Hey guys! Finally the truck is complete, not a lot of time to work on it these days but at last I got it done. Please let me know if you guys see any room for improvement, and if not I'll get to the video hopefully next weekend ;) Here are some quick pics: As you can see, the seats are taken from the LEGO Defender. Unfortunately I had no time to come up with something new.

Thanks! That pic is exactly the look I'm going for, once my parts ship I'll post the finished truck ;)

Hey everyone, I know it's been quite some time since the last update, but here it finally is The general shape of the cabin is done. I just put in an order for parts so the hole in the front and side of the engine cover will be filled when those come. 1x2 black beams will fill in the space on the red hoses to create nice rounded mudguards, and a small pneumatic piston will complete the diff-locking system. After that, the only work left will be to add some seating, a dummy dashboard, and a few more details here and there. It's almost done though!! If you guys have any advice for improvements please let me know. I tried to keep the cabin pretty basic, partly to make the model light and capable, and partly because I want to finish it soon so I can move on to a new project. Here are some pics:

What a gorgeous truck!!

Hey guys, I know it's been some time since the last update, but I've finally had time to put some more work in. The chassis is pretty much completed, I only need to purchase a small pneumatic actuator to finish setting up the front diff lock, but everything is ready to install. I completed the following: Added Panhard rods front and rear to centre axles Modified the position and connections for the suspension to enable smoother travel Installed and secured the battery box and pump with @functionalTechnic's auto-valve assembly I'm really really pleased with the overall performance of the truck. It gets good speed in the high gear and soooo much torque in low gear, with no risk of gear damage due to the clever transmission setup. The diff locks work like a charm, and the steering has plenty of angle as well as plenty of strength despite using a small actuator. My only complaint is that the front portal axles aren't nearly as sturdy as the rear ones, but that's the sacrifice for compactness that I have to make by using @Zerobricks custom portal axles, and they still hold together well enough to function properly (I just would like to see them strong and unbreakable for my own satisfaction). Here are some pics of the chassis: Let me know if you guys want to see a video of the chassis overcoming some obstacles, or if it can wait until the body is finished for a full video. Now it's time to start work on the cabin. I've decided to go with the U5000 look, I love that simple boxy offroad look. Any suggestions for where I can find more pics of that model? Hope you guys like it Let me know any tips for improvement!!

Good point, that’s my hope as well. I’m glad I went to the trouble of changing the driveshaft, it’s a substantial improvement

UPDATE: The main fixes are: Lowered the drivetrain in the chassis to reduce negative caster, and increase space availability (great tip @gyenesvi ) Used the extra space to change the mounting of the M-motor that controls the gearbox to be in the center of the chassis, above the rear axle Another improvement was moving the diagonal beams inward to allow the suspension to attach closer to the body without hitting the chassis, and so make the side-to-side component of the suspension softer for better offroading: Do you guys see any opportunity for improvements? How high should I make the truck rest - higher is better for clearance, but lower is better for toppling over. I will probably stick with the original Unimog design: Done, good catch! Please let me know whatever tips you guys have for improvements! I really want to nail this project, it's coming along really nice

While I'm working on rebuilding the chassis to lower the drivetrain, I also decided to redesign the gearbox. Now the actuator is centred, and this keeps the sliding motor section from getting angled by the previous off-center actuator - this means less friction, and so less power lost:

This is a really cool MOC! I'm excited about the next progress report .

Ohh ok got it. I’ll redesign the chassis then, wish me luck!

Oh ok, that makes sense . What would that improve, the negative camber angle? Because the steering is equally solid with or without the camber angle it seems. It would be a pretty major redesign I wonder if it's worth the trouble... That's a good idea . At the rear, the challenge is that the pneumatic pump gets in the way but I will try to get around it. The other issue on the rear has been that I can't move the diagonal beams any further inward as they will touch the axle, so the suspensions have to be mounted further out than I would like, stiffening the side-to-side movement of the suspension. I will be mounting the suspension closer together on the front however so that the front axle has more side-to-side movement. This is consistent with the LEGO Unimog, and I think it's useful for keeping the vehicle more stable - the heavier front of the car can tip over more easily.

You're right, definitely would be nice to see some better steerable portal axle options from LEGO The entire drivetrain is indeed, as you say, quite high in the build. The reason for this is that, when building the front axle, the only solution I could find to build the front axle to be steered by a linear actuator, powered, and have a pneumatic differential lock system, involved building it with the large ground clearance. After that, I built the rear axle similarly as there was no point in modifying it. Next, I placed the motors lower than the drivetrain in order to reduce the extra ground clearance, which does not match the clearance in a real Unimog, and the extra height would have made the truck fall over easier when climbing over obstacles. Do you think there is a solution for keeping the drivetrain flat, but also avoiding excessive ground clearance? It would require a rebuild of the chassis so far, and although it would reduce the negative camber, the steered axle was causing issues in testing even when placed flat, so I don't know if much would be gained The issue with the rod is the tight space I have to work with. After lots of different iterations, here is the best I could come up with. I just need to brace the shock absorbers better:

Thanks man! Yes, it is getting very large In terms of ground clearance, the photo shows how the suspension will look when it is fully compressed - normally it will be much higher: On the front axle, I didn't mean negative caster I meant camber. As you say, there is no way to get rid of the negative caster - that's part and parcel of the ball joint mount - the issue is that the wheels tilt and sag outwards as the car drives when steering. I can post a photo to show what I mean: I don't think there's much I can do to fix it - implementing Ackerman geometry is too painful, and either way the custom portal hubs aren't as robust as the LEGO ones. On another note I could use some advice - how do you guys think I should mount the axles? My initial plan was to use Panhard rods, but even with the long linkage (below), there is quite a bit of side-to-side movement due to the long suspension travel, and the fact that Panhard rods naturally inscribe an arc. Should I use a different centring method? Like in the 9398 Rock Crawler?

Hey guys, it's been a long time since I had time to work on this project, I was just too busy with school. But with the semester over, it's finally time for an update: The gearbox is installed in the chasses and the beginnings of the chassis are started, complete with strong bracing and diagonal beams. The M-motor for actuating the gearbox is installed, as well as the M-motor that drives the pneumatic pump and auto-valve (based on @functionalTechnic's design here). The job now is to install the suspension mounts to the chassis, and to position the Panhard rods that center the axles. An issue I've found is that the wheels on the front axle start to develop an unwanted negative camber angle when the car drives with the steering all the way to one side. This may be because the tires on the front aren't braced as strongly as on the rear (due to the custom-made portal axles), or maybe it is due to the lack of Ackerman steering geometry (the wheels pivot equally when steering). It's not a very serious issue, but I would like to be able to resolve it. Otherwise, a preliminary test worked like a charm. The truck gains pretty decent speed on high gear, and has a ton of torque on low gear, without any gear slippage happening or other issues. It's just so great to have time to work on this project again after so much time!

What an amazing build! I can't believe how many functions are packed into that tiny scale!

UPDATE: Finished bracing the front axle: Built the rear axle, similarly to the front but much sturdier since it doesn't have to be steered: And here's the beginning of the gearbox. Design uses Sariel's principle (http://sariel.pl/2011/02/2-speed-heavy-duty-linear-gearbox/) but with 2 XL's. Final gear ratios from the gearbox outputs are: 1. 1:5.00 2. 1:1.80 This ensure that even in the slow gear, only the torque of 1.11 XL motors is driving the front and rear diffs, and so no gear damage will occur. The slowing down at the wheels will be: 1. 2.33: 1 2. 6.48:1 This gives it more than enough torque on the low gear, and quite good speed in high gear. Thoughts? :)))

Hey guys, sorry for the long break I took from this MOC, but school has been very busy. Silly real life priorities kept me busy But back at it! My choice right now is about what wheel-base to use: normal or long. The image below shows both: I have to figure out how to fit in the heavy-duty gearbox as well. My thoughts are that the long base gives me more room and more climbing ability, but the added weight may reduce performance, and the small actuator used for steering may start to run out of power. The smaller base will be lighter, but requires a more compact design, and also won't climb as steep slopes. Thoughts? Let me know guys, I'm going to get back to building now I have more free time!

Thanks! Bouncy was what I was going for :)) Fair enough, I was going for something like these: I used RM8's setup from his Sunset Baja Truck. Unfortunately, your're right, at this scale the buggy motor has to take up cabin space. That's a good point, I didn't try removing the diff. It probably would slow it down a bit cornering on smooth surfaces, but offroad would probably help. I'll try that next time

Brilliant idea! Maybe I'll make use of that myself someday, and give credit of course :))