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I don't usually post my work projects here, but every so often there is a special one that I really want to showcase more in detail. Today I want to show you one of my all-time favourite projects, which is packed both full of functionality and a very high level of detail. Before we go into the details, lets' first let's talk about the idea behind it. We (the BuWizz team) have been cooperating with Slovenian AMZS (Slovenian Automobile Association) for a while now and they are the ones who allow us to record the various speed breaking and such events on their polygon. An idea emerged for a project to design and loose replica of their existing Tow Truck which is to be used for education purposes. Here's how one of their tow truck looks like: I decided to use this specific model as an inspiration of my representation and here were the basic starting functions and features: 1:10 scale Capable of lifting and towing an actual 1:10 model like 42125 All Wheel drive Working gearbox Realistic suspension Highly detailed As with most of my projects, i first started working in LDD and this is what the first prototype looked like: I took some liberty with the shape, notably I removed the crew compartment in order to better the lift arm details. As the project progressed, so did the amount of functions, features and details until I ended up with this long list: Motorized with 11 motors Powered by 2 BuWizz 3.0 Pro bricks All wheel drive powered by 4 BuWizz motors Working gearbox with a high and low gear 3 differential locks Independent suspension in the front Solid rear axle in the back which uses 3x13 curved panels as leaf springs Working V8 engine connected to the drive motors Functioning steering wheel linked to the steering rack Motorized lift which can unfold, raise and lock onto thr wheels of the towed vehicle A motorized winch in the rear Working front LED lights Opening doors, hood and compartments Detailed engine bay with battery, air filter and washer fluid Compartments filled with details such as fuel canisters and various tools Other details include cones and fire extinguishers 3D printed braking discs in the front for show Total piece count is around 3060 parts Just over 3 kilograms 51 cm x 24 cm x 22 cm when folded excluding mirrors Capable of lifting and towing a 1:10 scale car like 42125 even up a steep hill Top speed of 10 km/h Here's an overview of the model and the basic mechanical functions: Driveline is powered by 4 BuWizz motors. The motors drive a 2 speed gearbox and a fake V8 engine: Gearbox is powered by a PU M motor and uses 2 mini linear actuators to switch between low, neutral and high gear: Each of the 3 differentials has it's own lock, actuated by a wave selector and powered by a PU M motor: Steering system is powered by a PU L motor and uses two steering racks in order to both steer the wheels and turn the steering wheel: Finally, there are several more PU M motors used to power the rear arm. The main actuators lift the whole arm and are powered by 1 PU M motor: Another PU M motor is used to unfold the lower part of the lift arm using 2 mini linear actuators: Finally another PU L motor is used to lock the wheels with two more mini linear actuators. The driveline is designed in such way that the arm can swing a bit while cornering: The lifting arm had to be designed to be as strong as possible, yet thin enough to slide under the car we want to tow. The final version was under 2 studs high and capable of lifting a 2 kilogram heavy model with ease: With all the details finalized and the parts omptimized in the LDD version, it was time to build the real deal: As mentioned above, the model is full of details that can be accessed by opening the various compartments: The rear view showing the folded tow arm and the 2 large actuators used to lift it: Few more pictures of the model next to the real deal: Of course no Technic photoshoot wouldn't be complete with the most important photo of them all, the underside: The underside was left open and exposed intentionally, so that the gearbox, the differential locks and steering system can be observed. Of course as with all the projects, this one also had some issues, the biggest being the use of 3x11 curved panels as the rear leaf springs. Originally only a single pair was used to support the weight in the rear and the additional load of a towing vehicle, but it soon proved too much for them and over time they ended up breaking. That is why for the final fix, they were doubled, to increase the stiffness and durabilty of the rear axle: Other than this, there were no other major issues with the model. The driveline has yet to skip a gear, the joints are holding (even the small CV joint used in the front left side) and the model ended up being robust enough for some really rough driving. As mentioned at the start of the topic, this is one of my best models to date, I'm really happy with the amount of sheer functionality, features and details I managed to cram in it and it will forever hold a special place in my heart. To wrap up this already long topic, here's a couple of videos of it in action:

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

A compact sequential heavy-duty 4 speed remote controlled AWD gearbox Each gear of this remote controlled gearbox approximately doubles the speed of the previous. The output shaft contains an integrated lockable differential for AWD. See the video for a WORKING DEMO | FREE INSTRUCTIONS below. GEAR RATIOS 1st 6:1 2nd 3.3:1 3rd 1.8:1 4th 1:1 FEATURES compact remote controllable sequential gearbox 4 transmission speeds evenly distributed gear ratios differential output (AWD) differential lock single rotary catch many mounting points no half studs INSTRUCTIONS [PDF] https://bricksafe.com/files/hdegroot/remote-controlled-4-speed-awd-gearbox---with-perfect-gear-ratios/remote-controlled-4speed-awd-gearbox-with-differential-lock.pdf [3D MODEL] https://bricksafe.com/files/hdegroot/remote-controlled-4-speed-awd-gearbox---with-perfect-gear-ratios/remote-controlled-4speed-awd-gearbox-with-differential-lock.io REBRICKABLE: https://rebrickable.com/mocs/MOC-83457/hdegroot/remote-controlled-4-speed-awd-gearbox-with-perfect-gear-ratios BRICKLINK: https://www.bricklink.com/v3/studio/design.page?idModel=244834

There is one thing which has a great influence on off-roading performance, that is differential. Open diffs will severely cripple off-roading capability of a vehicle, but without a diff, turing radius is going to be awful. Can you really balance the two? I’m showing you two new MOCs regarding this topic: a Land Rover Defender & a monster truck. (There will be two new official LEGO sets which happens to be a Defender and a monster truck, I think this is pure coincidence...) 1. Land Rover Defender I have never tried building a model with no differentials. So maybe I should give it a try to see how it performs. The drivetrain is pretty straight forward: Then I started adding details to it. I was expecting it to be a lightweight model, but when it seems aesthetically acceptable to me, the final weight (1.3kg) is beyond my expectation (around 1kg). Other than that, the actual turing radius is really bad, something I can’t take. So Let’s not talk about performance, just take a look at some details: I have to say this MOC is not too sucessful, so I didn’t bother making a video for it. Even it is fully remote-controlled, to me it is still a display set. 2. Monster Truck So how can we really get maximum performance without losing the benefit of differential while cornering? Most of us know the answer: diff lock. We’ve seen so many great builds with manually or remotely controlled diff locks, and I want to make something different. Then I came up with an idea: Can I design an automatic diff lock, which locks when the vehicle goes in a straight line, and unlocks when it takes a turn? Of course in many cases the vehicle also needs that diff lock to be locked when it takes a turn, but considering it’s a fully automatic action without an extra motor to control the lock, This is an acceptable trade-off. Besides, other factors could somehow compensate for that, like grippy tires, responsive suspensions, etc. I soon realized that this is not going to be a tough job. I only need a simple mechanism that somehow links the diff lock to the steering motor (Servo motor). A video (4K) to show it all: The concept of this MOC came from Monster Jam trucks, that’s why it has roll cage and detachable body. The chassis and axles is no way near a real monster truck, it is built solely for the purpose of demonstrating the auto diff lock. And I think it performs great and seems reliable enough. Hope you like these two MOCs!

I decided to UP the things with my take on the 8081 modification contest. Here's what I came up with: Driven and steered front axle with homeage to the original design Tandem live rear axles working on a simillar prnicipal as the front axle Differential lock Two speed gearbox Working steering wheel You can see a sneak peek of the progress made in LDD:

Hi, I am presenting you my latest MOC – a mega monster, which I would gladly have it parked in my backyard (I would of course need a large backyard first) - MAN M1001! Since this creation was being built during a lot of night shifts since the end of March 2013 until the end of July 2014, me and this beast are almost in a kind of relationship and through that year and a half I have hated it and loved it again, almost left it, but returned to it... Now, as this saga of mine is soon to end (recycling), I'll indulge myself a little and also write something about the real truck and some creative adventures I've had building. I also want to present the MOC with a bit more photos, I hope it is OK, I haven't found any limit regarding number of photos in a post. If there is some violation, I'll gladly make it right. Those of you, who are not so much into reading, I suggest you just skip it and proceed to photos – no hard feelings. MAN M1001 / M1002 / M1013 / M1014 I haven't found extremely much data on the web. There is a lot more on younger M1001 relatives KAT I and KAT II. A summary of the data obtained is as follows: Those trucks' production started in the early eighties in Germany in the factory MAN AG for the needs of American armed forces and have been designed as a tactical 10-ton tractor units for transport and supply of tactical missiles Pershing II (MGM-31C) and Gryphon GLCM (BGM-109G). Through several versions and successors the MAN 100x series proved to be one of the best off-road tactical vehicles around the world. According to some data, it should not have any problems with fording up to 120 cm water, climbing slopes of up to 60%, sideways driving on slopes up to 40%, overcoming the 1.9 meter trench and overcoming step to a height of 0.6 m (depending on tire size and undercarriage configurations). American forces have used four versions of the basic truck that is powered by 400 horse (several data) V10 turbo-diesel. All versions are built on extremely torsion-resistant box section framework 8x8 chassis with steered front two axles. All axles are rigid "live" axle with rubber mounted springs and large shock absorbers. Basic models are the M1001 - a tractor with a crane, winch and even 30 kW power generator and the M1002 - "tow truck" or a wrecker with a crane, a small flatbed and a carrier for a bunch of spare tires. A little younger models are the M1013 which had a crane in addition to an even bigger flatbed, and the M1014 which is plain flatbed truck. All, except the M1002, which is longer due to towing equipment, are 8.57 m long , 2.5 m wide and only 2.75 m high (cab and lift), 2.85 m (spare tire) and 3.1 m (the generator). Sources: http://olive-drab.co...tos_man_8x8.php http://man.army-uk.c...quip.php?ID=333 http://www.truckspla...odel.php?id=646 http://heavycherry.c..._tarpaulin.html At the beginning of my research and modeling, I came across information somewhere (currently I cannot find the source), that the investors (U.S. armed forces) demanded the trucks to be low enough that they can be transported by rail. It is from this demand the trucks got the recognizable cab with trimmed top edges, so the loaded trains remained in the characteristic profile of the rail. With this same purpose the engine is not mounted under the cab, but behind and partially in the cab between the two seats. MAN M-MajklSpajkl Those of you who dug a little through the source pages of the above given description of the real trucks, have probably quickly noticed, that my MOC is actually neither one of the types described - it's a hybrid. At the beginning I fell in love with the M1001, I liked it’s silhouette by far the most and began modeling , but later I found out that because my axle design, the chassis came too high and that it does not look too good as a tractor - so therefore I camouflaged the chassis with a flatbed and of course the obligatory crane. I designed the flatbed and the crane without leaning to the actual models and therefore got a little strange formation of the crane and the outriggers. I tried to replicate the crane as closely as possible though. Modeling process began by obtaining blueprints and photo-material of the M1001 and scaling it to the size of 9398 4x4 Crawler tires. Scaling to these tires produced an approximately 1:14 scale, which already shows the size – but hey, building big was the main idea! In addition to the cross-sectional blueprint of the rear I also used an "en face" photo printed out in scale, so it was much easier to model the characteristic front of the truck. You are to judge, how I pulled it off. I must say that my MAN is not nearly as technically superior as I have described its big brothers above and that it is a beast only if you use a little imagination or see it on photos… I'll soon tell you why. But first,... 1. MOC DATA: Length: 79 studs overall (63.2 cm) – I had to lengthen the chassis for 2 studs due to drive train Width: 23 studs (18.4 cm) + rearview mirrors max. 4.5 studs on each side Height: 25 studs (20 cm - top of the cab without air vents), 31 studs (24.8 cm - top of the folded crane) Weight: 3680 g (truck) + 280 g (crane) + 640 g (4 power generator (cargo) only one with six AA batteries) = 4.6 kg Part count: ALOT! I will provide exact number when I disassemble it, I'm guessing about 3000-4000 pieces - update: after painfull disassembly I counted 4404 parts. Motorized functions: - 8x8 propulsion (reduction from the engine to the wheels 1:21 in 1st gear and 1: 12.6 in 2nd) - Front two axles are steered in first/second ratio 1:0.67 + working steering wheel - Two speed gearbox (1 - 1:1667, 2 - 1:1) - Differentials lock on axles 3 and 4 - Working windshield wipers - Automatic pneumatic valve for lowering / raising the outriggers Other features and details that I would like to highlight: - Rigid full-sprung axles (live axle) - three point hitch - PF LED headlights, on/off via the PF pole reverser - Opening cab door - Adjustable rearview and side view mirrors - Manually pulled out outriggers - Separately opening sides and rear of the flatbed - "Access" to the gearbox via a door in the bottom of the flatbed - Access to the imaginary controls for pneumatic or. "Hydraulic" pump through the side door on the flatbed - Access to power switch for the front light through the side door on the flatbed - Spare tire - Illustration of the engine behind the cab - Manually "driven" crane Atlas 4300 M5 with a double pull-out arm and winch - "Rich" dashboard - Seats and shifting stick in the cab - Protective grids for front and rear - Cargo – power generators (the idea was born out of a major sleet storm in our country past winter) - I must have forgotten something... PF components used: - 2 x XL motor for propulsion (engine coupled with the so-called "adder" differential) - 1 x L motor for steering - 4 x M motors (auto-valve, gearbox, differentials lock, wipers) - 2 x PF switch (on / off lights, pole reverser on one of the XL motors) - 1 x PF led lights in front - 3 x IR receiver (v2 drive and wipers, 2x the ordinary for the rest) - 4 x large BB (one for power, three for lipstick – power generators) - 1 x IR Speed Remote control (drive and wipers) - 2 x IR remote control (the rest of the motorized functions) - 1 x PF extension wire 20 cm - 2 x PF extension wire 50 cm And now some photos to take a breath during such a heavy reading… Looking mean… Ready to unload… The crane stood relatively well to the loads applied, due to much bending I have only tried it with the empty generators. High loads (kids) led to the main two LA snapping of the pins, since they were not transversally braced. Atlas 4300 M5 crane Flatbed with lowered and removed sides… The generators… I find them quite cute, so the lineup was necessary. For those who have yet to read themselves out of breath, I would have a little description of the "guts" of this birdie. Bare naked chassis (more or less) for starters: 2. CHASSIS AND BODY The truck was meant to be modeled as realistically as possible and so I decided for the chassis of two main studfull beams, which were laterally connected in a fairly robust box-section frame by the 5x7 technic frames. The beams were changed countless times, because in the course of construction a need for holes exactly where they were not would came up, or there were certain parts in the way, etc. The cabin is built from a combination of studfull and studless technic bricks, and even some sytem bricks were used for better looks. All other parts of the truck are in "full studless" technique, with some little system bricks add-ons. 3. AXLES and DIFFERENCIALS LOCKS As soon as I had the idea for a 8x8 truck, along came the idea of planetary reduction within wheels. There are very good solutions for this kind of reduction within the "large racing" wheels (ZBLJ), for "medium racing" I found none, well at least not such that would ensure that the technic turntable is as close to the wheel as possible. I thought of a solution shown below, which looks good, but has the disadvantage that it is necessary to attach the wheel to the turntable before attaching the turntable to the axle. The wheel is attached to the freely rotating 4L axle with stop, so it must be pushed next to the turntable well and in such a way that small technic bush and the free end of 2L red axle are caught between two spokes of the wheel. Of course, the wheel must be turned with the spokes inside. It was a little easier to push the wheel into place when I got some new axles 5L with stop... I find this kind of reduction very interesting, but it creates a lot of friction, which is fatal as you'll read further on. The trucks' axles were the first parts designed and they too, like the chassis, have seen many, to many variations. Back then, when I was designing the axles, I only had enough of the "new" bewel differentials. Locking those is a little more volume-consuming, and therefore such a fat boy for the axis, which you can see below. Differential is actually locked by locking a "by-pass" axis. Because I undertook this for the first time and because I spent all 9L links I had on suspension, it was a real hassle to find a solution for remote locking differentials. I figured out some kind of lever solution, where the mechanism mounted on the chassis practically just hugs a small lever on the individual truck axle. In such way both of the non-steered axles' differentials are synchronously locked. Unfortunately, the system worked well for the locking, while the unlocking of the rear axle was very hard or almost never unlocked -I blame the designer! On the photo below, you can see the transmission from the motor to the double "fork" from the bottom side of the truck and the »fork« hugging the lever in the detail in the lower right corner of the photo. 4. PROPULSION This is more or less a sad story - maybe mix of bad decisions and inexperience. Yeah, THAT THING WON'T DRIVE! As you will see in the video I’m preparing, it only works in the "air" mode. The reason? This colossus is heavy as ... and my enlightenment has insisted on feeding drive to all four axles from a single source. Imagine now half a meter long technic spindle full of universal joints and to ensure easy win, use two CV joints directly on the power source. Those babies sure can take some torque - NOT! Add another bunch of gear in each axis and in each wheel and you get a CV joint without the »joint« part. Anyway ... noted, written in the black books of things not to do! After many attempts, I decided to leave the matter as it will; it should be as an example for the future. 5. STEERING Again, things could not be much worse here, well I suppose it could fall apart completely. However, I like the concept that I tried to put to work very much, so it was again left to be represented in the "air" variant: Proposed design does not use the usual steering rack, but a system of levers, a bit closer to the real 4 axle truck steering system. One wheel hub is pushed forward and backward and this hub is linked to its own pair to the other side of the axis by a rod. The theory is, of course, one thing, and the reality is another. Please find below a display of described system, first the mechanism on the left side of the chassis where the motor is. The worm screws drive two lateral axles and steering wheel in the cab for which I've succeeded quite an interesting transfer with simultaneous reduction 1:8 of L motor speed (see the detail). Each of the transverse axis has a different reduction of rotation, so as to ensure a smaller turning of axis no.2 against axis no.1. Thus, the reduced rotation drives the levers, which steer the wheels. For this reduction, there is quite a simple calculation using geometry - for my MAN it should be 1:0,73. I spent some time looking for the most ideal relationship between the technic gears, but then again, a compromise, and I installed the ratio of 67% (1 - 12/24; 2 - 12/36), which is not very far off. The system, unfortunately, did not work under the weight of the cab and there was too much backlash in all these levers. In order to alleviate the matter, I connected the levers with technic friction pins, hence the axis are a bit jumpy when "air" steering due to overcoming the friction in pins. I know, I should change back to frictionless pins for »air« steering presentation, but… hmnjah… 6. WINDSHIELD WIPERS Motorized windshield wipers are one of the cutest and reliable functions of this little toddler, especially since they're controlled via the IR Speed remote control and thus can adapt to the amount of rain. It is a simple version of the system that drives wheels on steam locomotives - the rotation transferred to the oscillation. It only bothers me, that I somehow didn't manage to get the motor that drives the wipers somewhere in the bottom of the cabin and therefore there is a driving axle between the seats leading to the motor behind the cab, which is to me quite a fine mockup for the real engine. The reason that there is no room under the cab is in the fact that the main beams of the chassis stretch quite deep into the cab and that the suspension of the front axle is attached just below the seats. 7. AUTOMATIC PNEUMATIC VALVE and CRANE OUTRIGGERS When I was almost finished with the truck, there was only one free PF function left and the crane outriggers were missing. There was practically no space left, except behind the spare tire. Luckily, I managed to squeeze in there a modified version of the automatic pneumatic valve by My version is just geometrical adaptation to the space that was available and I think I succeeded well. For those who may not know (not many here I guess): automatic pneumatic valve (there is quite a handful of different types from several inventive authors on the web btw.) is a pneumatic valve with only one motor powering a pneumatic pump and switching the lever of the pneumatic valve at the same time. I had quite some difficulties and I spent some time looking for the right combination to attach the valve softly enough to work as it should. If it was too stiff, it would not change the valves position when changing the motors direction. From left to right you can see a pneumatic pump, driving PF M motor and worm with a pneumatic valve on the photo below. The solution for the outriggers manual extension is IMHO really a small piece of art. Well, a good idea at least. They’re mounted in 5x7 technic frames, through which two axles slide and are protected from falling out by a connector. Since the pneumatic tubes pushed the outriggers outside, I made a "lock" to hold them in place. Loading capacity of the outriggers is of course purely symbolic. CLOSURE, FINALLY And now to conclusion: I'm tired, and not of writing so much of my bad English. I will not start on such a vast (at least to me) and long lasting project for some time, if ever again. I'm really happy that I can finally fully present this MOC to you and I am pleased also that I insisted until it was finished, even though not completely succeeded, but managed to learn a lot of new in terms of design and construction of such a model. I am pleased with the level of small details, which I think for me is increasingly important for a MOC to have. Thanks to all who survived this long writing, as well as the rest of you who just looked at photos and grimacing at the amount of the text. No hard feelings, eh? For those curious, find at this link a number of additional photos, including some of those during the construction, which I didn’t include in the presentation. Best regards, here is another photo of my third child to conclude. Miha And finally - a video: