HorcikDesigns Posted January 24 Posted January 24 (edited) Warning - following article depicts a use of extensive number of non-LEGO elements (custom 3D printed parts, Aliexpress parts, RC components, painted and cut LEGO bricks, which together are still less than approx. 10% of total MOC weight (not counting motors and water tank)). They are used only there, where no suitable LEGO alternative was available. Hello, I have a quite a long story about a Firetuck MOC. It is a follow up of my 2 years old topic, which I decieded not to revive. Well, if you are interested, here is the full story. Long time ago, for some of you not that far away, (ok, to be specific - January 2024, central Europe), one man (me) has decieded that his AFOL journey will not be complete without large scale 6x6 firetruck. … (switching to first person) So, if I remember correctly, it started with and old prototype of Tatra trial truck chassis with one central driveshaft, and Control+ motors with mounted 3rd party 82mm tires for 1:14 trucks, and the rest you can find in the old topic. Big plans, but as a first generation of a MOC built in slight hurry, it had some flaws. You can see that in this stage it looks more like TATRA offroad vehicle than Airport firetruck. Well, by this time it was still more Tatra than anything else. It has one interesting feature, due to chassis construction which has wheels offset by 1 stud, the construction of mudguards is also offset by 1 stud when comparing left and right - which led to some issues with build symmetry. It also had easy access to batteries and working rolling doors on sides. You can also see different approach to arm construction. Well, then I visited an Technic themed exhibition in Germany (Technic Welt Leipzig 2024), met new people, seen some awesome and also famous Technic MOCs, and after testing the sluggishly slow chassis on the exhibition track, I decieded I need new and better performing chassis for my new MOC. You can see Instagram videos and some photos from that event in the window below: Spoiler https://www.instagram.com/horcikdesigns/reel/C7y_BFVIi-O/ https://www.instagram.com/horcikdesigns/reel/C70sJmQojQh/ shoutout to Huwi's Truckstop and Efferman's recovery truck ____________________________ GEN 2 So after I got back home, I started with second iteration. I have decieded that I will go slightly heretic way with more 3D printed parts and 3rd party brick compatible RC controllers. Two MK 6channel bricks covered planned 12 channels well. The functions were – All wheel drive, 2 axle steering, 2 speed transmission, front water gun operation (2CH), top arm operation (5ch) and 2 pumps. More on that later. chassis detail, where you can see 3D printed parts and differential that connects left and right side. Well, this drivetrain was not used in later versions, altough the central differential and dual driveshaft stays. Halfaxles do not rotate around the driveshaft, so there is no additional load to the drivetrain from the weight of the vehicle. Spoiler Rear axle steering detail. Area above front axle was very tightly packed, with working steering wheel, water gun rotation and elevation, and working steering and suspension Front axle steering Again, Instagram videos if you want to see the WIP truck in action Spoiler https://www.instagram.com/horcikdesigns/reel/C92DhKFIVfb/ https://www.instagram.com/horcikdesigns/reel/C92AneNo-6c/ What the MK battery boxes were not good for, were two buggy motors or a custom motor I have built some time ago. They all drained the battery very quickly and the contacts did not liked it either. Unfortunatelly, I figured it out too late, there was no time to improve and rebuild it before next exhibition of my local LUG. You could see both generations side by side on that event. Spoiler All my firetrucks at that time on display (in front you can see my TC entry) By that time I also started researching ways to build custom Remote controller from Arduino and game controller joysticks to control all functions of the truck more comfortably, or investing into more advanced remote controller. Well, I can tell you that there are some detailed instructioons, but I have decieded to not build or buy that, and made „a very unique solution“ instead. More on this later. Instead of the remote, I spent the time designing the fire fighting water gun arm and making it to work well enough - that means smoothly and quickly. I wanted it to have quite vast reach, telescopic section and positionable water canon at the end. This part was kept unchanged for next iterations of the truck. Here you can see the arm that survived to the current version. there was one version that used ropes to move the telescopic boom, but it was not reliable enough, so traditional rack and pinion is used here. Also with custom built 3D printed micromotor. Spoiler detail of testing different headlights during the GEN2 build process. still, the truck is more offroad truck than Airport truck. The rear section was just empty shell to hide cables and empty space left for furure water tank. Well, then 2025 hit me hard with other non-LEGO related tasks, and the firetruck was left resting. I knew it had to be redesigned, its 2 speed transmission does not work well (due to gear meshing issues it was capable of only going backward), and I was not in the mood to deep dive into that MOC that time. While the MOC was collecting dust on WIP shelf, I slowly started collecting neon yellow parts for the next big plan. _______________________ GEN 3 (chassis GEN2.1) Sometimes around 10/2025 I woke up, picked the truck from the shelf and started disassembling the body that I was not satisfied with. It did not make practical sense to me at that time. After that I did some quick sketches, researched images of Airport crash tenders (like Rosenbauer Panther and similar) and Tatra trucks (I still had parts of working chassis for a Tatra truck), and while doing that and putting drawers with stored neon yellow bricks on my desk, I found my 3D printed Brushless motor reduction gearbox and unused brushed motor. Well, this one I could not power with the MK 6CH remote. So another reduction was made, and the motor was built into the chassis. I ditched the 2 speed transmission as I wanted the MOC to be reliable for exhibitions, so the current version has only single speed – It is electric, so it does not necessarily need it after all. And it is too heavy so I guess I will never make it go offroad. But, who knows. The chassis has 2 differentials - one on front axle, one for rear axles - this time it works as it should. After calling the chassis ready (not finished) I could start with the GEN3 body. Firstly, I kept the front bumper that I liked and tried to build can on it. Well, it was short, high, ugly. It was not working either - just judge by yourself. GEN 4 (chassis GEN2.4) After that, I finally decieded to choose the way of Panther-like concept (on Tatra chassis) to keep me unconstrained with the design, and I could have started with the (currently) final iteration. Here you can see my fire-dummy built to scale, and below some moments from build process https://www.instagram.com/horcikdesigns/p/DSxtntzDF4N/ (link to IG post with sketches on the end) Spoiler Testing new gen of rolling door before painting and fitted pumps. Arm rotation mechanism with Geekservo motor (saving space and ESC, the geekservo motor is powered directly from reciever ) Arm mounting to the undercarriage - springs help with the first stage elevation from horizontal position. Wires on the right side of the photo are mostly for LEDs Well, since then the build was straightforward (more or less, like typical MOC development). Funny moment was ordering 20, 30 and then finally 50 2x2 trangular tiles. Hope now I am finally well stocked. Shaping of the door strongly rely on friction between bricks. The trans clear windows are already replaced with trans brown ones that fit the dark cab theme more. Opened and closed side compartments, after painting. They are used to hide not tools but electronic wires. Hope that one day I will find a way to clean it up and do proper wiring and use the compartments to hide some useless but aesthetically pleasing brickbuilt fire fighting equipment. Spoiler Testing of LEDs. And here it is in its current state. Panelling nearly done, wiring messy, but done, water system ready to shower random visitors (just kidding - they will not be random, only those who will ask will see it in action - firsthand) Flashing lights video: https://www.instagram.com/horcikdesigns/p/DTvxT7mjMjq/?img_index=2 All photos: https://bricksafe.com/pages/horcikdesigns/airport-crash-tender/wip-photos IG stories (development diary): https://www.instagram.com/stories/highlights/18291669121088051/ Spoiler Back to the Remote controller story line – I decieded that for the arm and front water gun operation was the joystick MK remote controller just fine, but for steering and drive I needed better solution. So I have checked what I had available, considered building custom remote for the last time and started my CAD. The result? The Austar-to-MouldKing 3D printed adapter Turbo 2000! Two budget fiendly remotes joined together to control a bunch of overpriced bricks. Arm and front turret is controlled by the MK remote; arm rotation, drive, steering, pumps and some lights are controlled by the RC transmitter. Beacon lights use another 3rd party solution which is powered from the MK battery box (or from external power source on exhibitions) _______________________________ Well, here we are in the present days. The water tank is mounted, the hoses connected, lights flashing, and I need to finish the panelling, and make a video of this long-term project. So, what do you think? Which generation do you like the most? What can I improve or completely scratch? Which part do you want to see in more detail? Edited January 24 by HorcikDesigns Quote
2GodBDGlory Posted January 24 Posted January 24 Nice work, and thanks for the detailed writeup! I think all the generations look great--you've got really good use of colors and shaping on them! Quote
HorcikDesigns Posted January 28 Author Posted January 28 @2GodBDGlory Thanks for the feedback. :D Quote
m00se Posted January 29 Posted January 29 On 1/24/2026 at 1:29 PM, HorcikDesigns said: What is that massive thing on the back? Quote
HorcikDesigns Posted January 29 Author Posted January 29 @m00se That is my custom 3D printed watertank, volume approx. 400ml. Quote
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