Mechbuilds

I wish they would sell an RC type servo that was converted to work with buwizz using those lego connectors. The servo could have a frame of their own around the servo so it's easy to connect to technic. The lego servo is garbage.

Not a single image is working.

For anyone who is encountering this error from time to time. There is a fix. All you need is VPN. For me i was getting this error constantly and couldn't get here. But then i used VPN and changed my server to germany and poof it worked like magic. Have no idea what caused it. And it seems to have fixed itself since now i'm not using VPN and can use the site just fine. But for next time, i'll have VPN ready.

Yeah i think the force of the gear meshing with the wormgear trying to push it will stall the motor. Good idea in paper but bad in practise.

Interesting solution! You can also have a fake engine spin while it's on neutral.

Very nice job! So compact and clever use of that shoulder pad as a chair.

Interesting mechanism to auto lock. Very nice build! Very ingenious solution on the front suspension.

Oh.. I guess it's never been done before.

Anyone know a compact gearbox that uses XL motor to have 2 imputs: Worm gear drive for crawling and regular 1:1 with no wormgear for drive? That way you'd have fast moving gear for driving around and then use worm gear for crawling. Why? Because worm gear is pretty much instant brakes once you let off the throttle.

Oooohh.. So the blue pins are there for no reason?

Gotta love that tube frame chassis. And the easily detachable body! Nice work!

For some reason when i make the hood, the hood connection will hit the bumper connection. I just don't get it.. I'm planning on making this with a turn table on the rear so it will have a springless suspension. Can't figure out any possible way to fit a suspension on this chassis. EDIT: I mean suspension for the front axle.

There are many issues with the instructions. But the hood is pretty much impossible. In real life, it will hit the bumper support and it's one stud too low. I'm currently using the same chassis to build an articulated dumper. Very easy to convert the rear.. I'm trying to make the front end completely out of lego since i don't have many system parts.

It's so well done that you'll have to look twice to realize it really is lego.

@grego18f's 6 cylinder diesel: Works great and had good details.

Instructions on the trucks would be cool too! They look pretty good!

This is one way i thought about doing the steering system.. Anyone else got any better solutions in mind? I can give the LDD if anyone wants trough PM. EDIT: After building it physically, yep doesn't work either..

The issue is geometry. If i have the steering link attached to the top, the steering link would need to compress as the suspension moves. I need to move the steering arm lower so it's at the same height as the pivot point that lets the tyre rotate up and down. But the issue with that is that the whole axle assembly will hit it. So i would need to make the steering arm much much longer so it clears the assembly. When i do that, the steering arm is very far from the wheel itself. So i'll have to use ackerman geometry. But when doing that, the 5 long steering ball cup arm is too close to the center.. There are soooo many variables with it. That's why making functional steering for tatra axles is extremely difficult. If the geometry is even slightly off, the wheels will steer as they move up and down from the suspension.

I've made thing physically irl. There is an issue on the gears skipping teeth.. So i made out a quick sketch up in LDD for two different mechanisms that allow you to have tatra swing axles without the axle riding the driveshaft: Both of these have issues. The U joint one is not as durable but it's much simpler to make with less parts. The gear version is much more complicated but much sturdier. I wonder if there are other solutions to this? I wonder which one i should go for? This type of axle can't be made for tank steering i think. I just can't fit two drive shafts in the middle without making the thing extremely wide. It's already very wide as it is. So using the 7 wide beam in the middle is the maximum width i can give this. (preferably i'd do 5 wide in the middle but there simply is no room.) As for using the 5 long steering arms, i didn't really think of using those. It could quite possibly work! Just need to figure out a little bit more complicated steering rack assembly but worth the shot. EDIT: Third option gives me half a stud more room in the middle.

Can anyone figure out a steering mechanism for this? The axles work for two driveshafts and they will not hang from the axle but instead be braced on the frame. This way you get less stress on the motors and a much smoother ride. My plan is to attach both XL motors to the two drive shafts and have a gearbox that switches from forward to backward into turn left or right tank steer. If i have just regular tank steer system that both drive shafts are individual then both motors will probably turn different speeds and it will steer constantly. EDIT: After some testing, i've come to the conclusion. that the hinge will cause some gears clicking.. Also the steering ball joint needs to be at the point of the hinge.. I think i'll fix the gearing issue by putting a U joint at the point of the hinge. That way i'll have the iconic tatra style swing axle suspension but have none of the gear issues and no riding the drive shaft. But this also means that the whole build will be 2 studs wider. but i can also use a differential in the middle if i want to.

Awesome! I'll keep an eye on your build thread!

Here is my try: Obviously it needs 2 drive shafts. But everything seems to work. you'll just need to imagine the center be 5 studs instead of 3. But steering is another ballgame to make it work.. EDIT: I just realized that if i use two XL driven driveshafts.. I can get tank turning on this. (by powering both axles in different direction by using the XL motors.) Basically, you couldn't get this thing stuck anywhere. Forward and backward, tank turning, 4 wheel steering, (possibly even crab steering if a gearbox is used for the servo.) And ofc iconic tatra swing axle suspension. How are you guys NOT exited?

Those shorter parts, i only have 2 of them.. Really don't have the cash this month to put up a new order no matter how cheap the parts are As for how wide? I'd be using claas tyres. So width is pretty much what looks okay for a 4x4.. I'll build the model around the axles.. I'm always going for durability over looks. I like the chassis beefy and strong. I wonder if it's possible to have it 4 wheel steer. But since the wheels are so far apart in a 4x4 version, i'd probably have to use two servos to make it work.. That or a very very long axle and put the servo in the middle.

Can this tatra axle be made without this part: (i don't have any of these) Also smaller 20t gears in the middle since i only have 2 of those larger bewel gears. I'm planning on a 4x4 tatra and i like the idea of the axles not stressing the driveshaft. Steering is also a whole can of worms. All tatra mocs are mostly 8x8 and have their own special suspension and steering system.

Details on the engine are beautiful!