March 2024 48-hour MOC Challenge Entry/WIP Topic

[2GodBDGlory]

Welcome to the first Eurobricks 48-hour MOC challenge!

After rolling a virtual die to choose between the six options on our list, the official selection for our topic is:

A Vehicle with at least Three Axles!

As mentioned before, this challenge will be running from 10:00 PM GMT on March 8, 2024, through to 10:00 PM GMT on March 10 2024, though you're definitely not expected to do a marathon 48-hour build session! You should have some time to live life in there--I know I'll be out of the apartment multiple times over the weekend, not to mention eating and sleeping...

I hope you'll all also have time to post WIP images and discussion in this thread during (and after) the build period--after all, if there's no community back-and-forth about the challenge, we might as well just be doing this on our own without any event framework.

Remember, this isn't a contest, so there won't be winners or judging. Because of that, there's not going to be strict rules--just build a MOC like you usually would (with however much or little purism you feel like using), follow the basic topic, and try to get it done in time!

Anyways, enjoy building!

[letsbuild]

I've been meaning to completely redesign my 8x8 truck, this is perfect!

I'll post updates as they come up

[2GodBDGlory]

Just now, letsbuild said:

I've been meaning to completely redesign my 8x8 truck, this is perfect!

I'll post updates as they come up

Hehe! I've been working on an large 8x8 trial truck myself for the past few days, but I'll have to come up with something else for this challenge. Time to start thinking!

[Aurorasaurus]

I've had a rough plan for a 6x6 for buwizz camp for a while, I guess we'll see where I can get to!

 

Edited March 8, 2024 by Aurorasaurus

[2GodBDGlory]

3 minutes ago, Aurorasaurus said:

I've had a rough plan for a 6x6 for buwizz camp for a while, I guess we'll see where I can get to!

 

 

That is cool! Interesting how split up the gearbox is--should be fairly durable!

[Aurorasaurus]

9 minutes ago, 2GodBDGlory said:

That is cool! Interesting how split up the gearbox is--should be fairly durable!

Hopefully- I'm planning to use 6 buwizz motors with it so it needs to be able to hold up to that.

[2GodBDGlory]

1 minute ago, Aurorasaurus said:

Hopefully- I'm planning to use 6 buwizz motors with it so it needs to be able to hold up to that.

*whistles appreciatively

[aFrInaTi0n]

I guess a trike wouldn't count as three axles? :D

[2GodBDGlory]

Not unless they're all inline with each other (3-wheel "bicycle"?), I guess!

[aFrInaTi0n]

That was my second thought.... so as it is a 48h challenge... lets see if this idea still suits me tomorrow morning... (if so, then expect it to be RC xD)

[2GodBDGlory]

2 minutes ago, aFrInaTi0n said:

That was my second thought.... so as it is a 48h challenge... lets see if this idea still suits me tomorrow morning... (if so, then expect it to be RC xD)

I'd like to see that! Very weird, very interesting

[Aurorasaurus]

Reliant robin with an extra rear axle

[2GodBDGlory]

So, I guess I should share what I'm working on:

While working on my large 8x8 the other day, I was thinking it could be fun to do a small-scale 8x8 sometime, and I think the opportunity has struck! The plan is to use 56mm balloon tires all around, though because I don't have 8 of one kind, it'll probably be modern 56x26 ones on the front/rear steered axles, and older, wider, 56x30 ones on the inner axles. Drive will likely be via two L-motors, and steering via two servo motors. I'd like to do a complicated crosslinked pendular setup for suspension, but I'll have to see if I need to simplify that to get everything to fit.

Anyways, here's my design for a front axle!

 

I'm pretty happy with the compactness and rigidity of it, so we'll see where it goes from here!

I'm going out this evening, so this'll likely be my last update of my EST day, unless I decide to stay up late and grind some more out

[Aurorasaurus]

1 hour ago, Aurorasaurus said:

Hopefully- I'm planning to use 6 buwizz motors with it so it needs to be able to hold up to that.

Got the motors and shifting motor in, I know I could use software control to set the motor up perfectly but it never seems to work with my phone, so clutch gears it is.

2 minutes ago, 2GodBDGlory said:

 

That looks like a nice setup- though I may see an issue, you may want to reinforce that steering gear to the rack some more. Or maybe I'm just paranoid about such things breaking..

[Aurorasaurus]

front axle ~done, needs a bit more reinforcement but i think its going to work just fine

[letsbuild]

After three hours, I'm here with my truck. The steering is giving me a run for my money, I'm hoping to add another axle at the front but I'm not there yet.

 

 

 

@Aurorasaurus has quite the build in the books, I hope it works out! That's a lot of power to put through one axle 🫣

 

 

 

[Aurorasaurus]

Rear axles done, gonna reinforce some more and add buwizz units, then test drive.

17 minutes ago, letsbuild said:

@Aurorasaurus has quite the build in the books, I hope it works out! That's a lot of power to put through one axle 🫣

Thanks! Yours is looking good so far too, I dont think I could have come up with that steering. Keep up the good work!

[Aurorasaurus]

Test drive done, I've got high resistance from the knob gears, but all seems well aside from that. I'm debating swapping to regular gears or not. On one hand they have far less resistance, but on the other hand even when reinforced perfectly they're still prone to skip under such high loads as I'm using them in. Any suggestions are welcome!

As for performance, its decently quick in high gear and pretty powerful in low gear, and not slow by any means.

[2GodBDGlory]

3 hours ago, Aurorasaurus said:

That looks like a nice setup- though I may see an issue, you may want to reinforce that steering gear to the rack some more. Or maybe I'm just paranoid about such things breaking..

Hmm, I can't get the gears to skip under any circumstances, so I'd assume it's fine, but I'll see when more is put together

 

1 hour ago, letsbuild said:

After three hours, I'm here with my truck. The steering is giving me a run for my money, I'm hoping to add another axle at the front but I'm not there yet.

 

That's quite similar in concept to my truck, though with fewer wheels and a different suspension style. It'll be interesting to see how it progresses!

That definitely is an unconventional steering setup, but it looks like it should work alright!

39 minutes ago, Aurorasaurus said:

Test drive done, I've got high resistance from the knob gears, but all seems well aside from that. I'm debating swapping to regular gears or not. On one hand they have far less resistance, but on the other hand even when reinforced perfectly they're still prone to skip under such high loads as I'm using them in. Any suggestions are welcome!

As for performance, its decently quick in high gear and pretty powerful in low gear, and not slow by any means.

Wow, you're really grinding!

You're right, there's no easy decision between gears and knob wheels. Knobs don't skip, but they are high resistance, and I've had problems with them just snapping in the past. Daytona diffs would be perfect for this sort of thing, except that there isn't an easy way to permanently lock them in an O-frame for off-road use

[Aurorasaurus]

5 minutes ago, 2GodBDGlory said:

Wow, you're really grinding!

You're right, there's no easy decision between gears and knob wheels. Knobs don't skip, but they are high resistance, and I've had problems with them just snapping in the past. Daytona diffs would be perfect for this sort of thing, except that there isn't an easy way to permanently lock them in an O-frame for off-road use

I reinforced the knob gears a bit more, forcing them to always be at the right angle with the suspension, and that seems to have solved the problem.

As for permanentlu locked daytona diffs, a while back I 3d printed something with the same gear shape as the daytona diff to use if I ever needed that, but unfortunately I would need to make monstrous adjustments for it to work here. Thanks for the praise!

[letsbuild]

1 hour ago, Aurorasaurus said:

Thanks! Yours is looking good so far too, I dont think I could have come up with that steering. Keep up the good work!

It's not my idea haha, that's how actual tatras steer. I'm pretty happy with how it works, though Lego's parts have so much backlash that it can lose about a third of the steering angle with flex

11 minutes ago, 2GodBDGlory said:

That's quite similar in concept to my truck, though with fewer wheels and a different suspension style. It'll be interesting to see how it progresses!

That definitely is an unconventional steering setup, but it looks like it should work alright!

I tried a solid axle first but it felt so clunky (I was probably doing it wrong) so I focused on this tatra design.

 

After five hours: 

I figured out the steering for the second steered axle. @_@ it is not simple.

I used a pair of gear racks facing each other, can't really get a good picture of it.

This is the layout, with that offset. I needed to change the toe and it turned out to be nearly the perfect solution.

Keep up the good work so far, y'all!

 

 

[2GodBDGlory]

Ah, so yours is an 8x8 too! Nice job with that complex steering!

Also, I can tell that you're Canadian because of that Mastercraft screwdriver on your desk! (Not to mention the obvious mention of it under your name)

[Aurorasaurus]

Here's where I stop for the daytime, perhaps I'll work on it some more in the evening. I'm considering swapping to RC tires, then I can use the defender mudguards on the bodywork.

[2GodBDGlory]

Here's an update before I head to bed!

I've got the rest of the axles built, and a couple L-motors installed for drive. Gear ratios could definitely be changed going forward, so this is just a guess.

I've also got most of the tricky parts of the crosslinking system in place, though it remains to be seen whether it'll have too much slack or not. Anyways, I think I'm in fairly good shape to get it done tomorrow! It'd be cool to finish up in just 24 hours instead of the full 48, but I'll have to see how it goes. That might be too ambitious!

[Stereo]

Mid-90's Ford F350 Hi-Rail.  1:25 ish so it can run on Technic Trains track (7 stud gauge).  HoG steering and hopefully a lever to lower the rail wheels.  If I can't make it work from one, then separate front+rear.

Ultimately it'll have 4 axles - 2 rail, 2 road.

At this size I think some system's inevitable, if you want a relatively gapless build.  I'm going for 10 wide cab, 11 wide utility box.

I won't be able to build it in a single colour this weekend, but if I get the functions designed enough, I'll run up a test build.  With aiming for a specific scale, working from a reference pic, and trying to make tiny mechanisms fit past each other, it's much easier for me to use Stud.io than actual parts.  Mix of studded and studless Technic in the chassis because it uses the old 1x6 Technic plates steering setup.