agrof

[MOC] Ultra 4 Crawler Buggy - Tested, final release!

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Hello All!

It is winter time, so I am bit more busy on Legoing. After seeing, that @Didumos69 started his 4x4 buggy project, I looked into a bit deeper the Ultra 4 racing, and the rigs been driven in this extreme events. 

Finally the video, what I linked to his topic, triggered the work on another MOC: the Ultra 4 buggy. Here is another video to see the interesting bits of independent suspension system on this beast:

 

Still, I might end up with IFS (independent front suspension) and solid axle with torque bar for the rear, but the body is heavily inspired by the Lasernut buggy.

Parameters:

  • 2x L motors
  • 1x servo motor
  • AAA battery box - in order to be replace ability with BuWizz in case
  • IR control

Let's look at into the progress a bit, maybe it is interesting to read. I started on 28. november with LDD model. To set the proportions, and the body ideas, I usually place the essential parts free in space first.

Check the real inspiration thing and the very first sketch:

640x360.jpg640x360.jpg

After that I added the electronic parts, to check the necessary minimum space. (Unfortunately Stud.io has corrupt models, so some cover parts of the motors are just not present.)640x360.jpg640x360.jpg

At this stage, I built the front axle, to see how can I integrate the steering. The answer is: massive fail.:classic: 

So back to drawing table, I deleted the 5x7 frame, and started to figure out, how to connect the needed fixation points for swingarms, servo. Due to this, the model gets more complex than I thought, but buildability is always first! I recommend to check meanwhile IRL building too, or at least stop by and thinking about how to add the related parts. I was hopeing for a simple MOC, but I ended up already a pretty complex assembly, so I made each step with double check. Later on, I will try to add groups in LDD to represent the buildability order too.

1280x720.jpg

So far the front module with steering and IFS is ready, the middle module is almost done, I am wondering about interchangable solid axle or independent solution for the rear - not sure yet. Also the color is to be decided yet, as the springs type as well (soft or hard). I think if soft ones will be OK, than I go for white body, as it presents the "rollcage" better. In case the yellow hard shock absorbers will be needed, of course the only choice is: full MEAN black body. :devil_laugh: 

This picture shows the advantage of the white body, and also a comparison for tyre types: 3740 on the left, 45982 on the right, both on 56908 wheels.

1280x720.jpg

So far 407 parts, and I guess it is about 70-75% ready. I need to figure out how to fix the roof, and create a solid, but easily disconnectable rear module. Necessary parts are ordered, so real build pics might come in couple weeks first.

And how is the road presence? I guess it will be pretty much like a punch in the face. :devil:

p.s.: Yet another WIP, I hope for long winter nights, to finish at least some of my unfinished projects... :classic:

Edited by agrof

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Very cool. I'm impressed by the use of panels.

Are you going to keep those A-pillars? The look a bit out of place sticking up. And I think you should add more "meat" to the back, with more panels/roll cage and a spare tire. These are just suggestions, do what you want with them.

I'm excited to see how this will turn out.

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I'm quite impressed. Looks very good so far.

5 minutes ago, Offroadcreat1ons said:

Are you going to keep those A-pillars?

I would like to know this as well, because I do not like those pillars.

Also, what about the Tigercat Skidder?

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Wow, very impressive progress in such a short time! I'm envious to see a whole model born in 3d, I always needed to fiddle around with real bricks... I really like the scale and especially the menacing look :) I think the A pillars are OK, adding a light bar between those 2L liftarms would make the front of the roof more unified. Can't wait to see the next steps, definitely following the build!

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Very cool looking and nicely put together! I prefer.the solid axle in the back.

One critical note: The front wheel drive won't allow more steering angle than 20 degrees, otherwise the motor will eat up the CV-joints.

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Thanks for the remarks and ideas, I store them for later tests!

For the A pillar I have some other ideas too, just like using black pneumatic hose, something like this (purple shows where it would be fitted in), simulated a bit with flex axle. This will be formed during IRL building, with LDD it is just impossible to bend the flexible parts correctly. Still, I am not fully sold on the very smooth lines here, the overall picture should be bit rugged, harsh, mean, dare to say: ugly. Like lovechild of an insect and a hammer.

800x409.jpg

@kbalage Luckily it is not much different than my daily job, also my wallet and my back are happy about 3D design.

@Didumos69 Thanks for the note, I am aware of that (spare parts stocked :wink:), looks like this will be the compromise, I need to make here. The turning radius will be probably terrible... After watching  some Axial Yeti videos, I lean also more for the solid axle - which is more less only placeholder yet in the model.

p.s.: the Tigercat is doing well, just resting.

Edited by agrof

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Update: 477 pcs, rear axle is finished, roof is attached. The only thing is missing, the pneumatic hose (black) to form the A pillars- roof side tubes - roof back, I plan to use one piece of hose going through. As you might notice, the rear shocks don't fit properly in the model, I don't have the mood to adjust everything in correct angle for now, first I want to see the characteristic of the suspension. I would be surprised if it would match for the first try...

Now, waiting for parts, and first build test can begin. I will maybe add a bit rollcage on the rear yet (no spare wheels planned, no need for extra dead weight), but not much, I kinda satisfied with the ugliness of it - even if some don't agree. :tongue: :classic: 

Also I need to test the gearing, I would like to see it climb rather than speeding, and secretly hope for good trial performance... except the turning radius as mentinod before.

1280x720.jpg1280x720.jpg

Scale comparison, a bit longer wheelbase, same track width, a bit lower than the 42037.

1280x599.jpg

Edited by agrof

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Can't wait to see it being built IRL... will not win a beauty contest but still cool :) That front view pic looks like some kind of "Ford A model got a nose job and goes to Baja" stuff :)

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Yepp, that is the goal, I think You nailed the description. :sweet: Take a rat rod, put an Ultra 4 chassis underneath, and rock it!

I played around a bit with panels for the rear segment, now it feels more complete (damn, I lack 2 white panels from my order now).

1280x720.jpg

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2 minutes ago, agrof said:

I played around a bit with panels for the rear segment, now it feels more complete (damn, I lack 2 white panels from my order now).

Wow! It looks awesome! But what will those white panels do?

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Just to have it as plan-B for hardcore crawling, I prepared a "locked differential" version too.

1280x720.jpg

Edited by agrof

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44 minutes ago, agrof said:

Just to have it as plan-B for hardcore crawling, I prepared a "locked differential" version too.

Can we see a topside image of that lime version? I'd say from what I can see that it looks better than the white.

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Sure, virtual reality is our friend, but meanwhile makes our heart sour not to having parts in wished colors... :tongue:

1280x720.jpg

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I added real rollcage, for sake of stability, the main parts are made of liftarms. The magenta colored  12M axle should prove, that everything aligned - which is actually 99% true, but as LDD approved it, I consider it legal. :tongue: It extends the roof line well, so I might keep it. Can't wait for parts arrival, fingers crossed that not much must be redesigned, and I considered all directional structural stability.

1280x673.jpg

1280x486.jpg

Edited by agrof

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Update: all the parts arrived! :sweet:

Just made a quick test, the 24x43 tires sit pretty well on 56908 wheels, they have maybe sligtly lower friction, than the 81,6 tires - if not the same. It differs a bit for each, as the old tires are... well, old.

I don't believe, that during normal LEGO crawling conditions they will fall off or rotate critically. And the main thing: they do look badass.

https://bricksafe.com/files/agrof/ultra-4-buggy/24x43 tyre 56908 wheel.jpg/1280x672.jpg

p.s.: Tomorrow I am on holiday, so some progress is planned!

Edited by Milan
Converted oversized image into the link.

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24 x 43 tires look cool with black rim. The whole moc looks very ballanced in design with panels (rat-rod style bodywork and 4 x 4 buggy chassis) and it has minimalistic approach as it is desirable for such vehicle :thumbup:

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Front axle modul is almost finished. So far so good, as planned, but pretty dense, buildable, but tiny fingers needed. :classic:

800x450.jpg

800x450.jpg

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15 minutes ago, agrof said:

Front axle modul is almost finished. So far so good, as planned, but pretty dense, buildable, but tiny fingers needed. :classic:

 

 

But it is robust, I know because I use similar setup with "H" frames on central chassis part for my Unimog :wink:

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And still not robust enough, I made bracket for the steering rack in every direction (I tought), still it can click over by 1 tooth... I assume, the gear rack itself can bend a bit and let the servo gear slip. As I am building the "locked diff" version, I figured out a way to support from underneath, unfortunately it does not work with the normal diffs so I might not publish that version.

As it should be a hardcore crawler at the end of the day, I don't mind it.

800x682.jpg

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1 hour ago, agrof said:

And still not robust enough, I made bracket for the steering rack in every direction (I tought), still it can click over by 1 tooth... I assume, the gear rack itself can bend a bit and let the servo gear slip. As I am building the "locked diff" version, I figured out a way to support from underneath, unfortunately it does not work with the normal diffs so I might not publish that version.

As it should be a hardcore crawler at the end of the day, I don't mind it.

Isn't a 3L liftarm enough, instead of the T-shape? Or maybe you can make something that is two studs wide, then it would fit with a normal diff.

Something like this:

800x450.jpg?a=1

Edited by Didumos69

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