Wildcat 6x6

[Zerobricks]

Here's a model I actually completed a year ago in order to be unveiled in time for the BuWizz picnic back in 2021, but we all know how things went...

Anyway since the picnic did happen last weekend, I decided to unveil my most powerful offroader.

The basic design is based on the Wildcat 4x4, but this version adds more power, a 2 speed gearbox and a third axle to the formula.

As with the older version, each axle has independent suspension, plus the entire axle can pivot or swing, effectively giving this model double suspension setup. Indepedent suspension is great at absorbing small bumps when driving quickly, while the axles pivot along the terrain when crawling.

The driveline was quite a challenge. In order to transmit the power from 12 motors to the wheels, each wheel ended up having it's own dedicated 2 speed-gearbox. The final driveline is extremely compact and efficient, with only 3 gears engaged at any given time. There are also no differentials or perpendicular drives, so nothing that can break or skip.

Each gearbox is actuated by a PU M motor using worm gears, which prevent any unwanted skipping out of the gear. This way each wheel is powered by 2 BuWizz motors via a dedicated gearbox:

The following gif shows how the front axle is designed along with the whole model:

Here you can wee, how the front axle tilts in order to adjust to the terrain:

The rear axles are made in the same way as the front axles, minus the steering. Rear axles are also designed to work in tandem, when one goes up, the other goes down. When one tilts left, the other tilts right. This way the rear suspension is extremely flexible:

And finally here are some specs of this beast:

• Length: 52 cm
• Width: 26 cm
• Height: 20 cm
• Weight: 2,5 kg
• Top speed: 15 km/h (rounded up)

To complete the presentation, here's a video of the model in action, a big thanks out to @braker23, @Sariel and @kbalage for the footage.

Final thoughts... this is my most potent offroader to date. The sheer amount of power, torque and speed is hard to wrap your mind around for a model made entirely of small plastic pieces.

Having said that, I think there are still few areas to improve:

• Tendency of the front wheels to fall off at hard bumps - A lighter version would help to reduce stress on the hubs and wheels.
• Could use a higher steering angle - Would have to find a way to integrate steering racks inside the transaxles.
• Protection againt depbees and dirt entering the drivelines - Something that would also not reduce the ground clearance, tiles might work.

[nerdsforprez]

Crimony.  What a machine.  What a drivetrain.  Certainly this is one of the best performance all-Lego builds out there.  Ugly as hell but a technical heaven.  Thanks for sharing....

[1gor]

You created a monster  12 (buggy) motors  (and I feel myself happy to have one from 8421 set)

[Bony_em]

Very nice vehicle , but are so many motors necessary?

 

 

 

 

[Johnny1360]

That's what I call overkill to the highest degree, lol. It looks very well engineered and solid. Thanks

[2GodBDGlory]

Man that's cool!

It begins to remind me of hobby-grade RC cars, though of course it wouldn't compare in reality.

15km/h is crazy! I remember Sariel's Pagani Zonda topped out about there (15.4, according to Incredible Lego Technic), but that was a light, nimble, supercar. This thing is big, chunky, and even has a gearbox! Amazing power and engineering.

[Gimmick]

9 hours ago, Zerobricks said:

so nothing that can break 

 With 4 buggy motors on one axle I would call that "highly optimistic" ;D

Great offroader, a true excess of pure power!

[Mikdun]

Seen it on video - it's mighty quick. :-O

[Zerobricks]

8 hours ago, Bony_em said:

Very nice vehicle , but are so many motors necessary?

 

Having built many models with lots of motors, the bigger and more powerful models tend to have a higher power to weight ratio. Though making a lighter model usually means it's more robust and components are less stressed. Each extreme has it's ups and downs.

5 hours ago, 2GodBDGlory said:

Man that's cool!

It begins to remind me of hobby-grade RC cars, though of course it wouldn't compare in reality.

15km/h is crazy! I remember Sariel's Pagani Zonda topped out about there (15.4, according to Incredible Lego Technic), but that was a light, nimble, supercar. This thing is big, chunky, and even has a gearbox! Amazing power and engineering.

Indeed, once you go over some 10 km/h, you cana ctually start jumping over small ramps and bumps and it opens up a whole new level of performance. And I think I can make a model that can go even faster, since I have plenty of torque to spare.

[gyenesvi]

I was lucky enough to see this in real-life, amazing technical design and brutal power. I like how it showcases the way of leveraging that amount of power without overloading the plastic parts. It's cool that each wheel has its independent drive with a gearbox, and that allows it to turn in place by spinning left/right row of wheels in the opposite direction. Also the double suspension is a nice trick, and the way the pendular front axle and bogie rear axles complement each other is clever. Great design overall! This encourages me to go beyond 2 buggy motors per model, to leverage more speed, because really as you say, it's a whole new level of performance that opens up new play possibilities :D

[natesroom]

wow this legit seems like magic to me. I have no clue how to first build any of this stuff and second how to make any of this work. Great Job!!!

[Zerobricks]

So after a year of driving the model on the snow, in the dust, grass, rocks, at the BuWizz camp and finally at the Bricking Bavaria, this happened while powersliding in high gear:

After a close inspection another hub showed signs of imminent failure:

So what seems to happen is that the edge holding the hub inside the casing wears down over time enough for it to simply pop out. Now you have to keep in mind that these hubs are from 2019 and have been used in much higher speeds, loads than they were designed for, not to mention dirty environments.

What do you think? Should I get some new hubs and keep the model assembled or retire it?

What's certain is that I will be focusing on lighter models in the future which will stress the individual components less.

 

 

Edited November 21, 2022 by Zerobricks

[pow]

May be doing a 2nd Version with reinforced wheel mount? ...if possible.

Are there any (technical) museums interested in such a thing?

BTW: the color scheme is cool!

[johnnym]

23 hours ago, Zerobricks said:

So after a year of driving the model on the snow, in the dust, grass, rocks, at the BuWizz camp and finally at the Bricking Bavaria, this happened while powersliding in high gear:

Well, now we at least have a very good view inside of the wheel hub.

[gyenesvi]

Interesting, good to know the limits of these parts. Wonder when I get to this point with some of my hubs..

On 11/21/2022 at 10:37 PM, pow said:

May be doing a 2nd Version with reinforced wheel mount? ...if possible.

Not sure what you mean by that, those hubs are manufactured as a single enclosed piece, and they are the strongest lego wheel mounts in existence I believe.

On 11/21/2022 at 10:01 PM, Zerobricks said:

What do you think? Should I get some new hubs and keep the model assembled or retire it?

Not sure, maybe if you keep it you'll just continue destroying more hubs..

On 11/21/2022 at 10:01 PM, Zerobricks said:

What's certain is that I will be focusing on lighter models in the future which will stress the individual components less.

I like this direction, also, that would make it easier for us to reproduce your models :D

[pow]

@gyenesvi i expected to find a CNC-Version of this part. The Lego version is stable enough to withstand jumping. The material was abraded due to rotation. In my opinion a well lubricated CNC version would be perfect. But you guessed it: there doesn't exist something like this.

i would address this problem by putting a lego axle in two ball bearings. Here are a few quick designs.

The white round thingies at the red axle-pin-connectors should mimic two tiny ball bearings. The rest is known stuff. The blue connectors are placeholders. They are to suggest that the red connectors are somehow held.

It is just a stupid idea. No working concept. 

 

The pictures are inspired by this photo:

Source: https://www.1000steine.de/de/gemeinschaft/forum/?entry=1&id=309567

 

PS: another Link with nano bearings for trains:

 

Edited November 24, 2022 by pow

[FriedlS]

@Zerobricks lighter models would be great 😊 they produce as much fun as big models i guess. I am looking forward to it 😊

@pow ballbearings are very good and useful! I use a similar part for the use of ballbearings 😊

[Zerobricks]

Here's a very short video showcasing the Snow Edition where I replaced the wheels with tracks. As expected the model can run on the snow, but again the weight can cause it to get stuck in wet, sticky snow.

 

[2GodBDGlory]

Impressive performance for snow!

[pow]

Yay it's back. i celebrate this monster!

Would it be possible to fiddle some liftarms to the tracks to create more support surface?

[LEGO Train 12 Volts]

Just two words...pure power!