[MOC] Crusher 6x6 unmanned combat vehicle

[Samolot]

This time something completely different. Let it not be that I build only Russian ironwork. This time, my own design, inspired by the American Crusher combat drone.

 

When I saw it for the first time, I immediately liked the design of the suspension. Soon I started figuring out how to do it with Lego. The problem was that no Lego tires fit the scale, but luckily I had MilSpec at home which I used in my AJBAN.

The construction of the suspension went quickly, the problems started during the tests. I dreamed that the vehicle was dynamic, but here the obstacles stood in the way: the weakness of Lego motors and the soft rubber compound from which the tires are made. The Crusher does not have a classic steering system, it changes direction by varying the speed on the wheels on both sides just like a tank. So you can imagine the friction the motors have to overcome to flip a model weighing more than 3 kg on 13 cm diameter tires.

In the first variant, I developed a special gearbox for it, in fact, six synchronized gearboxes tied to six PF L engines. I naively thought that I would be able to get excellent off-road capabilities in one gear and dynamic flat driving in the other. In practice, the speeds in both gears, despite the large difference in gear ratios, hardly differed and the complex gear shifting system could not be synchronized.

So I simplified the design and used more powerful PF XL motors, I also reduced the gear ratio and used planetary hubs. It was a bit better, but only on a suitable surface, such as fine gravel or pebbles. On the asphalt, the rubbers put up a huge resistance and on the slippery surface, the wheels spun in place. The use of Xerion tires helped, and in this variant, I adapted the chassis to my Zil Peacemaker.

 

However, the use of these tires changed the proportions of the model completely and was not suitable for the Crusher. It was necessary to further work and to use rollers limiting the work of the wheels to the sides, stiffening the frame of the vehicle and making it slimmer, and using three Buwizzes, one for each pair of wheels, to drive. 6x PF XL and 3x Buwizz and planetary hubs are a satanic combination and give the model incredible power in the field like a beast, but it maneuvers well only on loose surfaces or on the wooden floor.

I was a bit ashamed that such a large model has so few functions, so at some stage, I developed a gripper on a boom that could pick up "valuable remains, e.g. radioactive" from the battlefield, load them into a special chamber, and then by opening the hatch in the chassis to drop the load for underground silos. But the whole thing was weighty and the smooth maneuvering of the vehicle had to be forgotten, so I dismantled it.

Interestingly enough, for the first time, I was able to use the 19086 element in a meaningful way.

On the visual side, I wanted to stick to the original for a while, but quickly found it simply ugly and decided to give it a bit more aggressive form.

I am already working on another version of this vehicle, this time with a more classic steering system. The movie is not mine, for the first time, made by a friend from DR Ebike, I am curious how you like it.

Gallery
https://bricksafe.com/pages/samolot/crusher

https://www.facebook.com/PawelStefaniukSAMOLOT

Edited February 2, 2021 by Samolot

[Milan]

Wow. Moving and maneuvering a vehicle so heavy with such a grace and ride so smooth...well done!

[astyanax]

1 hour ago, Samolot said:

Interestingly enough, for the first time, I was able to use the 19086 element in a meaningful way.

Bonus points for this! I ordered a couple of those 2 years ago, but I have yet to use them, even in a non-meaningful way haha!

[HectorMB]

I trully like this. Is true that 3 buwizzes is a monstruosity, but on the other hand, thinking about achieveing such potency that you can see in the real model... i have no other approach in mind!

I like also the suspension mechanism and, indeed, i wondered about a really flat model, based on your suspension mechanism than can be flipped and the wells can turn "to the other side" so it can continue moving. Just one idea more on the pile...

Anyway, i think that, with your skills, you can improve the model to make it cooler than it is already! :)

[proran]

Very cool model. The description of all the difficulties you've faced makes it even cooler. I really dig the color scheme with wheel caps in three different shades. Somehow it works really well. And the presentation is top notch. One question: how do you drive the geared hubs in such a limited space? Is there enough space for the mating cv-hoint part, a gear, and support? A picture will be much appreciated.

[Aquarius]

Really cool model, the new hubs allowing it to not momentarily stop when hitting an obstacle. I realise the video was edited by Dr. e-bike, what editing software did they use? Those transitions look amazing.

[Paperinik77pk]

What a beast!!! I love the way the suspension is adapting to the terrain!!!

Great work - thanks for sharing!

Davide

[LEGO Train 12 Volts]

Gorgeous machine!

Great video and powerful model!

[Woodstock pl]

This is very good off-road, and looks stunning 

[gyenesvi]

Amazing machine! Great suspension, nice colors, and cool video!

I have also been experimenting with a similar (rear) suspension using the large turntables and the portal hubs, but could not drive the wheels in a slim enough design for the suspension to remain stiff and not bend sideways. That chain of gears in each swing-arm must generate some friction, doesn't it?

On 2/3/2021 at 3:31 PM, proran said:

One question: how do you drive the geared hubs in such a limited space? Is there enough space for the mating cv-joint part, a gear, and support?

I guess the key to that may be that the portal hub sticks out from the swing-arm to the side, creating space for the cv-joint.

By the way, are those rims standard? The portal hubs seem to go deeper into it than to the standard tractor rims.

[Fluwoeb]

Great use of the new technic hubs and the larger turntables! I love the design! Not many people go for a simple swingarm per wheel in vehicles such as this. I love to see the different suspension designs in larger models! 

Thank you Samalot for your post!

 

[Fluwoeb]

Also, I like the video, it is great! Very clear, not shaky or very blurry, but focused.

Edited February 5, 2021 by Evan-Eleven the Engineer

[Samolot]

On 2/3/2021 at 3:31 PM, proran said:

Very cool model. The description of all the difficulties you've faced makes it even cooler. I really dig the color scheme with wheel caps in three different shades. Somehow it works really well. And the presentation is top notch. One question: how do you drive the geared hubs in such a limited space? Is there enough space for the mating cv-hoint part, a gear, and support? A picture will be much appreciated.

[proran]

@gyenesvi @Samolot Thank you, guys!

[HectorMB]

@Samolot, what are these shock absorbers? 

Many thanks!

[Samolot]

 

Front and rear

https://rebrickable.com/parts/48912c01/technic-shock-absorber-115l-complete-assembly/

middle

https://rebrickable.com/parts/76320c01/technic-shock-absorber-10l-damped-normal-spring/

[Samolot]

On 2/3/2021 at 7:19 PM, Aquarius said:

Really cool model, the new hubs allowing it to not momentarily stop when hitting an obstacle. I realise the video was edited by Dr. e-bike, what editing software did they use? Those transitions look amazing.

The movie was made on Blackmagic DaVinci resolve 17 program.

Edited February 10, 2021 by Samolot

[Aquarius]

4 hours ago, Samolot said:

The movie was made on Blackmagic DaVinci resolve 17 program.

Yeah dr ebike replied on yt

[Samolot]

On 2/5/2021 at 12:40 AM, gyenesvi said:

By the way, are those rims standard? The portal hubs seem to go deeper into it than to the standard tractor rims.

This is standart lego rims.  https://rebrickable.com/parts/22969/wheel-62-x-46-technic-racing-large/

 

[allanp]

I really like how, despite it's weight, the movement is so smooth, the wheels don't stop or wobble about at all when they hit an obstacle. It just continues on like it's made of steel. 

[MajklSpajkl]

Excellent footage and great rover! I like the colours a lot and looks really strong. Seems unstopable. Well done.

[Samolot]

Thanks guys for the positive response.