8x8 Avtoros Shaman (Madoca1977), 46490 Planetary Hub mod

[Ankoku]

So, I am looking to build @Madoca 1977's Avtoros Shaman.

You can find it here:

And here:
https://rebrickable.com/mocs/MOC-5360/Madoca1977/avtoros-shaman-8x8/#details

Some time has passed since it was designed, new parts are now available and I want to build it with the new planetary hubs.

Does anyone have any ideas on how this could be done? The new hubs have some unfortunately placed elements to them and the design of the Avtoros steering/suspension system is very tight.
I have done some renders of the issue here:

The IO file is here (For those asking, I haven't done the entire thing in Studio. I wanted to model this bit, to try and find a solution to the hubs):

https://bricksafe.com/files/Ankoku/avtoros-8x8/Shaman_8x8.io

Any inspiration/help would be much appreciated. Have been staring at it for days.

Was hoping that the new liftarms with perpendicular holes might help, but they don't resolve the main issue.

I have looked at the two LEGO sets that use them, but they take a far simpler approach.

One of the main issues is that the linking arm needs to be at the height it is, otherwise the steering stops the suspension from having a full range of motion.

Edited September 6, 2021 by Ankoku

[brickless_kiwi]

I don't want to be the bearer of bad news but having built this in real life. Its very dense and you cannot just simply swap a part out.  I'm sorry to say it would be a total redesign from the ground up....

[astyanax]

Nothing is impossible... but yeah sometimes the price is as high as a redesign. I've also found before that there's a profound lack of parts featuring a ball cup, especially small/short ones. Perhaps have a look are what the non-Technic range has to offer -- it has helped me out before.

https://rebrickable.com/parts/?get_drill_downs=&q=Cup&part_cat=9

Oh and isn't there a problem that 32494 let's the axle slide whereas 52731 doesn't?

[HectorMB]

Indeed, I built the Avtoros few months ago with the new hubs... and encountered the same issue than you. To solve it I had to make a custom piece, which is to twist 90° the 5L link used to connect the hubs to the steering rack, so i could make the following setup. In this way, I managed to minimize the structural changes. I am very sorry that I do not have better and more accurate pics... 

https://drive.google.com/file/d/1_J9J5UX8sFo55Y6Yb_1TxpHvf-FscVN1/view?usp=sharing

https://drive.google.com/file/d/11KA2JYmcJOVSOYR90BcALfeghg_2r7en/view?usp=sharing

I am also sorry that I do not know how to show the pictures when are uploaded elsewhere... ;)

[Ankoku]

Okay, so the custom piece explains a lot of things.

I tend to upload images to https://bricksafe.com and just past the link to the image in here.

Thanks for the photos!

[Ankoku]

It is a shame that LEGO decided to redesign the hubs. It makes their use far more restrictive.

[HectorMB]

Well, the new hubs have a potential that the previous versions didn't. Is true that their geometry is not identical to previous ones, but i think it is not a big deal in the long run. 

If you don't want to customize any part, you may use the regular 5L links and put a perpendicular connector like in the 42099's front axle. I think it should work. 

[Ankoku]

Yeah, it was just that the balls on all 4 points of connection were more versatile. All I can guess is that their were strength issues with them.

[HectorMB]

That is indeed true. I mean, honestly, i agree with you that the might have ended up in a better structure. But at the end, they are not bad and having and axle and a pin hole bring some potential combinations as well. 

[Ankoku]

The fact that we now have planetary hubs at all is an amazing thing! So I am very glad that LEGO brought them out.

Here is an image of the 42099 approach you mentioned, so others can see what you mean:

[HectorMB]

That's exactly what I meant, yes. I am sorry i couldn't post a pic, but i do not have my computer with me right now. 

Nevertheless, to increase the resistance of the 2L axle, you can use a 3L axle and place in the lower part a 2L liftarm with axle hole.

Edited September 7, 2021 by HectorMB

[suffocation]

2 hours ago, Ankoku said:

Here is an image of the 42099 approach you mentioned, so others can see what you mean:

The (minor) problem with that approach is that you'd have Ackermann even in crab mode. This part here should do the trick:

Edited September 7, 2021 by suffocation

[HectorMB]

19 minutes ago, suffocation said:

The (minor) problem with that approach is that you'd have Ackermann even in crab mode. This part here should do the trick:

That's also true. But, in the other side, using that part you may have 2 issues:
1) the strengh that holds the axle on that part is not that strong as in the setup of the 42099. In consequence, and because that the 1L with pin hole piece is inserted from up to down, it will go out of its place quite easely, I think. 
2) In case that the piece holds in place, when the wheel is raised, thanks to the suspension, above an horizontal position, you might also have issues with the steering, as the 5L link that connects the hub to the steering rack will colide with the hub itself. 
At least, those were the issues that I found when finding a solution for the Avtoros and, in general, when using the new hubs in vehicles with suspension. 

[Ankoku]

Just doing images to visualise the discussion



The suspension moving above horizontal was the no. 1 issue I came across.

[HectorMB]

I would say that this setup won't solve the issue. I rather think that with this one, you will have issues with the steering with the wheel in the lower position, isn't it?

Edited September 7, 2021 by HectorMB

[Ankoku]

The biggest issue is that it is 1 stud out from the position of the original. Which means it gets in the way of all sorts of things.

[HectorMB]

1 minute ago, Ankoku said:

The biggest issue is that it is 1 stud out from the position of the original. Which means it gets in the way of all sorts of things.

Using the 42099 setup you may link the 5L link to the axle hole of the steering rack, solving the 1-extra stud width, I think (that's why I use that setup in the hub, so you can use the link in vertical... I don't know if I manage to explain myself! ;) )

[Ankoku]

Is there a 5L link. I am only seeing a 1x6 L link.

[HectorMB]

I meant the 6L link, sorry! I'm getting old and my memory fails! >_<

[vascolp]

I know it is easier to write than actually do it but...

Could this old part help? 6571: 

 

Also, it is a bit rare part....

[Kladovec]

I´ve ask Efferman to make this part some years ago  as replacement for that really rare and expensive part.

Maybe that it will be handy.

 

[HectorMB]

I have to say that the twisted 6L link is quite handy...

[Ankoku]

4 hours ago, vascolp said:

Also, it is a bit rare part.... 

Just had a look. I have 14 of those not used in sets. I am rich! That is what happens when you buy a bunch of sets 2nd hand, just for the wheels :P

[pleegwat]

Which degrees of freedom does this need? Would rotating the planetary hub 90° help?

[HectorMB]

I'm afraid that's not possible, @pleegwat. The Avtoros is able to turn in regular ways and in crab mode too. This means that all the wheels should be able to turn. Turning the hub 90 degrees will restrict the movement only to the vertical for suspension.

Edited September 12, 2021 by HectorMB