GAZ 66K

[Tatrovak]

I present to you my current creation, it is a model of the Russian, respectively (considering the time of creation) Soviet light truck with increased cross-country ability, GAZ 66. Specifically, it is a version with a K66V box body. My model is driven by 4 PF L Motors, one PF servomotor provides control, two PF LEDs are used for lighting, everything is powered by one buwizz 2. When building the chassis, I tried to stick to the originals, but there are a few differences, the axles are rigid and stored, as on unimogs, in ball studs and transversely they are established by tie rods. They are sprung with four hard shock absorbers. The differentials are only in the axles and are without locks. For several reasons, I used wheel hubs with planetary reducers. The cabin is foldable and can be simply completely dismantled. Buwizz, which is located under the cab, can be switched on without tilting the cab.
The superstructure is attached to the chassis with four locking pins, so it can also be quickly dismantled.

 

[1gor]

Is there a posibility to see complete front axle?

Thank you

[Tatrovak]

Here you go

 

[1gor]

Thanks.  It seems that we had similar ideas...

I'm just looking how to make 2 studs more narrow steering axle with planetary hubs...

This one is a bit wobly...

Edited December 10, 2023 by 1gor
I hope I didn't derail your topic.

[Jurss]

1 hour ago, 1gor said:

2 studs more narrow

Then you will need to saw/cut something like @Tatrovak did ;)

[1gor]

9 minutes ago, Jurss said:

Then you will need to saw/cut something like @Tatrovak did ;)

Or to find out how to enforce my previus solution...

 

Edited December 10, 2023 by 1gor

[Milan]

Frontpaged.

[Tatrovak]

First of all, I thank the moderator for putting me on the front page, it's the first time for me and I really appreciate it.

The stiffness of the axles is complicated, I don't pay much attention to this concept of rigid axles, I have always preferred independent suspension, especially the Tatra suspension concept (or better said my interpretation of the Tatra suspension concept, since it is quite difficult to imitate from Lego) or double trapezoidal suspension, but on this creation I was reminded of the advantages of solid axles.

In any case, if I can advise, you need to take more care in connecting the halves of the axles together, I know it's a problem with the differential, which takes up a lot of space, which in combination with the fact that you definitely want, like me, to maintain the highest possible ground clearance, I don't know if that's understandable I explain, my English also has its reserves, but there is simply a weak center around the differential on your axles, if I understood correctly that bending of the axle, and the resulting unwanted positive deflection of the wheels, is the problem we are talking about here. If so, then another way I fight against it is that I place the lower arms with ball studs that hold the wheel hub not perpendicular to the wheel hub, but at an angle (the primary purpose of this solution is to improve the ground clearance of the axle) and not perpendicularly, which creates a negative deflection of the wheels which compensates for possible lateral bending of the axle itself.

As for cutting the parts, that's something I don't like to do, but considering that I mostly try to stick to the width of the 21-hole model, just like in the case of this GAZ, I couldn't solve it otherwise, so I'm certainly not very happy that I have to use non-original tires or Buwizz, but unfortunately LEGO does not offer us in this area, in my opinion quite good products.

And one more thing comes to my mind, in my opinion it is more advantageous to place the steering mechanism behind the transverse axis of the axle, not in front of it, regarding the approach angle and the final appearance.
And if you want to make the front axle as small as possible, move the servo motor past it somewhere in the frame, if there is room for it, even though I don't really like this solution because of the clearance in the telescopic CV joints that you will have to use.

[1gor]

I had the same problem, so I'll probably test my "new" idea during week to see if I can make proper drivetrain (with enough pulling power) by using older (non reduction) hubs from 42054 set. Using older hubs I can achieve desired stiffness, but need to see how to manage high torque of coupled XL motors...I have some ideas, but I have to see what is dooable spacewise...

Kind regards

Edited December 10, 2023 by 1gor

[Tatrovak]

But for handling the torque, those wheel hubs with a reduction are absolutely ideal, it has been confirmed to me many times that the use of wheel reductions is very important, especially for larger models, whether to reduce the stress on the drive train, the smoothness of the operation is better with them, and especially no other wheel hubs from LEGO do not have less wobble.

[1gor]

7 minutes ago, Tatrovak said:

But for handling the torque, those wheel hubs with a reduction are absolutely ideal, it has been confirmed to me many times that the use of wheel reductions is very important, especially for larger models, whether to reduce the stress on the drive train, the smoothness of the operation is better with them, and especially no other wheel hubs from LEGO do not have less wobble.

On my axles wobble comes from suspension arms needed to be used with reduction hubs because there is no technic connector with ball socket.

Another solution would be that LEGO makes yellow defender wheels, but now we enter wishes area...

Model that I plan to make is some 36-37 studs long and max 20 studs wide

[Tatrovak]

I rather hope that LEGO will finally offer some more compact parts with which the wheel hubs with reductions could be attached to the axle, or I would be grateful for a version of them that would have pin holes instead of ball studs, but how do you say it they are just our wishes, because just yesterday I discovered a whole topic here in this Technic forum about wishes about parts.

[1gor]

3 minutes ago, Tatrovak said:

I rather hope that LEGO will finally offer some more compact parts with which the wheel hubs with reductions could be attached to the axle, or I would be grateful for a version of them that would have pin holes instead of ball studs, but how do you say it they are just our wishes, because just yesterday I discovered a whole topic here in this Technic forum about wishes about parts.

Yes I would that too; but there is no possibility to use pinholes because it is sungear in the way, so ball or pin should stick up from top and bottom... IMHO easieat will be to make something like this part but with ball socket and not pin socket...

Yes topic about parts needed is really something special. 

[2GodBDGlory]

On the topic of making skinny axles with planetary hubs, here's an option I just thought of:

It has rather poor ground clearance, and isn't quite as strong as a proper ball joint connection, but it seems to work fairly nicely

[1gor]

8 minutes ago, 2GodBDGlory said:

On the topic of making skinny axles with planetary hubs, here's an option I just thought of:

 

 

It has rather poor ground clearance, and isn't quite as strong as a proper ball joint connection, but it seems to work fairly nicely

I have tried that some year and a half ago, but wasn't satisfied...pehaps I have overlooked something

[Aleh]

Exterior is wow! Looks like real model, because I know this model very well! So recognizable, brilliant work! All shapes, proportions! Simply wow!

[Tatrovak]

The solution posted by 2GodBDGlory is interesting, I didn't think of anything like that, but as he said himself, the ground clearence restriction is too big.

Thank you very much for the compliment Aleh, I tried for the most realistic design in combination with the best driving characteristics, as I always try.

[gyenesvi]

I just realized that it was the planetary hub that you had to cut to make this work. I wish Lego would have made that hub that way, it becomes so hard to use as a steered hub because of that extra bit being in the way all the time. That's what happens when they want to make a part usable for multiple purposes; it becomes much less useful for its original purpose. At least with the Audi hub, they made it better.

The truck looks nice, especially the cab, I'm not a fan of big boxy stuff, so I prefer it without the rear end :)

On the other hand, I don't like the front axle construction, because of the use of the ball joint causing negative caster. Did you consider building a proper 4-link suspension for the front? And moving the servo off the axle through a linkage? At this large scale, it should be possible.

On 12/10/2023 at 10:20 AM, 1gor said:

I'm just looking how to make 2 studs more narrow steering axle with planetary hubs...

Do you want 11 stud wide axles (between steering pivots)? I don't think that's possible with current parts, but the 13 wide you have here can be made fairly stable (while having okay ground clearance like the one in this post), you just need to get rid of that servo on there, move the cross bracing on the top closer to the center, and maybe turn it into a proper 4-link suspension :) Something like I used in this build.

[Tatrovak]

When I bought 8 pieces of these wheel hubs with a planetary reduction about three years ago, I immediately modified 4 pieces in this way, because from the first moment that those parts were introduced in set 42099, I knew that the parts that I cut off would interfere with the steered axles, and it doesn't matter if it's solid axles, Tatra axles (for which I primarily bought the wheel hubs) or double wishbone. On the other hand, so that I don't just complain about them except for this detail, these wheel hubs were, and still are, a miracle for me, and they moved, especially my folding to a higher level. And as I already mentioned here, I was not happy that I was going to cut into them (especially when I take into account that I paid 10 euros for one at the time, since it was a novelty at the time), but only the modification made them the part that I he wanted.

Thanks for the compliment, I probably had the most trouble with the cabin.

As for the construction of my front axle, you have to take into account that if you want to use your Toyota FJ40 as an example, first of all there is a huge weight difference between these two models, and regardless of that, I always try to include elements such as is to make the chassis as robust as possible, since I expect that the final model will not be light. This is also reflected in the steering, any attempt to move the servo motor outside the axle would inevitably increase the backlash in the steering, whether I would use a shaft with a cross joint and a telescopic element or a tie rod, especially when steering through a tie rod, then not only steering backlash is reflected in the steering itself, but also the clearance in the bearing of the entire axle, and the heavier the model, the worse it is. I also have doubts about whether the four-link suspension would work in my model, and even if it did, it would certainly not be more robust than what is there now.

But I want to say that I hope that nothing I write here is offensive, because I value every advice, and I am very glad that I have someone here to discuss LEGO with.

Overall, I think it's mainly about the fact that everyone has a different style of assembly and my front axle is a result of my experience and I'm satisfied with it, and for example the negative deflection of the wheels is a purpose not a consequence, because the real GAZ 66 also has a front axle slight negative deflection of the wheels.

[1gor]

5 hours ago, gyenesvi said:

 

Do you want 11 stud wide axles (between steering pivots)? I don't think that's possible with current parts, but the 13 wide you have here can be made fairly stable (while having okay ground clearance like the one in this post), you just need to get rid of that servo on there, move the cross bracing on the top closer to the center, and maybe turn it into a proper 4-link suspension :) Something like I used in this build.

Yes, I plan to make it 11 studs between steering points...I have an idea; similar I have posted in my tread while ago, but now I have to wait when my wife calms down (we had virus infection and we become wrong medicine so she went from bad to worse).

Kind regards

[muffinbrick]

Congrats to frontpage, your MOCs have always high level of autenthicity. I'm not fan of cutting, but in this case I somehow understand it.

[Tatrovak]

Thank you for the compliment, I try to be authentic and use original solutions. I take the cutting as a kind of compromise between using only lego parts and creating my own on a 3D printer, although actually, regardless of the cutting, few of my creations are only 100 percent from lego parts, since I use Buwizz and I also use tires mostly from others manufacturers, since with the Lego ones it's a big misery, at least for me.

[gyenesvi]

21 hours ago, Tatrovak said:

As for the construction of my front axle, you have to take into account that if you want to use your Toyota FJ40 as an example, first of all there is a huge weight difference between these two models, and regardless of that, I always try to include elements such as is to make the chassis as robust as possible, since I expect that the final model will not be light. This is also reflected in the steering, any attempt to move the servo motor outside the axle would inevitably increase the backlash in the steering, whether I would use a shaft with a cross joint and a telescopic element or a tie rod, especially when steering through a tie rod, then not only steering backlash is reflected in the steering itself, but also the clearance in the bearing of the entire axle, and the heavier the model, the worse it is. I also have doubts about whether the four-link suspension would work in my model, and even if it did, it would certainly not be more robust than what is there now.

But I want to say that I hope that nothing I write here is offensive, because I value every advice, and I am very glad that I have someone here to discuss LEGO with.

No worries, there's nothing offensive here, good to have a discussion with someone who understands the trade-offs in such designs. I think you see things quite similarly how I see them, in terms of possibilities and trade-offs. I agree that a steering system is most responsive if the servo is on the axle, and that the biggest challenge about the linkage based steering when the servo is off the axle is the clearance it requires (furthermore it requires a Panhard rod as well to be stable). However, I don't quite understand why a 4-link would be less stable and less usable for a heavier truck. In my experience it can be built quite stable, especially with stronger links (built from towball arms) and using a Panhard rod. Sure it is quite a bit more complicated than using the ball joint, but it's exactly that challenge that I am looking for when building them :) Also, what I found is that when the servo is on the axle, it requires a hole in the front of the chassis, and that makes it less rigid. When the servo is in there, it can be used as a structural element as well. But I understand we have different building styles / goals.

21 hours ago, Tatrovak said:

Overall, I think it's mainly about the fact that everyone has a different style of assembly and my front axle is a result of my experience and I'm satisfied with it, and for example the negative deflection of the wheels is a purpose not a consequence, because the real GAZ 66 also has a front axle slight negative deflection of the wheels.

I did not know that the real one also has some negative angle, good to note. I'm actually okay with using the ball-joint in the front when it is almost horizontal or only has a minimal amount of negative angle (what I don't like is steep negative angles). And trucks are better candidates for that.

[muffinbrick]

Well, using buwizz or different tires is in "legal" category for me, because it don't directly influence, how is something build, it just add more power, or more authentic look. Cutting, or 3D printing, on the other hand can change directly building process - you can build, what would be impossible by original LEGO parts. In case of those planetary hubs it's bit of gray zone for me - you can use hubs without planetary reduction, which have needed shape, or you have planetary hubs, which have different shape of connection ports. It's pitty, that LEGO don't made those planetary hubs in shape of those from Audi q-tron. It would be problem solved.

[gyenesvi]

47 minutes ago, muffinbrick said:

It's pitty, that LEGO don't made those planetary hubs in shape of those from Audi q-tron. It would be problem solved.

Something like that, it would be useful if they were interchangeable for example. On the other hand, there's a crucial difference; the steering arms are centered vertically on the planetary, which I do find useful and easier to work with in many cases (for example, not being in the way for things like springs).