[MOC] GAZ 66 Firetruck RC LEGO Tecnic

[Danifill]

Hello! This is my new creation - GAZ 66 firetruck model! Basically, it is a Soviet water tank that is still used in Russia. It has several functions and features: driving (4X4 drivetrain with blocked differentials, Buggy motor for propulsion), steering (Servo motor), working front lights, working beacon lights, working live axle suspension on both sides, tilt cab with a decorative fake V8 engine underneath it, detailed cab interior, openable doors with rubber band locks, openable water tank's compartments with some details like a firehose, openable water tank's top and some custom stickers. All electric functions are powered and controlled with BuWizz. 

The chassis itself (without the bodework) worked really well, this is my first good try on 4X4 live axle suspension, but the sinal model has some problems because of the weight (almost 3 kg). The suspension isn't strong enough, so it leans on the sides a bit, soI think it needs some bigger dampers, as I don't quite want to use several dumpers on each wheel. One BuWizz is also not enough, because it is struggling to control that much electric functions at once with such weight. Anyways, it is pretty nice to drive. :)

VIdeo link: 

https://www.youtube.com/watch?v=cHhpBez6m0Y 

Photoes:

Thank you!

 

Edited June 16, 2021 by Danifill
the video link didn't work

[1gor]

Overall shape looks really good, but I do not know if it has portal axles...

[Danifill]

2 minutes ago, I_Igor said:

Overall shape looks really good, but I do not know if it has portal axles...

Thank you! I think that portal axles were necessary for the off-road performance, drivetrain could just break under the load. :)

[1gor]

21 minutes ago, Danifill said:

Thank you! I think that portal axles were necessary for the off-road performance, drivetrain could just break under the load. :)

I suppose you don't have hubs from 42099 set?

They have bigger reduction

[Danifill]

2 minutes ago, I_Igor said:

I suppose you don't have hubs from 42099 set?

They have bigger reduction

Yes, I don't have them. Indeed, they would fit perfectly, since this model needs a bigger reduction 

[1gor]

34 minutes ago, Danifill said:

Yes, I don't have them. Indeed, they would fit perfectly, since this model needs a bigger reduction 

Well then bricink or Zetros is your possibility (despite that IMHO Zetros is very expensive )

[Jurss]

Very well shaped, instantly recognisable. Also seating postion for driver is correct

[Aleh]

Recognizable Gaz indeed! I think such models are still works for our fire departments.

[Danifill]

2 hours ago, Jurss said:

Very well shaped, instantly recognisable. Also seating postion for driver is correct

Thanks! Seats are pretty good for Technic guys, though they are a bit small for this scale. :D

1 hour ago, Aleh said:

Recognizable Gaz indeed! I think such models are still works for our fire departments.

Thank you! :)

Edited June 17, 2021 by Danifill
misunderstood a little! :D

[gyenesvi]

This looks beautiful, very recognizable, technic panels work great for this kind of shape and luckily the color is also easy to get right :) I like your live axle suspension setups as well. @I_Igor I'm not sure 42099 hubs would clearly be easier to use. While you are right that the reduction is better, I find them hard to build into a steered live axle without loosing all the ground clearance (like the Zetros will have unfortunately). On the other hand, using the new CV-joints from 42099 instead of the U-joints could give you more strength in the drive-train I think.

[Danifill]

6 minutes ago, gyenesvi said:

This looks beautiful, very recognizable, technic panels work great for this kind of shape and luckily the color is also easy to get right :) I like your live axle suspension setups as well. @I_Igor I'm not sure 42099 hubs would clearly be easier to use. While you are right that the reduction is better, I find them hard to build into a steered live axle without loosing all the ground clearance (like the Zetros will have unfortunately). On the other hand, using the new CV-joints from 42099 instead of the U-joints could give you more strength in the drive-train I think.

Thank you very much! By the way, these U-joints are working really well to my surprise, none of them ever broke in this chassis. In my previous GAZ MOC same U-joints were more fragile, probably because there weren’t any portal axles. 

[keymaker]

1 hour ago, gyenesvi said:

I find them hard to build into a steered live axle without loosing all the ground clearance

I hope soon I will present my rock crawler with those hubs and the solution, which shows that it is not so bad with GC with 42099 hubs.

@Danifill Great functions and recognizable body. What is more, it really can drive even considering the weight.

Edited June 17, 2021 by keymaker

[Danifill]

1 minute ago, keymaker said:

I hope soon I will present my rock crawler with those hubs and the solution, which shows that it is not so bad with GC with 42099 hubs.

@Danifill Great functions and recognizable body. What is more, it really can drive even considering the weight.

Thank you! 

[1gor]

2 hours ago, gyenesvi said:

This looks beautiful, very recognizable, technic panels work great for this kind of shape and luckily the color is also easy to get right :) I like your live axle suspension setups as well. @I_Igor I'm not sure 42099 hubs would clearly be easier to use. While you are right that the reduction is better, I find them hard to build into a steered live axle without loosing all the ground clearance (like the Zetros will have unfortunately). On the other hand, using the new CV-joints from 42099 instead of the U-joints could give you more strength in the drive-train I think.

You explained this compromise in best possible way. 

[gyenesvi]

6 hours ago, keymaker said:

I hope soon I will present my rock crawler with those hubs and the solution, which shows that it is not so bad with GC with 42099 hubs.

@keymaker that sounds interesting, are you maybe ready to share ideas just about the axle itself? I am just starting to work on the motorization of a model with live axles using those hubs, and am a bit stuck (the non-motorized model uses non-portal hubs so GC is okay). So far, my best solution to the ground clearance problem is building the A arms at an angle like this, something that I used in a previous model (that one had pendular axles, not real floating ones). Not sure this could be fit into the fire truck though, maybe it's too wide.

@Danifill we can take this discussion offline if you are not interested, or we can stay here if you are, let us know.

 

[Danifill]

1 minute ago, gyenesvi said:

@keymaker that sounds interesting, are you maybe ready to share ideas just about the axle itself? I am just starting to work on the motorization of a model with live axles using those hubs, and am a bit stuck (the non-motorized model uses non-portal hubs so GC is okay). So far, my best solution to the ground clearance problem is building the A arms at an angle like this, something that I used in a previous model (that one had pendular axles, not real floating ones). Not sure this could be fit into the fire truck though, maybe it's too wide.

@Danifill we can take this discussion offline if you are not interested, or we can stay here if you are, let us know.

 

Of course you can stay here, there is no problem! It will be interesting to learn something new here. :D

[dpi2000]

Very nice, I like it；）

[Danifill]

8 minutes ago, dpi2000 said:

Very nice, I like it；）

Thanks! :)

[keymaker]

1 hour ago, gyenesvi said:

are you maybe ready to share ideas just about the axle itself?

In some sense, yes :) I apologize for kind of mysterious photo, but I still working on this project and as you can see it still needs some minor recolors and parts adjustion. But I am pretty happy with ground clearance (it is the same for LEGO tractor tires). At the picture you can see how I decided to deal with ground clearance and new hubs. Steering is done with M motor and small LA.

Edited June 17, 2021 by keymaker

[gyenesvi]

8 minutes ago, keymaker said:

At the picture you can see how I decided to deal with ground clearance and new hubs.

Thanks a lot, that looks pretty good, I have seen a similar solution previously here, but that used some weird half (or even quarter) stud offsets with a length difference between the upper and lower arm. As I see it, there is no tricky geometry here, just that the lower part of the hub is tilted inwards a bit, right? I think that's still acceptable, as when it moves up, it corrects the tilt. The only drawback of this (as well as mine above) is that it needs the CV joints for the drive from the diff to the wheels (as opposed to a straight flat axle), and I don't have enough of those, as I also want to use them for the drive going into the live axle from the body.. But maybe as @Danifill said, CV joints can also be used before the diff, as they don't take too much load yet.

And I need to get some of those tires, they look way better than the tractor tires. They are ROCK CRUSHER X/T 1.9" TIRES from RC4WD right?

[keymaker]

@gyenesvi Yes, no tricky geometry here, and yes, the lower part of the hub is tilted inwards a bit. But this tilt is so small that fully acceptable. And about new CV joints, yes, it is some sort of drawback, because my amount of those parts is based only on 42099 inventory (new CV joints are constantly unavailable on lego store and quite expensive on bricklink - at least in my country). There is a way you can avoid CV joint and still be able to use hubs - check the video, 1:33. I did not test this solution because I couldn't find my old 16T gears :P

And about the tires, there are no names tires from ali I spotted other day. But I believe that the original model is this one you mentioned.

 

 

Edited June 17, 2021 by keymaker

[Danifill]

A little update on this model!

- removed the water tank and beacon lights

- changed the livery (removed stripes; black bumper; red wheels)

- replaced yellow dampers to grey ones in the rear

- added some decorative extra lights on the roof

Now the suspension setup works properly and the whole performance is now much better!

Edited June 18, 2021 by Danifill

[gyenesvi]

17 hours ago, keymaker said:

There is a way you can avoid CV joint and still be able to use hubs

I did not mean to save the CV joints that connect to the hubs (that's just a half, the other half is built into the hub), but was talking about the one that comes right after the diff. But I am guessing that you are not using a diff, that's why you can save even more GC in the middle.

17 hours ago, keymaker said:

my amount of those parts is based only on 42099 inventory

Mine too :)

However, I have realized that it would be possible to build it with a straight axle (no CV joints after the diff, only the one at the hub). Just at the same time, this jeep topic popped up, with exactly such a build, I think it's also a really good solution:

 

 

[keymaker]

35 minutes ago, gyenesvi said:

I did not mean to save the CV joints that connect to the hubs (that's just a half, the other half is built into the hub), but was talking about the one that comes right after the diff. But I am guessing that you are not using a diff, that's why you can save even more GC in the middle.

Sure, I got you. Yes, in my model I don't use diffs (because it is designed to be totally unstoppable no matter the terrain). But even if I do, the GC would not change and the max you could see on my photo would be some tips of red teeths from diff gear :)

And the solution presented on the video. I believe it can allow to create portal hub, without an actual portal hub, with the new hubs from 42099. I hope you understand what I mean. But as I mentioned before, I wasn't able to test that idea because lack of old 16t gears.

[gyenesvi]

1 hour ago, keymaker said:

Sure, I got you. Yes, in my model I don't use diffs (because it is designed to be totally unstoppable no matter the terrain). But even if I do, the GC would not change and the max you could see on my photo would be some tips of red teeths from diff gear :)

Oh yes, because of the use of the CV joints you are able to place the gears (or the diff) one stud higher than if there was a straight axle, I missed that for the first sight! So GC is actually one stud more than I thought was possible. On the downside, that one stud extra on the top of the axle can also become problematic if there is lack of space in the chassis, for example if the steering motor was in the chassis not on the axle. It's a balance of many things, but it's good to see all these options :)

1 hour ago, keymaker said:

And the solution presented on the video. I believe it can allow to create portal hub, without an actual portal hub, with the new hubs from 42099. I hope you understand what I mean. But as I mentioned before, I wasn't able to test that idea because lack of old 16t gears.

That's an interesting solution that could work on a non-steered axle, I have run into that exact problem it is trying to solve before. I could give it a try that, I have some older gears..