Truck Trial 56mm competition

[mahjqa]

Pretty much all it says on the tin- competitors are limited to wheels no larger than 56mm, max width is 17 studs (stickie-outie-bits like mirrors are OK), motors, power supplies etc should be 100& Lego, no 3D printed parts- very conventional. 

 

 

We found out during the trial that the obstacles may have been a bit too hardcore, but we intend to do it again with improved machines and gained knowledge.

[Jurss]

That second truck :D

And poor droids :(

[gyenesvi]

Oh, I'd love to take part in such a competition, great scale, cute builds, I actually have a design I'm working on right now that could fit this :)

I wonder what that -6 score for the last entry? That kind of put it from 1st place to last place.. Was it not a proper truck build, or cheated in any other way?

[mahjqa]

10 minutes ago, gyenesvi said:

I wonder what that -6 score for the last entry? That kind of put it from 1st place to last place.. Was it not a proper truck build, or cheated in any other way?

That -6 is because it's my own truck. As organiser, I'm not eligible to win any prizes.  
The other positive scores you see in that column are rewards for originality / looks.

[gyenesvi]

9 minutes ago, mahjqa said:

That -6 is because it's my own truck. As organiser, I'm not eligible to win any prizes.  
The other positive scores you see in that column are rewards for originality / looks.

Oh, I did not connect the dots.. makes sense, and good to hear, because I really liked that one for its simplicity and solid looking mechanics :)

[nerdsforprez]

Pure, silly fun.  Thxs for the post.  Enjoyed hearing grown men laugh in the background and enjoying themselves...

 

[2GodBDGlory]

That does look like a lot of fun!

That clone juggernaut trying to take on obstacles with plastic wheels was pretty silly!

[Thirdwigg]

Very cool. I long for this kind of event in my area. Maybe it's time for this kind of event at Brickworld Chicago next year.

[keymaker]

Great idea, I wish to be part of it.

[Appie]

3 hours ago, keymaker said:

Great idea, I wish to be part of it.

You sort of were. A few of us (I think I did it the most) took alot of inspiration from your Kraz 255 for you axle setup (and skid plates ). For fun I made it 9 wide instead of 11 wide (no dual drivetrain though), which made the car 15 studs wide, 2 below the allowed maximum. In hindsight not the best choice, I nicknamed my little car "the tumbler" after seeing the video where it's upside down quite a few times (and in the ranking as well)

 

Originally both axles have steering, but one of the cv-joints on the rear axle kept popping so I adjusted it to a fixed axle before the video of the truck trial. Thought I'd mention that in case somebody wonders why the rear axle isn't steering in the video.

 

Edited March 13 by Appie

[keymaker]

@Appie thank you for kind words. I'm glad that my MOC were useful for some people :) Those words give me motivation to go back to MOCing, since I have couple of unfinished projects on my shelf still waiting due to some changes in my personal life.

[piterx]

7 hours ago, Appie said:

You sort of were. A few of us (I think I did it the most) took alot of inspiration from your Kraz 255 for you axle setup (and skid plates ). For fun I made it 9 wide instead of 11 wide (no dual drivetrain though), which made the car 15 studs wide, 2 below the allowed maximum. In hindsight not the best choice, I nicknamed my little car "the tumbler" after seeing the video where it's upside down quite a few times (and in the ranking as well)

Originally both axles have steering, but one of the cv-joints on the rear axle kept popping so I adjusted it to a fixed axle before the video of the truck trial. Thought I'd mention that in case somebody wonders why the rear axle isn't steering in the video.

dude this truck looks so good!! I love it

Edited March 14 by Milan
Removed quoted images.

[gyenesvi]

@Appie, thanks for showing that model in detail, it is a beautiful looking one with a great compact form factor. I was just wondering how the axle is built in such a narrow space with those deep rims being used, but now I start to understand. Is the steering geometry actually Ackermann on that? What / how many motors is it driven by? PU or PF?

[Appie]

22 hours ago, keymaker said:

@Appie thank you for kind words. I'm glad that my MOC were useful for some people :) Those words give me motivation to go back to MOCing, since I have couple of unfinished projects on my shelf still waiting due to some changes in my personal life.

Glad to hear it. Keep on MOC'ing, you make awesome stuff.

19 hours ago, piterx said:

dude this truck looks so good!! I love it

Thank you very much.

Here's another pic of it:

 

8 hours ago, gyenesvi said:

@Appie, thanks for showing that model in detail, it is a beautiful looking one with a great compact form factor. I was just wondering how the axle is built in such a narrow space with those deep rims being used, but now I start to understand. Is the steering geometry actually Ackermann on that? What / how many motors is it driven by? PU or PF?

It's driven by PU, 1 L-motor for drive and one L-motor for steering.

This is basically what's under the bodywork:

This was an early version, tweaked a few things since this picture. Mostly the 3 points where the axles are linked to the chassis (made the LBG 5L suspension arm in this picture parrallel to the 6L links so the suspension worked better). The reason I mounted the motors like this was so I could get some good gear reduction under it to crawl up obstacles.

Yes, it's ackermann, like the original axle from Keymaker. Here are some close up shots of the axle.

 

 

 

Keymaker could use 2x 5L thin liftarms for his axle, but for 9L I was a bit stumped for options. While making this axle I found out there's actually a thin 9L liftarm now, with 3 holes which could work for this setup, it's in the new Orient Express set.

Since I didn't want to pay €5 for a single liftarm, I came up with another solution.

 

The little rubber thing on top turned into the connector is to stop the connector from seperating (without it, I'd tear it apart when just removing the wheel). It adds a little bit more flex to the axle (wheels pointing outwards) than it probably would have with a 9L thin liftarm or Keymaker's 11 wide solution, but I had no other ideas or parts that were half a stud high and had a pinhole at the end.

 

To prevent CV-joints from popping and have a little less flex on the axle, I started to build an axle with the new CV-joints similar to the one from this topic:

My version so far of his axle:

 

 

In order to make the axle sturdy where the one from AutoBacon used a 3rd party part, I needed 1 more stud towards the rear (where the red axle pops out, also the red axle is a place holder for the new CV-joint of which I ran out atm )

I want to figure out a way to lower the springs 1-2 studs. Not that I mind the solution from the original designer by just using springs, but I personally like to also have a "normal" alternative when I use that.

Edited March 14 by Appie

[Thirdwigg]

Watching this thread is getting me excited about RC trucks again. These axles are great.

[AutoBacon]

Nice work on the front axle. It's interesting working at these small scales, there are only so many designs because there is such little room for excess parts, yet there is always someone to take an idea and  make it better :D

[gyenesvi]

On 3/14/2024 at 6:09 PM, Appie said:

This is basically what's under the bodywork:

Thanks for showing the details, nice compact chassis. I like that axle construction from @AutoBacon, both the original and its evolution. It's great that it uses the new CV joint. Only thing is when I tried it I did find a slight shortcoming; if you mount the rim as close as possible (without any spacer) to this part (to have good scrub radius)

then its edge very slightly rubs that rim on your last picture and does not run completely smooth (also slightly tilts the rim). It needs a bit of releasing to avoid that, but then it becomes a little wobbly (and still can touch). It would be great if this problem could be solved, because otherwise it's a very nice construction. It seems that it's somewhat less tight with the Mustang rims that you have on the previous pictures, but then you loose the extra CV axle length that could be used to better secure the wheel (and can fall off).

The construction works well with slightly bigger Arocs rims though (at a bit larger scale).

[Appie]

2 hours ago, gyenesvi said:

then its edge very slightly rubs that rim on your last picture and does not run completely smooth

Yup, another builder noticed that while we were making the models (sadly he couldn't join for the video). Mahj's little truck from the video uses the same new CV-joints with that part and uses a 2x2 round tile with a hole in it to fix this rim touching problem (the extra surface also helps against the wobble you mention). As you can see in my picture I am using a 1/2 technic bush. For now at least, I'll probably change it to Mahj's solution. Ideally you want something of a 1/4 bush as a spacer to not rub the rim, but a tile is the closest we are going to get to that I think.

As for the Mustang rims, I personally didn't notice a difference between them and the normal standard rim in terms of touching the above pictured part.

Another solution would be this rim: https://www.bricklink.com/v2/catalog/catalogitem.page?P=6595#T=C

With this rim the part does not touch the rim, but it's not a current rim, it was used in sets until 2006, but there is a 56mm tyre that would fit this (the red fire truck in the video uses these rims+tyres).

 

4 hours ago, AutoBacon said:

Nice work on the front axle. It's interesting working at these small scales, there are only so many designs because there is such little room for excess parts, yet there is always someone to take an idea and  make it better :D

Thanks, I love working on these small scales, like you said, you need to pick your parts carefully. For example, originally I removed that thin 7L liftarm at the bottom of the steering rack from your great design, then I noticed it functioned as a steering stop and prevented a little bit of the wheels bending outwards. So I put it back in  I love such effective part usage.

Edited March 17 by Appie

[gyenesvi]

1 hour ago, Appie said:

but a tile is the closest we are going to get to that I think.

Actually, we can get to half a tile using the Mustang rims :) Inside a mustang rim, we can use 2 round plates + 1 round tile with hole as spacer, that is altogether 1 stud + half a tile. I tried, it looks good in terms of spacing. The only downside is that we loose the same amount of axle holding the rim, so I don't know how easily it would fall off then..

1 hour ago, Appie said:

Another solution would be this rim

I never saw that one, seems available and cheap, the problem is that it does not fit the small tractor tires :(

Or we could just use a thin cardboard ring with a hole punched in it :) Would that be allowed in such a competition?

[Stereo]

6 minutes ago, gyenesvi said:

I never saw that one, seems available and cheap, the problem is that it does not fit the small tractor tires :(

It's a funny shape, one big and one small bead, the small one does actually fit the current size tires.  Though it's some tiny amount different (1LDU? 2LDU? Eyeball can only say less than half a plate for sure)  I don't know if mounting tires that way is secure enough for powered stuff though, it might start spinning on the wheel.

Edited March 17 by Stereo

[mahjqa]

Finally had some time to document my build:

More pictures: https://flickr.com/photos/28134808@N02/albums/72177720315500612

IO file of the suspension: https://drive.google.com/file/d/1GSviTWD-voyIgLJKGDotRwY6L_854uuE/view

 

Edited March 17 by mahjqa
Render had to be fixed

[Appie]

4 hours ago, gyenesvi said:

Or we could just use a thin cardboard ring with a hole punched in it :) Would that be allowed in such a competition?

For this competition it was not, had to be 100% Lego. And actually, even if it wasn't a rule, I'd make it a rule for my own model. I like to keep my building solutions within the Lego options. 

[2GodBDGlory]

3 hours ago, mahjqa said:

Finally had some time to document my build:

More pictures: https://flickr.com/photos/28134808@N02/albums/72177720315500612

IO file of the suspension: https://drive.google.com/file/d/1GSviTWD-voyIgLJKGDotRwY6L_854uuE/view

 

Nice! That one's got another interesting solution for the front suspension

[Appie]

Finished the chassis for that new axle I posted earlier, inspired by AutoBacon's work

I wanted to keep the heavy parts of the model as low as I could, so I placed the battery box right above the drive shaft. As you can see I didn't manage to lower the front springs 1-2 studs. I might change the LBG part of the springs to yellow or something so I can hide it in the hood . The rear axle is pretty much a copy of AutoBacon's, except for the springs and I used another grey link on top (for symmetry with the front axle as the front has 2 as well to make sure an old style cv-joint for the steering won't pop out).

Wheelbase is 18 studs. 3 studs shorter than my previous truck and if I am not mistaken 1 stud shorter than AutoBacon's pick-up truck (I was aiming for the same, but I misscalculated ). Gear reduction is 2.8:1. It climbs better than my previous truck. That truck had 4:1 reduction, but I think with the slippery obstacles and that with these tractor tyres, having some speed to get a running start on an obstacles helps. The balance is also far better with the lower center of gravity.

Now to figure out what kind of body I want on it (will be something pick-up or Jeep-ish probably).

[gyenesvi]

2 hours ago, Appie said:

Finished the chassis for that new axle I posted earlier, inspired by AutoBacon's work

That's some amazing compactness there, interesting driveshaft.

Speaking about changing the LBG part of the spring to another color, just wondered if this spring construction would be deemed legal? Could solve the spring lowering problem..

It is made of official lego parts only, without physical modification (only spring disassembly), in a way that the parts are not damaged and the spring can be reassembled into its original form. The top connector can be easily swapped to other shapes/colors as needed.