[WIP] 4x4 Unimog Trial Truck

[Teo LEGO Technic]

4 minutes ago, gyenesvi said:

Not the camber, rather it would improve the caster angle at the front, it would become neutral, not negative.

Ohh ok got it. I’ll redesign the chassis then, wish me luck! 

[Teo LEGO Technic]

While I'm working on rebuilding the chassis to lower the drivetrain, I also decided to redesign the gearbox. Now the actuator is centred, and this keeps the sliding motor section from getting angled by the previous off-center actuator - this means less friction, and so less power lost: 

[Mechbuilds]

You should replace those black studs into the 1,5 studs for a better connection on the linear actuator. 

[Teo LEGO Technic]

UPDATE:

The main fixes are:

1. Lowered the drivetrain in the chassis to reduce negative caster, and increase space availability (great tip @gyenesvi )
2. Used the extra space to change the mounting of the M-motor that controls the gearbox to be in the center of the chassis, above the rear axle

Another improvement was moving the diagonal beams inward to allow the suspension to attach closer to the body without hitting the chassis, and so make the side-to-side component of the suspension softer for better offroading:

Do you guys see any opportunity for improvements? How high should I make the truck rest - higher is better for clearance, but lower is better for toppling over. I will probably stick with the original Unimog design:

21 hours ago, Mechbuilds said:

You should replace those black studs into the 1,5 studs for a better connection on the linear actuator. 

Done, good catch! 

Please let me know whatever tips you guys have for improvements! I really want to nail this project, it's coming along really nice

[gyenesvi]

The driveshaft angle looks better to me now!

1 hour ago, Teo LEGO Technic said:

How high should I make the truck rest - higher is better for clearance, but lower is better for toppling over. I will probably stick with the original Unimog design:

I guess that’s a good strategy. You’ll have most of the weight low anyway, and that’s what really counts for tipping over. The cab won’t get that heavy I guess.

[Teo LEGO Technic]

8 hours ago, gyenesvi said:

The driveshaft angle looks better to me now!

I guess that’s a good strategy. You’ll have most of the weight low anyway, and that’s what really counts for tipping over. The cab won’t get that heavy I guess.

Good point, that’s my hope as well. I’m glad I went to the trouble of changing the driveshaft, it’s a substantial improvement

[Cyborg_Samurai]

On 8/12/2021 at 12:37 AM, keymaker said:

I would not say that small LA is the best option, but.... It works pretty well in my Crawler, which is not the smallest one :)

niiiiiice.... The nitro looks lit

[gyenesvi]

On 4/19/2022 at 4:36 AM, Teo LEGO Technic said:

I’m glad I went to the trouble of changing the driveshaft, it’s a substantial improvement

Good to hear, glad you didn't regret it :)

[Teo LEGO Technic]

Hey guys, I know it's been some time since the last update, but I've finally had time to put some more work in.

The chassis is pretty much completed, I only need to purchase a small pneumatic actuator to finish setting up the front diff lock, but everything is ready to install. I completed the following:

1. Added Panhard rods front and rear to centre axles
2. Modified the position and connections for the suspension to enable smoother travel
3. Installed and secured the battery box and pump with @functionalTechnic's auto-valve assembly

I'm really really pleased with the overall performance of the truck. It gets good speed in the high gear and soooo much torque in low gear, with no risk of gear damage due to the clever transmission setup.  The diff locks work like a charm, and the steering has plenty of angle as well as plenty of strength despite using a small actuator. My only complaint is that the front portal axles aren't nearly as sturdy as the rear ones, but that's the sacrifice for compactness that I have to make by using @Zerobricks custom portal axles, and they still hold together well enough to function properly (I just would like to see them strong and unbreakable for my own satisfaction). 

Here are some pics of the chassis:

 

Let me know if you guys want to see a video of the chassis overcoming some obstacles, or if it can wait until the body is finished for a full video. 

Now it's time to start work on the cabin. I've decided to go with the U5000 look, I love that simple boxy offroad look. Any suggestions for where I can find more pics of that model? 

Hope you guys like it   Let me know any tips for improvement!!

[Voldemort87]

The drivetrain looks well packed. Liking the layout. would like to see the video pls :)

[Teo LEGO Technic]

Hey everyone, I know it's been quite some time since the last update, but here it finally is 

The general shape of the cabin is done. I just put in an order for parts so the hole in the front and side of the engine cover will be filled when those come. 1x2 black beams will fill in the space on the red hoses to create nice rounded mudguards, and a small pneumatic piston will complete the diff-locking system.

After that, the only work left will be to add some seating, a dummy dashboard, and a few more details here and there. It's almost done though!!

If you guys have any advice for improvements please let me know. I tried to keep the cabin pretty basic, partly to make the model light and capable, and partly because I want to finish it soon so I can move on to a new project. Here are some pics:

[1gor]

well shape is recognizable and proportions seem to be correct. You can nake minimalistic cab for trial truck 

 

 

[Teo LEGO Technic]

On 1/10/2023 at 2:28 PM, 1gor said:

well shape is recognizable and proportions seem to be correct. You can nake minimalistic cab for trial truck

Thanks! That pic is exactly the look I'm going for, once my parts ship I'll post the finished truck ;)

[Teo LEGO Technic]

Hey guys!

Finally the truck is complete, not a lot of time to work on it these days but at last I got it done.

Please let me know if you guys see any room for improvement, and if not I'll get to the video hopefully next weekend ;)

Here are some quick pics:

As you can see, the seats are taken from the LEGO Defender. Unfortunately I had no time to come up with something new.

Edited March 7, 2023 by Teo LEGO Technic

[Daniel-99]

It looks stunning! The development process was an interesting thing to look at as well! Hope to see it in action, to conclude if all the technical solutions work together. 

P.S. I made my version of Trial Unimog last year (see the post on EB), but it looks like a toy comparing to yours!

Edited March 7, 2023 by Daniel-99

[Teo LEGO Technic]

3 hours ago, Daniel-99 said:

It looks stunning! The development process was an interesting thing to look at as well! Hope to see it in action, to conclude if all the technical solutions work together. 

P.S. I made my version of Trial Unimog last year (see the post on EB), but it looks like a toy comparing to yours!

Thanks! And cool Trial Unimog, it is indeed a much smaller scale, but it's quick

[Paul B Technic]

This is well built, I love the level of detail.