1:10 Large - scale motorized 4x4 Tow truck

[Zerobricks]

I don't usually post my work projects here, but every so often there is a special one that I really want to showcase more in detail.

Today I want to show you one of my all-time favourite projects, which is packed both full of functionality and a very high level of detail.

Before we go into the details, lets' first let's talk about the idea behind it. We (the BuWizz team) have been cooperating with Slovenian AMZS (Slovenian Automobile Association) for a while now and they are the ones who allow us to record the various speed breaking and such events on their polygon. An idea emerged for a project to design and loose replica of their existing Tow Truck which is to be used for education purposes.

Here's how one of their tow truck looks like:

I decided to use this specific model as an inspiration of my representation and here were the basic starting functions and features:

• 1:10 scale
• Capable of lifting and towing an actual 1:10 model like 42125
• All Wheel drive
• Working gearbox
• Realistic suspension
• Highly detailed

As with most of my projects, i first started working in LDD and this is what the first prototype looked like:

I took some liberty with the shape, notably I removed the crew compartment in order to better the lift arm details.

As the project progressed, so did the amount of functions, features and details until I ended up with this long list:

• Motorized with 11 motors
• Powered by 2 BuWizz 3.0 Pro bricks
• All wheel drive powered by 4 BuWizz motors
• Working gearbox with a high and low gear
• 3 differential locks
• Independent suspension in the front
• Solid rear axle in the back which uses 3x13 curved panels as leaf springs
• Working V8 engine connected to the drive motors
• Functioning steering wheel linked to the steering rack
• Motorized lift which can unfold, raise and lock onto thr wheels of the towed vehicle
• A motorized winch in the rear
• Working front LED lights
• Opening doors, hood and compartments
• Detailed engine bay with battery, air filter and washer fluid
• Compartments filled with details such as fuel canisters and various tools
• Other details include cones and fire extinguishers
• 3D printed braking discs in the front for show
• Total piece count is around 3060 parts
• Just over 3 kilograms
• 51 cm x 24 cm x 22 cm when folded excluding mirrors
• Capable of lifting and towing a 1:10 scale car like 42125 even up a steep hill
• Top speed of 10 km/h

Here's an overview of the model and the basic mechanical functions:

Driveline is powered by 4 BuWizz motors. The motors drive a 2 speed gearbox and a fake V8 engine:

Gearbox is powered by a PU M motor and uses 2 mini linear actuators to switch between low, neutral and high gear:

Each of the 3 differentials has it's own lock, actuated by a wave selector and powered by a PU M motor:

Steering system is powered by a PU L motor and uses two steering racks in order to both steer the wheels and turn the steering wheel:

Finally, there are several more PU M motors used to power the rear arm. The main actuators lift the whole arm and are powered by 1 PU M motor:

Another PU M motor is used to unfold the lower part of the lift arm using 2 mini linear actuators:

Finally another PU L motor is used to lock the wheels with two more mini linear actuators. The driveline is designed in such way that the arm can swing a bit while cornering:

The lifting arm had to be designed to be as strong as possible, yet thin enough to slide under the car we want to tow. The final version was under 2 studs high and capable of lifting a 2 kilogram heavy model with ease:

With all the details finalized and the parts omptimized in the LDD version, it was time to build the real deal:

As mentioned above, the model is full of details that can be accessed by opening the various compartments:

The rear view showing the folded tow arm and the 2 large actuators used to lift it:

Few more pictures of the model next to the real deal:

Of course no Technic photoshoot wouldn't be complete with the most important photo of them all, the underside:

The underside was left open and exposed intentionally, so that the gearbox, the differential locks and steering system can be observed.

Of course as with all the projects, this one also had some issues, the biggest being the use of 3x11 curved panels as the rear leaf springs. Originally only a single pair was used to support the weight in the rear and the additional load of a towing vehicle, but it soon proved too much for them and over time they ended up breaking. That is why for the final fix, they were doubled, to increase the stiffness and durabilty of the rear axle:

Other than this, there were no other major issues with the model. The driveline has yet to skip a gear, the joints are holding (even the small CV joint used in the front left side) and the model ended up being robust enough for some really rough driving.

As mentioned at the start of the topic, this is one of my best models to date, I'm really happy with the amount of sheer functionality, features and details I managed to cram in it and it will forever hold a special place in my heart.

To wrap up this already long topic, here's a couple of videos of it in action:

 

[Milan]

Frontpaged.

[2GodBDGlory]

Thanks for posting this! I recall seeing it on YouTube, but it's always nice to read some more details!

[LEGO Train 12 Volts]

This is a wonderful vehicle perfectly replicated from the original!

The video gives even more emphasis to this masterpiece!

[lmdesigner42]

Another amazing model! It's great to see the 3x13 curved panels implemented as leaf springs. Are they fixed to the frame at both ends, or is one side attached to a rotating link/shackle (https://en.wikipedia.org/wiki/Leaf_spring)? I can't tell for sure from the pictures.

[kopylov]

Good job! 👍

What is the purpose of rubber bands on front wheel hubs?

[Zerobricks]

50 minutes ago, lmdesigner42 said:

Another amazing model! It's great to see the 3x13 curved panels implemented as leaf springs. Are they fixed to the frame at both ends, or is one side attached to a rotating link/shackle (https://en.wikipedia.org/wiki/Leaf_spring)? I can't tell for sure from the pictures.

Thank you! They can swivel in the rear since they extend when compressed.

13 minutes ago, kopylov said:

Good job! 👍

What is the purpose of rubber bands on front wheel hubs?

The rubber bands hold the brake caliper holder represented by handles 30031.

[damian_kane_iv]

Wow very nice model! How are the front and rear difflocks? Are they stable and robust? 

Also will you be making instructions?

[Zerobricks]

9 hours ago, damian_kane_iv said:

Wow very nice model! How are the front and rear difflocks? Are they stable and robust? 

Also will you be making instructions?

Difflocks work as they should, so far no issues with them. Regarding instructions, I doubt since this was a one-off project.

[Daniel-99]

Thanks for a great presentation! I do really like the front suspension with diff lock! 

[gyenesvi]

Great model with lots of great functions, I especially like all the detailed functions of the towing arm. Thanks for posting as I have been looking for some more info about this since last year's Buwizz camp.

I have been working on a (Ford F350 inspired) tow truck alternate of 42114 in the same scale and color (but obviously with much less functions than this), and I hope you don't mind if I take some inspiration from yours as well for the looks?

Edited May 17, 2023 by gyenesvi

[Zerobricks]

19 minutes ago, gyenesvi said:

I have been working on a (Ford F350 inspired) tow truck alternate of 42114 in the same scale and color (but obviously with much less functions than this), and I hope you don't mind if I take some inspiration from yours as well for the looks?

Sure, go ahead, that's why I share my builds, to inspire others! Can't wait to see your F350, will it be in the same scale?

[gyenesvi]

4 minutes ago, Zerobricks said:

Can't wait to see your F350, will it be in the same scale?

Thanks! It should be, as 42114 has the same wheel size (on different rims) and the same wheel arches, so the front and cab could end up looking somewhat similar.

Edited May 17, 2023 by gyenesvi

[Zerobricks]

Just now, gyenesvi said:

Thanks! It should be, as 42114 has the same wheel size (on different rims) and the same wheel arches, so the front and cab could end up looking somewhat similar.

Remember that you can get the 42114's and 42110's wheel arches also in white which might be an easier color to work with.

[damian_kane_iv]

3 hours ago, Zerobricks said:

Difflocks work as they should, so far no issues with them. Regarding instructions, I doubt since this was a one-off project.

Aww that's too bad, I feel like there's a lot we could learn from your techniques. If you're working on a licensing deal and holding off until you get a definitive answer I understand... but the CAD files of your model are just as appealing lol.  

It's sad cause I feel like a lot of the best designers hold off on publishing instructions for their models. I've been waiting almost 3 years for pvdb to release his 1:10 Jesko either as a set or instructions and so far not a peep 

Edited May 17, 2023 by damian_kane_iv

[Zerobricks]

4 minutes ago, damian_kane_iv said:

Aww that's too bad, I feel like there's a lot we could learn from your techniques. If you're working on a licensing deal and holding off until you get a definitive answer I understand... but the CAD files of your model are just as appealing lol.  

It's sad cause I feel like a lot of the best designers hold off on publishing instructions for their models. I've been waiting almost 3 years for pvdb to release his 1:10 Jesko either as a set or instructions and so far not a peep 

I will ask if it's okay to share the LDD file. Regarding instructions, I doubt many people would actually be interested in the model as it is, since it's a very specific, part-intensive, expensive and complicated build.

[damian_kane_iv]

Just now, Zerobricks said:

I will ask if it's okay to share the LDD file. Regarding instructions, I doubt many people would actually be interested in the model as it is, since it's a very specific, part-intensive, expensive and complicated build.

Wow thanks so much! I feel like there might be more people who end up building at least part of it than you assume.

I should add that my background is in biology/biomedical engineering, so I'm biased towards open source and knowledge sharing everything (almost all of our research is funded by the NIH in the U.S. and it's required to be available to the public by law). My current projects is pretty rudimentary but I'll probably still publish instructions to get feedback and to share my style and techniques. 

[Axadder]

Very impressive, so much functions crammed in so little space!

[_TLG_]

Cool model with nice features!

[Crazy bricks]

Looks amazing! That is a lot of functionality too, very impressive.

[shroomzofdoom]

I realize all the reasons why you may not be able to share instructions, but I hope that some of the concepts or sub-models are things you'll be able to share in the future.

As always, your Technic design skills are in a category all of their own. I always build (or try to build) your designs, and every time I do--I learn something that I never knew before. Your transmission designs are legendary.

For example: the consideration you used when orienting this frame in a way to accommodate the 24T gear of the differential opened up a possibility that I previously hadn't considered. In making this single connection you've opened up possibilities for several other designs I've been tinkering with. 

Even if you can't share more...THANK YOU for sharing just enough. :-)

Edited May 19, 2023 by shroomzofdoom

[Zerobricks]

Thanks for all the praise to everyone. Unfortunately, I can't share the LDD file, but if anyone wants more photos of certain details, let me know!

Regarding frames, yes, due to the molding limitations, they have a slight difference in the upper and lower side, which is what I exploited in order to fit the 24 tooth gear of the differentials without rubbing. I'm really happy you noticed this, @shroomzofdoom and thank you for the encouraging words.

[Sentinel]

That is a neat leaf spring design, but it seems to create a lot of stress on parts not meant for that. I might try that design 

[1gor]

Extraordinary MOC 

[Jundis]

Really well done!