[MOC] Star 266 - Truck Trial Championship Edition [free building instructions]

[keymaker]

Hi,

I would like to present you my first MOC prepared especially for official LugPOL Truck Trial Championship.

MOC is based on very famous, polish truck with good off-road capabilities - Star 266. I choose polish truck to introduce some local technology to the competition dominated by soviet machines.

Instructions are free of charge, so if you have parts and some time, you can enjoy off-roading with this model pretty easy. LINK

 

 

Here are my priorities when designing this truck:

1. to fulfill LugPOL Truck Trial Championship rules and to provide truck which will be accepted by judges
2. to prepare truck with good off-road capabilities
3. to build it to make it recognizable

Couple of LTTC rules:

• scale: 1:12 to 1:14
• number and type of axles true to the real machine
• type of suspension true to the real machine
• must be RC and all-wheel drive
• the truck's cabin true to real machine, with roof, seats, steering wheel, floor and with openable doors

All above rules were fulfilled, below there are couple of more details:

• scale: 1:12
• drive: 2x PF XLs coupled, if necessary, each wheel can harness power of two XL motors
• steering: PF L motor
• weight: ~1990g
• dimensions: W x L x H: 25 x 64,5 x 32,5 studs (width without wheels and tires)
• Star is powered by Buwizz 2.0, but since it uses only PF motors in very simple configuration, it can be powered by anything you have

Truck was designed to work with 96mm Tamiya CC01 tires, and those tires you will see on the video. But in the instruction I used the closest in case of size official Lego tires. You can of course put bigger tires, like Lego tractor tires: 107mm, but some rubbing during extreme off-roading is possible.

Couple words on the truck itself:
Star 266 took part in two competitions in 2023, so it is well tested, any minor issues were eliminated and I'm convinced, that it can be used in hard terrain without any worries. It is rather simple construction, to reduce the weight. Details are there mostly to be able to fulfill competitions requirements.

The truck is the mix of many ideas I had during designing and I wanted to test during proper, official competitions. Some of them proved to be hard terrain effective, some of them, not. So this is for sure not the ideal trial truck. But it is not afraid of outdoor obstacles, mud, dirt, stones etc.

Pros of Star 266:

• high ground clearance (7 studs with 96mm tires)
• high approach, break over and departure angles
• highly response suspension with long travel to fast and precise surface adaptation
• each axle is connected directly to coupled 2 PF XL motors, which allows to stable, equal speed of all wheels and provides (when needed) all available power for the wheel which needs it the most
• steering is done with PF L motor for speed and strength, possible steering angles are > 45 degrees per site

Cons of Star 266:

• turntables used in each wheel introduce friction, quite a lot of it, I highly recommend to try to reduced it as much as possible (I advise to use a bit of sanding or lubrication, or both)
• due to lack of any shock absorption, stability is only on decent level
• truck's cabin shape and location is not the best in case easy passing the gates during competition, but this is my personal opinion

Internals of the MOC, so drivetrain and steering with motor on front axle

 

More photos: https://bricksafe.com/pages/keymaker/trial-truck-star-266

Edited August 3, 2024 by keymaker

[1gor]

It looks nice and simple trial truck; question - is it possible to put XL motors closer so you can use less gears?

(Using 40 tooth gears instead of 24 would not help...)

[2GodBDGlory]

Very cool to see a full-on Trial Truck with free building instructions! I think the 8:56 portal axles always make for pretty intense-looking trucks! Unfortunately I only have 2 of them, which will prevent me from trying this model out myself. :( I also like the use of those old Bionicle frames in the front hubs!

[Paul B Technic]

Amazing, well presented too.

[keymaker]

9 hours ago, 1gor said:

It looks nice and simple trial truck; question - is it possible to put XL motors closer so you can use less gears?

(Using 40 tooth gears instead of 24 would not help...)

It is most probably possible, but current setting is used mostly to get proper gear ratio on drive shaft to have proper, reasonable speed of whole truck.

[1gor]

16 minutes ago, keymaker said:

It is most probably possible, but current setting is used mostly to get proper gear ratio on drive shaft to have proper, reasonable speed of whole truck.

As I can see, you have made upgear 24 to 12 and downgear 8 to 56 giving final torque at the shaft 7 / 2 × (14.5 x 2). In brackets are mentioned two XL motors and their torque.

Kind regards

...alltogether some 101 Ncm torque...

[keymaker]

19 minutes ago, 1gor said:

As I can see, you have made upgear 24 to 12 and downgear 8 to 56 giving final torque at the shaft 7 / 2 × (14.5 x 2). In brackets are mentioned two XL motors and their torque.

Kind regards

...alltogether some 101 Ncm torque... 

You need every single Ncm of torque you can get from those two XLs. Below you can see video from LTTC 2024 Competiton 2, where we had Sariel with us, so there is very nice video recording of the competition. It was not as demanding in case of the power of trucks but you can see how LTTC looks like. I was there of course, you can find me on the video, but I drove successor of the Star 266.

But the first competition from this year took place I would say in high mountains, so here, torque was more than necessary. I have photo of it, but not video prepared.

Edited August 4, 2024 by keymaker

[1gor]

I know; that is why my Fastrac 4220 has coupled XL motors with 28 to 20 upgear, thdn gray differential and reduction hubs...and 156Ncm on axle...with 107mn Xerion tires...

I saw several times truck trials and very often I look video by Pavel with comparison with Zetros

[burak]

Cool model, a pretty minimalistic build with the main focus on its capability. That onboard shot was very cool 

Would love to see more use of onboard cams in truck trials, but I believe the added weight would be too big of a disadvantage

[keymaker]

10 minutes ago, burak said:

Cool model, a pretty minimalistic build with the main focus on its capability. That onboard shot was very cool 

Would love to see more use of onboard cams in truck trials, but I believe the added weight would be too big of a disadvantage 

I consider that, but as you mentioned, this is additional weight, which is not welcomed (but manageable) also placing the camera is problematic, since if I put it outside of the truck dimension, it can be impossible to pass the gates without time penalty. Last but not least, I still didn't buy any decent camera for such purposes :D

[NV Lego technic]

On 8/4/2024 at 11:55 AM, keymaker said:

you can find me on the video, but I drove successor of the Star 266.

When? And what's the successor?

[keymaker]

5 hours ago, NV Lego technic said:

When? And what's the successor?

My truck has my nick on the back, so I believe it should be pretty easy to say which one is mine :D In case of the model, the successor is based on AM General M818 military truck.

Edited August 8, 2024 by keymaker

[1gor]

When I recovered from dizziness caused by intro in uploaded video; I must admit your model and yellow cabover 8 x 8 are my favorite looking; so smooth, somple and then again trial trucks.

[gyenesvi]

That is some badass trial truck in a large scale! Very well made, I like the simplicity of the hardcore functionality and it also looks great, especially with those RC tires (I can see many people are using them in the trial race as well, and I understand why, very good ones). And I like those portal axles and that front axle steering with that huge gear :)

The competition sounds like a great fun, great looking builds all over the place, so many huge and powerful trucks!

[Hrafn]

I think that is the first time I have seen someone find a good use for those Bionicle frames - nicely done.  And the truck is great too 😊

[1gor]

7 hours ago, Hrafn said:

I think that is the first time I have seen someone find a good use for those Bionicle frames - nicely done.  And the truck is great too 😊

I saw that used by @Thirdwigg years ago on his blue truck; Mack 55 ir something...idea is great. I was using those to streagthen chassis when 5 x 3 with perpendicular holes was not in production...

[Thirdwigg]

3 hours ago, 1gor said:

I saw that used by @Thirdwigg years ago on his blue truck; Mack 55 ir something...idea is great. I was using those to streagthen chassis when 5 x 3 with perpendicular holes was not in production...

Yeah, those parts are great. I still use them every once in a while. I think this was the first truck I used them on.