Truck Trial Mercedes Uniknick

[Tamas Juhasz]

I present my newest trial truck, a pretty special one, this Mercedes Uniknick:

(folder: http://www.brickshel...ry.cgi?f=515930 )

ORIGINAL:

http://www.brickshel...spiration02.jpg

This construction has central steering, this allows to have only one gear from the driving motors to the wheels. Reduction is 5:1, or 3:1 (has enough torque with it). I didn't want to make an average central steered vehicle like dump trucks, so I decided to add something new. One of the problems was the stability. This kind of off road vehicles like to fall over, that's enough when one section(front or rear) is turned 90 degrees.

So this one has a linked like suspension, but with gears and turntables instead of links( not my idea, TT made it in this truck: http://www.brickshelf.com/cgi-bin/gallery.cgi?f=444654 ):

So this construction allows to do these at the same time:

There is two version from this truck, one with PP wheels(secondary version) and the one with cutom RC4WD crawler tyres(primary model). The PP wheeled truck weights 1767 g, the crawler wheeled 1423 g. I know, it looks much better and realistic with the RC4WD tyres, that's the main reason I used them. The tyres give a bit better climbing abilities (PP wheels are still good), the highest obstacle was 1,5 times bigger than the wheels's diameter.

For steering there is one XL motor to have enough power to do it. It's necessary because of the 16 t turntable driving gears, there are two of them, one on each side to make the steering reliable. There weren't any problem with it.

Front lights:

The hardest part in the building process was to make the central part, to be reliable and functional with keeping the proportions of the original Uniknick.

I made a video for each version. Note the PP wheels abilities compared to the crawler tyre.

RC4WD Crawler wheel:

PP wheel:

Hope you like it.

Edited December 17, 2012 by Mbmc

[Edwin Korstanje]

This is a hell off a good truck trial and the third party tyres work stunning with it :thumbup:

[hrontos]

Very nice and effective design.

At first sight I thought that battery box is may be too high, but the performance in the videos is simply amazing. With every new obstacle I expected that it must the limit but it looks like it has no limits.

I like how the central steering helped you to climb the stairs.

[Lipko]

It's so cute, it actually climbs the rocks.

[DLuders]

I like how you used those RC4WD Rock Crusher X/T 1.9 Tires on the Lego 44772 wheels! They sure are a lot more grippy than the Lego 32298 Power Puller tires (which are reportedly "deleted" by the Lego Technic Designers, per this recent TechnicBRICKS article).

Specifications of RC4WD ROck Crusher X/T 1.9 Tires:

Outer Diameter: 4.25" (107mm)

Width: 1.53" (38.9 mm)

Inner Diameter: 1.9" (48mm)

Each tire weight: 3.3 oz / 93 g

Edited December 18, 2012 by DLuders

[AndyCW]

Like so many threads on this forum, you have inspired me. I am thinking about a much smaller truck that utilizes the small turn tables and linking the axles via gears.

[kieran]

That central steering is really nice, very simple in the gear train but looks to be very strong, very good performance on the truck

[clarkdef]

If only legos crawler worked this well. Amazing vehicle it ticks all the boxes, I could become attached to this model if I had built it, and even come to love it never willingly to take apart, it would remain forever in my heart... But hell yeah awesome model, and I subscribed too.

[Kierna]

Very clever truck It looks like a monster truck with the PP tyres and the flag on top

[SergLG]

Cool truck!

[Gene]

I like this truck very much! It's cute, powerful and sturdy. The sound from the motor as though turbo spooling when it climbed over your finger~Cool! Overall score much much better than 9398 with those 3rd party tires. Will be glad to build one too!

Edited December 29, 2012 by Gene

[Zerobricks]

Really cool. With so little gears between motors and driveaxle this sure is efficient!

[Morj]

The funny thing about this design is that it's more complicated than the original uniknick design where the cab with the engine is fixed relative to the front axle (it can be clearly seen on googled pictures of uniknick).

I even found a replica of this design on brickshelf:

But sure adding a mechanism keeping the cab with the heavy battery box only at only half the angle of the axles is helping weight distribution.

[Tamas Juhasz]

Thanks guys.

Yes, it's more complicated than the real Uniknick. This complication is needed for the much better weight distribution. This kind of vehicles can easily fall over.

I even found a replica of this design on brickshelf:

I hold that in my hands at our Malug TT meeting last year. That's a really well made Uniknick with realistic design, as always by Zoli. But there was a couple of roll over during the race. Then later, in september, the central steered TTs with the Uniknick's simple suspension also loved to roll over. That's why I wanted to try out this suspension. The battery box is quite low, turns half with the cab of the axle's turn. That helps a lot, but even this design isn't as stable as a regular 4x4 TT with linked suspension and PP wheels. But has an advantage: allows to integrate the efficient drive train with simple design, even the 3:1 gear ratio (36t - 12t gears) was enough to climb the obstacles in the video.

[rumpletump]

Very nice job.. It works so well... I am impressed

[Morj]

This complication is needed for the much better weight distribution.

The battery box is quite low, turns half with the cab of the axle's turn.

Totally agree, I even wrote that myself in my comment (below the picture)

BTW, I created a very compact version of this steering/articulation part, is anyone interested? Or should I build a truck around it first?

UPD: added a post about it.

Edited January 14, 2013 by Morj

[legomuppet9]

BTW, I created a very compact version of this steering/articulation part, is anyone interested? Or should I build a truck around it first?

I am very interested, but make a new topic to showcase it...

[sverre]

This truck really performes well! I´m impressed. Going to try to build one myself :)

[TGS]

I was so impressed by the design and the offroad ability of your Uniknick that I had just to get my own truck to play with. I hope you don't mind! Thank you very much for this great and have to say cute truck. It looks like a little dog when it climbs over obstacles. Very well done!!!

[1gor]

14 minutes ago, TGS said:

I was so impressed by the design and the offroad ability of your Uniknick that I had just to get my own truck to play with. I hope you don't mind! Thank you very much for this great and have to say cute truck. It looks like a little dog when it climbs over obstacles. Very well done!!!

 

 

It is very nice replica, but I have simple adwice - please contact @Jim or @Milan if it is not better to start new topic and give credit to @Tamas Juhasz instead bumping into very old one 

But once again it is very nice moc 

[Aleh]

Such "angry" look 

[Svart]

Had this topic not been bumped I would never have found it. I´m a big fan of the Unimog and had no idea you could build a Lego RC crawler that works this well. Now I want to build one myself! And a trailer for it to be pulled by my Arocs :)