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THIS IS THE TEST SITE OF EUROBRICKS! ×
THIS IS THE TEST SITE OF EUROBRICKS!

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Posted

Its that time of year again, to make something big to crawl over stuff. This time I decided to make a massive truck with 8 PP wheels.

p1150583.jpg

After trying different designs in LDD I decided to use turntables in order to use planetary gear ratios inside each wheel like this:

planetary.gif

This way the end torque is high and the total half axle gear ratio is 1:5 allowing the truck to generate lots of torque with no problems of gear slippage or axle bending. To power the truck I used a combination of RC and PF's. The two independent RC motors use two indpendent gearboxes in order to power indpendent left/right side wheel drives. This way the trucks steers better.

p1150586.jpg

The PF M motors steer and switch gears, they are controlled by the RC unit.

Suspension is a tatra styled design, which allows high ground clearance, robust design and is simple and reliable.

p1150587.jpg

p1150589.jpg

The real life test came when it was time to shoot a video for the truck. I managed to find a nice muddy terrain with lots of bumps to try the suspension.

p1150590.jpg

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Checking sideways stability. The truck never flipped:

p1150592.jpg

Going through sticky mud. The truck was ablt to go through mud with no issues.

p1150593.jpg

One of the toughest challenges is when going uphill. I managed to go up an uneven slope with no slippage.

p1150594.jpg

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Another important test is the test of chassis. For best performance it should bend as little as possible.

Notice the rear spoiler falled off, the ebnd is not as high as it looks:

p1150600.jpg

p1150601.jpg

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All in all I am very happy with this truck. Its one of my most capable and relaible big sized 8x8 so far.

Specifications:

Power: 2 RC motors

Gearbox: dual synchronized gearbox

Final gear rations: Low 1:50, high 1:16,67

Length: 60 cm

Width 23 cm

Height (-antenna) 22 cm

Weight 3,2 kg

Please check the video:

Thanks!

Posted

It's unstoppable! The opening shot is great. Could you explain how the gearbox works, specifically how the two M motors are controlled from a single output?

Posted

The gearbox uses old ifferentials as 24 tooth gears and 16 tooth gears to get 1:1 and 1:3 gar ratio. Instad of using the usual gearbo handle, I used a 1x3 half beam, to move both gearboxes (left and right one) at once. In order to controll 2 M motors from RC motor i used the RC unit's steering ouput to steer the old 9V switch, which gets power from main motors and uses it to power the steering M motor. The secondary RC unit's output powers the egarbox M motor via PF convertible cable. Thanks for the praise"

Posted

Best Trial Truck ever?

Congratulations, zblj! You're a genius

All functions work very well, I especially like the suspension. It looks so real!

Maybe you can take time to make a more detailed cab. I am sure that the chassis will handle the additional weight with ease

And of course we need MANY pics of all the mechanisms of your truck :sweet:

Posted

Nice work Zblj! I am glad you have returned to Tatra 8 x 8 (the first time I've met you in person you've been hiding behind one of those monsters).

How are the technic turntable and planetary gears holding? I understand the in-wheel reduction, however you still have 8t gears. Well, I just made a TT once or twice before and they were quite sensitive.

Whenever I see a new and improved model from you I do ask myself a question - can you do even better. And you keep surprising me :classic:

Great job!

Posted (edited)

Nice work Zblj! I am glad you have returned to Tatra 8 x 8 (the first time I've met you in person you've been hiding behind one of those monsters).

How are the technic turntable and planetary gears holding? I understand the in-wheel reduction, however you still have 8t gears. Well, I just made a TT once or twice before and they were quite sensitive.

Whenever I see a new and improved model from you I do ask myself a question - can you do even better. And you keep surprising me :classic:

Great job!

Thanks! The 8 tooth gears are holding good, i checked them after shooting and there was no damage. The fact the load is evenly spread over 4 gears helps them to carry lots of power with no problems.

Edited by Zblj
Posted

Same if i'm not a fan of 8*8 Trial Truck ( i think that 4*4 is much performant because they weight less and undergo under less stress), you did a good job !

I particulary like the planetary gear !

Posted

@ Zblj: Would you be willing to post the LDD .lxf file of your Planetary Gear assembly, like you did with your other excellent creations (like the Lynx)? :blush:

planetary.gif

Posted

Surprisingly goes very well even with those massive wheels. If I were in your position, I would do the rear in red to go better with the stickers.

Posted

Wow! I really love this model, it will be very nice to see it loading another car when crawling in mud!

I specially like the engineering resources to avoid the big PF-RC mocs problems in movility and steering.

I just make an entry in my technic blog for this big model, I hope you like it, if not tell me...

Tatra blog entry

Posted

Wow! I really love this model, it will be very nice to see it loading another car when crawling in mud!

I specially like the engineering resources to avoid the big PF-RC mocs problems in movility and steering.

I just make an entry in my technic blog for this big model, I hope you like it, if not tell me...

Tatra blog entry

Tank you very much, I like it!

  • 1 month later...
Posted

Hello Zblj!

I just got my hands on a full set of the Power Puller wheels, and I'm even MORE impressed with the truck you've build. Just now i'm starting to imagine how big it actually is. WOW! *oh2*

I would really appreciate it if you could share the construction of the planetary gear reductuon for the wheels, using a technic studless turntable. I have the feeling that this might be the best possible solution to make a sturdy and powerful mount for those huge wheels.

Will be looking forward to your reply!

Thanks!

Posted (edited)

Hello again!

Today I put together the planetary hub. Amazing piece of engineering, very happy with how it works!

Can't wait to build a wheel base and connect it to it!

I did some modifications though, since i don't have one of the parts.

All the parts i changed are in red. Take a look at it and tell me what you think.

P.S.

Oh, and thanks to Superkalle for the information on how to unloack LDD extended mode!

Edited by le60head
Posted

@ le60head: When one clicks on the link you provided, we see a Bulgarian website asking for a login. The limit for attaching files to your post is 150k (not 3.61k, unless you already used 146k of your 150k allotment). We can't find the .lxf file link, and many people don't understand Bulgarian. Could you post the .lxf file here?

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