[MOC] TATRA T815 TP 6x6 Trial Truck

[z3_2drive]

That exterior rollcage looks beautiful Are the springs too stiff? I see a lot of Tatra MOCs with sharp angles at rest, but it seems they should be partially compressed.

[HorcikDesigns]

Thank you.

@Doc_Brown - I'm not sure whether it would be legal in this years races, because they are dedicated for 6x6s, with this (http://www.artpeter.net/trucktrial/rozvor.gif) setup of axles. Also there are some limitations about the bumper, the winch and other simple towing mechanisms are required, but this suspension, whether it had the right wheebase dimensions, would be legal. ;) I like your attempt ;) (and it was a little inspiration when building mine) ;)

@z3_2drive - yes, the springs are little bit stiffer than I would like, but I have not substitution for them, so I had to use these. And yes, the axles are in very sharp angle, but when it rides, it usually gets down. ;)

[HorcikDesigns]

Hi, here is album from the race, so whether are you interested to see my truck struggling with water and mud, then you can after clicking this link. Video does still not exist. :D

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=546676 (whole race's gallery)

[Black-Build]

Looks like great fun! I wish we had truck trial competitions in the Netherlands, but it seems to be dead.

[HorcikDesigns]

Looks like great fun! I wish we had truck trial competitions in the Netherlands, but it seems to be dead.

Yes, it was great fun - and the best was the moment, when I recognised, that I have mud or something in portal-axle, that could not be disassembled :D

Edited August 24, 2014 by Gzzig

[HorcikDesigns]

Video is done yet!!!

[Black-Build]

Its an awesome MOC, only its a little too slow for me. Good luck with your next one!

[Chapachuk]

Why are the wheels at that strange angle?

[Zerobricks]

Why are the wheels at that strange angle?

Lots of people ask that... Its the type of suspension tatra uses, check here:

[hrontos]

An to complete the "why unaligned" question: older versions had them aligned by using differently size gears. Newer version prefer symmetric axles, so "unaligned" was a solution to the problem how to make left and right half-axles identical. They are shifted by 51mm and there is a difference between versions: Tatra with reduction in wheels has right half-axles shifted forward. The models without reduction in wheels have left side half-axles shifted forwards. This because half axle rotation direction is different when there is a reduction in wheels.

[grum64]

Great build

[HorcikDesigns]

Thank you very much ;)

For those who are interested - second version of this truck is still WIP in this moment, but about 80% finished yet ;) (That's a lie; I have seen many MOC presentatios, but only a few were really finished :) )

[Zerobricks]

An to complete the "why unaligned" question: older versions had them aligned by using differently size gears. Newer version prefer symmetric axles, so "unaligned" was a solution to the problem how to make left and right half-axles identical. They are shifted by 51mm and there is a difference between versions: Tatra with reduction in wheels has right half-axles shifted forward. The models without reduction in wheels have left side half-axles shifted forwards. This because half axle rotation direction is different when there is a reduction in wheels.

So some have planetary hub gear reductions and some dont have it?

[Blakbird]

Why are the wheels at that strange angle?

With a Tatra suspension system, each half axle is a swing arm which changes angle as the suspension compresses. On a real Tatra vehicle, the suspension is set up such that at nominal compression the wheel is perpendicular to the ground, so you won't see a real Tatra with such extreme angles just sitting there. This would only happen with an axle fully compressed or extended.

[hrontos]

So some have planetary hub gear reductions and some dont have it?

Yes, you can have it as an option. According to official webpage, it looks like all military versions have the reduction in wheels, in versions for mining or construction industry it is optional.

[hrontos]

With a Tatra suspension system, each half axle is a swing arm which changes angle as the suspension compresses. On a real Tatra vehicle, the suspension is set up such that at nominal compression the wheel is perpendicular to the ground, so you won't see a real Tatra with such extreme angles just sitting there. This would only happen with an axle fully compressed or extended.

On the real Tatra angles are really not that big as seen on the models. A swing upwards is limited by the rubber stop to 7°. A swing downwards is limited by the stop in the axle final drive housing to 12°.

Edited August 25, 2014 by hrontos