TerraLiner:12 m Globally Mobile Beach House/Class-A Crossover w 6x6 Hybrid Drivetrain

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And many of the world's “bad roads” run straight through dry riverbeds that are, well, usually dry. But during the rainy season they become rivers, and vehicles have to cope accordingly:














As the last video suggests, sometimes the bridge that crossed the river has simply disappeared......

Furthermore, certain routes require crossing a river as a matter of course, whether the season is wet or dry.

And given that the TerraLiner will have CTIS (central tire inflation/deflation), the TerraLiner should be able to drive along sandy beaches just fine, where this is allowed, as it is in many places in Australia such as the eighty-mile beach -- see http://en.wikipedia.org/wiki/Eighty_Mile_Beach and http://www.eightymilebeach.com.au/7108/HOME/. But this may mean crossing a river at a certain points that intersects the beach:



[video=youtube;Lniv_8zEni0]https://www.youtube.com/watch?v=Lniv_8zEni0 [/video]



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4. Bad Roads After the Rainy Season


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Now after the rainy season, the gullies that remain have often become deep ditches or trenches, potentially hazardous obstacles that have to be somehow negotiated and crossed:








[video=vimeo;49639315]https://vimeo.com/49639315[/video]


Admittedly, much of the driving depicted in these videos is actually "off-road", and not strictly speaking "bad-road". But you get the picture.....:sombrero: Indeed, these various videos demonstrate that the line between "true off-road capability" versus "mere bad-road capability" is not that clear-cut or well-defined.

Furthermore, even excellent paved roads can be washed out by a torrent of water, if the flood is strong enough, and drainage was not sufficient:











To cite just one example: although the Chinese are currently paving the G-219 across its entire length, the "word in the street" is that the G-219's pavement will last only a few years. According to the locals, wind and water erosion, ice, cold, and rock falls will break up the pavement in no time, making the G-219 once again little better than a gravel track for much of its length.


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5. Crossing Erosion-Created Trenches


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In short, it seems to me that a “Bad Road” capable vehicle like the TerraLiner, even though not designed for extensive off-road use, should nonetheless be able to cross “natural” trenches. It should be able to easily cross the kinds of trenches and ditches that get left behind after a flood has done its work, and turned what was previously a passable dry riverbed, into a something that's now more like a deep gully.

Trench-crossing or ditch-crossing, it seems to me, is a potential problem that the TerraLiner will have to face, even if it drives mostly bad roads, and does not do much off-roading. And that's why I discussed and illustrated trench-crossing at great length, in posts #1372 - #1375, on page 138 at http://www.expeditionportal.com/for...edition-RV-w-Rigid-Torsion-Free-Frame/page138 .


In a nutshell: I would very much like to know whether a Chinese Six will do a much better job at ditch, gully, and trench crossing, than a more conventional 6x6.


And once again, I posted those images and videos of various Tatra 813 Chinese Sixes, hoping that perhaps someone else might be able to find a segment that "looks like" trench-crossing. But I did not post them to suggest that the TerraLiner should be able to enter truck trials! That would be absurd.

Now as near as I can tell, there are no videos available on-line of a real, full-scale Tatra 813 Chinese Six crossing a trench. My research capabilities are reasonably formidable, but I have not been able to find any further information, photos, or videos of full-scale vehicles (the Kamaz Typhoon, the Tatra 813 6x6) that might illuminate the trench-crossing capabilities of a Chinese Six. If anyone reading this knows of such media, PLEASE POST!!

In the absence of such media, to determine the trench-crossing potential of a Chinese Six, we are going to have to imaginatively extrapolate on the basis of:

(a) more videos of 8x8 trucks crossing trenches, and
(b) videos of RC models of trench-crossing by Tatra 813 Chinese Sixes.



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6. More Videos and Images of 8x8's Crossing Trenches


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Here is I another video of a Tatra 815 8x8 crossing a trench, and this time it's a more "realistic" trench, with walls of soft pliable earth, as opposed to concrete. See about 4 minutes, 30 seconds into the video:



[video=youtube;quVx8a5MSQI]https://www.youtube.com/watch?v=quVx8a5MSQI [/video]








I also found a video of a MAN-KAT 8x8 in Iceland crossing a crevasse, as well as another video of the same MAN-KAT fording a river:










Although these are not videos of 6x6s, they are sill very useful, because they suggest that crossing a trench -- even for a big powerful 8x8 -- is much more perilous and "messy" in reality, than it first seems in theory.

For instance, when the ground leading up to the trench is not flat, but rather slopes downwards towards the trench, there will be a tendency for the first axle to "dive" into the trench. Notice how this happens in both of the videos above. Whereas this does not happen to the Tatra 815 8x8 in the video that I posted earlier, on page 138 -- again, see http://www.expeditionportal.com/for...edition-RV-w-Rigid-Torsion-Free-Frame/page138. In that earlier video the Tatra crossed a concrete trench in a very controlled, artificial environment, a "demonstration ground" where the trench was a perfect geometric construct, and the ground on either side of the trench was perfectly flat -- see about 1 minute 45 seconds into the video:






But how often will any vehicle encounter such geometrically perfect conditions in real life? So this video's depiction of trench-crossing seems rather sanitized and unrealistic. It makes trench-crossing look much easier than it actually is. Whereas the first two videos above show what trench-crossing would be more nearly like, in the real world.

The only other videos that I've come across of full-scale vehicle that seem broadly relevant to trench crossing, are (a) the one on the left below, in which a Tatra 8x8 crosses a very large ditch, and (b) the one on the right, in which a MAN-KAT crosses the drainage ditches that run beside a highway:



[video=youtube;UcEIV-PUiKg]https://www.youtube.com/watch?v=UcEIV-PUiKg [/video]


If you think about it, this ability of large MAN or Tatra 8x8s to cross the drainage ditches that run alongside roads and highways is a critical operational feature. Without this feature, these would not be true "off-road", cross-country military transports, and they would have to confine themselves to travel along the pre-given road and highway system. Tactically speaking, drainage ditches that run alongside most roads and highways are quite formidable barriers. They are typically not that wide, but quite deep; more like narrow trenches than broad gullies. So they would not be wide enough for a typical 4x4 or 6x6 to be able to drive down into on one side, and then up out of on the other. The typical 4x4 or 6x6 would approach them and find that their first axle just drops in, bringing the vehicle to a shuddering halt.

Instead, these drainage ditches have to be crossed as per the illustrations already provided above of 8x8 trench-crossing. Or as per the video on the right, in which a MAN-KAT 8x8 crosses them with ease.


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Now in the world of RC models, I did find this gem: a replica of MAN KAT 8x8, crossing a "prepared" trench much like the one of the Tatra 8x8 crossing a concrete trench in an artificial "demonstration ground". Again, about 1 minute 45 seconds into the following video:



[video=youtube;v9bB1DCs2gk]https://www.youtube.com/watch?v=v9bB1DCs2gk [/video]


In both videos, the first of a model, and the second of a real vehicle, the problem is that they convey a rather "sanitized" picture of trench crossing. Because in both cases the trench is a perfect geometric construct, and the ground on either side of the trench is perfectly flat.

But just for reference purposes, here is a sequence of still-shots taken from the first video (the still shots from the second video were already posted on page 138, posts #1372 and #1373, at http://www.expeditionportal.com/for...igid-Torsion-Free-Frame?p=1852704#post1852704 and http://www.expeditionportal.com/for...igid-Torsion-Free-Frame?p=1852705#post1852705 ):



10 images





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7. RC Models of the Tatra 813 Chinese Six


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Although I could not find any videos of full-size Chinese Sixes crossing trenches, I did hit the "jackpot", so to speak, in terms of RC models. Inspired by the video above of an RC model MAN-KAT 8x8 crossing a trench, I began searching intensively for the equivalent for a 6x6, and the Tatra 813 Chinese Six in particular.

Turns out that there is a veritable cornucopia of videos documenting RC models that are miniature versions of the Tatra's "Ballast Tow Trailer". For whatever reason, this Tatra Chinese Six is considered "iconic", and it's a popular vehicle to model amongst RC enthusiasts.

The following are all videos featuring clips of RC models based on the Tatra 813 Chinese Six. In none of them does the Tatra RC model cross anything even remotely resembling a trench, but nevertheless these videos are great fun to watch. In the first ones the Tatra 813 6x6 appears right away; in the later ones, you kind of have to “search” ahead for the segments where it appears:






Although the RC model of the Tatra Chinese Six in the following video may at first seem a bit weird, because the chassis lacks a cab, it's actually in some ways more interesting precisely because one can see the wheels turn and the suspension move, as the model makes its way across varying terrain:



[video=youtube;p3ZuGVpwOgc]https://www.youtube.com/watch?v=p3ZuGVpwOgc&list=PLEWoaxZCukQkUGZF58MeN2ef 0Z-ivvuOy&index=9[/video]



Many of these RC models are quite large, 1:10 or 1:14 scale, so their physical behavior seems broadly realistic.


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Many of these models are also meticulously constructed, as documented in the following very beautiful video:






This video demonstrates the extraordinary level of craftsmanship and attention to detail that goes into constructing some of these, to the point where some even try to replicate the complex mechanical engineering of the Tatra backbone tube!!

Even more surprisingly, the following videos show Tatra 813 Chinese Six RC models re-enacting their original function as Ballast Tow Trucks: they pick up a heavy load (for instance, an RC model of a big excavator), and then drive around with it. The first video is about nothing but the Tatra 813 working as a Ballast Tow Truck, and this is immediately evident:






In the second video, the Tatra 813 Chinese Six appears about one minute in:






In the third video, the Tatra 813 Chinese Six appears about five mintues, 40 seconds in:







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9. A Superb Video: an RC-Model of a Tatra 813 "Chinese Six" crossing a Trench


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And now the big payoff: the following video features an RC model of a Tatra 813 Chinese Six crossing a trench, and behaving exactly as I predicted earlier, in post#1375 on page 138, at http://www.expeditionportal.com/foru...-Frame/page138 :



[video=youtube;voPQo54ajH8]https://www.youtube.com/watch?v=voPQo54ajH8&index=40&list=PLEWoaxZCukQkUGZ F58MeN2ef0Z-ivvuOy[/video]



Even though it's just a model, and so it's a bit artificial, it's a large model: 1:10 scale. Furthermore, unlike the sequence shown above of an RC model of an 8x8 MAN-KAT crossing a "sanitized" trench, this trench is much more realistic: it's rough, has sloping sides, it's muddy, and so on. The video is beautifully shot (for an amateur production), with sunlight silhouetting the RC model in a spectacular way as it crosses the trench. The video has also been posted in 720 HD, so it's not fuzzy, and one can make out all the detail one could ever want.

Because this sequence seems to me very important and illuminating, and because videos do "disappear" from YouTube, I've taken a great deal of time and trouble to put together a sequence of still shots documenting this trench crossing:











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Notice a few things in these images. For the first two axles clearing the trench is not a problem. They clear it just as successfully as the first pair of tandem axles on an 8x8. The trouble is the third axle. At one point the third axle even becomes airborne, and it hits the far side of the trench with quite a thud. But because the overall vector of the chassis is forward/upward, the two front axles are able to pull it of the trench, albeit with a bit of a struggle.

The contrast here will be with a more conventional tandem-axle-in-back format. In a more conventional 6x6 format, when the first single axle drops into the trench it will get stuck, and the whole vehicle will come to a shattering halt. In a more conventional 6x6, once the single front axle enters the trench the overall vector of the chassis is forward but downward, so additional forward motion is not going to solve the problem. The only solution might be to back out, because when backing out the motion of the vehicle will be backwards/upward.

I am probably not explaining myself all that well. For my earlier attempt at an explanation, see post #1375 on page 138 at http://www.expeditionportal.com/for...igid-Torsion-Free-Frame?p=1852708#post1852708 . There I wrote:

Note that even if [a conventional, tandem-axle-in-the-rear] 6x6 approaches a ditch with considerable momentum and speed, the minute the front axle drops into the ditch, the vehicle will come to a shattering stop. All the momentum of the vehicle will be transferred downwards, at an angle into the ditch.

Now imagine instead that a 6x6 with tandem-axles in front tries to cross the same trench. The first two axles are fine, and would merely duplicate the opening sequence we just saw above for the 8x8 Tatra 815, in post #1372. Once the third axle hits the trench, however, needless to say it drops right in.

However, if the trench is not too deep, then theoretically it seems at least possible that the 6x6 could still move forwards. The first two tandem axles would now be pulling the third axle up and out of the trench. And this might prove even more the case if one tries crossing the trench at considerable speed, with lots of forward momentum. Yes, when the third axle at the back of the vehicle hits the trench and drops down, the "bump" will be incredibly jarring. But with enough forward momentum, and with the rest of the vehicle's mass continuing to go forwards and now angled upwards, there might be enough force to pull the third axle up and out of the ditch or trench.

Put technically, the lines of force in a 6x6 with tandem axles forward seem to be theoretically more “favorable” to trench-crossing (within limits), than the lines of force in a conventional 6x6. The conventional 6x6 might be able to back out of a bad “front axle stuck in a trench” situation, but it can't go forward. Whereas a 6x6 with tandem-axles up front wants to go forward, in order to get out of a bad situation in which its trailing single axle gets caught in a trench.

I am just wildly speculating here, so what I just wrote may be completely wrong-headed......

If this video of a 1:10 scale model of a Tatra 813 is anything to go by, my speculation was right on track. This RC scale model does exactly what I predicted a Chinese Six should do when crossing a trench.

Now granted, one might not want to risk a large 6x6 expedition vehicle with an expensive camper pulling off stunts like this. But it's easy to imagine situations in which the TerraLiner is confronted not so much by a man-made, very deep-cut ditch or trench, but rather, is confronted by a much less dramatic and less deep gully caused by erosion. The way things work out geometrically, it seems that a Chinese Six would also be much better at crossing shallower gullies than a conventional 6x6. All the lines of force would be in favor of the Chinese Six, whereas a conventional 6x6 is in effect working "against" the terrain, almost literally trying to dig itself into a ditch.

If anyone ever reads this who has experience driving Tatra 813 Chinese 6x6's in truck trials, and understands experientially and intuitively what I am trying to illustrate, PLEASE POST!!!

It would be great to get some real-world feedback from people who have direct personal experience of the difference in handling characteristics between a conventional 6x6, versus a Chinese 6x6. Everything I know about physics, all of my "spatial intuition" as a sculptor and a driver, as well as the video posted just above, suggest to me that a Chinese 6x6 is a vastly superior axle-format for bad-road and off-road driving. That's why I seized on it with such gusto when thjakits posted the images of the Kamaz Typhoon. Something suddenly "clicked", and I realized all the ways in which having two steerable axles up front would be a vast improvement. But again, what I've been discussing here is purely theoretical, and it would be great to either see a video of a Tatra 813 Chinese Six in action, crossing a troublesome gully at high speed; and/or see videos that demonstrate other superior handling characteristics of the Chinese Six in bad-road/off-road contexts; and/or actually hear from someone with practical hands-on experience, who could discuss the issue.



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10. Some more RC Models of the Tatra 813 Chinese Six Crossing Trenches


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Now I also came across some more videos of a slightly less "realistic-looking" RC models, but also quite large, again 1:10 scale. Here too there are some sequences that nicely illuminate what crossing gullies or trenches might be like for a Tatra 813 Chinese Six. In the first video, skip ahead to about 3 minutes, 25 seconds:






In the second video, skip ahead to 5 minutes, 18 seconds:



[video=youtube;8O8IjeLGAn4]https://www.youtube.com/watch?v=8O8IjeLGAn4 [/video]



This second video nicely illustrates how much harder trench-crossing or ditch-crossing would be when the lead up to the ditch is already downward sloping terrain.

In the third video, skip ahead to 5 minutes, 10 seconds:






Further along in the thread I will post sequences of still shots taken from these videos, too, again just in case these videos ever disappear from the web.



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11. Some Closing Videos


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Thought I'd finish this particular series with some especially “instructive” videos, videos that I came across in the course of my search for videos of trench-crossing Chinese Sixes. The first is a very complete video about the conventionally figured Tatra 815 6x6 military truck – see http://www.military-today.com/trucks/atc_6x6.htm :



[video=youtube;qYQbe3ImRug]https://www.youtube.com/watch?v=qYQbe3ImRug&index=36&list=PLEWoaxZCukQkUGZ F58MeN2ef0Z-ivvuOy[/video]



This video is packed with action, but alas, no trench crossing…..

And yet this is as one might expect, because a conventionally configured 6x6 can't really cross a trench. Also see the wide-ranging Tatra “six wheeler” YouTube playlist at https://www.youtube.com/playlist?list=PLEWoaxZCukQkUGZF58MeN2ef0Z-ivvuOy .

And here is a rather incredible video of a Tatra 813 6x6 Chinese Six bombing through lots of deep snow; I haven't seen another video on the web quite like it:






About 7 minutes, 40 seconds into the video the Tatra dives in and out of what appears to be a sequence of two or three ditches. It's difficult to know exactly what is going on, because the snow is so deep. Notice in these videos how the SUVs don't handle gullies well at all. They just dive in nose first, and then get stuck, because all the force when going forward is also going downwards. They can only get out by reversing. Thought I'd finish with this video, because once again it demonstrates the formidable handling capabilities of a Chinese Six.

All best wishes,



Biotect



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REQUEST

Again: Please do not quote the previous series of posts until this message has been removed


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[Haf-E]

I think one detail missed on the "chinese six" configuration when used on a 6x6 vehicle is that with the dual steering axles an inter-axle differential is necessary - while with the traditional single steering axle the back two axles do not include an inter-axle differential. This reduces the cost and complexity involved.

Most of the older trucks where not 6x6 but just had the single rear drive axle powered. Adding a second front steering axle was an inexpensive way to increase the payload capacity since it is not a powered axles. Since each of the four front wheels is allowed to rotate as required, tire scrubbing is minimized compared to having a tandem rear drive axle setup which will scrub tires since only cross axle differentials are included.

If the vehicle is designed for low traction surfaces only (like a truck trials rig or a snow rig) then the benefit of the dual steering axles would be substantial and a inter-axle differential is not needed (or even perhaps desirable).

I think that Tatra's include interaxle differentials between the two forward and the two rear axles - not sure what is done on a MAN type truck - anyone know if they are different?

 

[thjakits]

CAMPO!

My sincer apologies!! For some reason I thought it was YOU who posted the "Orange Nightmare"!

....it was actually BIO himself who threw that low-ball...:wings:


Cheers,

thjakits

 

[thjakits]

I think one detail missed on the "chinese six" configuration when used on a 6x6 vehicle is that with the dual steering axles an inter-axle differential is necessary - while with the traditional single steering axle the back two axles do not include an inter-axle differential. This reduces the cost and complexity involved.

Most of the older trucks where not 6x6 but just had the single rear drive axle powered. Adding a second front steering axle was an inexpensive way to increase the payload capacity since it is not a powered axles. Since each of the four front wheels is allowed to rotate as required, tire scrubbing is minimized compared to having a tandem rear drive axle setup which will scrub tires since only cross axle differentials are included.

If the vehicle is designed for low traction surfaces only (like a truck trials rig or a snow rig) then the benefit of the dual steering axles would be substantial and a inter-axle differential is not needed (or even perhaps desirable).

I think that Tatra's include interaxle differentials between the two forward and the two rear axles - not sure what is done on a MAN type truck - anyone know if they are different?

.....well, most of that won't be a "problem" - IF the terraliner uses separate e-motors for each wheel or even only every seperate axle....

thjakits

PS: Bio, NO I don't have Chinese-6 experience, but I DO have a little tandem-rear drive experience (2 drive axles, fully lockable, Heavy Load transport).
Under the right "wrong" conditions, it can push you right of the road! Under normal conditions (perfect traction) it WILL torture ALL your tires, mostly the front ones, but a RIGID rear tandem will twist itself into a tire shredding, power-eating nightmare. Imagine 20 tons on a dual-drive-tandem with 8 wheels. axle to axle a bit over a meter at full steering lock (front axle) - NO rear steering (active or passive) - basically EACH tire is working against each other tire.
You need a LOT more power once you get into that kind of situation, just to burn it up sliding rubber across the tarmac!!
NO need for specific Chinese-6 experience - common sense and design analysis will do just fine to realize that 2 front steering axles is a LOT better than anything else.
I don't think the KAMAZ Typhoon is a one purpose only vehicle. Russians do not tend to make single purpose stuff for the military.
There is already TWO versions of the Typhoon and I bet sooner or later you will see a 4-axle transport version!

That you don't see that many Chinese-6 anymore in general transport is PURE economy (penny pinching....)
[The Austrian Crane tractors are special purpose builds, most likely because a tandem rear drive rig would be too long for the purpose - (to get the Crane further back and axle loads into check) - so the sensible thing is getting another axle up front, which gives them 20 tons technically and 16 tons legally on that end ... or too short for a regular rear tandem to support a cargo platform and still get the front axle weight into legal limits....]

Even on the common long distance over-the-road trucks, it would not matter if you had 2 rear axles or 2 front steerers. There it is more a road-legal matter.
Max axle numbers allowed, Max axle weights allowed, Max STEERING axle weights vs. DRIVE/LOAD axle weights allowed, etc...
Compare the TYPICAL US/OZ tractor trailer configuration vs. the TYPICAL EU-configuration. Tractor power levels, cargo weights and GVW are pretty much in the same ball-park. Configurations are totally different (US/OZ: 3-axle tractor, tandem dual-rear drive, trailer with 2/3 axles at the end of the trailer, still mostly with dual wheels; EU: 2-axle tractor, 3axle trailer - with the trailer axles moved way under the cargo, single wheels)
What do I get at? I think your weight-distribution theory is not entirely accurate. Look at the Typhoons (Kamaz and Ural) Kamaz has the tandem rear quite a bit more forward to support the same weight. Kamaz puts the axles at the outer ends of the load-area and the front axles carry most of the power unit on both....

I think LOAD distribution is NOT a primary factor for a decision pro/con Chinese-6. Especially for Terraliner, as you still can move things around at will.
If you must use a rear tandem configuration, at least do yourself a favor and use one steering axle there to at least eliminate "pushing" .....
[I don't think that the commonly referred to Mercedes Luxury RV rear tandem has a steered rear axle.....]

On any "Truck turned RV", load distribution tends to be rather low priority (over functionality), as the resulting RV mostly ends up being WAY lighter than the original truck - to the tune to be able to convert to single wheel and having to slim the springing [ ...maybe except for the light delivery truck turned expedition rig]

Mostly you DO NOT want to be at the axle load limits for a rig like the Terraliner - mainly because you want some reserve for the situations, where you have most off the total load on ONE axle and nearly NOTHING on the others....NOT a common situation on most over-the-road tractors......[more so on Expo Rigs]
What was your projected GVW? 14-16 tons?? WHY would you actually need 3 axles?? (with 8-ton and 10-ton limits on axles you really only NEED 2 and even have some spare...., what you really WANT though is 3 axles!)
See - LOAD considerations are not the real matter here - OFF-road-ability IS!

One design-point you might want to aim for is: MAX OFF-road-ability! NOT to actually do off-road, but to have the extra-abilities to avoid BAD ROAD-hassles when you encounter them!
"Better be able to just switch in AWD and just power through the "hassle", than having to rig a cable, unload everything and hopefully wiggle your way through with you ROAD truck...."

As you demonstrated in your list of "Most dangerous roads" - the actual road conditions mostly do not need even AWD or lots of articulation or even OFF-road tires. Most of the dangers arise from sides that you have not much of a way to DESIGN for and around:
Weather, lack of rails and/or road maintenance, lack of common sense and stupid people!
[Well, the Strada delle 52 gallerie is just a little tight for a Terraliner, but the actual road condition is fine! If you are nuts enough, take a Subaru on Street tires and go for it.....]

Generally it is more like flooded roads, river crossings, landslides on roads you will need to deal with.
Generally you will scout if your rig FITS a track for size or not....

[Just so happened I was a passenger on one of those "Most Dangerous Roads" last Tuesday - Quillabamba to Cusco in Peru - no joke, it is dangerous!
Our "Expo"-Vehicle? A stock Toyota Yaris!! (My relieve searched for this specific one for over an hour! This one had 4 decent tires! Most others have 1/2 decent ones on the front and junk at the rear!)
The road? 2-lane blacktop (for most of the distance in excellent condition)!
Dangers?
- Mostly NO safety rails - go over the edge and nearly free-fall to the road below or until you hit the river below....you'll have time to finish your prayer...
- Stupid people overtaking in blind turns!
- Stupid people NOT waiting for the trucks of a convoy to pass, even though they have a forward and trailing guide car warning and advising...
(Curves are way to tight for a 60 ton rig to stay on their lane only)
- Tourists on bicycles doing downhill and getting scared and out of control! .....actually these are arranged tours, with mini-buses trucking people up to the top with a trailer full of bikes in tow - .....one of them did the "passing a truck in a blind spot" stunt!!
- Fog, Clouds at least near the top (13400 feet)
- FORGET IT at night!!

Note to myself: I want a BIG bumper to be able to deal with those stupid people with the least damage to my own rig! Pulling over/out is NOT an option!]



EGN: Was it your buddy who cut the last axle off a MAN 8x8? Any chance you could ask him to chime in here?
Not many Chinese-6 guys around anymore, .....these days!



Fire away! eepwall:

 

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Most of the older trucks were not 6x6 but just had the single rear drive axle powered. Adding a second front steering axle was an inexpensive way to increase the payload capacity since it is not a powered axles. Since each of the four front wheels is allowed to rotate as required, tire scrubbing is minimized compared to having a tandem rear drive axle setup which will scrub tires since only cross axle differentials are included.

If the vehicle is designed for low traction surfaces only (like a truck trials rig or a snow rig) then the benefit of the dual steering axles would be substantial and a inter-axle differential is not needed (or even perhaps desirable).

I think that Tatra's include interaxle differentials between the two forward and the two rear axles - not sure what is done on a MAN type truck - anyone know if they are different?

Hi Haf-E,

Good to hear from you. Yes, this was one of the points made on the "Chinese Six" discussion board on Trucknet, at http://www.trucknetuk.com/phpBB/viewtopic.php?f=35&t=34478 : that the Chinese Six arrangement was a cheap way to increase a vehicle's payload allowance.

For my potted summary of the main points made in that Trucknet discussion, see post #1392 at http://www.expeditionportal.com/for...edition-RV-w-Rigid-Torsion-Free-Frame/page140 (standard ExPo pagination). See points (6) and (7) in particular.

Very interesting observation about the differentials, and an excellent question that you put to egn. Hope that egn is reading and might know the answer!


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1. egn's Friend and the “Castrated” MAN-KAT


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So too, Thjakits: it was in part because egn early on suggested that I might want to begin thinking about a Chinese Six arrangement, that when you posted about the Kamaz Typhoon, everything finally "clicked". But also granted, prior to campo's "aggressive" intervention, I was still thinking in a very banal way about simply taking the Tatra 815's pre-manufactured backbone tube and hence, axle configuration; or the pre-manufactured ladder frame of a MAN SX-44; and then simply sticking a fully integrated box on top of that. Recall that campo and perhaps yourself, quite strongly suggested that I was wimping out: that the ideal TerraLiner should be designed completely "from the ground up", and would have a "vertically integrated" space frame construction, perhaps even semi-monocoque, as per the coaches made by Newell and Prevost.

Now that I've given myself that degree of design freedom, the logical next step was to ask whether the traditional 6x6 axle configuration is truly optimal, for an expedition motorhome specifically. The traditional 6x6 axle configuration may be optimal for other vehicle types, but for an expedition motorhome?

The "engine weight-distribution" issue that originally motivated egn's suggestion that I think about a Chinese Six, is no longer such a big concern now, given that the TerraLiner will be a hybrid diesel-electric. But as you suggest, Thajakits, it would be great to hear from egn's friend who owns a "castrated" 8x8 MAN-KAT, a friend who egn first mentioned in post #135, at http://www.expeditionportal.com/for...pedition-RV-w-Rigid-Torsion-Free-Frame/page14 . Here is the friend's castrated MAN-KAT:





It would be great to know why egn's friend chose to buy a MAN-KAT 8x8 and then castrate it, so as to achieve a Chinese Six axle configuration? Instead he could have bought just a regular MAN-KAT 6x6, of the kind owned by egn. Or he could have bought a Tatra 813 Chinese Six "Ballast Tow Tractor" off-the-shelf, in effect pre-castrated, so to speak:





Perhaps egn's friend has photos and/or a video of his Chinese Six dealing with the "standard" kinds of obstacles one might encounter when bad-road driving, obstacles like trenches, gullies, ditches, washed out roads, etc.???



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2. Comparative Trench Crossing with a Chinese Six


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Thjakits: You may or may not be right that load distribution is perhaps not so critical re pro/con Chinese-6, especially in expedition motorhomes that simply take a very heavy "base chassis", like a MAN TGS 6x6, and then stick a very light-weight motorhome body on top, a body made of fiberglass composite panels. But egn seemed to think that proper weight distribution was still important, especially when it comes to placement of things like water tanks, food stores, etc. In the case of Blue Thunder, egn was beginning with a comparatively heavy MAN-KAT 6x6 chassis, on top of which Enfatec mounted the standard light-weight fiberglass box -- see http://www.enfatec.de/index.php?id=54 .

Very interesting observations about how the wheels on a rear tandem axle "work against each other", and the vast superiority of the Chinese Six in this respect. Another good reason for favoring the Chinese six.....

As for gross tonnage, I am afraid we are still in three-axle territory, at roughly 20,000 kg.

Furthermore, if you have been reading my thoughts about trench-crossing, you'll see that I would want three axles in any case, with two in tandem up front, because I have a very strong suspicion that another major bonus of the Chinese Six is that it allows the first part of trench crossing to resemble the trench-crossing of an 8x8. Of course, once the third axle hits the trench, the rear of the Chinese Six will dive right in. But perhaps with enough forward momentum that rear axle could instead more or less "jump" the trench?

One could first approach the trench slowly, with the first two tandem axles in front clearing the trench, as per the 8x8's in the videos in posts #1372 - #1375 on page 138 at http://www.expeditionportal.com/for...edition-RV-w-Rigid-Torsion-Free-Frame/page138 , and post #1415 on page 142 at http://www.expeditionportal.com/for...edition-RV-w-Rigid-Torsion-Free-Frame/page142 . Once the first two axles clear, then perhaps just gun the engine and hope that the rear axle "hops" most of the trench, and does not hit the far wall of the trench with too much of a jolt......:sombrero:

I really need to see a video of a Chinese Six trying to clear a trench in exactly this way! Either a Kamaz Typhoon, or a Tatra 813 6x6 "Ballast Tow Tractor"......:jumping:


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3. The Human Factor in “Bad Roads”


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Excellent observation about the most important factors that make really bad roads, bad. Not actual road conditions, but rather:

Weather, lack of rails and/or road maintenance, lack of common sense and stupid people!

I've lived for years in Third World countries, especially Latin ones + India. The "kamikazee death-wish" driving styles of some of the people in these countries always amazed me. When you're on a jam-packed bus in the middle of nowhere, and the driver flies along as if Krishna is his co-pilot and will protect him from all harm, you find yourself "rationalizing" overtime to quench the fear. You reason,

"Hey, this guy must know what he's doing when he takes those blind corners at such high speeds. After all, he drives these roads every day!! And he's still alive, and seems to be a middle-aged guy, with a wife and kids!! He must want to live just as much as I do! So stop worrying.....”

Except that one should worry. This driver is tempting Krishna, and he has forgotten that in the Mahabharata Krishna is no friend of those who have a weakness for gambling, especially when they gamble with the lives of others:










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See http://www.telegraph.co.uk/news/wor...rash-in-northern-India-kills-11-tourists.html , http://www.nydailynews.com/news/world/buses-plunge-indian-mountain-gorges-21-dead-article-1.1832479 , http://www.brecorder.com/top-news/1...epal-bus-crash-kills-38-pilgrims-police-.html , http://www.indiatvnews.com/news/ind...us-falls-into-ditch-in-uttarakhand-17195.html , http://himachalwatcher.com/2014/11/...-injured-as-bus-rolls-down-a-700-meter-gorge/ , http://www.deccanchronicle.com/141124/world-neighbours/article/nepal-bus-crash-death-toll-reaches-47 , http://hillpost.in/tag/accident/ , http://hillpost.in/2014/04/18-dead-47-injured-in-himachal-bus-accident/98483/ , http://hillpost.in/2010/01/seven-delhi-residents-killed-in-himachal-road-accident/17985/ , http://hillpost.in/2010/11/bus-accident-in-chamba-killed-1-child-injured-35-persons/22960/ , etc. etc. ; http://accidentsinindia.blogspot.com/2013/09/india-31-killed-as-bus-plunges-into.html , http://accidentsinindia.blogspot.com/2013/09/meghalaya-18-killed-in-bus-accident.html , http://accidentsinindia.blogspot.com/2013/09/52-killed-46-injured-as-bus-falls-into.html , http://accidentsinindia.blogspot.come/2013/08/12-dead-in-himachal-bus-accident-at.html , etc. etc. ; http://www.haaretz.com/news/world/1.622566 , http://www.dawn.com/news/1077707 , http://www.israelnationalnews.com/News/News.aspx/186547#.VXI07UtxBsg , http://www.kosherpress.com/8-die-in-nepal-bus-crash-4-israelis-may-have-been-on-board/ , http://www.timesofisrael.com/one-of-two-israeli-victims-of-fatal-nepal-bus-crash-named/ , http://silverbirdtv.com/news/7536-nepal-bus-crash-death-toll-reaches-47 , http://www.titanherald.com/2014/06/17/bus-crash-in-northern-india-kills-11-tourists/ , and http://m.tengrinews.kz/en/emergencies/Bus-crash-in-northern-India-kills-11-tourists-254246 .



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4. What are the Most Dangerous Countries to Drive?


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Here is one study's mapping of the top 25 countries worldwide for road fatalities per population:





See http://www.theatlantic.com/internat...-most-dangerous-countries-for-drivers/283886/ or http://www.moneysupermarket.com/car...ve-of-your-life-road-safety-around-the-world/ .

And here is an even more sophisticated, detailed map that does much the same, mapping road fatalities per 100,000:





See http://roadskillmap.com and http://www.dailymail.co.uk/news/art...eople-die-traffic-related-accidents-year.html . If you go to the website, the map is interactive and "zoom-able".

But I am not sure if this is the best way to gauge comparative road safety, because some countries are more developed and have many more cars per capita, whereas a comparatively underdeveloped country with much fewer cars per capita may seem "safe" in terms of fatalities per population, when in fact it is not. It just has fewer cars, hence fewer automotive fatalities per 100,000 people. The more relevant figure would seem to be fatalities per km driven, a figure that gauges the number of fatalities relative to the actual amount of driving that goes on.

There is such a map:





Unfortunately, it only covers road fatalities per vehicle-km in developed countries.

Furthermore, in the first map above, the countries are mostly Third World, and so I suspect that what the map is really recording is the percentage of road fatalities in comparison, say, to fatalities from cancer. But in most Third World countries, comparatively few people die of cancer, because they don't live long enough in any case. So a greater percentage will register as dying from road accidents. But this does not necessarily mean that the roads are more dangerous.

In other words, it's not really clear to me what these maps actually measure, and how relevant their statistical metric is to actual road safety.

The following map uses the same metric as the first two maps above, road fatalities per 100,000 population, but presents a slightly different picture:





See http://en.wikipedia.org/wiki/Traffic_collision . Many of the “top 25” countries for road fatalities per 100,000 in the first map shown above, are clearly not top of the list on this map – for instance, Malaysia, Venezuela, Namibia, etc.

The following map illustrates the 10 countries that account for roughly half of all fatal car accidents worldwide per year -- 600,000, out of 1.3 million per annum in total:





See http://www.washingtonpost.com/blogs...-countries-that-have-the-most-traffic-deaths/ . These are also some of the largest countries on earth in terms of population, so one could claim that the map is very "skewed" in this respect. For instance, India currently leads the world in the absolute total number of traffic fatalities per year, but India is also a very big country in term of population, with 1.252 billion people -- see http://timesofindia.indiatimes.com/...-in-2011/articleshow/13912980.cms?referral=PM . So it's perhaps not surprising that India should lead. What matters, rather, is the ratio of road fatalities to population, or even better, road fatalities to vehicle-km driven.

With that said, however, even though low and middle-income countries account for about 48 percent of the world's vehicles, they account for more than 90 percent of the world's road traffic fatalities -- see http://www.mikebloomberg.com/conten...Worldwide_Movement_to_Improve_Road_Safety.pdf . Put in those terms, they really are more dangerous places to drive than First World countries.

I was a bit surprised to learn that in India, the highest number of accidents and road fatalities per 100,000 population occur in the less mountainous south; and that the most mountainous northern regions are some of the safest:



. ..


See http://www.ibnlive.com/news/auto/road-accident-map-of-india-2-1000681.html .

There's also some consolation in knowing that one is probabilistically speaking much less likely to get killed driving a car, than driving a motorbike -- see http://www.bbc.co.uk/news/uk-15975564 . One is roughly 12 times as likely to die driving a motorbike, as driving a car; and 121 times as likely to die driving a motorbike, as driving in a bus or coach:



...



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5. Back to Chinese Sixes


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So returning to TerraLiner design, very much agree that the biggest issue may not be the ability of the TerraLiner to handle the overall quality of bad roads “in general”, but rather, the TerraLiner's ability to deal with particular kinds of roadway degradation in specific locations: as you suggest, floods, river crossings, landslides, etc.

Which, again, is why your post about the Kamaz Typhoon sparked such a sudden wave of interest, and why I now so obsessed with learning more about the Chinese Sixes!!

All best wishes,



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[thjakits]

Thjakits: You may or may not be right that load distribution is perhaps not so critical re pro/con Chinese-6, especially in expedition motorhomes that simply take a very heavy "base chassis", like a MAN TGS 6x6, and then stick a very light-weight motorhome body on top, a body made of fiberglass composite panels. But egn seemed to think that proper weight distribution was still important, especially when it comes to placement of things like water tanks, food stores, etc. In the case of Blue Thunder, egn was beginning with a comparatively heavy MAN-KAT 6x6 chassis, on top of which Enfatec mounted the standard light-weight fiberglass box -- see http://www.enfatec.de/index.php?id=54 .

PROBABLY expressed myself wrong:

Weight Distribution is going to be VERY important to maximize performance!
HOWEVER in your present design-phase it should not matter at all - 1st decide on the best axle/steering/suspension configuration for your purpose, THEN distribute the weights to perfection [simple said: 1st heavy stuff as low and central as possible, then start to fit the lighter stuff around this - simple said - HARD to do :sombrero:!!]

The problem in India seems to be that EVERYONE trusts their live to that KRISHNA guy - with the amount of road stupidity prevailing over there - he must be pretty tired watching out for the dumb! I guess he slips into a nap now and then - of course the stupid will take the opportunity and mess things up immediately! :littlefriend:

Now, if they could be convinced to switch to Catholic Christian believes, they wouldn't depend on one guy only:
...the Lord himself, Jesus (....from "************************!! Watch out you mor**!"), Holy Spirit, Virgin Mary, a LOAD of Saints, squadrons of Guardian Angels and all your dear past away relatives, you can call up to give you a hand "just THAT one time!" (...never mind that you called them up "THAT one time" about 25 times already!)

So - IF you ever get into one of THOSE situations and you are not sure about your religious affiliation - I wholeheartedly recommend Catholic Christian tendencies - ...it's just a smarter system! - lots of workload sharing .....more quality "*** saving"......

[NO joke - over the years in my career in the skies, I got myself into a few of THOSE situations - .....I got more catholic than the POPE himself in a hurry!! ..... a few times over! :REExeSwimmingHL: ......worked EVERY time!!]


Back to Terraliner/Typhoon - you might want your chassis/frame guys have try to get a word with the Kamaz guys - they for sure could tell you all about the pro/contra of Chinese-6!! As it seems, that now you actually get to built the thing after all - axle configuration will be a very important decision!
The Kamaz Typhoon being a brand new development - Chinese-6 seems to have some serious merits - especially as the Typhoon is fairly close to the Terraliner Mobility Requirements and probably final weights - even though the missions and equipments are totally different....
[Haven't seen a trench crossing of the Kamaz Typhoon yet - probably still classified...]

To Obstacle crossings in offroad - please do NOT GUN it on the SINGLE axle!! All you going to do is hammer/kill that axle!

You don't see in any of the demos axles getting slammed into edges - you smooth up to it and try to crawl first, if this doesn't work you might want to gun it and hope the other axles purchase some grip. Only after that you back off a little, and try a "dynamic nudge" .....as long as the impact is absorbed by the tires....
What you propose might work on the short Typhoon, if the loads are right, but not on the long one (and Terraliner would/will be even longer)...

...we are talking trench crossing, bolder crossings, steps, etc. - soft ground, mud, sand, etc. is a different story!! ...

Remember the 1st off-road rule: "As slow as possible - as fast as necessary!" - .....you want to approach the "fast" part slowly! :chef:


ENG's friend Chinese-6 MAN KAT is probably not the best benchmark for the Terraliner - it seems it is a competition rig with a very light rear end and forward weight bias - On the Terraliner you might want to put somewhat more weight to the back of the truck.....

STILL, I REALLY would like to hear ENG's buddy chime in here!! Hopefully with a few video clips too!

His approach angle is a lot better than the old Tatras'!!

Cheers,

thjakits