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

[thjakits]

Reloaded - ready to shot ....from the hip .....again::costumed-smiley-007

Hey Bio!


EDIT: I am just catching up on the posts made while I was working on this one - so there is quite a bit redundant answering going on below....
Just ignore what is already answered!!
...EDIT End

I find myself being convinced in favor of straight axles, and no IS.

So unless I hear some really convincing counter-arguments soon, ...., as to why IS is still preferred to straight axle,...

I need the other side to make a really good, summary, point-form case for IS.

That is exactly where I am - CERTAINLY you can do a workable IS or Trailing Arm Suspension or ... - BUT for me, the SA is the BEST choice for THIS application (for reasons multiple times stated....) - convince me that IS (or any other system for that matter) has at least ONE advantage over SA WITHOUT also causing some detriment....

I am NOT against IS at all - however in this application it is NOT the BEST solution (...in my book)

[This is how I do MOST of my decision making when it comes to this kind of questions - I ALWAYS "question" a proposed solution, I try to bring it down!! When we get to the point where I have no more argument against - it must be alright! I encourage the IS proponents to do the same from their point of view: Argue WHY SA is no good and WHY IS is better - who knows you may convince me after all! It is NOT that I am always right!! BUT one settles on a certain solution by empiric experience, research, observation, etc.... - so now convince me that I am wrong after all....as long as the arguments stay focused, there is no better way to find the OPTIMAL solution, then by eliminating discussable alternatives]

The TerraLiner will be full serial hybrid, not parallel; with 6 separate electric hub motors, as per Haf-E’s recommendation. It will be 10 m long, and 20 tons, so just stipulate a power size for the electric hub motors, and the power requirement of the generator should be easy enough to calculate?

Answer:

A word to your power requirements:

I know Camo wants 500hp for his rig!! I tell you that is WAY TOO much for a 2-axle rig!
You really will never NEED that power! Camo might feel the need, because of his auto/semi-auto set-up. That's one item I certainly DON'T like on a Explorer Rig. Perfect for Long Distance Road Transport, but in a OFFroad/DIRTroad situation I'd rather have personal control over ALL my power and ALL my gears!!
If you have 500hp available it is just too easy to guzzle fuel (no matter if your final drive is electric - if you use 450kw you need to provide it - be it directly form the Diesel engine or via a generator...) - also it is very easy to break something if you don't use the power properly!

Figure it out: WHAT is your possible longest, steepest, straight (or max speed - take 85-90 km/h) climb you imagine (something like the Brenner Pass between Austria/Italy or similar stuff in the Rockies or the Himalayas) - WHAT power do you need to accelerate to and maintain that speed at MVGW with an additional 30 kt headwind/rain and pulling your trailer with your favorite toys anywhere on that slope? THAT's the max CONTINOUS power you need.....

A 42-ton 18-wheeler will not need the 500-600 hp they got today to maintain that - why would you at 1/2 the weight??

A 300KW power unit with a serious battery bank and 420KW capability on the wheels should make you a POWER-house/macho Truck amongst all of them out there!! ...and this unit should be efficient enough down at the max level you can pump into the battery bank when charging only....

....the

"possible longest, steepest, straight (or max speed - take 85-90 km/h) climb you imagine"-part

....is EXACTLY where you are running on the power unit ONLY - battery is discharged by now.

120 KW will be on the very edge - .....remember, you might not just look at the Terraliner max weight, but also at the possible "toy shop" getting pulled along! Certainly another few tons!

...with 6 separate electric hub motors, as per Haf-E’s recommendation....

...certainly a beautiful solution (IF you can get motors as I posted recently...) - STILL, you should consider OPTIMUSP's recommendation of a single big motor per axle OR a hybrid of both, with ONE BIGGER MAIN-drive motor to the main drive axle (most likely the rear axle) and hub-motors at the other 2 axles.

a) It probably is easier to lock axles with a mechanical locker than with a "electronic" locker [Electronics managing the amount of torque/power each wheel receives...it still is hard for electronics to decide, when a wheel lost traction or is slipping. Most 4x4s with traction control still have a button to switch it all off, so you CAN spin the wheel for certain situations] Still, it would make sense to have 1 main drive axle and 2 "auxiliary axles" - after all, whether we (and/or your client) like it or not - most Terraliners would/will spend 90% of their driving on "car drivable" roads.

b) Though not as important as for a Longhaul Transport - 6 smaller motors are still way less efficient than 1 big motor [Your electric drive engineer friends need to whip out their sliderulers !!]

It will be 10 m long, and 20 tons...

I see, we .....got past the 16-ton goal by now! Now you say 10 m. IF you space the axles evenly you will have a max center to center distance of around 2.6m (if you manage to the keep the front/rear overhang to 0.5m) - rather excellent for the intended purpose.
If you increase to the legal limit (12m) you STILL can maintain 3m but gain a solid 2m for "stuff"

At least conceed (yourself) a modular approach to the project, where you can have a whole line of basic-structures, that can take any and all modules you fit:

Basic frames from 8m to 12m (in 1m increments) - designed and calculated so that the 12m version will do anything asked.
Then just build the shorter frames accordingly.

SAME axles
SAME power unit
SAME bathroom modules
SAME bedroom modules
SAME bunk modules
SAME fluid storage modules
SAME dry storage modules
SAME environmental control modules
SAME kitchen modules
etc....

- Have a few moduls for each section available and your customer can "build" his own Terraliner.

Face it - customers that will be able to afford a Terraliner will be rather specific about what they want in their unit - certainly not going to be people that take to the "Take it or leave it" choice.....
(...you can do that with a budget-camper-trailer, ....and even there you will have "options")

The TerraLiner will also carry a supplementary 20 KW turbocharged generator. But not to act as "backup" for the main engine-generator. But rather, to charge the batteries efficiently and quietly when parked, as suggested earlier in the thread.

Again, as discussed before:
IF you already have a Power unit to EXCLUSIVELY produce electric power (.....AND hydraulic pressure, AND air pressure) - the goal should be to get a big enough (and quick enough) battery bank, to be able to charge it at the lowest EFFICIENT power level the Power Unit can run.
I suggest that you start your Power requirement calculations around a 220-280KW unit (that should cover your max continous requirements without battery assist). From here - see what is the lowest power output you can produce ECONOMICALLY - my wild guess: this is around 1/3-1/4 rated power, below that your fuel-efficiency will start to suffer. So, now you need to get your batterypack and charging capability designed in a way, that these can take 50-70 KW of charging. I suppose a batterypack this size will need at least an hour to charge up, so your engine will get a good run (heating water in the process) and the charged pack should be able to keep up and running for at least 24-36 hrs.....
NO need for a 20KW unit - remember, the smaller a unit, the more UN-efficient they become (unfortunately - same game as with the e-motors!!)

[Nothing wrong with a 20KW-aux unit, but if you DO NOT need one - it is a LOT of space that can be used for other stuff!]

NOISE: You can encase the big unit in a way so you hardly can hear it at full song!! Not a problem anymore today! The smaller 20-KW unit is most likely noisier!!
[For me, part of the attraction IS the noise a Turbo Diesel Truck engine emits at power - you can "feel" the power! Hearing a turbo whistle as it comes on pressure gives me goosebumps - 2nd best music after a turbine starting up!!
Now for a Serial hybrid - FORGET about it! Even if you can hear the engine, it will most likely always be out of synch with the actual driving experience, as the power flow will be buffered through the battery bank. E.g. You step on the accelerator and get an immediate push in the back and MOVE forward - a few seconds behind, the engine starts to rev up and push KWs back into the battery bank and directly to the drive motor(s). You lift the accelerator and start to coast - engine is still at power as the battery bank is still not recharged to nominal.....Most likely this would be a very unusual and distracting experience, based on "normal" cars/trucks sound "behaviour" of today. Actually I believe it would be advisable to eliminate as much Diesel-Generator noise as possible!!]

As it is, you can design the whole unit so, that you literally only have to plug in a power plug and control unit connection!

So a Unit Change should be over in less than 10 min!! Open Power-unit cover (if in the front - lay down Bullbar) - slide out - disconnect plugs - lift off - new unit lift on - connect plugs - PLAY! - everything running and charging? :victory: - slide in - lock up - LOCKED AND LOADED!! 10 min, no sweat.
[Going extreme, you could even provide a crane/jack to lower and lift the unit yourself. Many times you might not have a forklift or similar available, but you always should be able to get a crate directly besides the truck (or in front or wherever you have the power unit)]


PORTALS: I agree - the size truck Terraliner (TL) will be - not needed

AXLE LOCATION: ?? Are you saying you now want to adopt a 1 FRONT and 1 TANDEM REAR configuration???

Now - I NEVER saw a rig as long as the Terraliner -10m - with equally spaced axles - only ZETROS-like configuration...
[...or 8 wheels - scout tanks - military, but they are as long as the vehicle gets with wheel spacing as tight as possible....]

You/we will need to think thoroughly HOW the Terraliner will act when going over a steep ridge:
...as it is - there WILL be some serious sew-saw action at some point!! Question is WHERE will it dip over?
Between the front and middle? Middle and rear? Where is the center of mass?
Maybe - analyzing this scenario will suggest to abandon the equally spaced axles and push more towards a 1+2 or 2+1 configuration.
At the end it does not matter as you will WANT 2 axles to steer at a minimum!

GROUND CLEARANCE: Below axle clearance will be determined by tire size - Chassis clearance by axle spacing (break over angle)

To get the most for side-storage box space, I suggest to invest in a ultra long travel air suspension (or Kinetic).
Ultra long travel to move the "travel mode" height of the rig, not to have super high articulation...

Though possible, not necessary for the TL. What you DO want though is a way to raise and lower the truck according to the needs:

Smooth highway - HUG/scratch the road!! ...you can go as low as a Long Distance Coach (those that have to watch out for the ramp angle when deciding to go to a truck stop).....
and...
as high - so the lowest body sill is at the level of the upper 1/4 of a tire!

This most likely means that you will have some system underneath that moves the whole airbag up/down - .....probably Kinetic would be better adaptable for that ultra long travel thing....



LEVELING JACKS: I guess we all think hydraulics. HOWEVER, ELECTRICS are replacing hydraulics more and more.
Don't know about trucks, but in cars, most new design power-steering systems today are ELECTRIC-assist!

So - as we are already in the Electric Power Generating Business here - maybe the level jacks should be electric screw-jacks.
IF you use vertical and straight corner culumns to integrate the 4 hoist points - you could have SERIOUSLY long jack-screws inside these columns!
IF these columns are strong enough to hang the whole rig from them, they certainly should be able to support the structure on jacks from underneath...

[If there is no ELECTRIC power-steering assist available for this size rig - we are back with hydraulics - then I guess the lift roof is going up/down on electric jack-screws as well (?)....

You may be able to eliminate hydraulics completely.....



....I am SURE I am still missing some stuff you asked - ....later!

thjakits:snorkel:

 

[biotect]

And that is because???

Whether central motor and full axle or hub motors - the suspension system has NOTHING to do with it.
WHY do you think a hub motor HAS to have a IS?

Because it doesn't have a differential, doesn't have center-to-side axles or half-shafts and doesn't *need* a big tube from side to side to house the power delivery mechanics.

Yes, you *can* stick a big tube in there between the hubs, but if you have a drive at each hub, you don't need it. If you put it there, it's not because you need it, it's because you *want* it for some other reason.

Which is why just about every drive hub setup I see on the net has IS.

Hi dwh,

Sorry that my string of posts about breakover angles and such sort of "wrapped around" your most recent short posts.

With respect to this exchange: here I think the issue is really the one raised by Haf-E: dirt, water, sand, mud. Hub-drive electric motors will be exactly where one probably does not want electric motors to be, in an overlanding vehicle. Hub-drive motors are fine for sports cars or race cars that drive on optimal pavement. But for an overlanding truck designed to drive on bad roads, having the electric motors quite distant from the wheels does seem like a good, sensible idea. For instance, on corrugated roads like the Tanami track, who knows whether any electric hub motor could withstand the constant pounding and vibration, if connected directly to the wheels. Whereas mounted up in the chassis, the suspension system would absorb most of the shocks, so the electric motors won't have to.

All best wishes,



Biotect

 

[thjakits]

This can be done separately from the discussion of suspension to a degree - but the hub motors will increase the unsprung weight significantly so that would need to be considered. Also the concern of how the hub motors will handle water crossings and sand as well as how they accommodate the brakes - including parking / emergency brakes.

Check back on one of my latest posts - about the Electric Racer - their 37KW motors are a bit bigger than a good fist and weigh around 3.4 kg.
Make them double the power and I bet they are still below 8 kg. NOTHING compared to the tire-wheel combo (~50kg+80kgs) - and most likely less than the drive-shaft in a SA.

IF a hub-motor like than can be sourced, put it in a sealed tube compartment at the end of the SA - which in this configuration would just be a hollow tube itself.....

Brakes: Just like they are mounted today on any and all cars/trucks!! I suppose we agree on all disks all around?!

(2) dwh: you are right about the Orangewerk vehicle. Just fancy brushguards. But I thought that the format of the pipework above the cab to lift away errant hanging powerlines seemed especially effective.

...comes to mind - the "Powerline-Lift-Brushguard" will mostly lift TREE branches!
The Terraliner will be a fairly tall rig - ...at least in some configurations....



This one shows in the EXTREME why I oppose IS for Terraliner!

I STILL need to see a IS on a vehicle the size/weight class of the Terraliner, that even equals the ground clearance of a SA, let alone betters it.....

I must be completely out of any understanding of present military requirements for AWD vehicles - I can't understand what advantage a IS as shown could have in ANY situation?? Next to no ground clearance - one wheel articulates up and leaves the center WAY down - a huge amount of links and joints = increased maintenance + increased failure points - at the size of this vehicle, you won't do much Rally Driving either.....

If there is anyone on the thread that has the insight on this, please let us know!! (Ex or present military that might know about the specifics...)

As you know, I've been worried for a while about the "breakover angle", inter-axle distance, and axle placement. .... But one salutary effect of researching commercial overlanding vehicles in depth, is realizing just how long their inter-axle distances tend to be, and how terrible their breakover angles must be as a consequence. .... It's rather surprising that they do not constantly turtle:

Remember, these guys are NOT real Overlanders and less so Explorers - their routes are scouted out to look "interesting", but mainly are so, that you don't even need 4x4. The idea is to give tourists a view of the wildlife and a guided tour that may feel/look like a Overlanding trip or Exploration trip, but actually are nothing more than a "rustical" bus tour.....


This guy looks like it doesn't even HAVE 4x4!!

...on this pic - I think I can spot the front axle - a typical NO drive - Straight Axle!

These are called a Truck Non-Drive Front Steer Axle (...or so says Mr. Google):

Actually, as you mentioned in a later post - properly designed portals might be very nice to have.

The portals aren't really about approach, departure and breakover angles - those can be improved simply with a higher suspension. The portals provide a higher clearance down the centerline of the vehicle. They also provide extra gearing right at the hub, which reduces the stress on axleshafts, differentials, driveshafts, etc.

But of course the also add complexity and unsprung weight.

Still, I think with one drive motor per axle, portals - at least for me - would be a serious consideration.

But I'd really have to spend some time trying to convince myself that they would be needed. Perhaps the extra gearing could be used to reduce the size of the drive motors. Certainly there would be a benefit in terms of centerline clearance.

But that might be perhaps offset by the loss of clearance on the sides where the portals are. If the drive motors actually fit within the wheels, then I probably would not add portals. But if the drive motors are outside of the wheel, then I might add portals.

You are absolutely right! In the Terraliner probably ANY e-motor will need some kind of reduction gearing to stay "small and fast".
A Portal hub offers the oportunity to take on part of the needed speed reduction.

There is no way to compare the loss of clearance at the hubs of a portal to a IS!! ANY IS I ever saw so far takes up a lot more "danger space" than any portal (...and mostly even any Straight SA...)

If you use a central e-motor and "mechanical" SA or Portal (....to call it something else than a old-style convential SA....), the minimum Portal offset will be dictated by the gear-ratio you want to employ.
If you use hub-motors your "electric" SA becomes basically a DeDion-Tube - make it any offset you like! (Be careful - no matter where the power/torque comes from, torque reactions still depend a LOT on the suspension pick-up point locations/geomentry!!)

If you look up DeDion images on google you will see mainly DeDion "flat portals" - with the tube offset from the hubs to the rear of the car instead of the top.....



A thought to axle location:

Thinking about the workings of a "equal axle spacing" outline on a truck with 10m+ - I have more and more the feeling that the available articulation won't be enough to make this work really well.
Then - if you go the pictured Zetros route - I REALLY,REALLY hate non-steered tandems! Just observe a tandem-drive dump-truck TRYING to go around a corner!!
First off all the tadem is getting all twisted out of shape, including tires and the front tires don't fair any better (part of the reason that many of those have fat/wide front tires - trying to get a better grip to force the rig around the corner! Concrete Trucks are another source to observe! ....besides, close quarters maneuvers need an incredible amount of power to FORCE all the tires over the ground!)

So - to avoid this you may have a self-steering tag-axle (...may be there are some out there, but I never saw a self-steering AND drive axle) or put in a full sterring axle.

If you already put in a full sterring axle, you can put it anywhere you want!

So - how about putting it more to the front?! You can space it out quite a bit from the front axle, but still way in front of the actual middle of the truck.
Both steering axles are closer together and the steering linkage doesn't have to extend all the way to the rear.

In earlier days one could see plenty of trucks with this configuration in Italy and the UK....
Nowadays - hardly ever....
...and of course - I am unable to locate any pic on the net of a "normal" truck with that configuration (OPTIMUUUUSP - HEEELP!)

Here are some REALLY old trucks:

Single Dually-rear drive axle , TWO non-drive steering axles in front......Mercedes of all!

MERCEDES LP 333 three-axle truck

....something old and English:

THINK of it as a 8-wheel MAN/KAT with the last axle axed (...cut off)....

Propperly configured you easily could make the non-steer rear axle the primary drive axle with a central e-motor and using a conventional, lockable SA - propably 90% of all driving!!
Make the front ones with hub-motors, saves a load of weight and use them mostly for recovery power-generation!

Furthermore the non-symetrical layout should help with designing the proper and predictable "behaviour" of Terraliner when going over the top of a ridge....

Need to think a little more about this....











thjakits

 

[dwh]

I agree with the direction you are going - it all sounds good - except - I think the question of 6 individual hub motors without differentials versus 3 separate motors with traditional straight axles with differentials is still open for discussion. This can be done separately from the discussion of suspension to a degree - but the hub motors will increase the unsprung weight significantly so that would need to be considered. Also the concern of how the hub motors will handle water crossings and sand as well as how they accommodate the brakes - including parking / emergency brakes.

I agree.

If the decision is made to go with a big tube across the center rather than IS, then I would start arguing in favor of 3 drive motors instead of six.

To begin; I'm a big fan of redundancy, but the six don't provide redundancy - all they really provide is 3 extra points of failure.

True, as thjakits has pointed out, you could house the drive motors inside the tube - but that is going to increase tube diameter. So rather than having a skinny tube with a big lump in the center, you're going to have a fat tube all the way across. Good luck servicing that setup on the side of the road.

Better I think to have one motor per axle, with the motors frame-mounted. Then the motors are relatively safe from damage (and vibration), and the axles will weigh less and result in lower unsprung weight.

Also, by doing it that way, you can use off-the-shelf axles (such as MAN, or even Mog) and existing suspension. And with a differential in the center, you can lock/unlock the differential as needed.



On another subject: While Haf-E mentioned brakes, he didn't mention *regenerative* braking, which is something that I think need to be considered as part of the whole "drive motors" question.

Also portals: If using off-the-shelf live axles, then portals are probably off the table unless they are Mog axles. I seem to recall reading somewhere that Marmon-Harrington makes portals for some of their axles, or perhaps used to, so there may be another option, but I have my doubts.

 

[dwh]

As you know, I am strongly inclining towards Haf-E’s proposed straight-axle solution. At this stage, I would need a lot of convincing to reconsider IS.

Well, I know it now. I didn't know it at the time or I wouldn't have kept presenting IS solutions.

 

[dwh]

.
This then makes me wonder:

(a) Do 4x4 commercial overlanding vehicles often turtle? Or are their breakover angles reasonably sufficient for the routes they run?

(b) If 4x4s do have a problem with turtling, then why do overlanding companies not use more 6x6’s? Oasis and Dragoman both seem to have some 6x6’s, but otherwise the 4x4 format seems far more common.

I doubt that it's a common problem.

That's a problem that you encounter off-road, but almost never on a road - even a bad road. When Stephen Stewart and Co. were doing road work in Tibet, they were breaking down the high center of the road to fill in the ruts so the other vehicles could make it through. The Mog had no problem. The ruts were created by bigger heavier (and almost certainly 2WD) trucks.

"When driving on roads like the N317 (as opposed to real off-road driving) the important thing is to have the same (or better) ground clearance as the most common vehicle (MCV) on the road (in this case the Dong Feng 7 Tonne truck). This is because any road hazard involving obstructions too big for the MCV will quickly get cleared by the MCV drivers."

http://www.xor.org.uk/travel/china2002/20021012.htm

Personally, I'd be more worried about A) sliding sideways off the trail or road, or B) getting stuck high-centered.

 

[thjakits]

Because it doesn't have a differential, doesn't have center-to-side axles or half-shafts and doesn't *need* a big tube from side to side to house the power delivery mechanics.

Yes, you *can* stick a big tube in there between the hubs, but if you have a drive at each hub, you don't need it. If you put it there, it's not because you need it, it's because you *want* it for some other reason.

Which is why just about every drive hub setup I see on the net has IS.

DWH,

I think you completely missunderstand WHY I prefer the SA.

It is NOT because I need it for power transfer from the diff to the axle - it is because of the way the suspension is located beneath the truck, how the suspension places/works the tires, how it applies/transfers torque/power to the ground - as a unit.

Obviously with hub-motors you don't need half-shafts. So - it actually is NOT a real SA anymore, but I still want the suspension-workings of a SA!!
....call it a DeDion without drive shafts....

You don't see any SA hub-motor set-ups yet, because nobody built a serial hybrid rock crawler yet!!

Most hub-motor stuff goes either into ultra-light-efficient-environmentally clean-urban transport -"solutions"
OR
into road racing applications WHERE IS is favored hands down!! ....and where you have next to no wheel travel!
[The TESLA is just a limo racer for the road - I understand it kicks seriously BUTT!]

Observe: MOST of these IS arrangements are about STRAIGHT out - hardly any angle - let's say wheel travel is a exaggerated 100mm (usually less on racers) - how much is the angle-CHANGE on the suspension - HOW much SIDEWAYS movement will that cause on the tire/wheel? (....very little)

With a IS on a Terraliner you would need a serious down-angle at least at the lower suspension arm = HUGE lateral displacement of the tire/wheel as soon as the suspension starts to cycle!

Again: Whatever power delivery system/solution you use - has NOTHING to do with the suspension configuration you chose!

E.g. road/track racers prefer IS, because you can adjust it for every single corner in infinite ways....

1/4 mile racers (usually) prefer a SA rear end, because it is less difficult to control on lauch than a IS (though depending on your base car, there are plenty of IS cars on 1/4 mile tracks). Dedicated 1/4 mile cars often have locked diffs - going straight, why bother with LS or open diffs!

Have a look at the Lotus 7 crowd (...and all the Se7en copies) - you get anything from SA, to DeDion to IS at the rear-end.

IS is for the seriously "educated" driver who knows how to "read" the car and how to handle it.

DeDion is generally the choice for the "general public" as it makes the rear end way more predictable - can't go as far to the edge as IS, but will break loose sonner and you can have all the fun drifting through hairpins and wasting your tires in the process....

You try to drift in a IS-Se7en, ....you better be on your toes fast!!

I bet - once electro packages for the Se7ens are available - the preferred rear end will STILL be a deDion Tube with the hub-motors put into the ends!!



thjakits

 

[dwh]

No thjakits, I *do* understand your argument. The "Live Axle vs. Independent" is an old and well worn campfire argument in the 4WD community ever since the 80's when manufacturers starting coming out with independent front suspension on 4x4 light duty trucks. Personally, I've usually taken the position that live axle is preferable. But that's when talking about four-wheeling for fun and profit.



My points are these:

IF you use one drive per wheel, then you don't need a big tube. I thought biotect was advocating one drive per wheel, so I approached my argument from that position. If you are going to use one per wheel, then IS is going to be the default.

IF you use IS AND one drive per wheel, then the argument that all that junk in the center makes it really no better than live axle is just plain wrong.

You posted a pic just above showing the military vehicle with all the junk in the center. Why did they do it that way? I don't know...and it doesn't matter...

Because it doesn't *have* to be done that way. That just one way to do it. There are heavy-duty suspension systems on the road right now, that can be easily converted to IS and *don't* have all that junk in the center.

So the "junk in the center" argument just doesn't stand up. I CAN see many good reasons for going with a live axle instead of independent - but "junk in the center" is NOT one of them.



Having said that, if biotect has made a decision for live axle, then I'm going to oppose the one drive per wheel idea (which I'm pretty sure wasn't my idea and I didn't advocate anyway) in favor of one drive motor per axle.

 

[thjakits]

A few encounters from the net - all mentioned at some point on this thread:


ART DECO ???

Looking for Trucks with a single rear drive axle and dual front steering axles, I stumbled on this one:


The BIG ROTEL RIG!!

And one from "our good friend" Colani!!

I especially like this:

Luigi Colani is a Swiss-German industrial designer who happened to design this fantastic truck. Rather than calling himself a designer he calls himself a "three-dimensional philosopher of the future" and believes that fluidity of shape and form, and smooth, ergonomic appearances are the true way forward with design.

Jesus, BIO - ARE YOU SURE Colani is not your long lost uncle or somethin' ? :elkgrin::elkgrin::elkgrin:



Not even THESE guys use a IS - keep it simple and predictable!! This is a custom-made rig - if they wanted they could have done a IS - no doubt.....






'nough fun!

Back to thinking about axle layouts!

thjakits

 

[thjakits]

What interests me in all of this is the comparative geometry. Many of these 6x6s are very long, too; the Unicats pictured, for instance, are well over 10 m. But somehow that extra axle makes all the difference in the world, and all of these 6x6s seem much less likely to “turtle”, than the 4x4 commercial overlanding vehicles shown at the very beginning. To compare visually, just open the previous page in a new window, at http://www.expeditionportal.com/foru...-Frame/page107 . The difference between the commercial overlanding 4x4 trucks, and these 6x6s, is really quite striking.

Honestly? I doubt that most of these have a 6x6 for break-over-angle reasons - they are just too heavy for a 2-axle lay-out!!

The Tour Rigs ("Commercial Overlanders") - don't have to carry all the paraphernalia a Explorer/REAL Overlander needs/takes along, ...so they get away with their 2 axles.....

But, as I was pointing out - those long links don't necessarily have to be side-to-side, they can be fore-and-aft. So you could have the IS, and the extra travel, without the stuff cluttering up the center underneath the vehicle.

No matter which suspension you chose - IF you want some serious articulation and/or "drive mode" adjustability you WILL have some seriously long links to locate your IS or AS or "whatever"-S .......just comes with the territory.

With respect to this exchange: here I think the issue is really the one raised by Haf-E: dirt, water, sand, mud. Hub-drive electric motors will be exactly where one probably does not want electric motors to be, in an overlanding vehicle. Hub-drive motors are fine for sports cars or race cars that drive on optimal pavement. But for an overlanding truck designed to drive on bad roads, having the electric motors quite distant from the wheels does seem like a good, sensible idea. For instance, on corrugated roads like the Tanami track, who knows whether any electric hub motor could withstand the constant pounding and vibration, if connected directly to the wheels. Whereas mounted up in the chassis, the suspension system would absorb most of the shocks, so the electric motors won't have to.

I think this would NOT be an issue at all!! No matter in WHAT vehicle you mount hub-motors, they better be waterproof anyway!!
...unless you restrict your driving to sunshine weather only and hopefully never encounter a ditch!!

Hubmotors on a IS sportscar in the rain will not only get wet - they will get wet in a HURRICANE!!

Conventional driven hubs - SA or IS also have to be completely sealed or they would contaminate the grease/oil in the hubs/axles - no good either....

In a SA layout or a IS layout you can provide a sealed tub in which to mount the e-motor, just need to provide the proper cooling - big enough conducting surfaces....

True, as thjakits has pointed out, you could house the drive motors inside the tube - but that is going to increase tube diameter. So rather than having a skinny tube with a big lump in the center, you're going to have a fat tube all the way across. Good luck servicing that setup on the side of the road.

Just to clear this up - when I think of this layout I also think of small-diameter, longish, geared e-motors (like the ones on the Grimsel racer) - this layout WON'T work for big diameter-pancake-"In Wheel"-hub motors.......
IF the long/narrow motors cna be sourced, the a straight axle tube should be no more than about 6"/160mm in diameter.
However, I would just make the axle-tube any diameter conveniant - even square or rectangular if that fits the bill and just get the ends wider and formed according to the needs of the e-motor. If we talk about huge pancake motors, they "disappear" inside the wheel anyway - AND I am NOT a fan of these anyway, BECAUSE of their weight!!

Better I think to have one motor per axle, with the motors frame-mounted. Then the motors are relatively safe from damage (and vibration), and the axles will weigh less and result in lower unsprung weight.
...
Also, by doing it that way, you can use off-the-shelf axles (such as MAN, or even Mog) and existing suspension. And with a differential in the center, you can lock/unlock the differential as needed.
...
On another subject: While Haf-E mentioned brakes, he didn't mention *regenerative* braking, which is something that I think need to be considered as part of the whole "drive motors" question.
...
Also portals: If using off-the-shelf live axles, then portals are probably off the table unless they are Mog axles. I seem to recall reading somewhere that Marmon-Harrington makes portals for some of their axles, or perhaps used to, so there may be another option, but I have my doubts.

I do favor this approach too, but it might be more efficient and lighter (...or less heavy) to go with a big e-motor and a conventional SA on the "Main Drive Axle" and Hub-motors in the other two axles - however, when I picture this I always have the small diameter, longish e-motors in mind.....

"Off-the-shelf" for axles for a project of this magnitude doesn't really depend on specific vehicle spec axles.
Any axle manufacturer will be able to customize your axles with standard housings, gear-ratios, axle width, hub configurations, etc...
Maybe the latest BIG MOG axles could survive.....

Regenerative braking is on the MUST DO list since the very start of this project. A hybrid WITHOUT re-gen-braking would be the biggest joke in the industry!!
Considering a truck like Terraliner makes sense as a hybrid basically ONLY BECAUSE of regen-braking! The storable amount of energy in the batteries wouldn't get you very far.....

Have a look a load of posts back, when Campo (...I think?) showed info from the latest Truck Expo - the new BOSCH-parallel-hybrid system for Fullsize Trucks:

Battery only range ~ 6km (enough for short Inner City trips and to maneuver on loading ramps) the rest of the game is efficiency by re-gen-braking!! You couldn't get enough batteries into a big rig to make it through a normal day's journey anyway - ...or if you get close to a day you have no weight for actual freight left!!

Check this:



Going all over board you might even build a REAL DeDion axle!! Connect the wheels/hubs with the DeDion Tube and drive the hubs with IS-half-shafts!! STILL a better ground clearance than IS and STILL the suspension action of a SA!.....but if I could avoid the half-shafts out in the open, I would!

Quote Originally Posted by biotect View Post
As you know, I am strongly inclining towards Haf-E's proposed straight-axle solution. At this stage, I would need a lot of convincing to reconsider IS.

Quote Originally Posted by dwh
Well, I know it now. I didn't know it at the time or I wouldn't have kept presenting IS solutions.

dwh - why DON'T you keep presenting IS solutions?!! Bring it on - we might all be wrong after all! I just would like to get a crack at each and every trial to refute the SA for THIS project - if I run out of objections, you have found THE IS that convinces me (...and most likely Bio and others), that that particular IS approach is indeed better than a SA!

Bio changed his mind a load of times during this discussion - he was already settled on IS, but he was convinced otherwise (...by hopefully solid arguments) - what makes you think you could not change his mind again (....with hopefully solid arguments!)

Bio was deadfast set on equal-spaced axle placing - .....if I am not mistaken, this might be seriously in question by now!
Actually - the longer I think about it, the more I am against it - for trucks the length of Terraliner - ....just need to think about it some more....I already suggested a possible alternative layout and some reasoning behind it - .....just need to think about it some more -

thjakits

 

[thjakits]

No thjakits, I *do* understand your argument. The "Live Axle vs. Independent" is an old and well worn campfire argument in the 4WD community ever since the 80's when manufacturers starting coming out with independent front suspension on 4x4 light duty trucks. Personally, I've usually taken the position that live axle is preferable. But that's when talking about four-wheeling for fun and profit.



My points are these:

IF you use one drive per wheel, then you don't need a big tube. I thought biotect was advocating one drive per wheel, so I approached my argument from that position. If you are going to use one per wheel, then IS is going to be the default.

IF you use IS AND one drive per wheel, then the argument that all that junk in the center makes it really no better than live axle is just plain wrong.

You posted a pic just above showing the military vehicle with all the junk in the center. Why did they do it that way? I don't know...and it doesn't matter...

Because it doesn't *have* to be done that way. That just one way to do it. There are heavy-duty suspension systems on the road right now, that can be easily converted to IS and *don't* have all that junk in the center.

So the "junk in the center" argument just doesn't stand up. I CAN see many good reasons for going with a live axle instead of independent - but "junk in the center" is NOT one of them.



Having said that, if biotect has made a decision for live axle, then I'm going to oppose the one drive per wheel idea (which I'm pretty sure wasn't my idea and I didn't advocate anyway) in favor of one drive motor per axle.

Great!!

IF you have any TRUCK size IS info (text/pics/video) please let us know!!

In my mind I just can't picture a IS with enough ground clearance and NO "lateral tire movement" problem.....

[I really would like to find something like that...]

I was dead set against all hub-motors a while ago - ...I believe there is quite a bit of pro/contra arguments left to discuss (....however for my part restricted to the small diameter, long, light weight motors - .....just can't get my head around to the heavy "In Wheel" pancakes....)

Just for the sake of it - as I mentioned it somewhere - here the 1st post of a possibly very interesting thread:

Motor help needed for hybrid rock crawler...
My brother and I are looking into the possibility of custom building a hybrid rock crawler. We have plenty of experience mechanically to fabricate just about anything, but neither of us has any experience when it comes to dealing with electric powered vehicles.

We decided to go electric because the power curve of an electric vehicle makes it ideal for "rock crawling." As the motors are able to deliver full torque from basically 0 rpm.

The area we need help in is what motor and battery configuration is needed to accomplish the build and have it drive as intended. The finished vehicle weight is estimated to be around 800 pounds or so, not including the motor and batteries. It will spend about 80% of it's life traveling at under 10mph, however it should be able to acheive at least 25mph...40+ would be ideal. We would like to keep voltage down around 48 volts, but 96 isnt out of the question. Mostly because we dont want to carry more than 4 cells...8 max to keep weight down. We realize this will limit range signifigantly,so we plan on running an onboard generator to help keep the batteries charged. Since the vehicle will spend most of its time at very low speeds without much of any load on the motor, we were thinking 6500 watts (120v A/C) or so should do it, or is that too much / little? Hooked up so that it starts and stops itself as needed to keep the batteries fully charged. Further, in any given day on the trail the distance traveled is usually between 10 and 30 miles...sometimes more or less. In cases of fewer miles, it typically means we are driving over much larger rocks and difficult terrain at very low speeds requiring lots of low end tourque, and the opposite is true as distance traveled increases.

We would like to couple the motor directly to a transfer case without a transmission at all. We plan on using a gear driven toyota transfer case. We belive that between the available gearing of the T-case a transmission shouldnt be needed as there are alot of options for gear ratios without a tranny. One or two cases stacked together are available options for the build. Each case has a standard high range ratio of 1:1 and 2.28 low range, and one or both cases can easily be re-geared to produce a low range of 4.7:1. The cases are able to be shifted on the fly independant of each other as well. So bewteen the T-case(s) and available axle ratios ranging from about 3.5 - 5.7:1, making the final drive ratio a range from 3.5 to over 120:1. Will this be enough to turn a 33" - 35" tire? Bear in mind that this vehicle will need to propel itself up near vertical inclines at times at speeds as low as possible. (<1mph) Allbeit, these climbs are less than 30 feet long each at max, typically only 5-10.

Also, being that this is going to be a strict off-road only vehicle, it's motor will need to be able to survive continuous operation in very dusty conditons at best. Are there any motors available that are sealed? Occasionally the motor may be submerged if a deep water crossing is needed, although this will be avoided whenever possible. The vehicle will need to be washed though, and the motor will certainly get wet at least doing that.

Essentially, we need help figuring out what size / type of motor would be best for this given its weight and what of the available gearing would be needed given the large tire size. Any help and or ideas would be great.

Thanks.

HURRAY! - sounds like the "Little Explorer" we should trailer along with the Terraliner!! Let's mount a roof tent on it, so we can camp out for a day or 2 away from the Terraliner Base Camp!! :sombrero:



...the rest of the (rather short) story is here:

http://www.diyelectriccar.com/forums/showthread.php/motor-help-needed-hybrid-rock-crawler-50729.html


cheers,

thjakits

 

[thjakits]

FINALLY!!

I found a Rally Truck with IS:

...and the "Dutch One" again with SA (I think...)

....some more "Reflection Material":

SPARES:

"SUPPORT PROGRAM":

more fun:

For the rest of this fun:
http://www.captainsvoyage-forum.com/forum/club-international-things-from-around-the-world/road-kill-transportation-roadside-cars-buses-trucks-trains/945-sporttrucks


SA-leaf springs:

INTEGRATED KAT:

IS:

WIDE-SPACED Tandem:

NARROW SPACED Tandem:

ZETROS Explorer Garage:

thjakits












thjakits

 

[thjakits]

PROPOSED AXLE CONFIGURATION:



Dual front steering - single rear drive:

SOME of the problems on a TATRA:

TATRA axle / driveshaft arrangement:

Centre tube chassis with all drivetrain enclosed... double crownwheel and half axle set up means 30mm difference in wheel alignment each side.

thjakits

 

[optimusprime]

Bucking for promotion. Watch your back there biotect, he's got his eye on your job.

Nope nope nope and nope!

 

[optimusprime]

Honestly, if it's anything at all like my last job, he can have it!! My last job had me progressively bumped up to the managerial level, with much less time to engage in the "Art" or "Design" end of things. Responsible for 20 people, and everything they did wrong; would arrive in the morning and find 80 new emails in my in-box. I was a good manager, and they paid me handsomely for it. Every time I began talking about leaving, they'd offer me a raise. But it was a golden cage.

So I did the deliberately contrarian thing: made a conscious decision to leave security and status, and return to my true calling, as an artist and a designer....

The job of designer optimusprime can certainly have, too; the world needs more ethically committed designers, and optimus strikes me as a stand-up kind of guy. There is room for all of us here on Earth, and certainly in this thread. And beyond that, there is no question that the TerraLiner design has "shifted" in countless ways, large and small, because of the input of everyone who has contributed to the thread. In that sense, it really has become a team effort.

All best wishes,



Biotect

Its a good job we dont know each other in real life!!
Been in management roles myself, all right to start with,but in the end i hated it with a passion, so i'll stick with being told what to do now if you don't mind! My CV is definately off the table!