TerraLiner:12 m Globally Mobile Beach House/Class-A Crossover w 6x6 Hybrid Drivetrain
- Thread starter biotect
- Start date
Hi all!
Have a look at this:
http://www.gizmag.com/electric-car-...ail&utm_term=0_65b67362bd-145982622c-90808789
Especially at the size and form of the hub motor in the video clip!
It is mentioned in the text, that these are NOT the strongest motors on the market, yet
!!
Pending investifation and search by BIO - he still may be able to EFFICIENTLY use hub motors!
[...the last ones I was aware off were heavy, narrow big diameter units. The shown, different design version looks great!]
Cheers all,
thjakits
Have a look at this:
http://www.gizmag.com/electric-car-...ail&utm_term=0_65b67362bd-145982622c-90808789
Especially at the size and form of the hub motor in the video clip!
It is mentioned in the text, that these are NOT the strongest motors on the market, yet
!!
Pending investifation and search by BIO - he still may be able to EFFICIENTLY use hub motors!
[...the last ones I was aware off were heavy, narrow big diameter units. The shown, different design version looks great!]
Cheers all,
thjakits
free radical
New member
Interesting tread and subject and something that's been on my mind for sometime also,,an RV capable to travel anywhere in any weather in
comfort..
The only truck I'd consider building on would be Czech Tatra with its solid tube backbone frame which has absolutely no flex,
so building a cargo box or living quarters of any type would be fairly easy to do
Plus those independent suspension axles make it one, if not "the"most capable off road machine..
Tatra
http://youtu.be/0GGrHhywzsA
http://youtu.be/la8jxk5rr_Q
Tatra Dakar
http://youtu.be/7JYIEY5iF_E
I will add more ideas on my design later,time permitting ...
comfort..
The only truck I'd consider building on would be Czech Tatra with its solid tube backbone frame which has absolutely no flex,
so building a cargo box or living quarters of any type would be fairly easy to do
Plus those independent suspension axles make it one, if not "the"most capable off road machine..
Tatra
http://youtu.be/0GGrHhywzsA
http://youtu.be/la8jxk5rr_Q
Tatra Dakar
http://youtu.be/7JYIEY5iF_E
I will add more ideas on my design later,time permitting ...
Czechsix
Watching you from a ridge
Yah, but OH that weight.....which is why I stayed away from them for camper purposes.
biotect
Designer
Hi all,
Just wanted to say "hello". I've been following the thread, but resisting the temptation to contribute, because my academic commitments are now so onerous. But great dialogue developing here!! Will contribute more substantively near the middle of December, when the academic work-load is no longer 24/7.
All best wishes,
Biotect
Just wanted to say "hello". I've been following the thread, but resisting the temptation to contribute, because my academic commitments are now so onerous. But great dialogue developing here!! Will contribute more substantively near the middle of December, when the academic work-load is no longer 24/7.
All best wishes,
Biotect
nick disjunkt
Adventurer
Hi biotect, I'm not sure how seriously you want to progress with e-drive but I met a guy recently working for GKN who is working on the development of large electric motors. GKN have a long history of building gearboxes and axles for british military trucks and so they no doubt understand the implications of off road use.
GKN build the axles in these (now superceded) Foden 8x6 trucks
GKN build the axles in these (now superceded) Foden 8x6 trucks
nick disjunkt
Adventurer
Thanks campo,
I'm back at work in London now, starting the process of saving again for another trip. Some people can earn money whilst travelling but for me this hasn't been possible yet.
For the type of travelling that I enjoy, it is more important that I have a rugged vehicle with good ground clearance, than one with exceptional off-roading capacity. On the trip that I have just finished there was never an occasion where I needed 4x4. . The only times where we were not able to continue on the path that we wanted were a result of gearing or size, never traction. On the few occasions where we became bogged, I engaged the rear differential lock and rocked/dug/slid myself out.
This was more a function of the times of year that we were travelling, than the ability of our 4x2. Most gravel roads are passable in 4x2 in any conditions, and these can get you far out into the wilderness in most of the areas that we visited, but on several occasions we drove down dirt roads with no sub-base, just graded (or sometimes ungraded) dirt. These kinds of roads are fine in dry conditions, but when it rains too often for the road to dry out we would have had major difficulties. It was May, and thus the rainy season, when we returned to Chiapas from the Yucatan, and if we had continued south I suspect we might have wished we had 4x4. The videos on the YouTube of mud roads in Russia and Africa are testament to how bad these type of road can get.
For me, the major benefit that I would have gained from using the 4x4 Atego, rather than the 4x2 version, would have been the 2:1 ration in the transfer box. At the kind of crawling speed I needed to do when driving on extremely rocky tracks, I cannot give the engine sufficient revs to generate much power; this is acceptable on flat ground but in the mountains it is impossible to continue. The only solution in some cases was to drive much faster than is comfortable on such roads (12km/h). If I see a wrecked 4x4 1823 in the future I may try to do a deal on the transfer box.
Safe travels,
Nick
biotect
Designer
.
*********************************************
.AXLES AND SUSPENSION SYSTEMS: OSHKOSH TAK-4
*********************************************
Hi all,
Again, wanted to repeat that a great dialogue seems to be developing here about axles and suspensions. I am still loaded up with academic work, but wanted to make just one small contribution, in response to some of the comments directly above.
As usual, I am inclined to agree with egn, that the simpler and more "proven" the axle and suspension system, the better. This is one area where I would be inclined to remain very conservative in the TerraLiner, going with "fully proven" technology, as opposed to "futuristic" technology:
That's also why I remain attached to the idea of a Tatra backbone tube serving as the "base", around which a tubular space-frame might be constructed, as per a Prevost or MAN touring coach. I've been trying to contact Tatra to get an estimate of what the tube + swing axles would weigh, on their own, without anything else added, for a 6x6. So I very much agree with free radical, but I also agree with Czechsix, regarding the worry about weight:
freeradical: it would be great to see your design ideas for a Tatra-based 6x6 camper. Did you read some of the earlier material where i discussed "semi-monocoque" and "true monocoque" construction with Campo? I've been thinking that the Tatra "tube" could be surrounded by a "half-height" tubular space frame, up to 1.6 m; and that above that, the camper body itself would be true monocoque, with only titanium roll bars embedded. See pages 73 and 74 in this thread, posts #722 to #736 in this thread, at http://www.expeditionportal.com/for...pedition-RV-w-Rigid-Torsion-Free-Frame/page73 and http://www.expeditionportal.com/for...pedition-RV-w-Rigid-Torsion-Free-Frame/page74 . It would be good to get your reaction to those posts, and the discussion that followed those posts.....
*********************************************
Now here is the contribution: there does exist a completely "proven" independent suspension technology other than Tatra, for heavy-duty off-road travel in a large vehicle: the TAK-4 suspension system made by Oshkosh. Oshkosh describes its TAK 4 suspension as follows:
See https://oshkoshdefense.com/technology-1/advanced-suspension-technology/ , http://oshkoshdefense.com/components/tak-4/ , http://oshkoshdefense.com/wp-content/uploads/2014/09/OshDef_TAK4_FamBrch_SnglPgs_LowRes.pdf , http://www.army-guide.com/eng/product3871.html , http://oshkoshdefense.com/wp-content/uploads/2013/08/HMMWV_TAK4_SS_6-13-11.pdf , http://oshkoshdefense.com/wp-content/uploads/2013/08/Technology_Bro_12-13-2010.pdf , http://www.oshkoshdefense.co.uk/wp-content/uploads/2014/01/EN-UK_Technology_Bro_6-3-2011.pdf , http://www.hybrid-vehicle.org/hybrid-truck-hemtt.html , https://oshkoshdefense.com/vehicles/hemtt-a3-diesel-electric/ , and http://oshkoshdefense.com/wp-content/uploads/2013/08/HEMTT_A3_SS_6-13-11.pdf :
[video=youtube;4bXpy2zMzmw]https://www.youtube.com/watch?v=4bXpy2zMzmw [/video] [video=youtube;-PAAJ82FfFI]https://www.youtube.com/watch?v=-PAAJ82FfFI [/video]
Oshkosh uses the TAK-4 system across its entire product range, from the smallest 4x4s to the largest 10x10 trucks.
Oshkosh also uses the TAK-4 suspension system in its "Striker" ARFF (Aircraft Rescue and Fire Fighting) vehicles, and its "Pierce" line of firetrucks -- see http://www.dieselpowermag.com/featu...r_oshkosh_striker/photo_07.html#__federated=1 , http://www.oshkoshairport.com/Oshko...PDF Documents/ARFF Trucks/Striker3000_6x6.PDF , http://w ww.team-eagle.ca/wp-content/uploads/2011/06/Oshkosh_Striker3000.pdf, http://piercemfg.com/en/experience/the-difference/product-technology/tak-4.aspx , http://www.piercemfg.com/PierceMfg/...nloads/Literature/PDFs/TAK-4-IFS-Brochure.pdf , http://www.piercemfg.com/PierceMfg/...e/Product Technology/TAK-4/TAK4_final-(1).pdf , and http://piercemfg.com/PierceMfg/medi...echnology/TAK-4/Pierce_TAK-4_Lipski_story.pdf .
So if anyone reading this knows something about the Oshkosh TAK-4 suspension system, and its possible application to the design of a "bad-road" TerraLiner, please chime in! Like the Tatra swing-axle system, the TAK-4 system provides tremendous wheel-travel, but it's not "backbone tube" technology.
All best wishes,
Biotect
*********************************************
.AXLES AND SUSPENSION SYSTEMS: OSHKOSH TAK-4
*********************************************
Hi all,
Again, wanted to repeat that a great dialogue seems to be developing here about axles and suspensions. I am still loaded up with academic work, but wanted to make just one small contribution, in response to some of the comments directly above.
As usual, I am inclined to agree with egn, that the simpler and more "proven" the axle and suspension system, the better. This is one area where I would be inclined to remain very conservative in the TerraLiner, going with "fully proven" technology, as opposed to "futuristic" technology:
That's also why I remain attached to the idea of a Tatra backbone tube serving as the "base", around which a tubular space-frame might be constructed, as per a Prevost or MAN touring coach. I've been trying to contact Tatra to get an estimate of what the tube + swing axles would weigh, on their own, without anything else added, for a 6x6. So I very much agree with free radical, but I also agree with Czechsix, regarding the worry about weight:
freeradical: it would be great to see your design ideas for a Tatra-based 6x6 camper. Did you read some of the earlier material where i discussed "semi-monocoque" and "true monocoque" construction with Campo? I've been thinking that the Tatra "tube" could be surrounded by a "half-height" tubular space frame, up to 1.6 m; and that above that, the camper body itself would be true monocoque, with only titanium roll bars embedded. See pages 73 and 74 in this thread, posts #722 to #736 in this thread, at http://www.expeditionportal.com/for...pedition-RV-w-Rigid-Torsion-Free-Frame/page73 and http://www.expeditionportal.com/for...pedition-RV-w-Rigid-Torsion-Free-Frame/page74 . It would be good to get your reaction to those posts, and the discussion that followed those posts.....
*********************************************
Now here is the contribution: there does exist a completely "proven" independent suspension technology other than Tatra, for heavy-duty off-road travel in a large vehicle: the TAK-4 suspension system made by Oshkosh. Oshkosh describes its TAK 4 suspension as follows:
See https://oshkoshdefense.com/technology-1/advanced-suspension-technology/ , http://oshkoshdefense.com/components/tak-4/ , http://oshkoshdefense.com/wp-content/uploads/2014/09/OshDef_TAK4_FamBrch_SnglPgs_LowRes.pdf , http://www.army-guide.com/eng/product3871.html , http://oshkoshdefense.com/wp-content/uploads/2013/08/HMMWV_TAK4_SS_6-13-11.pdf , http://oshkoshdefense.com/wp-content/uploads/2013/08/Technology_Bro_12-13-2010.pdf , http://www.oshkoshdefense.co.uk/wp-content/uploads/2014/01/EN-UK_Technology_Bro_6-3-2011.pdf , http://www.hybrid-vehicle.org/hybrid-truck-hemtt.html , https://oshkoshdefense.com/vehicles/hemtt-a3-diesel-electric/ , and http://oshkoshdefense.com/wp-content/uploads/2013/08/HEMTT_A3_SS_6-13-11.pdf :
[video=youtube;4bXpy2zMzmw]https://www.youtube.com/watch?v=4bXpy2zMzmw [/video] [video=youtube;-PAAJ82FfFI]https://www.youtube.com/watch?v=-PAAJ82FfFI [/video]
Oshkosh uses the TAK-4 system across its entire product range, from the smallest 4x4s to the largest 10x10 trucks.
Oshkosh also uses the TAK-4 suspension system in its "Striker" ARFF (Aircraft Rescue and Fire Fighting) vehicles, and its "Pierce" line of firetrucks -- see http://www.dieselpowermag.com/featu...r_oshkosh_striker/photo_07.html#__federated=1 , http://www.oshkoshairport.com/Oshko...PDF Documents/ARFF Trucks/Striker3000_6x6.PDF , http://w ww.team-eagle.ca/wp-content/uploads/2011/06/Oshkosh_Striker3000.pdf, http://piercemfg.com/en/experience/the-difference/product-technology/tak-4.aspx , http://www.piercemfg.com/PierceMfg/...nloads/Literature/PDFs/TAK-4-IFS-Brochure.pdf , http://www.piercemfg.com/PierceMfg/...e/Product Technology/TAK-4/TAK4_final-(1).pdf , and http://piercemfg.com/PierceMfg/medi...echnology/TAK-4/Pierce_TAK-4_Lipski_story.pdf .
So if anyone reading this knows something about the Oshkosh TAK-4 suspension system, and its possible application to the design of a "bad-road" TerraLiner, please chime in! Like the Tatra swing-axle system, the TAK-4 system provides tremendous wheel-travel, but it's not "backbone tube" technology.
All best wishes,
Biotect
Last edited:
free radical
New member
Me thinks titanium roll bars maybe bit of an unnecessary overkill as regular steel tubing will do the job just fine and for way less $$...something like many off roaders use,,one in front and another in rear of vehicle surounding the structure should suffice imo
http://youtu.be/GRwkZ7MCepI
Since Tatra chasis has no flex building any structure on it should be fairly simple.
One could even bolt one of those metal transport containers on it cut windows and doors in it and insulate it for comfort,after all there are people who make house from those things nowadays
Sure would make for one strong shelter in case one gets attacked by some wild dinosaurs.
There're some vids of military Tatras so Ill check just what type of structures they use..
I'd probably go with simple Insulated Structural Panels as these are readily available with plywood on both sides rigid insulation in the middle and in thicknesses from 2 to 6 inches which should be plenty to keep one comfortable in any weather..
And these can be had in any length up to forty feet I think,so making a building would be quite easy and quick..and when properly glued and bolted together these type of buildings are strong enough to survive an earthquake of highest magnitude without damage,there were tests done by shaking these and the machine broke before the house.
Should be just fine for an RV no doubt..
And as the smallest Tatra 4x4 can carry about 10 ton if I recall correctly it should have no problems carrying that weight..
That's the only thing I don't like about Tatra trucks,they are way too big huge and heavy for my needs..one ton would be plenty for me..
Sure wish Tatra was making smaller 1 ton or 2 ton trucks!
Have to sign off now,will be back later..
Hi all,
well, all nice banter here - nice ideas and all, but at SOME POINT you will have to settle on a path through the proposed project (..you already have a list and along this discussion you eliminated quite a few of your initial ideas, mainly when it comes to "proven", "simple", and weight issues...)
Though the TATRA system is NICE!! - it is NOT simple. Very capable, but IF you have trouble with it on the road (...we agreed to stay ON roads, right?), you are on your own - ....and the hopefully excellent long distance support from TATRA!
Unless you "have the need for speed!" - (which you will NOT have in a camper...) - the Independent suspension (latest Oshkosh or any other) will be overkill and more complex than you want.
Military needs/wants to go as fast as possible when on the move - make this more a "Rally"-like environment, the places you want to go with the Terraliner will want better ground clearance - like in SOLID AXLES.
A Solid Axle suspension with airbags will be able to be serviced about anywhere in the world and you won't notice any difference in ride comfort to any other suspension.....[ many proven 4x4s have/had solid axles at least until recently, Toyota Land Cruiser, Nissan Patrol, Land Rover, Mercedes-G, etc.... - why go for something complex if you don't need it??? - higger the vehicle the less harsh/bouncy a solid axle becomes - Just count the "moving links of a Solid Axle System versus a Independent System... All these links are usually bearings or rubber bushes or Poly-bushes - ALL of these eventually wear out and need replacing - make it as easy as possible!!]
Rollbars - if you already make a NEW Terraliner, might as well built these in - Carbon/kevlar monocoque box or steel space frame - "rollbars" INCLUDED INTO the structure. Just put a few "wear"-pieces on the outside!
Looking good and all martial - exo-cages/rollbars are DEFINITELY an aerodynamic no-no!! ON the long highway runs they will not help with economy.
I like the "Tatra Chassis with a Container"-idea, except - "integrating", as a top priority of Bio - ...would be seriously tough!
Also a 40/45 footer will weight in at better than 4 tons - ...then, you would have your rollbars included and have an excellent basis for slide-out construction all around! However you would have to build a complete new front end (cab) to somehow "integrate"....
Then - depending on price, a conventional chassis (like Campo's ride) might just be fine as well - if you mount the container solid! ....and you get "maintainability around the world" back!
ON the other hand you will always lose 4-tons of the overall weight just to the box! If that would be a good way to do it for a commercial product, all the established expedition vehicle builders would have done it long time ago (I am sure at some point they all did look at that possibility...]
Now - if your travel plans include politically less hospital areas - with a container as your walls - you are also save from lead laden air - you will need a .50 cal. or an RPG to get through the container!
If SERIAL-HYBRID is still a must in the requirements department - you might also forget about the TATRA chassis - there is TONS of gears in that system, eating up TONS of power along the way - The Tatra chassis is one big transmission that was stretched into a chassis!!
If your drive units are going to be electric you want to eliminate as many transmission-gears as possible to avoid transmission losses!
By the time you modified the TATRA chassis to that extend, there is not much left of it!
Then you might as well just build your own tube chassis with pendular axles and hub motors - back to the discussion about electric motors and efficiency!
Again - I think your best bet is to NOT push innovation for innovations sake!
Sometimes INNOVATION is mostly simplification and going back to basics!!
[As an excellent sample have a read-up on this: http://www.autospeed.com/cms/article.html?&A=111091 ...the gentleman discusses the merits of different suspension layouts for this particular application. To get to the optimum solution for a PARTICULAR case - you can't just copy/paste from others!]
Also - compare youtube stuff from the HUMMER/HUMVEE in the muck/off-road to others of similar size and purpose (Unimog, Volvo C303 to C306, Pinzgauer, etc....), and you will see that Independent Suspensions (Oshkosh style - Tatra/Pinzgauer pedular axles are different......) in these situations are quite limited!
And mostly not by traction - you can get that by proper tire choice and loads of lockers (...see Tatra and Pinzgauer - will have a wheel in the air quite often!) . It is the chassis that mainly gets in the way!
Nice articulation at every wheel with the independent suspension, but it does not lift the bottom of the car out of the way of obstacles!!
Just to throw it into the discussion: You should think about not taking it too seriously with the "Rigid Frame" requirement.
As a fact, there is no such thing! EVERYTHING flexes! Tatra and MAN/KAT are just closer to the rigid edge, Unimog (e.g.) closer to the flexible edge (...on purpose!).
Have also a look into aviation - airliners would NOT be possible if designed with as a much rigidity as possible - they would break up shortly!
[Ever observed a wing on take-off? Tips are WAY up long before the liner gets off the wheels! Also look at the wings in flight: Quite scary to see them bounce around!! No worries - they are DESIGNED for that!]
Very simply said: The stiffer something is the worse the failure mode: compare a metal can of fruit (bend the top or the can as you wish - you will get tired before it BREAKS!) - now, do the same to a piece of glass!! You can't bend it even 5% of the amount you bent the can! ....and the failure mode is - "catastrophic"! Of course these are the extreme samples, but the idea holds throughout every engineering application!
A big rig WILL flex! ....OR it WILL be HEAVY for rigidity .....OR complex (make that EXPENSIVE) to triangulate/sandwich/honeycomb the system....
The bigger units become the EXPONENTIALLY bigger/bigger become the rigidity deficits.....
So - you might want to think about building smaller "rigid" modules and connect them with a specific amount of flex allowed.
Chassis-Living area interface!
Hey Free Radical: ...check out this vid: https://www.youtube.com/watch?v=GAU3349luk0
...you won't find a single Tatra - I bet it is because of the ridiculous front overhang these rigs have. The newer machines are loads better, but your sample video doesn't TATRA any good regarding off-road-ability!
And knowing how capable these off-roaders are building their rigs, there must be some design issues that doesn't let them move the cab way back.
For a trial machine - the first thing you want terrain to touch on your ride are the TIRES - front and rear, preferably to about 105° (15° past vertical....)
Actually the above video is a good study on off-road capability - approach and break over angles, etc.... - it also shows, that for an RV (...at the end the Terraliner will be solid RV, but an RV nevertheless), most of what you see you will never use that capability! You won't have recovery teams standing by, nor will you want to risk all your "apartment/home" gear getting thrown all over the place!!
So, as fantastic as they look and as capable as Expedition Vehicles may be - you about NEVER use that capability (...in an RV)!
If you don't do that - WHAT's the point building such a capability into your rig??
Your video reference shows EXACTLY my point - no real "near off-road" terrain, but going FAST capability over extremely rough roads. Military doesn't mind periodic high intensity maintenance (not part of THEIR efficiency concern).
Even if your rig (RV/Explorer) could do it, I doubt you would ACTUALLY run that fast on the same roads.....
Trial/Rally/War are different than RV/Exploring/Camping.....
And another one to reflect on your ACTUAL needs concerning off-road-able RVs! These are regular road-buses, with most likely no more than a locker in the rear axle, NO all wheel drive, and few that are slightly lifted. Look at the roads they negotiate and think about how much WORSE would you RISK to go - even if you have a monster trial/off-road rig.... https://www.youtube.com/watch?v=Adl5AsHBTh4
'nough said!
Cheers all,
thjakits
well, all nice banter here - nice ideas and all, but at SOME POINT you will have to settle on a path through the proposed project (..you already have a list and along this discussion you eliminated quite a few of your initial ideas, mainly when it comes to "proven", "simple", and weight issues...)
Though the TATRA system is NICE!! - it is NOT simple. Very capable, but IF you have trouble with it on the road (...we agreed to stay ON roads, right?), you are on your own - ....and the hopefully excellent long distance support from TATRA!
Unless you "have the need for speed!" - (which you will NOT have in a camper...) - the Independent suspension (latest Oshkosh or any other) will be overkill and more complex than you want.
Military needs/wants to go as fast as possible when on the move - make this more a "Rally"-like environment, the places you want to go with the Terraliner will want better ground clearance - like in SOLID AXLES.
A Solid Axle suspension with airbags will be able to be serviced about anywhere in the world and you won't notice any difference in ride comfort to any other suspension.....[ many proven 4x4s have/had solid axles at least until recently, Toyota Land Cruiser, Nissan Patrol, Land Rover, Mercedes-G, etc.... - why go for something complex if you don't need it??? - higger the vehicle the less harsh/bouncy a solid axle becomes - Just count the "moving links of a Solid Axle System versus a Independent System... All these links are usually bearings or rubber bushes or Poly-bushes - ALL of these eventually wear out and need replacing - make it as easy as possible!!]
Rollbars - if you already make a NEW Terraliner, might as well built these in - Carbon/kevlar monocoque box or steel space frame - "rollbars" INCLUDED INTO the structure. Just put a few "wear"-pieces on the outside!
Looking good and all martial - exo-cages/rollbars are DEFINITELY an aerodynamic no-no!! ON the long highway runs they will not help with economy.
I like the "Tatra Chassis with a Container"-idea, except - "integrating", as a top priority of Bio - ...would be seriously tough!
Also a 40/45 footer will weight in at better than 4 tons - ...then, you would have your rollbars included and have an excellent basis for slide-out construction all around! However you would have to build a complete new front end (cab) to somehow "integrate"....
Then - depending on price, a conventional chassis (like Campo's ride) might just be fine as well - if you mount the container solid! ....and you get "maintainability around the world" back!
ON the other hand you will always lose 4-tons of the overall weight just to the box! If that would be a good way to do it for a commercial product, all the established expedition vehicle builders would have done it long time ago (I am sure at some point they all did look at that possibility...]
Now - if your travel plans include politically less hospital areas - with a container as your walls - you are also save from lead laden air - you will need a .50 cal. or an RPG to get through the container!
If SERIAL-HYBRID is still a must in the requirements department - you might also forget about the TATRA chassis - there is TONS of gears in that system, eating up TONS of power along the way - The Tatra chassis is one big transmission that was stretched into a chassis!!
If your drive units are going to be electric you want to eliminate as many transmission-gears as possible to avoid transmission losses!
By the time you modified the TATRA chassis to that extend, there is not much left of it!
Then you might as well just build your own tube chassis with pendular axles and hub motors - back to the discussion about electric motors and efficiency!
Again - I think your best bet is to NOT push innovation for innovations sake!
Sometimes INNOVATION is mostly simplification and going back to basics!!
[As an excellent sample have a read-up on this: http://www.autospeed.com/cms/article.html?&A=111091 ...the gentleman discusses the merits of different suspension layouts for this particular application. To get to the optimum solution for a PARTICULAR case - you can't just copy/paste from others!]
Also - compare youtube stuff from the HUMMER/HUMVEE in the muck/off-road to others of similar size and purpose (Unimog, Volvo C303 to C306, Pinzgauer, etc....), and you will see that Independent Suspensions (Oshkosh style - Tatra/Pinzgauer pedular axles are different......) in these situations are quite limited!
And mostly not by traction - you can get that by proper tire choice and loads of lockers (...see Tatra and Pinzgauer - will have a wheel in the air quite often!) . It is the chassis that mainly gets in the way!
Nice articulation at every wheel with the independent suspension, but it does not lift the bottom of the car out of the way of obstacles!!
Just to throw it into the discussion: You should think about not taking it too seriously with the "Rigid Frame" requirement.
As a fact, there is no such thing! EVERYTHING flexes! Tatra and MAN/KAT are just closer to the rigid edge, Unimog (e.g.) closer to the flexible edge (...on purpose!).
Have also a look into aviation - airliners would NOT be possible if designed with as a much rigidity as possible - they would break up shortly!
[Ever observed a wing on take-off? Tips are WAY up long before the liner gets off the wheels! Also look at the wings in flight: Quite scary to see them bounce around!! No worries - they are DESIGNED for that!]
Very simply said: The stiffer something is the worse the failure mode: compare a metal can of fruit (bend the top or the can as you wish - you will get tired before it BREAKS!) - now, do the same to a piece of glass!! You can't bend it even 5% of the amount you bent the can! ....and the failure mode is - "catastrophic"! Of course these are the extreme samples, but the idea holds throughout every engineering application!
A big rig WILL flex! ....OR it WILL be HEAVY for rigidity .....OR complex (make that EXPENSIVE) to triangulate/sandwich/honeycomb the system....
The bigger units become the EXPONENTIALLY bigger/bigger become the rigidity deficits.....
So - you might want to think about building smaller "rigid" modules and connect them with a specific amount of flex allowed.
Chassis-Living area interface!
Hey Free Radical: ...check out this vid: https://www.youtube.com/watch?v=GAU3349luk0
...you won't find a single Tatra - I bet it is because of the ridiculous front overhang these rigs have. The newer machines are loads better, but your sample video doesn't TATRA any good regarding off-road-ability!
And knowing how capable these off-roaders are building their rigs, there must be some design issues that doesn't let them move the cab way back.
For a trial machine - the first thing you want terrain to touch on your ride are the TIRES - front and rear, preferably to about 105° (15° past vertical....)
Actually the above video is a good study on off-road capability - approach and break over angles, etc.... - it also shows, that for an RV (...at the end the Terraliner will be solid RV, but an RV nevertheless), most of what you see you will never use that capability! You won't have recovery teams standing by, nor will you want to risk all your "apartment/home" gear getting thrown all over the place!!
So, as fantastic as they look and as capable as Expedition Vehicles may be - you about NEVER use that capability (...in an RV)!
If you don't do that - WHAT's the point building such a capability into your rig??
Your video reference shows EXACTLY my point - no real "near off-road" terrain, but going FAST capability over extremely rough roads. Military doesn't mind periodic high intensity maintenance (not part of THEIR efficiency concern).
Even if your rig (RV/Explorer) could do it, I doubt you would ACTUALLY run that fast on the same roads.....
Trial/Rally/War are different than RV/Exploring/Camping.....
And another one to reflect on your ACTUAL needs concerning off-road-able RVs! These are regular road-buses, with most likely no more than a locker in the rear axle, NO all wheel drive, and few that are slightly lifted. Look at the roads they negotiate and think about how much WORSE would you RISK to go - even if you have a monster trial/off-road rig.... https://www.youtube.com/watch?v=Adl5AsHBTh4
'nough said!
Cheers all,
thjakits
Last edited:
egn
Adventurer
The above comparison between TAK-4 and straigth axle is a bit misleading. I assume the vehicle with straight axle has only leave suspension, whereas TAK-4 has spring coils.
If you combine both you get the suspension of the MAN KAT with the advantages of both. :sombrero:
When it comes to the ride quality of MAN KAT I always tell the story that I once forgot the oil fill cap on the flat top of the engine. After a few km driving on a gravel road I had the feeling that I forgot something and stopped for checking. What should I say, the oil fill cap was still lying on top of the engine.
So I think that straight axle combined with spring coils is a good compromise when it comes to capabilities and comfort of a suspension.
If you combine both you get the suspension of the MAN KAT with the advantages of both. :sombrero:
When it comes to the ride quality of MAN KAT I always tell the story that I once forgot the oil fill cap on the flat top of the engine. After a few km driving on a gravel road I had the feeling that I forgot something and stopped for checking. What should I say, the oil fill cap was still lying on top of the engine.
So I think that straight axle combined with spring coils is a good compromise when it comes to capabilities and comfort of a suspension.
Last edited:
free radical
New member
JkkkU
And
I'm guessing those guys run whatever they can afford and since new rigs cost way too much to play in the dirt they buy old army or retired construction trucks
Im not fond of that long overhang either fortunately Tatra makes conventional cabs also
Tatra Jamal
http://youtu.be/YPWLC-p88Cs
http://youtu.be/fV3iiNPE-1g
Before Tatra Czech army had these old Pragas
Old Czech military Praga V3S
http://youtu.be/sZarbXx7qM4
http://youtu.be/2ALH01zCzVk
Here's something that may be of interest to you guys trying to cram lots of furniture into your tiny rigs space
Space saving furniture
http://youtu.be/9nljmEUeLbY
https://www.facebook.com/TATRATRUCKS/posts/733129246773483
The reason for those long cab overhangs is; those rigs were designed to carry long big loads such as ICBM missiles or expanding bridges,cranes and even tanks etc..
And
I'm guessing those guys run whatever they can afford and since new rigs cost way too much to play in the dirt they buy old army or retired construction trucks
Im not fond of that long overhang either fortunately Tatra makes conventional cabs also
Tatra Jamal
http://youtu.be/YPWLC-p88Cs
http://youtu.be/fV3iiNPE-1g
Before Tatra Czech army had these old Pragas
Old Czech military Praga V3S
http://youtu.be/sZarbXx7qM4
http://youtu.be/2ALH01zCzVk
Here's something that may be of interest to you guys trying to cram lots of furniture into your tiny rigs space
Space saving furniture
http://youtu.be/9nljmEUeLbY
https://www.facebook.com/TATRATRUCKS/posts/733129246773483
Last edited: