TerraLiner:12 m Globally Mobile Beach House/Class-A Crossover w 6x6 Hybrid Drivetrain
- Thread starter biotect
- Start date
OptimusP:
Oh Jesus! PLEASE - NO!!
The Alvis Stalwart mk2 Amphibious!!
http://en.wikipedia.org/wiki/Alvis_Stalwart
WHAT a machine!! ....and what a nightmare on the road!
I believe there are NO differentials between the wheels on either one side - drive out to a distributor-box on each side and from there to the 3 wheels on that side NO differentials lengthwise - as soon as you start to turn on hardtop you start to destroy the drive train!!
IF you could adapt diffs though - wow!
Actually one of those with hub-motors...:snorkel::sombrero: !!
BUT getting in and out through the roof only, gets old fast!!
OFF-road though it is/was propably the most versatile Amphib on the planet (...this size)
I believe it would have become a seriously mean machine if it's career wasn't to be cut short by the helicopter....
It could take to the air though!! -
Playing around:
Getting one ready for the great revival:
EXCELLENT description of the drive-train nightmare in there !!
Would be a great candidate for a Serial-Hybrid refurb with hub-motors!!
Probably the best ever straight of the drawing board "Bad Road Negotiator"!
Suzuki Samurai/Jimny
...put on some AT or MT tires and you are good to go!!
ANYTHING else you do to the rig is just icing on the cake!
IS:
Looking good - BUT still there is more obstacle-catching stuff underneath than on a SA.
In these pictures the IS system is not at too steep an angle - BUT also doesn't have ground clearance any better than SA.
Here the rig is probably 1/2 in the air and the suspension is drooping fully - steep suspension angles - on "touch down" it will force the tires laterally to the outside.
Doesn't matter on this terrain - matters a LOT if you are slow in rocky terrain - to the point where the tires actually can lock up the suspension agaist a rock face....
And what is the most deciding factor for me is - going slow, when only one wheel rises the center of the vehicle stays low for a long part of the wheel travel, before it starts to lift the body. Part of the intend of IS is exactly that feature - keep the CAR-(body) as undisturbed by road imperfections as possible - let wheel ride over it and return to the normal level.
Great for cars and in Rally like applications, where you hardly ever encounter actual obstacles taller than the ground-clearance.
In areas where you need to clear SERIOUS obstacles (where Rally speeds would destroy everything....) at slow speed - the IS-forte becomes detrimental....
Absolutely good and valid point FOR IS! This is why you bring along SOME toy to explore where you cannot/wantnot go with the big rig.
However, I believe the Spec wishlist for Terraliner want's to go further in to "terrain" than you are willing to risk your ride....
For me personally - after seeing the Rally rigs "fly" with SA - I think I would stick with SA for their simplicity and rather get more sophistication into the springing and damping - still way less link/joint count...
[Any Full Size Truck IS I saw so far is essentially double wishbone layout - LOTS of joints....]
BIO:
ANYTHING that shows the TAK-4 suspension has the suspension-arms essentially straight out - level with the ground (but for a very shallow angle)
A it is - SA WILL have better ground clearance compared to the TAK-4.
Ridequality better than SA - ...WHAT are we comparing??
I don't see any TAK-4 equipped vehicle leaving the ground - so ride-comfort doesn NOT depend on unsprung weight, but only on proper springing/damping.
The TAK-4 lite is about the same as the original Humvee - propably with better geometry and springing/damping - gives a way better ride, but doesn not improve off-road prowess at all!
Remember - these guys are in the business to make money - and will promote their product at any price!!
To investigate and compare is up to the customer!
[Note, that they do not claim any better ground clearance or off-road ability - they really just claim a better ride, which is great if that is what they need! HOWEVER SA equipped vehicles could just as easy be improved on the ride quality! Military is big business and corruption - ....]
thjakits
Oh Jesus! PLEASE - NO!!
The Alvis Stalwart mk2 Amphibious!!
http://en.wikipedia.org/wiki/Alvis_Stalwart
WHAT a machine!! ....and what a nightmare on the road!
I believe there are NO differentials between the wheels on either one side - drive out to a distributor-box on each side and from there to the 3 wheels on that side NO differentials lengthwise - as soon as you start to turn on hardtop you start to destroy the drive train!!
IF you could adapt diffs though - wow!
Actually one of those with hub-motors...:snorkel::sombrero: !!
BUT getting in and out through the roof only, gets old fast!!
OFF-road though it is/was propably the most versatile Amphib on the planet (...this size)
I believe it would have become a seriously mean machine if it's career wasn't to be cut short by the helicopter....
It could take to the air though!! -
Playing around:
Getting one ready for the great revival:
EXCELLENT description of the drive-train nightmare in there !!
Would be a great candidate for a Serial-Hybrid refurb with hub-motors!!
Probably the best ever straight of the drawing board "Bad Road Negotiator"!
Suzuki Samurai/Jimny
...put on some AT or MT tires and you are good to go!!
ANYTHING else you do to the rig is just icing on the cake!
IS:
Looking good - BUT still there is more obstacle-catching stuff underneath than on a SA.
In these pictures the IS system is not at too steep an angle - BUT also doesn't have ground clearance any better than SA.
Here the rig is probably 1/2 in the air and the suspension is drooping fully - steep suspension angles - on "touch down" it will force the tires laterally to the outside.
Doesn't matter on this terrain - matters a LOT if you are slow in rocky terrain - to the point where the tires actually can lock up the suspension agaist a rock face....
And what is the most deciding factor for me is - going slow, when only one wheel rises the center of the vehicle stays low for a long part of the wheel travel, before it starts to lift the body. Part of the intend of IS is exactly that feature - keep the CAR-(body) as undisturbed by road imperfections as possible - let wheel ride over it and return to the normal level.
Great for cars and in Rally like applications, where you hardly ever encounter actual obstacles taller than the ground-clearance.
In areas where you need to clear SERIOUS obstacles (where Rally speeds would destroy everything....) at slow speed - the IS-forte becomes detrimental....
Absolutely good and valid point FOR IS! This is why you bring along SOME toy to explore where you cannot/wantnot go with the big rig.
However, I believe the Spec wishlist for Terraliner want's to go further in to "terrain" than you are willing to risk your ride....
For me personally - after seeing the Rally rigs "fly" with SA - I think I would stick with SA for their simplicity and rather get more sophistication into the springing and damping - still way less link/joint count...
[Any Full Size Truck IS I saw so far is essentially double wishbone layout - LOTS of joints....]
BIO:
ANYTHING that shows the TAK-4 suspension has the suspension-arms essentially straight out - level with the ground (but for a very shallow angle)
A it is - SA WILL have better ground clearance compared to the TAK-4.
Ridequality better than SA - ...WHAT are we comparing??
I don't see any TAK-4 equipped vehicle leaving the ground - so ride-comfort doesn NOT depend on unsprung weight, but only on proper springing/damping.
The TAK-4 lite is about the same as the original Humvee - propably with better geometry and springing/damping - gives a way better ride, but doesn not improve off-road prowess at all!
Remember - these guys are in the business to make money - and will promote their product at any price!!
To investigate and compare is up to the customer!
[Note, that they do not claim any better ground clearance or off-road ability - they really just claim a better ride, which is great if that is what they need! HOWEVER SA equipped vehicles could just as easy be improved on the ride quality! Military is big business and corruption - ....]
thjakits
Last edited:
NeverEnough
Adventurer
It sure would be good to hear from campo and NeverEnough as well on this issue.....
I'm assuming the IS v SA debate. Honestly, it's like watching my wife make a decision! I truly wish I had sufficient knowledge to add something profound, but I don't, especially without a budget to guide me. The only observation I will add to my IS bias is that, from my limited view, IS seems to be getting the lion's share of suspension engineering R&D resources, increasingly in the heavy truck world. Some of the reasons for that might matter for this project, others may not. More importantly, either suspension can be engineered to meet the requirements of this project. But, as somebody mentioned a while back, best to get some of these big decisions behind you if you want to move forward.
For what it's worth, I used 6 leveling jacks instead of four because 4 lift the "camper" off the truck. The other two are up front of the forward axle because because of 1) the forward nature of the CG (it would teeter-toter if I didn't have a pair up front), 2) weight:jack ratio (rated at 7500lbs each, not enough so I'm going to beef them up this year). They're electric, not hydraulic, and that's been a good decision (screw)- easy system to maintain/service, small footprint, simple, and provides bi-directional functionality, just eats a lot of amps.
And the International 7400 4x4 is a SFA SA, leaf springs up front, air in the back, with cab air-ride. It rides great on the highway, great on washboard, painfully slow on ruts and cobble.
biotect
Designer
..
Hi NeverEnough,
I've been "moving forward" in any case, because the IS versus SA debate does not really affect my design decisions for the camper box all that much. Whereas axle-placement does have a big impact. But once I realized that even in a tandem arrangement, the inter-axle distance and breakover angle on a 6x6 would be much, much better than most of the currently operating 4x4 commercial overlanding trucks (Oasis, Dragoman, Odyssey, etc.), I ditched the idea of equal axle spacing. And from a design point of view, the tandem arrangement (i.e. two axles clustered in back, but not too closely together) serves my purposes well.
So most of this discussion, although important from an engineering point of view, does not really impact my design decisions. I am only engaging in the SA versus IS debate, and drawing it out a bit, because I am learning a great deal. And in the final project presentation I eventually do want to clearly specify my choice, SA or IS, and justify my decision.
It was also good to realize just how problematic electric hub-motors would be on a corrugated road surface. As thjakits and optimusprime have pointed out, dirt and water are not really the problem. Rather, the problem will be vibration and shocks when traveling bad corrugated roads like the Tanami Track in Australia. dwh made the same point:
So Haf-E and dwh are right: the best arrangement is three E-motors driving three axles, with the E-motors up and out of the way, benefitting from the smooth ride provided by the right choice of suspension. But I am assuming that Haf-E's three-motor solution would still prove perfectly compatible with either IS or SA; that installing three E-motors does not automatically mean they are driving three Solid Axles.
As for watching your wife make a decision..... Have you ever wondered why it takes on average 4 years for a new car to get to market, from initial design conception to final product? Every design and engineering decision is reviewed and reviewed again, and having bean-counters with budget considerations in the mix only makes things more complicated, not less.
All best wishes,
Biotect
Hi NeverEnough,
I've been "moving forward" in any case, because the IS versus SA debate does not really affect my design decisions for the camper box all that much. Whereas axle-placement does have a big impact. But once I realized that even in a tandem arrangement, the inter-axle distance and breakover angle on a 6x6 would be much, much better than most of the currently operating 4x4 commercial overlanding trucks (Oasis, Dragoman, Odyssey, etc.), I ditched the idea of equal axle spacing. And from a design point of view, the tandem arrangement (i.e. two axles clustered in back, but not too closely together) serves my purposes well.
So most of this discussion, although important from an engineering point of view, does not really impact my design decisions. I am only engaging in the SA versus IS debate, and drawing it out a bit, because I am learning a great deal. And in the final project presentation I eventually do want to clearly specify my choice, SA or IS, and justify my decision.
It was also good to realize just how problematic electric hub-motors would be on a corrugated road surface. As thjakits and optimusprime have pointed out, dirt and water are not really the problem. Rather, the problem will be vibration and shocks when traveling bad corrugated roads like the Tanami Track in Australia. dwh made the same point:
So Haf-E and dwh are right: the best arrangement is three E-motors driving three axles, with the E-motors up and out of the way, benefitting from the smooth ride provided by the right choice of suspension. But I am assuming that Haf-E's three-motor solution would still prove perfectly compatible with either IS or SA; that installing three E-motors does not automatically mean they are driving three Solid Axles.
As for watching your wife make a decision..... Have you ever wondered why it takes on average 4 years for a new car to get to market, from initial design conception to final product? Every design and engineering decision is reviewed and reviewed again, and having bean-counters with budget considerations in the mix only makes things more complicated, not less.
All best wishes,
Biotect
Last edited:
biotect
Designer
...
Hi dwh,
Yes, I can see how portals might be good to have. From a design point of view, the issue is that the tubular space-frame has to start somewhere. And above that, the floor of the camper box also has to start somewhere. So the more center-line clearance one provides, the less space there might be for a battery bank, for instance, underneath the floor. But I agree very much that deeply rutted roads are the biggest “obstacle” that a bad-road vehicle like the TerraLiner will encounter. So centerline clearance is an important issue.
Perhaps I should put the question to you this way: how much clearance do you think the TerraLiner really needs, or should have, down the centerline? If the TerraLiner has straight axles without portals, of course the answer will be the diameter of the tires, minus a bit, so 50 cm or so. Do you think this is insufficient? What would you consider the ideal figure, and why?
And anyone else reading this who has overlanding experience: what should be the ideal centerline clearance of a large 6x6 motorhome like the TerraLiner, so that it would have no problem negotiating even the most deeply rutted bad roads?
As for off-the-shelf live axles and off-the-shelf portals: these do not have to be off-the shelf. Remember, it's a concept vehicle. So if portals specifically engineered for higher speeds and a non-Unimog set of application parameters seem desirable, then portals should be included. It all depends on what everyone thinks would or should be an “ideal” centerline clearance.
And needless to say, from a design point of view centerline clearance is actually much more important than the IS versus SA debate. Because centerline clearance affects overall camper box height and volume. With higher clearance, there's less room for the camper box. So swift responses with specific numbers from all and sundry (60 cm, 70 cm, 80 cm....) would be much appreciated!! Ideally illustrated with images of rutted roads and/or links to websites providing good rationales for the numbers proposed.
All best wishes,
Biotect
Hi dwh,
Yes, I can see how portals might be good to have. From a design point of view, the issue is that the tubular space-frame has to start somewhere. And above that, the floor of the camper box also has to start somewhere. So the more center-line clearance one provides, the less space there might be for a battery bank, for instance, underneath the floor. But I agree very much that deeply rutted roads are the biggest “obstacle” that a bad-road vehicle like the TerraLiner will encounter. So centerline clearance is an important issue.
Perhaps I should put the question to you this way: how much clearance do you think the TerraLiner really needs, or should have, down the centerline? If the TerraLiner has straight axles without portals, of course the answer will be the diameter of the tires, minus a bit, so 50 cm or so. Do you think this is insufficient? What would you consider the ideal figure, and why?
And anyone else reading this who has overlanding experience: what should be the ideal centerline clearance of a large 6x6 motorhome like the TerraLiner, so that it would have no problem negotiating even the most deeply rutted bad roads?
As for off-the-shelf live axles and off-the-shelf portals: these do not have to be off-the shelf. Remember, it's a concept vehicle. So if portals specifically engineered for higher speeds and a non-Unimog set of application parameters seem desirable, then portals should be included. It all depends on what everyone thinks would or should be an “ideal” centerline clearance.
And needless to say, from a design point of view centerline clearance is actually much more important than the IS versus SA debate. Because centerline clearance affects overall camper box height and volume. With higher clearance, there's less room for the camper box. So swift responses with specific numbers from all and sundry (60 cm, 70 cm, 80 cm....) would be much appreciated!! Ideally illustrated with images of rutted roads and/or links to websites providing good rationales for the numbers proposed.
All best wishes,
Biotect
Last edited:
biotect
Designer
Hi thjakits,
In quick point-form, in response to your most recent posts, over the last three or four pages:
(1) Here I agree with you, just not regarding the hub-motors part. With Haf-E’s three-motor proposal, there is no reason why all axles and all motors would have to be active all the time. As you rightly suggest, only one “main” motor should be active for most highway driving. All three motors would be chassis-mounted and protected from vibration. But perhaps as you suggest they should be different sizes. You suggested 420 KW overall, so how would you “parse” this power requirement? Two motors 100 KW, and a main drive motor 220 KW?
And of course, now that we’re all agreed on the three-motor solution (at least we’ve agreed on this much! ), electronic diff lockers are no longer an issue. Mechanical diff lockers are clearly the optimal solution.
So too, given the three-motor solution, there’s probably no need to debate hub motors mounted inside De-Dion tubes anymore….:coffeedrink:
As for hub motors and water, no worries. That’s not the main concern. As already suggested above in a post quoting dwh, the main concern is shock and vibration. Mounting the electric motors on the chassis ensures that they are relatively insulated from shock and vibration. The Tanami Trail breaks axles; it will probably break electric hub motors, too. Haf-E made the same point. It just seems a complete mistake to put electric hub motors in an overlanding vehicle, even though engineering-lite concept designs like the "OEX-B" by Bekradi, or the “Nimbus” and “Troy” by Galvani, stipulate as much.
Oshkosh’s diesel-electric solutions all seem to mount the electric motors on the chassis, and not in the wheels, and no doubt Oshkosh's reasoning about this issue was the same.
************************************************
(2) Again, about that 420 KW: you are referring to the total power of the electric motors, right? Not the generator output? So in terms of HP, what I’ve just proposed would mean two electric motors 134 HP each, and one producing about 300 HP – see http://www.rapidtables.com/convert/power/kw-to-hp.htm .
You also proposed that the diesel engine should produce 300 KW, or 400 HP. Same question as I asked earlier: is this the proposed power rating of the diesel engine? Or the KW power output of the attached generator? These will be different, and the KW output of the generator will be lower.
Here the assumption is that a large battery bank will drain more quickly than it’s charged by the 300 KW generator, if all 420 KW of electric motor power were being used. So just a speculative question: how big do you think the diesel engine would have to be, if no battery were intervening at all, as per the Pisten Bully 600 E+ posted earlier in the thread? 420 KW is 563 HP, so certainly at least as big as that, right??? But power is lost via the generator, so…..?
************************************************
(3) Many thanks for the suggestions about the modular approach to construction, and designing so that the TerraLiner could be buildable 8 m to 12 m. That’s a nice way of thinking about it, although 12 m sound just way too big….:sombrero:
************************************************
(4) Interesting comment about there being no need for an auxiliary 20 KW unit; rather, what's needed is proper alignment between main generator output and the size of the battery bank.
However, here I am thinking of egn’s earlier comments in the thread about the insufficiency of the Earthroamer dual-alternator solution. Earthroamer does not provide diesel generators in its expedition motorhomes, because it claims that it’s better to just charge the batteries with dual alternators off the main engine. But as egn and others have pointed out (e.g. Julius), “idling” when parked is illegal in some countries. Whereas running a very silent and sound-protected diesel generator would not be. So egn was quite adamant that the Earthroamer “anti auxiliary generator” stance seemed completely wrong-headed.
What you are in effect proposing by eliminating the 20 KW auxiliary unit is something roughly equivalent to the Earthroamer position. That’s why I’m a bit wary of eliminating the extra 20 KW generator.
Now agreed, the main engine/generator should be soundproofed as much as might prove feasible. And perhaps because it’s not a “real” diesel engine, and actually a generator instead, existing legal constraints would not apply?
************************************************
(5) Glad to see that you like the “engine/generator on a slide out tray” idea. That modularity alone would be very attractive, because the mechanical engine will probably be the most fault-prone element in the whole system. MAN designs its SX series trucks to have a service life of 30 years, but one wonders whether this includes the engine?
So in principle everything else in the TerraLiner could be just as robust as a MAN SX, especially the overall structure. Built as solid as the 1950’s Airstream trailers that are still in use today. But of course much lighter, because made of titanium and carbon fiber. Just the diesel generator and differentials might have a shorter shelf-life. Within the camper box, of course, other systems (water, heat, etc.) are another story.
************************************************
(6) Interesting thoughts about the problem of equally spaced axles going over a ridge, and the need to “bias” in favor of either 1 + 2, or 2 + 1. I am now definitely favoring a 1 + 2 tandem arrangement, but I appreciate your thoughts about the advantages of a 2 + 1, and all the great images of old trucks that have the first two axles clustered in front, as well as the gallery of newer trucks that have the same. And I do appreciate the engineering advantages of two steerable axles clustered in front (with 100 KW electric motors), and the main drive axle in back (with a 220 KW electric motor).
egn advocated just such a “castrated” 8x8 earlier in the thread: an 8x8 MAN-KAT with its last axle cut off. But his main concern seems to have been getting the weight distribution across the axles right, because the MAN-KAT's heavy engine and transmission are up front. So having two axles clustered up front, instead of clustered in back, makes more sense. In the TerraLiner this won’t be such a big consideration, however, because the engine/generator won’t weigh nearly as much as a MAN-KAT engine + its huge transmission. And the weight of the lithium-ion batteries and the electric motors will be distributed more evenly throughout the vehicle.
Furthermore, there are camper-box design reasons why I prefer a more standard tandem arrangement instead. But as you suggested in one image, the two rear axles could be widely spaced:
And yes, the third axle would definitely have to be steerable.
************************************************
(7) Very interesting thoughts about having an air-suspension that allows the vehicle to adjust to different road conditions, changing the center-line clearance. Agreed, when travelling on highways, best to reduce the center-line clearance and “hug” the road; and quite the opposite when travelling bad roads with deep ruts.
As per the question already asked above, in the post just previous to this one, what do you then think should be the maximal center-line clearance? 60 cm? 70 cm? 80 cm? Here assuming that portals could supplement the roughly 60 cm above-grade tire-centers of big Michelins.
************************************************
(8) Very interesting thoughts about eliminating hydraulics completely, and having both leveling jacks as well as the Pop-Up raised/lowered electrically. That certainly has been the direction in slide-outs: most recent slide-outs are now worm-gear driven. Whereas when slide-outs first appeared, they were hydraulically extended.
************************************************
(9) Brakes: perhaps Carbon-Ceramic brakes from Brembo? See http://www.brembo.com/en/car/Pages/default.aspx , http://www.brembo.com/en/car/original-equipment/products/Pages/Carbon ceramic discs.aspx , http://www.carbonceramicbrakes.com/en/Pages/default.aspx , and http://www.autoguide.com/auto-news/...houldnt-upgrade-to-carbon-ceramic-brakes.html
[video=youtube;lZ2id1mb5sg]https://www.youtube.com/watch?v=lZ2id1mb5sg [/video]
Does anyone know whether these exist yet for trucks? I’ve read that Carbon-Ceramic brakes last much, much longer than traditional brakes, dramatically increasing the time-span between brake replacements/repairs. Which would be a good thing for a TerraLiner.
************************************************
(10) Interesting comment about the rather uninteresting routes taken by most commercial overlanding companies, thereby eliminating the need for good breakover angles in their vehicles. That explains a lot. Still, the TerraLiner is not intended as an off-road motorhome, just bad-road, so after seeing those vehicles, I do feel that I can relax a bit more about axle placement, and inter-axle distances.
Note that the one exception might be “Aminah”, the blue commercial overlanding truck used by Overlanding West Africa. The roads Aminah travels do look quite challenging, and yet its breakover angle, too, seems a lot worse than any of the 6x6 trucks I posted.
************************************************
(11) Perhaps this is a really stupid question: can portals work with Independent Suspension? Or is the natural pairing Straight-Axle + Portals?
************************************************
(12) Yes, these two concept drawings are definitely Art Deco-inspired:
But I still very much prefer the Kamm Coupé, in both its original and recent "hommage" versions:
The Kamm Coupé is less bombastic and more subtle than the concept illustrations you posted.
Also remember, I am not creating a vehicle that is just "Art Deco", 1930's style. Rather, my design target is retro-futurisitic Art Deco, as per the second row of images of the 2006 "hommage" -- see posts#677 to #682 , at http://www.expeditionportal.com/for...pedition-RV-w-Rigid-Torsion-Free-Frame/page68 and http://www.expeditionportal.com/for...pedition-RV-w-Rigid-Torsion-Free-Frame/page69 .
The Art-Deco era car that perhaps comes closest to the concept drawing you posted, thjakits, is the French/Spanish 1938 Hispano-Suiza Dubonnet Xenia, covered at length by Jay Leno's Garage:
And see http://www.wired.com/2011/03/feast-your-eyes-on-the-1938-hispano-suiza-dubonnet-xenia/ , http://www.thecoolist.com/1938-hispano-suiza-dubonnet-xenia/ , http://www.car-revs-daily.com/2014/...-suiza-h6c-xenia-at-mullin-automotive-museum/ , http://www.conceptcarz.com/vehicle/z9210/Hispano-Suiza-H6C.aspx , http://www.supercars.net/cars/2895.html , http://en.wikipedia.org/wiki/André_Dubonnet , http://en.wikipedia.org/wiki/Dubonnet_suspension , http://velocityjournal.com/journal/1938/hispanosuiza/2820/pictures.html , http://www.oobject.com/sky-captain-gadgets-vehicles/1938-hispano-suiza-h6c-dubonnet-xenia/1076/ , and http://www.coachbuild.com/gallery/main.php?g2_itemId=29406 .
But if you watch the video, you'll see that the detailing in the Hispano-Suiza Dubonnet is much more sophisticated, and again, much more subtle, than the detailing offered in the concept drawing you posted. It also has wickedly cool doors, perhaps the most original car doors I have yet seen.
************************************************
(13) “Three Dimensional Philosopher of the Future” – I like the sound of that. :sombrero: .. Even if I am not particularly fond of Colani’s designs…..
************************************************
(14) Thanks for the super-cool video about regenerative braking in Bosch’s parallel hybrid system. So cool, it deserves to be posted again:
[video=youtube;gX7DUiO3PLI]https://www.youtube.com/watch?v=gX7DUiO3PLI#t=182 [/video]
Of course regenerative braking has to be part of the system, with the electric motors switching over to act as generators. I posted something earlier in the thread on the topic, and some links to websites that explained that although simple in concept, in actual practice a bit more complicated to implement – see http://auto.howstuffworks.com/auto-parts/brakes/brake-types/regenerative-braking1.htm and http://auto.howstuffworks.com/auto-parts/brakes/brake-types/regenerative-braking3.htm .
************************************************
(15) A super-fascinating proposal for an electric rock-crawler “Little Explorer” that could be carried inside the Oshkosh trailer…... Again, the link you provided at http://www.diyelectriccar.com/forums/showthread.php/motor-help-needed-hybrid-rock-crawler-50729.html .
************************************************
(16) Where did you find the image of that integrated MAN-KAT?
Do you have a weblink? I will do a google image-search if you don’t, but would like to know more about it.
************************************************
(17) Nice pics illustrating the problems of TATRA swing-axles…..
************************************************
(18) Optimus: that YouTube video of an amphibious vehicle taking a big dive is simply hilarious:
[video=youtube;3mr_pCrhTkk]https://www.youtube.com/watch?v=3mr_pCrhTkk&feature=youtu.be [/video]
And thanks, thjakits, for providing all the background info about this vehicle in post #1114, at http://www.expeditionportal.com/for...edition-RV-w-Rigid-Torsion-Free-Frame/page112 .
************************************************
(19) Finally, as regards your most recent thoughts about TAK-4: see the posts above, #1106 to #1112, and let me know what you think.
I liked your summary of the basic principle behind IS:
And I do agree that the real issue for drive comfort is proper springing/damping, i.e. coil + air suspension (most probably). But kinetic and hydro-pneumatic still open for consideration…..:ylsmoke:
As regards TAK-4 and Independent Suspension, I am playing devil’s advocate for the most part. I am still strongly inclined in the direction of Straight Axle. And you have convinced me that with coil springs + air suspension, Straight Axle can provide a really nice ride, especially in a 6x6. In fact, egn convinced me about this quite a while back. egn recounted a story about forgetting to put the gas-cap back on. He left it on a ledge on his vehicle, Blue Thunder; drove Blue Thunder about 100 km over some very rough terrain; and when he stopped, the gas-cap was still sitting where he left it.
Pretty much the only thing I have “concerns” about, regarding SA, is the turning radius. The G-wagen has a notoriously wretched turning radius because it’s SA. Oshkosh emphasizes the turning radius advantages of IS in the following video:
In the next few posts I will discuss the L-ATV a bit more, and post some more images. But don’t misunderstand my intent. I just wanted IS to get a bit more “air time”, before we decide 200 % against it.
Otherwise, many thanks for all the feedback: it is proving invaluable, and I certainly am learning a great deal. At least when the final project appears, nobody will be able to say that I paid insufficient attention to important engineering and overlanding basics, and that the resulting vehicle is wholly "unrealistic" or "impractical". Keep it coming!
All best wishes,
Biotect
In quick point-form, in response to your most recent posts, over the last three or four pages:
(1) Here I agree with you, just not regarding the hub-motors part. With Haf-E’s three-motor proposal, there is no reason why all axles and all motors would have to be active all the time. As you rightly suggest, only one “main” motor should be active for most highway driving. All three motors would be chassis-mounted and protected from vibration. But perhaps as you suggest they should be different sizes. You suggested 420 KW overall, so how would you “parse” this power requirement? Two motors 100 KW, and a main drive motor 220 KW?
And of course, now that we’re all agreed on the three-motor solution (at least we’ve agreed on this much!
), electronic diff lockers are no longer an issue. Mechanical diff lockers are clearly the optimal solution.So too, given the three-motor solution, there’s probably no need to debate hub motors mounted inside De-Dion tubes anymore….:coffeedrink:
As for hub motors and water, no worries. That’s not the main concern. As already suggested above in a post quoting dwh, the main concern is shock and vibration. Mounting the electric motors on the chassis ensures that they are relatively insulated from shock and vibration. The Tanami Trail breaks axles; it will probably break electric hub motors, too. Haf-E made the same point. It just seems a complete mistake to put electric hub motors in an overlanding vehicle, even though engineering-lite concept designs like the "OEX-B" by Bekradi, or the “Nimbus” and “Troy” by Galvani, stipulate as much.
Oshkosh’s diesel-electric solutions all seem to mount the electric motors on the chassis, and not in the wheels, and no doubt Oshkosh's reasoning about this issue was the same.
************************************************
(2) Again, about that 420 KW: you are referring to the total power of the electric motors, right? Not the generator output? So in terms of HP, what I’ve just proposed would mean two electric motors 134 HP each, and one producing about 300 HP – see http://www.rapidtables.com/convert/power/kw-to-hp.htm .
You also proposed that the diesel engine should produce 300 KW, or 400 HP. Same question as I asked earlier: is this the proposed power rating of the diesel engine? Or the KW power output of the attached generator? These will be different, and the KW output of the generator will be lower.
Here the assumption is that a large battery bank will drain more quickly than it’s charged by the 300 KW generator, if all 420 KW of electric motor power were being used. So just a speculative question: how big do you think the diesel engine would have to be, if no battery were intervening at all, as per the Pisten Bully 600 E+ posted earlier in the thread? 420 KW is 563 HP, so certainly at least as big as that, right??? But power is lost via the generator, so…..?
************************************************
(3) Many thanks for the suggestions about the modular approach to construction, and designing so that the TerraLiner could be buildable 8 m to 12 m. That’s a nice way of thinking about it, although 12 m sound just way too big….:sombrero:
************************************************
(4) Interesting comment about there being no need for an auxiliary 20 KW unit; rather, what's needed is proper alignment between main generator output and the size of the battery bank.
However, here I am thinking of egn’s earlier comments in the thread about the insufficiency of the Earthroamer dual-alternator solution. Earthroamer does not provide diesel generators in its expedition motorhomes, because it claims that it’s better to just charge the batteries with dual alternators off the main engine. But as egn and others have pointed out (e.g. Julius), “idling” when parked is illegal in some countries. Whereas running a very silent and sound-protected diesel generator would not be. So egn was quite adamant that the Earthroamer “anti auxiliary generator” stance seemed completely wrong-headed.
What you are in effect proposing by eliminating the 20 KW auxiliary unit is something roughly equivalent to the Earthroamer position. That’s why I’m a bit wary of eliminating the extra 20 KW generator.
Now agreed, the main engine/generator should be soundproofed as much as might prove feasible. And perhaps because it’s not a “real” diesel engine, and actually a generator instead, existing legal constraints would not apply?
************************************************
(5) Glad to see that you like the “engine/generator on a slide out tray” idea. That modularity alone would be very attractive, because the mechanical engine will probably be the most fault-prone element in the whole system. MAN designs its SX series trucks to have a service life of 30 years, but one wonders whether this includes the engine?
So in principle everything else in the TerraLiner could be just as robust as a MAN SX, especially the overall structure. Built as solid as the 1950’s Airstream trailers that are still in use today. But of course much lighter, because made of titanium and carbon fiber. Just the diesel generator and differentials might have a shorter shelf-life. Within the camper box, of course, other systems (water, heat, etc.) are another story.
************************************************
(6) Interesting thoughts about the problem of equally spaced axles going over a ridge, and the need to “bias” in favor of either 1 + 2, or 2 + 1. I am now definitely favoring a 1 + 2 tandem arrangement, but I appreciate your thoughts about the advantages of a 2 + 1, and all the great images of old trucks that have the first two axles clustered in front, as well as the gallery of newer trucks that have the same. And I do appreciate the engineering advantages of two steerable axles clustered in front (with 100 KW electric motors), and the main drive axle in back (with a 220 KW electric motor).
egn advocated just such a “castrated” 8x8 earlier in the thread: an 8x8 MAN-KAT with its last axle cut off. But his main concern seems to have been getting the weight distribution across the axles right, because the MAN-KAT's heavy engine and transmission are up front. So having two axles clustered up front, instead of clustered in back, makes more sense. In the TerraLiner this won’t be such a big consideration, however, because the engine/generator won’t weigh nearly as much as a MAN-KAT engine + its huge transmission. And the weight of the lithium-ion batteries and the electric motors will be distributed more evenly throughout the vehicle.
Furthermore, there are camper-box design reasons why I prefer a more standard tandem arrangement instead. But as you suggested in one image, the two rear axles could be widely spaced:
And yes, the third axle would definitely have to be steerable.
************************************************
(7) Very interesting thoughts about having an air-suspension that allows the vehicle to adjust to different road conditions, changing the center-line clearance. Agreed, when travelling on highways, best to reduce the center-line clearance and “hug” the road; and quite the opposite when travelling bad roads with deep ruts.
As per the question already asked above, in the post just previous to this one, what do you then think should be the maximal center-line clearance? 60 cm? 70 cm? 80 cm? Here assuming that portals could supplement the roughly 60 cm above-grade tire-centers of big Michelins.
************************************************
(8) Very interesting thoughts about eliminating hydraulics completely, and having both leveling jacks as well as the Pop-Up raised/lowered electrically. That certainly has been the direction in slide-outs: most recent slide-outs are now worm-gear driven. Whereas when slide-outs first appeared, they were hydraulically extended.
************************************************
(9) Brakes: perhaps Carbon-Ceramic brakes from Brembo? See http://www.brembo.com/en/car/Pages/default.aspx , http://www.brembo.com/en/car/original-equipment/products/Pages/Carbon ceramic discs.aspx , http://www.carbonceramicbrakes.com/en/Pages/default.aspx , and http://www.autoguide.com/auto-news/...houldnt-upgrade-to-carbon-ceramic-brakes.html
[video=youtube;lZ2id1mb5sg]https://www.youtube.com/watch?v=lZ2id1mb5sg [/video]
Does anyone know whether these exist yet for trucks? I’ve read that Carbon-Ceramic brakes last much, much longer than traditional brakes, dramatically increasing the time-span between brake replacements/repairs. Which would be a good thing for a TerraLiner.
************************************************
(10) Interesting comment about the rather uninteresting routes taken by most commercial overlanding companies, thereby eliminating the need for good breakover angles in their vehicles. That explains a lot. Still, the TerraLiner is not intended as an off-road motorhome, just bad-road, so after seeing those vehicles, I do feel that I can relax a bit more about axle placement, and inter-axle distances.
Note that the one exception might be “Aminah”, the blue commercial overlanding truck used by Overlanding West Africa. The roads Aminah travels do look quite challenging, and yet its breakover angle, too, seems a lot worse than any of the 6x6 trucks I posted.
************************************************
(11) Perhaps this is a really stupid question: can portals work with Independent Suspension? Or is the natural pairing Straight-Axle + Portals?
************************************************
(12) Yes, these two concept drawings are definitely Art Deco-inspired:
But I still very much prefer the Kamm Coupé, in both its original and recent "hommage" versions:
The Kamm Coupé is less bombastic and more subtle than the concept illustrations you posted.
Also remember, I am not creating a vehicle that is just "Art Deco", 1930's style. Rather, my design target is retro-futurisitic Art Deco, as per the second row of images of the 2006 "hommage" -- see posts#677 to #682 , at http://www.expeditionportal.com/for...pedition-RV-w-Rigid-Torsion-Free-Frame/page68 and http://www.expeditionportal.com/for...pedition-RV-w-Rigid-Torsion-Free-Frame/page69 .
The Art-Deco era car that perhaps comes closest to the concept drawing you posted, thjakits, is the French/Spanish 1938 Hispano-Suiza Dubonnet Xenia, covered at length by Jay Leno's Garage:
And see http://www.wired.com/2011/03/feast-your-eyes-on-the-1938-hispano-suiza-dubonnet-xenia/ , http://www.thecoolist.com/1938-hispano-suiza-dubonnet-xenia/ , http://www.car-revs-daily.com/2014/...-suiza-h6c-xenia-at-mullin-automotive-museum/ , http://www.conceptcarz.com/vehicle/z9210/Hispano-Suiza-H6C.aspx , http://www.supercars.net/cars/2895.html , http://en.wikipedia.org/wiki/André_Dubonnet , http://en.wikipedia.org/wiki/Dubonnet_suspension , http://velocityjournal.com/journal/1938/hispanosuiza/2820/pictures.html , http://www.oobject.com/sky-captain-gadgets-vehicles/1938-hispano-suiza-h6c-dubonnet-xenia/1076/ , and http://www.coachbuild.com/gallery/main.php?g2_itemId=29406 .
But if you watch the video, you'll see that the detailing in the Hispano-Suiza Dubonnet is much more sophisticated, and again, much more subtle, than the detailing offered in the concept drawing you posted. It also has wickedly cool doors, perhaps the most original car doors I have yet seen.
************************************************
(13) “Three Dimensional Philosopher of the Future” – I like the sound of that. :sombrero: .. Even if I am not particularly fond of Colani’s designs…..
************************************************
(14) Thanks for the super-cool video about regenerative braking in Bosch’s parallel hybrid system. So cool, it deserves to be posted again:
[video=youtube;gX7DUiO3PLI]https://www.youtube.com/watch?v=gX7DUiO3PLI#t=182 [/video]
Of course regenerative braking has to be part of the system, with the electric motors switching over to act as generators. I posted something earlier in the thread on the topic, and some links to websites that explained that although simple in concept, in actual practice a bit more complicated to implement – see http://auto.howstuffworks.com/auto-parts/brakes/brake-types/regenerative-braking1.htm and http://auto.howstuffworks.com/auto-parts/brakes/brake-types/regenerative-braking3.htm .
************************************************
(15) A super-fascinating proposal for an electric rock-crawler “Little Explorer” that could be carried inside the Oshkosh trailer…..
. Again, the link you provided at http://www.diyelectriccar.com/forums/showthread.php/motor-help-needed-hybrid-rock-crawler-50729.html . ************************************************
(16) Where did you find the image of that integrated MAN-KAT?
Do you have a weblink? I will do a google image-search if you don’t, but would like to know more about it.
************************************************
(17) Nice pics illustrating the problems of TATRA swing-axles…..
************************************************
(18) Optimus: that YouTube video of an amphibious vehicle taking a big dive is simply hilarious:
[video=youtube;3mr_pCrhTkk]https://www.youtube.com/watch?v=3mr_pCrhTkk&feature=youtu.be [/video]
And thanks, thjakits, for providing all the background info about this vehicle in post #1114, at http://www.expeditionportal.com/for...edition-RV-w-Rigid-Torsion-Free-Frame/page112 .
************************************************
(19) Finally, as regards your most recent thoughts about TAK-4: see the posts above, #1106 to #1112, and let me know what you think.
I liked your summary of the basic principle behind IS:
And I do agree that the real issue for drive comfort is proper springing/damping, i.e. coil + air suspension (most probably). But kinetic and hydro-pneumatic still open for consideration…..:ylsmoke:
As regards TAK-4 and Independent Suspension, I am playing devil’s advocate for the most part. I am still strongly inclined in the direction of Straight Axle. And you have convinced me that with coil springs + air suspension, Straight Axle can provide a really nice ride, especially in a 6x6. In fact, egn convinced me about this quite a while back. egn recounted a story about forgetting to put the gas-cap back on. He left it on a ledge on his vehicle, Blue Thunder; drove Blue Thunder about 100 km over some very rough terrain; and when he stopped, the gas-cap was still sitting where he left it.
Pretty much the only thing I have “concerns” about, regarding SA, is the turning radius. The G-wagen has a notoriously wretched turning radius because it’s SA. Oshkosh emphasizes the turning radius advantages of IS in the following video:
In the next few posts I will discuss the L-ATV a bit more, and post some more images. But don’t misunderstand my intent. I just wanted IS to get a bit more “air time”, before we decide 200 % against it.
Otherwise, many thanks for all the feedback: it is proving invaluable, and I certainly am learning a great deal. At least when the final project appears, nobody will be able to say that I paid insufficient attention to important engineering and overlanding basics, and that the resulting vehicle is wholly "unrealistic" or "impractical". Keep it coming!
All best wishes,
Biotect
Last edited:
biotect
Designer
..
************************************************
1. The Oshkosh L-ATV (Light Armored Tactical Vehicle)
************************************************
Hi all,
Here is another sequence of L-ATV "bounce" shots, demonstrating that the TAK-4i suspension, at least, never seems to allow the centerline clearance to droop below the wheel centers:
So what exactly is the L-ATV? Basically, it's Oshkosh's response to the JLTV procurement program.
And what is JLTV?
JLTV is the United States military program to replace the Humvee. Competitors have now been narrowed down to three: Oshkosh Defense, Lockheed Martin, and AM General (which built the Humvee). The excluded competitors were Navistar, BAE systems, and General Dynamics – see http://editorial.autos.msn.com/blogs/autosblogpost.aspx?post=ffb75760-7941-45fb-ad72-62038a0dbb48 , http://www.autonews.com/article/201...-in-$5-billion-effort-to-replace-aging-humvee , http://www.army-technology.com/feat...int-light-tactical-vehicle-competitors-1.html , http://defense-update.com/20120824_jltv_emd-2.html#.VBCUqnm9_6k , http://www.dodbuzz.com/2012/08/23/army-and-marine-corps-pick-jltv-winners/ , and http://www.freerepublic.com/focus/f-news/2923410/posts .
In 2013 each of the three successful "EMD"-phase winners delivered 22 test vehicles for intensive evaluation. Once testing of these 66 vehicles is completed in 2015, a winner will be announced. The production contract for nearly 55,000 vehicles will go to a single vendor, at a projected cost of 250,000 USD each, with the first vehicles delivered in 2018 – see http://defense-update.com/20111004_army-sets-jltv-target-price-around-250000.html#.VBCXKHm9_6k , http://defense-update.com/20130615_jltvs-revving-up-prior-to-final-test-phase-in-august.html#.VBCWGnm9_6k , http://www.army.mil/article/110066/Army__Marine_Corps_take_delivery_of_JLTVs_for_user_testing/ , http://www.army.mil/article/110710/JLTV_testing_begins__program_on_schedule__budget/ , and http://www.automoblog.net/2012/08/23/three-jltv-contend-for-us-military-humvee-replacement/ . So we are talking really big bucks here: 250,000 x 55,000 = 13,750,000,000, or roughly 14 billion dollars. Whoever wins the contract will be able to ride a gravy train for the next decade, at least.
For a very thorough, clear, and complete description of the JLTV competition process, see http://breakingdefense.com/2012/08/oshkosh-shows-off-jltv-contender/ . And if you are looking for a super-detailed, well-illustrated account of the JLTV program in 2012 (when there were still six competitors), and now in 2014, when there are just three, the “Light Armored Vehicles” compendiums on ISSU might be worth a look, and both are downloadable as PDF's – see http://issuu.com/vishmeh/docs/armada_-_oct_2012_compendium/7 and http://issuu.com/vishmeh/docs/compendium_light_armoured_vehicles_ .
************************************************
CONTINUED IN NEXT POST
.
************************************************
1. The Oshkosh L-ATV (Light Armored Tactical Vehicle)
************************************************
Hi all,
Here is another sequence of L-ATV "bounce" shots, demonstrating that the TAK-4i suspension, at least, never seems to allow the centerline clearance to droop below the wheel centers:
So what exactly is the L-ATV? Basically, it's Oshkosh's response to the JLTV procurement program.
And what is JLTV?
JLTV is the United States military program to replace the Humvee. Competitors have now been narrowed down to three: Oshkosh Defense, Lockheed Martin, and AM General (which built the Humvee). The excluded competitors were Navistar, BAE systems, and General Dynamics – see http://editorial.autos.msn.com/blogs/autosblogpost.aspx?post=ffb75760-7941-45fb-ad72-62038a0dbb48 , http://www.autonews.com/article/201...-in-$5-billion-effort-to-replace-aging-humvee , http://www.army-technology.com/feat...int-light-tactical-vehicle-competitors-1.html , http://defense-update.com/20120824_jltv_emd-2.html#.VBCUqnm9_6k , http://www.dodbuzz.com/2012/08/23/army-and-marine-corps-pick-jltv-winners/ , and http://www.freerepublic.com/focus/f-news/2923410/posts .
In 2013 each of the three successful "EMD"-phase winners delivered 22 test vehicles for intensive evaluation. Once testing of these 66 vehicles is completed in 2015, a winner will be announced. The production contract for nearly 55,000 vehicles will go to a single vendor, at a projected cost of 250,000 USD each, with the first vehicles delivered in 2018 – see http://defense-update.com/20111004_army-sets-jltv-target-price-around-250000.html#.VBCXKHm9_6k , http://defense-update.com/20130615_jltvs-revving-up-prior-to-final-test-phase-in-august.html#.VBCWGnm9_6k , http://www.army.mil/article/110066/Army__Marine_Corps_take_delivery_of_JLTVs_for_user_testing/ , http://www.army.mil/article/110710/JLTV_testing_begins__program_on_schedule__budget/ , and http://www.automoblog.net/2012/08/23/three-jltv-contend-for-us-military-humvee-replacement/ . So we are talking really big bucks here: 250,000 x 55,000 = 13,750,000,000, or roughly 14 billion dollars. Whoever wins the contract will be able to ride a gravy train for the next decade, at least.
For a very thorough, clear, and complete description of the JLTV competition process, see http://breakingdefense.com/2012/08/oshkosh-shows-off-jltv-contender/ . And if you are looking for a super-detailed, well-illustrated account of the JLTV program in 2012 (when there were still six competitors), and now in 2014, when there are just three, the “Light Armored Vehicles” compendiums on ISSU might be worth a look, and both are downloadable as PDF's – see http://issuu.com/vishmeh/docs/armada_-_oct_2012_compendium/7 and http://issuu.com/vishmeh/docs/compendium_light_armoured_vehicles_ .
************************************************
CONTINUED IN NEXT POST
.
Last edited:
biotect
Designer
CONTINUED FOM PREVIOUS POST
************************************************
2. JLTV Hybrid
************************************************
The JLTV program does not specifically require hybrid capability, but it is interesting that at least two of the current competitors (Oshkosh and Lockheed-Martin) have developed hybrid variants of their mechanical power trains. And these hybrid variants are serial or “2[SUP]nd[/SUP] generation” solutions. They are solutions in which there is no mechanical contact between the diesel engine and the axles.
Oshkosh seems to have a particularly deep and long-standing commitment to hybrid technology, and on its website suggests that alternative diesel-electric power-trains based on its “Propulse” technology are available now, including a hybrid power-train for the L-ATV – see http://en.wikipedia.org/wiki/Oshkosh_L-ATV , http://oshkoshdefense.com/products/light-tactical-vehicles/ , http://oshkoshdefense.com/vehicles/l-atv/ , http://oshkoshdefense.com/vehicles/jltv/ , http://oshkoshdefense.com/wp-content/uploads/2014/09/LATV_Global_6page_SnglPgs_LowRes.pdf , and http://oshkoshdefense.com/wp-content/uploads/2014/09/16589_JLTV_8pgBrch_v6_lowres_0904.pdf .
But notice how in its specifically JLTV literature, Oshkosh does not mention that the L-ATV has an alternative serial hybrid drive train. Whereas in its L-ATV literature labeled “Global” (i.e. presumably for export to other countries), a diesel-electric hybrid power train is most definitely an option:
It’s also worth noting that Oshkosh was not one of the three vendors chosen for the initial, TD or “technology development” phase of JLTV. Those contracts went to General Dynamics, BAE, and Lockheed Martin. And yet in the second “EMD” phase (engineering and manufacturing development) phase, the first two vendors were eliminated from the competition, and only Lockheed Martin was left standing. During the TD phase Oshkosh continued developing L-ATV technology at its own expense, but remained something of was an “insider”, because of its ongoing production of the M-ATV.
The M-ATV was a stop-gap "interim" solution that the U.S. military asked Oshkosh to develop, because HUMVEES and/or traditional larger trucks were proving simply inadequate in Afghanistan. The HUMVEE was too small and too lightly armored, while the bigger trucks were too slow and cumbersome. Something in the middle was required, hence the M-ATV. But the M-ATV was never intended as a permanent solution, but rather, as a temporary response to an immediate and pressing need. Still, the M-ATV is the vehicle in the current force that comes closest to the specification desired for the JLTV. Indeed, Oshkosh’s L-ATV is really a shortened and lightened verison of its M-ATV: about 1/3 smaller, it weighs about half as much, and it is 70 % faster cross-country – see see http://breakingdefense.com/2012/08/oshkosh-shows-off-jltv-contender/ .
For articles in the military and automotive press about the Oshkosh L-ATV, see http://www.armyrecognition.com/us_a...nical_data_sheet_specifications_pictures.html , http://www.army-guide.com/eng/product4658.html , http://defensenews-updates.blogspot.com/2012/03/dtn-news-defense-news-oshkosh-defense.html , http://www.thestreet.com/story/1147...grams-requirements-photo-oshkosh-defense.html , http://hybridabc.com/the-oshkosh-de...t-generation-performance-and-crew-protection/ , http://in.reuters.com/article/2012/03/27/idUS205308+27-Mar-2012+BW20120327 , http://marines.dodlive.mil/2012/04/04/the-l-atv/ , http://www.defensemedianetwork.com/stories/oshkosh-bids-l-atv-for-jltv-emd-phase/ , http://www.inautonews.com/say-what-...-humvee-with-diesel-hybrid-l-atv#.VBCHinm9_6k , http://www.gizmag.com/l-atv-humvee-replacement/19851/ , http://www.armyrecognition.com/octo...ufacturing_and_development_phase_2210121.html , http://www.armyrecognition.com/ausa...all-terrain_tactical_vehicle_ausa_261013.html , http://www.armyrecognition.com/dsei...or_the_first_time_in_europe_at_dsei_2013.html , http://www.armyrecognition.com/idex...international_debut_at_idex_2013_0901135.html , http://www.businesswire.com/news/home/20130614005051/en/Oshkosh-Defense-Demonstrates-JLTV-Prototypes-U.S.-Department#.VBCRbHm9_6k , http://defense-update.com/20110914_latv.html#.VBCUsnm9_6k , http://www.msport1.net/Other_Right_Oshkosh Defense at CANSEC 2013.html , and http://www.army-technology.com/proj...ght-combat-tactical-all-terrain-vehicle1.html .
Hope that answers most questions thread participants might have about the L-ATV and the M-ATV, and the relationships between the two.
What now follows is my collection of L-ATV "still" images. Not quite as illustrative as the moving video screen captures posted earlier, but perhaps still useful for understanding TAK-4i independent suspension:
************************************************
CONTINUED IN NEXT POST
.
Last edited:
biotect
Designer
CONTINUED FOM PREVIOUS POST
************************************************
Here are some more videos of the L-ATV:
[video=vimeo;50167695]http://vimeo.com/50167695 [/video] [video=vimeo;104752753]http://vimeo.com/104752753 [/video]
[video=youtube;Yqp67Pd55wM]https://www.youtube.com/watch?v=Yqp67Pd55wM [/video]
[video=youtube;ddW56E6IUSU]https://www.youtube.com/watch?v=ddW56E6IUSU [/video] [video=youtube;eBG7Ytd8tMo]https://www.youtube.com/watch?v=eBG7Ytd8tMo [/video]
[video=youtube;5fykzW_BIVw]https://www.youtube.com/watch?v=5fykzW_BIVw [/video]
For two additional videos which I can't embed, see http://www.military.com/video/comba...nt-light-tactical-vehicle-demo/1799616176001/ or http://defensetech.org/2012/08/23/oshkosh-showcases-jltv-entry-l-atv/ , and http://www.military.com/video/comba...ers/oshkosh-defense-l-atv-jltv/1543754676001/ .
All best wishes,
Biotect
Last edited:
biotect
Designer
IS:
Looking good - BUT still there is more obstacle-catching stuff underneath than on a SA.
In these pictures the IS system is not at too steep an angle - BUT also doesn't have ground clearance any better than SA.
Here the rig is probably 1/2 in the air and the suspension is drooping fully - steep suspension angles - on "touch down" it will force the tires laterally to the outside.
Doesn't matter on this terrain - matters a LOT if you are slow in rocky terrain - to the point where the tires actually can lock up the suspension agaist a rock face....
And what is the most deciding factor for me is - going slow, when only one wheel rises the center of the vehicle stays low for a long part of the wheel travel, before it starts to lift the body. Part of the intend of IS is exactly that feature - keep the CAR-(body) as undisturbed by road imperfections as possible - let wheel ride over it and return to the normal level.
Great for cars and in Rally like applications, where you hardly ever encounter actual obstacles taller than the ground-clearance.
In areas where you need to clear SERIOUS obstacles (where Rally speeds would destroy everything....) at slow speed - the IS-forte becomes detrimental....
Absolutely good and valid point FOR IS! This is why you bring along SOME toy to explore where you cannot/wantnot go with the big rig.
However, I believe the Spec wishlist for Terraliner want's to go further in to "terrain" than you are willing to risk your ride....
For me personally - after seeing the Rally rigs "fly" with SA - I think I would stick with SA for their simplicity and rather get more sophistication into the springing and damping - still way less link/joint count...
[Any Full Size Truck IS I saw so far is essentially double wishbone layout - LOTS of joints....]
ANYTHING that shows the TAK-4 suspension has the suspension-arms essentially straight out - level with the ground (but for a very shallow angle)
A it is - SA WILL have better ground clearance compared to the TAK-4.
Ridequality better than SA - ...WHAT are we comparing??
I don't see any TAK-4 equipped vehicle leaving the ground - so ride-comfort doesn NOT depend on unsprung weight, but only on proper springing/damping.
The TAK-4 lite is about the same as the original Humvee - propably with better geometry and springing/damping - gives a way better ride, but doesn not improve off-road prowess at all!
Remember - these guys are in the business to make money - and will promote their product at any price!!
To investigate and compare is up to the customer!
[Note, that they do not claim any better ground clearance or off-road ability - they really just claim a better ride, which is great if that is what they need! HOWEVER SA equipped vehicles could just as easy be improved on the ride quality! Military is big business and corruption - ....]
thjakits,
I did not expect you to be familiar with the latest incarnation of TAK-4, i.e. TAK-4i as implemented in the L-ATV. But I think you will have to agree that even in very "neutral" images where there is no bounce, TAK-4i provides better center-line ground clearance than Straight Axle:
Also watch the L-ATV videos that I just posted above. The pronounced "V-shape" of the undercarriage is self-evident throughout, and seems to be the natural, at-rest position of the suspension. The suspension only goes as flat as a straight axle after a "bounce". And even in the most extreme moment of a down cycle, TAK-4i still as good as Straight Axle:
Of course, some images do exaggerate because they depict the vehicle flying, and the wheels drooping:
Your point about touch-down forcing the tires to the side is well-taken. But when driving slowly on rocky terrain, presumably one will never be "flying" in any case. So there's no "touch down". So perhaps one should not worry too much about lateral movement of the tires locking the suspension against a rock face? This is an honest question, because I have no experience driving IS slowly over rocky terrain. It's clear that driving Single Axle slowly over rocky terrain won't do this. But is this a real, genuine problem for IS driven slowly over rocky terrain?
If it were a genuine, real problem, then how is it that the TerraMax MTVR with TAK-4 independent suspension, depicted in the following video, would seem to be able to negotiate rocky terrain slowly quite well:
************************************************
CONTINUED IN NEXT POST
.
Last edited:
biotect
Designer
CONTINUED FOM PREVIOUS POST
************************************************
The only thing that I might be willing to concede, is that when the L-ATV corners, maybe (but only maybe) the inside wheel's center drops below the vehicle's center-line, in a manner that might be worse than straight axle:
But this is not clear, as the following images of the M-ATV suggest:
These two images suggest that the most recent versions of TAK-4 have an "up travel" limit: that the inside tire when turning can only travel upwards to the limit where the suspension is as straight as a straight axle. So the concern that you express in the following sentence seems misplaced, at least as far as TAK-4 is concerned:
But needless to say, I am no expert, and here I am simply playing "devil's advocate". I am trying to keep IS in play a bit longer, so that it is not prematurely dismissed out of hand. NeverEnough, campo, and dwh are all enthusiasts for some kind of Independent Suspension, so this alone inclines me to want to take IS seriously. And both NeverEnough and campo are serious explorers with big rigs. I appreciate your passion for SA, and for me this spirited debate has tremendous value, because I am learning a great deal about the pros/cons of IS versus SA, with respect to the TerraLiner specifically.
All best wishes,
Biotect
Last edited:
...BACK to a Portal Axle and I have MORE ground clearance and all off the slow/rough benefits of the SA.
For the speeds you want to go in the Terraliner in "Rally Mode" - you should concentrate on Air-Suspension or Kinetic-style...
Forget even Coil-Springs they are still only perfect in ONE specific load configuration..... (...not to mention leaf-springs, although leaf-springs are just as good as Coils - but also at ONE load configuration only).
Watch it, mate!! As soon as you start to space out the tandem you get into serious tire murder territory - unless you use at least 1 steered axle in the back!!
I already posted/argued that one!!
A closely spaced tandem is already bad enough.....
The Tanami is an extreme example. Commercial Trucks are on time-line. MOST commercial trucks are NOT specifically built for the Tanami, rather adapted from less than optimal base lines. I would say a Tanami specialized Truck would be fine after all - IS or SA....
YOU don't HAVE to run with the big guys - take it easy!
ON another note - running the Tanami with a proper suspension at 100km/h (if you dare to get there!!) will probably be "softer" on a hub-motor even with the larger suspension movements, .... than the short but hard shocks a hub motor will receive from a 250km/h sportscar on even small iregularities on a rough road track!!
You won't believe how rough a track becomes at speed and also how rough it is to ride at speed - ask the formula guys!
Suspension is adjusted to keep the bloody thing on the track - NOT for driver comfort (for the driver there is essentially no spring/damper beyond the 1/2"-foam in the seat....)
If a hub-motor can survive that, it should survive a Tanami - occasionally (you will not do Tanami's everyday - ....like some of the truckers in the videos...)
Though I did/do favor the central motor configuration - I am getting very partial to a possible central motor for the rear MAIN drive and hub-motors for the 2 front axles - at the end it will also depend a LOT on things I have NO clue how to figure out: efficiencies, regen-braking capabilities/efficiencies, hub motor weight (for the 3rd time - I do NOT like the "In Wheel"-pancakes. I DO like the Grimsel Racer like smaller, VERY light, geared motors!).
Hub motors will let you have DIRECT access to torque steer and stability control. Central Motor via SA (or IS and drive shafts) have to control indirectly via brake application....
Correct - suspension type and e-motor type are 2 different items on the list - either one is good for either one.
HOWEVER: One advantage you CAN get from a IS is with HUB-MOTORS!! THis configuration will keep a big space in the center clear - where you would have your 3 cetral e-motors and to a lesser amount the SA (...with hub-motors these will be rather small, but still go laterally through the center)
Bio! WHATEVER YOU WANT!! YOU need to decide what you want Terraliner to be capable of!!
As I just mentioned above - there is at least one configuration, where IS will give you a serious advantage over SA!
However at the end YOU need to decide if this specific advantage is worth it to you to lose the superior slow/offroad prowess of the SA over the IS!
At some point you were ADAMANT about equal axle spacing to reduce break-over angle! This showed, that you would like Terraliner to be able to do some serious crawling with some serious articulation and based on this we all tried ot make our point for one or the other configuration!
NOW you decided that equal spacing is NOT a must anymore (....and I agree, as posted before - but I think my suggested layout has an advantage over the 1 front 2 rear layout - you can reduce that advantage by adding 1 rear steer axle to mitigate the limitations of a straight tandem, but I believe my suggestion still would be better, IF you keep insisting in serious OFF-road capability - even though we stay on roads, bad ones at that.... - need to think about this one some more - ... doing trials right now in my brain!!)
Look - it might look like I am all SA and damn IS - NOT TRUE - it all depends WHAT DO YOU WANT/NEED/REQUIRE?!!
Somewhere there is a switchover point where IS will have more advantages overall. But until recently your Terraliner spec/requirments where solidly in SA territory (...at least the way I understood the requirements).
You also need to always take in account the springing/damping systems you will want to employ - when you compare suspension systems!
Look at Rally trucks - ALL doing the same and ALL work - loads of different systems! Their ride-QUALITY (for driver and co-pilot) though will be secondary - safe HIGH SPEED for the race-unit will be primary!
So - already diverging from the Terraliner requirements!
Hell, you even could use LEAF-springs to locate the SA and then run Air-Suspension on top!! [Leafs rated to the lowest weight possible - so take a base load and locate the axles - then you adjust added load and ride height with air-bags on top!!]
...or (if you adopt my latest layout) a SA-rear main drive with a central motor and 2 front steering axles with IS and hub motors - don't see any reason or advantage for that layout - but hey, you call the shots and at the end you have to justify to yourself WHY and WHAT....
Bio - you can change specs everyday and most of us will have an idea for a BEST solution for that specific spec, no problem.
But sooner than later you need to freeze at least the requirements for terrain/obstacle prowess!!
- DO you want to give the owner the capability to go all out and do crazy things? (...even if they never will use that capability....)
- DO you want to limit the owner to rough, but less challenging roads by default? (If you make Terraliner IS, automatically the obstacles you still can challenge are smaller than with a SA - so, the point where progress will stop will be less rough, than when you use SA. ONE way to avoid that Terraliner gets into the news because of over confidence or lack of experience or lack of ability....)
The point where I would most likely changer to IS though is very close to where a regular bus can go too!
I think we agreed on, that a Highway top-speed of 120 km/h is more than enough (...besides that you most likely will be actively restricted to 100km/h (105) or even 80km/h (85) by legal requirements in Europe - depends how you get the thing certified - IF legislation insists that this is a truck you get nailed at 80/85....
Considering the top speeds Rally Trucks reach on rough terrain (guessing some 140-160 km/h.....and with SA) - I believe, there is not much reason to give up slow/offroad/obstacle capability for a subjectively better ride with IS at "higher speeds" - by now, the only reason why I would go IS (...if I can be convinced to forefeit "rock crawling" abilities), is with hub motors for the substantial space gain in the center of the truck (...gone out the window with 3 motors in the center...)
So - BIO - the question how much ground clearance Terraliner should have is NOT answerable until we know WHAT/HOW MUCH do you want Terraliner to be able to do in the very slow, very rough terrain
OR
in other words: HOW rough and bad do you want to be able to go??
thjakits
Last edited:
NeverEnough,
...did you have your front suspension adjusted to your needs?
The description you gave:
...sounds like you adapted a Dump Truck Chassis to your needs - your troubles might be because of too much spring up front..??
With experience like that it would be easy to hope for a better ride from IS [...at the end IS also needs the correct springing/damping or the ride will be just as miserable]
IF you would convert to Air-Suspension up front - I bet the story would change drastically!!
[I believe a Air-Spring conversion might be even cheaper than a Leaf-spring change..... or a combination - as mentioned earlier - a soft leaf to locate the axle and provide a base load and then air-bags on top for more load! NOT really "Helper Air-Springs"!! The suggested configuration would be decidely soft - just enough to locate the axle and take the minimum operating load: near empty fluid tanks, no supplies, no equipment, one driver, no pax - basically the lightest configuration ever you possibly could encounter yourself with...]
thjakits
...did you have your front suspension adjusted to your needs?
The description you gave:
...sounds like you adapted a Dump Truck Chassis to your needs - your troubles might be because of too much spring up front..??
With experience like that it would be easy to hope for a better ride from IS [...at the end IS also needs the correct springing/damping or the ride will be just as miserable]
IF you would convert to Air-Suspension up front - I bet the story would change drastically!!
[I believe a Air-Spring conversion might be even cheaper than a Leaf-spring change..... or a combination - as mentioned earlier - a soft leaf to locate the axle and provide a base load and then air-bags on top for more load! NOT really "Helper Air-Springs"!! The suggested configuration would be decidely soft - just enough to locate the axle and take the minimum operating load: near empty fluid tanks, no supplies, no equipment, one driver, no pax - basically the lightest configuration ever you possibly could encounter yourself with...]
thjakits