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tracks.. vs.. Tires... I would vote tracks... If... the desired land speed was slow.. specialized RUBBER or synthetic tires for higher speed transport. Solid Axles. etc.. using items from the offroad Rockcrawling industry. With the Martian G being what it is, I think that many of the advantages of Tracks will be less noticed. You will be put less weight on a given foot print, Keep it simple.. As far as micron sized dust particles.. They will be an issue that Sharper image can't solve. I think the only way to truely pull these out of the air is through a water air filtration system or something of that nature. If someone wants to goto mars.. they will take the risk...
We are only limited by our Will and our Imagination.
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Back near the beginning of this thread, Rik made a suggestion about a possible design for a wheel which would function well in Martian conditions.
It looks like somebody from Michelin was lurking in the background and has quietly lifted Rik's idea! ??? :;):
Have a look at http://www.gizmo.com.au/go/3603/]this article.
I'm not sure whether it's relevant to this discussion because I don't know how well the flexible spokes of the wheel would stand up to extreme cold. We may have the same problem that we had with traditional rubber and even metal mesh(?).
But, judging from the way the prototype (called a 'TWEEL' - integrated Tyre/Wheel) performed on an Audi recently, we may be seeing these things on standard road-going vehicles before long.
You should have taken out a patent, Rik!
The word 'aerobics' came about when the gym instructors got together and said: If we're going to charge $10 an hour, we can't call it Jumping Up and Down. - Rita Rudner
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Interesting desing, i wonder if you could place some sort of energy making device on the spokes. Im thinking of the consept that i saw some were that used larg flotes on the ocean to move pumps that some how made electricity, forgive me late at night cant remember the artical well. but i wonder if you could place a liquid (one that wont freeze of course) or maby use a piston method to make power to help propel the veical?
also a plug for tires that i bet has been said (only read the first 3 pages) they are more versital, as in you can plase them jsut about any were on the body of the veical.
I am an amateur at best.
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Back near the beginning of this thread, Rik made a suggestion about a possible design for a wheel which would function well in Martian conditions.
It looks like somebody from Michelin was lurking in the background and has quietly lifted Rik's idea! ??? :;):
I'm rich! Beter call my lawyer!
*reads article...* Nice design... But not exactly what I had in mind, sigh... So no money for me, heehee...
Good question about extreme temperature performance... Hope some space-car people have a hard look at this one...
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The is better used being stored elastically in the spokes than being recovered.
The will definitley need to be some sort of paved area out side the airlock that can be blasted down daily. Cleaning outside before entering an airlock that is being kept at positive pressure should cut down on the amount of dust getting in the qirlock significantly right?
On tracks vs. wheels, efficiency is top of the agenda due to the premium on power/fuel.
Could a mesh tire have ...thin plutonium wire?... woven through it or small amounts of something warm alloyed with it? Plutonium pellets keep the rovers happy...
Come on to the Future
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The will definitley need to be some sort of paved area out side the airlock that can be blasted down daily. Cleaning outside before entering an airlock that is being kept at positive pressure should cut down on the amount of dust getting in the qirlock significantly right?
I'm not sure if needs to be "paved" but you are right finding somemethod of dust managment is likely to be key. In a diffrent topic we briefly talked about some sort of CO2 "air curtian" being utilised to help create a dust free zone where the dust can more easily be removed via air-pick or something. Something on a larger scale will probably eventualy be necessary to help facilitate vehicle maintence.
Could a mesh tire have ...thin plutonium wire?... woven through it or small amounts of something warm alloyed with it? Plutonium pellets keep the rovers happy...
While I am actualy all in favor of using radiactive elements as heat sources, plutonium wire is a little bit of over kill. If rubber tires need to be heated, electrical current will probably be sufficent.
He who refuses to do arithmetic is doomed to talk nonsense.
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Radioactive elements can't breakdown as such. Well not for a few hundred years.
As far as paving goes... the surface needs to be sealed for a generous distance if your spray down is going to be effective or you will be trying to clean yourself in a dustbowl.
Come on to the Future
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This article works though the calculations for use on the moon of a solar powered lunar buggy or rover.
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On a future Martian colony, which do you think would be more likely to be used on ground transportation vehicles; tires or tracks-or some other method of moving along the ground?
Personally, I favor tracks as they require no synthetic rubber and no material to inflate them. Which do you think would be most practical?
How about a big long Cylinder habitat with a pair of wheels about it's circumference (one at each end) so it is a two wheel drive mobile habitat...
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Legs. Six of them. The lowly roach isn't a bad basic design for an all-terrain vehicle.
Build a man a fire and he's warm for a day. Set a man on fire and he's warm for the rest of his life.
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Legs. Six of them. The lowly roach isn't a bad basic design for an all-terrain vehicle.
*You mean http://www.newmars.com/forums/viewtopic … ]something along these lines?
Dang, it took me quite a Search to find this old thread (old?? I didn't recall it being from just this year...). Fortunately I recalled that John Deere manufactured it (after then scrolling through many pages of the Science & Technology folder); Searching with JD brought it up.
I also scrolled through this thread to see if the article had been posted previously here; it hasn't.
--Cindy
We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...
--John Sladek (The New Apocrypha)
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Legs. Six of them. The lowly roach isn't a bad basic design for an all-terrain vehicle.
*You mean http://www.newmars.com/forums/viewtopic … ]something along these lines?
Dang, it took me quite a Search to find this old thread (old?? I didn't recall it being from just this year...). Fortunately I recalled that John Deere manufactured it (after then scrolling through many pages of the Science & Technology folder); Searching with JD brought it up.
I also scrolled through this thread to see if the article had been posted previously here; it hasn't.
--Cindy
Two click from Cindy's link is this. http://www.defensetech.org/archives/001434.html]MP3 players for your AK-47 - - just what every insurgent needs for Christmas, oops, whatever holiday insurgents celebrate.
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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Not many places for solar panels, oups I mean for the cindy's link.
The fact that it is human operated and has a dome for the cab could lend its self to being used on moon or mars. Next problem is the power source to run it.
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Can I get one for my SKS? how about my M-44 Carbine?
Probably not.. oh well..
We are only limited by our Will and our Imagination.
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It looks like we have a combo tire track design that will e the winner in the Marscart topic....
and another topic to fix....
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Finally fixed topics artifacts and shifting that I flagged awhile ago.
With the rovers current wheel design still taking a pounding and there being no words from Nasa of a change to its design to resolve its longevity of use the topics core element is still a valid question as any vehicle we use for man will be much heavier and would see more damage at the same speeds with the materials and design selection currently in use.
This sounds more like a college level challenge to look at the other options for moving on mars and how to fix the issues.
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I think for the early colony, making cogs and tracks will be easier than anything else. So I would support tracks for initial ISRU vehicle design on Mars. Using electric motors will make for simple engines. Mnaufacturing of basic vehicles e.g. for transport between habs at the base could be achieved within 5-10 years if we import to Mars the right machines.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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Wheels are for use on roads. Tracks are for use off roads. The US Army has conducted a slew of studies on this topic and that was their conclusion after exhaustively researching this topic over the course of multiple decades. Every time they propose a new wheeled APC that's supposed to be a replacement for a tracked APC, they conduct another study and determine the same thing. Basic physics will not change to favor boys who like trucks because they played with trucks as kids. Trucks work great on roads and I own a Silverado, so I'm no different in my love of trucks, but you'll never see me suggest that it's as durable or capable as a tracked vehicle of equivalent weight and power for pure off road usage. I can't make it overcome physics. It'll never make a good airplane, either.
If Mars had any roads, I would be here advocating for the use of wheeled vehicles. Unfortunately, it does not. Even after trails are graded using tracked vehicles with blades attached, the physics involved still does not favor the use of wheels unless the regolith is compacted. After bases are established and compacted regolith is used to construct thoroughfares between modules or bases there, then and only then should wheels be used in preference to tracks.
If we ever needed to deliver mass quantities of raw materials between two places on Mars separated by any significant distance, then we need railways for that purpose. That's just more basic physics.
The wheels on the rovers we've sent there work acceptably well because the rovers are lightweight and move at a snail's pace.
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Kbd512 is quite right. Where there are real roads, wheels work better. Where there are not real roads, tracks are the better choice. -- GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Depends on the amount of snow/slush you get in your area. I have tracks on my sxs and when the slush gets deep during a warm up or when the drifts start to stack up along the shoreline they are worth their weight in gold. That being said, an ATV with chains on the rear tires can be pretty capable also.
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Early metals manufacturing activities on Mars should attempt to make Nickel-Iron battery plates along with forging tools and track links for repair of light tracked vehicles. Sturdy vehicles are required to go places and collect things, so some effort should be made to produce the wear parts locally and the parts are small enough that massive machines are not required. The chassis, electric motors, and Lithium-ion batteries require far less frequent replacement and are complicated to produce, but don't weigh that much compared to steel parts and base energy storage. Locally manufactured Nickel-Iron batteries may become the stationary energy storage medium of choice because they're simple to make, last an acceptable number of cycles, and have fewer issues with the cold than Lead-acid or Lithium-ion, reconditioning is possible, and they won't need to be imported from Earth in the way that Lithium-ion batteries will.
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Not true. Depends on the terrain. Tracks work well in mud or firm sandy deserts. But not in boulder terrain.
From Wikipedia:
"A tank can travel at approximately 40 kilometres per hour (25 mph) across flat terrain and up to 70 kilometres per hour (43 mph) on roads, but due to the mechanical strain this places on the vehicle and the logistical strain on fuel delivery and tank maintenance, these must be considered "burst" speeds that invite mechanical failure of engine and transmission systems. Consequently, wheeled tank transporters and rail infrastructure is used wherever possible for long-distance tank transport. The limitations of long-range tank mobility can be viewed in sharp contrast to that of wheeled armoured fighting vehicles. "
The fact that even a metalled road "invites mechanical failure" shows that tank tracks would not perform well in boulder terrain.
Kbd512 is quite right. Where there are real roads, wheels work better. Where there are not real roads, tracks are the better choice. -- GW
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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My experience in the U.S. Army was spent watching soldiers continually working on tracked APCs (armored personnel carriers), which had an alarming breakdown rate. Tracked vehicles are inherently maintenance intensive vehicles when compared to wheels. This is why I've always supported the concept of a 6 WD rover with computer controlled independent wheel drive system. When combined with a winch and long cable system and a man portable screw-in point of attachment makes wheels entirely viable for most applications.
Online
Tanks vs Cars comparison chart
AFV/tank tracks can be divided into three broad categories:
Belt (also known as Rubber Band, or Flexible)
Link and Length (also known as Assembly type)
Individual Link (both working and non-working)
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Not true. Depends on the terrain. Tracks work well in mud or firm sandy deserts. But not in boulder terrain.
From Wikipedia:
"A tank can travel at approximately 40 kilometres per hour (25 mph) across flat terrain and up to 70 kilometres per hour (43 mph) on roads, but due to the mechanical strain this places on the vehicle and the logistical strain on fuel delivery and tank maintenance, these must be considered "burst" speeds that invite mechanical failure of engine and transmission systems. Consequently, wheeled tank transporters and rail infrastructure is used wherever possible for long-distance tank transport. The limitations of long-range tank mobility can be viewed in sharp contrast to that of wheeled armoured fighting vehicles. "
The fact that even a metalled road "invites mechanical failure" shows that tank tracks would not perform well in boulder terrain.
Nobody who doesn't want to break a track or an axle drives over boulders if they can avoid them. We don't drive the Mars rovers over sharp rocks precisely because it messes up the wheels. It's a dumb idea in any type of vehicle. The higher the CG is and the bigger the boulder becomes, the dumber the idea becomes. Vehicles with dozer blades can actually push boulders out of the way and the military does that when they have to.
Wheeled transporters and railways are used because there are these things called "roads" and "railways" here on Earth and all armored vehicle are heavy and consequently burn a lot of gas as a result. We also transport Strykers by railway, even though they have 6 wheels, for the exact same reason. There are no roads or railways known to exist on Mars, unless the aliens have been holding up murals in front of the rover cameras to fool stupid humans.
Strykers have 6 tires that cost $6K per copy. An AK47 can put a hole in any of them, from any angle, at 300m or less. A PKM or SVD can double that engagement range, put a hole through both sides of the tire, and render the Stryker completely immobile in seconds. We know this because it has happened in combat... repeatedly... fighting illiterate camel herders... rather than slightly better educated and more disciplined Russians. The ground pressure is so high that the Stryker can't afford to lose any tire pressurization in any of its 6 tires, which is why it comes with an inflation system you can operate inside the vehicle.
The M113 can take hits from any of those weapons all day long from any direction and it certainly won't do anything at all to the vehicle's forged steel track links. The M113 weighs less, is a smaller target even though it still provides greater total volume under armor, and it actually fits into a C-130 without disassembly. The M113's cost $275K and the Stryker cost $4M. Upgrading the Australian M113's cost some $2.32M per vehicle. If you put rubber band tracks on the M113, then it's every bit as fast as the Stryker on a road and faster off road. In practice, the Strykers are speed limited on the poor quality roads in third world countries due to issues with rollovers and road collapses from the weight of the vehicle. The Strykers' suspensions have had serious issues in Afghanistan, but they're still better than HMMWV's unless cost is any sort of consideration.
The dude who thought a 105mm gun on a vehicle with a high CG to begin with, like the Stryker, was a good idea needed to lay off the crack pipe. It wasn't even a good idea on the much lower CG M113. The Russians have mostly switched to 30mm automatic cannons because, well, large caliber heavy recoiling weapons on light armored vehicles was never a particularly good combination for long term durability.
"I thought it was bad being in a submarine, but this is really horrible." - Admiral William J. Crowe, USN, after being inside a LAV-25
He's obviously never ridden in a M113 or he'd have a better opinion of the LAV series of vehicles.
In any event, if I was on a road or about to roll over an IED, I'd rather be in a Stryker because flat bottomed hulls and IED's are a terrible combination. If I was off road or about to get shot at, I'd rather be in a M113 because deflated tires mean I'm not going anywhere and if any of those yahoos have RPG's or mortars, it could be a really bad day.
Everything is a trade off. The fact that wheeled vehicles can be made to work off road does not mean they work well.
Oldfart1939,
After they up-armored the HMMWV and started adding crap to the already heavy Stryker / LAV series of vehicles, they became far less mobile than the original versions were. The tracks for the M113 have also been greatly improved over the years. The metallurgy and design life of the tracks is much better than the originals were. There are also rubber band tracks available as substitutes for linked tracks.
If you break an axle or pop a tire, you're not going anywhere for very long unless you have a replacement. If you break a track, there's this little technique called short tracking. It's how many a tracked vehicle has made it back to base.
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