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Vehicle locomotion methods


kristof65
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In the process of a personal project, I've been doing some speculation on future ground vehicles, and some questions have popped up that I think are ripe for discussion and speculation.

 

First off, I can think of five different methods of locomotion:

 

- Legged/walker

- Wheeled

- Tracked

- Hover (whether air cushion or grav vehicle)

- Sled/Skis

 

Everything I can think of for ground vehicles falls into one or more of those categories. Not missing any, am I?

 

Beyond that, I'm interested in alternative technologies for wheels and tracks, and some of the drawbacks/advantages of each.

 

On wheeled vehicles, we're mostly used to a metal rim with a rubber tire. But there other technologies in use - IE, IIRC, NASA used a steel mesh for the tires of the moon rovers.

 

 

Tracks - whether they're on robots, bulldozers or tanks, it seems that there are pretty much only two types of tracks - rubber tread type or matal ones made of heavy chain like links. For tanks especially, the heavy individual links are dominant. Over the decades, this is obviously tried and true, but our advancing technology seems like it would offer the potential of different technlogies. But what might those be? One thing that comes to mind is the possibility of something like a titanium mesh that operates more like a rubber tread than the big heavy tracks we have now.

 

Thoughts?

 

 

 

 

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You could mix them. I can see a car with four legs with fat wheels on the ends. It can roll like the wind down a road, but also step through rubble piles or stacks of dead zombies. Jump jets for brief hops over obstacles. Spiked arms that dig in ahead and drag the main vehicle along behind it. That's very clunky, but might work for you. Short range teleportation.

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I suppose I should explain what I'm doing here - I'm modelling a couple vehicles for myself for use with the NOVA minis.

 

I can see a car with four legs with fat wheels on the ends.

One of the vehicles I'm working on is a wheeled light tank. The wheels themselves aren't on legs, but are on cross arms that can adjust the ride height of the vehicle to allow for a low profile as well as quick travel on roads, but more than capable enough on rough terrain. I'm thinking the wheels themselves will be more akin to the metal wheels of the moon rovers, than traditional tires.

 

One of the other vehicles I'm comptemplating is a heavier tank, but the tracks are on legs as you mention.

 

I'm thinking about various alternatives simply because they might inspire other ideas for tanks and APCs.

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First off, I can think of five different methods of locomotion:

 

- Legged/walker

- Wheeled

- Tracked

- Hover (whether air cushion or grav vehicle)

- Sled/Skis

 

Everything I can think of for ground vehicles falls into one or more of those categories. Not missing any, am I?

 

I had a toy as a kid that combined:

- Legged

- Wheeled

- Sled/Skis

 

Given Warwick's comment you might consider adding:

- Combination

 

The WWII 'half-track' is the classic example.

 

I guess Mag/Lev trains fit under the hover category and normal railroads would be wheeled. If the Venusians, LGMs, or Froggy the Great created a mecha-noid thing that replicated the motion of a snake (particularly a sidewinder rattlesnake) what category would that go in?

 

Some implementations of hover are really aircraft and not ground craft.

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The snake would be some sort of friction drive, I guess.

 

On a less serious thought, but still along the lines of friction...Rocket Sled. No subtlety, not a lot of steering, mostly just point, ignite and GO!!! Good for Mad Max -ish, post-apocalyptic insanity. Might work on smooth water and short range ballistic launches. Unfortunately, this method of locomotion implies a one-way trip with a high rate of driver/pilot mortality, but still, if you need some comic relief...

 

Or not. :unsure::huh:

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Very Cool.

http://static.howstuffworks.com/gif/hyanide-1.jpg

 

While Legged/Walker vehicles are cool in Sci Fi, even if we got them to work I doubt they'd ever be used for warfare. Just too heavy maintenance, fragile, and a tall silhouette.

Hover has the disadvantage of slaloming due to light weight and lack of traction (think hydroplaning times 100), dangerous in very rough weather, loud as heck. although I imagine the last two could be fixed in a futuristic method the first would mean that it realistically could never be used in direct warfare as the larger shells hitting it would ruin it's stability, as would larger weapons mounted to the vehicle.

 

Realistically, we used wheeled and tracked vehicles for one purpose, they're the best thing for warfare. They provide stability, speed, and can bear more weight.

I'd look more at armor angles and weapons configurations than trying to reinvent the wheel.

Look at APC's, or the Ferret.

http://www.tomtownsend-toyland.com/toyland/IMG_0446.jpg

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While Legged/Walker vehicles are cool in Sci Fi, even if we got them to work I doubt they'd ever be used for warfare. Just too heavy maintenance, fragile, and a tall silhouette.

I agree completely, and it's one of the problems I have with games like Battletech and CAV. Big stompy robot vehicles look cool, they just aren't practical with known or projected technologies.

 

I'd look more at armor angles and weapons configurations than trying to reinvent the wheel.

Look at APC's, or the Ferret.

http://www.tomtownse...nd/IMG_0446.jpg

One of the the things about the Ferret, the Humvee and other wheeled APCs is that the tire is a vulnerability. That kind of limits the vehicle configurations. I have an idea for a cool looking wheeled light tank, but like big stompy robot tech, it's not viable (under todays current technology) because of the wheel/tire vulnerability. However, if the nature of the tire/wheel can realistically be changed to something more durable, etc, it makes the idea all the more plausible - and that's what I'm really searching for here.

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While Legged/Walker vehicles are cool in Sci Fi, even if we got them to work I doubt they'd ever be used for warfare. Just too heavy maintenance, fragile, and a tall silhouette.

I agree completely, and it's one of the problems I have with games like Battletech and CAV. Big stompy robot vehicles look cool, they just aren't practical with known or projected technologies.

 

I'd look more at armor angles and weapons configurations than trying to reinvent the wheel.

Look at APC's, or the Ferret.

http://www.tomtownse...nd/IMG_0446.jpg

One of the the things about the Ferret, the Humvee and other wheeled APCs is that the tire is a vulnerability. That kind of limits the vehicle configurations. I have an idea for a cool looking wheeled light tank, but like big stompy robot tech, it's not viable (under todays current technology) because of the wheel/tire vulnerability. However, if the nature of the tire/wheel can realistically be changed to something more durable, etc, it makes the idea all the more plausible - and that's what I'm really searching for here.

A big circular metal plate that extends past the wheel well and covers all but 2 inches of tread.

Basically a huge Hubcap.

Kinda like the APC from Aliens:

Aliens_APC_P1000771b.jpg

 

Also this:

1.jpg

 

 

Theoretically, you could use steel tires, you just wouldn't get a good grip and you'd need some killer shocks.

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I agree with kristof. I think walkers look cool, but I don't see them as being viable. A smaller sized one, like the forklift/walker from the Aliens movie, with the right armor, would make an infantry man into some sort of tank that could enter buildings and stop small arms fire.

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At the end of the movie "I Robot" (Will Smith flick, loosely based on an Asimov novel) the US Army shows up and restores order. And they (being no fools) have tanks or APCs with honest-to-God human drivers and gunners (I guess robots were insufficiently trustworthy for Mil-Spec equipment—or the Three Laws of Robotics precluded military applications :unsure: ). The important point for this discussion is the vehicles had neither treads nor wheels. They had spheres at the corners, embedded into the armored-skirt, and it looked like the sphere could roll any direction. It was like casters but without axles or pivots.

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I agree with kristof. I think walkers look cool, but I don't see them as being viable.

 

Yeah, Main Battle Tanks very seldom have to make piloting rolls to keep from falling over*. And a Rheinmetall 120mm smoothbore, (like Bored Flak, Mighty Bolt Lobber**), seldom misses at this*** range.

 

 

 

* "Colonel, I regret to report that I've fallen and I can't get up."

 

** Someplace or other I have a Bored Flak**** crosshair ring. IIRC, it was made by RPP*****.

 

*** For values of "this" less than 3000m.

 

**** If this means nothing to you, you're probably not nearly as old as dirt. I am nearly as old as dirt.

 

***** Ral Partha, of course.

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I would say it depends on the altitude a grav vehicle can hover at as to whether they're really different.

 

A grav vehicle that can hover at any altitude is really an aircraft, and IMO, would be designed as such - more akin to a helicopter, Star Wars Snow Speeder, a dirigible or an airplane than a ground vehicle like a Tank or Humvee. A grav vehicle which can't hover more than a few meters off the ground is going to adhere more to "traditional" ground vehicle design mentalities.

 

Since I'm thinking of ground vehicles, I lumped air-cusion and grav together.

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If you look at the two primary modes of vehicle propulsion wheeled vs tracked you get the following advantages/disadvantages. With wheeled vehicles you get greater mobility and less cost with easier maintanence. Though mobilty of wheeled vehicles can be greatly hampered by terrain. You might think taking a wheeled vehicle over open terrain is always easy, but after an hour or two of getting bounced around your crew will be exausted. So tracked vehicles can be more mobile in areas where roads are uncommon. The Germans discovered this during Operation Barbarossa against the Soviets. The USSR's road system was so poor that the German armies, who depended a great deal on wheeled transportation, often found it difficult to move across the Russian steppes. Especially when weather conditions included snow or rain (mud). Tracked vehicles tend to have heavier weights which can lead to 2 serious problems. One is fuel consumption. Because they tend to weigh significantly more they consume a heck of a lot of fuel compared to a wheeled vehicle. Also, crossing bridges can be problematic for tracked vehicles. Finding a bridge capable of handling 30, 40, up to 70 ton vehicles aint always easy. I agree with the earlier posts on siluettes. "Standing tall" on the modern battlefield is a death sentence. Though their are ways to try and compensate for that. A force shield of some kind capable of defeating incoming fire would adress this. Also armor of some kind capable of withstanding direct hits from an opponent is another solution, if your dead set on operating high siluette vehicles. A few folks have already posted on the inherent vulnerability of wheeled vehicles tires. While that's true many modern military vehicles are capable of running even after the loss of a wheel. Also tires that reseal themselves after small arms hits are common today. Very similar to the "fuel bladders" combat fighters started to use during WW2 to help prevent fires and explosions when fuel tanks would get hit. Ok I've rambled enough...

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Tracked vehicles tend to have heavier weights which can lead to 2 serious problems. One is fuel consumption. Because they tend to weigh significantly more they consume a heck of a lot of fuel compared to a wheeled vehicle. Also, crossing bridges can be problematic for tracked vehicles. Finding a bridge capable of handling 30, 40, up to 70 ton vehicles aint always easy.

This is actually one of the things that brought me to posting this thread. One of the reasons tracked vehicles are so much heavier than a wheeled counterpart are the weight of the treads themselves (the other main reason being the tracks have a higher surface contact area, and thus can support a heavier vehicle for the same pounds per square inch). Anyway, almost all tracked combat vehicles have very heavy metal mechanical track sections. At some point, I have to believe this will change - some materials engineer will figure out a better material to make the track from - right? But what kind of alternatives might be possible? And how will those possibilities change the look of a track?

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