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A sandcrawler is is a tracked vehicle about 40 meters long, 20 meters tall, and 15 meters wide. It has a thick outer hull for protection from the elements. It has eight sets of tracks, four abreast forward and aft for support. It is designed to operate in hot and sandy desert environments. In the Star Wars universe, this vehicle is the Jawas' primary means of transport around Tatooine.

From an engineering perspective, how practical would such a vehicle be?

I imagine that the high center of mass would pose stability issues, especially over uneven terrain, and the eight sets of tracks would severely limit speed.

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    $\begingroup$ Also, site for questions on already built worlds in published works is scifi.stackexchange.com $\endgroup$ – Mołot Jan 11 '18 at 11:42
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    $\begingroup$ Please describe the concept of a Sandcrawler for those that are not familiar with this vehicle. Especially with a focus on what you think the important parts are for this question. Maybe you could include a small picture or sketch to illustrate your ideas. $\endgroup$ – Sec SE - clear Monica's name Jan 11 '18 at 12:00
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    $\begingroup$ @a4android the scifi exchange takes tech questions for star-wars vehicles, I even posted one myself $\endgroup$ – dot_Sp0T Jan 11 '18 at 13:23
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    $\begingroup$ I feel like people are being a little too un-helpful with this question. I edited the question with a quick description. Just because a vehicle is like something from an already created universe, doesn't mean we can't discuss it here. If you are looking to incorporate a sandcrawler into your own world, that would be on topic, regardless if someone had though up the idea first. This question should not be closed. $\endgroup$ – kingledion Jan 11 '18 at 16:19
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    $\begingroup$ @kingledion Agreed. The question is about the practicality of this type of vehicle. Anyone could post the same question describing the vehicle without any Star Wars references and it would be acceptable as worldbuilding. $\endgroup$ – a4android Jan 12 '18 at 0:38
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Depending on what you want to do with it, it might be a good or a bad design. The number you give do not completely fit with the picture but don't sound so bad.

So not giving it any from gives the following shape with a center of mass about 7.5 m above the ground.

Schematic of the sandcrawler

So do you have any change of tipping over in rough terrain? If you go nose first everything is probably ok, sideways gives more danger but not as much as you would suspect. The tipping point is if the Center of Mass (CoM) lays outside the base, this only happens after a tilt of 40 degrees as can be seen in the picture.

Tipping of the sandcrawler

So what is the ground pressure it has. To calculate this you need the weight of the crawler and the area of the tracks. For the area of the track I took half the area of the bottom. For the weight I took 140 time the weight of the Maus as this is the biggest tank build and this is roughly how many times the Maus fits in the crawler. I think I am highly over estimating the weight since the armoured plating only has to be on the outside so I took half the weight, but you can use any number you want.

So the ground pressure exerted by the crawler becomes:

Formula

Ok so this is a bit heavy but it is somewhere between a montouain bike and a road racing bike, see this reference, wikipedia of course.

If the weight reduced (which I think is logical) and add slightly more track surface the contraption seems feasible. Whether it is usable depends on the application.

One note on speed, since it is such a huge mass with relative high CoM you need to take care of the inertia of the crawler. Any slightly tight cornering at higher speed will cause it to tip over.

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    $\begingroup$ If most of the crawler's weight (Engines and track assembly, perhaps) is towards the bottom of the vehicle then the COM can be much, much lower. There are a few kids toys that abuse this effect to make seemingly impossible objects. $\endgroup$ – Joe Bloggs Jan 12 '18 at 9:37
  • $\begingroup$ @Joe, Good comment, I indeed used a homogeneous mass distribution due to lack of data. The OP can split the vehicle in different sections with different masses and add the weighted CoM of each component to get the actual center of mass of the entire body to get a more accurate answer. $\endgroup$ – D.J. Klomp Jan 12 '18 at 14:01
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The Sandcrawler is hilariously badly designed for any kind of realistic use. The fact that it is so thin from one direction means that the incredible weight of the thing would cause it to sink into the sand.

We already had problems with sinking into mud and sand during WW2 with heavy tanks like the Tiger and the KV. And at least those had wide bottoms to spread out the weight which meant it didn't sink into the ground as easily. The Sandcrawler is 10 times the size with a terrible weight distribution. It would really only be usable on a planet with a hard rock surface. It would sink into any ground that was even remotely soft.

And the biggest problem with the treads isn't that they'd be slow. Modern tanks can go quite fast with an M1 Abrams having a top speed of 60mph (96.5 km/h). The problem with the sand crawler's is that the treads are so close together turning would be a slow tedious nightmare.

If used in warfare it would be a massive target as well and any attempt to armor it would only exacerbate the aforementioned issues.

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    $\begingroup$ /The problem with the sand crawler's is that the treads are so close together turning would be a slow tedious nightmare/ - excellent $\endgroup$ – Willk Jan 11 '18 at 19:40
  • $\begingroup$ Sandcrawlers aren't designed for warfare to begin with (they're scavenger vehicles), so that point and the slowness don't really matter. $\endgroup$ – JAB Jan 11 '18 at 23:00
  • $\begingroup$ Would allowing the treads (Maybe pairs?) to pivot help with the turning? Or would that make the whole thing tip over like just about anything else? $\endgroup$ – Andon Jan 12 '18 at 0:39
  • $\begingroup$ Although, to be fair, the design realistically doesn't have to worry about tipping over, since it's just going to sink into the ground anyway. $\endgroup$ – Andon Jan 12 '18 at 0:40
  • $\begingroup$ @Andon Honestly, the whole thing is so top heavy any shift from 90 degrees in either direction might tip it over. $\endgroup$ – Elazertwist Jan 12 '18 at 0:48

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