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[Urist Da Vinci]

this is called super-collision. if you stack 7 balls each 7 times more massive than the one above, and drop them from a meter, the top one could reach earth escape velocity (if it survived the impact)

Thats unlikely to happen. Ignoring energy losses due to friction, air resistance, and inelasticity, if all the KE from the balls went into the smallest ball it would be travelling at 1641 m/s, somewhere between mach 4 and mach 5. Earth surface escape velocity is around 11200 m/s. Low earth orbit velocity is 7800 m/s. Go play Kerbal Space Program, you will understand.

This is spitballing because i havent used carts yet, but would the adamantine cart lose speed if it had magma dumped across its path and was then used to launch said magma?

Yes, magma or water slow down carts. If you submerged the cart to fill it, it may come to a halt.

[Larix]

I made two videos, one of the full-speed impulse-ramp powered adamantine shot, another of the powered contraption that reaches terminal velocity just through rollers and collisions.

http://mkv25.net/dfma/movie-2652-supersoniccartfinalcut

and

http://mkv25.net/dfma/movie-2651-poweredflight

I added links to the original post.

[MDFification]

Now all you need to do is cage a goblin 'volunteer' and find out what kind of g-forces a living creature can sustain.

... if you want to go full crimes against humanity, that is.

[Urist McRas]

This is spitballing because i havent used carts yet, but would the adamantine cart lose speed if it had magma dumped across its path and was then used to launch said magma?

I wonder, would a cart loose speed if it had a creature inside that grows from child to adult and thus increasing it's mass?

[Urist Da Vinci]

...

I wonder, would a cart loose speed if it had a creature inside that grows from child to adult and thus increasing it's mass?

No, the velocity of the cart stays constant when the creature changes size. This situation doesn't have a real-life analogy.

Also, riding a moving cart and then exiting the cart doesn't change the cart's velocity. This makes sense only if you fall out and don't jump away/push off.

[Urist McRas]

...

I wonder, would a cart loose speed if it had a creature inside that grows from child to adult and thus increasing it's mass?

No, the velocity of the cart stays constant when the creature changes size. This situation doesn't have a real-life analogy.

Well, then it's a matter of time till someone reaches orbital speed in a cart.

[Whackjob]

Didn't read the whole thread, but couldn't you have the supersonic, lightweight cart go through a pool of water halfway down the "barrel" and fill it with water to arm it with some more mass?

Go play Kerbal Space Program, you will understand.

[TheDarkStar]

Whackjob showed up here, too! I wonder what kind of gigantic DF thing he will make?

[Whackjob]

Oh, I've been a DF fan even longer than I've been a KSP fan.  I'm just not any good at DF just yet.  Still climbing the learning precipice.

[Urist Da Vinci]

Didn't read the whole thread, but couldn't you have the supersonic, lightweight cart go through a pool of water halfway down the "barrel" and fill it with water to arm it with some more mass?

Go play Kerbal Space Program, you will understand.

http://i.imgur.com/2wjL94M.png

Nope, because the cart has to spend a tick or two in a tile with a certain depth of water in order to gain more water, and the water friction would greatly slow down the cart. This would kind of defeat the purpose.

That ship of yours is ominous and terrifying.

[Whackjob]

That ship of yours is ominous and terrifying.

Could be worse.  It could be a little rover.

http://i.imgur.com/fPQBKts.png

[Larix]

Didn't read the whole thread, but couldn't you have the supersonic, lightweight cart go through a pool of water halfway down the "barrel" and fill it with water to arm it with some more mass?

Go play Kerbal Space Program, you will understand.

http://i.imgur.com/2wjL94M.png

Nope, because the cart has to spend a tick or two in a tile with a certain depth of water in order to gain more water, and the water friction would greatly slow down the cart. This would kind of defeat the purpose.

The extra friction would hardly matter - going by the wiki, 7/7 water adds 600 friction. A supercharged cart is already subject to an exceptional friction of 10 000.

The main problem would be the logistics - you'ld have to pump water onto the track itself, because carts moving at derail speed (>50k, which is about 1/30th the speeds we're talking about here) won't enter a downward ramp when coming from flat track. The other question would be if taking on water would trigger a momentum re-calculation, which would reduce speed to something thoroughly uninteresting. It doesn't look like that happens, but i've never checked.

P.S.: oh, expectedly you can trick speeding carts into going down a ramp after all - just use an impulse ramp, like so:

Code: [Select]


##########
═══▲▼..▼══
##########


Cart goes W->E, impulse ramp (e.g. NE) just east of the pit. No extra ramps needed to contain the cart coming back up. Ramps can be on tiles the cart would skip if moving on flat track, ramp transitions automatically force their own movement pattern.

The impulse ramp immediately before the actual down ramp tricks the engine into treating the cart as already moving downwards. Caveat: i've only tried this with an ordinary terminal-velocity cart, not with supersonic carts. Those might get tripped up by the distance conversion around ramps.

[Snaake]

...
P.S.: oh, expectedly you can trick speeding carts into going down a ramp after all - just use an impulse ramp, like so:

Code: [Select]


##########
═══▲▼..▼══
##########


Cart goes W->E, impulse ramp (e.g. NE) just east of the pit. No extra ramps needed to contain the cart coming back up. Ramps can be on tiles the cart would skip if moving on flat track, ramp transitions automatically force their own movement pattern.

The impulse ramp immediately before the actual down ramp tricks the engine into treating the cart as already moving downwards. Caveat: i've only tried this with an ordinary terminal-velocity cart, not with supersonic carts. Those might get tripped up by the distance conversion around ramps.

I've also been able to get carts to go down ramps while at terminal velocity (achieve by a >100-z drop onto a string of downward ramps + several impulse ramps) by using a wall directly after the down-ramp tile (which is of course actually an up ramp on the z below). I got it from this thread. I assume that the "get the cart to go down the ramp" portion could be used even without magma, i.e.

#######
══▼#▼══
#######

and on the z below:
#######
##▲=▲##
#######


I presume this behaviour is a shortcut/exception in the code/intended behaviour, to allow for diagonal 45° tunnels downwards, instead of the cart bumping into the wall ahead of it each z-level, then dropping down onto the ramp, and repeating the same the next z-level (or at least every few z-levels, once it reaches vertical derail speed).


edit: the obvious next step is to try and implement this, and test the weaponization potential of the resulting dwarven water railgun. Since collision damage is apparently calculated off momentum, and shotgunned water is already known to impact as a pretty massive boulder, this technology would create some truly MASSIVE impacts. Or not, if submersion in water resets momentum, or if taking on water recalculates speed (to conserve momentum instead of increased total momentum), or if shotgunned items' speed is set to the minecart terminal velocity or lower. If taking on water/magma increases the momentum due to speed not changing (more than by the usual supercharged friction effect) but the cart becoming heavier, then the cart itself may still be usable as the railgun projectile. Or boosting the momentum of already-supercharged carts like this may be used to simplify/compact the design.

The real challenge is of course that compared even to the automatic minecart shotgun, the railgun is orders of magnitude more complex to build, requiring multiple stages, "pre-heating" earlier stages, exact timing, several specific materials etc. The materials aren't too hard, though: bloodthorn-oak-willow-adamantine, or 4-step metal version, (heavy platinum-)platinum-lead-zinc, should be doable on any embark with traded materials at least, since bloodthorn and adamantine are nearly guaranteed regardless of biome, and the rest can be traded for. And if you want the even crazier 10-step railgun you need to do some modding and/or get an artifact minecart or two out of exotic materials.

Although, if submersion doesn't wreck the momentum, then water could be used to make some carts heavier to bridge the gaps in the density sequence.

[Larix]

I've also been able to get carts to go down ramps while at terminal velocity (achieve by a >100-z drop onto a string of downward ramps + several impulse ramps) by using a wall directly after the down-ramp tile (which is of course actually an up ramp on the z below). I got it from this thread. I assume that the "get the cart to go down the ramp" portion could be used even without magma, i.e.

#######
══▼#▼══
#######

and on the z below:
#######
##▲=▲##
#######

Hmm, this actually _should_ cause the cart to slam into the wall and stop. It's a "west up east down" ramp on the level below, because on that level, floor is to the east and wall to the west of the ramp.

(Testing...
testing...)

Yup, the design shown just doesn't work. An over-derail cart will shoot over the hole and stops. If the ramp is in the end-of-move spot, the cart falls down into the hole just before the wall (and doesn't get out of the pit again), if it's in the middle of the cart's move, the cart may end up teleporting through the wall. In my tests, the cart would end up on the tile just behind the pit (standing still, without its cargo), or would fall into the hole before the wall. All horizontal speed was lost in either case.

With an impulse ramp immediately before the pit entrance, the cart goes down into the pit, doesn't lose any speed and keeps its cargo.

An under-derail cart would go into the pit and out just fine, but that's not a very useful speed range for shotgun construction. In both cases, the wall doesn't seem to do anything.

P.S. - looking at EvictedSaint's design, the cart there was going from an impulse ramp into the pit. That's why it worked. The wall was very likely completely unnecessary.

P.P.S. - The basic design "impulse ramp - down ramp - flat track below - up ramp - flat track above" works, supercharged carts will enter and leave without significant speed loss and can navigate a water-filled pit as well, but a 3x1 pit is not enough for such a cart to take on water. I'm not familiar with waterguns, so don't know if there's some kind of time requirement or speed limit.

[Snaake]

Ok. Didn't notice that there was also an impulse ramp just before the down ramp. I used EvictedSaint's design in my previous fort and it worked, and while I'm not 100% sure, I probably did copy the relevant part exactly.