Compounding's Exact Mechanics and Limitations

[therunner he/him]

23 minutes ago, StanLemon said:

Considering that Marasi was leaving a noticeable vacuum and air fills a vacuum at approximately 500 m/s, she was most likely going at least that fast. Honestly she almost probably going even faster as she probably wasn't moving her hand more than a few centimeters so it would have only taken a fraction of a second to fill that vacuum. 

If we assume that your equation is correct then the amount of speed that was stored in the steel was even more than 17000 months estimate

Her perception was also sped up ~40-45x times (if moving at Mach 1), and even then she mentions she saw pockets of vacuum and only briefly. So if the vacuum formed only for ~0.0023 seconds, it would translate to 0.1 seconds of her perception which would still be noticeable.
500 m/s is good approximation for speed (it was freezing so the speed would be lower by ~5%), and in that time the air would travel 1 meter, so there is a discrepancy.

Also, the pockets must have been small, otherwise they would have made quite noticeable sound.

However, the gap is not that gigantic.

Edit: Two more funny things:

1. The air/vacuum shockwave actually moves far faster, typically around ~1700m/s, and she clearly was not moving at those speeds (the sonic boom would be huge).
2. The speeds at which you can create not even vacuum, just even region of 1% air density are ~2-3000 m/s for large objects. For smaller object they would be magnitude greater (circa 20000 m/s).

Basically, what happens there is incredibly out of order and the side-effects on people nearby would be basically deadly, if we take it at face value.

Edited March 22, 2023 by therunner

[Trusk'our he/him]

24 minutes ago, therunner said:

Her perception was also sped up ~40-45x times (if moving at Mach 1), and even then she mentions she saw pockets of vacuum and only briefly. So if the vacuum formed only for ~0.0023 seconds, it would translate to 0.1 seconds of her perception which would still be noticeable.
500 m/s is good approximation for speed (it was freezing so the speed would be lower by ~5%), and in that time the air would travel 1 meter, so there is a discrepancy.

Also, the pockets must have been small, otherwise they would have made quite noticeable sound.

However, the gap is not that gigantic.

Edit: Two more funny things:

1. The air/vacuum shockwave actually moves far faster, typically around ~1700m/s, and she clearly was not moving at those speeds (the sonic boom would be huge).
2. The speeds at which you can create not even vacuum, just even region of 1% air density are ~2-3000 m/s for large objects. For smaller object they would be magnitude greater (circa 20000 m/s).

Basically, what happens there is incredibly out of order and the side-effects on people nearby would be basically deadly, if we take it at face value.

Well, dang.

I guess that's yet another reason to fear steel Compounding.

[StanLemon]

18 minutes ago, therunner said:

Her perception was also sped up ~40-45x times (if moving at Mach 1), and even then she mentions she saw pockets of vacuum and only briefly. So if the vacuum formed only for ~0.0023 seconds, it would translate to 0.1 seconds of her perception which would still be noticeable.
500 m/s is good approximation for speed (it was freezing so the speed would be lower by ~5%), and in that time the air would travel 1 meter, so there is a discrepancy.

Also, the pockets must have been small, otherwise they would have made quite noticeable sound.

However, the gap is not that gigantic.

Edit: Two more funny things:

1. The air/vacuum shockwave actually moves far faster, typically around ~1700m/s, and she clearly was not moving at those speeds (the sonic boom would be huge).
2. The speeds at which you can create not even vacuum, just even region of 1% air density are ~2-3000 m/s for large objects. For smaller object they would be magnitude greater (circa 20000 m/s).

Basically, what happens there is incredibly out of order and the side-effects on people nearby would be basically deadly, if we take it at face value.

Ah good point 

[Mistchemist16]

5 minutes ago, Trusk'our said:

Well, dang.

I guess that's yet another reason to fear steel Compounding.

To be fair, most steel Compounders don’t even need to operate at that level. In WoA, Elend tries fighting a Thug and the speed difference leaves Elend’s movements looking sluggish. Just tap x5 speed and even Thugs have that problem. They also don’t need to literaly dodge bullets every time. They just need to be fast enough to avoid an enemy aiming at them.

Of course, that’s not the most fun part of Steel Compounding. I’d love to see bursts of moving faster than they eye can see, like an anime character. I’d love to see bullet dodging and maybe even some Bands level tricks. But realistically, even a Steel Compounder can’t keep crazy speeds forever nor do they particularly need to if they can get something more like a pewter speed advantage. Thankfully, their metal is common and so they can load up even easier than Miles.

[Trusk'our he/him]

6 minutes ago, Mistchemist16 said:

To be fair, most steel Compounders don’t even need to operate at that level. In WoA, Elend tries fighting a Thug and the speed difference leaves Elend’s movements looking sluggish. Just tap x5 speed and even Thugs have that problem. They also don’t need to literaly dodge bullets every time. They just need to be fast enough to avoid an enemy aiming at them.

Of course, that’s not the most fun part of Steel Compounding. I’d love to see bursts of moving faster than they eye can see, like an anime character. I’d love to see bullet dodging and maybe even some Bands level tricks. But realistically, even a Steel Compounder can’t keep crazy speeds forever nor do they particularly need to if they can get something more like a pewter speed advantage. Thankfully, their metal is common and so they can load up even easier than Miles.

True. It really doesn't take much added speed to become a serious threat and as cool as it would be to see a Steelrunner going Mach one or two, it's not going to be their most efficient strategy. 

It would be pretty interesting to see a BoM level individual going up against an army of Fused at some point. They probably wouldn't even know what hit them 

[therunner he/him]

53 minutes ago, Trusk'our said:

Well, dang.

I guess that's yet another reason to fear steel Compounding.

I don't think so actually, we know that they are not immune to wind resistance, and at ~2000m/s, they would start burning up very fast, and their metalminds would melt.
Fullborn could mitigate some of it, but still only up to a point.

From reader's/writers perspective, if BoM was to give us a taste of what Fullborn can be like, then the authorial intent seems to be that even low Machs are a lot for Compunder.
But I am incredibly excited to see what they can pull off actually (and to have some precise numbers!)

[Trusk'our he/him]

3 minutes ago, therunner said:

From reader's/writers perspective, if BoM was to give us a taste of what Fullborn can be like, then the authorial intent seems to be that even low Machs are a lot for Compunder.
But I am incredibly excited to see what they can pull off actually (and to have some precise numbers!)

You said it!

Edited March 22, 2023 by Trusk'our

[cometaryorbit]

On 3/22/2023 at 8:40 AM, Mistchemist16 said:

To be fair, most steel Compounders don’t even need to operate at that level. In WoA, Elend tries fighting a Thug and the speed difference leaves Elend’s movements looking sluggish. Just tap x5 speed and even Thugs have that problem.

Well, Pewter Allomancy gives not just a speed boost but also a lot of extra precision/grace/dexterity - someone using Pewter Allomancy (if they start at average speed) might not be much if any faster than an Olympic runner, but they can use that speed much more effectively.

So I think a F-Steel user moving twice as fast as the A-Pewter user might be a fairly even match... but yeah x5 normal might be pushing it, especially if Pewter is more like x1.5 speed + super endurance rather than really a big speed boost.