Combat and the physics of the Surge of Gravitation

[+Oltux72]

Our aircraft fight each other with guns and missiles. Our preferred position to kill an adversarial aircraft is behind it and often slightly above. This is because

1. Bullets and missiles are much faster than aircraft
2. Sight is best to the front, visually and by radar
3. It is easier to aim the whole aircraft
4. Your missile gets your speed and height

To achieve that position you use maneuver. Aircraft differ in their characteristics for maneuvering by direction. It makes a difference whether you are going up and down versus left or right. Airplanes cannot turn on the spot. A user of gravitaion is quite different. They are failing, not flying aerodynamically. Hence:

1. They can go into full reverse. Changing acceleration 180 degrees is an option.
2. You cannot stall. Any attitude is possible in the air.
3. You cannot be behind and above an enemy. Pursuit means that you are under an enemy.
4. You cannot trade height for speed and vice versa. You are always at the very top and falling.
5. You cannot roll with Gravitation

The weapons are also quite different. Unless you are going straight down, any missile will always fall behind or sideways quickly, as it does not share your acceleration and the speed you can add to a spear is small compared to the speeds you are falling at. And good luck handling bow and arrow or a crossbow under these conditions.

Naively I'd try to get into the position to stab an enemy into the back or to get into grappling range with you facing your enemy's back. Direct pursuit is a bad idea. Anything nasty he drops will hit you. Our maneuvers for air combat as far as they trading potential energy for kinetic energy, will not work.

[Karger]

I actually don't get why the radiants don't invest in a bunch of really small throwing spears/darts that they can just lash several times at short range.

[theTruthshaper]

3 minutes ago, Karger said:

I actually don't get why the radiants don't invest in a bunch of really small throwing spears/darts that they can just lash several times at short range.

The damage will be pretty low? I doubt that these would even annoy the Fused. Now, if they developed explosives...

[Dracnor]

On 09/08/2020 at 6:11 PM, The_Truthwatcher said:

The damage will be pretty low? I doubt that these would even annoy the Fused. Now, if they developed explosives...

Against a fused, indeed, they would heal. But against non-surgebinders... That's terrifying. Use a lot of iron/steel marbles as bullets, and throw them by Lashing 4 or 5 times. At short range, it should be quite effective. (Well, that is if the surgebinder can take several bullets in his hand and lash them all at once, not one by one which would be ineffective).

And with spears/darts, a reduced number of Windrunners/Skybreakers can snipe (from the sky !) the officiers in a ennemy army, changing the tide of battle.

TLDR: I do not want to have to fight radiants without my own surgebinders to counter them x)

[TheOneEyedFox]

On 8/9/2020 at 0:11 PM, theTruthshaper said:

The damage will be pretty low? I doubt that these would even annoy the Fused. Now, if they developed explosives...

This could easily be done by placing an aluminum switch between two gemstones one containing void light the other anti-void light when pressed the aluminum barrier slides out of the way allowing the transfer to begin and can be timed based off material connected the two as well as size. 

 

[The Technovore]

On 8/10/2020 at 9:30 AM, Dracnor said:

Against a fused, indeed, they would heal. But against non-surgebinders... That's terrifying. Use a lot of iron/steel marbles as bullets, and throw them by Lashing 4 or 5 times. At short range, it should be quite effective. (Well, that is if the surgebinder can take several bullets in his hand and lash them all at once, not one by one which would be ineffective).

And with spears/darts, a reduced number of Windrunners/Skybreakers can snipe (from the sky !) the officiers in a ennemy army, changing the tide of battle.

TLDR: I do not want to have to fight radiants without my own surgebinders to counter them x)

Turns out when you think about it Windrunners/Skybreakers can do everything a coinshot can do but better. Imagine a group of windrunners on top of Bridge 4 with bricks just firing them at high speed toward enemies. Imagine a group of windrunner lifting a big o' chunk of rock just to launch it at a thunderclast or unsuspecting group of Fused (a less mobile type of fused).

Leshwi mentioned that Windrunners had homing arrows. I like think about homing boulders. Sure it takes tons of stormlight, but that's what Dalinar's for 

[Aspiring Writer]

On 8/9/2020 at 9:07 AM, Karger said:

I actually don't get why the radiants don't invest in a bunch of really small throwing spears/darts that they can just lash several times at short range.

Oh god, flechettes. How long till they invent flechettes? Combined with a surge of gravitation to go down faster, that will be so goddamn deadly! The singers would just start being massacred. Hell, with gravitation, you can make the flechettes fall sideways and up, so this is useful even against the fused.

[+Oltux72]

1 hour ago, The Technovore said:

Turns out when you think about it Windrunners/Skybreakers can do everything a coinshot can do but better.Imagine a group of windrunners on top of Bridge 4 with bricks just firing them at high speed toward enemies. Imagine a group of windrunner lifting a big o' chunk of rock just to launch it at a thunderclast or unsuspecting group of Fused (a less mobile type of fused).

Well, no. The issue is terminal velocity. It goes up with the square root of gravity. Now consider that Roshar has a lower gravity and denser air than standard. What is the highest lashing we have seen? Twentyfold? Let's be generous and say 25 fold. That will give you 5 times the terminal velocity (of a lower terminal velocity). They will be useless against a target with personal armor.
Yes, Windrunners can use huge boulders, but somebody has to get them to the battle field. And good luck hitting anything with it. And people will see them coming, as their acceleration is worse.

1 hour ago, The Technovore said:

Leshwi mentioned that Windrunners had homing arrows. I like think about homing boulders. Sure it takes tons of stormlight, but that's what Dalinar's for 

Reverse Lashing, I am assume. That raises the interesting question on who can break a reverse lashing.

[The Technovore]

33 minutes ago, Oltux72 said:

Well, no. The issue is terminal velocity. It goes up with the square root of gravity. Now consider that Roshar has a lower gravity and denser air than standard. What is the highest lashing we have seen? Twentyfold? Let's be generous and say 25 fold. That will give you 5 times the terminal velocity (of a lower terminal velocity). They will be useless against a target with personal armor.
Yes, Windrunners can use huge boulders, but somebody has to get them to the battle field. And good luck hitting anything with it. And people will see them coming, as their acceleration is worse.

Mmm, fair, but terminal velocity for a human that's trying to go slow (belly-to-earth) is ~120mph. A brick will have higher density and less drag going for it, but 20-25gs with a lower g and denser atmosphere, which makes your 5x terminal velocity pretty fair, which puts the bricks at ~620mph. Now, that's about a third of the speed of a modern bullet, but it's still really really fast and is still going to impart upwards of 5000N to whoever it hits. (Give or take a order of magnitude). I'm pretty sure that's going to shatter some armor.

I mean even if Roshar's g is around 6 m/s^2, multiply by 20 you get 120 m/s^2. A boulder reaching it's 5x terminal velocity at 120m/s^2 is not the most effective form of artillery, but to a tightly-packed formation of singer troops with non-mobile Fused interspersed within, it's not something to laugh at either. 

And I mean... that's assuming you're lashing a boulder towards the ground. What if you just... lashed it laterally? That's an impact zone in the shape of a cylinder, not a circle, at half-mach speeds. Idk, that's just my speculation, but I don't think it's too far out there that that could be a problem. And as for moving the rocks, I was thinking about the fact that they're fighting on largely stone ground. I mean, there's going to be rocks around there. 

Edited March 23, 2021 by The Technovore

[therunner]

1 hour ago, Oltux72 said:

Well, no. The issue is terminal velocity. It goes up with the square root of gravity. Now consider that Roshar has a lower gravity and denser air than standard. What is the highest lashing we have seen? Twentyfold? Let's be generous and say 25 fold. That will give you 5 times the terminal velocity (of a lower terminal velocity). They will be useless against a target with personal armor.

Reverse lashing Kaladin used against Pursuer to tear his head off was around strength of ~140 lashings (force applied should have been around 5000N, head weighs around 5kg), so I would assume that at least 50 lashings is easily realistic for 4th oath Windrunner.

Usual earth brick has mass ~3kg, and size around 20 cm x 10 cm x 5 cm (roughly).

On Roshar with gravitational acceleration 7m*s^(-2) we would get for a brick of mass 3kg, with air density 2 kg*m^(-3) (almost twice as much as Earth), surface area to air 200 cm^2 and of drag coefficient 1.02 (we assume they fire it the bigger face first, so not optimaly) we would get terminal velocity of 100 m/s, so 360 km/h. With 25 lashing this would be around 1500 km/h. THIS IS INCORRECT, SEE EDIT

If they took the same brick but lashed it the smallest face first (to minimize drag) they would have surface area ~50 cm^2 and drag coefficient only around 0.82, and the terminal velocity would now be 226 m/s, so whooping ~800km/h. With 25 lashings this would be 4000km/h, which is quite insane (the kinetic energy of the projectile would be ~2MJ, so about the same as a very heavy car at 80 km/h). THIS IS INCORRECT, SEE EDIT

Also, if the brick still has lashings left it will continue to try and accelerate even after impact, potentially pushing inside softer targets.

EDIT: In the above calculations I made a mistake and overestimated the results by ~3.2. The true terminal velocity in the first case is 31 m/s, so 112 km/h, in the second case 71 m/s so about 255 km/h. With 25 lashings the speeds go to 550 km/h, and ~1250 km/h in the second case.

Edited March 23, 2021 by therunner
I made a mistake in the calculation

[Bejarden]

What’s the practicality of using so much Stormlight per brick.

How large can each Boulder be? Is it worth the time to lose a Windrunner that could have been on the ground at that time?

 

[Zapata]

1 hour ago, Oltux72 said:

Reverse Lashing, I am assume. That raises the interesting question on who can break a reverse lashing.

I thought that the Windrunner had to be touching the object they lash. maybe the homing arrows were tied to a rope so they could stay "touching" the Windrunner while moving toward the target. that is if the Reverse Lashing would actually work like that anyway. The Reverse Lashings have always been weird, they seem almost like they use some form of Spiritual Adhesion almost.

[Aspiring Writer]

Why are we all so focused on bricks? if they decide to use this tactic, they will just make something more aerodynamic to reduce drag and more likely to pierce armor/carapace. bricks would only be used if they didn't have the necessary resources.

[The Technovore]

31 minutes ago, Bejardin1250 said:

What’s the practicality of using so much Stormlight per brick.

How large can each Boulder be? Is it worth the time to lose a Windrunner that could have been on the ground at that time?

 

Not so much practicality so much as understanding the versatility. Windrunners in RoW rely on their sprenblades (because they're awesome and powerful), but with their surges a windrunner army is more formidable and versatile than a coinshot army by far. Perhaps launching a couple boulders wouldn't do much for all the stormlight you spend, but right now Windrunners rely on melee combat and using gravitation to close the distance. However, by carrying around a couple heavy projectiles (a pouch of heavy lead balls?) they could have access to a very powerful ranged weapon. 

Thanks to @therunner for the better math than I had. 

20 minutes ago, Bearer of Agonies said:

I thought that the Windrunner had to be touching the object they lash. maybe the homing arrows were tied to a rope so they could stay "touching" the Windrunner while moving toward the target. that is if the Reverse Lashing would actually work like that anyway. The Reverse Lashings have always been weird, they seem almost like they use some form of Spiritual Adhesion almost.

For sure, I don't know how it's possible, but the Fused say that it is. It just seems to me that using arrows, instead of something that carries more impact, seems like a waste of potential.

Edited March 23, 2021 by The Technovore

[Bejarden]

4 minutes ago, The Technovore said:

For sure, I don't know how it's possible, but the Fused say that it is. It just seems to me that using arrows, instead of something that carries more impact, seems like a waste of potential.

Edited 2 minutes ago by The Technovore

I was thinking you have a few Radiants fighting the fused and they infuse something while fighting with a R lashing then the arrows are directed toward that spot

[Zapata]

7 minutes ago, Bejardin1250 said:

I was thinking you have a few Radiants fighting the fused and they infuse something while fighting with a R lashing then the arrows are directed toward that spot

still, when using a reverse lashing, you need to be constantly touching the object

[Bejarden]

 

You touch a fused right before a arrow reaches him and then all the Arrows go to that area with much more accuracy 

[Zapata]

1 minute ago, Bejardin1250 said:

 

You touch a fused right before a arrow reaches him and then all the Arrows go to that area with much more accuracy 

that's possible, but that would take perfect timing to accomplish. seems more likely that there's a way of using the Reverse in a way we haven't seen yet, or just arrows on ropes

[Bejarden]

True, very true

 guess someone will need to ask Brandon

[+Oltux72]

16 hours ago, The Technovore said:

Mmm, fair, but terminal velocity for a human that's trying to go slow (belly-to-earth) is ~120mph. A brick will have higher density and less drag going for it, but 20-25gs with a lower g and denser atmosphere, which makes your 5x terminal velocity pretty fair, which puts the bricks at ~620mph. Now, that's about a third of the speed of a modern bullet, but it's still really really fast and is still going to impart upwards of 5000N to whoever it hits. (Give or take a order of magnitude). I'm pretty sure that's going to shatter some armor.

Bricks have about two times the density of a human being. And cube/square is against you.
Anyway, of course, you could use a lump of lead. It is likely possible for a Windrunner to lug something around that would kill. But how many bricks can they carry? A dozen?
How many coins can a coinshot carry? And that is the issue. A short range, coinshots are superior.

15 hours ago, therunner said:

EDIT: In the above calculations I made a mistake and overestimated the results by ~3.2. The true terminal velocity in the first case is 31 m/s, so 112 km/h, in the second case 71 m/s so about 255 km/h. With 25 lashings the speeds go to 550 km/h, and ~1250 km/h in the second case.

You need to hold a thing you want to lash. Can you really hold what is heavy enough to kill while it is pulled at 10g away from you?

 

15 hours ago, Bearer of Agonies said:

I thought that the Windrunner had to be touching the object they lash. maybe the homing arrows were tied to a rope so they could stay "touching" the Windrunner while moving toward the target. that is if the Reverse Lashing would actually work like that anyway. The Reverse Lashings have always been weird, they seem almost like they use some form of Spiritual Adhesion almost.

You have to touch in order to lash. But you need not keep touching an object to keep it lashed. Once it is lashed it will happily fall in the wrong way until it runs out of Stormlight.

Does the same apply for Reverse Lashings?

[therunner]

21 minutes ago, Oltux72 said:

Bricks have about two times the density of a human being. And cube/square is against you.
Anyway, of course, you could use a lump of lead. It is likely possible for a Windrunner to lug something around that would kill. But how many bricks can they carry? A dozen?
How many coins can a coinshot carry? And that is the issue. A short range, coinshots are superior.

Cube/square here actually works in favor of Windrunners, if you enlarge object 5x in all directions its mass grows 5^3, but its surface area grows only 5^2. Since for terminal velocity mass is divided by area facing the wind, larger objects of equal density fall faster than smaller objects (v~sqrt(m/A), so for 5 fold increase in every direction m->5^3m but A->5^2A, so v->sqrt(5)v, and terminal velocity is greater for the bigger object).

In short range coinshot is definately superior, but from distances larger than ~100m Windrunner would fire faster projectiles.

21 minutes ago, Oltux72 said:

You need to hold a thing you want to lash. Can you really hold what is heavy enough to kill while it is pulled at 10g away from you?

True, It depends on how fast you can apply lashings and if you can apply multiple lashings at once.

21 minutes ago, Oltux72 said:

You have to touch in order to lash. But you need not keep touching an object to keep it lashed. Once it is lashed it will happily fall in the wrong way until it runs out of Stormlight.

Does the same apply for Reverse Lashings?

As far as we know Reverse lashings requires touch to maintain. But mentions in RoW about Windrunners of old using homing arrows suggests that there is a way around it.

Edited March 24, 2021 by therunner

[+Oltux72]

1 hour ago, therunner said:

Cube/square here actually works in favor of Windrunners, if you enlarge object 5x in all directions its mass grows 5^3, but its surface area grows only 5^2. Since for terminal velocity mass is divided by area facing the wind, larger objects of equal density fall faster than smaller objects (v~sqrt(m/A), so for 5 fold increase in every direction m->5^3m but A->5^2A, so v->sqrt(5)v, and terminal velocity is greater for the bigger object).

If you compare to a coin. But not if you compare to a human being.

1 hour ago, therunner said:

In short range coinshot is definately superior, but from distances larger than ~100m Windrunner would fire faster projectiles.

At those distances you might hit a ship or a building, but nothing smaller.

1 hour ago, therunner said:

As far as we know Reverse lashings requires touch to maintain. But mentions in RoW about Windrunners of old using homing arrows suggests that there is a way around it.

When Kaladin played locksmith, did he touch the objects?

[therunner]

7 minutes ago, Oltux72 said:

If you compare to a coin. But not if you compare to a human being.

At those distances you might hit a ship or a building, but nothing smaller.

When Kaladin played locksmith, did he touch the objects?

True, you need to compare objects of similar density for cube/square to make sense.

True, unless they fire a lot of smaller objects, kinda like a shotgun.

When did he play locksmith, it escapes my memory?

[Bejarden]

14 minutes ago, therunner said:

When did he play locksmith, it escapes my memory?

In RoW he uses a reverse lashing to unlock a door

[Zapata]

56 minutes ago, Oltux72 said:

When Kaladin played locksmith, did he touch the objects?

He did not touch the latch, but touched a pane of glass and pulled the latch to the glass.