Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - byron

Pages: [1] 2 3 ... 59
1
C# Aurora / Re: C# Aurora Changes Discussion
« on: November 13, 2017, 01:31:43 PM »
My comments were based on the results of testing nuclear weapons in space:

https://history.nasa.gov/conghand/nuclear.htm
I'm reasonably familiar with those results.  All of the energy from the weapon has to go somewhere.  To a first approximation, how badly you are hurt depends on how much energy you get hit with and how durable you are.  There's nothing magic about blast which makes it so much more damaging than the flood of X-rays you get in space.  Spaceships are durable, but so are lots of other things (just not houses, which may, admittedly, be specifically vulnerable to blast).  And space is big, so you're less likely to get multiple targets close enough together to be killed with one hit. 
See http://www.projectrho.com/public_html/rocket/spacegunconvent.php#id--Nukes_In_Space for more details.

Re the behavior of missiles and damage pattern, we can probably reconcile it with only a bit of handwaving.  Maybe there's some sort of focusing being used (see Casaba-Howitzer in the link above) or maybe TN materials are so tough it has to get close enough to start to show near-field effects. 

2
C# Aurora / Re: C# Aurora Changes Discussion
« on: November 13, 2017, 12:17:58 PM »
Also, nukes in space are far less powerful than nukes in atmosphere (well, less powerful in heat/blast but more powerful in radiation terms)
This isn't really true.  There are two major differences.  First, space is big, and thus you aren't likely to have multiple targets within the damage radius because things are spread out more.  Second, spacecraft are pretty durable.  There are durable things on Earth, too, but most people's perceptions of nuclear weapons are shaped by very flimsy Japanese houses getting knocked over and dramatic test footage that doesn't give a good sense of scale. 

3
C# Aurora / Re: C# Aurora Changes Discussion
« on: November 06, 2017, 12:06:17 PM »
From what I understand we are descendent of rodents which survived from the Dinosaurs by digging underground not that long ago...

So if you want a more scientific explanation: What if that asteroid that wipes the dinosaurs out never hits Earth but intelligent life develop underground by necessity of hiding from the big beasts instead?
A lot of animals burrow to get shelter.  Very few of them live exclusively underground.  Those that do tend to be smaller, because moving underground isn't very energy-efficient, and being big means that you need to cover a lot of territory looking for food.

4
C# Aurora / Re: C# Aurora Changes Discussion
« on: November 06, 2017, 11:40:09 AM »
What says that anything besides the leaves of the vegetation need to be above the surface?
The bit where I can get more energy from my neighbor by being taller than him.  And the bit where I don't have to push stuff out of the way to grow.

I'm not saying that underground life is impossible, just that I wouldn't expect complex life to occur entirely underground. 

5
C# Aurora / Re: Replacing PDCs
« on: November 06, 2017, 08:25:28 AM »
If a steel round only penetrates up to 6 times its length in ground once sufficiently large speeds are achieved and you can form needles of arbitrary lengths on demand you've basically got the perfect fortress breaking round right there. Only thing you need to do is relative densities and how far down you need to go and the round stops right as it has passed the reinforced concrete. And if it doesn't, it hits with enough force to make it moot anyway.
That's not quite how it works.  6x depth is based on the Newtonian/hydrodynamic penetration approximation.  Basically, at some point your ability to penetrate is limited by your ability to push things out of the way, regardless of how fast you're going.  However, at higher speeds you start making craters, which can penetrate deeper.  Even if you're not quite to proper cratering, all of that energy has to go somewhere, which is likely to be unpleasant to those nearby.

6
C# Aurora / Re: Replacing PDCs
« on: November 06, 2017, 07:39:51 AM »
Also, a steel round hitting dirt will only penetrate about 6 times it's length. All the extra kinetic energy will go outwards and make a crater.
That's going to be dominant at really high velocities.  Long rods are still useful for armor penetration at tens of km/s.  In Aurora, you probably couldn't tell the difference.  The near future is a rather different matter.

7
C# Aurora / Re: C# Aurora Changes Discussion
« on: November 06, 2017, 07:35:32 AM »
What about planets where all life evolved subterranian? Hivemind insect homeworlds and so on?
What's your energy source there?  Life is on the surface because the energy is there.  Yes, I know about extremophiles living in deep-sea vents or geysers in Yellowstone.  But the surface seems overwhelmingly likely, particularly for complex life.

Re terrain, fantastic to hear.  I can't wait to try it out.  How fast does terrain change during terraforming?  Creating jungle mountains on your fortress world sounds great, but unless you're actively seeding, I can't see how it could grow in less than a couple centuries.  Even with seeding, it would probably take decades.

8
C# Aurora / Re: Replacing PDCs
« on: November 03, 2017, 12:53:33 PM »
This isn't exactly true.  A railgun round is denser than a traditional battleship round.  Aerodynamics, including wind, correlate with the density of the round, not just the surface area or volume.  A stone ball with a diameter of 1m, thrown at 20m/s will go further than an inflated rubber ball of the same diameter at the same speed.  Because the rubber ball is less massive, the force of drag affects it more.
If we're going to be really pedantic, the actual controlling factor is sectional density, mass/unit area.  Tungsten is ~2.5x as dense as steel.  (HE content of US AP shells was very low, and can be ignored at this scale.)  Mass scales with the cube of size, area with the square.  So a tungsten shell with the same sectional density will be 40% of the size of an equivalent battleship shell.  For a US 16", that means 6.4" diameter and about 2.5' long.  This is considerably bigger than a railgun shell being hypothesized.  Playing with the shape of the railgun round doesn't help, because what you gain in one dimension you lose in the others.
(OK, the actual controlling number is ballistic coefficient, but assuming similar shapes that drops out to sectional density.  And a long rod is more vulnerable to crosswinds than a normal shell, so that doesn't help the railgun, either.)

9
C# Aurora / Re: Replacing PDCs
« on: November 03, 2017, 12:19:45 PM »
Ofcourse there is...

What you need to understand is that inaccuracy depends on unplanned deviation during projectile travel which scales linearly with travel time. ( deviations in course both from a moving target and on the projectile itself ).
Battleship gunnery is a major interest of mine, to the point I've read several books mostly or wholly devoted to the subject, and written a couple of essays on it.  So yes, I know that's one cause of inaccuracy.  But only one.  If it was the major one, then I'd expect that it would affect all shells in a salvo equally, and that the primary cause of misses would be tight patterns landing off-target.  This is not really the case.  Pattern size was often greater than Mean Point of Impact error.  Yes, I'd expect a railgun to be better at consistency than a WWII-era 16" gun.  If nothing else, you have a lot lower variation in muzzle velocity.  But not enough to make unguided KE rounds work at >10 km. 

Quote
If a railgun projectile travels at 5km/s compared to a battleship shell at 500m/s this means the projectile can travel 10 times as long distance before the inaccuracy from outside influence becomes identical.
That assumes the railgun projectile is the same size as the battleship shell.  This is not true.  It's considerably smaller, which means it's much more affected by wind.  Look at a 5" vs 16" range table if you don't believe me.
That aside, let's assume you're right.  Typical battleship pattern size for a 3-gun salvo was about 1% of range.  We'll take 10% of that.  At 36 km (outer limits of battleship range) you're still missing by an average of 18m (1% is diameter, not radius).  An M1 tank has a hull that's 8m long and 3.66 m wide.  It covers about 3% of the area we expect our projectile to land in.  I'll take my guided projectiles, thank you very much.

Quote
This is further helped by the railgun shell spending less time at lower altitude in "thicker" atmosphere where the deviations are higher then at higher altitudes ( for example wind or air/particle resistance ).
Flatter trajectory means this isn't true, either.

Quote
If you fire in space and your projectile travel at 50000km/s then the projectile spends less then a millisecond traveling through the thicker atmosphere compared to a battleship shell spending up to 30 seconds or more traveling meaning it's over 30,000 times more accurate...
You're moving the goalposts.  This particular discussion started with someone bringing up the Navy's railgun program.  Orbital fire support with that kind of velocity of weapons is a very different thing, and a somewhat better case for unguided projectiles.

Quote
Further orbit isn't as far away as you would think... The ISS orbits at 300-400km up compared to Battleship guns max range of 30-40km, that's just 10 times as far which compared to the other numbers involved here is nothing.
Can you please stop assuming things about what I think?

10
C# Aurora / Re: Replacing PDCs
« on: November 03, 2017, 09:21:05 AM »
Do you seriously think the US Navy would invest billions into railgun research to replace guided cruise missiles if the tech as you claim were useless as artillery and inaccurate?
1. For long-range land attack, they absolutely are looking at guided projectiles.  For other missions like point-defense, maybe not.  But there is no way you can use a weapon with the sort of range we're talking about without either guidance systems or a much larger damage radius than this provides.
2. Different kinds of targets require different damage profiles.  Against ships, planes, and missiles, unitary KE is great.  It's OK against bunkers, and terrible for infantry in the open.  This is a solvable problem, but it does compromise 'the projectiles are just chunks of metal'.
3. This isn't a cruise missile replacement.  They're looking at a range of 110 nm, which is an order of magnitude lower than Tomahawk.  It's a fire support weapon, not a strike weapon.  It also has roles in air and missile defense. 

11
C# Aurora / Re: Replacing PDCs
« on: November 03, 2017, 07:47:43 AM »
I'm not sure where you are getting that. A railgun round is just a rod of metal. All of the round's energy is kinetic. There is no explosive filler, no primer, no fuse, no guidance system (unless you want it), and you really don't even need a ballistic cap either.
No, for two reasons:
1. Simple metal rods are of limited use against most targets.  Maybe I kill one vehicle, but the rest of the rod's energy is expended digging a hole in the ground behind it.  That's fine in a tank, but not particularly good for artillery.  And tanks usually have some sort of explosive round, too.
2. I want to actually hit something at long range.  That means I need a guidance system, period. 
Railguns are interesting and powerful.  But they aren't a panacea, and they will require sophisticated ammo.

12
C# Aurora / Re: Replacing PDCs
« on: October 31, 2017, 07:32:52 AM »
If manoeuvre warfare is so effective that you can't have set fortifications that can't be moved when you are the defender and thus plonking your defenses right in the path the enemy's forces will take you need something that can pick up and go instantly because they are going to be flanked. And that means no towed guns.
I never said that.  I was pointing out (again) that people were misunderstanding what the 'static' classification meant. 

Quote
And with shells weighing in at 800 kilograms or more for the Iowa's 16 inch guns, and heavy naval artillery doesn't seem to come lighter than a few hundred kilograms. In theory you could create a sling and haul it with crewmen, so long as the stairs permit it anyway. Realistically though? If the hoists are dead so is the gun.
I'm pretty sure there's manual operation on the hoists, although as a practical matter, they'd be too slow to matter.  There's no way at all you could manhandle a shell up to the gun.  "Stairs" are near-vertical on a battleship, and the shells themselves are really heavy.

Quote
Strangely we may see a return of heavy gun artillery; if the railgun currently in development by the US Navy is developed to the point it's as good as promised it's effective range with a properly guided munition is hundreds of kilometers at a minimum. It'd be much cheaper per shot than a missile and not risk a human pilot.
Yes, but each round is going to be relatively expensive.  Not as much as a missile, but a lot more than a gun round.

13
C# Aurora / Re: Replacing PDCs
« on: October 30, 2017, 09:22:42 AM »
If that were true Static units wouldn't be a thing.
"Static" does not mean "dug in forever and ever".  Towed artillery counts as static.  If someone can come up with a better name, please do.

Quote
You are somewhat mistaken as to why heavy artillery for ships isn't the same as heavy artillery for land formations. Mostly, it boils down to ease of use and transport. A warship is generally designed around its weapon systems, and the magazines and loading systems can be trivially mechanized to support the gun; despite space being a premium on ships it's actually much more space and time efficient to have transport from magazines to the guns automated. That's at minimum 5 stories you need to lift those shells and propellant. And when you're talking heavy naval artillery of the era, every shell weighed tons. And I mean that literally.
The process is more manual than you'd think.  Everyone except Germany sized their powder bags to be hand-carried from the powder tanks to the guns.  Iowa's were 110 lb each, and there were 6 per shell.  And the largest naval shells were the 3200 lb 18" off the Yamatos.

Quote
And quite frankly, you don't need a 400mm or so gun to blow up most enemy positions. High explosive shells from 100-150mm artillery generally does that quite well.
What really killed off heavy artillery was the increased capability of aircraft and missiles.  A 16" shell is impressive, but it's very rare that you need so many that airplanes aren't a better and cheaper way of delivering the firepower.

14
C# Aurora / Re: Replacing PDCs
« on: October 26, 2017, 11:02:08 AM »
Not that you'd want to put static units with any others except as guards, in which case infantry will do fine, generally speaking. I'll repeat my worries about performance issues though.
Static isn't bunkers.  It's towed artillery and anti-tank guns and heavy SAM batteries and HQs which set up tents.  Basically anything which has to stop and deploy before going into action. 

15
C# Aurora / Re: Replacing PDCs
« on: October 20, 2017, 07:22:15 AM »
Submarine launched nukes are often considered the upper border of what would be a "tactical" nuke, so let's take one of the most common (W-76) in the US/UK arsenal. It has a fireball radius of 500 meters when detonating on the ground meaning the fireball covers an area of 0.79 km^2.
( Source: https://nuclearsecrecy.com/nukemap/ )
No, they aren't.  There isn't a precise boundary for "tactical" nuclear weapons (which have gone out of favor recently), but a W76 definitely isn't one.  Try something more like 10-20 kt.  SLBMs are strategic weapons, plain and simple.  And you're not just going to use fireballs to kill things, as that's inefficient. 

On the other hand Marski, if you are tossing ground detonation nukes around in such numbers that the fireballs overlap you can be fairly confident that whatever formation existed there does so no longer.
Is this a planet you want to keep?  Because if so, I'd recommend strongly against that.  Groundbursts are very dirty. 

Alright, since it seems I'm possibly the only one here who's actually gone through military service and is in reserve, I should explain couple of things for you folks.
I'm not military, but I've spent quite a bit of time studying nuclear weapons.  Also, please stop being condescending.

Quote
Nuclear weapons aren't magical. They operate on laws of physics like everything else. You don't drop them somewhere and have everything go dead with 100% certainty. Outside the imminent blastzone and lethal air pressure area, you can survive by simply hiding in a foxhole. This means vehicles too; dig in, wait for the blastwave to pass, get out, prepare for fallout unless your mission requires you to keep moving.
This, at least, is true.  Although it's not always the blast that kills you. 

Quote
Modern militaries across the globe have plans and doctrines on how to operate in a nuclear war. They differ and vary from country to country but they all have one thing in common; spread out. Companies have minimum distance of atleast ten kilometers from each other to reduce potential losses from TNW (Tactical Nuclear Weapon) being dropped. Motorized, Mechanized and Armored military formations are the most vulnerable and easiest to find and are on top of the priority list just below HQ's for TNW strike.
No.  10 km between companies is way too much.  Spreading out is good, but you can't fight like that, and most tactical weapons aren't that lethal.  Seriously, show me one tactical weapon with any kind of lethal radius of even 5 km.
And armored/mechanized formations are the most survivable on a nuclear battlefield, not the least.  AFVs are remarkably blast-resistant (hence enhanced-radiation weapons) and can carry NBC protection systems with them.

Quote
Infantry on the other hand are the least vulnerable (yeah, surprising), they can spread out as much as needed thus making it impossible to take out an entire battalion of infantry with just TNW's, infantry can take cover in absolutely anything or create some very fast. They aren't restricted by infrastructure and therefore can move anywhere and are difficult to detect from air or space.
And then are incapable of moving or, you know, actually doing anything useful.  Leg infantry has its uses, but when it has no supporting infrastructure, it's not going to stand up to someone who does.

Pages: [1] 2 3 ... 59