Tech Tree Revision Comments

[Kaiser Kirk]

Formula Fun
In which I try to apply what's there.
Perhaps my math skills are too antiquated.

Technology cost is modified as follows:
c = cost
b = Base cost
y = difference between current sim year and year listed with technology in tree with earlier than the listed year as negative and later being positive

If y < 0 : c = MAX(0.05 * y, 0.25)
If y ≥ 0 : c = e(0.321888 * y)

Please use the calculator below to get tech costs.

note : "e" is undefined

For a 1908 tech researched in 1910
So Y = difference between current sim year (1910) and year listed (1908) .  So Y = 1910-1908= 2
The technology in the tree is earlier than the listed year, so Y=  -2.

C = MAX(0.05*-2, 0.25)
I don't understand this formula

Guessing MAX means the larger of.
In this case 0.05*-2 is : -0.1, so the cost is 0.25 ?

So for a 1910 tech researched in 1910
So Y = difference between current sim year (1910) and year listed (1910) .  So Y = 1910-1910 = 0

C = e(0.321888*y).
If Y=0, then
So C = e * (0.32188*0)
Since anything multiplied by 0 is 0..
C = 0
free techs !

So for a 1913 tech researched in 1910
Y = 3
C = e(0.321888*3).
C=e(.96564)
So, what "e" is becomes relevant.

[snip]

e is this badboy. Dont have the time to reply in full, but the calculator looks good now. What changed was that we went from "Pay to you get it" to "Fixed cost" and never listed that cost.

[Kaiser Kirk]

Ah, Logs.
Yeah, haven't touched that in decades.
Oddly, I do use a little stats and rarely even linear regressions.
Tomorrow I may even use the tangent function.
oooh.

But yeah, totally oblivious to the idea it was some math constant.

[Kaiser Kirk]

Naval Artillery Questions

Looking ahead at my next generation of guns :

1) When I get there, the 1910 Naval Tech allows a 255mm/ 55 caliber gun with a ME of 2500. 
While MV and barrel length are linked, as a longer barrel allows complete combustion of the propellants- but that was why guns went from 30-35cal to 40-45cal.
After a certain point, the way to make a shell go faster is add more propellant.
Presumably the limiting factor is the metallurgy to take the chamber pressure of that charge.

According to SS, a 55 caliber shell is 247.75kg.
I've been rounding the .xx part, so 248kg.

According to Logi's Ballistics tool,

a 255mm shell weighing 248kg moving at 921m/s has a ME of 2496.

However, that is well in the "stripping the barrel" range of muzzle velocities, not to mention unstable rounds.

Personally I don't want to push the round past ... say 850m/s.
That takes a ME of 2126.

Question : So, since 2126ME is 85% of 2500ME, does that mean the guns can be 85% of 55, i.e. a 255mm 46caliber gun ?

2) In the above gun, a 46 caliber round is normally 236.69, or 237kg.  However the max weight for the tech is 248kg.

Question : The max shell weight for that bore is the one we get to use, correct?
I.e. if I have 1910 tech, allowing 255mm/55ca,  I get to use that shell weight even if I'm only building a 45 caliber gun ?

[snip]

That is honestly something I have never thought about before. I thought that the ME part of the table had depreciated at some point, I just never removed the text because formatting that table is a complete PITA.

[Kaiser Kirk]

That is honestly something I have never thought about before. I thought that the ME part of the table had depreciated at some point, I just never removed the text because formatting that table is a complete PITA.

That's kinda funny.  For the Dutch in Wesworld, the Bavarians and Italians here, I custom made guns. I figured regardless of what others used, at least my navies would be internally consistent.
Usually I used "Biggun.exe" but I can't get it to work with Win7....plus Logi's tool meant I didn't need to take time to figure out how to make BigGun work.

Formerly, with Bavaria and Italy the increased ME meant I could hold at my desired muzzle velocity, but raise shell weight - which was ahistoric and we've fixed now. That seemed better than raising the MV. For example the British 12"/50cal fired at 850m/s but had a barrel life of 150 rounds and tremendous dispersion.... not worth it for me.

Anyhow, for me it was a combination of giving me consistency on armor and weapon design schemes. For Persia I made a excel sheet of potential weapons and then tested them in Logi's Ballistic - which I calibrated with Navweaps data for AP (not APC) rounds.

This is why the Gilgamesh Class, designed when battle ranges were still 3,000m, has that exceedingly thick belt to make her proof against own weapons at that short range. The Enki, designed the year after when the effects of the new gunnery systems would be more evident, are armored for the 6,000m range.

Anyhow, I'm using 825-830m/s as the upper limit for my desired large guns, but I've hit that already with many of my 40 and 45 caliber guns. For something like a 255mm gun, I need 2003ME to fire a 248kg shell at 825m/s, which you get with the 1900 tech.  I've also scaled ME by cross section area for smaller guns, and they peak early also.


Hmm, I type too much.

[snip]

I normally just look at historic guns and modify shell weight from there, hence why its something I've never really done.

[Kaiser Kirk]

I normally just look at historic guns and modify shell weight from there, hence why its something I've never really done.

I did that originally, but I had problems with the treaties meant the powers kinda standardized weapons, while I wanted to explore ahistoric choices.
For example, the heaviest hand loaded round is pretty much the UK's 7.5" on Hawkins, which is slightly larger than the US 7" and smaller than the French 194mmm. Supposedly the 8" gun was a Japanese demand as they had problems handloading shells this size. As a result, modern versions of weapon range doesn't exist to compare to. Meanwhile SS thinks the top of the QF range is 165mm, so that's my top QF gun....but there is no historic parallel, closest is the German 6.75", which went away. Likewise the 9-10" range, which is handy, went away historically.
Then there's things like my desire to top out at 17" or 20" - neither with historic parallels :) 


So I got into designing my own guns. One light battleship I made I specifically played with the parameters so that the shell would drop heavily beyond 20,000 yards, and be a very good deck hitter- accepting the accuracy issues- so I could field a viable small battleship for island and escort duty :)

Anyhow here in Nav7 it's decidedly influenced my ships. The new Tiamat class using the 1905 gun tech (gained 1907, guns done designing 1909..), I redesigned the early ship to upgun the  weapons from 360L40 up to 365L40 specifically because the 360mm fires at 840m/s and the 365mm fires at 824m/s and has much better penetration at combat ranges. 
Because light shells bleed velocity faster, the 360L40 and a 345L45 at 10,000m have virtually the same performance. But the 365mm "costs" more in tonnage, but with a return on performance.

Anyhow, if you are curious and if you burrow into my encyclopedia, you'll see my naval artillery section has a summary of what I came up with. The stats will change with Capped shells, as I'll recalibrate Logi's tool for newer weapons.  https://www.navalism.org/index.php/topic,7037.0.html

To answer my questions.... I'm getting the hint you don't care that much, so I'll feel free to make my next 1905 tech 10" class gun...nominally a 10/55 gun at 912m/s into a 10/46 with a 850m/s velocity.

[snip]

To sum it up, as far as I am concerned two things here are true.

1) Whatever options exist in the gun table (even things I thought were depreciated), they are to be considered the maximum upper bound.

2) When good justification and research exist, Im likely to be happy.

[Kaiser Kirk]

To sum it up, as far as I am concerned two things here are true.

1) Whatever options exist in the gun table (even things I thought were depreciated), they are to be considered the maximum upper bound.

2) When good justification and research exist, Im likely to be happy.

Well I was typing up stuff offline.
I agree with your positions, what I expect :)

Anyhow, now to post more of my endless blathering about minutia nobody cares about !  ... but I find weirdly interesting !

More fun with ME :

A 1910 tech gun will be available in 1914, when 1912 fire control is available, so say 10% hits at a range of 14km.

If you build the max bore for the range, it's not always the best answer.  For example, building a 16.5" gun is likely better than a 18" gun, because you still get the 6500ME, but it gives you a better MV.

1910 Tech, 18" / 40cal Gun : 6500 ME, SS default shell 1268kg, gun 138t

1910 Tech 16" / 45 cal gun : 5800 ME, SS default shell 937kg, gun 115t

1910 Tech 14"/50 cal gun : 5100 ME, SS default shell 659kg , gun 90t

1910 Tech 12"/50 cal (same as 1905 tec) : 3600ME, SS default shell 415kg, gun 56t

1910 tech 10"/55 cal : 2500 ME, SS Default shell 245kg. gun 37t

While a 1910 tech 16.5"/40cal with 6500ME, has a default 976kg shell and wt 106

So what's the Penetration at 14,000m ?
Well using my adjustments to Logi's tool based on some Navweaps comparisons, adding 20% to the belt pen for APC shells.

18"/40, 1268kg @ 657m/s  : 26seconds flight, descent at 15deg, Belt : 260mm, Deck 109mm (!!)
Great deck pen, but this shell is not going to be terribly accurate as it's really starting to plunge.

While 5 seconds may seem like little, that's a 25% longer flight time than the 12-14" weapons, during which time a ship at 18knots moves 147 feet - about 1/3rd of hull length of say HMS Erin, and more than the entire beam.

16"/45, 937kg @ 722m/s :  24seconds flight, descent 13deg, Belt :281mm, deck 86mm.
Better mix, but since under..18km?...you're still looking at more belt than deck, and plunging shots are much harder to land, still not a great trade off.

14"/50, 659kg @ 807m/s : 21 seconds flight, descent 10deg, Belt 304mm, deck 64mm

12"/50, 415kg @ 855m/s : 21 sec flight, descent 10deg, belt 255mm, deck 52mm
Obviously, the OTL British 12"/50 at 850m/s was the reference point, and it had been replaced by the 13.5" at this point.

10"/55, 245kg @ 927m/s : 20sec flight, descent 10deg, belt 217mm, deck 40mm
The 927m/s is way to high, barrel life would be under 100 rounds. Even so, the light shell means it just can't carry the kinetic energy to matter in a capital ship fight. It would however have ventilated an Invinvible class or anything smaller than a capital ship, while 10" guns were faster ROF than 12".
At 830m/s the barrel life climbs dramatially, while penetration should be about 174/50, perfect for cruiser killing.  Hence my interest in a 10"/46.  Heck I may rearm my old 1894 coast defense ships with something like that to extend their usefulness.

Then that hybrid 16.5" / 40 : 976kg @ 749m/s :23sec flight, 12deg angle, Belt 293mm, deck 78mm.
Better/faster/lighter than the 18"/40, comparable to the 16"/45, but weighs more, fires slower.

Makes sense that the US used 14"/50s, while the Brits fielded a 15"/42 (get the ME of the 16"/45").