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Topics - Iranon

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Bureau of Ship Design / A formal look at various efficiencies
« on: November 03, 2016, 06:48:48 AM »
1) Let's assume we have a fixed tonnage budget for propulsion, i.e. engines and fuel, and we're interested in the trade-off between performance and fuel efficiency.

Let x be the proportion of fuel in our propulsion tonnage.
(1-x) is therefore our engine proportion. Keeping speed constant, this is proportionate to the inverse of our power multiplier.
Specific fuel consumption is proportionate to power multiplier ^2.5
Our range is therefore proportionate to x(1-x)^2.5
I find it more useful to map fuel use to speed at constant range than to range at constant speed: (x(1-x)^2.5)^0.4
Standardising for 1.0 as the highest possible speed, achieved at x=2/7, we get (x(1-x)^2.5)^0.4*1.4/(2/7)^0.4

Google calculator (just put the last function into a Google search field) gives us a nice graph with value pairs if we mouse over it.
This is ready for use with no further thought, I'm not aware of any hidden pitfalls.

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2) Now let's look at the effect of engine tonnage on cost and fuel efficiency. Speed is kept constant. We use a standard size for every single engine.
We simplify things a little and think of our ship as consisting of engine and payload, x being the proportion allocated to engines and (1-x) therefore being the payload.

Power is kept constant, so power multiplier is proportionate to 1/x.
Fuel consumption is therefore proportionate to (1/x)^2.5
Fuel efficiency is therefore proportionate to (1/x)^2.5/(1-x)
Standardising for 1 at the most efficient setup at x=0.714286, we get ((1/x)^2.5/(1-x))/8.11686

With power multiplier above 1.0, the engine cost is the same no matter the size. Cost efficiency of the propulsion plant is therefore 1/(1-x), the theoretical optimum being an infinitesimally small engine with infinite power multiplier.

With power multiplier below 1.0, cost of a single engine scales quadratically with power multiplier, so engine cost is proportionate to  1/x. Cost efficiency of the propulsion plant is therefore proportionate to (1/x)/(1-x). Standardised for 1 at our most cost-efficient setup, achieved at x=0,5, we get 1/(4x-4x^2)

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Putting ((1/x)^2.5)/(1-x))/8.11686 , 1/(1-x), 1/(4x-4x^2) into the Google search field gives you these graphs (fuel efficiency, cost efficency > 1.0, cost efficiency <1-0). For a useful overview we may want to zoom to have about 0.15 to 0.75 for x and 0.5 to 6 for f(x).

While I find this useful, this needs a little more caution than 1).
We count everything that isn't engine as payload. That includes bridge, engineering spaces, armour (can't do away with the first layer), and all sorts of other things we may not think of as mission tonnage. So a seemingly very fuel-efficient design with 70% engines may not carry a lot of stuff we actually care about, dramatically lowering practical efficiency.
What we count as overhead and what as mission tonnage isn't even fixed: for a general purpose warship armour may be mission tonnage, if a given speed in nebulae is a non-negotiable requirement some or all may be overhead.
Likewise, our ship will need to carry some fuel at the cost of payload, so our ship with the compact high-power engines may not be quite as cost-efficient as the graph implies. And if we'd need >40% of engine weight in fuel, corresponding to the 2/7 of propulsion tonnage as in 1), we probably dropped the ball.

Comments about correctness, clarity, usefulness or considerations I neglected are warmly appreciated.

EDIT: Assuming 5%/10% of ship size as overhead to be subtracted from the effective payload, one gets
((1/x)^2.5)/(0.95-x)/9.7130565 , 1/(0.95-x)*0.95, 1/x/(0.95-x)/4.43213
or
((1/x)^2.5)/(0.9-x)/11.7365 , 1/(0.9-x)*0.9, 1/x/(0.9-x)/4.93827

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Aurora Suggestions / More options for diplomacy?
« on: September 19, 2016, 04:56:40 AM »
I'm very satisfied with the shipbuilding, military, economic aspecs of the game... but diplomacy seems very limited.

I'd greatly appreciate if empires could make some territorial claims and try to have them recognised without full scale warfare. Like "this system/body is mine, no ships welcome" or "traders welcome, but keep your warships out", with the option to give it some force with a warning shot. There would be some diplomatic fallout, but not necessarily total war.

Military alliances, with effects on diplomatic standing depending on whether the player does something about a common foe.

If possible, also some expanded and international trade:
Inclusion of minerals. In case of unbalanced contracs, international or civilian trade: If demand contracts outstrip supply, supply by civilian or international partners for an appropriate wealth cost. If supply outstrips demand, the possibility of something being sold to civilians/international trade partners in a way similar to how civilian mining colonies work.
International trade would add very interesting scenarios, where outposts close to another empire's core might be economically dependent on foreign trade.

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Aurora Suggestions / Multiple engine types?
« on: June 24, 2016, 03:57:09 AM »
An interesting real-life trade-off that doesn't exist in Aurora is speed vs. fuel effiiciency during operations, we only get this at design time.
Some real life warships had a heterogenous propulsion plant: compact turbines for speed, efficient diesel engines or a cruising turbine with reduction gearing for efficiency at lower speeds. It could be interesting if we allowed this.

Option A: Only one engine type can power a ship (or tractor chain) at a time.
Instead of 4 engines of the same type, we could install 3 with the same total power and a crusing engine half as powerful as the original.
We double our fuel consumption at high speed, but reduce it by a factor of 5.7 at low speed (1/8 of maximum).
The drawback of this approach is that we'd need to take care not to introduce annoying micromanagement (e.g.: maintain distance to a ship that's faster than our cruising speed without wasting fuel)

Option B: Mix and match at will.
Here we'd probably go for something less extreme. 2 examples,

2 high-power engines at 1.2, 1 low-power engines at 0.6 compared to 3x 1.0.
20% speed and below - 28% fuel consumption
40% speed - 93% fuel consumption
60% speed - 114% of fuel consumption
80% speed - 125% of fuel consumption
Full speed - 132% of fuel consumption

1 high-power engine at 1.5, 2 low-power engines at 0.75 compared to 3x 1.0:
50% speed and below - 49% fuel consumption
60% speed - 87% fuel consumption
70% speed - 114% fuel consumption
80% speed - 134% fuel consumption
90% speed - 150% fuel consumption
Full speed - 162% fuel consumption


4
Mechanics / What causes ships to be destroyed?
« on: February 05, 2016, 02:13:21 PM »
I feel silly for asking such a basic question, and especially for not having asked it much sooner.
Most of the combat mechanics are available on the wiki, but I haven't been able to find out what actually causes a ship to give up the ghost and turn into a wreck.
Any ideas?

The answer could have interesting implications for ship design.

5
Mechanics / Grav Pulse Strength
« on: February 03, 2016, 11:03:11 AM »
The wiki states the GPS of active sensors should be range*resolution.

It's not, and at first glance seems to be proportional to range*resolution^0.5

Could someone enlighten me?

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Bureau of Ship Design / Share your little design tricks!
« on: January 25, 2016, 06:01:15 AM »
I thought it'd be neat to pool in on some little things that other players may have missed. I'll start off:

Subdivison. It's possible to make ships more resistant to damage by more extensive subdivison than the norm, as seen in many German designs during the world wars.
You can do this in Aurora by using smaller components that still have the same HTK, e.g. small engineering spaces or tiny fuel tanks. It's expensive compared to simply adding more armour, but doesn't add weight and helps against hits that would bypass armour, like shock damage or meson weapons.
I find this useful for very stressed designs that devote a high percentage to propulsion, with little room for mission tonnage or armour. Cool detail: Most relevant for fuel spaces as per the historical counterparts; WW1 arrangements incorporated coal bunkers into the protection scheme, WW2 designs used oil tanks as part of their torpedo protection system.

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Bureau of Ship Design / Does his work? 91 simultaneous salvos, on 1000t
« on: September 14, 2015, 07:11:55 PM »
I haven't been able to test this yet as I'm currently having some technical issues.
The theory: If I rely on missiles, I'm normally a big proponent of massive salvos from box launchers to oversaturate enemy anti-missile defence.
But there is something better than large salvos: An even larger number of missiles (on the same tonnage) in single salvos, arriving in the same increment.


Code: [Select]
Cheetah class Fast Attack Craft    1 000 tons     5 Crew     242 BP      TCS 20  TH 320  EM 0
16000 km/s     Armour 1-8     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 0     PPV 1
Maint Life 0 Years     MSP 0    AFR 200%    IFR 2.8%    1YR 23    5YR 343    Max Repair 21 MSP
Intended Deployment Time: 0.1 months    Spare Berths 5   
Magazine 91   

32 EP Magneto-plasma Drive (10)    Power 32    Fuel Use 336.02%    Signature 32    Exp 20%
Fuel Capacity 100 000 Litres    Range 5.4 billion km   (3 days at full power)

Size 1 Missile Launcher (1)    Missile Size 1    Rate of Fire 10
Missile Fire Control FC61-R80 (1)     Range 62.0m km    Resolution 80
ASM-1 Sloth (91)  Speed: 16 000 km/s   End: 72.1m    Range: 69.2m km   WH: 2    Size: 1    TH: 101/60/30

Missile to hit chances are vs targets moving at 3000 km/s, 5000 km/s and 10,000 km/s

This design is classed as a Military Vessel for maintenance purposes

I hope to achieve this by matching missile and platform speed - very slow missiles fired by a fast ship. This one may take 15 minutes to empty its magazines during an attack run (over a distance of 13.5m km, cutting significantly into its effective range)... but they should all arrive on target at the same time, in single missile salvos, rendering most defences comically ineffective.

There are probably many things wrong with the particulars of the design... but is the basic principle sound?

8
At reasonable tech levels, I prefer 10cm Railguns. With very little tech investment, they have a higher output per ton than endgame Gauss cannons.
Putting the considerable weight savings (bulky weapons, turret gear and fire controls) into engines partially solves the accuracy issues, among other benefits.

9
The Academy / Performance, recommended PC?
« on: March 06, 2014, 03:34:58 PM »
Sorry if this is the wrong place.

I currently play Aurora on a little ultrabook - i5-4200U (2x 1.6-2.5 Ghz),  Intel HD4400, 8GB RAM-1600, moderately fast SSD. It's playable, but not as fast as I would like.
Would I get better performance on my ancient desktop - Q6600 (4x 3.2 Ghz) , Nvidia Gefore 8800GTX, 4GB RAM-1200, 10000RPM hard drive?

I'd simply test it, but my desktop isn't currently running a compatible operating system.
Any performance tricks would also be very welcome.
Thank you for you time.

10
Bureau of Ship Design / Optimal Fuel:Engine ratio
« on: January 31, 2014, 05:18:24 AM »
Let's say we set a speed requirement and weight allowance for propulsion (i. e.  engines + fuel).

Let's standardise our weight allowance w on a weird but helpful unit: "the weight of a 1. 0-power engine needed to reach the design speed at the full design size".  Yes, it's ugly.  No, we won't have to standardise speed on "the airspeed of an unladen swallow".
Examples:
If we could reach our design speed with 1. 0 power engines but have nothing left over for fuel, w is 1
If power 1. 0 engines without fuel would require twice our weight allowance, w is 0. 5

The fuel we have available is (w-1/p), in the same awkward unit.  Because we know the efficiency modifier for a given power multiplier, our range at the desired speed and weight is proportional to (w-1/p)/p^2. 5

Now my hillbilly maths failed even harder at letting me go anywhere elegantly.  I just plugged in some values of w, differentiated the buggers with respect to p, and eyeballed the results for anything interesting.
Eureka: Maximum range at a given design speed and weight was always reached when fuel weight was 40% of engine weight.

All those long range missiles or independent (i. e.  neither tankers nor tankees) long range craft using more space for fuel than engine are wasteful.  Get close to a 2:5 ratio between fuel and engine, and adjust the power multiplier accordingly.
You may want erring slightly on the side of bigger engines: Achieving almost the same range on less fuel is an advantage, and if we're using a single big engine we get a further boost in efficiency.

11
New player here.  I'm still getting a little overwhelmed, but having a great time regardless.  Maybe some of the veterans around could tell me if this has any merit.
No self-powered warships above 500t.  Instead:

1.  Long-endurance fighters, with deployment times above 6 months.  High percentage of unarmed variants to let them operate independent of larger ships: Various sensors, Refuelling, possibly Maintenance and Boarding.
These won't try to be performance wonders, but to replace a small number of much larger ships. . .  with advantages in redundancy and sensor footprint.

2.  Tugboats.  Mostly commercial, maybe the occasional high-power variant.  The former will include basic sensors.

3.  Bases/Pods.  No engines, generous deployment times, doing one thing and one thing well.

Command: enough active sensors to light up a system.
Recon: largest amount of passive sensors crammed into the smallest hull, with no engine to give it away.  Sneaky.
Weapons: in both missile and gun versions, with supporting equipment.
Fuel, Arsenal, Maintenance pods.  The boring stuff.
Hangar: To support the otherwise independent fighter swarms, maybe also to field more stressed fighter designs.

Sizes will be standardised for the most part, with exceptions where practical -  e. g.  combined Hangar/Magazine pods to rearm box launchers.
The idea: A cumbersome but efficient way to get some big stuff where I need it, hopefully one that reduces support issues too.  The pods should work as solo bases at key locations.  The thing that worries me: If I slap a laser pod on a tugboat, and attempt to use it like an area defence cruiser. . .  is there something that is bound to go hilariously wrong?

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If this is the wrong place without example ship designs, I could provide some. . .  but for now I'm more concerned with concept than implementation.  Once I get there, I will have plenty of questions too.

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