Ship Design Philosophy

Discuss the Traveller RPG and its many settings
phavoc
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Re: Ship Design Philosophy

Postby phavoc » Mon Nov 11, 2013 3:58 pm

locarno24 wrote:True, but I can just about buy into a 50 dTon bay for Torpedoes. After all, you're 'flinging' 7.5 dTons per shot, in three 2.5 dTon blocks. Handling equipment for weapons like that taking up most of a decent-sized room is more or less believable.

A missile bay, by comparison, fires only 1 dTon's worth of ordnance, as you point out. I've no idea what the rest is for, either. If the 'missile launcher' was explicitely some sort of mass driver to impart an initial acceleration, fair enough, but then there would be/should be a difference between the turret missile racks and the missile bay tubes.
I'm not sure we have anyone on here who used to handle naval shells, especially the larger-caliber ones, but I'm former artillery, so I'm familiar with the concepts. I was MLRS, and if you know much about missiles, you know that MLRS has two types of rounds - the smaller 227mm round, there are six per pod. The larger ATACMS has one round per pod and is 610mm caliber. Actually, the ATACMS missile (at 4m) could roughly be considered similar to a Traveller Torpedo round (AFAIK no dimensions are out there for a torp round, just the displacement...anybody know any different?). It's a bit shorter than a Trav torp, but seems to fit the bill better. Size-wise, the old Honest John rocket is approximately the same size given for a torp (length wise at least, we don't know how wide one is).

Reloading is very easy and straightforward, and if you could actually create an external environment that was the same every time, you could do auto reloads with no more than twice the actual footprint of the vehicle (assuming you don't need to worry about where you dispose of your empty pods). People are only required because of the many variables you have being out in the field.

But I would think that torpedoes would be handled like naval shells, since we are talking about magazines to store them in. You would certainly need some tonnage for the equipment to have the ready rounds. But not the tonnage that is set aside. Since missile's don't bend very well, your machinery is going to probably store them horizontally on a track-like mechanism. The torps would be fed from the magazine to the launcher, and then loaded. Assuming you had an external turret "bay" the only time you might need to alter their plane would be to load them (though missiles all have bearing, so you should be able to launch vertically and let the torp's gyro's re-orient it towards the target.

Turret's store a single round onmount. Nothing in the description of missile or torpedo bay's says anything about onmount ammunition storage. The torps would be handled in the same way the missiles are. In some ways though, the missile possibly would require more tonnage, as you have to have 12 feed mechanisms to the three of the torpedo. And while the torpedo is physically larger, you can turn off gravity in the turret area so you only have to worry about mass - which the machinery should be able to easily handle without being overly large.

So, in summary, machinery the size of a room (and lets be generous and give 10Dtons (that's a pretty good room) is MORE than sufficient to handle weapons of that type. So the question still remains... what's the rest of the space used for? Since it's not ammo, those are some pretty generous maintenance access points!
Condottiere
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Re: Ship Design Philosophy

Postby Condottiere » Mon Nov 11, 2013 9:14 pm

I vaguely recall that sandcasters and missile had three rounds in the can, before you needed to reload them. Can't find any mention of that in Mongoose.

Loading the large calibre capital ship guns was an involved process, since you had to try to insulate the powder from any possible fires before sending up the load to the turrets. Since it came in bags, probably simpler than trying to manoeuvre a complete missile into a tube.
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Re: Ship Design Philosophy

Postby Somebody » Mon Nov 11, 2013 10:00 pm

Condottiere wrote:I vaguely recall that sandcasters and missile had three rounds in the can, before you needed to reload them. Can't find any mention of that in Mongoose.

Loading the large calibre capital ship guns was an involved process, since you had to try to insulate the powder from any possible fires before sending up the load to the turrets. Since it came in bags, probably simpler than trying to manoeuvre a complete missile into a tube.
The AT-8 Songster and it's follow ups are actually stored in two parts while in the auto-loader and only click together when fed into the gun/launcher. And AFAIK this is done automatically so maybe Traveller missiles are assembled "in the tube" (or launch cradle) and not in a magazin.

Some wester AA missiles needed their fins attached prior to going on the launcher so even manual assembly was done
phavoc
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Re: Ship Design Philosophy

Postby phavoc » Tue Nov 12, 2013 12:12 am

Condottiere wrote:I vaguely recall that sandcasters and missile had three rounds in the can, before you needed to reload them. Can't find any mention of that in Mongoose.

Loading the large calibre capital ship guns was an involved process, since you had to try to insulate the powder from any possible fires before sending up the load to the turrets. Since it came in bags, probably simpler than trying to manoeuvre a complete missile into a tube.
Artillery shells (larger ones at least) have the same issue that naval guns do - you have to add bags of powder after you add the shell. Take note of that order...it's rather important!

Navy shells came onboard in just the shell form, and the powder was brought aboard in cannisters. Here's a link to a good description of how they resupplied ammo on the larger surface combatants - http://www.worldaffairsboard.com/battle ... e-sea.html
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Re: Ship Design Philosophy

Postby Condottiere » Tue Nov 12, 2013 4:29 am

Checking up on a vague memory it seems the Germans used brass cartridge cases, supplemented by silk bags.

As with other German large-calibre naval rifles, these guns were designed by Krupp and featured sliding wedge breech blocks, which required brass cartridge cases for the propellant charges. Under optimal conditions, the rate of fire was one shot every 18 seconds, or three per minute. The gun turrets were electrically trained and the guns were hydraulically elevated. Gun elevation was controlled remotely. The turrets required each gun to return to 2.5° elevation for loading.
darue
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Re: Ship Design Philosophy

Postby darue » Tue Nov 12, 2013 11:38 am

hello o/

you know, in this tech/environment, I can't really "believe" in fighters. Why launch men in tiny little spaceships at all? A far more effective use of a ten ton fighter would be to mount a drone control in the cockpit and just have it run at 9g out a couple minutes and then back in at 9g for a couple minutes. Then ram the enemy. The kinetic energy would be massive, even with no warhead. Now optimize that. Armor around a pplant/Mdrive and a computer, fuel for an hour or two of max output. It comes in not on a direct course, so the enemy can't be sure which ship it's going to go for. starts erratic maneuvering inside medium range (or earlier), and goes for a target. Stealth'ed with reflec under the paint.

your best bet would be to run away from them. They're cheap as dirt. They're faster and more maneuverable than any piloted craft could be. They come in a variety of sizes. Some would even have their own point-defense lasers. The armor is the warhead.

You could even disguise them as space rocks and scatter them throughout a system decades in advance of hostilities.

Now at last we can have peace. :P
Condottiere
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Re: Ship Design Philosophy

Postby Condottiere » Tue Nov 12, 2013 12:05 pm

1. Actually, they've thought of that, which is why there are now limitations on kinetic kill missiles to prevent sticking large fusion rocket at one end, an armoured warhead on the other end, and letting it catch up with the target. The current version is a suicide drone with a nuclear pumped laser warhead, which you'll find in Traders and Gunboats.


2. I've gone over the Smallcraft gravitics drive, trying to figure out the best configuration for an economic insystem container carrier. The values are out of sync.

In theory, one ton of gravitics should be able to push 25.26 tons of displacement at one gee, which means sZ maxes out at 80 tons with six gee, and 4.8 gee at one hundred tons.

My maths may be wrong, so feel free to correct it.
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Re: Ship Design Philosophy

Postby darue » Tue Nov 12, 2013 12:27 pm

well, the math is doomed from the get go, the dTon really should be dropped. Just give us cubic meters and kilograms for components. Tech level and can then adjust the Volume, Mass and Cost for standardized Performance ratings of components directly. baseline at TL9 (for gravitic M drive), then as tech goes up, various things are possible, say at TL10 Volume is reduced 10%, at TL12 Mass goes down 10%, etc.

J drive performance is volume governed, while M drives performance should be governed by mass.
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Re: Ship Design Philosophy

Postby F33D » Tue Nov 12, 2013 1:45 pm

darue wrote:hello o/

you know, in this tech/environment, I can't really "believe" in fighters. Why launch men in tiny little spaceships at all? A far more effective use of a ten ton fighter would be to mount a drone control in the cockpit and just have it run at 9g out a couple minutes and then back in at 9g for a couple minutes. Then ram the enemy. The kinetic energy would be massive, even with no warhead. Now optimize that. Armor around a pplant/Mdrive and a computer, fuel for an hour or two of max output. It comes in not on a direct course, so the enemy can't be sure which ship it's going to go for. starts erratic maneuvering inside medium range (or earlier), and goes for a target. Stealth'ed with reflec under the paint.
That would probably be a good use for them. However, there is no stealth in space.
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Re: Ship Design Philosophy

Postby darue » Wed Nov 13, 2013 3:29 am

crossing over from another thread...

... I think that much acceleration (hundreds or more g) would overwhelm the inertial compensation. Your pilot would be jelly in a vac-suit. IIRC, there is no 'official' word on upper limits of artificial gravity, but I can't believe they intend it to be above the 9-15 range. Then again, maybe it HAS to be much higher... a 6g ship (or less) could probably pull curves that would generate a LOT of apparent g to the ship and contents. One way around that would be if the Mdrives were moving the entire reference frame so everything inside it's "bubble" is accelerated equally, but as written, it seems they just provide a reaction-less thrust.
Condottiere
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Re: Ship Design Philosophy

Postby Condottiere » Wed Nov 13, 2013 6:25 am

Acceleration is capped at six gees for ships seventy tons and over.

An acceleration tank plus one gee will allow pilots to operate more or less normally at eight gee.

There are manned fighters rated at twelve gee.

You'd have to source a medical opinion on how many gees a normal human can withstand on an acceleration couch for any prolonged period from six minutes and onwards.
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Re: Ship Design Philosophy

Postby locarno24 » Wed Nov 13, 2013 12:21 pm

Turret's store a single round onmount. Nothing in the description of missile or torpedo bay's says anything about onmount ammunition storage. The torps would be handled in the same way the missiles are. In some ways though, the missile possibly would require more tonnage, as you have to have 12 feed mechanisms to the three of the torpedo. And while the torpedo is physically larger, you can turn off gravity in the turret area so you only have to worry about mass - which the machinery should be able to easily handle without being overly large.
Torpedo Barbettes, bizzarrely, however, include two rounds internal storage. Go figure.
Understand that I'm not advocating violence.
I'm just saying that it's highly effective and I strongly recommend using it.
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Re: Ship Design Philosophy

Postby F33D » Wed Nov 13, 2013 3:42 pm

darue wrote:crossing over from another thread...

... I think that much acceleration (hundreds or more g) would overwhelm the inertial compensation. Your pilot would be jelly in a vac-suit. IIRC, there is no 'official' word on upper limits of artificial gravity, but I can't believe they intend it to be above the 9-15 range. Then again, maybe it HAS to be much higher... a 6g ship (or less) could probably pull curves that would generate a LOT of apparent g to the ship and contents. One way around that would be if the Mdrives were moving the entire reference frame so everything inside it's "bubble" is accelerated equally, but as written, it seems they just provide a reaction-less thrust.

It would be the limit of the G rating of the ship. Ships in space can't "pull curves that would generate a LOT of apparent g to the ship and contents". They can only pull to the G limit of their drive. So, launch tubes are pretty useless except for cinematic scenes to show at the local recruit office in order to weed out the uneducated rubes who are trying to become pilots...
Last edited by F33D on Wed Nov 13, 2013 6:53 pm, edited 1 time in total.
Condottiere
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Re: Ship Design Philosophy

Postby Condottiere » Wed Nov 13, 2013 6:12 pm

Barbettes are supposed to take up five tons, which assuming the torpedoes are at the standard 2.5 tons, makes that a rather tight fit. Also, not sure how you'd reload.
phavoc
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Re: Ship Design Philosophy

Postby phavoc » Wed Nov 13, 2013 6:57 pm

locarno24 wrote:Torpedo Barbettes, bizzarrely, however, include two rounds internal storage. Go figure.
Yes, another bizarre thing that should be added to the clean-up list. :)
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Re: Ship Design Philosophy

Postby darue » Wed Nov 13, 2013 10:04 pm

F33D wrote:
darue wrote:crossing over from another thread...

... I think that much acceleration (hundreds or more g) would overwhelm the inertial compensation. Your pilot would be jelly in a vac-suit. IIRC, there is no 'official' word on upper limits of artificial gravity, but I can't believe they intend it to be above the 9-15 range. Then again, maybe it HAS to be much higher... a 6g ship (or less) could probably pull curves that would generate a LOT of apparent g to the ship and contents. One way around that would be if the Mdrives were moving the entire reference frame so everything inside it's "bubble" is accelerated equally, but as written, it seems they just provide a reaction-less thrust.

It would be the limit of the G rating of the ship. Ships in space can't "pull curves that would generate a LOT of apparent g to the ship and contents". They can only pull to the G limit of their drive. So, launch tubes are pretty useless except for cinematic scenes to show at the local recruit office in order to weed out the uneducated rubes who are trying to become pilots...
eh, I'm not so sure about that can't. I don't mean real Gs but inertia in a change of vector, aka "g-forces" - which is determined by velocity. so a ship moving at say 5,000 km/sec turns 90deg off that vector and activates it's m-drive at say 6g, the inertial dampers will have a lot of work to do. Without them, the contents of the ship would feel more than 6g of g-forces, wouldn't they?

My physics is deeply rusty though, so I'm not sure about this.
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Re: Ship Design Philosophy

Postby darue » Wed Nov 13, 2013 10:10 pm

Condottiere wrote:The definitive guide to Traveller technology is probably Fire Fusion and Steel.
true :) I just got out my old paper copy and sure 'nuff it takes mass and tech level into proper consideration. I hate to say it but I'm now a little disappointed in the new high guard (and the missing things like electronics/mechanical shops, sick bays, communications systems.) OTOH, FF&S doesn't have any combat rules, and so no barrage attacks to speed up resolution. Someone needs to breed the two books together a bit.

Anyone given any thought to using FF&S designs in MgT?
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Re: Ship Design Philosophy

Postby F33D » Wed Nov 13, 2013 10:51 pm

darue wrote: eh, I'm not so sure about that can't. I don't mean real Gs but inertia in a change of vector, aka "g-forces" - which is determined by velocity. so a ship moving at say 5,000 km/sec turns 90deg off that vector and activates it's m-drive at say 6g, the inertial dampers will have a lot of work to do. Without them, the contents of the ship would feel more than 6g of g-forces, wouldn't they?

My physics is deeply rusty though, so I'm not sure about this.
Nope. They can't pull more than 6 Gs in that case. The ONLY reason aircraft can is due to aeronautical forces during change in direction. In space that doesn't apply. You aren't doing 90 degree turns as such. You are simply applying "thrust" from the drive is a different direction. There is no Star Wars type space maneuvering.

Find an old copy of Space Wars (originally from ~1964) and play it on your computer. It will give you a good feel for Newtonian movement in space.
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Re: Ship Design Philosophy

Postby darue » Wed Nov 13, 2013 11:44 pm

F33D wrote:
darue wrote: eh, I'm not so sure about that can't. I don't mean real Gs but inertia in a change of vector, aka "g-forces" - which is determined by velocity. so a ship moving at say 5,000 km/sec turns 90deg off that vector and activates it's m-drive at say 6g, the inertial dampers will have a lot of work to do. Without them, the contents of the ship would feel more than 6g of g-forces, wouldn't they?

My physics is deeply rusty though, so I'm not sure about this.
Nope. They can't pull more than 6 Gs in that case. The ONLY reason aircraft can is due to aeronautical forces during change in direction. In space that doesn't apply. You aren't doing 90 degree turns as such. You are simply applying "thrust" from the drive is a different direction. There is no Star Wars type space maneuvering.

Find an old copy of Space Wars (originally from ~1964) and play it on your computer. It will give you a good feel for Newtonian movement in space.
ok, (I did space war on the atari 2600) but if you change attitude while under acceleration (as is likely during evasive maneuvering)? At this point I'm thinking about what the crew would feel in the absence of grav-plating/inertial dampening.

I think a key issue here is: Do M-drives produce Coordinate Acceleration or Proper Acceleration.

http://en.wikipedia.org/wiki/G-force

but I'm leaning toward "you're right" in that a 6g m-drive in deep space could only ever subject crew to 6g g-forces, though the direction of that felt force is not necessarily "backward"

grav plates must do some fancy and rapid alteration of their field vectors, so it seems likely some small sense of motion is still felt, though it may be no worse than you feel in a typical car turning.
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Re: Ship Design Philosophy

Postby F33D » Thu Nov 14, 2013 12:35 am

darue wrote:
I think a key issue here is: Do M-drives produce Coordinate Acceleration or Proper Acceleration.

http://en.wikipedia.org/wiki/G-force
The actual issue is Newton's 2nd Law of motion.

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