Space Warships : What if bigger ships are faster?

[ModZero]

You don't need a turning rate, you need full size engines on your sides, and potentially much lower twr for "proper" acceleration. And if you get close enough, just explode yourself throwing out lots of directional shrapnel, interesting radiation and anything else you can think about, you're going to die anyway. 

[Elukka]

Depending on the type of your main engine it might well be a significant portion of ship mass. I'm assuming something beefy if multi-light second ranges are involved. If you just duplicated the main engine all over it'd get very heavy very fast, and now you have radiation blasting you from all directions, ("beefy" pretty much equals "some species of nuclear") and your structure needs to be able to take the acceleration from all directions.

You might have a big main engine and smaller, much lower power yet high thrust maneuvering engines on the sides, which seems feasible enough. They too would involve a mass penalty due to structural concerns and the extra propellant they'd eat. If you don't expect to need to jink for prolonged periods it might be fine. Of course, if you do this you do also get a fast turning rate out of the deal so you're free to use your main engine in addition.

[ModZero]

Radiation isn't a concern because it's unreasonable to stick meatbags into these anyway, and the electronics won't have to survive long enough for this to be an issue. While you need a healthy approach speed, you don't need to accelerate along the course as much as you need to be able to remain unpredictable on approach, and a "main engine + RCS" setup tend to commit you to relatively predictable trajectories compared to "just fire all the stuff randomly with thrusts that would convert a meatbag into Chipotle. And if someone sent a meatbag at you, rejoice, as this limits their manoeuvrability and lets you convert it into a fry with a boring gamma ray.

[Bill Phil]

10 hours ago, ModZero said:

You don't need a turning rate, you need full size engines on your sides, and potentially much lower twr for "proper" acceleration. And if you get close enough, just explode yourself throwing out lots of directional shrapnel, interesting radiation and anything else you can think about, you're going to die anyway. 

Except engines are exensive. 

Anyways, if you go with engines on all axes mode, you'll still have course changing time.

[Elukka]

11 hours ago, ModZero said:

Radiation isn't a concern because it's unreasonable to stick meatbags into these anyway, and the electronics won't have to survive long enough for this to be an issue. While you need a healthy approach speed, you don't need to accelerate along the course as much as you need to be able to remain unpredictable on approach, and a "main engine + RCS" setup tend to commit you to relatively predictable trajectories compared to "just fire all the stuff randomly with thrusts that would convert a meatbag into Chipotle. And if someone sent a meatbag at you, rejoice, as this limits their manoeuvrability and lets you convert it into a fry with a boring gamma ray.

I think this discussion is very dependent on setting assumptions. I'm not saying you're wrong, but we're running into very different conclusions due to different starting assumptions. So I'm just gonna give you a load of mine.

My vision of an engine that's both high isp and high thrust enough for the job is something fairly gigantic, like an Orion drive or one of its more advanced derivatives. Unless you can drive x-ray or gamma ray lasers its laser optics will likewise need to be huge; tens to hundreds of meters in diameter for a multi-light second range. It needs a nuclear reactor and a big laser engine (and the associated thermal control systems) to give it the power to actually hurt similarly sized ships. It'll be a large, complex and expensive machine, and it might have a small crew just to keep it running. More battleship than expendable drone.

With these assumptions there would actually be room for a craft like you describe: A maneuverable optical drone that's shot off ahead of the ship carrying the laser. The ship hangs back while the drone moves into weapons range and performs evasive maneuvers. It'd basically be a giant focusing optic with a bundle of engines, that catches the ship's laser and focuses it to a killing point. This extends the laser's range and enables the ship to stay out of harm's way.

Here's a warship design I've been working on for my game/fiction setting: http://i.imgur.com/ivz9ReL.png For scale, it's 830 meters long and masses about three million tonnes. (of which more than half is propellant) This one lacks a laser but it's similar in design to the ones that carry one.

Edited January 8, 2016 by Elukka

[cantab]

My two cents: For manoeuvrability, either clustered main engines or thrust vectoring. Either approach avoids the dead-weight of engines in all directions and the shortcomings of relying on secondary thrusters for turning. The cluster works better with a short wide ship, something like a flying saucer, while the thrust vectoring works better with a long skinny ship

[T'Flok]

My mind is something of an anomaly as I think of things that haven't even been invented yet on this planet. Such as propulsion that doesn't need thrusters/exhausts, has mass reducing device, a warp drive, some type of forcefield technology around the ship and multi-layered armor hull as a physical defence.

Yeah go ahead and laugh, yuck it all up. In about 10,000 or so years we'll see who's laughing. I'm just frelling tired of this primitive world and being stuck on it so excuse me if my fuse gets short.

Edited January 8, 2016 by T'Flok