Spaceships Questions: Guns

[SuedodeuS]

Originally Posted by Langy

Very slightly. The impulse imparted by a firing cannon is nowhere near enough to really move a ship all that far away.

Indeed. Consider - an SM +8 Spinal Battery fires 20 cm rounds. For a conventional gun, these weigh 400 lbs - a good deal of which is propellant. We'll assume that the propellant is weightless, however, meaning we are launching a 400 lb projectile at 1 mile/second. The ship firing the weapon weighs 1,000 tons, or 2,000,000 lbs. A force that will send 400 lbs at 1 mile/second will send 2,000,000 lbs at, what, .0002 miles/second? That's a little over 1 ft/s, which is basically negligible.

Now let's get ridiculous and consider an SM+8 ship that the Hull consists of nothing but batteries, all facing one direction. A Major Battery fires 16 cm rounds, Medium 14, Secondary 12, Tertiary 10. To send the most mass flying, we'll want all Tertiary Batteries. Each battery sends 3/4 ton flying (again, assuming the propellant is massless), meaning 18 such batteries is going to move 13.5 tons at 1 mile/second. That will move the ship back at .0135 miles/second, or 71.28 ft/s (23.76 yards/second). That's a noticeable jump at human scales, but it's still nearly negligible for much of spaceship combat - it burns up .0135 mps of delta-v to correct for. And this is assuming a ridiculous design and massless propellant.

[The Whiner Knight]

Thanks for the number crunching! I've never been good at that kind of math.

[jacobmuller]

Infinite range? have cannon rounds include a time limiter to detonate them if they fail to hit within a reasonable time. It can be switched off for bombardment of sessiles.

Recoil? Recoilless cannon? Venting system diverts gases for use as recoil compensation so even the negligible recoil is zeroed. Nice steampunk imagery too - all that smoke and flame.

[Frost]

Originally Posted by jacobmuller

Infinite range? have cannon rounds include a time limiter to detonate them if they fail to hit within a reasonable time. It can be switched off for bombardment of sessiles

I actualy think that this is pretty much reasonable. Given that although cannon rounds have a theoreticaly unlimited rainge and practicaly a very limmited rainge (the consensus so far) there exists a possibility of collateral dammage that more cautious planners may want to address.

[Langy]

Infinite range? have cannon rounds include a time limiter to detonate them if they fail to hit within a reasonable time. It can be switched off for bombardment of sessiles.

To be honest, it's not that big of a problem. There's already tons of junk soaring through space - and space is a big place.

[David Johnston2]

Originally Posted by Frost

I actualy think that this is pretty much reasonable. Given that although cannon rounds have a theoreticaly unlimited rainge and practicaly a very limmited rainge (the consensus so far) there exists a possibility of collateral dammage that more cautious planners may want to address.

Salty language:

http://www.youtube.com/watch?v=hLpgxry542M

[jacobmuller]

You're both right - it'd be really easy to include as a feature but highly unlikely to be included, until they actually manage to accidentally shoot something they shouldn't have, perhaps themselves.

I mean, what are the chances of hitting, and getting a one-shot kill, with a 22Rimfire at a range of 1 mile? But it has happened. The chances of cannon rounds hitting something they shouldn't are far less likely, but if you have a battle out by Jupiter and push 3,000 20mm cannon rounds in the direction of Earth's orbit, they might do something nasty, eventually.
Murphy's Rules of Combat: the most accurate incoming fire is friendly fire?

[Ulzgoroth]

Originally Posted by Langy

To be honest, it's not that big of a problem. There's already tons of junk soaring through space - and space is a big place.

It's true, but it's still a pretty likely feature. I think quite a lot of modern AA munitions have something similar to keep misses from falling back on unintended targets.

Of course, if you're playing in 'space is big', you're not too likely to have guns anyway, because their effective range is a joke.