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Missile and Ship Speeds

F

FrostJaeger

Banned Member
Seeing as how there's a standard for starship speeds in space, would it be possible @Wes (don't know who else to tag, really) to have the same for starship (/PA/starfighter/etc.) speeds in the atmosphere?

On that same note, has there been any progress towards making speed guidelines for missiles as mentioned here?

Not trying to be rude or anything, of course - I'm just, uh, curious [plotting intensifies]
 
For the purposes of this discussion and potential rule-making, we're talking about speed in a Yamatai/Nepleslia-grade atmosphere, right?
 
I think this would depend a lot more on the shape of the ship than its propulsion technology, unless deflector shields can be used to make something more aerodynamic. If that's not the case, the top speed might apply mostly to aerospace fighters and really slick warships, while bulkier craft don't stand a chance of approaching it, due to the sound barrier.
 
We've ... pretty much handwaved it. Shields are the great equalizer, but on Yamatai we had a kind of speed limit for aerospacy flight. Unofficial.
 
Bear in mind that most ships can likely achieve escape velocity to leave the gravity well of their homeworld.

So, technically, escape velocity is the very least they can achieve.
 
There's no minimum air speed associated with being able to reach escape velocity, since ships can reach escape velocity after leaving the atmosphere. In theory, a ship with a low enough density could leave the atmosphere by floating upward like a balloon, though the wind would probably blow it away on the way up.

A ship with a low air speed isn't limited from reaching space, so long as it can at least counter the planet's gravity and fly upward for long enough. There's no need to worry about a ship not being able to fly through air fast enough to leave the atmosphere, unless it's at risk of falling back down before it achieves that altitude.

A ship with a reactionless drive isn't constrained by escape velocity at all, since it doesn't have to drift out of the gravity well, and can keep flying away until the speed needed to escape becomes negligible. Escape velocity on Earth is measured in kilometers per second, so it's not very safe or practical to reach it near the surface.

Achieving it at the surface wouldn't let a ship break orbit without continuing to accelerate, either... air resistance would slow it down. The ships in this setting, though, if they can go that fast, would be able to leave the atmosphere in mere seconds, which could be helpful if they need to scramble to orbital defense the moment something is detected a few light minutes away, in the same system.

If ships went at these speeds all the time, starports would be noisy beyond belief, and their workers would probably need to stay underground, behind walls, for their own protection. They'd also have to be careful to keep birds out of flight paths, because colliding with a bird at over ten kilometers per second would be worse than getting shot by a tank cannon.
 
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Dang, I used to be good at math. This took way longer than I care to admit:

We could attach the speed of missiles to the High/Med/Low values of ships and end up with something like this:

Ship Speed Based
Fast Missile: .675c
Med Missile: .6c
Slow Missile: .525c​

A few assumptions are made here. Generally a 'turn' is about 10 seconds, and that you can't hit your target further than 3 light seconds out. Assuming your hero-ship takes evasive action and flies directly away from the missile, it will be within shooting range for less than one turn before it hits the ship, giving you one round of shooting.

A Fast missile will hit a Fast ship within one turn, a med missile will hit a medium ship within one turn, a slow missile will hit a slow ship within one turn.

This doesn't scale too well though. As a slow or Medium missile will still hit a fast ship, just within 2 turns of shooting instead of 1.


The other option would be to base missile speed on game play.

Game Play Based
Fast Missile: .675c
Med Missile: .475c
Slow Missile: >.2c
​
Fast missiles still always hit their target with one turn of defensive shooting.

A Medium missile traveling at .475c will hit a target that isn't running within one round. If the ship turns and runs it will take 9 rounds of shooting.

A slow missile will take 2 rounds of shooting to reach a target that isn't running, and will never catch a target if it runs.

We could easily setup a missile standard speed page just like the starship standard page and later on I'm sure we could add in rules for how many of what type of missiles you can carry. It makes sense that fast missiles would need big, powerful engines and that you could easily fit 10-20 slow missiles in place of one fast missile. Of course that extra fluff doesn't need to be added in now, we can always do that later.

(In terms of gameplay, if you remember 40k 3rd edition, there were AP1 weapons and AP2 weapons, both of which ignored all armor but AP1 existed just to show that the weapon was better than the AP2 weapon for fluff reasons. Games Workshop didn't get around to adding in rules for AP1 until 4th ed. Just like here, we should probably keep in mind how we're going to use these rules in the future and try to plan accordingly.)
 
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