Ship Design Philosophy

[AnotherDilbert]

The game designers will have to define what are sizable fractions of the speed of light.

Half? A third? A quarter?

I'm guessing Mongoose won't. Accelerating anything bigger than an atom to 0,1 c even in a spinal is pure magic...

A 1-kilogram mass accelerated to 1% the speed of light would deliver 1 Kiloton of destructive power to its target.

Quite, but 0,01 c is too slow to hit anything at 10 000 km (Medium range). 0,1 c might be fast enough. 10 times the speed means 100 times less mass for the same kinetic energy.

A minimal railgun spinal consumes 500 Power. That is about 5 GW, so in a round (360 s) it consumes 1,8 × 10¹² J (about 0,4 kt). With less than perfect 100% efficiency we might fire a pistol slug (10 g) at 0,1 c. The recoil would kick the firing ship apart.

A 18143.6948Kg (20 tons) mass would deliver 19 megatons of energy to its target.

Traveller is generally metric? 20 tons ≡ 20 000 kg.

 

[Condottiere]

Spaceships: Armaments and Mass of Chew Sets

Railguns
. Gabi
.. Thyssen Krupp Stahl AG
.. prototype
... increased size
.. ball bearing
... twenty-tonnes
.. TL 9
.. 4'200-tonnes
.. 1DD
.. medium range
.. 500 scotts
.. MCr 2'500.00

Mass Driver Bays
. Small
.. Thyssen Krupp Stahl AG
.. ball bearing
... two-tonnes
.. TL 8
.. 50-tonnes
.. 1DD
.. short range
.. 40 scotts
.. MCr 40.00

How fast do you think the the mass drivers accelerate their iron balls?

 

[AnotherDilbert]

If we take the numbers seriously the spinal will fire a 20 tonnes bullet using 500 Power for 360 s.

500 Power × 10 MW/Power × 360 s ≈ 2 000 000 MWs = 2 TJ max muzzle energy

e = mv²/2 ⇒ v = SQRT( 2e/m ) ≈ 14 km/s

If we shoot at a target at 10 000 km (medium range) the hang time of the round would be ~1000 s or three rounds. The target would be long gone by then.


t = 2d/v ≈ 14 ms is the time it takes to accelerate the round with constant acceleration.

The recoil would give the firing ship a speed of 20000 kg × 14000 m/s / 1 000 000 000 kg ≈ 0,28 m/s.
The acceleration on the ship would be 0,28 / 0,014 ≈ 20 m/s² or 2 G.

 

[wbnc]

The mass of the spinal mount and the mass of the ship would burn u a lot of the recoil from the gun itself. however, the mounting would be under massive stress loads to safely distribute all of that energy in a way that doesn't rip the gun loose from its mounts. a system that allows the gun to recoil inside the ship and slow down the transfer of energy from the gun to the vessel it's mounted on would also be a wise investment.

17t century gun mounts were fairly rigid and had no means to dissipate the recoil except direct transfer from the gun, to the mount to the ground. more modern systems have recoil mechanisms that slow the transfer greatly and dissipate the recoil by means other tan transferring it directly to the ground. it might be safe to say that a lot of the volume of a kinetic energy spinal mount would be taken up by its recoil system, and the reinforced structure needed to keep the weapon from tearing free of the ship.

 

[Condottiere]

Seems like an interesting way to make a getaway.

You turn around the ship and use the railgun as a sternchaser, the recoil pushing it faster ahead like an Orion drive.

 

[AnotherDilbert]

The mass of the spinal mount and the mass of the ship would burn u a lot of the recoil from the gun itself. however, the mounting would be under massive stress loads to safely distribute all of that energy in a way that doesn't rip the gun loose from its mounts. a system that allows the gun to recoil inside the ship and slow down the transfer of energy from the gun to the vessel it's mounted on would also be a wise investment.

Yes, note that I used a mass of 1 000 000 000 kg = 1 million tonnes for the ship, a reasonable mass for a 50 000 - 100 000 dT ship. A smaller ship would experience higher accelerations.

A shock absorbtion system would slow down the recoil, hence the felt forces, but it would still contain the same energy.

 

[AnotherDilbert]

Seems like an interesting way to make a getaway.

You turn around the ship and use the railgun as a sternchaser, the recoil pushing it faster ahead like an Orion drive.

The ship is given a reasonably good shove, but for a very short time. The ship is only accelerated for 0,014 s out of every 360 s round. The speed achieved is minuscule.

 

[Condottiere]

Spaceships: Armaments and If It Don't Reflect, You Must Deflect

Deflectors may actually not be some form of tractor/repulsor wide angle beam, it could actually be the projection of a gravitational field some distance from the hull, that warps the local spacetime sufficiently that the energy beam or missile changes direction.

 

[wbnc]

The mass of the spinal mount and the mass of the ship would burn u a lot of the recoil from the gun itself. however, the mounting would be under massive stress loads to safely distribute all of that energy in a way that doesn't rip the gun loose from its mounts. a system that allows the gun to recoil inside the ship and slow down the transfer of energy from the gun to the vessel it's mounted on would also be a wise investment.

Yes, note that I used a mass of 1 000 000 000 kg = 1 million tonnes for the ship, a reasonable mass for a 50 000 - 100 000 dT ship. A smaller ship would experience higher accelerations.

A shock absorbtion system would slow down the recoil, hence the felt forces, but it would still contain the same energy.

Very true. But most structures can better handle stresses that are spread out over a longer period. the ship would still have to use its drives to counter the acceleration forces

one idea that could work is using a counter projectile. accelerated in the opposite direction. Water, or sand....there would be some element of hazzard to vessels behind the firing vessel but that would dissipate as the counter projectile scatters.

 

[Condottiere]

Spaceships: Armaments and Enough Missiles to Blot Out the Sun

If we're going to follow the Honorable Art of War, we're going to need to be able to tinker with the missiles' propulsion system, that slow down the first couple of salvos sufficiently, that the later ones can catch up with them, so that they all can arrive at their targets at the same time.

You should be able to reprogramme faster missiles to fly slower and then go full speed into that kamikaze dive, together with the rest of its compatriots.

You could send in drones with them, to fire sandcutter rounds to neutralize those last ditch defences.

 

[Condottiere]

Spaceships: Armaments and Gunhouses

 

[Condottiere]

Dirtside: Ultimate Commuting

Apparently, there are gated communities designed around private airfield, and considering most spaceships are likely VTOL, you could have similarly concepted spaceports.

While passenger jetplanes cost vary across the board, apparently for fifty million bucks you can get a very comfortable large business variant; let's simplify the nineteen seventy five touchstone for Credit Imperiale exchange rate at five to one, so that a nine megacredit pinnace would have an asking price of about forty five million bucks.

A quick survey of modern jet engines for passenger planes is around two to twenty million bucks.

 

[wbnc]

I imagine that private small craft would be fairly common.I can see a lot of private spaceports being around on heavily populated worlds and even more corporate landing fields. In any well-developed system, there is more than just the planet , there are orbital facilities, mining operations off world facilities etc.. and being able to get to orbit, or another world without having to hitch a ride on an in system transport that might not match your timetable would be a huge asset.

on the purely recreational side being able to hop in your ships boat and take a nice vacation on mars, or head out and take a tour of the rings of Saturn would be a real attraction.covert cargo space into a couple of staterooms, and a nice recreation area and presto RV in Spaccceeeee.

 

[Condottiere]

My feeling is, recreational spaceships might actually be quite common, because they can be affordable to middle upper class.

 

[wbnc]

My feeling is, recreational spaceships might actually be quite common, because they can be affordable to middle upper class.

I agree.Considering how many pilots he Navy, marines, and scouts turn out every year I'd say there would be more than one or two who might decide they want to invest in a private launch or ships boat.

 

[AnotherDilbert]

The OTU is rather poor. The average GDP/capita of the Third Imperium is less than Cr 8000.

Spacecraft costing millions of credits are entirely out of reach of the middle classes.

 

[Condottiere]

Structuring modern social classes and castes is a little hard; let's say that middle upper includes those that have a billion bucks, which means two hundred million Cr/Imps in Traveller terms.

I think the lower uppers can lease pinnaces, and if the title is completely theirs, pass it on to an heir; maintenance is well within their means.

You may want to lobby the local regime for a loophole in inheritance tax.

 

[Condottiere]

Spaceships: Armaments and I Ain't Missiling You At All

It took a while until it dawned on me, and only because i was trying to figure out how to optimize loadouts on smallcraft.

A turreted missile rack supposedly holds twelve missiles, though it's not mentioned if that includes one in the launcher; twelve missiles weigh in at one tonne; three missile racks plus three launchers (unloaded), would equal to around three and a half tonnes, which would make the turret a sort of minor Tardis, not counting the workstation.

Then you exchange that hardpoint for three mounted fixtures, which don't take up any volume at all.

 

[Condottiere]

Spaceships: Armaments and Firm Foundations

Turrets are meant to be able to accommodate upto three, probably four generic weapon systems, which is why it's been standardized at a tonne.

A one weapon only turret can be constructed on a smaller volume, though you'd likely have to shrink the socket it would fit into, which is why for hardpoints no one bothers to, since you couldn't automatically plug and play, without adding some fillers, and then what's the point of trying to save volume?

With smallcraft, turrets remain stubbornly single, and if you compact the workstation a tad, it could weigh in between half a tonne and three quarters; half a tonne seems reasonable.

 

[Condottiere]

Starships: Engineering and Go Juice

It might be possible, that fuel, like petroleum, comes in many grades, optimized for certain usages and engines.