High-Burn Thruster
- Thread starter Nerhesi
- Start date
Nerhesi said:Lol - yes Chas , granted it's more of of thrust thing then stealth thing.
I think the distance bands will need a change if thrust stays as is. These 25G sdbs an space superiority fighters are going to force the issue.
Matt is aware but it's best to wait till everything in ship drives/speeds is finalized then determine if we need to Change the fact that ships can go from distant to adjacent in 2 turns
Are you sure of your rules interpretation there Nerhesi? The key paragraph seems to be
So getting out of Distant range band is 2 rounds at best possible speed Thrust 25 at TL15. It takes 50 thrust to close from Distant to Very Long, so even if you have 25 thrust, it is still going to take you 2 turns (and for many thrust drive builds 3). To move out of the Very Long range band you need thrust 25, which again for the absolute best possible build at TL25 is going to take a turn in itself. Because it takes all of your thrust 25 from moving out of Very Long range, you only end up in the Long range band. Then, and only then in the next round can you move from range band Long to any other inside that i.e. up to Adjacent.
That is at top TL15 speed at best it will take 4 turns to close from Distant to Adjacent.
Ah. Thank you Andrew. Alright, we'll see how this looks in the final rules. I liked the concept of folding away the benches for the boarding crew, which would only be a back up given the craft is gravity controlled anyway and then give them room to muster, but balance-wise it would be best if marines took the original 3 tons/6 soldiers.AndrewW said:
Chas said:
Sorry - I should clarify.
Very Long to Adjacent in 2 turns.
Yes Distant would take 2 more turns. I see the rule that stated you started at very long distance is removed, with a chance to start at Distant Range now. Still not sure if we want combat to go "Distant, Very Long, Long, Adjacent!!!"
Has anyone done the math to determine if high burn thrusters have enough specific impulse energy to move around some of these behemoths? It's one thing to hand-wave grav thrusters, cause you can give them any sort of output that you want. But rockets we do know. I would assume that these new rocket engines would burn a highly-efficient fuel, but that's still something we know pretty well these days.
So I'm wondering if you are tooling around in your custom 10kDton cruiser "that masses quite a bit due to it's collapsed armor plating) if regular rockets would be able to accelerate you to 9Gs? I don't claim to do any math outside of spreadsheets, so I'll let the experts do that math.
The other thing is that chemical thrusters seem like a giant step backwards in technology. It's not like it doesn't have real-world precedent, with some ships having both diesel engines for slow steady cruising and gas turbines for quick sprints. But chemical rockets just seem so inelegant in the 52nd century.
So I'm wondering if you are tooling around in your custom 10kDton cruiser "that masses quite a bit due to it's collapsed armor plating) if regular rockets would be able to accelerate you to 9Gs? I don't claim to do any math outside of spreadsheets, so I'll let the experts do that math.
The other thing is that chemical thrusters seem like a giant step backwards in technology. It's not like it doesn't have real-world precedent, with some ships having both diesel engines for slow steady cruising and gas turbines for quick sprints. But chemical rockets just seem so inelegant in the 52nd century.
phavoc said:
reaction drive doesn't have to be a chemical rocket if you don't like the idea. It could be a fusion torch, or some hybrid. A reaction drive system can be fairly advanced compared to the Von Braun kerosene and oxygen model...
In my universe I use a Plasma rocket/ramjet... basically fuel..water, or any easily pumped gas/liquid is introduced to a compact fusion bottle..this converts it to plasma, super-heating it and charging it...it's then channeled into an exhaust chamber where more fuel is added super heating it in the process.
to give extra oommmpfff the exhaust port has a charged grid that directs the gasses and creates a more effective control over exhaust gasses allowing for minor vectoring of the exhaust...
in atmosphere the crew can elect to open intakes and channel native atmosphere into the system, at which point the atmosphere itself becomes the reaction mass...thus the ramjet section of the system is engaged...since a fusion bottle is used to heat the reaction mass not actual combustion any sort of feul can be used...all it needs is a slight tweak to the turbo pumps to keep the fuel flow constant and at the required pressures...etc....( not something you do on the fly..more like an adjustment someone at a shipyard makes.)
I think phavoc the saving grace of rocket boosters in the 52nd century would be their ridiculous efficiency.
Edit: yeah wbnc said it well - what kind of chemical or chemical like reaction can be super advanced
Perhaps the fuel requirement formula needs to be multiplied by (Dton_shipSize / 200)
The drive size correctly scales with ship size, but fuel consumption doesn't (driving righ now, can't double check)
Edit: yeah wbnc said it well - what kind of chemical or chemical like reaction can be super advanced
Perhaps the fuel requirement formula needs to be multiplied by (Dton_shipSize / 200)
The drive size correctly scales with ship size, but fuel consumption doesn't (driving righ now, can't double check)
Nerhesi said:I think phavoc the saving grace of rocket boosters in the 52nd century would be their ridiculous efficiency.
Edit: yeah wbnc said it well - what kind of chemical or chemical like reaction can be super advanced
Perhaps the fuel requirement formula needs to be multiplied by (Dton_shipSize / 200)
The drive size correctly scales with ship size, but fuel consumption doesn't (driving righ now, can't double check)
problem is hen you get into fuel consumption/mass you have to know what system you ar using..the feul consumption /volume on a Hydrogen-Oxygen rocket is Higher than a single fuel plasma rocket like I described..or even a LOX-Kerosene rocket....TO "perfect" the fuel tonnage amounts for a reaction drive you'd actually have to specifically identify the system bieng used.
Yeah I totally messed that up - I somehow forgot that the basic "2.5% per Thrust per hour" means 2.5% of the total volume. Thats fine. That is the ratio we actually want - based on volume (as everything else is).
Ok - I think we've actually answered all the initial questions.
High Burn thruster is the same size/cost as the actual reaction drive engine. The only savings is the fuel cost because you will not be using it all the time.
And,
Yes - we will have some 20+ G small craft (at least capable of that for a couple of hours)
Ok - I think we've actually answered all the initial questions.
High Burn thruster is the same size/cost as the actual reaction drive engine. The only savings is the fuel cost because you will not be using it all the time.
And,
Yes - we will have some 20+ G small craft (at least capable of that for a couple of hours)
So do the inertial compensator nee grav plating, now also scale up to that level? I don't recall seeing anything along those lines. Should we assume that it's capable of doing so?
And the idea that it's not your great grand-dad's LOX-Kerosene rocket works better. Super-duper fusion torch drive seems much more palatable to me.
And the idea that it's not your great grand-dad's LOX-Kerosene rocket works better. Super-duper fusion torch drive seems much more palatable to me.
Glad I could helpphavoc said:
I would definitely say that you would need a gravity hull for a crew to sustain over one or two gees for any length of time. The hull and superstructure can be engineered to handle the forces dumped on it every time a ship maneuvers...but the crew would be in for a rough day if they had to pull more than a few gees for long.
From experience three gees is a lot to handle even in short spurts, you get tired fast, and just keeping you hands on the controls is tiring.
a compromise would be allowing for the crews acceleration couches to be fitted with GEE compensation..perhaps a GEE fitted bridge/cockpit.
Chas said:
As I was reviewing this Chas... There are a couple of things off.
Your rocket booster fuel seems to be half of what you need, it is supposed to be 2.5% per thrust per hour. So (2.5% of tonnage) x (16G) x (# of hours of usage)
Which means, 40% for 16G Thrust, per Hour. So thats 40% of 50 tons which is 20 tons. So tons of fuel x 2 = turns of thrust 16 the ship can do.
I still feel we need a way to differentiate the ability of relatively/comparitevly smaller craft strapping on boosters to reach breakneck speeds, versus 1000-ton SDBs trying to do the same.
Perhaps not touching the fuel usuage, but putting some limits on the max-total Gs for small craft, versus 100-500 tons, 500-2000, 2000+.. etc.. I dont know. Artifical yes... but I'm not sure we want 20G 3-million ton battleships right?
Perhaps not touching the fuel usuage, but putting some limits on the max-total Gs for small craft, versus 100-500 tons, 500-2000, 2000+.. etc.. I dont know. Artifical yes... but I'm not sure we want 20G 3-million ton battleships right?
Ugh. Early morning posting rushing to work, heh.
But where are you getting TL 16 from? The Thrust 16 reaction drive is a TL12 device per the table.
But where are you getting TL 16 from? The Thrust 16 reaction drive is a TL12 device per the table.
Code:
Reaction Drive Rating 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
% of Hull - 2% 4% 6% 8% 10% 12% 14% 16% 18% 20% 22% 24% 26% 28% 30% 32%
Reaction TL - 7 7 7 8 8 8 9 9 9 10 10 10 11 11 11 12
