FFW doing it my way

[MarcusIII]

That is it exactly. Aerofins don’t make the hull more aerodynamic; they provide active control authority that prevents structural flutter and thermal overstress at high atmospheric speeds.

At those TL's embedded attitude thrust nozzles would be employed for that, not fins that actually slow the craft. The rules need to be reviewed by someone with at least some aeronautic knowledge.

 

[ProfGrizzlyJon]

At those TL's embedded attitude thrust nozzles would be employed for that, not fins that actually slow the craft. The rules need to be reviewed by someone with at least some aeronautic knowledge.

Would you prefer if we called them "adaptive aeronautical control surfaces" or "Atmospheric Manoeuvre Enhancement"? It doesn't change the game mechanics. Aerofins is simple enough for the concept without breaking out Reynolds Numbers.

No need to start the argumentum ad hominem shenanigans; this is still a simplified game that revolves around 6-sided dice.

 

[MarcusIII]

Would you prefer if we called them "adaptive aeronautical control surfaces"

No, I prefer that they are described correctly. Did you have to be sarcastic for no f'ing reason? <ignored>

 

[ProfGrizzlyJon]

Did you have to be sarcastic for no f'ing reason? <ignored>

Yes, the sarcasm was intentional. Your comment about needing someone with "real aeronautic knowledge" wasn’t exactly made in a spirit of expertise or clarity, so I treated it accordingly. If you want to talk mechanics seriously, great. If not, don't waste more time on it.

 

[Vormaerin]

"At those TLs" no one currently alive has any idea what will work or not work, because no one knows what the technological constraints will be. Sure the laws of aerodynamics will be the same. But we have no idea what kinds of engines, control systems, or hull technologies will actually exist. Everything about TL 9+ is completely made up with varying degrees of scientific plausibility.

And, at least as importantly, 99% of the people who play the game will not even know the technologies that exist right now. "Optional thingie that helps with atmospheric flight which costs x" is what's needed, along with a term that conveys what the thing is without needing a whole paragraph.

 

[phavoc]

Going by Traveller travel mechanics, you could have a slow ascent rocket, since the formula is acceleration minus local gravity field, then excess acceleration divided by twice local gravity field to arrive at number of six minute rounds to reach orbit.

Terran norm at three gees means you're in orbit in six minutes.

Half that, at one and a half gees, twenty four minutes.

Assuming two and a half percent fuel consumption, per hour, that's half a percent.

I guess our reactionary rockets are really super efficient, relatively.

One of Elon's starship rocket burns 11k lbs of propellant per second, or 660,000 lbs/min. Not sure where you are getting your fuel calculations from.

Rockets are notoriously inefficient based upon how much fuel they burn to loft their payload. But if you need to get to orbit it really doesn't matter how efficient they are, just as long as they get you there. Reusable rockets means the most expensive parts, the engines and turbopumps are reused. LOX and Lhyd, or methane or kerosene) are relatively cheap.

 

[phavoc]

Would you prefer if we called them "adaptive aeronautical control surfaces" or "Atmospheric Manoeuvre Enhancement"? It doesn't change the game mechanics. Aerofins is simple enough for the concept without breaking out Reynolds Numbers.

No need to start the argumentum ad hominem shenanigans; this is still a simplified game that revolves around 6-sided dice.

With grav tech there's really not a reason to put such things a starship. Aerofins and other types of things would be better suited for vehicles intended to be atmospheric-only (or primarily).

An interesting aside - people kind of expect new aircraft to have winglets, but depending on your wing geometry they can be contraindicated. Aerospace design is hella complicated, and you are right that its not really necessary to fully model the game using real-world mathematics. What would be nice is if the rules acknowledged such things and built it into the mechanics without all the math. Math.... bad.

Like Getty Lee said, it's much easier to roll the bones.

 

[Condottiere]

It's Traveller game mechanics.

 

[ProfGrizzlyJon]

It's Traveller game mechanics.

One of Elon's starship rocket burns 11k lbs of propellant per second, or 660,000 lbs/min. Not sure where you are getting your fuel calculations from.

Rockets are notoriously inefficient based upon how much fuel they burn to loft their payload. But if you need to get to orbit it really doesn't matter how efficient they are, just as long as they get you there. Reusable rockets means the most expensive parts, the engines and turbopumps are reused. LOX and Lhyd, or methane or kerosene) are relatively cheap.

A big TL-8 chemical R-Drive —one that chews through ~11,000 lb of propellant per second—effectively behaves like a ~1.8G constant-acceleration vehicle when you look at how fast it actually builds Δv. Modern heavy rockets reach orbit in about 8.5–9 minutes, which works out to roughly that net acceleration once you fold in the full 9.4 km/s LEO budget.

Compare that to Traveller drives:

• 1G → ~16 minutes to reach 9.4 km/s
• 2G → ~8 minutes
• 3G → ~5 minutes
• 4–6G → ~4, 3.2, and 2.7 minutes respectively.

So in practical terms: a modern TL-8 rocket sits right around Traveller 2G in “time to orbit,” even though the crew on a real rocket might feel ~3G during ascent because the engines are also holding them up against gravity. Once you get into 3G and above, Traveller ships are operating in a performance regime no chemical booster can touch.

So a reaction drive at Thrust 1 for an hour costs 2.5% of the ship’s tonnage in propellant. Thrust 2 for an hour is 5%, Thrust 4 is 10%, and so on. A TL-8 booster, by comparison, is basically dumping something on the order of its own mass in propellant over just a few minutes to reach orbit. In Traveller terms, that’s like a grotesquely overpowered reaction drive running at very high “Thrust” and chugging through way more than 10% of the vehicle’s mass in under a tenth of an hour.

 

[phavoc]

A big TL-8 chemical R-Drive —one that chews through ~11,000 lb of propellant per second—effectively behaves like a ~1.8G constant-acceleration vehicle when you look at how fast it actually builds Δv. Modern heavy rockets reach orbit in about 8.5–9 minutes, which works out to roughly that net acceleration once you fold in the full 9.4 km/s LEO budget.

Compare that to Traveller drives:

• 1G → ~16 minutes to reach 9.4 km/s
• 2G → ~8 minutes
• 3G → ~5 minutes
• 4–6G → ~4, 3.2, and 2.7 minutes respectively.

So in practical terms: a modern TL-8 rocket sits right around Traveller 2G in “time to orbit,” even though the crew on a real rocket might feel ~3G during ascent because the engines are also holding them up against gravity. Once you get into 3G and above, Traveller ships are operating in a performance regime no chemical booster can touch.

So a reaction drive at Thrust 1 for an hour costs 2.5% of the ship’s tonnage in propellant. Thrust 2 for an hour is 5%, Thrust 4 is 10%, and so on. A TL-8 booster, by comparison, is basically dumping something on the order of its own mass in propellant over just a few minutes to reach orbit. In Traveller terms, that’s like a grotesquely overpowered reaction drive running at very high “Thrust” and chugging through way more than 10% of the vehicle’s mass in under a tenth of an hour.

Rockets are essentially 3g (or greater) drives. Its not really fair to compare a 1g anti grav drive to a 3g rocket when comparing their time to orbit.

Efficiency wise the Traveller ship takes a little more time but weighs more (its steel). But the energy cost is greatly different. Though a full analysis would require the total number of trips an expendable rocket could make and those costs vs an anti-grav ship total cost and it's cost of operations. If you take amortization and the possible length of time a starship may operate that will skew things towards the starship I expect.

Efficiency would also need to compare how often starship could travel to and from orbit (which is far greater than rocket might manage) to compare the two. If a starship is the turtle and the rocket the hare, if the title can do it 10x in a day and the rocket once, I'd say the starship is more efficient overall.

 

[Condottiere]

Pioneer may present a more realistic mechanic.

But considering that High Guard has reactionary rockets factor/three at technological level seven, that would be a technological fork.

 

[phavoc]

Pioneer may present a more realistic mechanic.

But considering that High Guard has reactionary rockets factor/three at technological level seven, that would be a technological fork.

I wouldn't say so. The Saturn V hit 4.5G before 1st stage cutoff. The Shuttle kept it lower by design. Saturn V didnt have same level of sophistication, and the 1st stage was pretty big, so without the ability to throttle back engines, as the rocket got lighter more force was exerted. Not pleasant for the crew, but they were all in top physical condition, and they volunteered.

 

[MasterGwydion]

I wouldn't say so. The Saturn V hit 4.5G before 1st stage cutoff. The Shuttle kept it lower by design. Saturn V didnt have same level of sophistication, and the 1st stage was pretty big, so without the ability to throttle back engines, as the rocket got lighter more force was exerted. Not pleasant for the crew, but they were all in top physical condition, and they volunteered.

I used the shuttle for my example specifically because it was not as aerodynamic as a missile or rocket. I reasoned that the space shuttle launch would be a closer analog to a Traveller Shuttle lifting off.

 

[phavoc]

I used the shuttle for my example specifically because it was not as aerodynamic as a missile or rocket. I reasoned that the space shuttle launch would be a closer analog to a Traveller Shuttle lifting off.

This comment was meant to reply to the other shuttle comparison comment about effeciency.