CordwainerFish
Emperor Mongoose
Cymbeline is one, if I recall.
Updated Vehicle Handbook in the works
- Thread starter Geir
- Start date
Condottiere
Emperor Mongoose
If I knew that, I'd understand how it operates, more.
Though, now that I think about it, that would make the manoeuvre drive, an ion drive.
Umm, it's literally in the world UPP. It goes from Vacuum to Dense. The Traveller Wiki has the codes if you wanna see for yourself.
Atmosphere - Traveller
Atmospheric pressure is another word for density. A review of the WBH should also explain different world's atmosphere's (though it may not specifically call out what that means for flying objects vs personnel on the surface).
Pressure is mentioned elsewhere, such as pressure from water depth, or pressure in a gas giant. There's LOTS of things the rules don't specifically address, doesn't mean they aren't there though.
Arkathan
Emperor Mongoose
No one worries about the effects of water pressure increasing with depth until they try to visit a deep sea trench in a tin can.
THEN it becomes a relevant topic that's resolved itself before you know it.
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Terry Mixon
Emperor Mongoose
The Titanic sub. Too soon?
Geir
Emperor Mongoose
Blue light drives... mumble... mumble.. Cherenkov... mumble.
I think I mentioned earlier that in a homebrew attempt to make an 'antigravity drive' using actual energy numbers for power input, there was almost no way to make something practical that couldn't be manipulated into a perpetual motion machine.
But I think I was looking at it to narrowly. A hydroelectric powerplant is essentially a gravity-driven perpetual energy machine driven by a perpetual falling of water, in a narrow sense.
But in the broader sense, it's not, because weather is the power source (okay, more like solar evaporation, wind, condensation, rain, and then gravity). So... this is why I like the 1000D limit*: and how I can 'explain' (yes, handwave) away not only m/g/lifter drives and the lack of giant thermal radiators on every single spaceship with a thrust greater than 0:
Look at the bigger energy picture: like the turbine in the dam, the m-drive is actually stealing power from a giant system, in the case of the 'anti-gravity' drive, it's the planet or star's entire space-time-warpy thing (not a a Real Physics Thing™ so don't quibble) - so you're 'borrowing' energy from the well and dumping energy (heat) into the well (yes, the heat is from the power plant and not so much the m-drive but it's running down azucchini zuchai crystal conduit into the thing that makes the blue light glow (yes, I know I mixed in a j-drive part, but it's the make-believe/suspend belief idea, not the make-believe physics that matters (and I wanted to make a zucchini joke).
Point is gravity gradient makes it 'go' gravity gradient 'eats' the heat - net result - the planet gets ever so slightly warmer. Which also happens when you run that turbine in the damn.
*So why no m-drive past 1000D? Well, too little gradient from the nearby object and too shallow gradient from the galactic bulge to eke out more than 1%.
But it's all just a thing to allow enough suspended belief to play a TTRPG.
(Yeah, the conversation wander off this a bit, off of vehicles entirely, but I was typing erratically over time between meetings and you guys keep posting, which is not a bad thing).
I think I mentioned earlier that in a homebrew attempt to make an 'antigravity drive' using actual energy numbers for power input, there was almost no way to make something practical that couldn't be manipulated into a perpetual motion machine.
But I think I was looking at it to narrowly. A hydroelectric powerplant is essentially a gravity-driven perpetual energy machine driven by a perpetual falling of water, in a narrow sense.
But in the broader sense, it's not, because weather is the power source (okay, more like solar evaporation, wind, condensation, rain, and then gravity). So... this is why I like the 1000D limit*: and how I can 'explain' (yes, handwave) away not only m/g/lifter drives and the lack of giant thermal radiators on every single spaceship with a thrust greater than 0:
Look at the bigger energy picture: like the turbine in the dam, the m-drive is actually stealing power from a giant system, in the case of the 'anti-gravity' drive, it's the planet or star's entire space-time-warpy thing (not a a Real Physics Thing™ so don't quibble) - so you're 'borrowing' energy from the well and dumping energy (heat) into the well (yes, the heat is from the power plant and not so much the m-drive but it's running down a
Point is gravity gradient makes it 'go' gravity gradient 'eats' the heat - net result - the planet gets ever so slightly warmer. Which also happens when you run that turbine in the dam
*So why no m-drive past 1000D? Well, too little gradient from the nearby object and too shallow gradient from the galactic bulge to eke out more than 1%.
But it's all just a thing to allow enough suspended belief to play a TTRPG.
(Yeah, the conversation wander off this a bit, off of vehicles entirely, but I was typing erratically over time between meetings and you guys keep posting, which is not a bad thing).
IanBruntlett
Emperor Mongoose
"Concealed Manouevre Drive" is on page 45 of High Guard Update 2022.
Manoeuvre drives, whose function is described in
Ship Design on page 15, use thruster plates to move
a ship without the need for propellant. Manoeuvre
drive thruster plates are typically located on the outer
surface of a ship (facing aft is standard) where they
can perform best. While acceleration to their facing is
optimised, a ship may accelerate in other directions at
reduced thrust without turning the ship to a new facing.
For example, thruster plates can accelerate a ship at
up to 25% of their maximum thrust to port or starboard
and 10% to fore. Therefore, a ship with Thrust 4 could
exert one G of thrust to left or right and 0.4G to fore
without the need to turn the ship on its axis.
As such, thruster plates need not be exposed at all
and can optionally be concealed behind bulkheads.
This rather severely degrades performance but there
are some ship designs that are willing to accept the
trade-offs for added stealth. See the Sensors chapter
on page 55 for more information about features that
make a ship easier to detect, including the use of their
manoeuvre drives.
Concealed manoeuvre drives are contained within
ship bulkheads but must be within three metres of the
accelerating surface of the ship. Concealed manoeuvre
drives add 25% to the tonnage and cost of the drive.
The additional tonnage comprises a system that
contains and exhausts thruster plate ionisation out of
specially designed ports, reducing their detectability
to almost nil. Concealed manoeuvre drives cut
performance in half (round down), so a ship with Thrust
2 is reduced to 1 and so on. These drives are designed
to operate within confinement, so simply removing the
outer bulkhead does not add to their performance.
Condottiere
Emperor Mongoose
It's the three metres that's interesting.
The length of a spacecraft tends to exceed that.
The length of a spacecraft tends to exceed that.
MasterGwydion
Emperor Mongoose
My point is that nowhere in the rules does it tell you what changes if you gain 30,000 feet of altitude, so therefore, nothing happens. Same rules apply at 30,000 feet as at sealevel. Therefore, pressure is a constant.Umm, it's literally in the world UPP. It goes from Vacuum to Dense. The Traveller Wiki has the codes if you wanna see for yourself.
Atmosphere - Traveller
wiki.travellerrpg.com
Atmospheric pressure is another word for density. A review of the WBH should also explain different world's atmosphere's (though it may not specifically call out what that means for flying objects vs personnel on the surface).
Pressure is mentioned elsewhere, such as pressure from water depth, or pressure in a gas giant. There's LOTS of things the rules don't specifically address, doesn't mean they aren't there though.
Terry Mixon
Emperor Mongoose
Maths clouding brain... Consciousness fading...
Geir
Emperor Mongoose
I was just responding to the 'nowhere in the rules' part, not on whether or not you needed a calculator... and a reason.
Most of the WBH is a big long FYI, use it if you want to, sort of thing... it even says so in the intro.
MasterGwydion
Emperor Mongoose
So how does a "thruster plate" provide reverse thrust when it is not facing that direction? All of this goes away and becomes way simpler if the M-Drive is omni-directional. No need for lifters on spaceships either. No need to come up with reasons to have the Sci-fi staple blue light engines on the back of the ship. It just works better.
What you guys and Mongoose seem to be describing is more of an outboard motor, but for space. I use an M-Drive as a "falling engine" instead of a "thrusting engine". What does an M-Drive do? It creates an intense but extremely localizaed gravity field that makes you "fall" in the direction of travel at a rate of 1G or 2G etc. They do not provide "thrust" as other engines do.
Treating it like this fixes every single issue with M-Drives. It also explains why facing isn't an issue in spaceship combat, since the drive is omni-directional, you can travel facing any direction you like.
Look at how much text was used above to explain something that never needed to be that complicated to begin with. All that is required is to let go of the idea that M-Drives provide thrust through "thruster plates" and that ships must have big, glowy engines sticking out of the back. Heck even the rules don't support the who big engines out the back of the ship-style of play. An M/1 drive only takes up 1% of a ship. So, no big engines on that one, just tiny ones.
Also, HG pg.15 thruster plates are described as, "Thruster plates use gravitic technology to move a ship without the need for exhaust propellant. When in operation, thruster plates build up an ionisation field that glows blue. The higher the thrust employed, the brighter and more vibrant the blue colour appears."
This tells us that somehow using gravitic technology causes ionization. Doesn't this also mean that you can take radiation damage from standing too close to an M-Drive?
The more complicated the explanations get the less useful it is in play. Watch...
"The M-Drive creates a momentary depression in spacetime within millimeters of the hull in the direction of travel and the ship "falls" along that line and is described by how many Gs (acceleration of due gravity on Earth, at sea-level) of acceleration the field can generate."
There. Easy. No need for huge write ups on something that should be kept simple. A blurb could be added as well in regard to inertial compensators as well. Either that, or Mongoose needs to decide on an overarching theory for how gravitic technology works in Charted Space and make sure the writers stick to it.
Also, what atoms are being ionized by the thruster plates to glow blue. There is an average of 40 atoms per cubic meter in space. So what is glowing blue?
Sigtrygg
Emperor Mongoose
It is pure handwavium though.
""The M-Drive creates a momentary depression in spacetime within millimeters of the hull in the direction of travel and the ship "falls" along that line and is described by how many Gs (acceleration of due gravity on Earth, at sea-level) of acceleration the field can generate."
That would require a huge amount of energy, putting depressions into spacetieme has an equation that describes it already...
R_{μν} - (1/2) R g_{μν} + Λ g_{μν} = (8 π G / c^4) T_{μν}
R_{μν} : Ricci curvature tensor
R : Scalar curvature
g_{μν} : Metric tensor
Λ : Cosmological constant
G : Gravitational constant
c : Speed of light in a vacuum
T_{μν} : Stress-energy tensor
""The M-Drive creates a momentary depression in spacetime within millimeters of the hull in the direction of travel and the ship "falls" along that line and is described by how many Gs (acceleration of due gravity on Earth, at sea-level) of acceleration the field can generate."
That would require a huge amount of energy, putting depressions into spacetieme has an equation that describes it already...
R_{μν} - (1/2) R g_{μν} + Λ g_{μν} = (8 π G / c^4) T_{μν}
R_{μν} : Ricci curvature tensor
R : Scalar curvature
g_{μν} : Metric tensor
Λ : Cosmological constant
G : Gravitational constant
c : Speed of light in a vacuum
T_{μν} : Stress-energy tensor
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MasterGwydion
Emperor Mongoose
Great for worldbuilding, not so much for trying to run an RPG at the table.
MasterGwydion
Emperor Mongoose
I am not saying that it doesn't require a ton of energy, but then again actual energy costs in real life are not considered in Traveller.
Condottiere
Emperor Mongoose
Wireless energy transmission.
Arkathan
Emperor Mongoose
Rule Zero. Go with what you know. It's not Warhammer. GW won't be stalking your table, enforcing compliance and examining mini's for included equipment.
Think of it like the inclusion of lifters lets you take off from worlds up to two G. But lifters don't add to velocity (on the scale of an M-Drive) and aren't any good at all once you are orbital. In atmosphere, require aerodynamics for extra lift.
It doesn't break the game and there really aren't a lot of worlds being inhabited by humans where they are under 2G conditions.
When dipping into a gas giant, rely on velocity to get back out again. Ride that roller coaster.
OR look at lifters as a remnant of that omni-directional capability you remember, just nerfed in space.
Think of it like the inclusion of lifters lets you take off from worlds up to two G. But lifters don't add to velocity (on the scale of an M-Drive) and aren't any good at all once you are orbital. In atmosphere, require aerodynamics for extra lift.
It doesn't break the game and there really aren't a lot of worlds being inhabited by humans where they are under 2G conditions.
When dipping into a gas giant, rely on velocity to get back out again. Ride that roller coaster.
OR look at lifters as a remnant of that omni-directional capability you remember, just nerfed in space.
CordwainerFish
Emperor Mongoose
Pressure is related to density - pV = nRT and all that.
J. L. Brown
Emperor Mongoose
This is why real-world units and thorough sanity checks throughout the rules are important; because the game benefits from being a universe simulator. The Rules-writers go with the assumption 'everything in the game works exactly like reality does -- except this particular specific hand-wave which we spell out to describe FTL travel'. That means that rules for air pressure at altitude, or solubility of stuff in water, or velocity to maintain a particular orbit, or etc DO NOT need to be written; the GM just uses (as much or as little of) the real world as needed.