The 737 gains it's upward thrust from the shape of it's wings. The engines just provide thrust to get up to speed to provide enough lift. As the air thins the lifting power lessens. It could get by with smaller engines, it would just need a longer runway to get up to the lift speed requried due to it's weight. Although Traveller starships may be streamlined I don't see them as "lifting bodies". The 1G thrust could propel them forward across the surface, but it will not get them off the ground.
Classic Traveller: The Lost Rules
- Thread starter DonM
- Start date
GypsyComet
SOC-14 1K
On topic:
The Type C changed from two pinnaces to two cutters. Not sure if that's what your "Cruiser errata" in the OP meant.
Off (intended) topic:
Striker's rules for starships are approximations, and bad ones at that. Applying the Striker assumptions back to ship design is basically MegaTraveller, and requires some gymnastics to make the standard designs work below TL15.
The whole "1G isn't enough to lift off" argument is founded in taking the simple approach of the rules to silly extremes. Would drives *really* only come in integer increments? Of course not. Is it simpler to limit them that way for the rules? Of course it is. On a 1.00G world, it only takes a drive capable of 1.01G to reach orbit, even if it takes hours or *days*. Are all Size 8 worlds generating exactly 1.00G? Of course not, because they are also not all exactly 8000 miles in diameter, or exactly the same density as "the standard".
The Type C changed from two pinnaces to two cutters. Not sure if that's what your "Cruiser errata" in the OP meant.
Off (intended) topic:
Striker's rules for starships are approximations, and bad ones at that. Applying the Striker assumptions back to ship design is basically MegaTraveller, and requires some gymnastics to make the standard designs work below TL15.
The whole "1G isn't enough to lift off" argument is founded in taking the simple approach of the rules to silly extremes. Would drives *really* only come in integer increments? Of course not. Is it simpler to limit them that way for the rules? Of course it is. On a 1.00G world, it only takes a drive capable of 1.01G to reach orbit, even if it takes hours or *days*. Are all Size 8 worlds generating exactly 1.00G? Of course not, because they are also not all exactly 8000 miles in diameter, or exactly the same density as "the standard".
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Supplement Four
SOC-14 5K
Just to be clear, it's not an argument or an interpretation of the rules. It's how the rules were before the rule was dropped.
Which is on topic.
GypsyComet
SOC-14 1K
It's a bit of "color" I rather like, as it makes the life of the Free Trader slightly more interesting ("can't land there; we'll never leave"), but I also agree with its original removal in CT, since it basically demands more detail than GDW was prepared to offer until Book 6.
Whether you accept the science of the game or not, Traveller has tended to attract those with some scientific knowledge or other rigorous knowledge of an area the game covers (like guns). Keeping that statement in *screams* for more detail and explanation to any gearhead or rockhead who reads it.
Now, however, when the opportunity to present the game as a whole is not only available but already in print, this rule might be usefully brought back as an option, with an explanation as to why it was removed and what its implications are.
In Book 2 ships above 400 tons, the solution is easy: either adopt the MT "overdrive" rule or overbuy your M-Drive by a letter code. In the grand movement rules, you still have 1G, but just enough extra is available to climb out of the wells that would otherwise trap you.
In Book 5 terms, a ship that has non-zero agility has the spare juice to overdrive, but you can also simply install a little extra drive in the first place. Military ships won't have this problem normally since they tend to be fast to begin with (and don't land casually). Of course, I tend not to use Book 5 for RPG ships, since that's not what its for, but many people do.
Whether you accept the science of the game or not, Traveller has tended to attract those with some scientific knowledge or other rigorous knowledge of an area the game covers (like guns). Keeping that statement in *screams* for more detail and explanation to any gearhead or rockhead who reads it.
Now, however, when the opportunity to present the game as a whole is not only available but already in print, this rule might be usefully brought back as an option, with an explanation as to why it was removed and what its implications are.
In Book 2 ships above 400 tons, the solution is easy: either adopt the MT "overdrive" rule or overbuy your M-Drive by a letter code. In the grand movement rules, you still have 1G, but just enough extra is available to climb out of the wells that would otherwise trap you.
In Book 5 terms, a ship that has non-zero agility has the spare juice to overdrive, but you can also simply install a little extra drive in the first place. Military ships won't have this problem normally since they tend to be fast to begin with (and don't land casually). Of course, I tend not to use Book 5 for RPG ships, since that's not what its for, but many people do.
Supplement Four
SOC-14 5K
I like it, too. Since we don't really know how M-Drives really work, you can handwave it to work with real physics so that 1G vessels may leave Size 8+ worlds, and you can handwave it to work with real physics so that 1G vessels cannot leave Size 8+ worlds.
It's not real life physics that's in question here. It's the not-so-real-life M-Drive. I can make up just as many reasons for it not to work as others can make up for it to work.
Bottom line is that it was a real rule (that many people don't know existed), and it was dropped.
Me? I do like it, and I use it in my games.
As you said, it adds some "detail" to the star system, which, for me, makes it a little more "real". Suspension of disbelief and all.
Supplement Four
SOC-14 5K
Don,
What about Jump Masking and Stellar Masking?
Traveller has flirted with it, on and off. Later editions of Traveller make it quasi-canon.
Early Traveller seemed to flirt with it, but then drop it later in the interest of simplicity.
Is that something you want to include?
RE: Simplistic Mask Rule
I've often wanted a simple method for determining whether a planet is masked somehow rather than just GM fiat. Or, go through the process of figuring the main worlds distance from the system star to see if Stellar Masking is in effect.
A nice, simple rule for determining this would be nice. I would welcome it as my first House Rule to CT.
What about Jump Masking and Stellar Masking?
Traveller has flirted with it, on and off. Later editions of Traveller make it quasi-canon.
Early Traveller seemed to flirt with it, but then drop it later in the interest of simplicity.
Is that something you want to include?
RE: Simplistic Mask Rule
I've often wanted a simple method for determining whether a planet is masked somehow rather than just GM fiat. Or, go through the process of figuring the main worlds distance from the system star to see if Stellar Masking is in effect.
A nice, simple rule for determining this would be nice. I would welcome it as my first House Rule to CT.
A Real Rule
Hi, all; my first post here.
Supplement4, I'm curious. You say that this is a real rule, but I'm not seeing it.
Is it just that a 1G M-drive would give a 2" vector up, and a size 8 world would give a 2" vector down (leaving a net 0" vector)?
Because you're stating it like it's a written rule (i.e.; "No ship of 1G acceleration may lift off from a world size 8 or greater."), and I'm not seeing it.
Honestly, I'm not trying to cause trouble; I'm a big fan of a lot of what you've written on this forum. I'm just trying to actually locate the rule you're citing.
Thanks!
Hi, all; my first post here.
Supplement4, I'm curious. You say that this is a real rule, but I'm not seeing it.
Is it just that a 1G M-drive would give a 2" vector up, and a size 8 world would give a 2" vector down (leaving a net 0" vector)?
Because you're stating it like it's a written rule (i.e.; "No ship of 1G acceleration may lift off from a world size 8 or greater."), and I'm not seeing it.
Honestly, I'm not trying to cause trouble; I'm a big fan of a lot of what you've written on this forum. I'm just trying to actually locate the rule you're citing.
Thanks!
mike wightman
SOC-14 10K
You don't apply your vector straight up, you apply it at an angle and then you are into the realms of angular velocity and angular acceleration - ever wonder why rockets and space shuttles aren't fired straight up but follow a curved path into orbit? Or why orbital paths are circular or elipses?
Traveller actually simplifies things a lot by ignoring many frames of reference for ship movement.
Supp 4 is implying a rule that simply doesn't exist. Nowhere in CT does it restrict a 1G ship to any form of movement restriction based on the size of the planetary body.
Back in the early days some people with a very limited understanding of physics interpretted it that way - they were wrong then and they are still wrong.
Traveller actually simplifies things a lot by ignoring many frames of reference for ship movement.
Supp 4 is implying a rule that simply doesn't exist. Nowhere in CT does it restrict a 1G ship to any form of movement restriction based on the size of the planetary body.
Back in the early days some people with a very limited understanding of physics interpretted it that way - they were wrong then and they are still wrong.
mike wightman
SOC-14 10K
Please no jump masking or stellar masking 
In CT an object in jump space is cut off from our universe [full stop] [period] [the end]
Mind you I don't think it flat out states that in the rules anywhere either
In CT an object in jump space is cut off from our universe [full stop] [period] [the end]
Mind you I don't think it flat out states that in the rules anywhere either
Icosahedron
SOC-14 1K
If your thrust exceeds local gravity, you can lift as slowly as you like, straight up. You will still need to expend a fair amount of fuel to reach sufficient speed to achieve a stable orbit, though.
If thrust is less than gravity, your only route to orbit is by building up to orbital velocity within the atmosphere.
This takes considerably more fuel, since the higher atmosphere runs out of 'lift' long before it runs out of 'drag'.
Therefore, although it is possible for low-powered craft to reach orbit eventually, they will need a lot of fuel and will need to withstand a lot of frictional heat. Whether this is feasible IYTU depends on the vehicle construction rules you favour and your own personal bias.
My own personal bias leads me to the opinion that spacecraft have both the fuel reserves and the hull strength to achieve orbit even with low G drives, but forget the 'grav bike and vaccsuit' approach. YMMV
If thrust is less than gravity, your only route to orbit is by building up to orbital velocity within the atmosphere.
This takes considerably more fuel, since the higher atmosphere runs out of 'lift' long before it runs out of 'drag'.
Therefore, although it is possible for low-powered craft to reach orbit eventually, they will need a lot of fuel and will need to withstand a lot of frictional heat. Whether this is feasible IYTU depends on the vehicle construction rules you favour and your own personal bias.
My own personal bias leads me to the opinion that spacecraft have both the fuel reserves and the hull strength to achieve orbit even with low G drives, but forget the 'grav bike and vaccsuit' approach. YMMV
mike wightman
SOC-14 10K
Mine too
In CT ships have enough fuel as standard for 4 weeks continous thrust.
There is a very simple formula, plug 4 weeks and 1g into it and see just how fast a 1g ship is going after this amount of constant acceleration.
(better use it's jump fuel reserves to slow down though ).
Which brings us to relativistic planet-busters lol
In CT ships have enough fuel as standard for 4 weeks continous thrust.
There is a very simple formula, plug 4 weeks and 1g into it and see just how fast a 1g ship is going after this amount of constant acceleration.
(better use it's jump fuel reserves to slow down though
).Which brings us to relativistic planet-busters lol
GypsyComet
SOC-14 1K
Please no jump masking or stellar masking
In CT an object in jump space is cut off from our universe [full stop] [period] [the end]
Mind you I don't think it flat out states that in the rules anywhere either
Stellar masking (ie. the target world is *within* the jump horizon of another body) I have no problem with, as you're trying to *emerge* too close to something, even if it isn't your target. Mid-stream precip is another kettle of fish.
That said, these are NOT a Lost Rule, because they started as JTAS articles, and are thus already in the Reprints.
If thrust is less than gravity, your only route to orbit is by building up to orbital velocity within the atmosphere.
This takes considerably more fuel, since the higher atmosphere runs out of 'lift' long before it runs out of 'drag'.
Therefore, although it is possible for low-powered craft to reach orbit eventually, they will need a lot of fuel and will need to withstand a lot of frictional heat. Whether this is feasible IYTU depends on the vehicle construction rules you favour and your own personal bias.
My own personal bias leads me to the opinion that spacecraft have both the fuel reserves and the hull strength to achieve orbit even with low G drives, but forget the 'grav bike and vaccsuit' approach. YMMV
How would YOU apply this to a typical Free Trader (1G MD taking off from a 1.2G world)?
It would seem to me that even if the shape is a lifting body (a highly suspect assumption) then the ship should reach a maximum speed and altitude in atmosphere where the lift from that shape at that speed and altitude exactly balances the weight of the craft (it cannot climb higher) and the 'thrust' from the MD exactly balances the aerodynamic drag (the craft cannot accelerate to any faster speed). I suspect that this point would be reached long before escaping atmospheric drag and long before reaching orbital velocity.
I was just curious how your thoughts differed (a definitive answer will need to wait for technical details from real reactionless drives, so I'm not holding my breath).
I'd wave my hands furiously, and say the ship has lift modules in the hull.
I would have the starport locals surround the ship laughing til they cry at another big shot "starship pilot" who managed to land and cannot take off again. Then they'd laugh all the way to the bank as a 3G MD heavy transport (non-jump) hauled the starship back to orbit. (But that's just me)
[That is why Traveller has all those costs for shuttling passengers and goods to/from orbit.]
mike wightman
SOC-14 10K
The free trader taxis along the ground and accelerates... at 1g... constantly - by the time it hits 1000mps it is going to lift off.
It then continues accelerating laterally until it has attained 14-18kmps at which point it has escape velocity.
All it takes is time - due to the constant 1g thrust
It then continues accelerating laterally until it has attained 14-18kmps at which point it has escape velocity.
All it takes is time - due to the constant 1g thrust
Very much in the spirit of Classic Traveller.
So IYTU, atmospheric drag also left the universe? (I'm not arguing, just seeking clarification.)
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One thousand meters per second.
What amazing handwavium do you make the tires out of? And have engineers thought of any other uses for it? I know I can...
