CT Only: GRAVITY! ...And the M-Drive...and Man...and Worlds.

[AnotherDilbert]

I was looking through my CT stuff, trying to find what has been written about M-Drives, and I'm a little shocked that, really, there is precious little.

Book 5, pg. 17 answers the question about where to draw the line with streamlining and world types. All ships can land on worlds with Atmo 0 or 1. Any other world requires streamlining.

I see that as a necessary, but not sufficient, condition.

The starship movement rules in LBB2 describes what happens when you try to land on a world with higher gravity than the rating of your M-drive: You will impact with high speed.

 

[Jame]

I see that as a necessary, but not sufficient, condition.

The starship movement rules in LBB2 describes what happens when you try to land on a world with higher gravity than the rating of your M-drive: You will impact with high speed.

I read in a GURPS Trav book, I dont remember which, that a number of standard designs are rated to something like 1.2 g so they can land and take off if normal worlds without trouble.

I just handwave it by saying that most ships, including the Type M, have a gravitic unit like an air raft's. This allows them to land on most worlds, eg non gas giants, with some care - eg nit under fire.

 

[mike wightman]

The 77 CT m-drive was a fusion rocket, this is explicit in 79 HG. In LBB2 a ship has enough fuel for 48 hours of continuous burn [top of page 6]. Also the rules for smallcraft require them to 'burn' fuel to maneuver.

When GDW decided to take Traveller back in house and revise it Frank Chadwick wanted to go back to reaction drives as per the original CT intent.

 

[Supplement Four]

LBB2, p6: (TTB, p51)
Military ships are assumed to have purifiers, just as they are assumed to have better sensors, but the design system in LBB2 is not that detailed.

There are military ships in Supp 7 that don't have fuel purifiers. The Destroyer Escort, the Merc Cruiser, the Troop Carrier, the SDB...etc.

 

[mike wightman]

But they are military and thus have the rugged military drives needed to avoid unrefined fuel penalties...

 

[Supplement Four]

But they are military and thus have the rugged military drives needed to avoif unrefined fuel penalties...

Not according to Supp 7. It's a contradiction in the CT rules. The Fuel Treatment line in the stat blocks in that book speaks to it.

 

[creativehum]

Streamlining comes in two forms: With or without wings.

Regular streamlining implies no wings or aerodynamic lift, it simply means that the ship will not disintegrate or burn up if it is moved through an atmosphere. Example: Type S Scout.

If it has wings it can fly or glide like an aircraft (or the space shuttle). Example: Serpent-class Scout.

Most streamlined ships have no wings, and must rely on their M-drives for lifting force.


The SSOM explicitly describes how streamlined ships descend on their tails like rockets, and turn 90° at the last moment to land with the decks level with the ground. No anti-grav or runways required.

Good point.
I was explicitly talking about those with wings. But yes, others will land and take off as described in the quote from the SSOM.

 

[AnotherDilbert]

But they are military and thus have the rugged military drives needed to avoif unrefined fuel penalties...

Not according to Supp 7. It's a contradiction in the CT rules. The Fuel Treatment line in the stat blocks in that book speaks to it.

Not necessarily a contradiction, the rules do not require all military ships to have purifiers or ruggedised drives.

According to S7 the Far Trader and the Subbie have purifiers, but the Scouts, Patrol Cs, and SDBs doesn't? It might be canon, but that won't happen IMTU.

 

[mike wightman]

Not according to Supp 7. It's a contradiction in the CT rules. The Fuel Treatment line in the stat blocks in that book speaks to it.

There is no contradiction if you stick with LBB2 and ignore HG.

HG contradicts so much of LBB2...

All military ships in a LBB2 universe have rugged drives and do not suffer the unrefined fuel penalty.

Military ships under HG rules require a fuel purification plant to avoid the unrefined fuel penalty.

Don't you just love how well the two similar but very different ship paradigms don't support each other on many key points

[drive sizes, pp fuel, drive TL progression to name just three pretty important ones]

 

[kilemall]

Not necessarily a contradiction, the rules do not require all military ships to have purifiers or ruggedised drives.

According to S7 the Far Trader and the Subbie have purifiers, but the Scouts, Patrol Cs, and SDBs doesn't? It might be canon, but that won't happen IMTU.

I could see things like the Cs being civilianized versions.

Probably incurs an additional cost to have the unrefined feature, but the military/scouts buy in bulk and standardize.

Buying surplus military ships or drives that have not been demilitarized could be a desirable miniquest.

 

[kilemall]

There is no contradiction if you stick with LBB2 and ignore HG.

HG contradicts so much of LBB2...

All military ships in a LBB2 universe have rugged drives and do not suffer the unrefined fuel penalty.

Military ships under HG rules require a fuel purification plant to avoid the unrefined fuel penalty.

Don't you just love how well the two similar but very different ship paradigms don't support each other on many key points

[drive sizes, pp fuel, drive TL progression to name just three pretty important ones]

Eh, I'll post the ref argument I use, again, just for others that have not seen it.

LBB2 ships are built off letter drive standardized components, like say standard diesel engines in RL that can be used in ships tanks or locomotives. They are more TL-independent and more an engineering standard, which makes it easier to build the parts and support commercial/patrol activities out on the frontier past TL13+ clusters.

HG are all custom builds, so unusual builds can happen for ACS but also the big warships and megacorps trade lane ships are covered beyond the pale of the average Traveller to own or operate (post-career). They are very TL-dependent as per TCS. The sort of thing that won't be built in runs of 1000s or require frontier maintenance.

 

[AnotherDilbert]

There is no contradiction if you stick with LBB2 and ignore HG.

HG contradicts so much of LBB2...

I agree that LBB2 and HG disagree on a lot of things, but this is more a question of level of detail. LBB2 states military ships often can use unrefined fuel, HG describes how you make that happen.

All military ships in a LBB2 universe have rugged drives and do not suffer the unrefined fuel penalty.

We are reading a lot into a dependent clause here:

Military and quasi-military starships often use unrefined fuel because it is more available, and because their drives are specially built to use it.

I have always interpreted that to mean that military (and scout) ship often (not always) have drives built to use unrefined fuel.

 

[mike wightman]

If only they had included a one off cost in LBB2 - a surcharge for rugged drives if you like. It could be similar to the way streamlining is handled in LBB2 - a one off cost built in at the design stage.

 

[creativehum]

We are reading a lot into a dependent clause here.

Military and quasi-military starships often use unrefined fuel because it is more available, and because their drives are specially built to use it.

The weird thing is (and I only just noticed this) the "often" refers to use of unrefined fuel, while it states the drives of such ship are built to use it.

So, it seems as if the ships are built ruggedly enough to handle unrefined fuel (according to Book 2) and that they "often" use unrefined fuel -- even though they apparently could use unrefined fuel whenever they want.

By the way, I'm not stating anything about the way people should set up the technology for their settings. I'm the guy always running around making it clear every table of Traveller play will be, by definition, it's own thing. Only pointing out that the "often" is in reference to the fuel, not the ability of military and quasi-military starships to handle unrefined fuel.

As for me, I think purifiers are more trouble than they are worth, military and quasi-military starships are ruggedly built to handle unrefined fuel for a longer period of time than civilian craft, but after enough jumps using unrefined fuel the drives of even these rugged ships will fail if they do not go into port for a solid cleaning.

 

[AnotherDilbert]

If only they had included a one off cost in LBB2 - a surcharge for rugged drives if you like.

The LBBs are very compact. They had to leave a lot of things out. Even-so they are surprisingly complete as a game.

 

[creativehum]

If only they had included a one off cost in LBB2 - a surcharge for rugged drives if you like. It could be similar to the way streamlining is handled in LBB2 - a one off cost built in at the design stage.

The LBBs are very compact. They had to leave a lot of things out. Even-so they are surprisingly complete as a game.

The thing is, per Marc Miller's comments that there was no plan for additional Traveller material after the game's publication, I don't think the game assumed there would be much need or focus on military craft. Looking at Books 1-3 there is a focus on adventure at the civilian and para-military level. Military vessels might be encountered by the PCs in their Type A merchant. But it would be an encounter for the Players/PCs to deal with, resolve, and deal with from the point-of-view of the PCs. (In other words, the PCs encounter a huge, dominating vessel that wants something from them, or wants to block them from getting to what they want. Now what? Adventure ensues..)

The Referee wouldn't be focused on how that military vessel managed to get around three months from now. It wasn't expected the PCs would be in charge of a naval vessel and be concerned about such thing. (They had left the service to go adventure.) Simply knowing enough to get a sense of how it worked -- rugged engined, greater range, could pop up more quickly and easily than other ships the PCs had encountered -- would be enough to go on.

The Referee could add more detail about the ship and military vessels if he wanted. But at the time, and with the expectations of RPGs at the time (both Gygax and Miller thought "You make the game, they buy, they go off and make worlds and adventures, you're done") I believe any focus on military vessels beyond what is already there would pull focus from the core conceit of the game.

 

[aramis]

Thanks for the back-handed compliment, but what, from what I've said, is non-OTU from a CT-only perspective? Just the White Dwarf rocket stuff?

Nothing backhanded about it. Your assumptions simply do not match some of the assumptions baked into the later editions, and thus the OTU.

That streamlined 1G ships cannot take off from a Size A+ world moves you out of the OTU; MT, TNE, T4, and T5 all presume you can, and MT, TNE, and T4 all drop even the streamlined requirement (MT by overthrust, TNE/T4 by contragrav). T5 imposes a friction limit and requires wings if local G ≥ thrust. It's worth noting as well: the Air/raft's time to orbit in CT (hours=world size) is the same as the default time in T5 for ships. Bk2 and TTB are curiously silent on the matter.

Artificial Gravity is a staple element of the OTU as well. The OTU really begins in Bk 4, but takes its shape in Bk 5 and Advs 5+...

And, if one has Bk 5, another solution presents itself for TL 10+ size 8+ worlds with at least a D-port... Repulsor bays! (Not my idea - Jeff Swycaffer's, in Dragon 59.)

The WD stuff is also non-OTU and non-canon, and hard to find legally. Tho' Andy Slack used to have his WD articles on his website.

There's nothing wrong with playing traveller outside the OTU. Just note that the OTU has a different set of answers to a number of issues.

Oh, and the airframe type in t20? Specifically included to allow 1G ships on a 1.2G world...

Also note: The thrust to weight of a 747 is about 0.27... https://www.grc.nasa.gov/www/k-12/BGP/Donna/t_w_ratio_answers.htm

With unlimited fuel and 4x the thrust, and that thrust not being atmosphere dependent? No reason such an airframe cannot get to orbit. CT doesn't differentiate airframes from non-airframe streamlined.

 

[AnotherDilbert]

The weird thing is (and I only just noticed this) the "often" refers to use of unrefined fuel, while it states the drives of such ship are built to use it.

Unfortunately that is true. It was probably 35 years since I read that last time.

I interpret all such statements as generally, but not always, true.
All military ships have ... = Most military ships have ...
All G/Carriers ... = Most G/Carriers ...

 

[ffilz]

The weird thing is (and I only just noticed this) the "often" refers to use of unrefined fuel, while it states the drives of such ship are built to use it.

So, it seems as if the ships are built ruggedly enough to handle unrefined fuel (according to Book 2) and that they "often" use unrefined fuel -- even though they apparently could use unrefined fuel whenever they want.

Note the 1977 text:

For all jumps (in any situations) throw 12+ for a misjump to occur. DM: +5 if within 100 planetary diameters of a world or star; +3 if using unrefined fuel (except military and scout ships); –1 if using refined fuel; +2 if operating beyond the required date for annual maintenance.

Military ships have a 12+ misjump with unrefined fuel and a 13+ with refined.

Non-military ships have a 9+ with unrefined and a 13+ with refined.

Military ships will still use refined fuel when available.

In 1981 this text is changed:

Misjump: Each time the ship engages in a jump, throw 13+ for a misjump: Apply the following DMs: +1 if using unrefined fuel (and not equipped to do so), +5 if within 100 planetary diameters of a world, +15 if within 10 planetary diameters of a world. If the result is 16+, then the ship is destroyed.

Now military ships are 13+ to misjump with unrefined or refined fuel while non-military ships are 12+ with unrefined and 13+ with refined.

A significant difference, called out in my section by section comparison:

https://docs.google.com/document/d/1jsH-EgKvaR0mdbtJMj_Xj7X3TcYyZTqQGf-Gwu58PX0/edit?usp=sharing

 

[creativehum]

Thanks for that, Frank!