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

[Supplement Four]

<Shrug> I don't think there is a canon answer to the question of fuel use during takeoff- more a matter of what effect you want.

I don't know if this helps you...but, the Speeder, page 111 TTB, has unlimited range, can make orbit in one hour, and must re-charge the batteries once every 10 weeks from a ship's powerplant.

Though not a startship, it is a second canon example that leads one to believe that fuel used to get to orbit is inconsequential with Traveller tech.

 

[creativehum]

For what it's worth, the deck plans for the March Harrier do not show f pier landing structures, but the description from The Traveller Adventure says:

"The ship itsalf rests on large landing gear pylons which
hold the ship at a standard height above the ground. These
pylons are capable of "kneeling" to change height and place
the cargo deck and bow doors at a better level for cargo
loading and unloading."
-- p. 130

 

[kilemall]

There might be in other editions of Traveller. Did you check the SOM?

Don't have it. Not terribly important to me, I work in fuel-days,n ormal takeoff is the same as normal ops, and burning double G goes heavy reaction mass and one days' worth of fuel every 100 seconds. Gives me fuel drama with a minimum of bookkeeping.

 

[Supplement Four]

Don't have it. Not terribly important to me, I work in fuel-days,n ormal takeoff is the same as normal ops, and burning double G goes heavy reaction mass and one days' worth of fuel every 100 seconds. Gives me fuel drama with a minimum of bookkeeping.

I do understand that.

Do you have any TNE? I remember G-Burns from the space combat game, Brilliant Lances. That may or may not help. I think G-Burns were also addressed in the core book space combat rules.

As for CT, I did find a clear statement: Page 17, Book 5. "Fuel consumption for maneuver drives is inconsequential, and it is assumed to be part of the power planet consumption, regardless of the degree of maneuver undertaken."

 

[kilemall]

I don't know if this helps you...but, the Speeder, page 111 TTB, has unlimited range, can make orbit in one hour, and must re-charge the batteries once every 10 weeks from a ship's powerplant.

Though not a startship, it is a second canon example that leads one to believe that fuel used to get to orbit is inconsequential with Traveller tech.

That's grav with a lot more grav module to weight ratio.

A TL15 speeder is likely to have that sort of battery power, but batteries drop off pretty quickly in capacity at lower TL according to Striker, so I would expect something slower and less juice at TL10, MTU TL.

As i posted here and elsewhere, my ships can have combinations of grav and reaction for differently purposed ships, and I don't bother with fuel calculations for most of it.

 

[kilemall]

I do understand that.

Do you have any TNE? I remember G-Burns from the space combat game, Brilliant Lances. That may or may not help. I think G-Burns were also addressed in the core book space combat rules.

As for CT, I did find a clear statement: Page 17, Book 5. "Fuel consumption for maneuver drives is inconsequential, and it is assumed to be part of the power planet consumption, regardless of the degree of maneuver undertaken."

I got Brilliant Lances and am going over that as many have said they consider it the height of Traveller ship combat for the battle/engineering/maneuver drama i am looking for. I am looking ultimately to get a maneuver version of HG done.

The reaction drives of that version are nice, but I am looking for a lot of action in the Oort Cloud plus frac-C scout cruisers, so the fuel limits are too extreme. At the same time grav drives won't do Out There.

Gameplay effect and feel first, retain as much of the rules to service that second.

 

[Supplement Four]

M-Drives

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.



Book 5, pg. 22 describes the M-Drive as one amazing piece of machinery. The drive is used for planetary, atmospheric operations (we know, because there is no other drive besides the Jump Drive), inter-system operations, and it is responsible for what some call the "inertial dampener".

Not only does the M-Drive move the vessel in N-Space and in world atmospheres (if streamlined), but it also keeps the crew protected from high-G maneuvers, comfortable in a 1G field (this is on page 17).

There's some contradiction (or maybe not...maybe Traveller ships use both systems in tangent) in Sup 7, page 7, where gravity is discussed. There, it says that ships use a piece of equipment called an Acceleration Compensator. Evidently, not all ships have these installed. I guess that a ship with a 1G M-Drive wouldn't need them. But they work in tangent with the deck plates (that have grav units integral to them).






FUEL PURIFICATION.

What's up with Fuel Purifiers? I've seen plenty on deck plans. But, there's no such animal noted in TTB that I can see.

I have heard that the '77 rules had a purifier. Is that true?

I'm guessing it was taken out so that PC ships would have to risk misjumps if they used unrefined fuel. If fuel purifiers are available, then every ship is most likely going to have them--paid for as part of the total ship cost in the monthly payment.

If fuel purifiers are abundant, then there's no real risk in using unrefined fuel. A captain can buy it cheap at the starport or skim it in an ocean or at a gas giant.

I could see the fuel purifiers being taken out (if they were even in the Book 2 rules) in order for there to be a risk for the players, giving them a decision: Buy or skim unrefined fuel, save the money, and risk misjump, or buy refined fuel at five times the cost.



But, when you get to Book 5 and Adventure 5, the Fuel Purifiers pop back up. Maybe they're only used in very large vessels? The ones in Book 5 are based on 1,000 tons fuel capacity.

Book 5. pg. 27 states that smaller fuel purifiers exist, to a minimum of a 1/5th the tonnage and price shown.

So...is that the reason Adventure Class ships don't have fuel processors? They take up too much space?

We don't really know what TL craft is the March Harrier from TTA. If the vessel was constructed at the Aramis port, then it's a TL B starship. According to Supp 7, the Type R is a TL 9 design.

If the Harrier is a TL B design, then 7 tons of the ship must be re-allocated to the fuel purification machinery (with an added cost of Cr 34,000. I think it's the lost tonnage that is most important.

IF the Harrier is a TL 9 design, then 9 tons must be re-allocated to this machinery (at a cost of Cr 38,000).

That's a loss of almost 5% of its 200 ton cargo space. Or, I guess you could tear out 2-3 staterooms, carrying less passengers.

Is that worth it? Getting by on unrefined fuel--which is a hell of a bonus, evaporating a lot of operating expense. But, a 5% reduction in cargo capacity, or the loss of 2-3 passenger staterooms, does eat into a ship's profitability, trip after trip, jump after jump.

 

[Supplement Four]

That's grav with a lot more grav module to weight ratio.

A TL15 speeder is likely to have that sort of battery power, but batteries drop off pretty quickly in capacity at lower TL according to Striker, so I would expect something slower and less juice at TL10, MTU TL.

In TTB, it's a TL 8 vehicle.

 

[Supplement Four]

I am looking ultimately to get a maneuver version of HG done.

I'm sure you've looked at Mayday. Again, I'm not sure if it will help, but there's a HG to Mayday conversion in JTAS. That work may be done for you. HG combat and design with Mayday vector movement (movement on a bigger scale than Book 2).

 

[creativehum]

FUEL PURIFICATION.

What's up with Fuel Purifiers? I've seen plenty on deck plans. But, there's no such animal noted in TTB that I can see.

I have heard that the '77 rules had a purifier. Is that true?

I'm guessing it was taken out so that PC ships would have to risk misjumps if they used unrefined fuel. If fuel purifiers are available, then every ship is most likely going to have them--paid for as part of the total ship cost in the monthly payment.

If fuel purifiers are abundant, then there's no real risk in using unrefined fuel. A captain can buy it cheap at the starport or skim it in an ocean or at a gas giant.

I could see the fuel purifiers being taken out (if they were even in the Book 2 rules) in order for there to be a risk for the players, giving them a decision: Buy or skim unrefined fuel, save the money, and risk misjump, or buy refined fuel at five times the cost.

There are no Fuel Purifiers in 1977 edition.

Fuel Purifiers are introduced in Book 5.

You point out all the ramifications of their introduction. This is one of the reasons I state that Book 5 changed everything for Classic Traveller.

As for the March Harrier, I believe all the ships in The Traveller Book are built with the Basic Traveller rules (that is: Books 1-3, or The Traveller Book, or Starter Traveller). Thus... no purifier. The logic at the time seems to be that as long as you had a version of Basic Traveller you could play most of the adventures. But this got squishy over time -- in part because the Third Imperium was built on ships that required Book 5.

 

[kilemall]

I'm sure you've looked at Mayday. Again, I'm not sure if it will help, but there's a HG to Mayday conversion in JTAS. That work may be done for you. HG combat and design with Mayday vector movement (movement on a bigger scale than Book 2).

Bleh. Not the effect I want.

 

[Supplement Four]

There are no Fuel Purifiers in 1977 edition.

I thought someone had given me a formula at one time for Fuel Purifiers. Maybe it was from the first edition of Book 5--were they slightly different between HG editions?

You point out all the ramifications of their introduction. This is one of the reasons I state that Book 5 changed everything for Classic Traveller.

Yes, I think I would House Rule this so that purifiers required more space so that small ships would give up too much money-earning space to have them, yet they'd still be available for special designs of ships built not to earn a living through cargo and passengers.

The handwave would be easy, saying that unrefined fuel in small quantities only had the misjump issue (which only gives the ship a 3% chance of mis-jump)--so they are used on Adventure class vessels often.

But, when you're talking about large amounts of unrefined fuel, the problem compounds. It's an issue for larger starships and capital class ships.





EDIT: It is interesting that Book 5 includes (introduces, as you say) the Fuel Purifier, but HG stats do not reference it. If you need to know if a ship has them, then you either assume that all large ships do use them. Or, you have to see some notation in the ship's notes. For example, the Kinunir, at the back of Book 5, states fuel scoops and purifier in the notes, but nothing i s listed about the Unicorn.

I would think that there should be a place for it in the Book 5 USP, but there isn't.

The Unicorn is a 300 ton vessel with drop tanks. Again, see a small ship with no fuel purifier. I wonder why.





Supp 9 has a line for Fuel Treatment in its stat block where notes are made about purification plants, scoops and such.

 

[kilemall]

Fix for purifiers is space and money.

10x tonnage for normal price and performance.

Divide that tonnage and process capacity by 2-5, and multiply 2-5 cost.

So most purifiers are 400+ tonnage, suitable only for fleet tankers capital ships and stations/bases, but you can still get an 80 ton unit for a phenomenal price for highly specialized spec ops/exploration craft.

 

[Supplement Four]

Fix for purifiers is space and money.

10x tonnage for normal price and performance.

Divide that tonnage and process capacity by 2-5, and multiply 2-5 cost.

So most purifiers are 400+ tonnage, suitable only for fleet tankers capital ships and stations/bases, but you can still get an 80 ton unit for a phenomenal price for highly specialized spec ops/exploration craft.

Or...just don't allow, or change, the 1/5th rule. You can't make 'em smaller, but you can still use them in HG capital ship designs.

 

[creativehum]

EDIT: It is interesting that Book 5 includes (introduces, as you say) the Fuel Purifier, but HG stats do not reference it. If you need to know if a ship has them, then you either assume that all large ships do use them. Or, you have to see some notation in the ship's notes. For example, the Kinunir, at the back of Book 5, states fuel scoops and purifier in the notes, but nothing i s listed about the Unicorn.

I would think that there should be a place for it in the Book 5 USP, but there isn't.

The Unicorn is a 300 ton vessel with drop tanks. Again, see a small ship with no fuel purifier. I wonder why.

Supp 9 has a line for Fuel Treatment in its stat block where notes are made about purification plants, scoops and such.

I'm going to go out on a limb here and say a lot of this was done haphazardly during the life of the Classic Traveller line. This is how we get the Kinunir class Battle Cruiser, a 1200 ton displacement ship that later has to be retconned into not really being a Battle Cruiser because while it was a perfectly fine size by Book 2 rules, it becomes ridiculous once Book 5 comes out and the ships of the Third Imperium fleet become ginormous against the scale established in Book 2.

Another point: Each edition of Basic Traveller notes that military vessels and scout vessels do not suffer ill-effects for using unrefined fuel. So maybe the ship descriptions of military vessels do not mention Fuel Purifiers because it is assumed they will have them.

 

[Whipsnade]

ISTR that Annic Nova lists a fuel use per hour stat for the pinnaces.

Of course, Annic Nova is so wacky and ur-Traveller that stat may be of no help at all!

 

[AnotherDilbert]

FUEL PURIFICATION.

What's up with Fuel Purifiers? I've seen plenty on deck plans. But, there's no such animal noted in TTB that I can see.

LBB2, p6: (TTB, p51)

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

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.

 

[mike wightman]

A better option for HG, with hindsight, would have been the introduction of rules for rugged military drives rather than a stand alone purification plant.

Why can an enterprising merchant not buy up loads of purification plants and have them built at every type C starport?

 

[AnotherDilbert]

Also: For my "taking off and landing and taking off once more" notion, I see the streamlined ships similar in maneuverability to Space Shuttles... that is, not a lot. They get lift to get into orbit, and they get lift to ascend safely. But they don't fly like airplanes.

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.

 

[AnotherDilbert]

Is that worth it? Getting by on unrefined fuel--which is a hell of a bonus, evaporating a lot of operating expense. But, a 5% reduction in cargo capacity, or the loss of 2-3 passenger staterooms, does eat into a ship's profitability, trip after trip, jump after jump.

~45 dT of refined fuel is kCr 22.5, unrefined fuel will save you kCr 18 per jump, every jump. ~8 dT of cargo will make you kCr 8 per jump if you fill the cargo hold, which is not guaranteed.

Yes, it is generally worth it.