"Fuel Usage in Classic Traveller?" Topic

Does anyone know of a formula, or formulae for Classic Traveller vessels/fighters, for maneuver (sublight) engines?

I don't recall seeing that, other than the book mentions the tonnage given is usually enough for X number of weeks, at normal usage rates. Normally, about 4 weeks, for the smaller vessels, e.g. 100 – 400 ton class.

I suspect in combat, or in a pursuit scenario, a lot more might be used.

Thoughts, e.g. amount in tons, or a percentage of capacity used per hour of thrust (possibly more at higher thrust levels, too), etc.?

The Classic mode assumed that you could be under thrust the whole month, since the same fuel number was used for both starships and non-starships.

Using CT High Guard and MegaTraveller as basic guides, weapons and maneuver are the power hogs. Everything else is chump change.

Hmmm, given how many tons of fuel a relatively small, modern day fighter can burn in just a few minutes, that doesn't seem quite right, especially for smaller vessels with limited fuel capacity, especially when running at higher G thrust.

If you really want to go into fuel use in detail then It`s worthwhile going into the later versions of Traveller, particularly the New Era material which, if anything went overboard with that sort of detail.
With the earlier versions of the rules the assumption was "its fusion power and it works".
It was the later editions that retconned things a bit with Grav and HEPLAR thruster technology.

The thing about the original vector based combat system was that to keep things simple in the pre personal computer era a lot of things were left undefined.
Very few people actually used it, preferring the more abstract High Guard system or the Mayday box set game to resolve combat. This meant that the original Book 2 rules got rather overlooked and remained undeveloped, the lack of usable models for the stock ships didn`t help either which was rather a pity.

If you actually play it then you realise rather quickly that things are happening more in "knife fight" range (I.E INSIDE one Mayday hex!) scalewise when compared with the more commonly used systems and it worked pretty well for small individual ship Vs ship combat.
One thing I`ve noticed though over the years I`ve been playing space warfare games is that people`s preferences seem to lean more to Big Ship/Big Naval battle type games, something the Book 2 system couldn`t handle.

You are probably assuming reaction engines, instead of magical grav tech.

TNE uses fuel as reaction mass. Fuel usage for thrust that is still miraculously efficient is still taking too much of the ship to allow classic Traveller ship designs. TNE bent prior ship design severely.

If you want to go that route, it will quickly stop being Classic in many ways.

Seriously over-thinking CT.

Science Fiction Handwavium…

With TNE what you had to do was dig out the Fire, Fusion and Steel supplement (enough formulae to keep the most dedicated number cruncher happy!) and redesign the standard ships to TL15 Grav technology standards.
If you did that it was interesting how even a basic ship like the Type `A` jumped in performance as a result, closer to the CT version.

The assumption was in the game from quite early on that the basic ships were built as standard designs using `off the shelf` modular components built to the highest tech readily available, imported from `off world` if they couldn`t be built locally.

I wouldn't spend a lot of effort considering modern fighters. Remember that they have to deal with gravity and friction, two things in short supply in space.

CT ships do not use maneuver fuel
fuel is only used by the jump drive and power plant

maneuver drives get their power from the power plant

effectively power plant fuel usage rules
assume full thrust at all times

check JTAS 15 for rules on 'powering down'

Just to try to synthesize what others have done a good job expressing:

1. CT drives are reactionless. Eliminating the need for reaction mass vastly reduces the amount of "fuel" that you consume.

2. CT drives are powered by fusion power plants. Fusion requires ridiculously small amounts of fuel for very large power outputs.

One of the logic problems with CT (well, all versions, really) is the extraordinarily large power consumption of jump drives. If all of the fuel is used for power, the ships should simply evaporate due to the waste heat. If most of the "fuel" is actually used as coolant, there doesn't seem to be nearly enough coolant.

The end result is that you don't need to worry about fuel consumption in CT. Oddly, though, Mayday has fuel limits for small craft, and those limits are prohibitively low in most cases.

did some digging
77 edition book 2

All non-starships consume fuel at the rate of 10 kilograms
for each G of acceleration for ten minutes
regardless of mass or cargo carried

the listed fuel tankage for the various small craft
vary significantly between the 77 and 81 editions

"One of the logic problems with CT (well, all versions, really) is the extraordinarily large power consumption of jump drives. If all of the fuel is used for power, the ships should simply evaporate due to the waste heat. If most of the "fuel" is actually used as coolant, there doesn't seem to be nearly enough coolant."

in some versions of Traveller
a portion if jump fuel is vented during jump
and used as ablative shielding
against the incursion of jump space into the ship

Thanks for all the replies and info.

That 10 kilos number will be especially useful, if/when I desire to conduct a drawn out duel, or need to conduct some sort of space pursuit.

May round that off to 60 minute, or 30 minute turns, just to make it a little more manageable.

Do the fuel usage stats/tons carried on board the vessels correspond to one another, once the turn time differences are factored in (e.g. are they at a constant formula change to one another, e.g. still maintaining the 60 kilos/hour usage, for the differing turn lengths – not sure which edition of the rules I have)?