new jump fuel

[mad13142000]

Once again...Not comparing THINGS, comparing tech now, to tech 3 thousand, 5 hundred YEARS in the FUTURE....

50 years prior to Saturn V, nobody thought there would be something like the Apollo Rocket...Jules Verne thought about shooting people to the moon in a canon. (or whoever it was...) But in less than 1/35th the time from now till Traveller, man went from not imagining flight by man, to men on the moon...
I got no problem with my far trader having liquid H tanks a few feet away from the galley...

-MADDog

 

[Anthony]

Originally posted by MADDog:

We are talking about 3500 years in the future. If Air Products can drag semi-tankers full of liquid Hydrogen around today, surely my far trader can have a tank for it in the year 5400...

Bear in mind that Traveller tech doesn't follow any remotely realistic progression; in many ways it's not even up to modern standards, in other ways its incredibly advanced or simply physically impossible.

It's a game. Canon says you can have tanks of liquid hydrogen, so you can. This doesn't mean you can have tanks of compressed hydrogen, or tanks of hydrogen slush.

 

[mandelkubb]

Originally posted by MADDog:

If the Saturn V could carry the stuff 30 years ago,

The Saturn V used LOX and kerosene, IIRC (because of the higher energy content in kerosene compared to LHyd). The space shuttle uses LOX and LHyd.

 

[Zutroi]

Originally posted by mandelkubb:
</font><blockquote>quote:</font><hr />Originally posted by MADDog:

If the Saturn V could carry the stuff 30 years ago,

The Saturn V used LOX and kerosene, IIRC (because of the higher energy content in kerosene compared to LHyd). The space shuttle uses LOX and LHyd. </font>[/QUOTE]Close, but third stage and the Command and Service Modules used cryogenic hydrogen and LOx, IIRC

 

[mandelkubb]

Originally posted by Zutroi:
Close, but third stage and the Command and Service Modules used cryogenic hydrogen and LOx, IIRC

You learn something new everyday.

 

[mark_rotteveel]

Crikey! I've read through this one, and reckon I got about 50% of it

I'm not sure about compressing H or CH4 or whatever, but I've had a question that's in a similar vein... I'm having great difficulty phrasing this one, so pleas bear with me if I ramble on

A 1.8L engine from a car, say, 30 years ago, delivers less power, and is less fuel efficient that a similar engine from today. So, that being the case, wouldn't this also apply to the Jump drives? IMTU the TL of the jump drives affects their fuel consumption, and size. I normally say that over TL12, they use/weigh about 10% less per TL. So, even though the fuel is similar, you get better 'mileage' from it.

I have abosluetly no scientific backup for this whatsoever, but then again, I don't own a Jump drive either

What does everyone think? (be gentle)

 

[Granpafishy]

Originally posted by Rotters:
A 1.8L engine from a car, say, 30 years ago, delivers less power, and is less fuel efficient that a similar engine from today. So, that being the case, wouldn't this also apply to the Jump drives? IMTU the TL of the jump drives affects their fuel consumption, and size. I normally say that over TL12, they use/weigh about 10% less per TL. So, even though the fuel is similar, you get better 'mileage' from it.

I have abosluetly no scientific backup for this whatsoever, but then again, I don't own a Jump drive either

What does everyone think? (be gentle)

That is a good thought.
It's close to something I have started doing with the jump drive. Depending on TL change the Jump Drive size. For a TL 13 ship with J2, I would divide the jump drive size by the number of jumps at that TL and multiply the result to get a J2 drive. It shows the increase effeciency of higher tech levels.

 

[mark_rotteveel]

For a TL 13 ship with J2, I would divide the jump drive size by the number of jumps at that TL and multiply the result to get a J2 drive.

Yeah, that works, too.

Would you do the same for the ships computer?

 

[Uncle Bob]

As long as the basic technology doesn't change, you are looking at not-very-drastic changes in sizes and weight. An internal combustion engine of 2001 (TL8) is about 20% more powerful and efficent than a TL5 engine of the same size from 1955.

IYTU you can make changes, but it is not a logical necessity. Besides, the J-drives are a trivial part of the engineering percentage.

Don't get me started on Traveller computers. *twitch*, *twitch* growl, *foam*. I treat the "computer" percentage as a sensor suite. Since long range passive senors require a given aperature to work, I assume the weight for a given performance won't change.
[Translation: a big honkin' telescope will always weigh a lot.]

Only the first stage of the Saturn V was kerosine powered. The second stage (SII) and third stage (SIVB) used LH2/LOX J2 engines.
Using 1960s technology tankage runs about 10% the weight of the fuel. Long term LH2 storage was addresed in the 1970s with the early Mars mission studies.

 

[Granpafishy]

Yeah, that works, too.

Would you do the same for the ships computer?

That is the one area I'm not sure about. I use T4 primarly and I have not seen listings for the "computer" in any of the three constructions books (MB, Starships, FFS2). They do have basic controls which vary with the size of the ship but not a computer. Given that the size of the "workstations" of the bridge are a full displacement ton each and you are required to have 4 or 5 (Pilot, Nav/Astro, Gunnery, Elcetronics, Engineering[can be 1/2 size if you have a workstation in the engineering space]), I think that MWM used that as exchange for the computer.

 

[Granpafishy]

Originally posted by Uncle Bob:
IYTU you can make changes, but it is not a logical necessity. Besides, the J-drives are a trivial part of the engineering percentage.

That is very true, but when you putting a ship together, every extra cubic meter counts.

 

[mark_rotteveel]

I use T4 primarly and I have not seen listings for the "computer" in any of the three constructions books (MB, Starships, FFS2).

Oh, ok. Not familiar with T4, Granpafishy

Besides, the J-drives are a trivial part of the engineering percentage.

As Granpafishy said, very true. But the fuel they use definitely isn't. I use the CT shipbuilding rules, and always seem to end up with this sort of Fuel-Tank-with-the-odd-stateroom-inside ship. Therefore, I make 'minor adjustments'

(no offence, Mr Miller, if you're reading..... and don't tell on me, Hunter

)

 

[mandelkubb]

Originally posted by Rotters:
I use the CT shipbuilding rules, and always seem to end up with this sort of Fuel-Tank-with-the-odd-stateroom-inside ship.

The fuel consumption rules for PP:s in CT is a bit strange, for example; a certain type of PP will need 60 tons of fuel in a 100-ton ship but only 10 ton in a 600-ton ship. This is becuase JD, MD and PP use the same table to decide various values (Acc & Jump vs. Pn).

How have you dealt with fuel consumption (MD/PP), if I may ask?

 

[Andrew Boulton]

I use T4 primarly and I have not seen listings for the "computer" in any of the three constructions books (MB, Starships, FFS2).

FF&S2 is actually one of the few Trav books I have handy. Try p69. Where it says "Computers".

 

[Granpafishy]

Originally posted by Andrew Boulton:

FF&S2 is actually one of the few Trav books I have handy. Try p69. Where it says "Computers".

There it be in plain sight, I remember looking at it too Though the sizes are not the big. But as I said, I not sure about the sizes for the versions.

 

[spank]

A 1.8L engine from a car, say, 30 years ago, delivers less power, and is less fuel efficient that a similar engine from today. So, that being the case, wouldn't this also apply to the Jump drives? IMTU the TL of the jump drives affects their fuel consumption, and size. I normally say that over TL12, they use/weigh about 10% less per TL. So, even though the fuel is similar, you get better 'mileage' from it.

I worked up a table for use IMTU using 2 basic assumptions,

1) a engine jumping below it's maximum potential can do so more effciently than one jumping at it's capacity {ex. a jump-4 engine jumping at jump-2 will use less feul than a jump-2 engine at jump-2} I represent this as a 10% saving in the jump cost for every level the drive exceeds the jump.

2) an engine can make a jump faster rather than more effciently each day save adds one to the jump level{ex. a jump-6 engine can make a jump-4 in only 5 days, but spend feul as if it where a jump 6}

In example 1 a 100 ton ship would spend 20 tons of feul to make the jump under my rule it would spend 16 tons or {20 tons - 20%} The extreme of this example is a jump-6 ship traveling 1 parsec. it would spend only 10 tons or 50% of the required feul.

example two's extreme would be a j-6 ship making a j-1, it could make the jump in as little as 2 days. Interstingly someone pointed out to me this rule duplicates the X-boats

 

[Whipsnade]

spank wrote:

"example two's extreme would be a j-6 ship making a j-1, it could make the jump in as little as 2 days. Interstingly someone pointed out to me this rule duplicates the X-boats"


Sir,

Huh? It what way does it 'duplicate' the X-boats?

I suppose your homebrewed jump6 craft could manage to equal the ~3 parsec per week interstellar speed of the X-boat network by jumping one parsec every 2 days, but I can't quite see how that would be preferable.

For starters, your homebrewed craft is using it's jump drives three times as often. That raises all sorts of interesting misjump and maintenance questions. Then there is the additional expense of a jump6 drive and its attendent power plant over the normal jump4 suite. Also, have you looked into the military consequences of this?

I love homebrewed rules, use them all the time. I also try and work out most of the ramifications involved too.


Sincerely,
Larsen

 

[far-trader]

Originally posted by Larsen E. Whipsnade:
spank wrote:

"example two's extreme would be a j-6 ship making a j-1, it could make the jump in as little as 2 days. Interstingly someone pointed out to me this rule duplicates the X-boats"


Sir,

Huh? It what way does it 'duplicate' the X-boats?

Good day Larsen, I think this is in reference to a remark I made but can't find the post now, must have been in a different topic. Anyway iirc what I was commenting on is that a standard J4 X-boat was described early in CT as making jumps in about 4 days rather than the 7 standard and that with spank's system this could now be explained as (some contractor's exageration of) the J4 performance over a 1 parsec jump (kinda like a certain Captain's bragging claim about his ship's speed ) Naturally not many (none?) places on the routes are J1 so that contractor's name is mud, but they did get a very lucrative contract

Just an observation and no desire to change anything in canon, a little handwave to explain the past with his new wrinkle. The next thing I want to figure out is how it was possible to (as claimed in some other publication that I have at the moment mislaid) to send an X-boat on its next jump in a few minutes (I forget the exact number). So far the only way I can see it is by introducing a new (perhaps experimental, and I think it has been suggested by others too) practice of using drop tanks (or more properly, Fast Fuelers) for X-boats in some systems.

A Fast Fueler would be a high G small craft (perhaps a 95T shuttle conversion) that would race up to incoming X-boats, perhaps swap pilots while dumping data and packages and hooking up the fuel dumps. Then like a drop tank it provides the fuel for the X-boat. Unlike the drop tank, since it is powered, it moves away to reduce the jump error inducing chance of nearby mass when the ship tumbles into the void. Just an idea, not yet fully fleshed out.

 

[spank]

yes,
That was from you.


I personally picture the X-boats as a 2 part ship, one part with the cargo,data,and crew, and the other as nothing more than a large feul tank that is jetissoned and piloted back to refuel by one of the crew. A new feuler section is waiting, problaby with supplies, data and cargo. It is piloted into place and then the boat is gone again. Jump engines are in the feuler section so they can be serviced while the section is being refueled.

 

[Andrew Boulton]

I personally picture the X-boats as a 2 part ship,

No, it's simpler than that - there are two ships. The first jumps insystem and transmits the data to the xboat station, which then retransmits it to a second xboat. The second ship immediately jumps outsystem. The first is serviced, refuelled, and waits for the next boat to arrive.

See here.