Power and Propulsion in T5

[robject]

Originally posted by atpollard:
</font><blockquote>quote:</font><hr />Originally posted by robject:
And since they can use Fusion+ power, you still have a yearly refuelling schedule.

Can T5 still be called Traveller if you are not arguing about the fuel consumption of the Fusion power plant, its efficiency/energy output and what the extra hydrogen is REALLY used for?

I see some things that have surely stirred my curiosity. Any word on DEEP SPACE propulsion? (like what happens past 1000 diameters). </font>[/QUOTE]Yes, but first:

Power

After a certain size of craft (a hundred tons or two or three...), it becomes less desireable to use a Fusion+ plant; the starship power plant, aka the Power plant, becomes more pleasing to more naval architects. It packs more bang for the ton, and the larger the drives, the greater comparable advantage the Power plant has.

As we all know, the Power plant leaks fuel, and is expensive, and requires drive techs on board. It also has a minimum size of 4 tons. Those reasons are why most of my small craft generally make do without.

So much for the P-plant and F+plant. There's also Antimatter power, Collectors, and Trickle plants. I'm fuzzy on exactly how they all work, and I know there have to be TL minimums for each plant -- I just don't know what they are.

Propulsion

There are half-a-dozen ways of getting around. If you've checked out my smallcraft, you already know about the G-drive: a sealed, gravitic drive with an integral Fusion+plant and a 100-diameter limit. And you probably already know about the M-drive, with its 1000-diameter limit.

Using other Traveller rules, you can also infer Lifters, which are even more primitive gravitic drives, with a 1-diameter limit and a very low horizontal thrust. I don't know all of the details about Lifters, except that they can be very small -- i.e. the grav belt has a Lifter as propulsion. Call it nullgrav and you're on the right page.

Past these drive limits, the drives generally stop working. The M-drive still has a fraction of push, but its performance just stinks. The G-drive has next to no push beyond 100D, and Lifters have none at all past 1D.

If you want to push your way through deep space, I don't know what you're going to have. I was thinking that this could be a gap to fill, assuming the Near-C-Rock problem can be ignored. There is a HEPlaR drive, which is absurdly small, highly effective, but has a high fuel consumption rate, so I would hesitate to call it an effective deep-space drive. There's also a Rocket -- at least there was -- but I haven't seen details on it, and it appears to have been shelved.

Another drive that was shelved was an inertialess drive. Obviously it would've been a very high-tech device.

 

[Andrew Boulton]

Rather than g-drive and lifters, stick with T4's contragrav.

 

[robject]

It only struck me recently how much Traveller has evolved away from T4. It's more than an accumulation of tweaks, and hasn't looked like T4.1 for some time now. It's been incorporating more ideas from earlier rule sets, even though it remains based on FFS2.

This shows up in power generation and propulsion.

 

[Andrew Boulton]

That could be very good or very bad.

 

[atpollard]

A quick question to the general community, which drives would work in our asteroid belt? Is it more than 1000 solar diameters from the sun? Would part of it be within 100 diameters of Jupiter? It could create some interesting dynamics for asteroid mining - like the need for miners to follow Jupiter or be stuck in that part of the asteroid belt until Jupiter comes around again. (I assume that it is more than 1000 diameters from Mars.)

 

[Andrew Boulton]

1000 solar-d is roughly 10AU, or just past the orbit of Saturn.

 

[atpollard]

Originally posted by Andrew Boulton:
1000 solar-d is roughly 10 AU, or just past the orbit of Saturn.

Thanks.

So a G-drive is good ANYWHERE from the sun to roughly Earth orbit and M-drive would work ANYWHERE from the sun to roughly Saturn's orbit (in our solar system).

That gives me a pretty good feel for the new drives. That 100 diameter from the sun would also apply to the old Striker/MT grav drive, so an air raft could travel from the surface of the Earth to Venus or Mercury. Wow, I never realized that before.

 

[robject]

Right -- assuming the Striker/MT grav drive corresponds to the G-drive. By Traveller 5 reckoning, the standard air/raft probably has lifters, but there's nothing stopping one from having a G-drive. For example, a half-ton, 4Mj drive could propel a 4-ton enclosed air/raft at 1G.

 

[koza]

Ok, I have a stupid question, but I need confirmation.

Do the new drives for T5 create true velocity? I am 99.9% sure they do, but I am just making sure.

The reason I am asking is for the sake of "golf balling" a trip.

I got that term from NASA - when they compare shooting a rocket to the Moon being comparable to driving a golf ball - no continuous thrust; you create your velocity then drift to your destination for final maneuvering.

Example: You have jumped in and are refueling at Saturn. You get a signal GK from a ship near Neptune. You could micro-jump to Neptune, but the jump takes between 6-8 days (assuming T5 still uses the old jump rules). Your navigator states that the position Neptune is to Saturn at this time means a trip through N-Space would be faster.

Assuming the answer I am looking for is "yes," You could golf ball your way to Neptune orbit and, once you get to within 1000 diameters of the world, you could maneuver normally again.

Because of this, whole solar systems are still pretty much accessible, even at the outer orbits (assuming there is a significant gravity well out there).

 

[Cryton]

interesting so far. But why the need for SO many types of drives? Isnt one or two trypes of sci-fi propulsion enough?

 

[robject]

Originally posted by Kozaenrro:
Ok, I have a stupid question, but I need confirmation.

Do the new drives for T5 create true velocity? I am 99.9% sure they do, but I am just making sure.

The reason I am asking is for the sake of "golf balling" a trip.

[...]

Assuming the answer I am looking for is "yes," You could golf ball your way to Neptune orbit and, once you get to within 1000 diameters of the world, you could maneuver normally again.

Because of this, whole solar systems are still pretty much accessible, even at the outer orbits (assuming there is a significant gravity well out there).

Yeah, that's right. If a ship is unable to jump to its destination, it could accelerate, coast awhile, then decelerate at the target.

 

[robject]

Originally posted by Cryton:
interesting so far. But why the need for SO many types of drives? Isnt one or two trypes of sci-fi propulsion enough?

Yes, one or two types is plenty.

One of the types here -- the G-drive -- adds a decision point to craft (smallcraft, mainly): maintenance-free behavior versus relatively low performance.

Another type -- HEPlaR -- has been around since TNE at least, and represents the reaction drive: accelerate anywhere, but carry lots of fuel.

The other drive types have already existed for Traveller since the beginning: for example, lifters are nothing more than nullgrav modules.

So, in summary, the reason for several drive types is where important decisions generally rest, and where vehicle divisions also tend to rest. Offhand, I can only think of these criteria:

Is the craft used for (somewhat low) orbital service?
Is the craft used for jump-service?
Does the craft require low maintenance?
Is the craft used for inner-system service?
Is the craft required to move anywhere?

 

[robject]

This post is for Wol/Colin, who had a question about maneuvering in T5.

The Maneuver Drive, which is mostly reactionless, is alive and well, and lives alongside HEPlaR. Each has benefits and tradeoffs. Choose wisely.

Yes, the Near-C-Rock problem doesn't go away. But my problem is with vectors, which makes CT relatively unfriendly for miniatures. And vectors are a problem with any newtonian models.

All that tells me is that some kind of rule is needed that (1) implicitly limits thrust on a miniatures map, or (2) agility rules that handwave most of the vector issues away, so that a ship with enough agility can mostly ignore vectors.

 

[Wol]

A couple of things...
Hohmann transfer orbits (golf ball shots) are used because they are energy efficient not because they are quick. If we had the power and antigrav of traveller we would not bother. It's 5 days to the moon with a minimum energy shot. That is the way of current rocketry!

BL played well with Heplar and the associated limited fuel. I thought so.
Structural limits (stressing to XGs) and contragrav provide limits to manouvarability but enable very large changes in vectors. I think long turns help here (1/2 hour in BL?) I must get it out again.

I no longer recall - what are the limits on manouver drives?

BTW If they are to be used, how about a massive drain on the power plant (needed to harmonise the threepdanglers in manouver mode) whch consumes fuel at about the same rate as Heplar.

 

[Maccat]

I like the Heplar drives from T4, especially for low TL/early craft, and they served well to get beyond that 100d stuff, fusion rockets too for that matter for added power output (expensive though!). Biggest lack i feel is a proper Solar Power, saw some LBB2 derived from MT, prices (and tonnages) seem out of whack as a HG TL7 (solar) power plant is .04 mass at 3MCr/ton, no? Scaled-up missile propulsion from the missile supplement as "drives" even works lol. What about capacitators as power plants, btw. I always thought of the X-boat with no power plant as being driven by a big bank of capacitators, charged up by the XBoat tender, mostly to save on fuel usage. Or maybe a power plant 2, and capacitators for 10days at 2ep.
I HOPE they do not eliminate the standard drive sweet spots in LBB2 of exceeding the standard TL requirement in HG for jump for "small" starships, i see those drive and hull combinations as being essential to allow lower TL worlds *some* ability to operate in the greater Imperium.
the seeker/scout/courier is TL9 J2, Xboat TL9 J3, TLA J4 (/4 computer)(just add a 15t drop tank sheesh), far trader TL9 J2, SubD Liner TLB J3, Merc Cru TLC J3, patrol Cr TLA J3, Lab TL9 J2, Safari TL9 J2, Corsair TLA J2, that's 10/12 (free/fat trader) VERY classic ships which are impossible using HG (ok though because LBB2 allowed yay!)(or T4, no?)
The trend like in T4 was now they are TLB/C ships say. Rather than try to shoehorn the vast majority of classic traveller ships by upping their TL requirements (so much for frontier / backwater ship refits), let them be, allow them, make these "new & improved" rules incorporate those ships as legal, no?
It's as easy as having "special" jump drives, extra massive, ala LBB2 standards for those sweet spots, which btw aren't that many anyhow, tonnage limited for good measure. As an example i just posted a TL9 J3 LBB2 "liner". The trend seems to have been upping the TL, or having all design be at TLF, which breaks down horribly (especially *economically*) at lower TLs. If i roll up a TL9 world, they will have starships (maybe), but they sure won't if nothing is economical/profitable, at least in classic traveller. The only large power plants, and low output/high cost of them, plus (extreme!) power requirements (escpecially sensors in T4)(weapons too for that matter, and...) dictated large extremely expensive ships at lower TL, hence unprofitable. From the previous posts i guess i'm missing something of what is intended for this mongoose traveller, there is nothing that i've found on their site regarding ship design or economics.

 

[robject]

Wow Maccat, that's a mouthful of good observations and questions you made. Can I ask that, next post, you sort of divide up your text into smaller paragraphs? Easier to read that way!

You're right - photovoltaics aren't in the draft. But I agree that they should be. As I recall, they were pretty low powered, but great for remote installations.

Accumulator banks for power is there, included in power packages called "Collectors". They are exotic, and probably can only be charged up in proximity to a star (i.e. and not by a power plant). Their primary example of use is the ANNIC NOVA.

The drive potential table has been modified, due to the limitations of the original one. However, the low-end drives are unchanged, with the result that the small adventuring starship designs in CT are compatible, and in fact some of them are nearly identical. The reason this is so is that T5 has more choices than Book 2 in ship design, so that contents can be defined a bit better, and volumes can be juggled around.

I never thought about it, but I suspect the Jump-1 ships could still work at TL9. I'll have to see. The major difference between TL9 and TL12 at this point are the quality of sensors and weapons.

And of course, until the draft is publicly available, everything I just wrote about is subject to change by Marc at any time.

 

[robject]

Rather than g-drive and lifters, stick with T4's contragrav.

The way I'm thinking of it, that's more or less what they are.

 

[Maccat]

Right I'll try n break it up more in the future lol

...Not J1 at TL9, but say an XBoat w/ J4B drive (would be J3 at TL9 due to no /4 computer [/3bis anyone?]), a 100t J2 s/c at TL9, Far trader J2 200t TL9. There's a very small set using the low(er) end drives to enable "beyond HG TL limited" jump capability (is TL standard drive capability vs computer model in LBB2). Specifically, for scouts, mailboats, or commerce patrol escort craft (and pirates!) they are the only thing lower TL worlds have. Best example that comes to my mind is a lower TL society being able to build a small J4 or 2xJ2 trader to participate in the xboat route trade. In a bunch of the systems (say T4 pocket empires) (or HG for that matter) the higher TL societies can over-dominate unless lower TL have some (minimal, small) higher jump capacity, to my mind.
Thanks for your reply there, good to hear some of what's coming in the new system!

Below is a table of the specific "sweet spot" jump capabilites and TLs i'm talking about. These are jump capabilities by ship tonnage max at various tech levels using standard LBB2 drives, that exceed 'TL limited' (HG) jump capability. It allows things like a J4 600t sub'd trader at TLC to follow the xboat routes. TLA could have a 600t 2xJ2 Sub'd trader doing the same, just slower! A lot of them can't carry the neccessary fuel anyhow, but might be possible using drop tanks if the capability were absolutely neccessary.

TL 9 10 11 12 13 14
J2 1,2,400t 600, 800t
J3 100,200t 400t 600t
J4 100,200t 400t --- 600t
<lacking computer TL9 J4+, but could build it go look for a /4 upgrade>
J5 100t 200t 400t --- 600t
J6 100t 200t --- 400t 600t ---

Hope to hear more as this rolls along, many have strong opinions so I don't envy you that aspect of it, but it's all because we like the game (whichever version). please please please double check the designs, and get a standard new-rules-legal version of all the classic ships, at a minimum for my vote. (I want a legal xboat! [150t J4C works heheh] I want a legal Lab ship!)

Only other thing i can think of is a wilderness life support recharge idea, hopefully tied in with belting and ice. Using LBB2 straight O2 tanks and water tankage, comes to .75t for 1pp 2 weeks. Idea is you could land on a world, fill your tanks with air, load up some water, hunt/gather for the food you need, and then carry on extended (Scout) operations in the 'wilderness' / backwaters, or recovering from a misjump.
Something for explaining multimillion asteroid belt populations, on-board hydroponics say ciould be very useful too, otherwise i'll build a ship to charge them an arm and a leg for it or they die and retire a milklionaire (sigh).

 

[robject]

Assuming there's a number of standard, off-the-shelf drive units that are mass-produced by high-tech industrial or corporate (or droyne) worlds, I think it's very reasonable that low-tech worlds should be able to buy these drives, complete with "plug them in" instructions for their engineers. They may not be able to tinker with them, but they should be able to at least replace units, for instance for upgrades.

 

[parmasson]

I think the reason for the different types of engines is to keep a separation between the different roles of craft. Starships/non jump ships/planetary craft.

Parmsson aka Kurega Gikur