Pondering starship evolution

[Spinward Flow]

a 180 ton (9x 20 ton berth slots) internal hangar bay

I'm now thinking of doing something that involves a bit of syncretism between the different versions/editions of Traveller that has been published over the years.

LBB5.80, p32 states:

Small craft are carried at their own tonnage on ships 1000 tons and under; they require tonnage equal to 130% of their mass within the hull of larger ships. The cost is Cr2,000 per ton.

Ships may also carry non-starships greater than 99 tons, or even other starships, provided proper arrangements are made. Big craft require tonnage equal to 110%of their mass in the ship; the cost is Cr2,000 per ton.

However, when I'm drawing deck plans, I'm running into a problem that creates a problem of intellectual honesty.

The sub-craft that I'm putting into the internal hangar spaces aren't being vacuum shrink wrapped by the walls of the hangar bay(s). The "packing efficiency" of sub-craft to hangar space is not 100% on the deck plans. This is creating a tension with my intellectual honesty.

Later editions of Traveller moved to a system of "all sub-craft cost 110% of displacement" ... including small craft ... and eliminated the over/under 1000 tons dividing line for allowing small craft to be berthed internally at only 100% of their displacement.

I'm now thinking of adopting this 110% displacement for small craft notion for my Long Trader design, even though LBB5.80 says otherwise. Among other things, doing so would solve a few "compatibility issues" with later editions of Traveller if someone wanted to port the design out of CT and into a different edition (such as Cephus and/or Mongoose). This would apply to both internal and external loading, so I'm going to need to recalculate a few things on the Boxes and Pods, too ... along with how much external load capacity there actually is (spoiler alert: 600/1.1=545.45 tons

The fun thing about taking that stance is that it means that 9x20=180 tons of sub-craft capacity now requires 180+18=198 tons of displacement be allocated to the hangar bay(s) on the naval architect spreadsheet. Add in +2 tons to that (for a nice round 200 tons of hangar bay) and you've got a 200 ton capacity Collapsible Fuel Tank IN the hangar bay space when the hangar bay has no small craft loaded into it.

Now, why would an extra 200 tons of fuel (in a Collapsible Tank) be useful?
Simple.
J1 @ 1000 tons combined displacement = 100 tons of jump fuel

In other words, 200 tons of fuel reserve in a Collapsible Tank, plus 110 tons of fuel in the integral main fuel tanks means ... J1+1+1 is possible @ 1000 tons of combined displacement with external loading of sub-craft owned by the operator PLUS additional Boxes and Pods owned by third parties wanting to charter a share of the external load capacity.



I'm going to need to run some more theoretical simulations for load combinations (both internal and external) to find the right "balance point" prompted by this paradigm shift in the computation of small craft tonnage (from 100% to 110%).

I may wind up needing to shoehorn the starship into a 390 ton hull instead ... because 5*20*1.1=110 and since the J2 limit is at 500 tons combined displacement, 500-110=390 tons.

And just for clarity in analysis of alternatives, (16+4*20)*1.1=105.6 and since the J2 limit is at 500 tons combined displacement, 500-106=394 tons.

(1000-390)/1.1 = 554.5454 tons of external sub-craft tonnage capacity
(1000-394)/1.1 = 550.9090 tons of external sub-craft tonnage capacity



(16 + 27*20) * 1.1 = 611.6 tons max external sub-craft allocation @ J1 performance limit
1000 - 612 tons = 388 tons starship hull displacement limit under new small craft tonnage accounting paradigm

(28*20) * 1.1 = 616 tons max external sub-craft allocation @ J1 performance limit
1000 - 616 tons = 384 tons starship hull displacement limit under new small craft tonnage accounting paradigm



I might be able to finesse a way to get down to a 388 ton starship hull without needing to make too many compromises.
Getting down to a 384 ton starship hull though ... ... might not be doable.

This will require some testing and analysis.

 

[Spinward Flow]

I might be able to finesse a way to get down to a 388 ton starship hull without needing to make too many compromises.
Getting down to a 384 ton starship hull though ... ... might not be doable.

Tested.

388 ton starship ... WORKS.
384 ton starship ... DOESN'T ... (too much stuff, cannot compress things any further).

Had to delete all of the vehicle berths along with a few other "nice to have" options that weren't strictly necessary ... along with downsizing the fuel allocation (while doing something clever about it to ensure adequate safety margin) ... so the result definitely FEELS TIGHT(!) ... but it all fits.

Looks like I'm going to be "freezing" the J2/2G Long Trader into a 388 ton custom hull (after flirting with 400 tons).

 

[Spinward Flow]

388 ton starship ... WORKS.

... until it doesn't ...

Did some additional multi-jump endurance stress testing and the results come back ...

... answer ... NO.
Not THAT lucky.

So for the 388 ton option, the endurance margins are just simply TOO TIGHT.
So long as NOTHING GOES WRONG ... you can make it work ... until something goes wrong and you're left with NO MARGIN for errors or mishaps. There's no margin for recovery after an "event" happens.

Yeah ... that's not going to fly ... let alone keep flying through wilderness.







(25*20) * 1.1 = 550 tons max external sub-craft allocation @ J1 performance limit

• External docking points (5): port wing (dorsal+ventral), centerline (ventral), starboard wing (dorsal+ventral)

1000 - 550 tons = 450 tons starship hull displacement limit under new small craft tonnage accounting paradigm

• 55 tons for LBB2.81 standard E/E/E drives (code: 2)
• 110 tons of total fuel: 450 tons @ J2 = 90 tons jump fuel + 20 tons power plant fuel
• 8 tons for TL=10 fuel purification plant (200 ton capacity is minimum)
• 20 tons for bridge
• 4 tons for model/2fib computer

= 55+110+8+20+4 = 197 tons
450-197 = 253 tons available

• (11*20)*1.1 = 242 tons of hangar volume that can accommodate 220 tons of small craft hulls (combined)
  1. Escort Fighter
  2. Stateroom Box
  3. Stateroom Box
  4. Stateroom Box
  5. Laboratory Box (life support)
  6. Laboratory Box (life support)
  7. Laboratory Box (life support)
  8. Environment Box
  9. Environment Box
  10. Cargo Box
  11. Cargo Box

Hmmm ... it's close, but not exactly where I would want it for optimal flexibility and efficiency of displacement options.




(16+(2*20))*1.1 = 61.6 ≈ 62 tons (Escort Fighter and 2x Boxes can be docked externally and retain J2)
500-62 = 438 tons starship hull displacement

• 55 tons for LBB2.81 standard E/E/E drives (code: 2)
• 108 tons of total fuel: 438 tons @ J2 = 87.6 tons jump fuel + 20.4 tons power plant fuel
• 8 tons for TL=10 fuel purification plant (200 ton capacity is minimum)
• 20 tons for bridge
• 4 tons for model/2fib computer
• (11*20)*1.1 = 242 tons of hangar volume that can accommodate 220 tons of small craft hulls (combined)
  1. Escort Fighter = 16 tons
  2. Stateroom Box = 20 tons
  3. Stateroom Box = 20 tons
  4. Stateroom Box = 20 tons
  5. Laboratory Box (life support) = 20 tons
  6. Laboratory Box (life support) = 20 tons
  7. Laboratory Box (life support) = 20 tons
  8. Cargo Box = 20 tons
  9. Cargo Box = 20 tons
  10. Environment Box = 20 tons
  11. Environment Box = 20 tons
• 1 ton for 100 tons capacity Collapsible Fuel Tanks

= 55+108+8+20+4+242+1 = 438 tons

1000 - 438 = 562 / 1.1 = 510.9090 ≈ 510 tons of external load capacity for small craft tonnage
(25*20)*1.1 = 500 tons of small craft tonnage

• External docking points (5): port wing (dorsal+ventral), centerline (ventral), starboard wing (dorsal+ventral) = 5x Boxes @ each docking point

Alright, that looks a good deal more promising.

One of the design points that I'm liking about this (oddball) 438 ton hull is that you get what amounts to 11x standardized 22 ton hangar cells that are all interchangeable with each other which can each accommodate a 20 ton Box. This also means that there is a 2 deck high stack of a single line of 5x Boxes long in the aft hangar bay, with an extra 22 ton hangar cell forward on the main deck. Because the form factors are all the same for each and every single hangar berth, the Escort Fighter can launch and recover through a dorsal clamshell door and dorsal clamshell doors over the aft hangar bay would permit the Escort Fighter to descend INTO the hull silhouette of the starship to dock with and "sky crane" VTOL lift any 20 ton Box (5G for 1, 4G for 2) or 80 ton Pod (2G for 1) that is being berthed in the aft hangar bay space(s). Would still have an aft door for the aft hangar bay, but now rather than being hinged vertically (on the sides) it would be hinged horizontally (top/bottom) so as to be able to split open the aft bay doors and use the starship's landing gear to "kneel/incline" the ship's hull fore/aft in such a way as to use the aft door as a loading ramp into the aft hangar bay for roll on/roll off loading and unloading by ground crews.

J2+2 capability would simply require moving the Escort Fighter and 2x Environment Boxes outside for external docking, bringing the combined total tonnage for drive performance purposes up to 438+(16+(2*20))*1.1=499.6 ≈ 500 tons.
J2 @ 500 tons requires 100 tons of jump fuel.

With 3 of the 11x 22 ton hangar bay berth slots (that can accommodate 20 tons of small craft each) "empty" that's at least 60 tons of hangar bay accommodation space not being used. Open the doors on the 2x Cargo Boxes and let them get filled up with Collapsible Fuel Tank fuel instead of actual cargo (trading ticket revenues for additional fuel capacity) and now you've got 100 tons of hangar bay accommodation space that can be "spent" on filling up a Collapsible Fuel Tank to the 100 ton capacity limit.

1. J2 @ 500 tons = 100 tons of jump fuel. After breakout, during 16 hour routine maintenance checkups, pump the 100 tons of fuel from the hangar bay into the integral main fuel tanks. Move Escort Fighter and 2x Environment Boxes back into the internal hangar bay before jumping again.
2. J2 @ 438 tons = 87.6 tons jump fuel.

Net yield: J2+2 with 7 high passengers and 40 tons of environmentally controlled cargo capacity.
Not too shabby ...

Still a bit "oversized" in some respects.
I'll keep analyzing alternative "jhenga stacks" for this application.

 

[Spinward Flow]

So for the 388 ton option, the endurance margins are just simply TOO TIGHT.

Hooray for (realizing that I'd made a) miscalculation!

The 388 ton option actually DOES have sufficient endurance for not only a double jump (J2+2) but even a triple jump (J1+2+2) if you ... finesse ... the arrangement properly (which I wasn't doing before and have since rectified my error).

That means that a 5 parsec unrefueled range @ 388 tons of starship, in 3 jumps ... compared to the 5 parsec unrefueled range @ 327 tons of starship, in 2 jumps. So if you REALLY need to move 5 parsecs, you CAN DO IT with the redesign.

Additionally, in an attempt to be even more rigorously intellectually honest, I've decided that internal hangar bays, unlike cargo holds, need to "pay a tonnage tax" on their features. Basically, 10 tons of craft (or cargo) capacity in a hangar bay costs 11 tons ... which then neatly solves the problem of "what if you put cargo or a collapsible fuel tank into a hangar instead of a small/big craft?" question.

10 tons of hangar capacity costs 11 tons to the parent craft @ Cr2000 per ton.
So that 10 tons of hangar capacity costs Cr22,000 and 11 tons.

This then means that a 110 ton hangar bay (line item on the naval architect's spreadsheet) can hold 100 tons of cargo (or a 100 ton collapsible fuel tank filled with fuel) or 100 tons of small craft. The math assumptions for it take a little getting used to, but once you recognize what's going on, it works. Even better yet, the exact same mathematical formulation ALSO works for calculating external load capacity in order to pay the 110% "tonnage tax" for external loads as well, just to keep everything consistent (and ensure that there is No Free Lunch™ to be found).

STRICTLY SPEAKING this decision does not perfectly align with RAW in LBB5.80, p32 ... but since the net effect winds up being something of a "penalty" (rather than an exploitative advantage) relative to a fundamentalist reading of CT RAW, I feel a lot more comfortable making this particular concession to compatibility with other versions of Traveller published after CT.



Here is where my "naval architect spreadsheet theorycrafting" has led me to.



(5*20)*1.1 = 110 tons (5x Boxes can be docked externally and retain J2)
500-110 = 390 tons starship hull displacement

388 tons starship hull

• 55 tons for LBB2.81 standard E/E/E drives (code: 2)
• 100 tons of total fuel: 388 tons @ J2 = 77.6 tons jump fuel + 22.4 tons power plant fuel
• 8 tons for TL=10 fuel purification plant (200 ton capacity is minimum)
• 20 tons for bridge
• 4 tons for model/2fib computer
• 200 tons for 200/1.1=181.8181≈181.8 tons of hangar capacity
  1. Escort Fighter = 16 tons (4 tons wasted to achieve form factor commonality with 20 ton Boxes)
  2. Stateroom Box = 20 tons
  3. Stateroom Box = 20 tons
  4. Stateroom Box = 20 tons
  5. Laboratory Box (life support) = 20 tons
  6. Laboratory Box (life support) = 20 tons
  7. Laboratory Box (life support) = 20 tons
  8. Cargo Box = 20 tons
  9. Environment Box = 20 tons
  10. 180 tons capacity Collapsible Fuel Tanks = 1.8 tons
• 1 ton for Cargo Hold containing a 1 ton capacity Demountable Fuel Tank

= 55+101+8+20+4+200 = 388 tons

1000 - 388 = 612 / 1.1 = 556.3636 ≈ 556 tons of external load capacity for small craft tonnage
16+(27*20) = 556 tons of small craft tonnage

1. 388+(16+(27*20))*1.1 = 999.6 ≈ 1000 tons @ J1 = 100 tons jump fuel
2. 388+(16+(22*20))*1.1 = 889.6 ≈ 890 tons @ J1 = 89 tons jump fuel
3. 388+(0+(19*20))*1.1 = 806 ≈ 806 tons @ J1 = 80.6 tons jump fuel

100+89+80.6=269.6 tons total jump fuel
(101+180)-269.6=11.4 tons fuel available for power plant during voyage

500 - 388 = 112 / 1.1 = 101.8181 ≈ 101tons of external load capacity for small craft tonnage
(5*20) = 100 tons of small craft tonnage

1. 388+(16+(7*20))*1.1 = 559.6 ≈ 560 tons @ J1 = 56 tons jump fuel
2. 388+(0+(5*20))*1.1 = 498 ≈ 498 tons @ J2 = 99.6 tons jump fuel
3. 388+(0+(0*20))*1.1 = 388 ≈ 388 tons @ J2 = 77.6 tons jump fuel

56+99.6+77.6=233.2 tons total jump fuel
(101+156)-233.2=23.8 tons fuel available for power plant during voyage

---

For those triple jump computations, the important thing to remember is that the fuel consumption for the first 2 jumps needs to be as close as possible (with a bias to being slightly over if possible) the amount of jump fuel used during the jumps prior to the final jump.

So in the J1+1+1 calculation, the 100 tons of the first jump and the 89 tons for the second jump (combined) need to be higher than the 180 tons of collapsible fuel capacity. That way, all of the collapsible fuel is consumed during the first two jumps, opening up space in the internal hangar bay for Boxes and the Escort Fighter to be moved from exterior docking points into the internal hangar bay, reducing the combined (external) displacement of the starship plus external load(s) and reducing the amount of fuel needed to jump. It's this "transformation of the hull size" between each jump that makes the triple jump possible.

In the J1+2+2 calculation, there's an upper limit to how quickly jump fuel can be consumed (without being wasteful about it). So in order to "load balance" the fuel consumption with the "mobilization" of displacement from the interior to the exterior of the starship, you wind up with a consumption of 56 tons in the first jump and 99.6 tons in the second which is only 0.4 tons under the 156 ton collapsible fuel tank capacity needed to fuel those two jumps (and which equate to the movement of the Escort Fighter and 7x Boxes from the interior to the exterior). Fortunately, this "under consumption falls within the margin of error" for power plant fuel consumption rather easily. The final jump in the sequence can be done purely on normal internal fuel tankage in a "clean configuration" with no external loading.



For shorter 1J2 voyages ... 4 tons of fuel reserve can be added to the hangar bay cell with the Escort Fighter, to pad out the power plant endurance reserve. 5x Boxes get moved to dock with the exterior of the starship, creating a 498 ton combined tonnage for drive performance purposes. The hangar bay space those 5x Boxes had been occupying can be filled with 100 tons of cargo to be carried internally (at full price) during the voyage, increasing the total cargo allowance to 120 tons non-sensitive and 20 tons environmentally sensitive transport capacity, which will often times tend to be adequate for a variety of point to point runs. Another advantage of this particular arrangement is that ALL of the transport capacity is "owned" by the operator, no need to rely on third parties chartering external load capacity in order to fill the manifest.

For 1J1 voyages, there's going to be A LOT of external load capacity available for charter (380 to 540 tons of it, depending on circumstances). Note that this is plenty of external load capacity for an active and crewed ship of the class to externally tow an inactive and uncrewed ship of the class @ J1 and still have some external load capacity left over (1000-388=612/1.1=556.3636 ≈ 556-338 = 218 tons of external load capacity for small craft tonnage remaining ≈ 10x 20 ton Boxes + 1x 16 ton Escort Fighter). This means that starships of the class can be "delivered" to clients in other star systems for commissioning, rather than forcing clients to travel to the shipyard to take delivery off the production line. This capability also makes it easier for type B starports to have their shipyard construct all of the small craft (Escort Fighter, Boxes, Pods) for use with the starship class, while the type A starports monopolize construction of the starship proper.



So things got a little bit scary there, briefly ... but I'm glad I found my miscalculation and was able to compute my way to a solution for the 388 ton hull with 8x Boxes plus Escort Fighter design.



Now to get on with making a METRIC {FNORD}TON of edits to the text file storing all of the info for this monstrosity so that I can start assembling deck plans once I've gotten the spreadsheet "frozen" at the naval architect's office.

Gluttony ... meet punishment.



Starship design ... prepare to meet thy maker.

 

[Grav_Moped]

Which makes for a really interesting contrast between the two paradigms.
Depending on what is more "valuable" to you (cost, displacement, fuel load, revenue tonnage fraction, drive performance with external loads, etc.) the choice between the two options can vary in terms of optimum choices to balance competing priorities ... which is essentially the foundation of the engineering mindset, finding the best balance to optimize for competing priorities.

Yes, but it's dispuatable that both exist in the same setting.

 

[kilemall]

Yes, but it's dispuatable that both exist in the same setting.

Huh?

Makes sense to me that the paradigms exist to service different needs.

For instance, there is a range of diesel engines that served as standard power in tugboats, smaller boats etc and some locomotives and have been in production for decades, parts still available.

Then there are warships, huge container ships, cruise liners that have large engines and possibly specialized high power needs, economical cruising, or just size that cannot be served by any bank of standard motors.

What I have an objection to is mixing them in the same ship, both in terms of engineering standards and game tradeoffs. But 10% vs 30% hangar bay costs seems to be a small piffle and entirely reasonable, especially if it’s not a carrier.

 

[Spinward Flow]

Huh?

Makes sense to me that the paradigms exist to service different needs.

I agree.

What I have an objection to is mixing them in the same ship, both in terms of engineering standards and game tradeoffs.

Again, I agree.
Trying to mix 'n' match standard and custom drives in the same craft is just asking for trouble. First and foremost, cherry picking between the two paradigms in order to "blend" them together just feels ... intellectually dishonest, to me.
Use one or the other in the design of a craft, not both.

But 10% vs 30% hangar bay costs seems to be a small piffle and entirely reasonable, especially if it’s not a carrier.

Well, that little "110% every time" decision has had some knock on effects that I wasn't anticipating.
The big one is that I think it just rendered 4x 20 ton Boxes = 1x 80 ton Pods effectively useless. The problem is the "need 2G minimum performance" out of a 16 ton Escort Fighter in order to make the Pods effective/efficient/purposeful.

I hit this particular snag when doing the recompute of performance profiles.
This one is for the Escort Fighter.

Maneuver-6, Agility-6 @ up to 16 tons total (+0 tons external)
Maneuver-6, Agility-5 @ up to 20 tons total (+4/1.1=+3 tons external)
Maneuver-6, Agility-4 @ up to 25 tons total (+9/1.1=+8 tons external)
Maneuver-6, Agility-3 @ up to 33 tons total (+17/1.1=+15 tons external)
Maneuver-5, Agility-2 @ up to 40 tons total (+24/1.1=+21 tons external)
Maneuver-4, Agility-2 @ up to 50 tons total (+34/1.1=+30 tons external)
Maneuver-3. Agility-1 @ up to 66 tons total (+50/1.1=+45 tons external)
Maneuver-2, Agility-1 @ up to 100 tons total (+84/1.1=+76 tons external)
Maneuver-1, Agility-0 @ up to 200 tons total (+184/1.1=+167 tons external)

Oops.
The 80 ton Pod doesn't "fit" anymore under the 2G performance cap limit.

Which honestly, is probably for the better.
When the basic building block was multiples of 12 tons, having Pods that are 6-8x 12 tons made plenty of sense.
But when the basic building block is 20 tons, multiples of 2-3x 20 tons stop being a good idea as a step change. Just use 2-3x Boxes instead.

The 20 ton Box is "good enough" the proliferate on its own as a standardized container.
Need more space? Just add more Boxes to the pile.

 

[Grav_Moped]

Huh?

Makes sense to me that the paradigms exist to service different needs.

For instance, there is a range of diesel engines that served as standard power in tugboats, smaller boats etc and some locomotives and have been in production for decades, parts still available.

Then there are warships, huge container ships, cruise liners that have large engines and possibly specialized high power needs, economical cruising, or just size that cannot be served by any bank of standard motors.

What I have an objection to is mixing them in the same ship, both in terms of engineering standards and game tradeoffs. But 10% vs 30% hangar bay costs seems to be a small piffle and entirely reasonable, especially if it’s not a carrier.

I'm thinking the downport infrastructure requirements for HEPLAR or '77 Torchships are significantly different from '79-and-up grav drives. The latter might fall on your downport or city due to a systems failure, or might open fire so you have to watch for that. The former are doing takeoffs and landings using energy weapons!

 

[kilemall]

I'm thinking the downport infrastructure requirements for HEPLAR or '77 Torchships are significantly different from '79-and-up grav drives. The latter might fall on your downport or city due to a systems failure, or might open fire so you have to watch for that. The former are doing takeoffs and landings using energy weapons!

I never took the HG first edition engine as weapon seriously, for range if nothing else.

It does paint the picture of downports as out in the boonies, radiation and armor hardened.

 

[Spinward Flow]

I'm thinking the downport infrastructure requirements for HEPLAR or '77 Torchships are significantly different from '79-and-up grav drives.

That's taking things to a level of granularity beyond what I (personally) would consider to be "useful" (per se).
The way I see it, HEPlaR vs Thruster Plate M-Drive stuff is (in CT at least) not a case of "either/or" for Maneuver Drives (LBB5.80 and LBB2.81) ... instead it's a case of "both" since you will probably NEED to have both for a "go anywhere" maneuver drive that (for reasons of gamer bookkeeping simplicity) run on power plant EPs full time. That way, the maneuver drive's "output acceleration" remains a consistent value, regardless of context or circumstances (greatly simplifying gameplay).

I know that later editions of the game decided to split those two maneuver drive components apart to achieve that higher level of granularity in detail ... but from a CT design context, it's something of an irrelevant distinction. The maneuver drive code rating describes WHAT happens (#Gs of acceleration produced) without getting down into the technological weeds of HOW the engineering works to make that performance occur.

Maneuver drives are "space magic" the same way that fusion power plants (with no waste heat rejection features) and jump drives are also "space magic" technologies.

The latter might fall on your downport or city due to a systems failure, or might open fire so you have to watch for that. The former are doing takeoffs and landings using energy weapons!

Around "civilian" infrastructure, grav drives are definitely going to be the "safer/less destructive" option, since they're very nearly "pure electric reactionless propulsion" that is "safer" to be around (insert cell phone radiation conspiracy theories here).

Heh. I wonder if there are "lead foil hat" nut jobs out there who rant and rave about the "dangers of gravitics" the same way that the "tin foil hat" brigade rants and raves about the "dangers of electromagnetic signals" who are drowning in conspiracy theories.
There probably are.

As for HEPlaR being an "energy weapon" ... it's an energy weapon in the same way that a Mining Laser is an energy weapon (only at SHORTer than typical weapon ranges!). However, HEPlaR isn't "tuned" for use as a direct fire weapon of mass destruction. It CAN be in some specific edge case circumstances (if done deliberately), but that's going to be the exception rather than the norm.

Fusion Rocket reaction drives, though ... those tend to have a higher specific impulse and a "more destructive downstream" effect due to the higher (fusion) energies involved in the reactions producing the thrust.

 

[mike wightman]

Using the fusion drive as a weapon is at short range and the key word is may - you don't have to weaponise the drive. I assume some sort of magnetic or gravitic focusing of the drive exhaust.

 

[Spinward Flow]

I assume some sort of magnetic or gravitic focusing of the drive exhaust.

For efficiency and control, if nothing else.

 

[mike wightman]

Yup, with weaponising a military only option (or a morally challenged engineer who know how to add the weaponisation effect to a civilian drive)

 

[whartung]

Living with HEPlaR from day to day need not be that disastrous.

The TNE paradigm is contra-grav "lifters". The CG makes the ship almost buoyant, but no thrust, and with that the ship can use lower impact thrusters for the take off and landing. Neither TNE nor FF&S document those alternate thrusters in detail. They provide for such things (you could put jet motors on a ship for the last mile, for excample), but none of the stock designs are provided such. It's just kind of wrapped into the whole kit. "Add CG lifters, and you can take off and land without incinerating everything nearby." The base premise is that all ships have some kind of implicit low power thruster for fine control, and those can be used for take off and landing with the CG.

Its hard enough to keep the hot drives from igniting brush grasses on far off planets as is, with out adding nuclear fire to the equation.

 

[mike wightman]

Lifters are now a canonical part of ship in MgT.

 

[Grav_Moped]

Living with HEPlaR from day to day need not be that disastrous.

The TNE paradigm is contra-grav "lifters". The CG makes the ship almost buoyant, but no thrust, and with that the ship can use lower impact thrusters for the take off and landing. Neither TNE nor FF&S document those alternate thrusters in detail. They provide for such things (you could put jet motors on a ship for the last mile, for excample), but none of the stock designs are provided such. It's just kind of wrapped into the whole kit. "Add CG lifters, and you can take off and land without incinerating everything nearby." The base premise is that all ships have some kind of implicit low power thruster for fine control, and those can be used for take off and landing with the CG.

Its hard enough to keep the hot drives from igniting brush grasses on far off planets as is, with out adding nuclear fire to the equation.

Lifters are now a canonical part of ship in MgT.

And the softening of SF continues.... LOL

 

[Spinward Flow]

And the softening of SF continues.... LOL

Gamers: "It's bad enough that you want us to roll dice ... but now you want us to do MATH TOO?"
Referee: "So what did you roll?"
Gamers: "Uh ... who wants to know?"

 

[Spinward Flow]

For a long time now, I've been wanting to (somehow!) create a Laboratory Box that could be used as a building block for an astronomical interferometer telescope to do astronomy research with. Once you have the "basic building block" designed, just put that basic building block into volume production and "build a lot of them" for use in an orbital array to support academic research. Basically, something that a world(-class) university would sign onto to attract talent and specialists in the field, enhancing the university's reputation and prestige.

Remember how I did up a 12 ton Laboratory Box as an astromical observatory using THIS as inspiration ...

... that resulted in this for deck plans?

Well.
Here's the 20 ton Laboratory Box version of the same idea.
I think the idea turned out better in the 20 ton form factor.

For reference, the 12 ton Laboratory version had hexagonal mirrors just under 5.1m² mirror area each.
There were 3x2=6 mirrors for a total light gathering area of ~30.5² (roughly).

The 20 ton Laboratory version has hexagonal mirrors just over 6.4m² mirror area each.
There are 4x2=8 mirrors for a total light gathering area of ~51.5² (roughly), so a pretty decent scale up from the 20 ton form factor.

Best part is, you can review the raw data captured by the Laboratory Box (observatory) from the comfort of your stateroom in a Stateroom Box.

 

[Spinward Flow]

Things are starting to look intentional now.

20 ton Environment Box

20 ton Cargo Box

And with those complete, I can start building the aft hangar bay deck plan ... which I'm going to need to build first before wrapping the (updated) drive bays loaded with E/E/E drives in them. Think I'll do something different with the maneuver drive(s) this time, so the entire "drive stack" is just a single long column with the HEPlaR maneuver drive elements on the end. That way, I don't wind up with that weird "L kick" to outboard feature again. Ought to make it easier to just pull the (shorter) aft bulkhead and just slide the entire drive assembly out for annual overhaul inspections and maintenance.

Because the aft hangar bay is going to wind up being longer this time (because the 20 ton Boxes are longer) the overall silhouette may start looking "more superhypersonic-ish" in terms of length to width ratio with a "longer spine/tail" at the aft end of things. I'll have to see how it all shakes out once Deck Components Assembly begins.

At the very least, because the (new) 16 ton Escort Fighter deck plan is shorter than the previous iteration (which looked like a syringe, now it looks more like a slice of a peach to fit into the form factor of the 20 ton Box for maximum commonality of dimensions) ... the forward hangar bay on the upper deck for the Escort Fighter shouldn't need to be as long or extend as far forward.

I'm also thinking that rather than using an angled pressure door forward to enable horizontal (relative to the decks) launches and recoveries, that the new "cellular" design for the hangar bay spaces ought to have dorsal clamshell doors for vertical launches and recoveries, in addition to the aft door of the aft hangar bay being designed for use as a ramp assist for the loading and unloading of Boxes from the aft hangar in a roll on/roll off kind of way. The advantage of having dorsal doors as well as the aft door is that because the Escort Fighter now fits EXACTLY into the same form factor space as the 20 ton Boxes do, the Escort Fighter can descend through the opened dorsal doors to dock with Boxes and lift them out of the aft hangar bay "sky crane" style on planetary surfaces under gravity. This can solve some logistics and marshaling issues in locations where there may be inadequate ground services support (such as at type E or X starports, or when making deliveries to locations AWAY FROM starports/spaceports, for reasons various and sundry).



On another note, I was once again doing another "red team" analysis of alternatives along the lines of moving to a larger starship hull displacement rather than sticking with the 388 ton option ... when I noticed an accidental symmetry in the calculations that I hadn't spotted before.

The 388 ton option has a 200 ton hangar bay space (MCr0.4) which can host 200/1.1=181.8181≈181.8 tons of sub-craft/cargo, using the "110% tonnage for everything" paradigm rule that isn't strictly in compliance with LBB5.80, but has better compatibility with later editions of Traveller after CT. That 181.8 tons of craft capacity then gets used for 9x20 ton Box berths plus a 180 ton capacity Collapsible Fuel Tank(s) (1.8 tons required when empty) that can fill up the hangar with additional fuel reserves that can enable double (and even triple! ) jumping.

Those 9x 20 ton Box berths are occupied by the Escort Fighter plus 8x Boxes.
And it was then that I remembered the (new) drive performance profile of the Escort Fighter and its upper limit for being able to sustain 1G/Agility=0 maneuvering power:

Maneuver-1, Agility-0 @ up to 200 tons total (+184/1.1=+167 tons external)

What this means is that if the starship and the Escort Fighter need to separate for wilderness refueling reasons (for example), the starship can "dive into atmosphere" on an orbital skimming run or to set down on liquid water to refuel ... and the starship's entire hangar bay capacity can be empty (so as to load up the collapsible fuel tank). Meanwhile, the Escort Fighter can remain in orbit, docked to the 8x 20 Boxes (to keep them from drifting off) in a High Guard overwatch position, with 1G of maneuvering power while needing to stay outside of aerobraking distance to the world.

Then, once the wilderness refueling "scoop" action is complete, the starship and fighter can rendezvous in orbit and the Escort Fighter can maneuver to transfer the docking of the Boxes to the exterior of the starship in preparation for maneuvering to somewhere else.

When I saw that little bit of synergy ... that the Escort Fighter can maneuver @ 1G/Agility=0 with up to 8x 20 ton Boxes docked to it, I knew then that continuing to search for other starship hull sizes that could accommodate more Boxes (9+ and add the fighter on top) would be a mistake, since it would create logistics marshaling issues elsewhere that could become a weak point in operations.



So I *think* I'm getting close to wringing out all of the potential "oopsies!" that might have resulted if I'd chosen a different displacement number for the starship hull. Turns out that 388 tons (as oddball as that number sounds) is winding up being something of a "sweet spot" that's not too big and not too small at the same time. I'm seeing MULTIPLE factors converging on 388 tons being just about the ONLY starship tonnage number that works "optimally" along multiple parameters of operational importance, so once again the design winds up "balancing on the head of a pin" at a number that is NOT divisible by 100.

Funny that.

 

[Spinward Flow]

Things are starting to look intentional now.

20 ton Environment Box
20 ton Cargo Box

Decided to make a slight tweak update to the details of the Environment and Cargo Boxes.
I added a hatch to the pressure doors on the ends of the Boxes.

However, in order to do that, I needed to make the pressure doors asymmetrical.
That way, I could place the manual hatch on the center axis in ONE of the pressure doors (not both). What you wind up with is a big door on one side, with the hatch in it ... and a smaller door with no hatch in it.

Here's how that changes things.

20 ton Environment Box

20 ton Cargo Box

The difference is a bit subtle, but you can see the "gap" between the pressure doors (where they open) has been offset to port and starboard around the manual hatch that is now integrated into the "longer" of the 2 pressure doors on each end of the Boxes.



The reason for making this deck plan design choice adjustment is that unlike with the previous 12 ton Boxes, the 20 ton Boxes are not and cannot be square ... they have to be rectangles. That in turn means that they need to be loaded into the hangar bay longitudinally, they can't be rotated 90º to point the pressure doors off to port/starboard anymore.

A consequence of that particular deck plan context change then means that if other Boxes (such as Stateroom or Laboratory, for example) are to have any kind of "in flight access" to the contents of the Environment and/or Cargo Boxes, then there needs to be a personnel access point added to the center of the longitudinal axis that can meet up/dock with the central access corridor spaces of the Stateroom and Laboratory Boxes.

So let's say you decide to put a vehicle berth into a Cargo Box.
If you want to be able to "get at" that vehicle without needing to go outside from another Box in the daisy chain, you need to "dock" the two Boxes together using the extendable airlock on the ends of the central access corridor from another Box. That then allows you to move from Box to Box without going outside in order to access the vehicle berth inside the Cargo Box. If it's a grav vehicle (and it probably should be, all things considered), then the berthing arrangement can modify the dorsal bulkhead to include another pressure door up top for the vehicle to lift up out of and fly away.



Totally a Quality of Life change to the deck plan "interior design aesthetic" which has NO IMPACT of any kind on the naval architect's spreadsheet of design specs ... but a necessary change, I'm thinking, to make living with and working around these Boxes easier, especially if you need to modify them for specific purposes, such as the addition of vehicle berths, etc.



The update will make more sense when I start building up the aft hangar bay for the starship and can start putting the various 20 ton Boxes into their "daisy chain" locations within that hangar space.