Pondering starship evolution

[Grav_Moped]

I'm looking at this and seeing slide-out cargo space, as with an RV's bedrooms. Not allowed by RAW (for tolerably obvious reasons) but this is a decent work-around for it.

 

[Spinward Flow]

More fun with deck plans!



Behold ... the 96 ton Cargo Pod (2 decks tall)!

With the basic outline of a generic Pod shape available, it was time to start working on the double jump configurations.

J2+3

---

J2+2

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J1+1

---

I think that completes all of the images I'm going to need to finalize the visuals needed for this class redesign.



Still really impressed by how well everything integrates together ... both on the naval architect office spreadsheet AND in deck plans (although the former was way easier to accomplish than the latter! ) ... although I kept waffling on the spreadsheet details for far too long before freezing the design specs.

Also glad I found that 327*1.1=359.7 round up to 360=30x12 ton Boxes "symmetry" for having these ships "tow each other" (@ J1/1G with one ship "live" and the other one "dead load") for all kinds of salvage and reocovery options.

Another irony of the design is that I was always assuming (at least at the start) that a J3 capability with such a small amount of revenue tonnage available to it (5 high passengers, 12 tons cargo plus 12 tons environmentally controlled cargo) would be horrendously "overbuilt" relative to the demand for transport services. But then once I got to the point of calculating the revenue tonnage available with external loading in a J1 microjumper configuration for being able to move passengers and cargo to Far Companion Stars within the same parsec ... oh me oh my! ... all of that "overbuilt" capacity suddenly turned into Nothin' But Gravy when (externally) loading up to the max and HAULING incredible amounts of passengers and goods.

Meager profits on the margins @ J3 ... all the way out to megacredits per jump ticket revenues potential when operated as a microjumper or as a J1 interstellar barge. Granted, speculative goods CAN potentially exceed those kinds of profit levels when the trade winds are favorable, but that's hardly a "sure thing" like simple passenger and freight tickets can be (especially when chartered).

Even better yet, a 1000 ton J1/1G Type-A wouldn't be "better" at doing the same job (except maybe on the margins), would probably cost more to construct and operate (if streamlined) ... and wouldn't have the same amount of built in flexibility (J1-3 depending on external loading vs J1 all the time, every time). So a bigger ship winds up costing more to get "less" ... and as a 1000 ton starship would essentially be "chained" to the only trade route options capable of generating enough demand for services to break even on overhead costs (greater risk, less opportunity for rewards).

Being able to "scrimp and save" in order to be able to make ends meet on the balance sheet with very limited demand for high passenger and cargo transport tickets means that it's possible to "Economically Go Where No One Else Has Profited Before" (or words to that effect ) and avoid flirting with bankruptcy for your troubles.



One of the legacies of LBB S3 and S10, along with all of the sector maps prior to the availability of Travellermaps, Travellerwiki and Traveller Worlds to provide system info (planets, planetoid belts, gas giants, etc.) is that we tend to think of all the points on the hex maps as being SINGULAR destinations. There's ONE mainworld ... and nothing else in a star system ... just ONE place, which is basically the starport and almost anywhere else is just conveniently ignored (except when it can't be).

As Referees and as Players, we need to start thinking more broadly.
Each hex with a star system in it can have 1+ stars ... and probably has 0+ worlds in orbit around those stars ... meaning there are a LOT more placed to go and see (and deliver passengers and goods to) than just the main starport on the mainworld that gets its UWP listed for the parsec.

Increase the number of places you can go to and you increase the number of possible REASONS for wanting to go somewhere other than "just the starport" in any given system.



And if you want a "go anywhere, do anything" starship that just needs a brave crew and a few stars to navigate by, have you heard about what the SIE corporation has been working on at their headquarters in the Grote/Glisten/Spinward Marches system ... { volume trails off }

 

[Spinward Flow]

a 1000 ton J1/1G Type-A wouldn't be "better" at doing the same job (except maybe on the margins), would probably cost more to construct and operate (if streamlined)

I should probably explain why I made that assertion.
It basically comes down to the cost of hull metal (under LBB5.80 construction rules).

• 1000 tons of hull (starship) = MCr100
• Configuration: 1 = +MCr20
• Configuration: 2 = +MCr10
• Configuration: 6 = -MCr20
• Fuel Scoops = MCr1
• 16 tons of hull (fighter) = MCr1.6
• Configuration: 1 = +MCr0.32

So for a streamlined hull, you've got a construction cost of MCr82.92 to MCr122.92 when including a 16 ton Escort Fighter for defense, depending on choice of configuration (obviously "flattened spheroid" is cheaper and "needle/wedge" is more expensive). Point being, that's the baseline cost for metallic hull metal.

Now compare that price to what the SIE Clipper design does with modular containerized shipping in a fully loaded J1 context.

• 327 tons of hull (starship) = MCr32.7
• Configuration: 1 = +MCr6.54
• 16 tons of hull (fighter) = MCr1.6
• Configuration: 1 = +MCr0.32
• 96 tons of hull (boxes) = MCr9.6
• Configuration: 4 = -MCr3.84
• 6x 96 tons of hull (pods) = MCr57.6
• Configuration: 4 = -MCr23.04

32.7+6.54+1.6+0.32+9.6-3.84+57.6-23.04 = MCr81.48

Advantage ... modular containerized shipping business model and practices.

But that's just the start of the divergence.



The 1000 ton J1 transport starship is going to have an ENORMOUS revenue tonnage fraction (passenger and cargo capacity) ... which will then need to be FILLED CONSISTENTLY in order for ships of the class to be profitable (both for operators and for subsidizing governments). This is very much an "all eggs in one basket" type of approach to interstellar trade. Now, if you've got that kind of "demand signal" for interstellar transport services ... by all means, more power to you ... but that kind of circumstance (on the regular) is going to require trade routes between worlds with plentiful populations (Non-industrial and below need not apply) in order to "load balance" between supply (of tickets) and demand (for those tickets) in order to keep shipping manifests full and profits flowing to investors.

Point being that you need "big markets" in order to support "big ships" to service the routes between those markets.
And the moral of THAT story is that the "big boys" (see: megacorps) are going to have a hammer lock on cornering those big markets, if for no other reason than because big markets with high volumes of trade generate the most profits.



Compare and contrast that with the 327 ton J3 SIE Clipper concept that I've been developing.

Due to the external load capabilities, the ship can be OPTIONALLY either "big OR small" depending on the "economic terrain" of where you want to go to conduct business. You can be a "bulk transport" over J1 (or J1+1) distances or you can be a "small transport" over J3 (or J2+3) distances when you need to be. The modular containerization system has the added benefit of bringing third parties into the mix, who would own their own 12 ton Boxes and 96 ton Pods and simply need to have those assets transported. In other words, the starship operator doesn't need to "do all the work" of scaring up business to fill out their shipping manifest ... a portion of that task can be "outsourced" to third parties who act as intermediaries selling Transport as a Service (TaaS). Those third parties then just simply need to charter a portion of an SIE Clipper's external load capacity (ala barge+tug) to get THEIR Box or Pod wherever the SIE Clipper is going next.

The advantage is that by "distributing" the capital invest cost for interstellar trade capacity among more players in the market, you both increase competition between those third party companies while also tapping into a larger pool of capital than any single investor needs to commit to the entire venture. You wind up with a "pool" of investments from a variety of sources and interests, all seeking the services that the starship operator can provide. But most importantly, it means that it becomes possible for "merchants" to conduct interstellar trade WITHOUT needing to OWN (and crew) a starship themselves. You essentially "grow the pie" and invite more players into the market, increasing the "shares" of everyone involved, promoting interstellar trade and exchanges ... which grows the soft power of worlds and grows markets (and profit margins).



For me, the primary difference between the two business model approaches is the difference between One Size Fits Some compared to a Many Sizes Fits Most design philosophy in which it becomes both possible and profitable to "tailor" a starship's revenue tonnage capacity to "meet the moment" in as wide a variety of different market sizes and conditions as possible (small to large), rather than being "locked in" to only being able to load balance and take advantage of a select chosen few large(r) markets with the highest trade volumes.

Being able to "go big but near" all the way through "go small but far" means that your starship can ADAPT to changing locations and market circumstances (not all UWPs are the same let alone equal ). Additionally, by making it possible to "get a piece of the action" at a lower capital investment stake than the price and cost of constructing an operating an entire starship and crew the barriers to entry get lowered and a sort of "wisdom of crowds" starts coming into play, creating economic conditions in which a kind of crowdfunding of interstellar trade capacity becomes both reasonable and profitable for multiple parties, not just one.

So instead of having a "top down megacorp" mindset and approach to interstellar trade, you get more of a "bottom up/middle out" competition among the small time economic interests, who can then work to grow by either investing in more "shares" (Boxes and Pods) and/or by growing the "pie" (volume of trade overall increases) in which everyone benefits ... including the subsidizing government that made the whole thing possible in the first place through wise and prescient foresight and industrial policy decisions to invest in getting the virtuous cycle started.

"You see, there are millions upon millions of worlds in the universe. Each one filled with too much of one thing and not enough of another. And the Great Continuum flows through them all like a mighty river, from have to want and back again. And if we navigate the continuum with skill and grace, our ship will be filled with everything our hearts desire!"
"Right now I'd settle for a stabilizer and a captain's desk."
"The river will provide."
"Hngh. If it doesn't sink us first."

 

[Spinward Flow]

As I'm sure people have already seen, I've put "legacy disclaimers" on my old starship designs posted in The Fleet of this broad business type and model, in case there are any forum readers who come along in later years and are looking at the archived back catalog of starship designs and wonder if "the old ones" are any good for use in campaigns. So the following notice in all of those threads is mainly a matter of "garbage collection" for old ideas in a way that doesn't delete them out of existence (and deprive future generations of forum readers of access to ideas and debates).

This starship design is being retconned out of existence and "de-canonized" (for whatever that's worth) by the author (me), in favor of a superior design that I will be posting ... Soon™.

I'm going to wait for a bit before posting the results of my research done in THIS Pondering Starship Evolution thread here over in The Fleet forum to replace all of those starship designs I've been doing for the past couple of years.

I would like to give The Fleet forum a chance to "breathe" before I unleash the 20 posts in a row in one thread needed to adequately convey everything that I've been working on in THIS thread to "perfect" the design of the 327 ton J3/3G Clipper with Escort Fighter and Boxes.

The culmination is coming.
It won't be long now ...

 

[Spinward Flow]

Hmmmm.
Have I missed a trick here?

The 327 ton J3/3G Clipper is a "solid" bit of design, even if I do say so myself.
However ...

There is an opportunity for a 476 ton J2/2G Long Trader built around the exact same E/E/E drives design balance point that would be capable of carrying a larger internal revenue tonnage fraction.

Additionally, when double jumping, a 476 ton starship could be configured to achieve J2+2 or J1+2 while carrying a "larger useful load" of revenue generating tonnage. The tradeoff would be a loss of the option for either J3 or J2+3 in exchange for J2 or J2+2, which isn't that much of a mobility loss in terms of maximum capabilities.



This is definitely going to be worthy of additional research after I get the 327 ton Clipper posted.



Oh, and why 476 tons specifically?
Well ...

1000 / 2.1 = 476.19047619047619

476 * 1.1 = 523.6 ≈ 524 tons
476 + 524 = 1000 tons ... so 1 active ship of the class can "tow" a docked inactive ship of the same class externally @ J1/1G if necessary

1000 - 476 = 524 / 12 = 43.66667
(43*12) + 476 = 992 tons @ J1/1G using E/E/E drives
(2*12) + 476 = 500 tons @ J2 using E/E/E drives



Some interesting confluences might result from investigating this follow up possibility.

 

[Spinward Flow]

Always. Always. ALWAYS ... question your convictions ... even when you're SURE you've already found The Right Answer.

As longtime readers of this thread will already know, one of the reasons that I settled upon the "12 ton box" form factor for modules is that I just couldn't figure out a way to make a "10 ton box" work without being needlessly wasteful. The "12 ton box" form factor made a really NICE looking 7.5x7.5x3m square box (168.75m³/14≈12 tons) which had the benefit of being able to 90º rotate and "still fit just fine" to permit all kinds of "jhenga stacking" in 3D such that you only needed 1 horizontal corridor and a vertical lift through the center for access through a set of linked up boxes (N/S below, E/W above in a 2x2x2 stack of 8 boxes).

That "12 ton box" form factor then became the fundamental building block for a modularized "container transport" standard which could be built up into use for jump/maneuver tug starships. The 5x5 deck squares arrangement was COMPACT with a minimum of wasted space, while also representing the absolute minimum size that I could craft a single occupancy stateroom into (2.5x2 deck squares, to be exact), not including (shared) access corridor space. The "odd number of staterooms plus one" helped create the necessary "four corners of symmetry" needed by the deck plans, yielding a "nicely balanced" look to the final results.

Observe.

​

Everything else got built upwards from that "lowest common denominator constraint" of needing to build everything in multiples of 12 tons (and preferably in even numbered multiples of 12 to keep things "balanced" in 3D).

The "odd number of staterooms plus one" helped create the necessary "four corners of symmetry" needed by the deck plans

Hold on.
Wait a minute.

If 3 starship staterooms = 12 tons ... and 3+1=4 (an even number) ... and a minimum deck plan of 2.5x2 compartment spaces can fit 4x into a 5x5 square box with a 5x1 access corridor shared between them ...
(2.5*2)=5
5*4=20
20/25 = 80% volume used by compartment living spaces out of 5x5 deck square box form factor displacing 12 tons

Then 5 starship staterooms = 20 tons ... and 5+1=6 (another even number) ... a minimum stateroom deck plan of 2.5x2.25 compartment spaces ought to be able to fit 6x into a 7.5x5.5 rectangle box with a 7.5x1 access corridor shared between them ...
(2.5*2.25)=5.625
5.625*6=33.75
7.5*5.5=41.25
33.75/41.25 = 81.8181% volume used by compartment living spaces out of 7.5x5.5 deck square box form factor displacing 20 tons

So by switching from a 12 ton "square" deck plan to a 20 ton "rectangular" deck plan form factor, the amount of volume that needs to be spent on corridor access FALLS (slightly) as a fraction of usable volume? And the stateroom compartments get LARGER at the same time?

And what's this 7.5x5.5 deck squares stuff? Where did those numbers come from?
That's just ... weird.

Well ...

(7.5*1.5) * (5.5*1.5) * 3 = 278.4375m³
20 * 14 = 280m³
278.4375 / 280 = 99.44%

Here's what it looks like when you take that set of fundamental building blocks and assemble them together into a basic foundational structure to make deck plans with:

And here's what happens when you stack these 7.5x5.5 rectangles on top of each other into a 2x2x2 block of modules, with the top layer rotated 90º from the lower layer:

Not QUITE as compact as a 2x2x2 stack of squares (because you're stacking rectangles instead), but that "wasted space" around the edges is nowhere NEAR as bad as it could have been. It's also aggregating together as a bit more "dispersed structure-ish" than the purely square stack would when doing the same thing.

The big takeaway here though is that a 2x2x2=8 block of 12 ton (square) box modules adds up to 96 tons ... while a 2x2x2=8 block of 20 ton modules adds up to 160 tons ... which then has implications for making "pods" that are really just multiple blocks of modules stuck together.

12 * 8 = 96 tons = Hull Code: 0 displacement size (still)
20 * 4 = 80 tons = Hull Code: 0 displacement size (still)

So how everything "stacks" together (on the spreadsheet mathematically and in the "2D trying to be 3D" deck plans) undergoes a subtle but important shift by switching to a different form factor.

Obviously, a 20 ton (rectangular) "box" foundational unit would make a LOT of factors easier to deal with when it comes to things like major and minor cargo lots, which come in 10 ton and 5 ton multiple sizes.



This is exactly the kind of mental/conceptual breakthrough that I needed in order to legitimately question whether or not the 12 ton, 5x5 deck squares "box" container module was the optimal solution that I thought it was (and have been convinced of for some time now).

Now I'm left wondering if the 20 ton, 7.5x5.5 deck squares "rectangle" container module makes for a superior choice of fundamental building block ... with all kinds of knock on (conceptual) side effects that favors an extremely foundational shift in assumptions, starship construction and even economic possibilities.



Only one way to find out ...

 

[bookwyrm]

You know, if you do as good a job with the rectangle version as you did with the square version, I would consider them both to be viable for the ship mission they are best suited for. And if the ship is big enough, you could probably use both if the ship mission requires the different capacities/volumes.

 

[Spinward Flow]

You know, if you do as good a job

So ... no pressure ...

with the rectangle version as you did with the square version

I've been "testing" ideas in that direction this afternoon after posting #246 and ... both the results and the implications are coming back with answers that suggest the 327 ton J3/3G Clipper is ... potentially suboptimal ... in some important ways. The most problematic conclusion is that a 476 ton J2/2G Long Trader is "weighing in" as having in preliminary analysis (details highly likely to change):

• Model/2bis computer becomes Model/2fib computer
• Crew increased from 7 to 8, minimum crew skills for pilots upgraded to Pilot-2 so they are interchangeable for starship and small craft
• 1x 16 ton Escort Fighter
• 3x 20 ton, (rectangular) stateroom boxes with 5 single occupancy staterooms each
• 3x 20 ton, (rectangular) laboratory boxes with Environmental Control Type V-d capacity: up to 5 persons each (aquaculture, hydroponic wall gardens and carniculture)
• 1x 20 ton, (rectangular) environment box for environmentally sensitive cargoes
• 1x 20 ton, (rectangular) cargo box for non-perishable cargoes
• High passenger capacity increased from 5 to 7
• 1x Air/Raft berth
• 1x Speeder berth
• 1 ton Magazine (can store up to 20 reloads for missiles and sand canisters) as an ordnance reserve for the Escort Fighter
• 1 ton Internal Demountable Fuel Tank for emergency black start recovery in the event of loss of all fuel from main fuel tanks
• 5 ton Mail Vault as a default
• ~80 ton cargo hold with 80 ton capacity collapsible fuel tank integrated enabling J2+2 at the expense of cargo capacity

The opportunity that I wasn't expecting to find (but am glad that I did, in terms of concept) is the notion that the regenerative life support biome laboratories could be upgraded from Environmental Control Type V-c (used on the 327 ton J3/3G Clipper design) to being Environmental Control Type V-d in a 476 ton J2/2G Long Trader redesign.

327 tons = 5 high passengers + 12 tons environment tank + 12 tons cargo box @ J3/3G, capable of J2+3
476 tons = 7 high passengers + 20 tons environment tank + 20 tons cargo box + 80 tons cargo hold @ J2/2G, capable of J2+2



The difference in high passengers is almost bizarre.
I could either have ...

• 3 high passengers
• 7 crew (Medical-3 skilled medic)
• 2x 20 ton, (rectangular) stateroom boxes with 5 single occupancy staterooms each
• 1x 20 ton, (rectangular) laboratory boxes with Environmental Control Type V-c capacity: up to 10 persons each (aquaculture, hydroponic wall gardens and carniculture)
• = 60 tons of boxes for 3 high passengers

... or ...

• 7 high passengers
• 8 crew (Medical-4 skilled medic, 1 Ship's Troop for onboard security)
• 3x 20 ton, (rectangular) stateroom boxes with 5 single occupancy staterooms each
• 3x 20 ton, (rectangular) laboratory boxes with Environmental Control Type V-d capacity: up to 5 persons each (aquaculture, hydroponic wall gardens and carniculture)
• = 120 tons of boxes for 7 high passengers

Why the addition of (a single) "Ship's Troops" member of the crew?
Because the alternative would be to add another Steward to the service crew instead ... and Corporals (according to LBB4) are "cheaper" than Stewards, in terms of salaries.

• 327/1000 = 0.327 * 3 = 0.981 (round off) ≈ 1 service department position for a 327 ton starship ... +1 steward for 5 high passengers = steward/steward crew position with Environmental Control: Type V-c life support laboratories
• 476/1000 = 0.476 * 3 = 1.428 (round off) ≈ 1 service department positions for a 476 ton starship (with no ship's troops) ... +1 steward for 7 high passengers = purser + steward/steward crew positions (2 crew) with Environmental Control: Type V-c life support laboratories

• 476/1000 = 0.476 * 3 = 1.428 (round up) ≈ 2 service department positions for a 476 ton starship (with no ship's troops) ... +1 steward for 7 high passengers = purser + steward/steward crew positions (2 crew) with Environmental Control: Type V-d life support laboratories
• 476/1000 = 0.476 * 2 = 0.952 (round up) ≈ 1 service department positions for a 476 ton starship (with ship's troops) ... +1 steward for 7 high passengers = steward/steward crew position (1 crew) with Environmental Control: Type V-dlife support laboratories
  • 476/1000 = 0.476 * 3 = 1.428 (round off) ≈ 1 ship's troop position for a 476 ton starship (1 crew)

All things considered, going from 327 tons to 476 tons is an increase of +45.56575% in terms of exterior displacement with no external loading.
But internally the regenerative life support biomes upgrade from V-c up to V-d, requiring +1 to medical skill and the addition of a ship's troop(s) security staff member, yielding an even BETTER quality of life aboard for both crew and passengers(!) ... high passenger capacity increases by +2 and cargo transport capacity increases from 12+12=24 tons to 20+20+80=120 tons(!). Even better yet, the 476 ton ship would be able to J2+2 simply by reducing cargo capacity (to make room for a collapsible fuel tank) without needing to "move" anything outside the hull (unlike the 327 ton ship, that needs to "mobilize" boxes outside to achieve J2+3 performance).

To put it mildly, the sheer amount of difference in potential and flexibility gained is (... so far ...) simply eye watering.



One of the key deciding factors for me, as a "naval architect/starship designer" is the question of just HOW NECESSARY IS a range of J3 combined with J2+3 ... compared to the alternative of J2 combined with J2+2 capability?

The answer to that question basically comes down to resolving how critical is a distance of 3 parsecs or 5 parsecs going to be in getting around when it comes time to move speculative goods, compared to a "limitation" of only 2 parsecs or 4 parsecs?

In order to achieve an answer to THAT question, you need to be looking at THE MAP.



As you can see from looking at this portion of the Spinward Marches, there are a FEW edge cases where being able to J3 (or J2+3) can effectively "save a week" in jump between 2 places of interest, but honestly ... the need for that is actually kind of rare. Even making the "long haul" from Iderati/Five Sisters to Glisten/Glisten is a difference between 8 jumps (minimum) @ J2 versus 5 jumps (minimum) @ J3.

So is J3 "nice to have" when you need it?
It most definitely IS!

Do you "need it often enough" to make sacrificing your revenue tonnage to get it a "worthwhile tradeoff" in the grand scheme of things?
Quite possibly not ... especially if J2+1 and/or J2+2 is "good enough" to get you where you need to go.
So this turns into being a case of "don't let the perfect become an enemy of the good enough" when you run ALL of the computations and dive more deeply into the implications.



All of which is to say that I'm (once again) coming to realize that high jump+high maneuver power comes at a COST which can quickly push starship economics into the borderline/marginal/risky range. By contrast, relaxing demands on drive performance can drastically improve balance sheet opportunities in other ways that aren't necessarily going to be immediately recognizable (until you do the work and start running the numbers and modeling results).

Pondering starship evolution INDEED ...

 

[Spinward Flow]

Hmmmm.

LBB2.81 E/E/E drives that are Code: 1 @ 1000 tons displacement are TL=10.
Bioregenerative life support hydroponics are TL=9.
M-Drive reactionless thruster plates are TL=9.
Sandcasters get +1 code factor @ TL=10.
Makertech starts @ TL=10.






If I fall back from TL=10 to TL=9 ... what happens?



LBB2.81 D/D/D drives is as far as you can go with TL=9 and are Code: 1 @ 800 tons displacement.
Total drives displacement is 45 tons.

1000/2.1 = 476.1904761904762 ≈ 476 tons
800/2.1 = 380.952380952381 ≈ 380 tons

So the first thing is that the starship hull size drops from 476 tons down to 380 tons ... which just so happens to be EXACTLY the right size to dock a 20 ton box externally and not lose any drive performance.

380*1.1 = 418 tons
380+418 = 798 tons @ J1/1G

However, if I want to be able to externally tow 400 tons of generic big craft/starship ... at 110% of displacement cost accounting (because big craft) ... that means I'm going to need to design the J2+2/2G Long Trader using a 360 ton hull instead.

So a crewed and operational ship of the class could externally tow an uncrewed and inactive ship of the class via jump and maneuver, if necessary, covering circumstances of needing to "deliver" completed starships to customers in other/foreign star systems away from the shipyard production line.

Starship computer is going to be a model/2 (I'd prefer a fib if at all possible), which is TL=7.
Escort Fighter computer is a model/3, which is TL=9 ... so no "lower bound" tech problems there.

A 200 ton capacity fuel purification plant (the minimum size) will require 9 tons @ TL=9, instead of 8 tons @ TL=10, but that's probably an acceptable "downgrade" in the overall design spreadsheet accounting.

Fuel tankage @ 360 tons of hull would be 72 tons for 2 parsecs and 20 tons for power plant with a J2/2G performance output.





45+72+20+9+20+4+16 = 186 tons for "primary systems"
360-186 = 174 tons remaining for crew, passengers, cargo and various other sundry "Hangar Bay Stuffs™"

That basically computes out as 8x 20 ton box modules (160 tons) + 14 tons extra.





It CAN be done ... but the J2+2 via collapsible fuel tank starts taking "too much" of a bite out of the available revenue (specifically: cargo) tonnage. Although, at 360 tons of hull, there would still be room for 2x 20 ton boxes to be towed externally while retaining J2 capability (because 360+20+20=400 @ J2/2G on D/D/D drives). However, in order to J2+2, you would basically need to sacrifice "too much" of your cargo capacity, rendering the option of limited worth in the arbitrage of speculative goods.



As much as I would like to think that a "low tech" TL=9 D/D/D drives variation on the theme that I've been working on would be feasible, it's looking like the tradeoffs needed to make it work would probably be "too expensive" to really be feasible yet.



476 tons with E/E/E drives enabling J2+2 performance @ TL=10 it is, then.

 

[Spinward Flow]

switching from a 12 ton "square" deck plan to a 20 ton "rectangular" deck plan form factor

What happens to the regenerative biome life support laboratory deck plan?

12 ton 5x5 squares deck plan laboratory
Environmental Control: Type V-c for up to 6 people

This level relies more upon the gardens for providing food than the algae vats. It also incorporates small animals like chickens or fish (usually any edible herbivore up to about 10kg).

20 ton 7.5x5.5 squares deck plan laboratory
Environmental Control: Type V-d for up to 5 people

This level relies entirely upon gardens to provide both air and food. At this level larger animals can be incorporated into the environmental systems.

Lots of hydroponics (garden walls and deep water over aquaculture tanks) along with fruit bearing bushes/trees as well as adequate carniculture (aquaculture for fish and either live meat animals or "lab grown meat" machines). The amount of life support machinery (behind maintenance panel access points) is also increased to provide the necessary buffering and load balancing of the regenerative biome systems under the supervision of the Service department (Steward-1/Steward-1) and Medical department (Medical-4).

Incidentally, for anyone who enjoys "interior decorating" trivia ...

The 12 ton 5x5 Laboratory Box deck plan allocated only 4*(2x2)=16 deck squares out of 5x5=25 deck squares total to actual biome species habitat compartments.
16 / 25 = 64% of total deck area

The new 20 ton 7.5x5.5 Laboratory Box deck plan allocates only 4*(3.25x2.25)=29.25 deck squares out of 7.5x5.5=41.25 deck squares total to actual biome species habitat compartments.
29.25 / 41.25 = 70.9090% of total deck area



It took me a while to settle down onto a broad outline for how I wanted the interior details to be arranged in this redesign. Might still do a flip vertical and replace the text so as to do a better Feng Shui/Hindu compliant arrangement with the "water and blood" compartments on the port side, rather than the starboard as shown above.

One thing that I definitely DO like about this redesign is that each of the biome compartments are "big enough to breathe" in, rather than being cramped to the point of questioning whether or not the spaces allocated are adequate to do the job. Now I look at that 20 tons of laboratory space and think that ought to be enough to sustain 5 people at a Type V-d standard of regenerative biome life support. In practice, it makes every single occupancy stateroom require 8 tons (4 for the stateroom and 4 for the laboratory) and cost MCr1.3 each (MCr0.5 for the stateroom and MCr0.8 for the laboratory).



Fun thing is that Environmental Control: Type V-d is actually suboptimal for use on a starship that isn't subsidized, relative to the typical Cr2000 per 2 weeks per person life support overhead cost ... except in subsidized service due to the 50% revenue rake by the subsidizing goverment, while overhead and maintenance expenses remain unchanged for the operator.

This means that in subsidized service you need 4 tons of cargo tickets to generate the Cr2000 of revenue needed (after 50% subsidy revenue rake) to offset the Cr2000 per person per 2 weeks cost of life support. However in my own house rule homebrew regenerative life support biome for starships interpretation, Environmental Control: Type V-d requires +4 tons (of laboratory) per person be allocated, reducing revenue tonnage by effectively the amount of revenue that 4 tons of cargo ticket sales could generate for an operator. There are other overhead expenses that prevent the comparison from being truly 1:1 (due to crew salaries and annual overhead maintenance costs) ... but I consider the upgrade in the Quality of Life aboard ship (not to mention crew quality and loyalty) to be worth those added expenses.

It's one of those "at what price, envy?" kinds of deals, relative to whatever competition you and your crew might be facing with regard to demand for your tickets. Besides, the higher grade of life support just makes the class even more worthy of being used as a status symbol YACHT by the rich and (in)famous.



Might try seeing what happens with a "telescope observatory" type of laboratory box next in the 20 ton form factor.

 

[Spinward Flow]

switching from a 12 ton "square" deck plan to a 20 ton "rectangular" deck plan form factor

What happens to the staterooms deck plan?

12 ton 5x5 squares deck plan staterooms with either lounge/galley/laundromat or medical infirmary with autodoc
Note that the only difference is the addition/removal of the 2.5m long bunk loft bed over the seating area, shown using 2 views for clarity.

​

20 ton 7.5x5.5 squares deck plan staterooms with either lounge/galley/laundromat or sick bay with autodoc
Note that the only difference is the addition/removal of the 2.5m long bunk loft bed over the seating area, shown using 2 views for clarity.

​

Interesting things to note in the 20 ton revision:

• The extra 0.25 deck square of port/starboard width to compartments is doing an awful lot to "uncramp" the usage of space in each individual compartment. The amount of walk space available is markedly improved.
• Closet storage space has been consolidated into a single deeper floor to ceiling closet in each stateroom. This actually increases the amount of available storage volume (in m³) in each stateroom. 1.25m wide, 0.75m deep, 2.5m tall, 234 liters of closet volume. A vacc suit and rescue ball are typically stored in each stateroom closet (standard) for protection against depressurization.
• Because the skill level of the onboard medic needs to rise to meet the minimums needed for Environmental Control: Type V-d from 3 to 4, the medical infirmary is upgraded to a sick bay. Side note, the change in compartment size simple left enough room for the change in text to be able to fit without overlapping any other part of the iconography.

One of the side effects of switching from a 12 ton square form factor to a 20 ton rectangular form factor is that "chains of boxes" get longer.

• 4x 5 deck squares long = 20 deck squares + some incidental spacing = 21 deck squares in length of aft hangar bay
• 3x 7.5 deck squares long = 22.5 deck squares + some incidental spacing = 23.5 deck squares in length of aft hangar bay

The thing is, I can stack the 20 ton boxes vertically into an upper deck, but that will only work up to a certain point before it "unbalances" the outer hull line of the starship's silhouette (making it look goofy and stupid , rather than looking sleek and elegant in an intentional way ). This is starting to cause some ... issues ... with how I lay out the deck plans for the larger 476 ton hull size, because in that case the hull is going to be "mostly hangar bays" in the aft end.

Right now, I'm starting to think I'm going to have to resort to an arrangement of 2 boxes wide (port/starboard), 2 decks high (main deck, upper deck) and 3 boxes long (fore/aft) ... giving me a total of 12x 20 ton boxes ... which on the naval architect's spreadsheet adds up to a total of 240 tons of hangar bay space, before including the 16 tons of hangar bay space needed by the Escort Fighter. That's 256 tons (minimum) allocated to internal hangar volume in a starship class that only displaces 476 tons in a clean configuration, unencumbered by external loads.

However, doing that dramatically WIDENS the aft hull.
I'm looking at an aft hangar bay that needs 18-20 deck squares of width in the aft hull section for the 476 ton J2/2G Long Trader. Compare that with what I was doing in the 327 ton J3/3G Clipper where I was dealing with a with needing to account for only 13 deck squares of width in the aft section. That's going to make the deck plans look a LOT ... chunkier ... and aft end "heavy" than the previous "sleekly elegant" design did.

I honestly worry that the rebalancing into a "more than 2x larger aft hangar bay" is going to do some UGLY UGLY "hackish" things to the silhouette and proportions I achieved with the 327 ton deck plans.

It might not turn out that way, once I actually start honing in on the actual finalized spec sheet at the naval architect's office ... but it's definitely a hazard that I'm going to be dreading needing to deal with when it's time to draw the full size deck plans for the entire starship.

Too much tonnage allocated aft ... not enough tonnage that can be allocated forward to help "balance" things out in an aesthetically pleasing manner.

Here's hoping that I'm wrong about that and will be able to retain my 3 long x 2 wide proportions that look so beautiful with the 70º aft sweep on the leading edge of the wings.

 

[kilemall]

I wouldn’t dump all that 12 ton work.

That can be the first iteration of your intrepidly smart modular shipyard, they have become a standard in the region and have competitors producing their own module versions.

In the meantime the smart shipyard has worked out the 20 ton version, recapturing the module market and providing shiny new ships. So your universe gets old and new ships and has more depth.

 

[Spinward Flow]

I wouldn’t dump all that 12 ton work.

To be clear ... I'm not dumping it.
I've got it all saved (offline) so that I can use it as reference (and proof of concepts).

That can be the first iteration of your intrepidly smart modular shipyard, they have become a standard in the region and have competitors producing their own module versions.

That's partially the idea/plan/plot involved in the containerized shipping business model.

• You only need type A starports to build the starship(s) with jump drives.
• However, type B starports can build small craft and non-starship big craft ... so long as it doesn't have a jump drive.

This means that you can have more suppliers of the container modules than there are suppliers of the starships (because type B starports aren't as rare as type A starports). That then creates a "surplus imbalance" in the quantity of container modules being produced relative to the number of starships designed to transport them which then helps to "lubricate" the entire interstellar trade system by creating demand for external transport capacity to move all those "extra" container modules.

Also, by "diversifying" the number of suppliers to star systems with type B starports, you increase the number of participants able to invest capital into the containerized shipping business model. You don't have to buy an entire starship ... you can just invest in a Box or a Pod and simply book tickets on starships that can carry them that are "going your way" for where you want your Box or Pod to go.

In the meantime the smart shipyard has worked out the 20 ton version, recapturing the module market and providing shiny new ships. So your universe gets old and new ships and has more depth.

I had the 327 ton J3(2+3)/3G Clipper all written up, formatted and ready to post by the end of last week.
The entire thing weighed in at needing 20 posts (including the Table of Contents that I intended to edit with links for convenience).

And then I got a bright idea for doing a 476 ton J2(2+2)/2G Long Trader version instead ... and accidentally stumbled over the 20 ton vs 12 ton difference in the basic fundamental foundational building block unit for the entire scheme. Even more importantly, I figured out the shape of the deck plan to use for the 20 ton building block ... and the rest is theorycrafting.

Problem is, that theorycrafting is yielding preliminary answers that are TOO GOOD TO IGNORE.
Worse yet, the degree of too good to ignore is sufficient to have me questioning if the "price for high performance" is simply ... too high ... relative to the alternative. I mean, J3 is nice ... but if you don't NEED IT then it's a luxury bordering on vanity which crowds out better and more practical alternatives.

To put it mildly, the answers I'm getting out of the "downgrade" to a J2 Long Trader and switch to a 20 ton Box foundation look like they could very well makes the J3 Clipper with its 12 ton Box stacking feel ... obsolete ... from a merchant seeking profits standpoint.

Just to be clear, I'm sure that the J3(2+3) Clipper would still have its niche roles (such as traversing the Great Rift on the J5 route), but that's a highly specialized use case that gets highly constrained by the distribution of star systems (it's not called the Great Rift for nothing!). But for everything else ... J2(2+2) looks like it is going to be a "better enough" option from a cost to buy, cost to own, cost to operate and even a profit potential standpoint.



Meanwhile, I get to have more fun designing new deck plans for stuff ... using all the tricks, techniques and insights that I've gained getting to this point.


For example, I couldn't make a Configuration: 1, 16 ton Escort Fighter "fit" into the same form factor as a Configuration: 4, 12 ton Box. Traveller does not accept dimensional transcendentalism @ TL=10.

However, by switching over to a Configuration: 4, 20 ton Box ... that offered a form factor that a Configuration: 1, 16 ton Escort Fighter COULD be designed to fit into, increasing the flexibility and interchangeability of hangar space allocation, both on the naval architect's spreadsheet and in the interior design of deck plans! (win win!)



Here's what that redesign of the 16 ton Escort Fighter looks like.

And here's the overlay proof of fitting inside the 7.5x5.5 squares form factor of the basic 20 ton template.

A bit more "chubby/chunky" looking (more of a flying body wedge than a needle this time) than the previous iteration, but I'm really happy with how this redesign of the fighter turned out.

Even go to use my new workflow for making blended swooping curves in the hull silhouette, so I'm really happy with how this one turned out.

 

[Spinward Flow]

Oh, quick addendum to that Escort Fighter deck plan, for anyone who might be skeptical.

I just went into the image and measured the area of the "aft drive bay" to verify I got the size right for a Maneuver-A (1 ton) and Power Plant-A (4 tons) pair of drives. They DO look quite rinky dink in that deck plan, don't they?

Measuring from the middle of the forward, port and starboard bulkheads to the aft edge of the aft bulkhead, I get a (single) rectangular area of 141x270 pixels.

The blank grids I work on are scaled at 60 pixels from the middle of the grey lines (which are 2 pixels wide in each direction) when measuring a single 1.5mx1.5m deck square.

141*270 = 38,070 pixels²
38,070/60/60 = 10.575 deck squares of area
10.575*1.5*1.5*3/14 = 5.098660714285714 displacement tons allocated to drive bays and access spaces

I figure that falls within the +/- 10-20% margin of error allowed when drawing deck plans.

 

[Spinward Flow]

Fun fact.
I was trying to figure out what the shape of the Escort fighter reminded me of, when translating the deck plan into a 3D craft.

Because it is only a single deck (3m) thick, the deck plan view is kind of like this:

But seen from the top (as shown in the deck plan) the silhouette of the outer hull line bears a striking resemblance to this:

So ... bread slice a peach ... take those slices and blend them together in a way that will "melt the heart of a jelly bean" and you get ...

Yeah.
I'm not going to think about this too hard, from now on ...

 

[Condottiere]

 

[Spinward Flow]

I can't believe I missed this bit of "spreadsheet addition" up until now.

Escort Fighter          FE-0106C31-030000-00001-0    MCr28.2304       16 tons
       batteries bearing            1         2                        TL=10.
               batteries            1         2                       Crew=2.
Staterooms=1. Passengers=0. Low=0. Cargo=0. Fuel=1. EP=2. Agility=6. Bridge.
Maneuver-6, Agility-6 @ up to  16 tons total  (+0 tons external)
Maneuver-6, Agility-5 @ up to  20 tons total  (+4 tons external)
Maneuver-6, Agility-4 @ up to  25 tons total  (+9 tons external)
Maneuver-6, Agility-3 @ up to  33 tons total (+17 tons external)
Maneuver-5, Agility-2 @ up to  40 tons total (+24 tons external)
Maneuver-4, Agility-2 @ up to  50 tons total (+34 tons external)
Maneuver-3. Agility-1 @ up to  66 tons total (+50 tons external)
Maneuver-2, Agility-1 @ up to 100 tons total (+84 tons external)
Maneuver-1, Agility-0 @ up to 200 tons total (+184 tons external)

So with a 12 ton Box and/or 96 ton Pod container to "stack" up (jhenga style), it yields the following matrix of possibilities.

Performance	6G, Agility-6	6G, Agility-3	5G, Agility-2	3G, Agility-1	2G, Agility-1	1G, Agility-0
Combined Tonnage	16+0=16	16+12*1=28	16+12*2=40	16+12*4=64	16+12*7=100	16+12*15=196

The problem here is that a 96 ton Pod = 8x 12 ton Boxes ... but as you can see from the chart, the breakpoints for 2G/Agility-1 and 1G/Agility-0 lie at 7 Boxes and 15 Boxes respectively ... neither of which divides neatly into 8.

In other words, there is a "load imbalance" with the choice of a 96 ton Pod ... IF ... one of the design criteria is to be able to externally dock an Escort Fighter with a {insert appropriate tonnage size here} that can still yield a 2G, Agility-1 drive performance out of the A/A drives installed into the Escort fighter. And while the difference between 1G @ 96 tons of external load and 2G @ 84 tons of external load may feel like an "unimportant/marginal" difference ... that kind of step change in drive performance has tremendous implications for "sky crane" ground service support when operating near a world surface in atmosphere under a planetary gravity well of 1G+ (Size: 8+).

The problem with an 84 ton Pod though is that it's 7x 12 ton Boxes ... which doesn't "balance" neatly into a box shape without creating a "notch" somewhere that creates all kinds of problems in packing losses when working in 3D.



All of that changes which shifting over into a 20 ton Box and 80 ton Pod (jhenga) stack.

Performance	6G, Agility-6	5G, Agility-2	3G, Agility-1	2G, Agility-1	1G, Agility-0
Combined Tonnage	16+0=16	16+20*1=36	16+20*2=56	16+20*4=96	16+20*9=196

Can you see what happens there?

12 ton Boxes and 96 ton Pods
16+12*7=100 ... 2G, Agility-1 ... 7 Boxes (8x Boxes = 1 Pod) ... 0 Pods maximum
16+12*8=112 ... 1G, Agility-0 ... 8 Boxes (8x Boxes = 1 Pod) ... 1 Pod maximum
16+12*15=196 ... 1G, Agility-0 ... 15 Boxes (8x Boxes = 1 Pod) ... 1 Pod maximum
16+12*16=208 ... - G, Agility- - ... 16 Boxes (8x Boxes = 1 Pod) ... 2 Pods maximum ... drive performance limit exceeded

20 ton Boxes and 80 ton Pods
16+20*4=96 ... 2G, Agility-1 ... 4 Boxes (4x Boxes = 1 Pod) ... 1 Pod maximum
16+20*9=196 ... 1G, Agility-0 ... 9 Boxes (4x Boxes = 1 Pod) ... 2 Pods maximum

So when it comes to stacking up external load capacity in a symmetrical and load balanced way in both 3D and in the naval architect's spreadsheet, compounding on a basic unit of 20 tons "works better" than compounding on a basic unit of 12 tons.

Of course, I could always modify the 12 ton Box stack into a 72 ton Pod stack (basically 6x Boxes instead of 8x Boxes), but then you wind up with other "emergent weirdness" oozing out of the docking options when you start trying to work with stacking them all up in 3D and trying to conceptualize how the puzzle pieces would have to fit together (and why).



So as a consequence of this (belated ) insight, I'm now leaning in favor of making the 12 ton Boxes and their stacking scheme something of an "abandoned line of development" in my own headcanon ... even though I've been building and experimenting with it for over a year now. The "better symmetry" of the 20 ton Box and 80 ton Pod paradigm is proving to be fruitful in a way that solves a number of edge cases and certain situations requiring ease of form factor exchange equivalents so as to be able to mix 'n' match the contents of hangar/cargo bays with relative ease.

One of those "no fuss, no muss" kinds of deals ... but in this case it's a matter of it being an emergent behavior that results from how the fundamental building blocks "stack" together in usefully symmetrical ways that simplify a LOT of possibilities in favorable ways.



So ... being able to maneuver @ 2G, Agility-1 while the Escort Fighter is docked with a Pod is now a new design requirement ... which means that 96 ton Pods are now "overweight" and no longer fit for purpose.

Glad I was able to work that out before publishing the 327 ton design, otherwise I would have needed to backtrack on that one too ...

 

[Spinward Flow]

Okay ...
I wasn't expecting THAT to happen ...

Working with the 476 ton J2 (and J2+2 requirement) was winding up being ... "too big" ... for deck plan comfort.
I was winding up in the internal hangar bay size range of around ~270-ish tons.
The reason why that's a "problem" is because when you try to do deck plans for that you start winding up with ~12-13x 20 ton Boxes ... and doing those in a single "line" hangar bay nets you at least 6x Boxes of length. At 7.5+0.25=7.75 deck squares per box (to give enough "white space between them to make the iconography work) you're then looking at a hangar bay that is 46.5 deck squares long ... just for the aft hangar bay.

The 327 ton deck plan that you can see earlier upthread is 43.5 deck squares long for the entire ship!

This is why I was thinking that I would need to resort to a "port side/starboard side" dual stack of 20 ton boxes to keep the overall length manageable ... but that makes the deck plan design WIDER in a way that isn't exactly helpful either.



So then the question becomes ... what IS an "acceptable length" of aft hangar bay if doing a single line of double deck height 20 ton Boxes?

And the answer comes back ... either 4 or 5 long ... and 5 is "pushing it" such that the overall deck plan starts looking really elongated and "concorde-ish" in the layout ... but 6 is just "too long" to be believed.

A single file of 4 long, 2 high, 1 wide yields a total of 8x 20 ton Boxes.
A single file of 5 long, 2 high, 1 wide yields a total of 10x 20 ton Boxes.

With a "4 long" stack in the aft hangar bay, a "9th Box berth slot" can overhang forward of the aft hangar bay and be used by the Escort Fighter (which is only 16 tons and fits into the 20 ton Box form factor on the deck plans).
With a "5 long" stack in the aft hangar bay, one of the 10 Boxes gets "deleted" and replaced with the Escort Fighter.

So from a deck plan design constraints standpoint, it's a question of 8 Boxes + Fighter (4 long plus 1 extra spot forward on the upper deck) or of 9 Boxes + Fighter (5 long and subtract one spot on top for the fighter to occupy).

In other words ... does the hangar bay space need to be 180 tons (20*8+20) or does it need to be 200 tons (20*10)?



One of the other engineering constraints involved is that there needs to be enough fuel in the main fuel tanks to execute either a J1 @ 1000 combined tons or a J2 @ 500 combined tons (basically, a "full load") which amounts to a maximum fuel burn of 100 tons per jump. However, since I want the class to be capable of double jumping, there is going to need to be some additional fuel reserve above and beyond "just 100 tons" to cover power plant endurance between wilderness refueling maneuvers.

So if I assume a main tanks fuel load of ~110 tons (for safety margin) which cannot be meaningfully reduced much further (it can, but things start getting potentially dicey) ... then I wind up with the following computational outcomes on the naval architect spreadsheet:

• 55 tons for E/E/E drives
• 110 tons for main fuel tanks
• 8 tons for TL=10 fuel purification plant
• 20 tons for bridge
• 4 tons for model/2fib computer
• = 197 tons

If I add a 200 ton (10x 20 ton berth slots) internal hangar bay, the design is weighing in at almost exactly 400 tons.
If I add a 180 ton (9x 20 ton berth slots) internal hangar bay, the design is weighing in at almost exactly 380 tons.

What's significant about those 2 break points is that both options do VERY INTERESTING THINGS when the starship is configured for double jumping ... or even triple jumping!



Note that one available option would be a "4 long+1 more" = 180 tons hangar bay ... but done in a 400 ton hull, which would leave 20 tons of space to allocate elsewhere in the starship.



I'm thinking that a GCarrier (8 tons) and a Speeder (6 tons) would be a good idea for vehicle support, especially for passenger pickup/drop off and even simple "touring" as a group as a side line business opportunity/draw.

That would leave another 6 tons available ... and my personal preference would be for a Mail Vault (5 tons) and a Magazine (1 tons, 20 missile or sand cannisters combined capacity) to have enough of an ordnance reserve for the Escort Fighter.

I'm liking this version with vehicles a lot more than I thought I would, since it makes for a superior ACS build and enhanced adventuring (or just safari touring) potential option, so I think I'll go with that.



All that work, just to land on 400 tons in the end.

It's like a Type-R class Subsidized Merchant ... BUT BETTER.

 

[Grav_Moped]

I just went into the image and measured the area of the "aft drive bay" to verify I got the size right for a Maneuver-A (1 ton) and Power Plant-A (4 tons) pair of drives. They DO look quite rinky dink in that deck plan, don't they?

That's a relic from the '77 rules. The M-Drive was just the thrust-producing accessory to the fusion power plant -- a rocket nozzle for the exhaust, as it were.
And look at real-world rockets from that era (and in the present, as well): the engines don't take up that much space in the whole stack. It's pretty much all fuel tanks...

LBB5 made them all bigger, especially the lower-TL power plants. LBB2 (especially '81) forced its design tradeoffs with MCr and the fuel tank size, LBB5 did it with drive size and MCr (except for the M-Drive which is cheap per Td).

 

[Spinward Flow]

That's a relic from the '77 rules. The M-Drive was just the thrust-producing accessory to the fusion power plant -- a rocket nozzle for the exhaust, as it were.
And look at real-world rockets from that era (and in the present, as well): the engines don't take up that much space in the whole stack. It's pretty much all fuel tanks...

So ... TL=10 HEPlaR ...?
Before it became known as HEPlaR.

LBB5 made them all bigger, especially the lower-TL power plants. LBB2 (especially '81) forced its design tradeoffs with MCr and the fuel tank size, LBB5 did it with drive size and MCr (except for the M-Drive which is cheap per Td).

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.