Pondering starship evolution

Spinward Flow said:

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.

Click to expand...

Here's the preliminary Proof of Concept™ for the 8x Boxes contents of the aft hangar bay before enclosing the space(s) in bulkheads.
Upper deck above, main deck below (in case anyone was wondering), although this could potentially be reversed depending on how the rest of the starship deck plan pans out.



Fun little bits of trivia:

• 4x 12 ton (5x5 deck squares) Boxes in a row for the 327 ton J3(2+3) version measured 21x5.5=115.5 squares in area per deck when enclosed.
  • 115.5*1.5*1.5*3/14=55.6875 ≈ 55.7 tons displacement per deck for 4x 12 ton Boxes (55.7 is 116% of 4*12*1.0=48)
• 4x 20 ton (7.5x5.5 deck squares) Boxes in a row for the 388 ton J2(2+2) version measure 31x6=186 squares in area per deck when enclosed.
  • 186*1.5*1.5*3/14=89.67857142857143 ≈ 89.7 tons displacement per deck for 4x 20 ton Boxes (89.7 is 101.9% of 4*20*1.1=88)

So already, the "+10% tax" on tonnage (that I adopted up thread) to be put into hangars by sub-craft modification is yielding a far more intellectually honest answer in the naval architect's spreadsheet accounting than the previous "stored at own tonnage" (100%) accounting used in LBB5.80 RAW.

This pleases me.

Y'know ... sometimes seeing is believing ... and sometimes, seeing can make comparisons easier to believe.

Here's what happens if I overlay my new 20 tons Boxes in "hangar bay arrangement" to be used in the 388 ton Long Trader class on top of the deck plans I did for the 327 ton Clipper class. The aft end of the Boxes is aligned to the same longitudinal distance inside the hull.

Makes for quite the difference, doesn't it?

I may wind up needing to use an 80º aft sweep on the leading edge wing roots this time, instead of a 70º aft sweep like you can see above. Might have to do an 80º aft sweep forward that transitions into a 70º aft sweep around the transverse port/starboard access corridor or something. Bare minimum, this redesign is going to make for a LONG deck plan.

Eh ... we'll burn that bridge when we get to it.

Time for another deck plan update.

Managed to get all the "fiddly bits" work done adjusting the spacing between the Boxes in the hangar bay (now sized at 11 pixels between bulkheads) which then made it possible to "squarely fit" the bulkhead lines of the outer walls onto the grid map at exactly 240 pixels apart (6 deck squared wide) from port bulkhead center to starboard bulkhead center (the bulkheads themselves are 4 pixels thick).

At 40 pixels per 1m, this gives a 27.5cm "crawlspace" around and between the Boxes, and which then becomes the "margin of error" when loading and unloading Boxes into the hangar bay.



The trapezoidal carveouts in the hangar bay walls are for robotic manipulator arms to assist with docking/undocking as well as loading/unloading operations. There are 2 such arms (port+starboard) for each Box berth in the hangar bay. The docking assist arms are typically controlled from a workstation on the bridge, often operated by the Service Department's Steward in their operational capacity of supercargo (among other duties).

The "funny little grey square pimples" placed asymmetrically on either side of each berthing cell is the storage locker space for a 10 ton Collapsible Fuel Tank. Since the aft hangar bay space hosts 8x 20 ton Boxes, there are 16x 10 ton capacity Collapsible Fuel Tanks (2 per Box berth). The Collapsible Fuel Tank storage lockers are positioned such that the port/starboard manual hatches on Cargo Boxes and/or Environment Boxes can be left OPEN ... allowing each 10 ton capacity Collapsible Fuel Tank to fill half a Cargo and/or Environment Box while those boxes are berthed internally (using their interior space for the fuel bladder to expand into). When Boxes are moved to external docking points outside the starship's hull, the fuel bladders can expand into the empty hangar space, allowing flexible choices in how much hangar space to devote to additional fuel reserves rather than loading up the hangar bay space with major/minor/incidental cargo lots for transport.

Note: If the hangar bay is being used to store and transport cargo, the hangar bay(s) should not be depressurized and opened to space until delivery of such cargoes can be made at the destination they are bound for. Cargoes loaded into Boxes are not subject to this limitation to operations.

One of the things that I like about this newest iteration of the aft hangar bay and its enclosure is that each "berth space" has an interchangeable set of features (the docking arms, the collapsible fuel tank lockers). This means that no location within the hangar bay is bespoke intended for a specific type of Box exclusively ... although for operational reasons, the layout I'm presenting her is likely to be the most optimal arrangement when all Boxes are stored internally (for reasons various and sundry).

The forward hangar bay on the upper deck for hosting the Escort Fighter will once again be segregated from the aft (double deck) hangar bay so as to permit the launching and recovery of the Escort Fighter without needing to depressurize the entire aft hangar bay (which would be an operational hassle if it were necessary to launch/recover the Escort Fighter).

The hangar bay aft door is a single piece, hinged at the bottom, which when lowered can be used as a ramp for loading and unloading Boxes into the aft hangar bay, aided by the starship's landing gear "kneeling" to bring the aft ramp closer to a world surface.



Yes, I'm liking how this is shaping up, so far ...

Huh.
Well there's an option I wasn't expecting.

Was thinking about yet more build configurations based on the 20 ton Boxes (and the need to berth them at 110% displacement, now) ... and thinking back on my 327 ton J3/3G Clipper design ...

Hey, wait a minute.
The original design spec for that was 8x 12 ton Boxes (96 tons) plus 1x 16 ton Escort Fighter to occupy its hangar bays.
The tonnage budget for that was 16+8*12=112 tons of hangar bay, plus a little extra to add in some collapsible fuel tank capacity (in the hangar bay, as opposed to in the non-existent cargo hold).

But in the "new" 110% tonnage for small craft paradigm, 5x 20 ton Boxes is 5*20*1.1=110 tons of hangar bay with a capacity of 100 tons of craft.
That means that it's possible to do 4x 20 ton Boxes plus 1x 16 ton Escort Fighter in those "5 slots" of berthing spaces.

1. Escort Fighter (16 tons, 4 tons of capacity unused)
2. Stateroom Box (20 tons, 5 staterooms)
3. Stateroom Box (20 tons, 5 staterooms)
4. Laboratory Box (20 tons, Environmental Control: Type: V-c can support 10 people)
5. Cargo Box (20 tons)

Returning to the original crew of 7, that would yield a revenue tonnage fraction of 3x high passengers and 20 tons of cargo in a J3/3G "clean" configuration. The "old" 100% tonnage for small craft paradigm allowed for 5x high passengers and 24 tons of cargo at the same J3/3G drive performance point in a 327 ton hull. So a noticeable downgrade in high passengers (-2) and cargo capacity (-4 tons) ... but that's only when operating at the most limited edge of J3/3G output. Fall back to J2/2G and the cargo capacity goes UP ... by +100 tons internally, plus whatever charters can be had for the additional external load capacity.



Maybe the J3/3G Clipper isn't "dead" as a design option after all ... it's just restin' ...



Hmmm, that case, let me see ...

The reason for the 327 ton hull choice was that 327*1.1=359.7≈360 tons ... which then neatly divided by 12 into 30x 12 ton Boxes, preventing "stacking inefficiencies" elsewhere if one ship of the class needed to tow a second one (for whatever reasons).

1000-333=667/1.1=606.3636 ≈ 606 tons external craft load capacity @ J1
500-333=167/1.1=151.8181 ≈ 151 tons external craft load capacity @ J2

However, staying at 327 tons ...

1000-327=673/1.1=611.8181 ≈ 611 tons external craft load capacity @ J1
500-327=173/1.1=157.2727 ≈ 157 tons external craft load capacity @ J2

But if I can somehow get all the way down to 324 tons ...

1000-324=676/1.1=614.5454 ≈ 614 tons external craft load capacity @ J1
500-324=176/1.1=160 ≈ 160 tons external craft load capacity @ J2

Or if I nudge upwards into 328 tons again ...
1000-328=672/1.1=610.9090 ≈ 610 tons external craft load capacity @ J1
500-328=172/1.1=156.3636 ≈ 156 tons external craft load capacity @ J2

The thing is ... 156 and 157 tons of external small craft load capacity amounts to 1x 16 ton Escort Fighter and 7x 20 ton Boxes docked and being towed externally, which would mean 3x 20 ton Boxes owned by Third Parties chartering the external load capacity plus the 4x 20 ton Boxes owned by the operator @ J2.

160 tons of external small craft load capacity amounts to 8x 20 ton Boxes docked and being towed externally, which would mean 4x 20 ton Boxes owned by Third Parties chartering the external load capacity plus the 4x 20 ton Boxes owned by the operator @ J2.

J3 and J2+3 drive performance still remains a bottleneck to revenue tonnage, but J2 and J2+2 can be accomplished with comfortable profit margins and remarkably adequate cargo capacity for moving speculative goods.

Maybe the J3/3G Clipper isn't "dead" as a design option after all ... it's just restin' ...

Click to expand...

Maybe it IS just restin' ... waiting for a new design to revive it.

Spinward Flow said:

Time for another deck plan update.

Click to expand...

Built out more of the main deck.

I'm really liking how this is coming together.

Obviously haven't installed the drives yet.
Going to need to do the S-curve from the end of the drive bays to the aft end of the hangar deck, so there's still plenty to do before moving towards the forward end of the main deck.

Spinward Flow said:

Time for another deck plan update.

Click to expand...

Things are really starting to look intentional by this point.
Obviously almost all of the design cues are coming from previous iterations on this exact same theme of "how to build a starship" like this.

Decided to remove the "demountable fuel tanks around the engineering workstations" that I'd used previously and just reclaim that volume for the integral main fuel tank.

I like how the "linear E/E/E drive bays" arrangement works out for this J2/2G variation on the theme.
Still have the Makertech Workshop and engineering tools locker the previous iteration, but this time there's a better utilization of space inside the hull by flipping their position to be outboard with the engineering workstation inboard (surrounded by fuel in the fuel tanks.

The fuel purification plant and "waste chemistry feedstocks bunkers" forward of the transverse access corridor remain largely unchanged. I'll need to "measure" where the forward Grav Lift up into the Escort Fighter berth needs to go in order to figure out how far forward the bridge will need to be placed.

Going to be interesting to see where the landing gear needs to go this time ... and how much of it will be needed to keep the ground pressure down enough to touch down (safely) at austere unprepared landing sites with little to no ground support services or infrastructure (worth mentioning).



Overall, the impression even at this stage is of a deliberately linear design for the deck plans, making the starship long and thin.

Still worried about the beam width of that transverse corridor.
In previous deck plans, it was 13 deck squares wide ... and now it's 15 deck squares wide at the outboard grav lifts, which has implications for how the wings need to be shaped.

Spinward Flow said:

Time for another deck plan update.

Click to expand...

The Upper Deck and Main Deck internal habitable spaces are now "mostly" complete, barring some additional tweaks and details that remain to be filled in for the sake of completeness to get the fiddly bits just so.

And here's what it looks like when the Upper Deck is overlay stacked on top of the Main Deck, to make sure that everything aligns properly.

Obviously, this is all before detailing the outer hull silhouette shape for the wings that contain most of the fuel tankage (101 tons of fuel for this design). May wind up with some "slender thickness" wings, rather than the more typical 3m thick (1 deck height) wings.

Deciding where the landing gear is going to go will also be kind of interesting to see. Most of the ship's mass resides in the aft hangar bay (which consumes 200 tons out of the 388-390 ton "spreadsheet budget" for the class. The way the spreadsheet math is adding up, I may need to resort to a 390 ton hull just to make everything fit with sufficient margin for multi-jump without refueling operations.

Spinward Flow said:

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.

Click to expand...

Yeah.
388 tons is DOABLE ... but hella risky with too little margin for error (or mishap).



But ...
If I scale up to 410-412 tons (the "next step up" that fits with the small craft building block sizes), I get ... THIS ...

---

(4*20)*1.1 = 88 tons (4x Boxes can be docked externally and retain J2)
500-88 = 412 tons starship hull max displacement

410 tons starship hull

• 55 tons for LBB2.81 standard E/E/E drives (code: 2)
• 104 tons of total fuel: 410 tons @ J2 = 82 tons jump fuel + 22 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=181.81 tons of hangar berths capacity
  1. Escort Fighter = 16 tons (4 tons unused 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. Environment Box = 20 tons
  9. Cargo Box = 20 tons
  10. 180 tons capacity Collapsible Fuel Tanks = 1.8 tons
• 8 tons for GCarrier
• 6 tons for Speeder
• 5 tons for Mail Vault

= 55+104+8+20+4+200+8+6+5 = 410 tons

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1000 - 410 = 590 / 1.1 = 536.3636 ≈ 536 tons of external load capacity for small craft tonnage
16+(26*20) = 536 tons of small/big craft tonnage
536-410 = 126 tons of small/big craft tonnage capacity remaining when "buddy towing" an inactive ship of the class

1. 410+(16+(26*20))*1.1 = 999.6 ≈ 1000 tons @ J1 = 100 tons jump fuel
2. 410+(0+(22*20))*1.1 = 894 ≈ 894 tons @ J1 = 89.4 tons jump fuel
3. 410+(0+(18*20))*1.1 = 806 ≈ 806 tons @ J1 = 80.6 tons jump fuel

100+89.4=(189.4) + 80.6=270 tons total jump fuel
104+(180)-270=14 tons fuel available for power plant during voyage

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500 - 410 = 90 / 1.1 = 81.8181 ≈ 81tons of external load capacity for small craft tonnage
(4*20) = 80 tons of small craft tonnage

1. 410+(0+(8*20))*1.1 = 586 ≈ 586 tons @ J1 = 58.6 tons jump fuel
2. 410+(0+(4*20))*1.1 = 498 ≈ 498 tons @ J2 = 99.6 tons jump fuel
3. 410+(0+(0*20))*1.1 = 410 ≈ 410 tons @ J2 = 82 tons jump fuel

58.6+99.6=(158.2) + 82=240.2 tons total jump fuel
104+(160)-240.2=23.8 tons fuel available for power plant during voyage

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Now THAT is looking a LOT more fuel secure and mission flexible (because of the vehicles) @ 410 tons of starship displacement. It loses the ability to "tow" a Scout/Courier (or any other 100 ton craft) @ J2/2G, but I'm thinking that the added fuel capacity, vehicles and mail vault will more than make up for that.

It would mean altering the deck plan I've worked up for the Main Deck to accommodate the changes, but on balance I think that would probably be a positive, rather than a negative. Easiest thing to do would be to move the fuel purification plant(s) so as to have access to the vehicle berths (GCarrier and Speeder) through the transverse corridor (port/starboard) on the main deck. The vehicle berths would need to be outboard of the overhanging Upper Deck hull spaces in order to have a clear space on the dorsal side of a wing for a launch or recovery ... or if the wing root is thick enough there, could do a horizontal launch/recovery through a door in the leading edge of the wing.

Bare minimum, more edits to spreadsheet data and deck plans will need to happen.

If I'm going to be adding vehicles to my deck plans, I'm going to need some Geomorphs iconography (slightly modified) added to my library of parts in order to make that happen.



8 ton G-Carrier (MCr1, TL=8+) (LBB3.81, p23)


6 ton Speeder (MCr1, TL=8+) (LBB3.81, p23)


4 ton Air/Raft (MCr0.6, TL=8+) (LBB3.81, p23)


Yeah, that looks good.

Confusing thing about the GCarrier is that it's only 2.1m tall, not the more typical 2.5-3m of deck height that we're used to, making it look longer and wider on deck plans than you might otherwise expect to see.

Spinward Flow said:

Time for another deck plan update.

Click to expand...

And ... here's what happens if I have to move the fuel purification plants further forward so as to have enough space to add in a 6 ton Speeder berth, a 5 ton Mail Vault and an 8 ton GCarrier berth forward of the transverse corridor that was already in the design previously. There will be vehicle berth doors in the leading edge of the port wing (not yet added, for somewhat obvious reasons) allowing for horizontal launching and recovery of the GCarrier (the Upper Deck overhangs the GCarrier's berth space too much to permit a vertical launch and recovery). The Speeder will have a door in the dorsal surface of the starboard wing for vertical launches and recoveries, because its vehicle berth is far enough outboard to clear the Upper Deck hull silhouette.

Makes the Main Deck a LOT LONGER longitudinally, but in the context of other changes necessary to make the 410 ton redesign work, it makes a lot of sense at this stage.



Kept the idea of "waste chemistry feedstock bunkers" in between the ... segments ... of the TL=10 fuel purification plant (8 tons) and put that space to use getting the compartment spaces to "even up" after the "odd shapes" needed for the Speeder+Mail Vault+GCarrier so as to make them fit on the deck plan, properly.



One side effect of doing all of this though is ... I realized I needed more crew.
Well, to be more specific ... I needed more vehicle crew ... meaning, I needed more Ship's Troops.

Originally, I'd added *1* Ship's Troops (a corporal) to the crew roster so as to reduce the number of Stewards that I would need for the regenerative biome life support laboratory choice of Environmental Control: Type V-d.

• 3 / 1000 * 410 = 1.23 ... round up because Environmental Control: Type V-d
  • ≈ 2 Steward positions required for crew, unavailable for high passenger services
  • 0 Ship's Troops
• 2 / 1000 * 410 = 0.82 ... round up because Environmental Control: Type V-d
  • ≈ 1 Steward position required for crew, unavailable for high passenger services
  • 3 / 1000 * 410 = 1.23 ≈ 1 Ship's Troops, minimum

However, looking at the vehicles and thinking about the "lean manning/skilled crew" personnel management model that the class was relying on, I realized that the vehicles really needed their own crew (driver+gunner for the GCarrier and driver for the Speeder). That way, both vehicles could be operated independently of the Long Trader (or the Escort Fighter) without depriving the starship of necessary crew.

The solution?
Increase the number of Ship's Troops from 1 to 3 ... so as to provide a crew of 2 (corporal: commander/gunner, lance corporal: driver) for the GCarrier and a crew of 1 (lance corporal: driver) for the Speeder.

• 410 / 3 = 136.667 ≈ 1 Ship's Troops per 136 tons when unencumbered by external loads clean displacement @ J2
• (410+16+26*20) / 3 = 315.333 ≈ 1 Ship's Troops per 315 tons when maximally encumbered by external loads @ J1

Doing that increased the total crew compliment from 8 to 10 and reduced the high passenger accommodations from 7 down to 5 (a single Stateroom Box, as it turns out ), but the inclusion of a Mail Vault to help defray operational expenses makes up for that loss in passenger ticket revenues by making deliveries of X-Mail.

Having an actual security team as part of the crew will make a variety personnel entrapment tactics while the starship is berthed at a starport a bit more problematic for an attacker, due to the presence of ship's troops on the crew roster for security (including when the crew takes liberty on worlds between jumps).

It also means that the class just got that much better when converted to a Patrol Ship, Safari Ship or even a Yacht, due to the inclusion of onboard security and grav vehicles enhance the mobility of personnel away from the starship.



Me likey.

Spinward Flow said:

Time for another deck plan update.

Click to expand...

Redid the nose cone in the forward avionics bay.
Measuring the overall length now adds up to 90.5m (60.333 deck squares long) of interior spaces.
Once I wrap the fuel tanks around the main deck bulkheads, the total overall length of the starship will probably increase ... but I'll deal with that tomorrow. Getting the fuel scoops and wing sweep JUST RIGHT is going to be something of a challenge.

Spinward Flow said:

Time for another deck plan update.

Click to expand...

Yeah.
That'll play.



And here's what it looks like when the Upper Deck is overlaid on top of the Main Deck ... to check for alignment issues (you know the drill).



Main Deck length: 85.5m
Wingspan width: 45m
Hull height: 7m (+1.5m w/landing gear down)
Length to width ratio: 1.9:1
Total displacement with no external loading: 410 tons

The wing silhouette turned out to be quite a bit different from what I was expecting to see.
Somehow, it wound up looking more like the wing shapes of a J-37 Viggen crossed with a F-16XL through some kind of "unfortunate engineering accident" (that might result in superpowers if genre aware).

---

Anyone who has been following this thread will notice that I made a major change to the "midship area" of the Main Deck between the transverse corridor and the bridge. I wasn't liking how the various shapes were adding up together to push the bridge so far forward.

Added manual hatch (in case of complete power failure affecting iris valves) egress routes from both the bridge and the engineering drive bays. I view this as something of a safety regulations kind of thing, to prevent crew from becoming trapped by a "one way in or out" type of deck plan layout.

Murphy's Laws of Combat
Make it tough enough for the enemy to get in and you won't be able to get out.

Click to expand...

How does it feel to have reached this point in the design and documentation process?
A bit like this.

Spinward Flow said:

Time for another deck plan update.

Click to expand...

Decided that I didn't like the silhouette shape of the wings (too much "lawn dart" impression).
Experimented with adjusting the shape of the wingtips and trailing edges of the wings. Now the silhouette of the wings manages to look more like a "notched cranked arrow" type of planform.
Fun Fact: The "interruption notches" for the vehicle bays basically amount to "cutouts" in the general 70º aft sweep angle of the leading edge from the fuel scoops all the way back to the wing tips (I checked, the forward and mid-wing sections align almost perfectly, despite the "interruption" of the vehicle bays with their pressure doors).

One immediate side effect of doing this was that I needed to redesign the aft egress from the decontamination airlocks at the aft end of the drive bays. I would prefer to think that I was substantially successful in tweaking those parts of the interior design.

Did a little more cleanup (on aisles 2 and 3) so the decontamination airlock lettering at the ends of the transverse corridor aren't quite so "cramped in the corner" in order to make them fit.

Also redid the outer bulkhead shape of the nosecone to make it "fit" better with the overall design aesthetic of the deck plan conventions.

Individual deck plans (separated):



Vertically overlaid deck plans (alignment/sanity check):



Main Deck length: 85.5m
Wingspan width: 54m
Hull height: 7m (+1.5m w/landing gear down)
Length to width ratio: 1.58333:1
Total displacement with no external loading: 410 tons

NOW we're cooking with magnetic induction and heat pumps!

The radar dish should be replaced with a phased array...

kidding, it is an excellent project you have been sharing with us.

mike wightman said:

The radar dish should be replaced with a phased array...

Click to expand...

You're RIGHT, of course.

mike wightman said:

kidding

Click to expand...

mike wightman said:

it is an excellent project you have been sharing with us.

Click to expand...

I'm doing it partly for peer review ("oops, you missed this bit"), in the "laying cards on the table" sense of things ... while at the same time being a demonstration of the Creative Process™ that can go into a project like this. The first draft rarely looks like the final draft and there are going to "options" along the way for how to do things (mathematically, artistically, etc.) that feed back into each other (spreadsheet math influences deck plan design and vice-versa) in ways that can "reverberate" through the design of a class.

Another reason for doing all of this is that it demonstrates (step by step) the thinking process(es) involved in this kind of creation, along with all of the second guessing, repeated questioning of assumptions, continuing "churn" in the value proposition of what are "optimal" choices to make ... and so on and so forth. This thread therefore becomes a repository for the "history" of how something like the sausage this particular ship class got made and why it takes the form that it does and why the mathematics of it "dictate" the way everything turned out.

In other words, I'm not just "picking" hull displacement tonnage numbers that do NOT divide by 100 for arbitrary reasons ... but rather that those "weird tonnages" I keep landing on are a product of the confluence of factors that go into deciding what goes INTO the design of a starship and what must be left OUT of it. Build the "insides first" and then wrap all the percentage based stuff around it until settling upon a "balance point" that satisfies multiple criteria.

Best possible outcome would be that someone else, at some point, gets inspired by what I've been doing enough to "follow the roadmap" that I've highlighted here and decides that they want to build their own Dream Starship™ too, complete with deck plans and all the trimmings. Being able to inspire someone else into wanting to do this kind of creative effort too would be the ultimate reward for my efforts.

The penultimate reward would be if there is any demand for using the results of my (unpaid) labors in Traveller campaigns ... whether they are set in the Spinward Marches or elsewhere. This specific starship class that I am building is a TL=10 J2/2G effort that relies on LBB2.81 standard drives and turret/sandcaster/missile equipment fittings as much as possible, meaning that there isn't anything particularly "unique or special" about the design itself ... aside from the Systems Integration (which is always the hardest part of any complex engineering project). The component technologies that go into the starship and its small craft are "nothing special" in and of themselves ... but how they get put together to reach the "balance point" that they do when fully assembled is what makes the starship class "something special" for naval architects, shipyards, owners and operators as well as competitors and adversaries.

The parts are "bog standard" TL=10 ordinary.
The assembly of them into their final form yields capabilities that are anything BUT ordinary.

And THAT is Good Engineering.

Spinward Flow said:

Maybe the J3/3G Clipper isn't "dead" as a design option after all ... it's just restin' ...

Click to expand...

Continuing to question the Analysis of Alternatives (AoA) ...

(8*20)*1.1 = 176 tons (8x Boxes can be docked externally and retain J2)
500-176 = 324 tons starship hull displacement

324 tons starship hull

• 55 tons for LBB2.81 standard E/E/E drives (code: 3)
• 128 tons of total fuel: 322 tons @ J3 = 97.2 tons jump fuel + 30.8 tons power plant fuel
• 8 tons for TL=10 fuel purification plant (200 ton capacity is minimum)
• 20 tons for bridge
• 2 tons for model/2bis computer
• 111 tons for 111/1.1=100.909≈100.9 tons of hangar berths capacity
  1. Escort Fighter = 16 tons (4 tons unsued to achieve form factor commonality with 20 ton Boxes, available for 4 tons of collapsible fuel tank reserve)
  2. Stateroom Box = 20 tons
  3. Stateroom Box = 20 tons
  4. Laboratory Box (life support, Type: V-c) = 20 tons
  5. Cargo Box = 20 tons
  6. 80 tons capacity Collapsible Fuel Tanks = 0.8 ton

= 55+128+8+20+2+111 = 324 tons

---

1000 - 324 = 676 / 1.1 = 614.5454 ≈ 614 tons of external load capacity for small craft tonnage
0+(30*20) = 600 tons of small/big craft tonnage
614-324 = 290 tons of small/big craft tonnage remaining when "buddying towing" an inactive starship of the same class

1. 324+(0+(30*20))*1.1 = 984 ≈ 984 tons @ J1 = 98.4 tons jump fuel
2. 324+(0+(26*20))*1.1 = 896 ≈ 896 tons @ J1 = 89.6 tons jump fuel

98.4+89.6=188 tons total jump fuel
128+(80)-188=20 tons fuel available for power plant during voyage

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500 - 324 = 176 / 1.1 = 160 ≈ 160 tons of external load capacity for small craft tonnage
(8*20) = 160 tons of small craft tonnage

1. 324+(16+(10*20))*1.1 = 561.6 ≈ 562 tons @ J1 = 56.2 tons jump fuel
2. 324+(0+(8*20))*1.1 = 500 ≈ 500 tons @ J2 = 100 tons jump fuel

100+56.2=156.2 tons total jump fuel
128+(56)-156.2=27.8 tons fuel available for power plant during voyage

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500 - 324 = 176 / 1.1 = 160 ≈ 160 tons of external load capacity for small craft tonnage
(8*20) = 160 tons of small craft tonnage

1. 324+(0+(8*20))*1.1 = 500 ≈ 500 tons @ J2 = 100 tons jump fuel
2. 324+(0+(4*20))*1.1 = 412 ≈ 412 tons @ J2 = 82.4 tons jump fuel

100+82.4=182.4 tons total jump fuel
128+(80)-182.4=25.5 tons fuel available for power plant during voyage

---

500 - 324 = 176 / 1.1 = 160 ≈ 160 tons of external load capacity for small craft tonnage
(8*20) = 160 tons of small craft tonnage

1. 324+(0+(4*20))*1.1 = 412 ≈ 412 tons @ J2 = 82.4 tons jump fuel
2. 324+(0+(0*20))*1.1 = 324 ≈ 324 tons @ J3 = 97.2 tons jump fuel

82.4+97.2=179.6 tons total jump fuel
128+(80)-179.6=28.4 tons fuel available for power plant during voyage



The downside of this formulation (@324 tons) is that the concept has been reduced to just being a "container truck" that carries 3 high passengers and 20 tons of cargo (internally) @ J3/3G. Even subsidized, that's a revenue stream of only Cr50,000 in tickets per jump, yielding a mere Cr25,000 to the operator (after 50% subsidy rake) for covering overhead expenses.

Quick bit of napkin math "to determine the damage" to profitability @ J3/3G yields:
Single Production (100%) Cost: MCr170.474 + 35.288 + (3.964+3.1712) + (5.464) + (1.464) = Cr219,825,200
Volume Prouction (80%) Cost: MCr136.3792 + 28.2304 + (3.1712*2) + (4.3712) + (1.1712) = Cr176,494,400

Subsidized Break Even Point @ 25 Destinations Per Year: Cr24.402

That would mean that under subsidy, with only 3 high passenger tickets and 20 tons of cargo moving @ J3, an operator would be making a Cr598 PROFIT per J3 jump. Note that an interstellar charter for the same capacity would yield a Cr1902 LOSS per J3 jump. Of course, an operator willing to forego 5 tons of cargo ticket capacity in favor of Mail Contracts (Cr25,000 per destination) would EASILY be able to turn a profit on 3 high passengers and a mere 15 tons of cargo capacity @ J3 yielding a Cr10,598 PROFIT per J3 non-charter (or Cr8,348 PROFIT per J3 charter).

Now, no one is going to be "hiring people to do the raking" for all the credits coming in at THAT rate of profitability ... but that would be the absolute WORST rate of profit margin when the ship is loaded for the longest jumps. The important point being here that even if you have to "grind things out on the margins" it's possible to shave credits and still operate in the black (barely) while under subsidy and serving extremely low population (4-) world markets with severely limited demand for ticket services.

However, if you want to make BIG profits, shorter range (J1-2) and heavier loads will EASILY yield much greater profit yields.

But once again, because of the lack of vehicle berths in the design, the starship becomes essentially a "starport to starport delivery merchant" rather than being something that could be gainfully employed in a variety of non-transport roles (such as safari touring, for example).



So although the 324 ton J3/3G option CAN WORK (just barely) on E/E/E drives, it unfortunately suffers from being "just a bit too cramped" (still) and wanting to be a larger starship with more powerful drives.

Upgrading to F/F/F drives and 400 ton J3/3G option might work better, since it would increase the hangar bay fraction for 20 ton Boxes.

Spinward Flow said:

Maybe the J3/3G Clipper isn't "dead" as a design option after all ... it's just restin' ...

Click to expand...

500 tons starship hull

• 85 tons for LBB2.81 standard H/H/H drives (code: 3, TL=10)
• 180 tons of total fuel: 500 tons @ J3 = 150 tons jump fuel + 30 tons power plant fuel
• 8 tons for TL=10 fuel purification plant (200 ton capacity is minimum)
• 20 tons for bridge
• 2 tons for model/2bis computer
• 200 tons for 200/1.1=181.8181≈181.8 tons of hangar berths capacity
  1. Escort Fighter = 16 tons (4 tons unused to achieve form factor commonality with 20 ton Boxes, available for 4 tons of collapsible fuel tank reserve)
  2. Stateroom Box = 20 tons
  3. Stateroom Box = 20 tons
  4. Stateroom Box = 20 tons
  5. Laboratory Box (life support Type V-d) = 20 tons
  6. Laboratory Box (life support Type V-d) = 20 tons
  7. Laboratory Box (life support Type V-d) = 20 tons
  8. Environment Box = 20 tons
  9. Cargo Box = 20 tons
  10. 180 tons capacity Collapsible Fuel Tanks = 1.8 ton
• 5 tons for Mail Vault

= 85+180+8+20+2+200+5 = 500 tons

• 10 crew (Cr34,860 monthly salaries)
  • 2x Pilot, Navigator, (chief) Engineer/Engineer, Engineer, Steward/Steward, Medic, Gunner, 2x Ship's Troops (corporal, lance corporal)
• Revenue Tonnage = 5 high passengers, 20 tons cargo, 20 tons environmentally sensitive cargo, 5 tons mail

Growing the design from 410 tons J2/2G up to 500 tons J3/3G would mean needing to drop the vehicle berths ... but there's external loading room for 1x 20 ton Box to be optionally transported outside the hull on the centerline while retaining J3/3G performance, and that extra Box could include vehicle berths (1x GCarrier, 1x Speeder, 1x Air/Raft = 18 tons ... or ... 1x GCarrier, 2x Speeder = 20 tons)


This would basically mark the "outer boundary" of what can be done using TL=10 LBB2.81 standard drives (since J+ are TL=11+).



External load capacity @ J2 would expand from 500-410=90/1.1=81.8=4x 20 ton Boxes ... up to an external load capacity @ J3 of 800-500=300/1.1=272=13x 20 ton Boxes.

External load capacity @ J1 would expand from 1000-410=590/1.1=536=1x 16 ton Escort Fighter + 26x 20 ton Boxes ... up to an external load capacity @ J1 of 1600-500=1100/1.1=1000=50x 20 ton Boxes.

410 tons @ J2/2G = 4x 20 ton Boxes external load
500 tons @ J2/2G = 13x 20 ton Boxes external load
+21.95% hull displacement, +225% external load capacity @ J2

410 tons @ J1/1G = 1x 16 ton Escort Fighter + 26x 20 ton Boxes external load
500 tons @ J1/1G = 50x 20 ton Boxes external load
+21.95% hull displacement, +86.57% external load capacity @ J1

E/E/E drives = 55 tons, MCr110, requires 2 engineering crew positions
H/H/H drives = 85 tons, MCr176. requires 3 engineering crew positions

Spinward Flow said:

Maybe the J3/3G Clipper isn't "dead" as a design option after all ... it's just restin' ...

Click to expand...

And "gaining weight" apparently ...

Spinward Flow said:

Maybe the J3/3G Clipper isn't "dead" as a design option after all ... it's just restin' ...

Spinward Flow said:

And "gaining weight" apparently ...

Click to expand...

Click to expand...

A preliminary analysis of alternatives between the 410 ton J2/2G design (Cr198,292,800 construction cost in volume production) and a 500 ton J3/3G design (Cr262,580,800 construction cost in volume production) ... shows that although the "larger, more (drive) powerful" version is Cr64,288,000 more expensive in volume construction cost, for an additional +90 tons of hull.

410 ton J2/2G Long Trader + 16 ton Escort Fighter + 8x 20 ton Boxes = 586 tons of hull metal

• 198,292,800 / 586 = Cr338,384 per ton construction cost in volume production

500 ton J3/3G Long Trader + 16 ton Escort Fighter + 8x 20 ton Boxes = 676 tons of hull metal

• 262,580,800 / 676 = Cr388,434 per ton construction cost in volume production

So the "larger, more (drive) powerful" version is costing ~Cr50,000 more per ton ... but what you GET for that added expense is +1 parsec range and +1G acceleration.
That sounds like a pretty worthwhile investment.

The other thing that I'm noticing is that on the economic spreadsheet of operator break even point to profit analysis, the main driver of operator expenses under subsidy is actually crew salaries and annual overhaul maintenance expenses. However, these two variants (410 ton and 500 ton) have extremely similar crew salary costs:

• 7 crew, 3 troops (410 tons) = Cr34,600 per 4 weeks
• 8 crew, 2 troops (500 tons) = Cr38,860 per 4 weeks

Point being that under subsidy, the minimum revenues needed to break even will rise slightly ... but the maximum profit potential will rise dramatically. Basically, the minimum revenue needed to break even rises slightly, but the maximum profit potential rises dramatically ... so there is a "magnification effect" on both ends of the revenue generation spectrum, but that magnification is asymmetric in a way that actually favors the larger, more (drive) powerful 500 ton J3/3G Clipper design as being a more "efficient" way to generate returns on investment.

It's not just a matter of "we make it up in volume" with respect to the way the 500 ton design stacks up against the 410 ton design ... but that's definitely part of it.

Spinward Flow said:

Maybe the J3/3G Clipper isn't "dead" as a design option after all ... it's just restin' ...

Click to expand...

CHIRP

Been re-examining my choices for Escort Fighter.

16 ton small craft hull, configuration: 1
5 tons for LBB2.81 standard A/A drives (codes: 6/C, TL=9, Agility=6, EP=2)
1 ton fuel
4 tons bridge
4 tons model/3 computer (EP: 1)
1 ton mixed triple turret (missile/sandcaster/missile, TL=10)
* 184 tons external docking (180/1.1=167 tons capacity)
2 tons small craft stateroom
= 5+1+4+3+1+2 = 16 tons

Single production (100%) cost: MCr35.288
Volume production (80%) cost: MCr28.2304


I'm now putting these 16 ton Escort Fighters into a 20 ton hangar berth meant for the 20 ton Boxes for reasons of maximum commonality in form factor.

Spinward Flow said:

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

Click to expand...

The advantage of this 16 ton with model/3 computer design balance point is that it is CHEAP for the capabilities (it's approximately the same price as a Type-S Scout/Courier!). However, it IS only occupying 16 of the 20 tons of berthing space available to it, leaving 4 tons of "wasted space" that could be put to better use.



But ...
If I were to "bulk things up" to make the installation of a model/4 computer possible, I would need to increase the (LBB2.81) standard power plant from A to B (increasing output from 2 EP up to 4 EP) and would have an upper limit on small craft tonnage of 20 tons displacement that would still need to fit into the 7.5x5.5 deck squares form factor of the 20 ton Boxes.



20 ton small craft hull, configuration: 1
8 tons for LBB2.81 standard A/B drives (codes: 6/L, TL=10, Agility=6, EP=4)
1 ton fuel
4 tons bridge
4 tons model/4 computer (EP: 2)
1 ton mixed triple turret (missile/sandcaster/missile, TL=10)
* 180 tons external docking (180/1.1=163 tons capacity)
2 tons small craft stateroom
= 8+1+4+4+1+2 = 20 tons

Single production (100%) cost: MCr55.76
Volume production (80%) cost: MCr44.608

Definitely a LOT more expensive, but that's only to be expected when you need to increase both your installed power plant (+MCr8) AND computer capabilities (+MCr12).

MCr35.288 / 16 = MCr2.2055 per ton of displacement
MCr 55.76 / 20 = MCr2.788 per ton of displacement

Ah, but what would such a beast look like if it were drawn up into deck plans?



And here's the proof that it would fit within the 7.5x5.5 deck squares form factor of the 20 ton Boxes:



And for anyone who claims that the "deck plan shapes" when drawn onto a 2D grid "don't look like a Needle/Wedge configuration" ... ask yourself what this "triple needle hull(s)" configuration spacecraft would look like when drawn on a 2D grid of deck squares:



Funny thing is, to my eyes, those "double spike ram fuel scoops" on the front of the port/starboard "power nacelles" give the deck plan a sort of "castle merlons" aesthetic look to the deck plan. I also tried to minimize the line of sight conflict(s) to visibility from the crew workstations inside the bridge. The fuel scoop fin structures protrude slightly into the lateral view, but not so much as to be a hindrance to (visual) situational awareness for the pilot and gunner.



So even though it's more expensive to build, the 20 ton Light Fighter has advantages due to its more powerful computer (model/4 instead of model/3) ... which improves both offense AND defense simultaneously (computers are SO IMPORTANT for combatants in LBB5.80!). Additionally, the larger power power plant would mean that the fighter would retain more Agility at when externally loaded, due to having a 0.8 EP reserve capacity when not encumbered by external loads.



And that just means that I've given myself yet another reason to favor the 500 ton J3/3G SIE Clipper design over the 410 ton J2/2G SIE Long Trader design.

Spinward Flow said:

Spinward Flow said:

Maybe the J3/3G Clipper isn't "dead" as a design option after all ... it's just restin' ...

Click to expand...

CHIRP

Click to expand...

Chirp indeed ...

Huh.
That's an interesting result for the 500 ton J3/3G SIE Clipper (re)design.

Note that the design features 9x 20 ton hangar bays which can optionally be filled with (9x 20 tons of collapsible fuel tankage) if the Escort Fighter and/or Boxes are moved from the interior hangar bays out to external docking points on the exterior of the starship's hull.

---

J1+1
1600 - 500 = 1100 / 1.1 = 1000 ≈ 1000 tons of external load capacity for small craft tonnage
(50*20) = 1000 tons of small/big craft tonnage
1. 500+(50*20)*1.1 = 1600 ≈ 1600 tons @ J1 = 160 tons jump fuel
2. 500+(42*20)*1.1 = 1424 ≈ 1424 tons @ J1 = 142.4 tons jump fuel
(160)+142.4=302.4 tons total jump fuel
180+(160)-302.4=37.6 tons fuel available for power plant during voyage

---

J1+1+1+1+1+1
1600 - 500 = 1100 / 1.1 = 1000 ≈ 1000 tons of external load capacity for small craft tonnage
1000-500 = 500 tons of small/big craft tonnage remaining when "buddying towing" an inactive 500 ton starship of the same class
(25*20) = 500 tons of small/big craft tonnage
1. 500+(500+25*20)*1.1 = 1600 ≈ 1600 tons @ J1 = 160 tons jump fuel
2. 500+(500+17*20)*1.1 = 1424 ≈ 1424 tons @ J1 = 142.4 tons jump fuel
3. 500+(500+10*20)*1.1 = 1270 ≈ 1270 tons @ J1 = 127 tons jump fuel
4. 500+(500+7*20)*1.1 = 1204 ≈ 1204 tons @ J1 = 120.4 tons jump fuel
5. 500+(500+7*20)*1.1 = 1204 ≈ 1204 tons @ J1 = 120.4 tons jump fuel
160+142.4=(302.4)+127=(429.4)+120.4=549.8+120.4=670.2 tons total jump fuel
180+(180) + 180+(180) - 670.2=49.8 tons fuel available for power plant during voyage

---

J1+1+2
800 - 500 = 300 / 1.1 = 272.7272 ≈ 272 tons of external load capacity for small craft tonnage
(13*20) = 260 tons of small craft tonnage
1. 500+(22*20)*1.1 = 984 ≈ 984 tons @ J1 = 98.4 tons jump fuel
2. 500+(17*20)*1.1 = 874 ≈ 874 tons @ J1 = 87.4 tons jump fuel
3. 500+(13*20)*1.1 = 786 ≈ 786 tons @ J2 = 157.2 tons jump fuel
98.4+87.4=(185.8)+157.2=343 tons total jump fuel
180+(180)-343=17 tons fuel available for power plant during voyage

---

J2+2
800 - 500 = 300 / 1.1 = 272.7272 ≈ 272 tons of external load capacity for small craft tonnage
(13*20) = 260 tons of small craft tonnage
1. 500+(13*20)*1.1 = 786 ≈ 786 tons @ J2 = 157.2 tons jump fuel
2. 500+(6*20)*1.1 = 632 ≈ 632 tons @ J2 = 126.4 tons jump fuel
(157.2)+126.4=283.6 tons total jump fuel
180+(140)-283.6=36.4 tons fuel available for power plant during voyage

---

J2+3
533 - 500 = 33 / 1.1 = 30 ≈ 30 tons of external load capacity for small craft tonnage
(1*20) = 20 tons of small craft tonnage
1. 500+(6*20)*1.1 = 632 ≈ 632 tons @ J2 = 126.4 tons jump fuel
2. 500+(1*20)*1.1 = 522 ≈ 522 tons @ J3 = 156.6 tons jump fuel
(126.4)+156.6=283 tons total jump fuel
180+(120)-283=17 tons fuel available for power plant during voyage

---

There are almost certainly additional permutations possible, but I wanted to see what "maximum range demand" would look like (for undamaged starships).

The big surprise was that J1+1+1+1+1=5 parsecs result when "buddy towing" an inactive starship of the class ... so that a client can take delivery in a star system other than where construction was completed (basically, "ship a copy" of the class "as cargo" to a destination). In the "buddy towing" configuration, the internal fuel tanks (180 tons) and collapsible fuel tanks (180 tons) of BOTH ships are available to supply jump fuel for the transit (while the starships are docked together, of course). This winds up yielding a combined unrefueled range of 5J1 ... which has interesting implications for a shipyard "as out of the way" as Grote/Glisten/Spinward Marches is, if you can offer "delivery" of completed starships to clients who do not want to travel.



However, at a chartered external load cargo ticket price of Cr900 per ton per jump ... @ 500 tons of starship plus another 180 tons of Escort Fighter and Boxes ... that starts adding up in a hurry:

1. (500+180)=680*900 = MCr0.612
2. (500+20)=520*900 = MCr0.468
3. (500+0)=500*900 = MCr0.45
4. (500+0)=500*900 = MCr0.45
5. (500+0)=500*900 = MCr0.45

0.612+0.468+0.45+0.45+0.45 = MCr2.43 to "5J1 external cargo delivery" a copy of the starship class (and its sub-craft) to a client 5 parsecs distant from the shipyard.

Considering that the 80% cost volume production construction cost for the 500 ton J3/3G SIE Clipper currently stands at MCr278.9584 ... a 20% down payment on a starship plus all sub-craft would set a buyer back MCr55.79168. Adding the cost of an "unrefueled 5J1 external cargo delivery" to a client on top of the down payment price represents a +4.355% surcharge over and above the funding needed for a down payment.

So for a price of MCr58.22168, a buyer can afford a down payment AND get a finished starship "delivered direct, no refueling needed along the way" to any star system 5 parsecs distant from the shipyard (~6 weeks after construction finishes). The "delivery" starship could then refuel and simply J2+3 "return to home port" back at the shipyard.

Of course, clients who would rather pick up their purchases upon completion at the shipyard are welcome to do so, although it is recommended that clients taking this option should bring their crew with them to staff their new purchase immediately. Clients who want their crew(s) to be plankowners are encouraged to arrive at the shipyard in advance of shipyard completion of their order(s) so as to participate in familiarization training during final fitting and shakedown testing.