Pondering starship evolution

[Condottiere]

Furniture can be (re)assembled.

 

[whartung]

The plans are looking great @Spinward Flow

 

[kilemall]

In your modular paradigm perhaps , but that is a lotta airlock- which is LEGO flexibility and safety, but also a lotta failure point.

I’m thinking more trad deck plans and a differentiation between specs for services.

Re door thickness, to me the armor 40 is either external hull, airlock as you have it or the ACS bulkhead between engineering and the deck as in the Snapshot plans.

So something more like armor 20 for the interior- big reason why redoing the interior is cheaper and more doable. Also, decided as a result of rumination on this that the ACS bulkhead is not just safety firewall but actually load bearing which is why you can’t retrofit bigger drives in re TCS.

 

[Spinward Flow]

that is a lotta airlock- which is LEGO flexibility and safety, but also a lotta failure point.

It is a lot of airlocks ... but it's also a redundancy ("you can have either zero or two!"). That way, if one of the decontamination airlocks "stops working" (for whatever reason), you haven't lost your one and only decontamination airlock.

Re door thickness, to me the armor 40 is either external hull, airlock as you have it or the ACS bulkhead between engineering and the deck as in the Snapshot plans.

The way that deck plans are drawn in the LBBs, there's 2 types of walls ... Bulkheads and Partitions.
Bulkheads require 1000 points of damage to break through.
Partitions require 100 points of damage to break through.

For my purposes (in making deck plans), the main difference is pressure barriers.
Bulkheads are required to enclose a pressure sealed space.
Partitions are NOT strong enough to maintain a pressure seal for interior spaces.
So bulkheads will stop decompression, but partitions will not.

Also, decided as a result of rumination on this that the ACS bulkhead is not just safety firewall but actually load bearing

Very much so. Bulkheads are both pressure barriers AND load bearing structures.
In fact, if you look at the deck plans drawn in LBB S7 and other LBBs, it quickly becomes apparent that bulkheads are used for the outer hull line silhouette and also around interior deck spaces surrounded by fuel tanks (the Type-S and Type-J being the most obvious demonstration of this). When you have large interior areas organized into "blocks" inside the hull, you only need the bulkheads around the pressurized individual sections on each deck, with all of the other space divisions being made up of partition walls.

To my knowledge, bulkheads usually get hatches, iris valves (including grav lifts) and maintenance hatches as access points through bulkheads. By contrast, partitions seem to be limited to sliding doors and maintenance hatches. All airlocks involve enclosing the airlock space with bulkheads. The Express Boat is modestly unique in that the class has redundant airlocks (1 iris valves, 1 hatches) built into the design (LBB S7, p9), in addition to maintenance hatches in the engineering compartment (which are not airlocked to exterior access).



Although it may not look like it at first glance, I do actually use partition walls and (unpressurized) sliding doors in the Stateroom Boxes. The partition wall and sliding door separate the fresher areas from the rest of the single occupancy stateroom spaces in both versions of the Stateroom Boxes (holo lounge/galley/laundromat and autodoc infirmary). The reason why there are so many bulkheads everywhere is to prevent a breach in one area of a 12 ton module from propagating throughout in the Stateroom and Laboratory modules. The use of bulkheads for the central access corridor walls and pressure doors to enter the rooms on either side is what makes it possible to use the corridor space as airlocks to cycle pressure through for entry and egress. Same deal with the Grav Lift in the center for vertical access.

 

[Grav_Moped]

Pivot door.

You can't move large equipment through it, but the crew can squeeze past them.

Pivot, then slide the door sideways to one side or the other.

 

[Condottiere]

You want that fixed in place, so that any boarders in armour have to blast the door off the pivot, in order to pass through.

 

[Grav_Moped]

You want that fixed in place, so that any boarders in armour have to blast the door off the pivot, in order to pass through.

That would make it not particularly useful as a door, unless it was double-width.

I'm seeing it as a type of door that could be opened despite differential pressurization. Once the air gets out (and it works in both directions), the door is slid sideways out of the way on its hinges/pivot bearings.

This is distinct from, for example, doors in jet aircraft that open inward and are held closed by cabin pressure. (Except when the entire door assembly blows out because someone forgot to bolt it back in place after maintenance.)

 

[Spinward Flow]

I'm seeing it as a type of door that could be opened despite differential pressurization.

Um ... doors are NOT supposed to open when there is a pressure differential .

If there's a pressure differential (pick your threshold) ... either the door WON'T open (automatically) or the door CAN'T open (manual bute force).

Once the air gets out (and it works in both directions), the door is slid sideways out of the way on its hinges/pivot bearings.

So ... once the pressure differential is gone ... the door can be opened.

 

[Grav_Moped]

So ... once the pressure differential is gone ... the door can be opened

Actually, opening the (pivot) door lets the air out.

Not great for external doors, but for internal hatches where either side of the door could be depressurized, and where getting through the door regardless is a design priority, it's not terrible.

 

[Dragoner]

You can open doors in a spacecraft against pressurization, aircraft are a bit different because of wind speed.

 

[Condottiere]

The idea for a pivoting door in the corridor was because it's balanced and swingable; I don't think air pressure is a factor, because the volume in the room wouldn't change as you swing it.

Iris valve shouldn't have an issue with air pressure, but the pivot door can be opened manually.

 

[Spinward Flow]

Iris valve shouldn't have an issue with air pressure

LBB S7, p6-7:

lris Valves: lris valves are pressure-tight automatic portals set in bulkheads.
lris valves close automatically when a pressure difference is sensed between the two sides of the bulkhead. They will not close fully until the valve is clear of any foreign objects (like legs, hands, etc).

 

[Condottiere]

As noted in the description, the artificial limitation is sensor based, and pretty much safety orientated.

Other than that, there would be nothing to prevent them from opening or closing, if there are pressure differences.

 

[Spinward Flow]

You can open doors in a spacecraft against pressurization, aircraft are a bit different because of wind speed.

Can you?
Really?

Let's just assume the typical standard American door dimensions ... 80 inches high x 30 inches wide = 2400 inches².
Even at a mere 10lbs/inch² of pressure differential on an aperture of that size, you're looking at 24,000lbs (12 short tons!) of pressure force being exerted on a door of that size/area.

 

[Dragoner]

IIRC it is something like 6-8 tons, though you are only moving a fraction of that, and air maximum speed of movement is at speed of sound.

 

[whartung]

You can open doors in a spacecraft against pressurization, aircraft are a bit different because of wind speed.

Tell that to the Apollo 1 crew. Pressurization from the fire was one of the compounding problems that led to them having difficulty opening the hatch, and why future hatches opened outward.

 

[Dragoner]

Tell that to the Apollo 1 crew. Pressurization from the fire was one of the compounding problems that led to them having difficulty opening the hatch, and why future hatches opened outward.

They died in 12 seconds, and the fire had raised the pressure to 29 psi, it also ruptured the command module's inner wall. Gas expands under heat, and fire.

Apollo 1 - Wikipedia

en.wikipedia.org

 

[Spinward Flow]

Made some more headway on my SIE Big Clipper "upsizing" design of deck plan layouts informed by finally getting the various loadout configurations settled and sorted. There's actually a pretty long list of options available (more than I was expecting, actually):

1. J3
2. J2
3. J2
4. J1
5. J1
6. J2+3
7. J2+2
8. J1+1

Not bad for a J3/3G "baseline" trim that can be loaded up with additional 12 ton boxes and/or 140 ton pods for external towing (at the expense of drive performance, temporarily). Decided to do a "vertical stacked layers on top of each other" view for each of the options to give a sense of how they would all look when moving boxes and pods around to exterior docking points.

The main external hull docking points for load towing are:

1. Dorsal Over Port Wing
2. Ventral Under Port Wing
3. Ventral Centerline Under Fuselage
4. Ventral Under Starboard Wing
5. Dorsal Over Starboard Wing

Although the baseline design does not incorporate L-Hyd Drop Tanks as a standard feature (because, TL=10 starship design using LBB5.80 but with LBB2.81 standard drives and turret weaponry), I've deliberately left enough wing area outboard towards the wingtips in the deck plans where conformal L-Hyd Drop Tanks (4x 30 tons or 6x 20 tons) could be retrofitted as an aftermarket option (over/under the wings) without conflicting with the typical dorsal/ventral, port/starboard wing docking points used by external loads.



I posted this back in post #86 of this thread, but it's still pretty enough that I think it deserves a repeat as I prepare for final proofreading passes through the offline doc files I've been using to organize all of this effort through.

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I figured out how to use the Travellermap Poster Maker Jump Map function to create an image for me that I could then modify using my updated world iconography color scheme (with better/thicker ring colors) to make a beautiful tramp merchant portolan chart jump map for District 268 and the relevant neighboring subsectors.

Yes, those thicker rings on the world icons make them visually easier to read at a glance.

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Although the Regina subsector was the "original frontier" for CT (thanks to LBB A1, et al.), I've come to appreciate the thought that the Five Sisters, District 268 and Glisten subsectors actually make for a better "fringes of civilization" region to be playing around in as a tramp trader (either free or subsidized) wanting to "go beyond the border" and Live An Interesting Life™ while aspiring to become a Merchant Prince (or just an adventuring Traveller).

The region is a challenging one to navigate ... even if most of the worlds in the above image lie along the Spinward Main ... simply because type A/B starports are in the superminority (20 out of 64 star systems shown above), with many of the type A/B starports clustered together with longer stretches of type C-X starports in between, making for potentially hazardous voyages. At the same time, there are numerous Non-industrial trade coded worlds in this region of space, many of which are actually Low Population (4-) with a limited demand for interstellar transport services, creating challenges for merchant ships with extremely large passenger and/or cargo capacities who may not be able to fill up their shipping manifests reliably, creating balance sheet problems.

In short, it's a "tough neighborhood" out in District 268 (so you'd best be prepared to defend yourself!)... but at the same time, there are a LOT of disparate trade codes scattered around, meaning that there are (speculative goods) OPPORTUNITIES to be had for the taking ... if you've got the Right Crew and the Right Ship to marry up those supply and demand opportunties.

 

[Spinward Flow]

A little bit more tinkering around the edges with the SIE Big Clipper and I've reverted back to a standard crew of 7, rather than trying to reach for 6 ... which means accommodations for only 5 high passengers instead of 6. This does impact the revenue potential of the ship's economics when balancing out for profit margins (+Cr475 per month in crew salaries, -Cr10,000 per destination in passenger ticket revenue maximum) ... but the change makes it easier to find and recruit crew when each crewman only needs a single department skill, rather than trying to combine skills from different departments into a single crewman role aboard.

So although it's possible and permitted (under RAW) to do things like require Pilot-3/Gunnery-2 in a single crewman, for example ... the pool of candidates possessing such skill combinations is going to be vanishingly small (I've checked the LBBs for skill result combos and this specific mix is HIGHLY unlikely, even if theoretically possible). By contrast, hiring two crewmen with Ship's Boat-1 and Gunnery-1 skills respectively, is going to be a LOT easier to do and be open to a much wider pool of potential applicants.

So, back to the 7 crew and 5 high passengers "standard" loadout we go ...

 

[Grav_Moped]

Although the Regina subsector was the "original frontier" for CT (thanks to LBB A1, et al.), I've come to appreciate the thought that the Five Sisters, District 268 and Glisten subsectors actually make for a better "fringes of civilization" region to be playing around in as a tramp trader (either free or subsidized) wanting to "go beyond the border" and Live An Interesting Life™ while aspiring to become a Merchant Prince (or just an adventuring Traveller).

Yeah. Regina is "at the edge" but is only the edge. The wilds are beyond there... (and are Vargr space, if you like that kind of thing...)
D268 and 5-Sis are actually "beyond the edge" but are still Human Space,

I'm deliberately ignoring the issues with Egryn and Pax Rulin (they shouldn't be as unknown as Leviathan makes them out to be...)