Ship Design Philosophy

Discuss the Traveller RPG and its many settings
baithammer
Lesser Spotted Mongoose
Posts: 724
Joined: Wed May 31, 2017 2:21 am

Re: Ship Design Philosophy

Postby baithammer » Sat Mar 10, 2018 4:10 am

AnotherDilbert wrote:
Sat Mar 10, 2018 2:44 am
No:
HG, p24 wrote:Up to three weapons may be mounted on a fixed mount...
Ugh, keep crossing up firmpoints / hardpoints.
Condottiere
Chief Mongoose
Posts: 6521
Joined: Mon Sep 23, 2013 8:23 pm

Re: Ship Design Philosophy

Postby Condottiere » Sat Mar 10, 2018 12:07 pm

It's strange, despite the new template, I have trouble keeping track of stuff as well.
Condottiere
Chief Mongoose
Posts: 6521
Joined: Mon Sep 23, 2013 8:23 pm

Re: Ship Design Philosophy

Postby Condottiere » Sat Mar 10, 2018 10:56 pm

Spaceships: Tail landers

https://www.youtube.com/watch?v=T3_Voh7NgDE

How To Do A Hoverslam - Things Kerbal Space Program Doesn't Teach.

If you're landing a rocket then waiting to the last minute slamming on the brakes actually saves fuel over slower, more considered approaches to landing.



Gravitic motors don't need to be economical, but commercial ships seem to like factor ones, so microfactor rockets to give an additional boost during take off and landing, maybe.
baithammer
Lesser Spotted Mongoose
Posts: 724
Joined: Wed May 31, 2017 2:21 am

Re: Ship Design Philosophy

Postby baithammer » Sun Mar 11, 2018 12:00 am

Condottiere wrote:
Sat Mar 10, 2018 12:07 pm
It's strange, despite the new template, I have trouble keeping track of stuff as well.
Mostly too much fluffy bits in with the mechanics, could be fixed with giving the fluff first then providing a clear mechanics only block at the end.
Condottiere
Chief Mongoose
Posts: 6521
Joined: Mon Sep 23, 2013 8:23 pm

Re: Ship Design Philosophy

Postby Condottiere » Tue Mar 13, 2018 8:57 am

Starships: Virtual Crewing and Bridge Optional

Parsecage varies, but let's take the esample of a two hundred tonne starship:

Ten tonne bridge costs one million schmuckers, and need at least a factor one computer worth thirty kay schmuckers.

The virtual crew replaced would be:

. Captain - autonomous programme
. Pilot
. Astrogator
. Sensor Operator - translating exterior sensor information for the Captain, Pilot and Astrogator
. Engineer
. Steward
. Mechanic
. Internal Security Officer

You'd need a factor two computer to simultaneously run a jump programme factor one and a five man virtual crew, which of course can exchange the subprogrammes depending on the operation the starship is carrying out.

The minimal programme per five somewhat competent crew members is a megacredit. The immediate capital layout difference is a hundred and thirty thousand schmuckers deficit, versus salaries, a superfluous ten tonne bridge volume, crew staterooms, crew escape capsules.
AnotherDilbert
Cosmic Mongoose
Posts: 3237
Joined: Wed Dec 23, 2015 2:49 pm
Location: Sweden

Re: Ship Design Philosophy

Postby AnotherDilbert » Tue Mar 13, 2018 10:18 am

HG, p64 wrote:Virtual Crew can replace up to five pilots, gunners or sensor operators on board a ship ...
No Astrogators, Engineers, or Stewards replaced. You might use Expert software (and a bigger computer) for that.

Also note that Virtual Crew has no hands and can't polish drives or serve drinks. You might allow Expert software to control Repair Drones for Engineers and Mechanics, otherwise you need robots. Replacing Stewards probably needs robots.
SSWarlock
Greater Spotted Mongoose
Posts: 1039
Joined: Wed Jun 27, 2007 3:26 pm
Location: Fulacin/Rhylanor/Spinward Marches

Re: Ship Design Philosophy

Postby SSWarlock » Tue Mar 13, 2018 7:03 pm

AnotherDilbert wrote:
Tue Mar 13, 2018 10:18 am
Also note that Virtual Crew has no hands and can't polish drives or serve drinks.
And it can't fight boarders.
Sir Dhaven Hevelin, IOD, Baronet of Fulacin
Owner/Captain - S.S. Warlock

Playing Traveller/RQ/D&D since 1977
baithammer
Lesser Spotted Mongoose
Posts: 724
Joined: Wed May 31, 2017 2:21 am

Re: Ship Design Philosophy

Postby baithammer » Tue Mar 13, 2018 10:59 pm

The gunner part is a bit silly as the virtual gunners are a better deal.
AnotherDilbert
Cosmic Mongoose
Posts: 3237
Joined: Wed Dec 23, 2015 2:49 pm
Location: Sweden

Re: Ship Design Philosophy

Postby AnotherDilbert » Wed Mar 14, 2018 12:06 am

Virtual Crew is very good for a fighter or small ship. Virtual Gunner is a better deal for larger ships. Both are good value, in different cases.
Condottiere
Chief Mongoose
Posts: 6521
Joined: Mon Sep 23, 2013 8:23 pm

Re: Ship Design Philosophy

Postby Condottiere » Wed Mar 14, 2018 3:08 am

Repurpose and reprogramme repair drones.

Image
Condottiere
Chief Mongoose
Posts: 6521
Joined: Mon Sep 23, 2013 8:23 pm

Re: Ship Design Philosophy

Postby Condottiere » Fri Mar 16, 2018 1:22 am

Spaceships: Hull Configuration and Streamlining

Why is a tear drop shape more aerodynamic with a round head, than with a sharp head (as if mirroring the back end)?
6 Answers
Suryanarayanan R
Suryanarayanan R, Amateur Aero-Engineer
Answered Mar 26 2015 · Upvoted by Achilleas Vortselas, Ph.D. Mechanical Engineer · Author has 154 answers and 130.6k answer views
The tear drop is somewhat the most aerodynamic (i.e. has least drag) under the assumption of a subsonic flow of moderately high Reynold's number (say Re ~ 10^4) on an axisymmetric body.

Overall, The following affect the drag on an axisymmetric body under these assumptions :
Pressure distribution over the surface of the body,
The skin friction, and
The location of flow separation.

The obvious answer to your question is that, the pressure distribution and the skin friction on the sharp head is such that it's drag coefficient is higher as compared to the one with a relatively blunt head.

The Drag Coefficient for a Half Cone (with the sharp edge pointing forward) is 0.50 while that of a Half Sphere with the same frontal area is 0.42.

Source : Drag coefficient

On thinking this through, I surmise that at the front end, we would like to minimize skin friction drag, hence keep a lower length for the flow to pass through - but not completely a vertical flat plate(in which case the Drag Coefficient = 1)!
At the rear end, we would want to avoid flow separation for as far as possible and avoid the turbulent wake, as this will monumentally increase drag.
7.7k Views · View Upvoters
Your response is private.
Is this answer still relevant and up to date?
Yes
No
Promoted by SimScale
How CFD helps in air conditioning studies for office designs.
Join this webinar on how to use cloud-based CFD to study AC designs for thermal comfort in office spaces.
Sign up at simscale.com
Related QuestionsMore Answers Below

Why is a bell shape more aerodynamic than a sphere shape?
What is the most aerodynamic shape?
Aerodynamics: If it is a 50 mph wind and you drive your car at 50mph downwind, if you stick your head outside would you feel the wind?
What is the best aerodynamic shape for car models?
Why do F1 cars have aerodynamic shape?
Ask New Question
John Palmore
John Palmore, PhD student in Aerospace Engineering
Answered Mar 26 2015 · Author has 105 answers and 72.9k answer views
Separation.

Airfoils are designed in the way that they are designed so that the air going over them will not separate. This is important because the separation will cause a type of drag force to appear. This will make your airplane less efficient, because it will have to overcome more force to fly. The configuration that you give will certainly separate at the rear.

I found a video on YouTube of a triangular wedge by Andreas Muller. It shows the problem of separation it quite well. A vortex forms behind the triangle which indicates separation. In the frame I grabbed, the center of the vortex is marked by a horizontal red line.


That vortex means separation. Separation means more drag. While the case you're describing is a bit different from what's in the video, the same phenomenon will result. The flow will separate near the rear end of the airfoil, and drag will ensue.

Here's the full video.

4.1k Views · View Upvoters
Your response is private.
Is this answer still relevant and up to date?
Yes
No
Dave Robinson
Dave Robinson, More than 1/4 of a century working in Aerospace Design for some of the world's top Aerospace companies
Answered Mar 27 2015 · Upvoted by Achilleas Vortselas, Ph.D. Mechanical Engineer · Author has 587 answers and 839.8k answer views
Thank you for the A2A opportunity.

It isn't exactly the case. Aerofoil shapes tuned to provide Lift tend to have a rounded (radius) nose in order to enhance the stall characteristics of the Aerofoil. It should be noted that aerofoils tuned for supersonic flow past them tend to have fairly sharp leading edges.

However, if the aerofoil's principle purpose is to reduce Drag and not generate Lift then a slender symmetrical shape (about its centre) may very well produce the least aerodynamic Drag; by maintaining Laminar flow past the surfaces of the body for subsonic velocities.

In most applications, some sort of structural strength is required at the leading edge of an aerodynamic shape and this necessitates some thickness in order to provide volume in which to fit the structure.

* A fineness ratio, between 4 and 12, typically applies to the cylindrical shaped fuselage of a commercial transport aircraft and indicates the lowest Drag configuration. It represents the ratio of fuselage length and its average diameter.
3.4k Views · View Upvoters · Answer requested by Ciprian Blu
Your response is private.
Is this answer still relevant and up to date?
Yes
No
Thomas Moura
Thomas Moura, M.S. Mechanical Engineering & Aerospace and Aeronautical Engineering, University of Campinas (2015)
Answered May 27 2017 · Author has 333 answers and 48.5k answer views
This shape is only the best for lowish speeds, for transonic and supersonic the best shape is called sears-haack body. At low speeds, the shape of a tear minimizes the detachment of the flow, that would generate drag due to turbulence. This flow detachment is caused by an condition called “adverse pressure gradient” where the local pressure of the flow is increasing in the direction of the of the flow in essence “braking” it up to the point the flow separates.

So this is the shape that minimizes this adverse pressure gradient.
608 Views · View Upvoters · Answer requested by Sanjeev Sai
Sai Kiran
Sai Kiran, Aeronautical engineer, Lateral thinker & a lifelong learner
Answered Mar 31 2015 · Author has 289 answers and 120.7k answer views
For easy understanding: A tear drop is symmetrical in shape, imagine a fish in water, it can swim easily due to its nature of streamline as its shape can allow it to pass through water easily. Similarly imagine you are holding a cardboard and you have dipped in water in such a way that, when you move cardboard in water the flow acts on the surface, while moving you feel resistance which is the drag(in simple words force which prevents movement) created by water.
The drop can't be as streamline as a fish because of drag produced by air, the leading part of drop bulges but maintains its symmetric nature.
2.3k Views
Ramesh Agarwal
Ramesh Agarwal
Answered Mar 8 2017
I won’t be able to give you the scientific proof but I’ll present an example. The secret is in the name itself. Which shape does a tear or a rain drop assume when falling down?

That’s right the tear drop shape; hence its name.

Why that’s the most aerodynamic? Well suppose you’re going on a motorcycle, obviously you would bend to decrease your drag. Similarly the drop tries to reduce the drag and thus becomes the tear drop shape which we all know so well.

Of course there are other things related to the water droplet such as the surface tension and the viscous force but this is the simplest answer which I can write.



Teardrop - sphere or streamlined?
Condottiere
Chief Mongoose
Posts: 6521
Joined: Mon Sep 23, 2013 8:23 pm

Re: Ship Design Philosophy

Postby Condottiere » Sun Mar 18, 2018 1:54 pm

Starships: Virtual Crewing and Bridge Optional

One issue with virtual gunners for large ships is bandwidth, or lack thereof.

For a warship, you'll have a lot of applications competing for limited resources, which is why you'd need crew personnel, or autonomous robots.

Image
Condottiere
Chief Mongoose
Posts: 6521
Joined: Mon Sep 23, 2013 8:23 pm

Re: Ship Design Philosophy

Postby Condottiere » Sun Mar 18, 2018 10:06 pm

Spaceship: Stables, Manger, Cargo Bay, and Accommodations

In theory, a cargo bay costs nothing, but I assume that stables provide some rudimentary indoor plumbing for water, air, climate control and waste removal.

A stable tonne is also fifty times cheaper than a stated one.

You could probably squeeze in more than two people per four and a half square metres, though installing two or three storey pull down slabs in a bunk bed arrangement will cost extra.

If you take the default two people per tonne, and balance it off with a tonne of biosphere, you forego that two thousand schmuckers of life support costs, and half extra space to move about. It will cost you two hundred kiloschmuckers and an energy point, which you'll make up in sixteen years and eight months, actually longer if you include the power plant, but you get to grow your own tomatoes.
AndrewW
Cosmic Mongoose
Posts: 4163
Joined: Fri Dec 19, 2008 11:57 pm

Re: Ship Design Philosophy

Postby AndrewW » Sun Mar 18, 2018 10:09 pm

Condottiere wrote:
Sun Mar 18, 2018 10:06 pm
If you take the default two people per tonne, and balance it off with a tonne of biosphere, you forego that two thousand schmuckers of life support costs, and half extra space to move about. It will cost you two hundred kiloschmuckers and an energy point, which you'll make up in sixteen years and eight months, actually longer if you include the power plant, but you get to grow your own tomatoes.
You also forgo the cargo space to put in a biosphere.
Condottiere
Chief Mongoose
Posts: 6521
Joined: Mon Sep 23, 2013 8:23 pm

Re: Ship Design Philosophy

Postby Condottiere » Sun Mar 18, 2018 10:31 pm

Opportunity cost.

Actually, I think it's nine years and two months, which includes yearly maintenance costs. Plus two years at minimum for the budgeted early fusion power plant, though you could power it off solar panels.
baithammer
Lesser Spotted Mongoose
Posts: 724
Joined: Wed May 31, 2017 2:21 am

Re: Ship Design Philosophy

Postby baithammer » Mon Mar 19, 2018 1:52 am

Condottiere wrote:
Sun Mar 18, 2018 1:54 pm
Starships: Virtual Crewing and Bridge Optional

One issue with virtual gunners for large ships is bandwidth, or lack thereof.

For a warship, you'll have a lot of applications competing for limited resources, which is why you'd need crew personnel, or autonomous robots.

Image
Under the Tigress there is this note about over provisioning programs.
Note all the software can’t run at it’s full
rating together. What is running at any
given time is determined by the needs of
the ships crew at the time. A full crew is
carried but virtual software may by used if
necessary due to loses.
Further..
A Traveller can use any high-Bandwidth software at a lower Bandwidth, to a minimum of the lowest Bandwidth
shown. For example, a Traveller could run Intrusion/3 on a Computer/1, but it would only function as Intrusion/1.
Basically, you only run programs at full bandwidth when required and when a different set of programs are required you downgrade the original set and put the required ones up to full bandwidth usage.
Condottiere
Chief Mongoose
Posts: 6521
Joined: Mon Sep 23, 2013 8:23 pm

Re: Ship Design Philosophy

Postby Condottiere » Tue Mar 20, 2018 2:44 am

I'm aware of the mix and match.

But you'd want targetting acquisition and electronic countermeasures at maximum, and the Tigress has a potential five thousand weapon stations.
baithammer
Lesser Spotted Mongoose
Posts: 724
Joined: Wed May 31, 2017 2:21 am

Re: Ship Design Philosophy

Postby baithammer » Tue Mar 20, 2018 3:50 am

A lot of the weapons would've been better as bays or larger bays and would reduce the weapon crew required.

As for targeting, only a limited number of targets would be required to be engaged as the number of systems would generally be used in battery not as individual systems.
Condottiere
Chief Mongoose
Posts: 6521
Joined: Mon Sep 23, 2013 8:23 pm

Re: Ship Design Philosophy

Postby Condottiere » Wed Mar 21, 2018 4:45 am

Image

I'd automate the spinal mount, but the crew ranges from twenty eight to eight hundred seventy five, not counting supervision; what you'd save on health insurance and disability should more than make up for it.

But viably, I'd say the computer caps out at five hundred, and I can't recall autoloaders being mentioned in High Guard.
Condottiere
Chief Mongoose
Posts: 6521
Joined: Mon Sep 23, 2013 8:23 pm

Re: Ship Design Philosophy

Postby Condottiere » Fri Mar 23, 2018 8:23 pm

Spaceships: Armaments, Missile Weapons System, and Launch Tubes

Launching and recovering smaller craft from a larger ship is usually a time-consuming activity when using docking spaces or full hangars. Launch tubes allow craft to be launched rapidly, using electromagnetic technology similar to that used by railguns. Multiple launch tubes are often installed on capital ships that carry small craft, allowing them to launch potentially entire squadrons very quickly.

It takes one round to manoeuvre a craft into ‘firing’ position within a launch tube but, once there, it takes a single combat round to release up to ten craft it into space or an atmosphere and both the mothership and smaller craft may expend thrust and make attack rolls during this round.

A launch tube consumes an amount of tonnage equal to ten times the size of the largest craft it must launch. In addition, each craft carried on the ship that will use the launch tube must have a docking space or full hangar (using the costs and tonnage on page forty five).

A launch tube costs a semimegacredit and requires one scott per tonne.


That would be:

. sand canister - half a tonne

. missile - five sixths of a tonne

. torpedo - three and one third of a tonne.

Who is online

Users browsing this forum: No registered users and 19 guests