Building a flying city

[PsiTraveller]

I've been thinking of the flying city of Drinax Castle.

What rules would you use to have a city capable of floating above a world? m-Drives with backups, but what other rules would you use for power needs and cost of construction? Has anyone played around with building flying/floating real estate?

 

[cunningrat]

I would say don't re-invent the wheel. The Floating City is essentially a space station with somewhat smaller life-support requirements: just use the space station rules to build it, with perhaps a huge discount for Hull to represent it being open.

That does bring up an interesting question, though. Where does the Floating City get fuel for its M-drives?

 

[DarkDawning]

It would depend on how fast you want it to move. A cloud city that mostly floats around you could treat as a giant air raft using antigrav. I suspect that would save a lot of energy

 

[paltrysum]

The Vehicle Handbook combined with the Space Station rules from High Guard might be able to manage this, but a vehicle of that size might challenge the Handbook's scale. Haven't tried it yet, but might be worth a look.

 

[Condottiere]

I've thought about the floating cities in context of High Guard engineering.

The most likely solution they came up with probably would be, assuming Terran standard gravity minus (technological level ten) or Terran standard gravity plus (technological level eleven), would be advanced technology manoeuvre drive one or one plus respectively, tweaked orbital range, and likely seventy five percent energy efficient.

Unless you can accumulate five disadvantages, in which case technological level twelve and thirteen, respectively, in which case, probably twenty percent smaller.

Complete with complementary technological level nine 0.25% volume early fusion, with advanced technological variant at thirty percent thirty percent size reduction at technological level eleven, standard fusion at twelve, standard advanced technological variant at thirty percent thirty percent size reduction at technological level fifteen.

Control booth likely space station variant.

 

[PsiTraveller]

Not a lot of fuel needed when you think about it. Let's say 100 000 tons of Floating city. Assume Thrust 1 to make the math simple, if it is less than that (space stations use thrust 0, but we want the city to be able to move around the world, so Thrust 1)

Thrust 1 for 100 000 tons is 1 percent of volume or 1000 tons of M Drives.
Power needs is 10 000 Points (100 000 tons at 10 percent times Thrust 1 is 10 000 points of power)
Assume the city is like a ship for 20 000 points of power per month. (20 percent is basic ship needs).

So you need 30 000 points of power production
TL 12 is 15 points per ton, so 2000 tons of power plant.

Fuel needed per month is 10 percent of that, so 200 tons of fuel for 4 weeks of flying around.

Page 54 of Highguard allows for M Drives to be 0.25% of volume for Thrust 0 station keeping. We want the mobility, but Thrust 1 allows for orbital lift in just over 30 minutes, so that might be a little ambitious. Even cutting the M-Drive tonnage in half and keeping the power output saves a lot of space and money, but the power needs are the same. (10 000 points is the pg 54 M Drive needs listed, 10 percent of hull tonnage)

So 2000 tons of plant and 200 tons a month in fuel, and it can be unrefined fuel so not that expensive.

 

[AnotherDilbert]

So 2000 tons of plant and 200 tons a month in fuel, and it can be unrefined fuel so not that expensive.

Quite, and refill continuously at a rate of less than 10 Dt per day. A smallcraft dipping a local ocean will suffice.

 

[PsiTraveller]

Oooh, put an 11 ton tank in and then assure the customer that just in time delivery is always dependable. Nothing bad ever happens. :shock:

 

[AndrewW]

Oooh, put an 11 ton tank in and then assure the customer that just in time delivery is always dependable. Nothing bad ever happens. :shock:

Until hackers put ransomeware on that small craft and you can't operate it.

 

[Condottiere]

There's always solar panelling.

 

[PsiTraveller]

Not to be argumentative but would solar panels work in a vehicle (city) that is floating? Or would that qualify as minimal movement only and not operating at full thrust? I like the idea of a city surrounded by a fan of panels powering it as it floats serenely above the landscape, but the rules on pg 36 might get in the way.

On the other hand, an orbital array with panels and a power relay to the city might be able to solve that problem.

For that matter a space based solar power system might be considered the first thing a colony should get to provide power for a growing world.

 

[DarkDawning]

Not to be argumentative but would solar panels work in a vehicle (city) that is floating? Or would that qualify as minimal movement only and not operating at full thrust? I like the idea of a city surrounded by a fan of panels powering it as it floats serenely above the landscape, but the rules on pg 36 might get in the way.

On the other hand, an orbital array with panels and a power relay to the city might be able to solve that problem.

For that matter a space based solar power system might be considered the first thing a colony should get to provide power for a growing world.

i can see the on the first sunset,, does it feel like we're dropping lower to you

 

[Condottiere]

Fleeing twilight.

Or chasing dawn.

Or just parking over the Poles.

 

[Tea Rex]

Flying cities are so cool and obviously it is not so difficult to build one at the TL predominant in the imperium, as I have learned here.

Great, there will definitely by at least one flying city (also) in my campaign!
And yes, Condottiere, why not the "Everlasting Dawn"?

 

[Condottiere]

 

[Reynard]

Every world with at least one flying city reevaluates when the first flying city plummets killing. most inhabitants. There is nothing so immensely fragile.

What were we thinking?!

 

[Tea Rex]

What were we thinking?!

Because we can!
(a very human attitude that is quite common )

 

[Condottiere]

 

[PsiTraveller]

My name is Ozymandias, King of Kings;
Look on my Works, ye Mighty, and despair!


Ego and an expression of power may be a reason.
Or on planets with bad conditions on the planet, tidally locked according to the random seed I got on Travellermap.com. This is not mentioned in the Trojan Reach book.