Ship Design Philosophy

[ProfGrizzlyJon]

What exactly does per Thrust mean? Per g of thrust?

That was the way that I read it. The intent was to use .1G, based on the rest of the context about primitive spacecraft in that Supplement.

 

[Condottiere]

Upto this point (in time), plasma drive is the most efficient (direct) converter of fuel into thrust, by electrifying it, in Traveller.

But even two and a half times efficiency still ensures it's a gas guzzler, which the stereotype of ye turboprop somewhat contradicts, for a regional airliner, or military transporter.

Also, it takes up a larger percentage of the spacecraft.

Now, reactionary rocket powered spacecraft tend to work out for intraplanetary, orbital, and lunar, transportation, since there is sufficient gas in the tank, and the cost of that is balanced by lower maintenance ones, and capital outlay.

Being within or near orbit, doesn't really make chucking out atomic warheads out the rear cargo hatch, to act as propulsion, appealing to the local electorate.

And, I suspect, atomic warheads aren't cheap.

Lightships might qualify, on the basis that if powered by an active fusion reactor, it's use it or lose it; but, I don't think it's been given the Mongoose treatment.

 

[Condottiere]

And speaking of orbital activities.

At some point or another, you would generally come to the conclusion that, in the long run, a gravitationally based manoeuvre drive is the most pragmatic, and that means overall cost of ownership.

Without one, you have to install heat shielding for your spacecraft, to effect atmospheric reentry, and those things aren't cheap, if you compare prices, followed by overall practicality.

Hundred tonne spacecraft, heat shielded, zero tonnes, plus ten megastarbux to the bill of materials.

Hundred tonne spacecraft, factor/one manoeuvre drive, default, one tonne at two megastarbux, and ten power points (early fusion one tonne reactor, half a megastarbux); two tonnes, two and half megastarbux.

 

[Sigtrygg]

Upto this point (in time), plasma drive is the most efficient (direct) converter of fuel into thrust, by electrifying it, in Traveller.

There is more to it than just fuel to thrust.

A plasma drive has to include the power plant and power plant fuel that is required, as well as the fuel it uses for reaction mass.

A standard reaction engine plus "fuel" with no power plant requirement actually uses less tonnage over all than a plasma drive plus power plant plus fuel.

At TL8
plasma drive 20% of hull per thrust, for a 100t ship that's 20t
each ton requires 1 power point so for a 100t ship that's 20 EPs, which requires an additional 2 tons of fission power plant and 1 ton of power plant fuel
fuel is 1% (of hull?) per thrust per hour, so for the 1 hour that's 1t of fuel. Total 24 tons.

For a 100t ship, a 2t reaction drive requires only 2t of fuel for 1 hour. Total 4 tons

 

[ProfGrizzlyJon]

Upto this point (in time), plasma drive is the most efficient (direct) converter of fuel into thrust, by electrifying it, in Traveller.

But even two and a half times efficiency still ensures it's a gas guzzler, which the stereotype of ye turboprop somewhat contradicts, for a regional airliner, or military transporter.

Also, it takes up a larger percentage of the spacecraft.

Now, reactionary rocket powered spacecraft tend to work out for intraplanetary, orbital, and lunar, transportation, since there is sufficient gas in the tank, and the cost of that is balanced by lower maintenance ones, and capital outlay.

Being within or near orbit, doesn't really make chucking out atomic warheads out the rear cargo hatch, to act as propulsion, appealing to the local electorate.

And, I suspect, atomic warheads aren't cheap.

Lightships might qualify, on the basis that if powered by an active fusion reactor, it's use it or lose it; but, I don't think it's been given the Mongoose treatment.

You should be able to refine the detonators from liquid hydrogen fuel.

 

[ProfGrizzlyJon]

There is more to it than just fuel to thrust.

A plasma drive has to include the power plant and power plant fuel that is required, as well as the fuel it uses for reaction mass.

A standard reaction engine plus "fuel" with no power plant requirement actually uses less tonnage over all than a plasma drive plus power plant plus fuel.

At TL8
plasma drive 20% of hull per thrust, for a 100t ship that's 20t
each ton requires 1 power point so for a 100t ship that's 20 EPs, which requires an additional 2 tons of fission power plant and 1 ton of power plant fuel
fuel is 1% (of hull?) per thrust per hour, so for the 1 hour that's 1t of fuel. Total 24 tons.

For a 100t ship, a 2t reaction drive requires only 2t of fuel for 1 hour. Total 4 tons

Not a valid representation for sustained use.
<21 hours total acceleration/deceleration is where they balance out. Plasma becomes more efficient afterwards.

By comparison, with fuel for only 20 hours of 1G thrust, split into 10 hours of acceleration and 10 hours of deceleration, you can travel from Earth to Mars at closest approach (55 million km) in approximately 2.2 days (53.3 hours)

Alternatively, you only need 3.5 hrs of 1G thrust to travel between Earth orbit and Lunar orbit.

 

[Sigtrygg]

By which time 40% plus of your ship is drives and fuel. Not much chance of building a 2g plasma drive ship is there.

Where the plasma drive would be useful is is using fractional g thrust for long duration. A 0.5g plasma drive is going to achive parity with a reaction engine at a lower tonnage, so of you stick with that 40% payload being drives and fuel you would get the drive down to 10t, the power plant and fuel down to 2 t so 12t with 36 hours of 0.5g thrust available. But MgT doesn't like playing with less thrust than 1g...

 

[ProfGrizzlyJon]

By which time 40% plus of your ship is drives and fuel. Not much chance of building a 2g plasma drive ship is there.

Same problem as jump drives; plasma drives have the chance for reduced size and reduced fuel as they progress.

.5G still gets you between the Earth and the Moon in 5 hrs (with accel-flip-decel)

 

[Condottiere]

First, you look at the options available.

Then, you figure out their pros and cons, especially in relation to your needs.

Finally, figure out if you can tweak them to more conform with said needs.

If you assume you will have to undertake atmospheric reentry, your path divides to either gravitational derived drive, and/or heat shielding.

You could, of course, acquire a subsidiary spacecraft for that role.

You end up trying to balance availability, acceleration, range, endurance, cost, power, and volume.

In the long run, in terms of endurance, the plasma drive beats the reactionary rockets, but requires tens times more volume.

 

[Condottiere]

Spacecraft: Accommodations and Airlines SABOTAGED Themselves?!

Today we’re looking at the technical side of these seats, and why they can be such a headache. Because especially NOW, seats have become one of the airline industry’s single biggest bottlenecks in getting airplanes into the sky!

0:00 - Intro
4:56 - Who Makes Airplane Seats?
10:55 - Custom Airplane Seats
15:31 - How Long Does It Take to Make Airplane Seats?

I guess that deckchair isn't going to cut it, anymore.

 

[Condottiere]

Spacecraft: Armaments, Virtual Weapon Systems, and Fixed Mountings

1. I tend to think that design concepts have to be viewed in terms of plausibility and competitiveness.

2. Plausibility in view of the setting something is taking place.

3. Competitiveness in regard to keeping everything on a level playing field.

4. Up to three weapons may be mounted on a fixed mount (small craft have additional limitations), while turrets can mount one, two or three weapons, depending on their type.

5. Mount TL Power Tons Cost
..... Fixed . — . 0 . 0 . MCr0.1

6. I mean, if I installed a derringer in the spacecraft, I'd have to allocate tonnage.

7. Weapons of up to 250 kilograms may be mounted on spacecraft using 0.25 tons per weapon.

8. As such, for default turret weapon systems, each instance should require a volume allocation of a quarter of a tonne.

9. Missile racks still retain their mystique.

 

[ProfGrizzlyJon]

Spacecraft: Armaments, Virtual Weapon Systems, and Fixed Mountings

1. I tend to think that design concepts have to be viewed in terms of plausibility and competitiveness.

2. Plausibility in view of the setting something is taking place.

3. Competitiveness in regard to keeping everything on a level playing field.

4. Up to three weapons may be mounted on a fixed mount (small craft have additional limitations), while turrets can mount one, two or three weapons, depending on their type.

5. Mount TL Power Tons Cost
..... Fixed . — . 0 . 0 . MCr0.1

6. I mean, if I installed a derringer in the spacecraft, I'd have to allocate tonnage.

7. Weapons of up to 250 kilograms may be mounted on spacecraft using 0.25 tons per weapon.

8. As such, for default turret weapon systems, each instance should require a volume allocation of a quarter of a tonne.

9. Missile racks still retain their mystique.

Agreed.
It gets even more silly when you have groundscale weapons that are greater than 1 ton and cannot fit in a turret.

Which is why I do it….

 

[Condottiere]

In theory, you should be able to customize the size of your turret, to fit in whatever systems, weapons or otherwise, you want, within reason.

Or, stuff it into a barbette, if agreement can't be found.

Costs are completely made up, so I rarely argue over them, except whether they seem too cheap or expensive, especially in comparison with other similar items in Traveller, or actual ones.

But, volume is rather scientific, and should be (ac)countable.

 

[ProfGrizzlyJon]

In theory, you should be able to customize the size of your turret, to fit in whatever systems, weapons or otherwise, you want, within reason.

Or, stuff it into a barbette, if agreement can't be found.

Costs are completely made up, so I rarely argue over them, except whether they seem too cheap or expensive, especially in comparison with other similar items in Traveller, or actual ones.

But, volume is rather scientific, and should be (ac)countable.

As I understand it, the High Guard options are <.25dt, it can be a "free" (no power, no displacement) pop-up turret or a fixed mount. Larger weapons, but <1dt, it can be added to a turret or a fixed mount, displacing a minimum of 1dt, but still using no power. It is implied that any weapon >1dt cannot be mounted to a turret.

However, if you use Vehicle Handbook option, you can have fixed mounts, pintle/ring mounts, gun ports, bays, external hardpoints (no relation to the HG hardpoint or firmpoint), small turrets (equivalent to the HG groundscale turret), large turrets (can accept any size weapon). These can further be made into pop-up mounts and modular mounts.

 

[Condottiere]

I always thought it might just be easier to use Vehicles chassis as weapon platforms, and either park them in the cargo hold and drop the hatch to let them fire out of that, or place them into docking clamps, actual volume being tonnage.

The question of power requirement, I can't really answer, since outside some rather vague requirements about what type of power plant a chassis needed, no exact details for the energy weapon systems is mentioned.

The problem, if you can call it that, for fixed mounts is that like a spinal mount, it takes manoeuvring to place it in line with the target; exception missiles and torpedoes.

Even setting up a machine gun at the airlock requires volume, but even in pop up mode, not necessarily a quarter tonne.

Gun ports are actually fixed mounts, though for that Age of Sail aesthetic, make them pop up.

A lot of possibilities would be non canonical, so that needs to be clearly marked.

You should be able to convert a hardpoint into three firm points, and split that into two mounted fixtures and a single turret, but since energy weapon systems are then capped at close range, you have to come up with a weapon system selection that would make that worthwhile; advantage would be that by splitting it up, you can fire the firmpointed single turret and the fixed mountings separately.

 

[ProfGrizzlyJon]

I always thought it might just be easier to use Vehicles chassis as weapon platforms, and either park them in the cargo hold and drop the hatch to let them fire out of that, or place them into docking clamps, actual volume being tonnage.

The question of power requirement, I can't really answer, since outside some rather vague requirements about what type of power plant a chassis needed, no exact details for the energy weapon systems is mentioned.

The problem, if you can call it that, for fixed mounts is that like a spinal mount, it takes manoeuvring to place it in line with the target; exception missiles and torpedoes.

Even setting up a machine gun at the airlock requires volume, but even in pop up mode, not necessarily a quarter tonne.

Gun ports are actually fixed mounts, though for that Age of Sail aesthetic, make them pop up.

A lot of possibilities would be non canonical, so that needs to be clearly marked.

You should be able to convert a hardpoint into three firm points, and split that into two mounted fixtures and a single turret, but since energy weapon systems are then capped at close range, you have to come up with a weapon system selection that would make that worthwhile; advantage would be that by splitting it up, you can fire the firmpointed single turret and the fixed mountings separately.

I have a set of permutations about this that I dubbed "softpoints" and use IMTU. Basically, this limits them (groundscale weapons) to dogfight engagements, if you intend to use them against other spacecraft (page 162 of Core22) or vehicles (page 138 of Core22).

 

[Condottiere]

Don't term them softpoints; you'll want something to emphasize reinforcement.

We do have grapples, torpedo or otherwise, plus launcher containers.

In theory, external pylons for weapon stores, but that's very non canonical for spacecraft.

 

[ProfGrizzlyJon]

Don't term them softpoints; you'll want something to emphasize reinforcement.

We do have grapples, torpedo or otherwise, plus launcher containers.

In theory, external pylons for weapon stores, but that's very non canonical for spacecraft.

Softpoints is the logical regression from hardpoints to firmpoints. That is also used as a brand name by the manufacturer.

Grapples and container launchers are described as external pylons.

 

[Condottiere]

Be(ar) soft on your hull.

Bear down hard on your target.

 

[Condottiere]

Inspiration: Military Sci-Fi Audiobook | Marines in Galactic Battlefront

Slow starter.

Gets more Travellerish a little later.

Possibly, a cunning tonguist.