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Use of collapsible tanks exposed...

S

ScryingEye

SOC-2
Want to design a modular system for fuel tanks based off of T1's TCS.

Can anyone see problems using modular collapsible fuel tanks exposed on the outside of a carrier or tanker? Obviously, no armor, but what about during jump and such?
 
Collapsible Tanks within Classic Traveller refers to fuel bladders within an enclosed environment, typically a cargo hold.

The nearest in CT you have to a collapsable tank for the exterior is drop tanks, which have a cost and present logistics challenges to replace.

If you chose to use exterior fuel bladders in your TU, you may need to ponder on the nature of jump space and what constitutes a "hull", for example are your collapsible bladders as protected as the ship hull.

You might be considering an exterior bladder that empties prior to jump and is then pulled inside the ships hull for jump. Might be doable, but its not mentioned in cannon and again for your TU you need to consider whether you get enough time to package your bladder before your ship has to expend the energy accumulated while emptying it.

If experimenting with non-cannon jump fuelling methods, also consider the Fuel Tanker at 100D, that just passes you a very large diameter hose. You get charged for the cost of fuel plus a new hose and suck down what you need to jump (the hose suffering damage during the jump).

Personally I don't use any of these options. Not for any good physical reason, but because such devices change the nature of space travel and cheapens commerce in Traveller to the point the rest of the Traveller background is chronically strained. My argument (not that I feel I need one, nor will I defend it) is that if it were possible in Traveller, MM would have included it in canon. In addition, if it were possible, everyone would be doing it resulting in no real change (economically and militarily the balance would be the same), excepting I would have to rewrite large parts of the background. (For example the Tigress would be some 200000 tons lighter and cost say 60% of the price indicated, the 200tn tramp Steamer would weigh only 180 ton and cost say 90% of the price indicated).

All food for thought
Matt
 
This does bring up the question of disposable lightweight droptanks that have to be used during jump.
 
I'm specifically looking for non-military application, to be used in civilized areas only.

Not to be used as internal fuel, but for transport as cargo. Transport jumps in with full tanks, jump out with emptied tanks that had been bundled up. Treat either as "modular" or as external items carried in docking clamps.
 
ScryingEye said:
I'm specifically looking for non-military application, to be used in civilized areas only.

Not to be used as internal fuel, but for transport as cargo. Transport jumps in with full tanks, jump out with emptied tanks that had been bundled up. Treat either as "modular" or as external items carried in docking clamps.
Click to expand...

I'm curious, usually the only reason for carrying excess fuel is for strategic reasons rather than economic. Its got to be a pretty dry system to make importing hydrogen/water from neighbouring systems worthwhile.

But going with the flow; perhaps at the system with the hydrogen/water, build a surplus of modular tanks. Make trips to the dry system, leaving the modular tanks with a local firm to break down to flat packs for return. Think today's shipping containers, some of which break down to flat packs for shipping empty.
 
The real issue is jump capability. The engines on a ship are generally built for the volume of the ship, without any extra capacity. If you put the bladders on the outside of the ship, then you have a different ship than the jump drive was built for. (It is possible to build in for a larger volume, but it would have to be purpose-built, imo.)

Plus, what everyone else has written. :D
 
Fritz_Brown said:
The real issue is jump capability. The engines on a ship are generally built for the volume of the ship, without any extra capacity. If you put the bladders on the outside of the ship, then you have a different ship than the jump drive was built for. (It is possible to build in for a larger volume, but it would have to be purpose-built, imo.)

Plus, what everyone else has written. :D
Click to expand...

MongTrav has Docking Clamps, so we have the math for that. I'm looking at the problem of using collapsible external. Would the collapsible tanks be safe enough for jump? (Think of the current for expanding station component (LINK) being tested by NASA. By TL 10, why not be able to make it contract just as easy?)

Yes, this would most likely be a custom built ship, or an existing hauler pulling tanks.

And yes, the area is bone dry but economically worthwhile, requiring fuel to be imported.

I would say that by TL15 this would be safe to use collapsible tanks externally, but what about TL 10 to 13?
 
One thing I see clear is those collapsible tanks would sure make the ship unstreamlined if not already so, and they could only be refilled in space (not even skimming gas as partial streamlining would allow), as they are described as fuel bladders.

IIRC something like this (external fuel bladders) were used by an Ucranian frigate class in 2300AD.
 
According to the rules, fuel in collapsible tanks cannot be used directly for jump. It has to be transferred to the regular tanks first. Internal or external, collapsible tanks won't work. All they are good for is carrying extra fuel.


Hans
 
You simply have a significant integrity issue securing dTons worth of L-Hyd. Maybe it could be done with a net made from aircraft cable around the bladder.

But, regardless of how it's done, in the end, you have a Volume X+External Bladder size ship, and you need a Jump drive capable of driving it.

The premise of a drop tank is to fuel the ship prior to jump so that they can be jettisoned and your 1KdTon ship remains a 1KdTon ship, but arrives filled with jump fuel since it was consumed from the drop tank.

Bringing the fuel with you doesn't save you anything, save, perhaps, less fuel for the jump back (since you are now "smaller").

If you're in this dry system for the short term, you may as well use a commodity ship and jump 1/2 as far. If you're there for the long term, consider hunting down some ICEsteroids and setting up a processing facility. You need a cheap source of water there anyway just to support the endeavor in the system.

So, seems to me, I'd just use regular ship for this endeavor rather than building a new one from scratch.
 
I see two proposals here:

1) Rigid structure that telescopes out to provide increased internal volume, providing mechanical support and g compsentation (if installed) for the fuel bladder. Simular in concept to the extensible walkways used by airports to get passengers to the aircraft cabin door, expect some 30% of the non extended volume to be consumed by the walls for the extensible section, and machinery to control the exact amount of extension, vaccuum seals and the like.

2.) Non-rigid external fuel bladders, occupying 10% volume when not filled. (Exposed to vaccuum and hazards of space.)

Jump Grid ships, no to either method.
Hull plate ships ,yes to #1: deploy extra hull plates to cover the new surface area, slight engineering challenges there, but do-able. no to #2.
Jump bubble ships esp irregular or distributed configurations, piece o cake, either method can be employed.

Restrictions: (lower tech levels)

type 2 external fuel bladders:
Reduced maneuverability: The external bladders are away from the area of effect of g compsention modules and are not stressed for large (any) g forces. (Think of how carefully you have to throw a water ballon of only a hundred cm3 throw too hard and the thing ruptures as you try to accelerate it.)

Chance of hitting the jump field: Attitude changes or accelerations while in jump may cause the bladder envelope to distend enough to touch the edge of the jump field. With the loss of containment, the fuel in that bladder will be lost.

Hull streamlining is reduced to none with the installation of the bladders.

Chance of micro meteroid damage inflicting some losses of fuel.

Ship jump performance must be recalculated for every different configuration of full and empty (partial full too) external bladders.

More space effecient than the extensible hull section more easilly lost/damaged, more restrictions.

Type 1 extensible hull sections:

Streamlining: lower the hull's streamlining one class from Airframe to (simi)-streamlined, or from (simi)-streamlined to none when extended (See rules on pop up turrets.)

Vaccuum seals for the extensible section are less robust, and it is very difficult to engineer them to resist negative pressure. (under water, aerodynamic pressure while gas giant scooping or in atmospheric flight) This may be negated by having the extensible section withdraw fully into the hull and close the large cargo hatch it is extended out of.
 
We might have to come up with some rules for both the reconfigurable hull design and the collapsible tanks. Had the idea for an expandable hull design earlier but warwizard's suggestion consolidated it. This combined with the collapsible tanks should do what we want.

Thanks, everyone.
 
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