I.S.A. STANDARD CRUISER

Just after the Drakh attack on Earth the other races do indeed, as Mr. Michael Garibaldi said, "go nuts when they find out" about the new 'Whitestar Class Destroyer'. So Johnny Nuke'em throws the dogs a bone.

He tells them, "We had to build them because we needed bigger ships to support the Whitestars. We still do. But with the drydocks destroyed it won't be for more than three years until we get any new destroyers. In the mean time we could use some cruisers to fill the gap."
Cruisers, being smaller, could be built faster.
"If one of you (the other races) would agree to build some more ships for us we could help out with some tech."

The details of the plan are for the Minbari to work with each race to design and build a prototype for testing. The Minbari won't supply any more tech until the contest is over, but they will ensure the design fits the ISA design pattern and is flexible enough that the new systems can be fitted in after. The winner, best ship/best price, will get the tech and the contract to build more cruisers.
Earth, by way of its colonies, will supply compatible subsystems like turrets (from their experience working on the WCD). these types of things can be built faster than the ships they are put into so it won't slow down Earth's efforts to rebuild its fleet

By way of the plan;
The Rangers get new ships.
The winning race gets more tech.
The losing races still get help making the tech they got when they joined the ISA work better with their own.
And Earth ensures that more ships are out there looking for a cure.

The basic hull is 1,500m long with three 750m tall fins on the back, racked rearward and tapering a little towards the tips (housing the Narns first generation gravitetic drive system). The front and back parts of the hull are triangular sectioned tubes housing the trio of G'quan engines in the rear (along with the main fuel tank and reactor) and a trio of the G'quan's heavy beam weapons in the front. These two parts will be joined by 500m long pressurized cylinder for the crew. (it is a little narrower than the two end sections)
While the engines are arranged in the standard 12-4-8 o'clock positions the beams are placed in the 2-6-10 o'clock positions. The 9 anti-fighter turreted guns are placed on the crew cylinder, three near the weapons head in the 2-6-10 o'clock positions, three in the center in the 12-4-8 o'clock positions and three near the engine block in the 2-6-10 o'clock positions. On each side face of the weapons head is placed a medium pulse gun turret to ward off ships of Drakh raider sized class. Plus three more of these guarding the back (one on the tip of each fin, Sho'Kar style), actually the fins have a sensor pod running along the edge of their tips and the gun turret sits on this. The turrets on the main hull are placed on short pedestals (5m high) to allow the proper working of the new defensive system
The interceptors are placed in a 'turret on a turret' configuration. These small turrets sits, one each, on the 15 other weapons turrets.
The fighter bays are a line of 10 hatches on the underside of the crew cylinder. (as Narns don't know which fighter the ISA uses the hatches should be wide enough for Starfuries and long enough for Nials). The fighters are racked and launched like bombs are dropped from a WW2 British bomber.
A cruiser sized ship also needs ship to ship/station/planet transportation for its crew so an 11th larger bay is placed amidships, just under the middle anti-fighter turret group, between the 5th and 6th figther bays
On each side of the crew cylinder is placed a line of escape pods for a crew of 150, 5 on each side.
Even without gravitetic drive the ship, with the full thrust of a Q'Guan Heavy Cruiser, had 4 times the acceleration due to it being 1/4 the mass. And this acceleration proved to be a 'force multiplier' in offensive and defensive tactics. In fact when the speed was combined with the heavy weapons load the Human adage - "The best defense is a good offence" was proven. With the limited amount of armor that could be placed on a ship of this type playing a secondary role in the survival of the ship the Narns started to re-think the design.

Could they make it even faster? The G'Quan engines were already putting out as much thrust as they could. The gravitetic drives could only be used in a turn because at full thrust the G'Quan engines consumed all the power the reactors could spare. Only when an engine on the inside of a turn was throttled down could a gravitetic fin be powered up on the outside of a turn. If they wanted to run both systems at full thrust at the same time they would need to find more power from their fusion reactors. A switch to matter/anti-matter reactors could do it but there are drawbacks to using anti-matter.
Although anti-matter provides more power than fusion most races prefer to use fusion because of refueling concerns. Anti-matter is a 'secondary fuel'. It must be produced in large centralized facilities at great cost in energy. Fusion fuels on the other hand can be mined in any star system. And hyperspace access can put any ship within only a few hours of the nearest star system.
The Narns have decided to stay with their fusion reactors for most of the power needs of the ship but include a small anti-matter fuel supply for 'peak power demands'.

Once this had been worked out the next step to making this light cruiser faster lay in making it lighter. The Narns have traditionally used thick sections of titanium in their ship's hulls because of the large reserves of this element on their homeworld but as this would be an ISA ship they could plan on other materials coming in from other worlds in the ISA. Additionally there were 'active' armor systems to consider. In fact the Humans had already agreed to the use of their Mk II defense grid in the ship with 15 turret on turret interceptors along the hull and 3 more interceptors co-axial to the main beam weapons. (in disregard of the benefits of this ship being 'out there' searching for a cure Earth Force could not justify sharing their Mk III defense grid technology and even withheld the 'energy web' part of the system)

The hull itself was given a two zoned approach to armoring. Areas where the crew would be got the full protection of a spaced triple hull while the fins, engine core and main beam housing only has a single 10cm hull. The triple hull of the crew cylinder comprises of a 10cm inner hull separated from a 25mm middle hull by 1m deep I beams acting as stringers and longitudinal framers with another set of 1m deep I beams acting as stringers and longitudinal framers separating the 10cm outer hull from the middle hull. The webbing of the I beams have large cut-outs so cryogenic gases can be circulated through the hull spacing as an active cooling system. Liquid helium3 was chosen as the coolant so that it could double as a backup fuel supply.

In addition to being a triple hull design the crew cylinder uses a multi-layered 'sandwich' construction to maximize protection and conserve material mass. The outer hull is made up of 3 layers, 2 layers of metal-matrix titanium on either side of a granular iron composite.
In metal-matrix composites Titanium (Ti), Aluminium (Al), copper (Cu), and magnesium (Mg) alloys can be combined with silicon carbide (SiC), alumina (Al2O3), boron carbide (B4C), and other particulate, fiber, or whisker reinforcements to significantly increase stiffness or improve the thermophysical properties of components.
Because the outer hull would have to resist the highest temperatures continuous silicon carbide fiber was chosen to reinforce the titanium alloy. (also because silicon is a common element on terrestrial planets like Narn, an important consideration after two periods of Centauri stripmining) With the mix having a fiber content of 40% there was also a large reduction in the mass of titanium which was not as plentiful as it once was.
The granular iron composite was a 'gift' of the Centauri orbital bombardment. The fallout of dust from the nickel/iron asteroids was 'farmed' out of the soil with magnets and bonded together in a thermoplastic base. An energy beam passing through this will encounter multiple interfaces between high Z (iron) and low Z (plastic) material with a small degree of refraction compounded at each interface, tripping the parallel particles into an 'inverse square rule' spread pattern. For best results this layer is the thickest. Some might consider this 'plastic steel' composite a 'poor man's plasteel' as its production costs are only a fraction of the costs of the EF's 'plasma formed steel' however its energy refraction performance is still 3/4 of the VCD's hull. (meaning it refracts 60% of any energy weapon that hits it)

The middle hull and the I beam spacers are all made from a beryllium matrix with boron carbide (B4C) particulate. Although this material had to be imported it was considered worth the added cost. (Narn security guards on Babylon 5 have reported the anti PPG effects of beryllium when used in airlocks) It's known to have a stiffness/weight ratio 6X steel and conducts heat so well it has a specific heat 4X titanium. Its used as a heat sink for the outer hull and increases the transfer of heat to the circulating helium3. The boron carbide particulate was added not only to increase its compressive strength but also the boron10 that has been used is 10X as effective as lead in stopping neutrons. Lead is also used in the hull. A layer of foamed lead/tantalum carbide cermet insulates the inner hull from the cryogenic temperatures of the helium3.

For its part the inner hull is also a metal matrix composite. Aluminium, on average makes up 8% of a terrestrial planet's crust, Narn is no different. After two periods of Centauri stripmining the Narns could no longer afford to overlook this resource. The Narns haven't used it up until now because aluminium has poor fatigue resistance and titanium has better higher temperature strength. The Humans and Minbari provided the means correct these weaknesses. Scandium (Sc) is a rare earth element that, when alloyed with aluminium in small amounts, can - increase its tensile strength 20%, triple its fatigue resistance and recrystalize its grain structure so it can be 'coldworked' and welded like steel. Kilo for kilo Scandium/Aluminium is 50% stronger than titanium at low and mid temperatures and low/mid temperatures are the norm at the inner hull. The Sc aluminium has been re-enforced by another form of aluminium - single crystal Al2O3. (sapphire whiskers) These have a record tensile strength of 42.7 GPa. They are difficult to manufacture in long fiber form so instead the Narns have asked the Minbari to nano-engineer the cheaper short whiskers with nobs on their ends so they can not pull free of the matrix and spurs along their sides so they interlock. The Minbari agreed to supply the whiskers, but only for the production models

Gravitetic Defense Fields
When entry into the ISA allowed the Narns to trade for Gravtech they thought of using anti-gravity fields to repel enemy weapons fire. However they also knew of the problems the Centauri had with this idea. First generation gravity field generators are just not strong enough to divert or stop high speed particle streams.
It took a little bit of *thinking outside the box* but the Narns did find a way of using gravity fields for protection, attractive gravity fields. Their new idea was to use gravity to hold something on to the hull that would block enemy weapons fire. Something loose and fluid that would flow into the contact point of enemy weapons fire to replenish itself where/when it was needed. They have called this idea

The Fluid Defense System
Knowing such a system would also block fire from their own weapons they designed the system to hold the fluid within 5m of the hull and put the turrets on 5m high pedestals. They also knew the fluid would need to be stored inside the ship when not in use so they have chosen a gas that can be compressed and liquefied for storage and expended into a dense/cold gas outside. Xenon was found to have the properties they needed. It was heavier than air so the gravity fields would hold it closer to the hull and it could be lightly ionized so standard Narn electromagnetic defense fields could help hold it closer. Thick clouds of particulate matter could be add to this atmosphere to fine tune the blocking effect. (and because the type of particulate could be changed on demand it was adaptable) The ionizing effect of some enemy weapons fire would be handled by xenon's property of glowing (a nice blue color) when energized and re-radiating the energy back into space. The thermal effects were to be handled by the near cryogenic temperatures of the gas and the physical impact effects would be handled by dispersing the energy throughout the external atmosphere in wave action. The system is not completely effective but it does reduce the energy of enemy weapons fire as it passes through the atmosphere.

E.F.N.I. (In fact, the siteowner) Gives his sincere thanks to the Technomage Galen, that provided either the beautyful article and the concept that was at the origin of this drawing -

TECHNICAL SPECIFICATIONS
Class: Standard Cruiser
Type: Patrol/Assault
Lenght: 1500 meters
Mass: CLASSIFIED
Acceleration: CLASSIFIED.
Crew: 150
Troops: CLASSIFIED
Fighters: 10 multipurpose launching bays.

Power/Propulsion:
3*E-15 G'Quan Fusion Reactors.
1*NGI 1000 Gravitic matter/antimatter Reactor.
1*INM-1 Gravitic Drive.
3*K-15 G'Quan ion engines.
3*NGI-15 G'Quan Jump engines.


Weapons:
3*GN-155 G'Quan laser/particle beam cannons.
6*NGI/Westinghouse Twin Medium Pulse cannon turrets
15*Walther-Raytheon WRNE1105 Interceptor/Light Pulse Cannon Turrets.


Defense:
See Description above.

I.S.A. STANDARD CRUISER