Vehicle Building Issues

[Sigtrygg]

Where do you get the idea that grav tanks hug the ground?

Tech level 12: All vehicles have sufficient free-flight performane that ground combat
vehicles effectively no longer exist, having merged with aircraft. The primary weapon of the
heavy gunships include plasma B guns, VRF gauss guns, and tac missiles.

Tech level 15: Gunships mounting rapid pulse X guns and heavier Z guns are virtually indistinguishable
from orbital craft.

 

[Shardan13]

See Condottiere's comment above. It is not that they can't, it's they shouldn't or else they become a very clear target to their enemy.

 

[Condottiere]

I'd go with there being several different techniques that gravitational motors employ to achieve flight.

At the lowest level, what you create is a hover effect, and maybe one or two hundred klix per hour.

You are going to have to assume that weight plays a critical role in whether the gravitational motor can lift the craft off the ground, and speed, but not necessarily the altitude, which would be inhibited by some other aspect of the engine/physics.

 

[Shardan13]

An argument that can be made that grav tanks are ground hugging is that grav tanks weak point is their floor. It and the top armor are the thinnest and unlike the top is undefended by weapons. So anyone attacking a grav tank will aim at its floor. The attacked grav tank facing many types of military grav vehicles will seek to be below them so its turret weapon can aim up. The lowest both attackers can get is ground hugging height.

As an aside this suggests that a grav tank with bottom armor as thick as its front armor may have an advantage over those that don't.

 

[Condottiere]

The reason the bottom armour tends to be less is a matter of compromise, in terms of weight and cost.

Land mines and improvised explosive devices, which are opportunistic.

Missiles are hunter killers.

 

[Shardan13]

When I said that grav tanks with thicker bottom having an advantage I meant that they had less to fear when flying higher than their opponents. They are less vulnerable to enemy fire. Sorry I didn't explainer it better earlier.

Also I understand the problem of cost, size and armor. I home brew military grav vehicles with top and bottom armor as thick as their front armour to provide protection against land mines against the bottom and missiles and drone dropped grenades from the top. I came to the conclusion that starting a land based war in Charted Space is both stupid or expensive. Either you have grav vehicles with blown out floors or roofs (such as Russia is experencing currently with it's current non-grav vehicles) or have vehicles to hideously expensive to use.

 

[Condottiere]

Weber probably has it correct that once an interstellar navy has orbital control, the planet should surrender.

Terra decided to make a fight out of it, and canon has it that the Imperium Army was royally chewed up and spit out, before they managed to suppress most of the resistance, which more likely explains the Imperium agreeing to the armistice.

However, we're dealing with limited budgets and mercenaries who have to get their own logistics chain in order.

 

[Shardan13]

Weber probably has it correct that once an interstellar navy has orbital control, the planet should surrender.

Terra decided to make a fight out of it, and canon has it that the Imperium Army was royally chewed up and spit out, before they managed to suppress most of the resistance, which more likely explains the Imperium agreeing to the armistice.

However, we're dealing with limited budgets and mercenaries who have to get their own logistics chain in order.

Which explains why in Charted Space most mercenaries are infantry experts.

 

[Condottiere]

Flexible and cheaper per shipping tonne.

 

[AnotherDilbert]

This may be a tangent to the discussion, but wouldn’t the slow rate of fire of High Guard weapons make them far less desirable for combat vehicles? I didn’t think their rate of fire (once every 6 minutes) would change based on being mounted on a standard vehicle instead of a starship.

They have never had a slow rate of fire, they just make an attack roll less often. I think we can assume an attack each round, just like in space dogfights.

I assumed part of the reason behind the longer combat rounds was that the High Guard weapon systems often used so much energy to be effective at such long ranges that they needed a cool down period of some sort between firings. This could even apply to missile systems as the launchers can’t spit out missile like bullets.

It's just difficult to hit at longer range, you need a few shots to get a hit.


FF&S required a RoF of ten shots per space combat round to get a single normal attack.

 

[AnotherDilbert]

An argument that can be made that grav tanks are ground hugging is that grav tanks weak point is their floor. It and the top armor are the thinnest and unlike the top is undefended by weapons. So anyone attacking a grav tank will aim at its floor.

That's just a design choice, just like side armour relative to front armour.

 

[Condottiere]

Rate of fire is unclear for spacecraft weaponry, since they introduced the dogfight round.

Logic would indicate fire control and fratricide would limit missile launches, while energy weapons by the available power pool and overheating.

 

[Sigtrygg]

An argument that can be made that grav tanks are ground hugging is that grav tanks weak point is their floor. It and the top armor are the thinnest and unlike the top is undefended by weapons. So anyone attacking a grav tank will aim at its floor. The attacked grav tank facing many types of military grav vehicles will seek to be below them so its turret weapon can aim up. The lowest both attackers can get is ground hugging height.

As an aside this suggests that a grav tank with bottom armor as thick as its front armor may have an advantage over those that don't.

Only if the designer is stupid.
A gunship or grav tank as the fanon insists on calling them is more akin to an attack helicopter with M1 armour, and since it can be hit from any direction you armour it uniformly, just like you do with starships.

 

[Shardan13]

That's just a design choice, just like side armour relative to front armour.

Yes, but it is choice that nearly all grav tanks have made. There are examples of grav vehicles with weapons on their undersides like the Walkure Fighting Grav Assult Vehicle from the vehicle handbook but they seem to be confined mostly to light armor vehicles.

A cleaver opponent will always develop a way to attack the weakest point and a clever defender will avoid exposing that weak point. The design of a vehicle armor and the location of its weapons will affect how it is used. If the underside is the weakest point then it is best to avoid exposing it to enemy fire.

 

[Shardan13]

Only if the designer is stupid.
A gunship or grav tank as the fanon insists on calling them is more akin to an attack helicopter with M1 armour, and since it can be hit from any direction you armour it uniformly, just like you do with starships.

Yes you are right but the examples shown in the vehicle handbook don't have uniform armor, pg 34 of that book states that roofs and floors are half the Protection rounded down. Also they tend to have heavy front armor, lesser side armor and weak rear armor. It implies that the designers expected that most attacks will strike the front. I'm sure in universe that the Imperial Army had serious talks with the designers after the battle of Terra and showing them pictures of military grav vehicles with every side punctured except for the front. The designers then said that the army can have it better protected vehicles at the cost of increased price and size.

 

[Condottiere]

Diamond profile seems optimal, assuming ninety degree attack vectors.

 

[Shardan13]

Diamond profile seems optimal, assuming ninety degree attack vectors.

I don't think the vehicle handbook covered that but I like to be proven wrong.

 

[Condottiere]

 

[Shardan13]

Condottiere, I meant I like to be proven wrong by the rules in the vehicle handbook. When you mentioned diamond profiles I imagined you meant something else, I was vaguely aware of the triangular bottom vehicles that were developed to protect against IDEs.

 

[Condottiere]

It's not in Mongoose, but there are sloping options for armour facings, which would increase the amount of armour thickness that a shot has to penetrate.

What's not mentioned would be that explosive effects would be deflected if you do have a triangular facing, mostly because Striker and Fire Fusion Steel were written before practical experience in Iraq and Afghanistan.

Again, I suppose experience decided that blocky facings were better against penetration, maybe because you can stuff more composite armour onto the tank, especially the turret, which you'll note is where late Cold War NATO tank design diverges from Warsaw Pact.

The diamond profile is an observation from myself, which was triggered by the altitude discussion, and an accumulation of Russian tank follies, where they're getting screwed from all directions.

Generally, and presumably, in a gravitated environment, least distance means ninety degree angles for projectiles, or in our case, energy beams, plus overhead delivery, so a diamond profile would place maximum material between the interior and the incoming ordnance, if not deflect it.