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Advanced grav tanks - why do they have turrets?

How fast does a grav tank stop at any speed?


Zparkz,

Why is everyone continuing to assume that grav tanks routinely move at their top speed on the battlefield?

All the problems associated with high speeds have been note, stuff like a huge sensor signature, NOE problems, turning, stopping, all of it. Yet the thread is still blithely assuming that grav tanks zip around in battle at 600+ kph.

How much space does a grav tank need to turn?

Not much if it's moving like a tank and not zipping along at 600+ kph.

FASA had a tank game for Renegade Legion that had very good rules for tank movement. That game treated the tank like it was on ice. only the air friction stopped it from moving, if thrust was dropped.. Maybe it could be possible to adapt those rules to Traveller?

That sounds like a nice idea. Of course you don't need to worry about your grav tanks acting like hockey pucks when their thrust is lost if they aren't moving at 600+ kph in battle in the first place.

I'll explain this once again.

Grav tanks can use their high speed to travel to and from orbit, make strategic deployments, and undertake operational movements. However when grav tanks enter an environment in which the enemy can target them, such high speeds are a deadly liability.

In a tactical, as opposed to a strategic or operational sense, all gravitics allows you is movement across previously forbidden terrain. Gravitics means tanks needn't worry about ground pressure like their tracked bretheren, so they can move through swamps, over snow and ice, and cross rivers and other bodies of water at will. Grav tanks still fight like tanks however, no matter what sort of "ground" is beneath them. They use hull down positions, sprint from point to point at manageable speeds, and cover each other during movement. In combat grav tanks move and fight like tanks. That's why they're shaped like tanks.

In a 57th Century battlefield full of tac-missiles, plus direct and indirect energy weapons, if you fly you die. If, in an area in which an enemy can potentially see you, you're moving so fast that you can't turn sharply, slow rapidly, or stop quickly, then all you've done is hang out your ass to be shot off.

Form follows function. Grav tanks look like tanks because they fight like tanks. Period.


Bill
 
Sounds good. Know what it was called? That's an adaptation I wouldn't mind trying - except, of course, old rulesets are too difficult to get hold of.

<wrestles with own hand to stop it writing another tirade against copyright rules that benefit nobody> ;)

Renegade Legion: Centurion
 
Zparkz,

Why is everyone continuing to assume that grav tanks routinely move at their top speed on the battlefield?

All the problems associated with high speeds have been note, stuff like a huge sensor signature, NOE problems, turning, stopping, all of it. Yet the thread is still blithely assuming that grav tanks zip around in battle at 600+ kph.

I am not assuming the speeds will be 600+ thats why I wrote at any speed.

That sounds like a nice idea. Of course you don't need to worry about your grav tanks acting like hockey pucks when their thrust is lost if they aren't moving at 600+ kph in battle in the first place.

Either way you cut it, grav tank movement will be way different than ground tanks. However as they do not have other friction to worry about than air. They will be like a hockey puck on ice regarless of speed. Of course slower moving may be easier to control and stop quickly. However grav tanks will be affected by wind, cose by explosions. Station keeping may be a pain.
 
Sounds good. Know what it was called? That's an adaptation I wouldn't mind trying - except, of course, old rulesets are too difficult to get hold of.

<wrestles with own hand to stop it writing another tirade against copyright rules that benefit nobody> ;)

Just from memory, as I had the game many years ago. Movement was thrust based almost like starship combat. Moving up or down gained or lost speed. Control may also be affected by moving up and down over terrain (assuming NOE altitude). Forests was a pain to navigate.

Renegade Legion: Centurion; may be found on ebay at times.
 
Zparkz,

Why is everyone continuing to assume that grav tanks routinely move at their top speed on the battlefield?
no one is. You're the one assuming the rest of us are assuming that.


Form follows function. Grav tanks look like tanks because they fight like tanks. Period.

And the form of the trepida (at least in MT) is different from modern tanks.

highly streamlined pentagonal shaped body, wedge shaped main turret, dual miniturrets highly streamlined on sides of the main turret deck. Aspect ratio aprox 2x4.5x6; hull is 1x4.5x6, turret 1x4x4, with barrel extending another 2 units... that barrel is about 3m long.

It's designed for speed. Or more correctly, drawn that way. smooth.

It's probably going to be scooting abut at about 60-120 kph (NOE limit is 180), and it can adjust mps by about 25mps2... or 7kph/sec.

It's operation speed is much the same as a combat helo NOE. (Heck, modern NOE avionics allow speeds in excess of 100kph.

It's about 3m tall, 7.5m wide, and about 12m long... with the hull being 2m tall. Thats effectively a 7.5x6m rectangle and a 7.5x6m triangle, and 1m x 6m x9m for the turret, with similar proportions.

For the metric impaired... 9' 9" tall, 24' 7" wide, and 39' 3" long. That's the size of 3 buses.... side by side. it's a LOT bigger than most tanks.

And the M1 is about 9' 6" tall, 11' 5" wide, and 26 feet long body, with the main gun extending another 6' ... (source)

You can add about 18" of ground clearance, as well...

They superficially look similar, but a critical eye shows the 60mph+ abrams makes few considerations for streamlining, and has different proportions.


Same height, but the trepida's about 2x as wide, and 1.5 times as long, much more smooth, and just plain "bigger and faster"

Now, comparing to the Hind (Mi24) 17.5m long,, 6.5m tall, 6.5m wingspan, 17.5m rotor diameter. that's about the same size, and mobility. roughly 50 Td stowed... but probably about 15 actual. Fairly smooth, rounded edges,

Then we get to the weapons. The Trepida is a DF weapon, an RPX-14, much like attack helos have DF chainguns. The M1 has, like most tanks, a hivel gun, capable of direct and indirect fire...

Plain and simple, if the trepida can't see it, it can't hit it. Much like an attack helo.

If it can't fly upside down, then yes, it will operate much like a hybrid of a tank, a helo, and a GEV... and it looks somewhere between the lot.
 
>However as they do not have other friction to worry about than air. They will be like a hockey puck on ice regarless of speed.

if its heavily armoured, turn off the anti-grav and nature will cause you to brake .... what do you care about in any combat vehicle anyway .... the farmers field etc or dodging that weapon blast ?

I think the Hammers Slammers aircushion tanks are a more reasonable model for a-grav tanks in actual combat than turn-on-a-dime or puck-on-ice .... out of danger they probably rise higher off the ground and then could act more like pucks until they go into full a-grav flight mode and operate like "UFO's"
 
if its heavily armoured, turn off the anti-grav and nature will cause you to brake .... what do you care about in any combat vehicle anyway .... the farmers field etc or dodging that weapon blast ?

And that will be crashing. Do you want to plow a 100ton+ tank into the ground at 60km/h? That tank will probably not fly again regardless of the ground material you plow it into.
 
A few points:

1) Thanks for the game name. I'll add it to the list... :)

2) I'm not assuming ultra-high speed, but even 60-120kph will take some stopping - according to Aramis, some 10 - 20 seconds (watch out for that farmhouse...) and that's using the MT spec with several Gs on tap. The TNE version mentioned above with fractional G thrust would take a couple of minutes to stop...
Maybe function follows form - they crawl like a tank because they don't have aerodynamic braking.

3) You could perhaps reduce your lift gradually and skid to a halt without doing too much damage to your armour, but I can't see it being standard practice.

4) Station keeping shouldn't be a problem, because once your speed is low enough, the drive can compensate. The ice analogy breaks down at low speed.
 
4) Station keeping shouldn't be a problem, because once your speed is low enough, the drive can compensate. The ice analogy breaks down at low speed.

That depends on rulesett used. In MT and maybe CT the grav modules also produce thrust. And this thrust doesn't have a limit on direction relative to facing. However if you use TNE as rules you are limited to the thrust system which usually is in the aft. There may be vector thrusters, but they won't be as strong as the main thruster.

If you need to rotate the hull to compensate for wind drift, you may end up exposing a lesser armored side towards the enemy.
 
A few points:

1) Thanks for the game name. I'll add it to the list... :)

Interesting set of games. Some interesting wargame concepts that I haven't seen elsewhere that are interesting simulation tricks. Armour and attack shaping come to mind.

Interceptor (spacefighter) and Leviathan (Capital Ship) were also not too bad. The full ruleset for interceptor are at http://madcoyote.com/renleg/int/int.html . The combat chapter has the interesting damage/armour system.

Returning to the snark and absolutism of the grav tank discussion. :)
 
Interesting set of games. Some interesting wargame concepts that I haven't seen elsewhere that are interesting simulation tricks. Armour and attack shaping come to mind.

Interceptor (spacefighter) and Leviathan (Capital Ship) were also not too bad. The full ruleset for interceptor are at http://madcoyote.com/renleg/int/int.html . The combat chapter has the interesting damage/armour system.

Returning to the snark and absolutism of the grav tank discussion. :)

I regret that I threw away the games many years ago. (prior to ebay came to existence). We had a scream with the Interceptor game. Often playing to the early hours. I regretfully only played centurion twice. I feel that Centurion would make a good adaption to Traveller regardless of Traveller edition.

Maybe I should search the ebay for a copy.
 
I'd think the reason the "Trepida" tank has a lot or aerodynamic features is NOT because it needs to have lots of speed in combat, but rather because it is ABLE to have lots of speed out of combat.

Especially if you go with the idea that these things are low orbit drop tanks. Ground approach can be hot and fast. Much better to be sleek than square for a variety of reasons.

It also doesn't hurt that aerodynamic design also offers direct-fire sloped armor advantages.

I'm with Bill on this one. Grav Tanks are great because they offer a lot of strategic advantages to movement, but once in the battle area, they tend to go relatively low and relatively slow.
 
And the form of the trepida (at least in MT) is different from modern tanks.

Not critically IMHO. At the end of the day, it is a vehicle with a large turret mounting a large weapon.

Sounds like a tank to me.

And I'm not real sure that the shape of the Trepida hull is particularly feasible (i.e., I think it's an artistic construct, not a functional one based on a reasoned analysis of what grav tank combat will likely look like).

In particular, the wedge shape could prove to be highly vulnerable against kinetic energy penetrators. The reason is that radically sloped armor no longer provides the benefit it did in the 1960s and earlier. A radically sloped armor plate weighs the same as a non-sloped plate with the same line-of-sight thickness. However, the actual *thickness* of the sloped plate is far less than the non-sloped plate. Since plate thickness is a key manufacturing bottleneck, highly sloped armor plates are desirable to maximize ease of production. And, until modern APFSDS penetrators came along, sloped armor was just as good (and against some ammunition slightly better) as non-sloped armor.

However, modern APFSDS penetrators are designed to actually "turn into" a sloped plate. As a result, a sloped plate offers *less* protection than a non-sloped plate with the same LOS thickness. And composite armor arrays are much easier to manufacture in thick slabs than steel plates are.

That's why modern tanks like the Leopard II and Abrams have relatively modest sloping (and in the case of the Leopard IIA1-A4 none at all).

In addition, tanks simply cannot carry enough armor to protect all faces. Indeed, modern MBTs often choose to armor the turret far more than the hull. The result is that weight forces modern MBTs to be well-protected from the front (only). And sometimes, only the turret is capable of resisting MBT class armament. Wedge shaped configurations like the Trepida will require far more surface area than a traditional design. I seriously doubt that they will be competitive with more traditional designs (i.e. relatively narrow box shape).

FWIW, my FFT3 partner (an MIT Materials Science Grad) is also extremely skeptical of the ability of grav tanks to be very maneuverable at high speeds.

I think that at the end of the day, Traveller style grav tanks will tactically resemble extremely fast tanks that can traverse most terrain. They will *not* resemble helicopters so much (although light grav tanks might).
 
Grav tanks are very flexible, and can act like lots of things, depending on the situation. They can pop up like a helicopter, or creep like a tank, or strafe like a plane, or even hover high and snipe.
 
IMTU, it's not uncommon to see port control using trepidas as "intercept" craft.

It can go Mach 1+, it's able to take 1-2 hits from starship weapons, and it's highly maneuverable. (At speed, it locks the gun forward for stability... but it can still hurt most non military craft..)
 
Grav tanks are very flexible, and can act like lots of things, depending on the situation. They can pop up like a helicopter, or creep like a tank, or strafe like a plane, or even hover high and snipe.

Similarly, a modern tank can do all kinds of outrageous things -- ram foes, drive at full speed through enemy forces, etc. -- if its opponents lack antitank weaponry (or the skill to use them effectively). For instance, the "Thunder Run" by Task Force 1-64 Armor, 3ID in Operation Iraqi Freedom. (A battalion task force essentially just drove through Baghdad and shot up the place.)

But in a normal combat environment, that won't work. Had the task force faced adequately trained forces with modern AT weapons, the operation would have been a costly failure.

And grav tanks, in a normal combat environment, will generally act like modern MBTs, albeit with far better mobility. And, depending on sensor tech, they may use pop-up attacks against other tanks. Depends on whether the opposing tank's sensors and targeting systems can shoot the popping-up tank.

All IMHO of course.
 
I notice that the term tank disappears from the military vehicles description by TL section of LBB4.

TL-11 all vehicles have pronounced free-flight capability.

TL-12 all vehicles have sufficient free-flight performance that ground combat vehicles effectively no longer exist, having merged with aircraft. The primary weapon of the heavy gunships...

there you go - no such thing as a grav tank past TL11 ;)

The term gunship is also used at TL14 and 15.

Which brings me to ground hugging grav tanks at TL15. They are all dead, every last one of them thanks to meson artillery.
 
Good point - they aren't going to stay long in one place either.

The only way for a vehicle to survive a high TL battlefield is mobility IMHO - hull down don't work when mesons are coming at you.

Using terrain as cover with an onboard fusion reactor???

neutrino sensors, densitometers etc.

Move or die - never mind fly and die.

You have point defence to take out tac missiles, anti-laser sprays, ecm etc.

The main threats are the enemy's main guns and artillery.

Keep moving and not in predictable straight lines either.
 
Which brings me to ground hugging grav tanks at TL15. They are all dead, every last one of them thanks to meson artillery.

Well, if they're sitting stationary perhaps.

If you're moving then to get killed - other than by a fluke shot - you need to be detected, and your future path predicted accurately (and other FC stuff too).

Flying out of NoE would increase detectability IMHO.

As an aside, IMTU meson artillery has a minimum effective range within which it has no effect - as the mesons haven't had time to decay. Bit closer to real world physics, as Traveller meson guns work (in part) by using relativistic speeds to *delay* meson decay. Meson artillery would require the *acceleration* of meson decay. Could be handwaved, but too much handwavium does not a good setting make.

Guess they could fire from the other side of the planet though ;D
 
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