TNE FF&S Hypervelocity Smoothbore guns

[snrdg082102]

Evening all,

In CT Striker guns are typed as mortar, low velocity/howitzer, medium velocity, high velocity, or hypervelocity.

TNE Chapter 3 D. Range 1. Direct Fire Range states that hypervelocity smooth bore guns modify the range.

What muzzle velocity in m/s is considered hypervelocity?

I found a couple of sources that indicate that hypervelocity starts somewhere around 2,500 m/s and in atmosphere be a maximum of 4,500 ms.

For that matter what is the muzzle velocity range in m/s for a mortar, low velocity/howitzer, medium velocity, and high velocity guns?

 

[snrdg082102]

From jec10 in a PM

Tom,

FF&S largely moved away from the CT/MT low/med/hivel distinctions in favour of letting you design any type of CPR gun using the length of the barrel in calibres as the key determinant. You'll see in FF&S that once you have a bore size and barrel length you can then work everything else out.

So a howitzer in FF&S has a relatively short barrel length (~30 calibres), a mortar even shorter (~10 calibres) and so on. They actually discuss it on page 107 at A.3.

Regarding HVSB, essentially FF&S assumes that any kinetic penetrator round at TL7+ is being fired by a HVSB and takes the modifiers at D.1.

 

[snrdg082102]

My reply

Afternoon jec10,

Thanks jec10 for the reply.

Unfortunately, FF&S Book 3 Chapter 3 D. Range 1. Direct Fire Range on page 108 states that "Hypervelocity smoothbore guns available at TL 7 and higher generate higher muzzle velocities with shorter barrel lengths. To reflect this, multiply range by the following TL modifiers."

I don't have a clue as to what FF&S considers a hypervelocity gun based on either the muzzle velocity or muzzle energy

From jec10 in a PM
Tom,

FF&S largely moved away from the CT/MT low/med/hivel distinctions in favour of letting you design any type of CPR gun using the length of the barrel in calibres as the key determinant. You'll see in FF&S that once you have a bore size and barrel length you can then work everything else out.

So a howitzer in FF&S has a relatively short barrel length (~30 calibres), a mortar even shorter (~10 calibres) and so on. They actually discuss it on page 107 at A.3.

Regarding HVSB, essentially FF&S assumes that any kinetic penetrator round at TL7+ is being fired by a HVSB and takes the modifiers at D.1.

 

[Piper]

don't have a clue as to what FF&S considers a hypervelocity gun based on either the muzzle velocity or muzzle energy

FF&S doesn't classify CPR guns on this basis. The TL7+ introduction of fin-stabilized rounds fired from high velocity smooth bore guns required a break in the direct fire range formula. These are given in the table. In essence, all CPR guns of TL7+ are considered "hypervelocity smooth bores".

The real difference starts to show up when calculating KEAP penetration.

 

[snrdg082102]

Evening Piper,

Thanks for the help unfortunately my mind is still not getting a handle on the rule after calculating muzzle velocity from muzzle energy.

If my calculations are correct a TL 10 45 cm 10 Caliber smoothbore CPR gun has a muzzle velocity of 400 m/s which I don't even consider this close to being to hypervelocity.

FF&S doesn't classify CPR guns on this basis. The TL7+ introduction of fin-stabilized rounds fired from high velocity smooth bore guns required a break in the direct fire range formula. These are given in the table. In essence, all CPR guns of TL7+ are considered "hypervelocity smooth bores".

The real difference starts to show up when calculating KEAP penetration.

 

[Piper]

If my calculations are correct a TL 10 45 cm 10 Caliber smoothbore CPR gun has a muzzle velocity of 400 m/s which I don't even consider this close to being to hypervelocity.

I'll take your calculations as a given because it's way too early in the morning for me to extrapolate muzzle energy and derive velocities.

Now run your gun through the direct fire range calculations on p. 108, D1:

R=5(4.5+10+20)

therefore: R=172.5

The next step is what's giving you grief. Starting at TL7, CPR guns receive a short range modifier (x 1.45 in the case of your design).

"Hypervelocity smoothbore guns available at TL 7 and higher generate higher muzzle velocities with shorter barrel lengths. To reflect this, multiply range by the following TL modifiers:"

Note that no limiting factors are given. There is no minimum muzzle energy required to gain this bonus and at no point in the design sequence is a gun defined as either "hypervelocity" or "smoothbore". All CPR guns at TL7+ receive this bonus without regard to muzzle energy or barrel length in calibers. The terms "hypervelocity" and "smoothbore" are essentially "chrome" and not part of the design sequence.

The true determining factor (in FF&S terms) is penetration. Look at the KEAP penetration entry on p. 140, section F2. Your design is capable of firing APFSDSCI penetrators. It has this ability due entirely and solely to tech level. There are, once again, no limiting factors due to muzzle energy or barrel length. The weapon derives the benefits of the technology regardless of muzzle velocity.

The essay on pp. 135-136 covers the factors governing KEAP penetration in detail. If it makes it any easier to swallow, you might choose to look at FSDS rounds as being hypervelocity in relation to "normal" rounds.

Regards

 

[snrdg082102]

Thanks Piper that makes more sense, unfortunately I'm a little busy taking care of my Mom after her knee surgery.

Have a good one.

I'll take your calculations as a given because it's way too early in the morning for me to extrapolate muzzle energy and derive velocities.

Now run your gun through the direct fire range calculations on p. 108, D1:

R=5(4.5+10+20)

therefore: R=172.5

The next step is what's giving you grief. Starting at TL7, CPR guns receive a short range modifier (x 1.45 in the case of your design).

"Hypervelocity smoothbore guns available at TL 7 and higher generate higher muzzle velocities with shorter barrel lengths. To reflect this, multiply range by the following TL modifiers:"

Note that no limiting factors are given. There is no minimum muzzle energy required to gain this bonus and at no point in the design sequence is a gun defined as either "hypervelocity" or "smoothbore". All CPR guns at TL7+ receive this bonus without regard to muzzle energy or barrel length in calibers. The terms "hypervelocity" and "smoothbore" are essentially "chrome" and not part of the design sequence.

The true determining factor (in FF&S terms) is penetration. Look at the KEAP penetration entry on p. 140, section F2. Your design is capable of firing APFSDSCI penetrators. It has this ability due entirely and solely to tech level. There are, once again, no limiting factors due to muzzle energy or barrel length. The weapon derives the benefits of the technology regardless of muzzle velocity.

The essay on pp. 135-136 covers the factors governing KEAP penetration in detail. If it makes it any easier to swallow, you might choose to look at FSDS rounds as being hypervelocity in relation to "normal" rounds.

Regards

 

[snrdg082102]

Copy and paste from PM,

Morning jec10 and thanks for the continued help. I think between you and Piper I may be getting the idea of the rule.

Like I said, I think you'll find they just decided to have a modifier improving the range of all TL7+ KEAP rounds. They aren't bothered with specifically defining what a HVSB is or is not. It is an 80:20 solution but not one that has ever bothered me. If you are firing a KEAP round AND it is TL7+ then you apply the modifier and get a longer range performance. Otherwise you don't.

 

[Antony]

Personally I just assumed it was the propellent for the CPR guns shells which made them hypervelocity. I also assumed that that the guns were tough enough at these tech levels to take the increased pressure in the barrel that this more potent propellent would produce.

 

[Timerover51]

FF&S doesn't classify CPR guns on this basis. The TL7+ introduction of fin-stabilized rounds fired from high velocity smooth bore guns required a break in the direct fire range formula. These are given in the table. In essence, all CPR guns of TL7+ are considered "hypervelocity smooth bores".

The real difference starts to show up when calculating KEAP penetration.

If all guns are considered "hypervelocity smoothbores" where do mortars and howitzers fit in? By definition, those are low to medium velocity pieces.

 

[Piper]

If all guns are considered "hypervelocity smoothbores" where do mortars and howitzers fit in? By definition, those are low to medium velocity pieces.

Yes, they are in terms of real-world definitions but the FF&S design sequence doesn't classify CPR guns by muzzle velocity.

In FF&S mortars have their own, slightly modified design sequence. Everything else is simply a "gun" and, as no limiting factors are defined, all guns receive a direct fire range bonus at TL7+.

 

[Timerover51]

Yes, they are in terms of real-world definitions but the FF&S design sequence doesn't classify CPR guns by muzzle velocity.

In FF&S mortars have their own, slightly modified design sequence. Everything else is simply a "gun" and, as no limiting factors are defined, all guns receive a direct fire range bonus at TL7+.

And when the Real World conflicts with the game, it is the Real World that is wrong.

 

[snrdg082102]

Evening all,

My apologies for not getting back to you all sooner, I've been involved in a family medical issue which appears to be coming to an end with the family member recovering nicely.

Propellant and barrel length determine the muzzle energy which needs to be converted to muzzle velocity. TNE FF&S uses muzzle energy based on a barrel length of 60 calibers. Using hypervelocity smoothbore doesn't really help in determining what gun fits the description, which is what has me confused.

The game world is not the real world so neither is wrong.

Have a happy 2013

 

[Piper]

jec10 summed it up best so I'm quoting it again here:

From jec10 in a PM

Tom,

FF&S largely moved away from the CT/MT low/med/hivel distinctions in favour of letting you design any type of CPR gun using the length of the barrel in calibres as the key determinant. You'll see in FF&S that once you have a bore size and barrel length you can then work everything else out.

So a howitzer in FF&S has a relatively short barrel length (~30 calibres), a mortar even shorter (~10 calibres) and so on. They actually discuss it on page 107 at A.3.

Regarding HVSB, essentially FF&S assumes that any kinetic penetrator round at TL7+ is being fired by a HVSB and takes the modifiers at D.1.

I gotta ask; why are you calculating muzzle velocity? The design sequence doesn't use it, it's strictly based on muzzle energy.

Using ME instead of a low/med/high velocity broad brush definition gives the design sequence a finer grain, allowing you to create a much wider range of performance characteristics. Compare the CPR sequence to the grenade launcher sequence on p. 147 (which does use a low/med/high velocity system).

My best advice to you is to simply ignore the term "hypervelocity smoothbore" (because it's not defined anywhere in the design sequence rules) apply the range modifier to your designs (if the TL is appropriate) and move on.

 

[snrdg082102]

Morning Piper,

Three sections of TNE Book III Chapter 3 CPR Guns design sequence appear to me to contradict each other.

Step A Specification 3 Barrel length page 107 states that as a general rule, I guessing rifled bores, hypervelocity guns have barrels 60 to 70 calibers long which to me is a vague definition.

As pointed out the TNE CPR gun design sequence uses muzzle energy not velocity. Step A Specifications 7 Muzzle Energy page 107 states that for calibers > 20 and < 60 muzzle energy is reduced by 2% per caliber. For calibers less than 20 the muzzle energy is reduced by 1% per caliber.

Looking at the CPR Gun Table on TNE FF&S page 109 per Step A 7 the listed muzzle energies are guns of 60 calibers with I think have rifled bores.

Step D Range 1. Direct Fire Range page 108 states that "Hypervelocity smoothbore guns available at TL 7 and higher generate higher muzzle velocities with shorter barrel lengths. To reflect this, multiply range by the following TL modifiers:"

Had the authors not tossed in the tidbit about TL 7+ hypervelocity smoothbore muzzle velocities with shorter barrel lengths having a direct fire range modifier I wouldn't be confused. Of course I do seem to take things very literally at times.

jec10 summed it up best so I'm quoting it again here:


I gotta ask; why are you calculating muzzle velocity? The design sequence doesn't use it, it's strictly based on muzzle energy.

Using ME instead of a low/med/high velocity broad brush definition gives the design sequence a finer grain, allowing you to create a much wider range of performance characteristics. Compare the CPR sequence to the grenade launcher sequence on p. 147 (which does use a low/med/high velocity system).

My best advice to you is to simply ignore the term "hypervelocity smoothbore" (because it's not defined anywhere in the design sequence rules) apply the range modifier to your designs (if the TL is appropriate) and move on.

 

[Timerover51]

The game world is not the real world so neither is wrong.

My apologies. I will avoid any more discussions of weapons and equipment design sequence.

 

[snrdg082102]

Evening timerover51,

I don't mind discussions on the design sequences but stating that either the game world or real world is wrong is not helping answer the question in the thread.

My apologies for the short but direct reply. The designers purposely pared down the real world mechanics to simplify the design. Individuals, like myself and obviously you, would like the game world to be closer to the real world.

My recommendation is to submit an alternate method to FFE as an update or supplement to the design rules.

First thank you for the help with CT Striker, any help that answers my questions within the context of any Traveller version design sequence, and my apologies for offending you with my reply.

My apologies. I will avoid any more discussions of weapons and equipment design sequence.

 

[Piper]

Step A Specification 3 Barrel length page 107 states that as a general rule, I guessing rifled bores, hypervelocity guns have barrels 60 to 70 calibers long which to me is a vague definition.

This is described in the text as a "general rule of thumb". As I read it, it's intended to give you a starting point for your designs.

For example, a tank gun would typically be designed for direct fire with an emphasis on anti-armor capability. A long barrel (60 to 70 calibers) provides significant advantages in muzzle energy so, if you're designing a tank gun, start with a long barrel.

A howitzer would be designed primarily for indirect fire. While a high muzzle energy does give greater range, the reduced weight, reduced cost and faster reload times of a short barrel could easily offset this. So, as a rule of thumb, if you're designing a howitzer, start with a shorter barrel ("about 30 calibers" in that paragraph you quoted).

Note that these are guidelines only. FF&S allows you to design a very wide range of guns without limiting you to low/med/hi velocity or howitzer vs. gun definitions. You can create anything from huge-bore stubby mortars to railway guns or anything in between.


(big snip)

Looking at the CPR Gun Table on TNE FF&S page 109 per Step A 7 the listed muzzle energies are guns of 60 calibers with I think have rifled bores.

Step D Range 1. Direct Fire Range page 108 states that "Hypervelocity smoothbore guns available at TL 7 and higher generate higher muzzle velocities with shorter barrel lengths. To reflect this, multiply range by the following TL modifiers:"

All I can tell you here is that you have to ignore references to rifled and smoothbore. They're not part of the design sequence.

Had the authors not tossed in the tidbit about TL 7+ hypervelocity smoothbore muzzle velocities with shorter barrel lengths having a direct fire range modifier I wouldn't be confused. Of course I do seem to take things very literally at times.

I hear ya

 

[snrdg082102]

Evening Piper,

Thanks for the reply and attempting to get me unconfused.

The problem is that below TL 7 CPR guns have, per Book III Chapter 9 page 136, rifled bores. At TL 7 the solution is dispense with rifling all together and use fins to stabilize the. However some of the earlier finned stabilized rounds used a hybrid system for use in existing rifled bores.

This means to me that not all TL 7 guns are smooth-bored weapons and the table on page 109 is probably developed for rifled bore CPR guns. In TNE the various factions are trying to discover what happened to the parts of the Imperium that have been out of contact since the Civil War in MT.

Of course I'm probably reading to much into the sequence as usual.

This is described in the text as a "general rule of thumb". As I read it, it's intended to give you a starting point for your designs.

For example, a tank gun would typically be designed for direct fire with an emphasis on anti-armor capability. A long barrel (60 to 70 calibers) provides significant advantages in muzzle energy so, if you're designing a tank gun, start with a long barrel.

A howitzer would be designed primarily for indirect fire. While a high muzzle energy does give greater range, the reduced weight, reduced cost and faster reload times of a short barrel could easily offset this. So, as a rule of thumb, if you're designing a howitzer, start with a shorter barrel ("about 30 calibers" in that paragraph you quoted).

Note that these are guidelines only. FF&S allows you to design a very wide range of guns without limiting you to low/med/hi velocity or howitzer vs. gun definitions. You can create anything from huge-bore stubby mortars to railway guns or anything in between.


(big snip)



All I can tell you here is that you have to ignore references to rifled and smoothbore. They're not part of the design sequence.



I hear ya

 

[Piper]

I think I understand where you're coming from.

Because the terms "rifled", "smoothbore" and "hypervelocity" appear in the text (and actually within the design sequence on p. 108, D1) you feel that some stage in the design sequence should define this. This isn't unreasonable, but there is nothing in the design sequence or the published errata that I've found that clears this up.

Personally, I don't believe that this is an error. It's my opinion that the "magic" that occurs at TL7+ isn't due to whether or not a gun is rifled or what the actual muzzle velocity is. It's due to the introduction and general use of FSDS ammunition, specifically the ability to mass produce long rod KE pentrators from extremely hard and/or dense materials. But then, there's nothing in the design sequence that actually states this, either.

I'm really sorry I couldn't clear this up for you, Tom.