63 replies to this topic

[Sneaky B]

Made a few adjustments on errors I've overlooked

[Sneaky B]

I've run some numbers and apparently the tip of a seven meter long katana could reach 219.91 m/s if swung at a rate of 300 rpm or 5 full circles per second. That is 491.92 mph or 791.67 kph or M=0.6462@Sea Level ISA.

As for the dimensions:
Nagasa (Length) = 721 cm
Mihaba no Mune-Machi (Distance from spine to blade near hilt) = 32 cm
Mihaba no Yokote (Distance from spine to blade near tip) = 24 cm
Kasane no Mune-Machi (Thickness near hilt) = 6.4 cm
Kasane no Yokote (Thickness near tip) = 5.1 cm

Total volume of the blade = 77,394.25 cm³
Mass of the blade = 3,000 kg
Density of the blade = 38.76 g/cm³

Density of steel for comparison = 8.05 g/cm³
Density of tungsten for comparison = 19.25 g/cm³
Density of Depleted Uranium for comparison = 19.1 g/cm³

A katana moving at 219.91 m/s generates an energy of 72,540,612.15 J.
A .50 BMG's (M903 SL:AP) muzzle energy on the other hand is 17,360 J.

Edited by Sneaky B, 09 August 2012 - 12:56 PM.

[Bishop Steiner]

Sneaky B, on 09 August 2012 - 12:19 PM, said:

I've run some numbers and apparently the tip of a seven meter long katana could reach 219.91 m/s if swung at a rate of 300 rpm or 5 full circles per second. That is 491.92 mph or 791.67 kph or M=0.6462@Sea Level ISA.

As for the dimensions:
Nagasa (Length) = 721 cm
Mihaba no Mune-Machi (Distance from spine to blade near hilt) = 32 cm
Mihaba no Yokote (Distance from spine to blade near tip) = 24 cm
Kasane no Mune-Machi (Thickness near hilt) = 6.4 cm
Kasane no Yokote (Thickness near tip) = 5.1 cm

Total volume of the blade = 77,394.25 cm³
Mass of the blade = 3,000 kg
Density of the blade = 38.76 g/cm³

Density of steel for comparison = 8.05 g/cm³
Density of tungsten for comparison = 19.25 g/cm³
Density of Depleted Uranium for comparison = 19.1 g/cm³

A katana moving at 219.91 m/s generates an energy of 72,540,612.15 J.
A .50 BMG's (M903 SL:AP) muzzle energy on the other hand is 17,360 J.

Is that RPM rate realistically attainable? While mechs are not slow like loader exoskeletons, they aren't martial artists, either. I would be surprised if it could swing the blade ONE full rotation per second. (Just playing devils advocate)

Also, what is the deceleration and energy absorbed BY the blade when it comes to a screeching halt against 100 tons of immovable object?

[Sneaky B]

Well, I wasn't sure myself how fast the blade would swing because No-Dachi are equipped with triple strength myomer. I just used a footballer's bicycle kick as reference for rotation. LOL

Since you mentioned about practicing some sword skills, I'd like to get some output so I can research about the materials. But as far as canon tells us, that katana is definitely heavy(Super Dense). I guess we can start with Osmium Boride with parts of Platinum group elements and Rhenium.

New Samarkand Metals does specialize in metallurgy outside of Steel.

Edited by Sneaky B, 09 August 2012 - 07:52 PM.

[Bishop Steiner]

Sneaky B, on 09 August 2012 - 07:48 PM, said:

Well, I wasn't sure myself how fast the blade would swing because No-Dachi are equipped with triple strength myomer. I just used a footballer's bicycle kick as reference for rotation. LOL

Since you mentioned about practicing some sword skills, I'd like to get some output so I can research about the materials. But as far as canon tells us, that katana is definitely heavy(Super Dense). I guess we can start with Osmium Boride with parts of Platinum group elements and Rhenium.

New Samarkand Metals does specialize in metallurgy outside of Steel.

Very true.

Oh, one other thing that needs factored into your force equation.

SURFACE AREA.

The .50 BMG is putting all of it's force (which also does not count sectional density) into a 1/2 surface area. The force from the Katana strike will be across a MUCH broader area, which will significantly reduce it's actual penetration.

Big thing is, a Mech sword is still a club, not really a true "edged" weapon. It is a beveled club, (sorry I just canoot buy the mech vibro sword stuff, canon or no, it's pure Boolshite.). And think, whereas an Asian blade usually was razor sharp, European blades were not, at least not until the Renaissance period. Why? If you take a thin, sharp blade and bash a pig iron breast plate, all you do is dull, flatten or break the edge. The main reason that polearms, picks, hammers and axes were used is they were much better at shearing through heavy armor. Look even at typical medieval swords from your typical broad sword to a claymore like William Wallace used... they were not very sharp, actually. More like a beveled edge to help maximize force to surface area, but staying thick and heavy enough for mass to help, and to avoid breakage.

As for the Metallurgy, the big thing is, that the requirements for a human sized blade, and a mech sized blade are astronomically different, BECAUSE of the mass and size involved, and the armor. Oy. Where's Einstein when you need him?

[Sneaky B]

All right, I ran some numbers again.

benchmark armor target

8 armor points = 1.00 ton
steel mass = 500.00 kg
steel density = 8.05 g/cm³
steel volume = 62,111.80 cm³
Steel dimensions = 111.46 cm x 111.46 cm x 5.00 cm
steel modulus of elasticity = 200 GPa ~ 300 GPa

CBN mass = 500.00 kg
CBN density = 3.45 g/cm³
CBN volume = 144,927.54 cm³
CBN dimensions = 111.46 cm x 111.46 cm x 11.67 cm
CBN modulus of elasticity = 706 GPa ~ 1059 GPa

~~~~~~~~~~~~

katana damage = 8 points of armor
katana total force = 659,730 N @ 219.91 m/s² for 3 ton blade
katana total force = 796,685 N @ 219.91 m/s² for 3.5 ton blade
katana tip pressure = 1,183,796,859 Pa ~ 1.18 GPa @ 5 mm thick
katana tip pressure = 263 GPa @ 2.25 μm thick
katana tip pressure = 300 GPa @ 1.97 μm thick

The katana is made of Platinum group borides. Osmium Boride alone has a bulk modulus of 395 GPa so it could be inferred that the blade will be able to retain sharpness at 2 micrometers even at very high pressure if alloyed and sandwiched into a composite. As for the spine, it should be made of amorphous metallic glass of similar composition so it can withstand stress.

Against the 3 ton katana blade, the benchmark armor's 5 cm thick steel plate would bend 6.60 cm. Meanwhile, the 11.67 cm thick Cubic Boron Nitride Layer will bend 8.01 mm.

Against the katana's full 3.5 ton mass, the benchmark armor's 5 cm thick plate would bend 7.70 cm. Meanwhile, the 11.67 cm thick Cubic Boron Nitride layer will bend 9.35 mm which is almost a centimeter.

Edited by Sneaky B, 14 August 2012 - 05:50 AM.

[Sneaky B]

As for metallic glass, refer to this article: linkage

[Archerko]

Sneaky B, on 14 August 2012 - 05:34 AM, said:

All right, I ran some numbers again.

Owwie~!

[Bishop Steiner]

Sneaky B, on 14 August 2012 - 05:34 AM, said:

All right, I ran some numbers again.

benchmark armor target

8 armor points = 1.00 ton
steel mass = 500.00 kg
steel density = 8.05 g/cm³
steel volume = 62,111.80 cm³
Steel dimensions = 111.46 cm x 111.46 cm x 5.00 cm
steel modulus of elasticity = 200 GPa ~ 300 GPa

CBN mass = 500.00 kg
CBN density = 3.45 g/cm³
CBN volume = 144,927.54 cm³
CBN dimensions = 111.46 cm x 111.46 cm x 11.67 cm
CBN modulus of elasticity = 706 GPa ~ 1059 GPa

~~~~~~~~~~~~

katana damage = 8 points of armor
katana total force = 659,730 N @ 219.91 m/s² for 3 ton blade
katana total force = 796,685 N @ 219.91 m/s² for 3.5 ton blade
katana tip pressure = 1,183,796,859 Pa ~ 1.18 GPa @ 5 mm thick
katana tip pressure = 263 GPa @ 2.25 μm thick
katana tip pressure = 300 GPa @ 1.97 μm thick

The katana is made of Platinum group borides. Osmium Boride alone has a bulk modulus of 395 GPa so it could be inferred that the blade will be able to retain sharpness at 2 micrometers even at very high pressure if alloyed and sandwiched into a composite. As for the spine, it should be made of amorphous metallic glass of similar composition so it can withstand stress.

Against the 3 ton katana blade, the benchmark armor's 5 cm thick steel plate would bend 6.60 cm. Meanwhile, the 11.67 cm thick Cubic Boron Nitride Layer will bend 8.01 mm.

Against the katana's full 3.5 ton mass, the benchmark armor's 5 cm thick plate would bend 7.70 cm. Meanwhile, the 11.67 cm thick Cubic Boron Nitride layer will bend 9.35 mm which is almost a centimeter.

benchmark armor? 8pts? Dunno if you are referring to Battletech armor, but that's 16pts per ton, and in MWO, it's 32 pts per ton.
And I am still curious about the mathematics when actual contact area is figured in, since you can have all the same "measurables" on a blade that is 6 meters long, or a batchet @ 1.5 meters, which will signifigantly increase the energy transfer. (AKA, a sword, no matter how high tech, is an inefficient weapon vs heavy armor, especially since all the same tech can be applied to an axe or hammer or club much more efficiently. Plus.. which unlucky tech gets to sharpen it between missions?

[Sneaky B]

I was experimenting with SSW and apparently 8 points was considered a ton. (LOL?) If it's 16 points then you just made my work a hell lot easier considering the blade will indeed have full penetration on a half ton armor since the thickness would be halved.

Regarding the mathematics behind it, I used the pressure formula which is equal to force divided by contact area. The full blade of the katana doesn't necessarily have to be included in the contact area since the blade is curved and slams to 8 points of armor. As for the bend, I used Young's Modulus. Notice how I used bend instead of cut

That is why I'm just presenting the numbers so I can get inputs

How sharp do you reckon is just right?

And yes, internet giant robots is serious business...

Edited by Sneaky B, 14 August 2012 - 11:30 PM.

[The Basilisk]

Since espezialy the Sword lance etc Mechs are some of the greatest missdevelopments in Battletech history, it doesn't matter how this Mech looks as long as it is gone and stays gone.

[Bishop Steiner]

The Basilisk, on 14 August 2012 - 11:29 PM, said:

Since espezialy the Sword lance etc Mechs are some of the greatest missdevelopments in Battletech history, it doesn't matter how this Mech looks as long as it is gone and stays gone.

I had always considered the Draconis Combine Sourcebook, with the No-Dachi, to be the point that Battletech officially jumped the shark.The glut of hand weapons in Solaris the Reaches, and tehn Dark Age were just to make sure everyone got the point that Battletech had given up on western/industrializing sci-fi and was going all in on the Power Ranger/ Dragon Ball pew-pew camp.

The Rationalization behind the sword and MRMs and such were beyond idiotic, and the later inclusion of claws, lances, and vibro-mech blades .... bad. Just bad. But sadly canon bad. Tis a reason why sometimes it's OK to hit "re-set". No amount of magic metal makes a giant, thin sharp edge a working innovation against reinforced latticed diamond weaved ablative armor. Sharp means thin, and thin will blunt and dull and break. Cause the same techused to make the magic metal in the sword works equally to make magic armor (It's why Wolverine with his pew-pew badazz claws of adamantium counld not damage Ultron, or Captain America's shield, which also contained adamantium (in comic, not movie canon))

Need proof? Take thin whippy sword (such as a beautiful Katana) and go bash a suit of gothic plate armor with it. Armor will dent and ding, blade will flatten and dull, and eventually break. Suit of armor will look like it needs to be ironed. But hey, it LOOKS whiz bang cool, right?
And it ain't like one can get too into "reality" with any sci-fi, even though Battletech for a game made by non engineers, did at least try, initially. (BTW, for those who used the argument.. "teh mechs name is teh No-dachi, so it haz sword!", ummmm there is also the Katana, with NO melee weapon, the Blackjack also (look up what a black jack is), along with the Hammer, and hey the Broadsword class dropship doesn't whiz around firing swords at people, nor do you see the Crossbow, Daikyu or Longbow using actual bows.... hey.. there's a thought! Mech archery! GENIUS!!!!!!!)

So yeah.

Cool math, but emmmm, not really buying it. Also Mech armor is a heck of a lot thicker than 5cm, just sayin. And it ain't made of steel. http://www.sarna.net...hs_%26_Vehicles Not exactly sure how to bench mark that, and I would say that 16 pts vs 8, doesn't mean thinner armor, but that it just doubled it's density on you, but I am no engineer.

[Sneaky B]

But then we're dealing with composite so it's reasonable to defeat each layer represented by 50:50 steel and BCN. Heck, it's 17 cm worth of armor in total. My mistake for not making that clear :S

Of course, the ratio may vary and I could simply push the ablative ceramics to insane levels but I have to factor in field repairs so it also needed some reasonable amount of steel as described in that article (which I already read even before making the calculations).

What I mean on halving the armor thickness, I mean that for the same amount of points, there is less mass and therefore volume provided the density remains constant for the materials because as you said, 16 points is a ton and 8 is... well half. And 8 points is the damage dealt by a 3.5 ton melee weapon.

Then again, we have no clear data how 31st century imaginary weapons systems work.

In retrospect, the weapon now has more armor to chew on so yeah, I will have to consider the blade tip thickness between 5mm and 2mm. I guess 2 micrometer is pushing it

Regarding clubs and blunt weapons, if compared to sword of equal mass actually performs less in terms of pressure because of broader contact area. Like I said, pressure=mass divided by area. Against a lighter sword however, it makes up for momentum.

As final thought, I could have redesigned safer mechs instead of controversial ones but I don't care if four people want my head on a pike right now. Somebody has to do it

Edited by Sneaky B, 15 August 2012 - 06:15 AM.

[Bishop Steiner]

Sneaky B, on 15 August 2012 - 05:57 AM, said:

But then we're dealing with composite so it's reasonable to defeat each layer represented by 50:50 steel and BCN. Heck, it's 17 cm worth of armor in total. My mistake for not making that clear :S

Of course, the ratio may vary and I could simply push the ablative ceramics to insane levels but I have to factor in field repairs so it also needed some reasonable amount of steel as described in that article (which I already read even before making the calculations).

What I mean on halving the armor thickness, I mean that for the same amount of points, there is less mass and therefore volume provided the density remains constant for the materials because as you said, 16 points is a ton and 8 is... well half. And 8 points is the damage dealt by a 3.5 ton melee weapon.

Then again, we have no clear data how 31st century imaginary weapons systems work.

In retrospect, the weapon now has more armor to chew on so yeah, I will have to consider the blade tip thickness between 5mm and 2mm. I guess 2 micrometer is pushing it

Regarding clubs and blunt weapons, if compared to sword of equal mass actually performs less in terms of pressure because of broader contact area. Like I said, pressure=mass divided by area. Against a lighter sword however, it makes up for momentum.

As final thought, I could have redesigned safer mechs instead of controversial ones but I don't care if four people want my head on a pike right now. Somebody has to do it

And I love it that way. Heck I am mostly playing devils advocate.

But as you mention defeating each layer, did your equation factor the inertia loss to each subsequent layer, as the bottome layer would not be subjected to the same force as the top, naturally.

And equal mass between club and sword is true, though again the thicker item will have much better longevity. BUT, a club of equal length would actually outmass the sword by many factors. Whereas equal mass, the club will actually be MUCH shorter than the blade. Also, as an "Odd" note, ever see the performance difference on the Celtic Burda Club, or a Spartan's Hoplon did compared to pretty much ANY sword? Both created force margins all out of whack with what one would expect.

All because the Mass is centered in a much more compact area, whereas the blade, while thin, is still very long (and thus maintains inertia/momentum much more poorly) (the last minute shoes it nicely)

cool stuff.

[Sneaky B]

Yip, you have to factor in the elastic potential energy of the first layer which is the steel plate then subsequently use the remaining force for the CBN layer which is ridiculously stiff :S

But on retrospect, If I used the 1 full rotation per second swing speed, there is no way the katana will ever dream of even bending, even by a millimeter, the CBN layer given that steel is a ductile and tough material. It really has to make up for velocity >.>

(Man, I'm such a nerd T_T)

Edited by Sneaky B, 15 August 2012 - 10:15 AM.

[Sneaky B]

After much deliberation, here are the weapons.


First weapon is the Lyran hatchet. Considered crude by the Draconis Combine. Upon the introduction of Triple Strength Myomer to the Combine, the hatchet was chosen as an interim weapon system. It was redesigned to resemble the Gunbai to make the barbaric weapon tolerable(2nd weapon).

Other weapon systems were tested in conjunction with TMS to determine its limits and for research on high density materials. One such weapon was the Tetsubo(3rd weapon). Test pilots however, complained about its unwieldiness despite its massive damage potential.

Designers at New Samarkand Metals soon rolled out its "katana" (4th weapon). Despite its semblance to its antiqued origins, it is by no means katana but more of a machax thanks to its 1 ton kissaki. Since mech wrists cannot swivel, developers opted to sweep forward the weapon. At first, the weapon was well received by the wide eyed Draconis warriors.

Over time, the "katana's" shortcomings became more apparent. It was significantly more expensive to make because of its materials. The "katana" was also unable to fully utilize its mass because of the location of its center mass. An alternative was sought. New Samarkand Metals used their invaluable experience with metallurgy and opted to replace the "unused" blade surface with a shaft. Thus, the Naginata (last weapon) was born. It was best described by its developers as a kukri on a stick. Because of its advantages, it quickly replaced the Katana as the standard melee weapon system.

Edited by Sneaky B, 16 August 2012 - 11:56 AM.

[Imagine Dragons]

You made a guitar for a giant mech meele weapon?

[Bishop Steiner]

Sneaky B, on 15 August 2012 - 10:09 AM, said:

Yip, you have to factor in the elastic potential energy of the first layer which is the steel plate then subsequently use the remaining force for the CBN layer which is ridiculously stiff :S

But on retrospect, If I used the 1 full rotation per second swing speed, there is no way the katana will ever dream of even bending, even by a millimeter, the CBN layer given that steel is a ductile and tough material. It really has to make up for velocity >.>

(Man, I'm such a nerd T_T)

I'm just a diffrent sort of nerd, lol. Am I reading it right, that you concede that realistically (especially considering the NON-Dragon Ball z refelx speed of Btech Mechs) that the sowrd would NOT penetrate? Or was I getting the result backwards about the bend/effects withthe Katana? (Not that it truly matters, since of course, this IS sci-fi, and it works (by whatever magic means) in canon, lol)

[Bishop Steiner]

Sneaky B, on 16 August 2012 - 11:53 AM, said:

After much deliberation, here are the weapons.


First weapon is the Lyran hatchet. Considered crude by the Draconis Combine. Upon the introduction of Triple Strength Myomer to the Combine, the hatchet was chosen as an interim weapon system. It was redesigned to resemble the Gunbai to make the barbaric weapon tolerable(2nd weapon).

Other weapon systems were tested in conjunction with TMS to determine its limits and for research on high density materials. One such weapon was the Tetsubo(3rd weapon). Test pilots however, complained about its unwieldiness despite its massive damage potential.

Designers at New Samarkand Metals soon rolled out its "katana" (4th weapon). Despite its semblance to its antiqued origins, it is by no means katana but more of a machax thanks to its 1 ton kissaki. Since mech wrists cannot swivel, developers opted to sweep forward the weapon. At first, the weapon was well received by the wide eyed Draconis warriors.

Over time, the "katana's" shortcomings became more apparent. It was significantly more expensive to make because of its materials. The "katana" was also unable to fully utilize its mass because of the location of its center mass. An alternative was sought. New Samarkand Metals used their invaluable experience with metallurgy and opted to replace the "unused" blade surface with a shaft. Thus, the Naginata (last weapon) was born. It was best described by its developers as a kukri on a stick. Because of its advantages, it quickly replaced the Katana as the standard melee weapon system.

Now this is a post I can heartily endorse! It gives a nod to the canon, yet acknowledges the silliness of it (and a military beauracracy making a white elephant design is VERY BELIEVABLE! Just ask the number of soldiers chafing at the 5.56 and 9mm NATO standards to this day.. or the fiasco that is the Marine Corps OSPREY). And then the eventual solution (probably conjured up initially by a line level technician somewhere, sorta like the 6.8 SPC started life thanks to the initiative of Steve Holland (5th SFG (A)) and Cris Murray of the U.S. Army Marksmanship Unit, and of course, the Wiki articles leave that out and makes it sound like it was a Remington initiative.

Still, yeah it's a little clumsy, but gimme my tetsubo! (100 ton mech, plus TSM plus tetsubo war club means 5 pts per ton, doubled, according to the old Maximum Tech rules (though with a "to-hit" penalty of 2 pts, I think?) so 20x2..... doubled again when the TSM activate for an 80 pt THWOCK!!!!! to the punch location table!

[Archerko]

Physical weapons hit on the general table, not the punch table.