Monofilament Blade

[starblaze]

I have a gadgetering character who uses a monofilament blade as one of her weapons. I have so far had it be an HKA with armor piercing. But I wanted to post so other suggestions as well. Any thoughts?

[Agemegos]

Frankly, I don't think they would work. The edge would hit a crystal or a tough macromolecule and snap. Besides which, like the fine glass pipettes used in getting organelles out of cells, its very likely that such a fine thing could pass right through cell membranes and that they would just reassemble when it had passed. But that's just me.

[Trebuchet]

The classic Larry Niven monofilament blade was a monomolecular chain reinforced with a force field. The only known things that could stop it IIRC was a General Products hull (also a single molecule) or a force field.

I'd build it as a medium sized RKA NND Does Body. Three or four dice should be enough to kill most beings in a single swing; more if you want to get really nasty. For all practical purposes, except the reflection bit, a monofilament blade is equivalent to a light saber, so you might Search for the various threads on building light sabers in this forum.

[Agemegos]

The classic Larry Niven monofilament blade was a monomolecular chain reinforced with a force field. The only known things that could stop it IIRC was a General Products hull (also a single molecule) or a force field.

So how long before we have armour vests woven of monomolecular thread, and with force-field plate inserts?

You have to think your technology through in pre-build, not just let players drag in half-baked ideas from every bit of SF they've ever read or seen. Otherwise you end up with PCs owning some very valuable patents.

[tgrandjean]

*grins* Your usual list of options

1) HKA + AP or AP*2
2) HKA + Penatrating or Pen*2
3) HKA + NND + Does Body
4) HKA + AVLD (force fields, hardening) + Does Body

As always, your choice to any of these is whether or not Str adds damage.
BTW add stretching to any of these options for a mono-whip.

[Curufea]

Standard other sci-fi RPGs only deal with monofilament - because monomolecular doesn't fit into their rules (it's kind of a bit too physics-related for them). I'm wondering if you should treat it as a KA with a transform (person with limbs to person with less limbs etc...)

Anyhow, back when Andromeda was a good series (that would be season 1) it was established that the hull consisted of long chain carbon molecules. Strongest thing you could get (barring whatever Niven's GP hulls were made of), but didn't stop things inside getting shaken about.

Of course, after season 1, they casually tossed any science out the window and trek-erised it (and put in enough HTH to please the Hercules fans - both of them)

[Agemegos]

Any thoughts?

The tensile strength of buckytube is on the order of 100Gpa. The tensile strength of steel is up to 340 MPa. So you see that although monomolecular fibres are very strong, they are by no means unbreakable. 'Only' 300 times as strong as steel.

And a monomolecule is mightily thin. The diameter of a single buckytube is about 0.27 nm. So I estimate its strength as that of a steel wire 10 nanometres thick. A breath would break that.

All in all, I estimate the breaking strain of a single buckytube as 5 trillionths of a newton. That's about a trillionth of a pound force. It isn't going to cut through flesh and armour like a wire through cheese. It is going to be incredibly fragile.

A monofilament blade is not an SF object, it is half-baked techno-babble.

[Curufea]

Hence the Niven monomolecular forcefield, and the Andromedan hull being similar to fibre-glass.

[Agemegos]

Hence the Niven monomolecular forcefield, and the Andromedan hull being similar to fibre-glass.

Just so.

Forcefields I can't speculate about. But monofilament itself won't make a practical weapon, let alone a devastating one. By the time you braid it think enough to stand up to the strain of use, it will be as good for cutting things as surgical silk is.

And as for materials reinforced with or spun from from monomolecular filament, to me they suggest armour rather than knives. I think the 'monofilment knife' is arse-forwards. Think of hardened or doubly-hardened flexible armour rather than armour-piercing or penetrating HKAs.

[Killer Shrike]

I have a gadgetering character who uses a monofilament blade as one of her weapons. I have so far had it be an HKA with armor piercing. But I wanted to post so other suggestions as well. Any thoughts?

Well, for starters I think you mean monomolocular. My shoe string is monofilament, and it's not going to cut anything any time soon.


For a Monomolecular-edged blade on the otherhand, HKA with AP works well, as does NND Does Body (Not vs FF, FW, or hyper-dense physiology), or AVLD Does Body vs Power Defense, or any of a number of other power constructs.


The real question should be does HKA AP cause the effect you deem suitable for a weapon with an edge the width of a molecule? If the answer is yes, then you are set.

[ajackson]

The other question is whether the GM is willing to let you have a given writeup. For example, I wouldn't normally permit AVLD does body. As others have noted, realistic physical descriptions of monomolecular blades imply them not being very useful (another problem is that, even if the blade could survive, most materials are capable of simply resealing after a molecule-sized disruption, so you might cut through things and do no damage).

For genre tropes, it might actually be reasonable to have an HKA where Str doesn't add.

[Brother Jim]

just a thought.

the monomolecular edge cuts through things very easily, and the rest of the "blade" continues the separation of pieces-parts until they permanently separate.


or am i not seeing something ?

[Inu]

just a thought.

the monomolecular edge cuts through things very easily, and the rest of the "blade" continues the separation of pieces-parts until they permanently separate.


or am i not seeing something ?

If you're talking about a blade rather than a whip, yah.

The problem I see here is that edges tend to distort - after a hit or two, it's probably not monomolecular any more.

Suffice to say that the technology required to make monomolecular anything worthwhile (usually, particularly advanced forcefield tech) is probably WELL in advance of where most people are gaming. You could certainly imagine a setting where such things could work, and game there. Trek is possibly a place, as are Niven's books. (I include the latter so that nobody thinks I'm dissing people who play in high-tech settings by mentioning only Trek.) It's probably not appropriate for something like cyberpunk.

The previous paragraph, of course, talks only about harder SF games. If you're soft-serving your sci-fi, go for it.

I'd personally always have forcefields block them, as well as high-tech enough hardened armour. I'd go with the NND construct.

Alternately, you could say that the forcefield required to stabilise the monofilament reduces its cutting power. In that case, go for AP, APx2, PEN, or any combination of the above.

[Agemegos]

the monomolecular edge cuts through things very easily, and the rest of the "blade" continues the separation of pieces-parts until they permanently separate.


or am i not seeing something ?

You seem to be assuming that the monomolecular edge will be unreasonably strong. But it won't. It will only take a few billionths of a pound force to break a monomolecule.

Edges that smash through armour have to be robust. When it comes right down to it you have to deform the armour, and deforming the armour requires force.

Furthermore, if strong long-chain molecules are available for edging knives, there will be an even better use for them in weaving cloth armour or reinforcing composite plates in armour. We use kevlar for armour, not for knife edges. I bet it would be better than kelvar for stopping bullets. So everyone with armour will be wearing it. So a monomolecular knife edge that cut through kevlar like a knife through cheese, even if it worked, which it wouldn't, would be a useless curiosity.

[Agemegos]

Well, for starters I think you mean monomolocular. My shoe string is monofilament, and it's not going to cut anything any time soon.

Yeah, well. At the time I was reading the Niven with the variable sword in it (was it Ringworld? Did Speaker-to-Animals use one in an attempt to hijack the ship?) my father was stitching up people's facial lacertions with monofilament suturing material. Which is to say nylon or silk that had been extruded at the thickness required, and was not spun or braided out of separate filaments. One filament = monofilament, all fair and above board.

But words sometimes have who meanings, and I don't think that we are in desperate danger of confusing nylon monofilament with monomolecular filament, even if they both go by the same name. So let's not bust anyone's chops. Mkay?