tinman Posted November 7, 2005 Author Report Share Posted November 7, 2005 Re: A question to the physics-minded... I wound up just going with a new round for an otherwise conventional 25mm cannon. It became a 3d6 double Penetrating RKA, which was enough to annoy the PC's and maybe warn them that worse could follow if they keep pushing their luck. This way I can keep all of the more exotic ideas from this thread in reserve for escalation Quote Link to comment Share on other sites More sharing options...
gewing Posted November 7, 2005 Report Share Posted November 7, 2005 Re: A question to the physics-minded... Humm, If I recall my physics class correctly, the superheated air would have more resistance that normal air. It is in the couple of nanoseconds between the time the laser shuts down and the air moves back in tot he tunnel (probably with a thunderclap) that you would have the reduced friction. Power requirements, probably something equlevent to a lighting bolt to target the thing. What about giving the projectiles a super-aerodynamic shape or a super-teflon frictionless coating? Or both, and making those Sx for double armor piercing? If the laser is that powerful, just use IT! At a lesser power you can theoretically ionize the air and send a current through it, as a NASTY TASER type weapon. It should be able to fry many electronics too. An advanced APFSDS as used in the newest tank guns only lose between 50 and 75 m/s velocity for every KILOMETER travelled. Is that enough? If not, maybe a rocket booster to maintain velocity? There is no reason a projectile in 5 years or so would not be even better, maybe 35 m/s/km? NOt a hell of a lot of change, at that point! And if you fire it at gauss gun velocities, trajectory is nearly meaningless. Or use small guided missiles like the Spike minimissile developed by the Naval Weapons station. iirc 4.4 lb missile, 2 mile range, 2 lb Explosively formed penetrator warhead. launcher is only another 3 lbs or so. Quote Link to comment Share on other sites More sharing options...
gewing Posted November 7, 2005 Report Share Posted November 7, 2005 Re: A question to the physics-minded... If you mean the Shival...I'm not sure thats how it is spelled ...it is a rocket powered super-caitating torpedo...but the US, in panic mode that somebody has a technology they didn't even think off is working on the same tech, and what little I've seen they are also working on , or have developed super cavitating bullets, so a underwater auto-cannon is either possable or in production...I am slightly sure that the 20mm rounds were at least theoreticly capable of trans sonic speeds underwater. I don't see why the principle could not be applied to the atmosphere as well...maybe a small ionizing emitter and a small magnetic bubble and you get hypersonic cannon rounds...??? There is a project to build a cannon and fire control system that can mount on a helicopter and locate, target, then destroy underwater mines. They developed a supercavitating version of a 25mm iirc cannon round (might have been 30mm) that is still moving something like 3000 fps up to 80 METERS under water. That is pretty impressive. Quote Link to comment Share on other sites More sharing options...
gewing Posted November 7, 2005 Report Share Posted November 7, 2005 Re: A question to the physics-minded... This is too exotic, but what the heck. You can trap particles with laser tweezers. You need two beams (or a tight focus) to trap the particle in all three dimensions, but you can easily trap a particle in two dimensions. Now, make this particle reflective and you have a pellet that moves in the laser beam. So, we make a hollow glass pellet with a reflective coating. Yes, it's very small, but we're going to give it a big payload. Now put four charges on the outside of the pellet in a tetrahedral pattern. Put a small amount of identically charged antimatter inside the pellet (you did put the pellet under vacuum first, right?). Hit the target with the laser beam. Release the pellet into the beam. The glass pellet hits, breaks, falls down, goes BOOM! If you want to see where you're targeting, use visible light. If you want invisible power effects, infrared and ultraviolet lasers are also available. Whatever you do, do not drop your ammo The Willy guns in the "sten" books used a material called AM2 in glass beads. I want one. Quote Link to comment Share on other sites More sharing options...
gewing Posted November 7, 2005 Report Share Posted November 7, 2005 Re: A question to the physics-minded... 1d6 RKA, double penetraiting. I'd go with a bullet, 9mm or whatever the standard issue police sidearm is in your campagine city. Teflon coated (first layer of penetration) sabot rounds (I think that's the term I want). Copper-jacketed lead rounds containing an explosive charge that will explode on impact, driving small needle of hard yet dense metal forward (second layer of penetration). This is going to draw blood on any character without double-hardened PD, teach them that agents are not just an annoyance, yet is not a character killer. A tandem shaped charge warhead should do fine for that. First one punches a hole, second makes it DEEPER. Or, First round detonates with standoff. Second is an explosive penetrator that goes down the hole made by the first! (look up BROACH bunker buster) Old fashioned "squash head" projectiles should work against some forms of defenses. they were quite nasty until tanks started using spaced armor. Thin shelled Plastic explosive warhead hits armor, jacket ruptures, plastic Exp. "squashes" int a poultice on the side of the armor. Then the base fuse detonates, and the shock waves flake off a piece of the inside of the armor (think of a window hit by a bb or rock) but the piece is moving several hundred meters per second, iirc. Plate mail? heh heh heh. Quote Link to comment Share on other sites More sharing options...
Sean Waters Posted November 7, 2005 Report Share Posted November 7, 2005 Re: A question to the physics-minded... The biggest problems with projectiles is twofold in a planetary atmosphere: 1. air resistance and 2. gravity OK: air resistance. You can make it as aerodynamic as you like, we are still going to have problems. Possible solutions include an abrasion layer on the projectile - basically air friction tears off the outer coating so that the abrasion layer so the projectile itself is not solowed so much; some sort of vacuum tube, which might be accomplished by a low powered force field; some fort of force field around the projectile itself, creating a frictionless surface. Gravity: well, some sort of antigrav device IN the projectile, rocket power and fins to keep it in the air, firing the projectile along a graviton beam which briefly neutralises (very) local gravity. Depending on the tech level, the favourite has to be a teleportation gun: weapon itself doesn't have a hole at the end of the barrel, just a hollow tube in vacuum with a one way teleport gate at the other end to the projectile: bullet accelerated to high speed, then gated to the immediate proximity of the target, or, for the really cocky sniper, INSIDE the target....with the right targetting devices, you could even fire THROUGH solid matter (basically we are just buying this as indirect, or for TP INSIDE a NND/Does BODY (not through TP hardened defences)....mind you we are getting pretty sci-fi now, or so they would have you believe.... Quote Link to comment Share on other sites More sharing options...
Jaxom Posted November 7, 2005 Report Share Posted November 7, 2005 Re: A question to the physics-minded... To elaborate, my PC's have been exhibiting more of a "your puny bullets cannot harm us, we are gods among insects" kind of attitude lately. I need to make sure the authorities have a way of making them rethink their dismissive attitudes. Ahhh! We reach the crux of the issue. So... Tell me more about these PCs. I've got a number of detailed ideas depending on backgrounds and hero-types. Feel free to PM if you don't want to post here. My immediate thought is that bullets are the wrong idea. There are all sorts of fun ideas around disabling them. Long-term EGO drain is a great toy and can be as simple as "suceptibility to Three Stooges reruns" or more evil ranging from sonic delivery to gas delivery. Nothing like having a bunch of guys with ear plug walk in and pick you up as you pass out to humble you a bit. EGO-based entangle? Something like Tear Gas (which was recently discussed in a different thread) which is effectively a high-penalty Change Environment NND with some simple but uncommon defense (which none of the players have, of course). Every player should fear the sentence, "As you are passing out a group of shadows approaches you (you're too blurred to tell how many). You feel them hoisting you onto something as you finally lose consciousness." Quote Link to comment Share on other sites More sharing options...
Sean Waters Posted November 7, 2005 Report Share Posted November 7, 2005 Re: A question to the physics-minded... Nah, paranoia training: basically group of agents range up in front of heroes, spray them with machine gun fire. Bounces. THEN they change clips, and spray again. These bullets don't bounce off: they squash and stick to the hero, or their armour, or their force field, and SLOWLY start to sink in - through their skin/armour/force field. The bullets don't actually have to DO anything except sink in: the players will be so paranoid it is going to do something horrendous to them they will be spending somewhere between the next turn and the next four gaming sessions trying to work out what HAS been done to them And they won't be so cocky about bullets.... Quote Link to comment Share on other sites More sharing options...
Jaxom Posted November 7, 2005 Report Share Posted November 7, 2005 Re: A question to the physics-minded... The bullets don't actually have to DO anyhting except sink in: the players will be so paranoid it is going to do something horrendous tot hem they will be spending somewhere between the next turn and the sext four gaming sessions trying to work out what HAS been done to them Niiiiiiice. I like it. Sadly, I get to spread some rep around before you get rewarded for it. Quote Link to comment Share on other sites More sharing options...
tinman Posted November 7, 2005 Author Report Share Posted November 7, 2005 Re: A question to the physics-minded... Niiiiiiice. I like it. Sadly' date=' I get to spread some rep around before you get rewarded for it.[/quote'] I got him Quote Link to comment Share on other sites More sharing options...
tinman Posted November 7, 2005 Author Report Share Posted November 7, 2005 Re: A question to the physics-minded... Ahhh! We reach the crux of the issue. So... Tell me more about these PCs. I've got a number of detailed ideas depending on backgrounds and hero-types. Feel free to PM if you don't want to post here. My immediate thought is that bullets are the wrong idea. There are all sorts of fun ideas around disabling them. Long-term EGO drain is a great toy and can be as simple as "suceptibility to Three Stooges reruns" or more evil ranging from sonic delivery to gas delivery. Nothing like having a bunch of guys with ear plug walk in and pick you up as you pass out to humble you a bit. EGO-based entangle? Something like Tear Gas (which was recently discussed in a different thread) which is effectively a high-penalty Change Environment NND with some simple but uncommon defense (which none of the players have, of course). Every player should fear the sentence, "As you are passing out a group of shadows approaches you (you're too blurred to tell how many). You feel them hoisting you onto something as you finally lose consciousness." I will actually PM you later today and give you some details. Quote Link to comment Share on other sites More sharing options...
tinman Posted November 7, 2005 Author Report Share Posted November 7, 2005 Re: A question to the physics-minded... If anyone is interested, the web site for the campaign is at http://142.165.131.108 Quote Link to comment Share on other sites More sharing options...
Sean Waters Posted November 7, 2005 Report Share Posted November 7, 2005 Re: A question to the physics-minded... If anyone is interested' date=' the web site for the campaign is at http://142.165.131.108[/quote'] Wow. That's more detail than I've ever written down for all the games I've ever run, ever. Really interesting background. Very impressed. Sean Waters Quote Link to comment Share on other sites More sharing options...
tinman Posted November 7, 2005 Author Report Share Posted November 7, 2005 Re: A question to the physics-minded... Wow. That's more detail than I've ever written down for all the games I've ever run, ever. Really interesting background. Very impressed. Sean Waters Thanks Quote Link to comment Share on other sites More sharing options...
Pogo Posted November 7, 2005 Report Share Posted November 7, 2005 Re: A question to the physics-minded... If the laser is that powerful, just use IT! There are a few problems with laser weapons. First, the damage is usually very localized. Admittedly a quarter inch diameter hole through you will make life suck, but now we get to the second problem. Lasers produce plasmas when they hit. Zap a target with a powerful laser and all sorts of charged particles get kicked out into the beam. The more powerful the laser, the more concentrated the cloud of particles. Unfortunately plasmas scatter photons, so the power reaching the target goes down quickly with time. The bits being blown off break the beam. You can pulse the laser to make this less of an issue, but you need a low duty cycle for it to work. We wants to deliver pain with a high duty cycle At a lesser power you can theoretically ionize the air and send a current through it, as a NASTY TASER type weapon. It should be able to fry many electronics too. Unfortunately if there's enough ionization to transmit the current, there's probably enough dissapation to keep the laser from having a good range. Hmmm, I might be wrong here. If the laser flux is significant only near the focus, then you can sweep out a path for the current to follow. Hey, that could make for a cool looking autofire. The current arcs from the device to character A to character B to . . . . Quote Link to comment Share on other sites More sharing options...
tinman Posted November 7, 2005 Author Report Share Posted November 7, 2005 Re: A question to the physics-minded... There are a few problems with laser weapons. First, the damage is usually very localized. Admittedly a quarter inch diameter hole through you will make life suck, but now we get to the second problem. Lasers produce plasmas when they hit. Zap a target with a powerful laser and all sorts of charged particles get kicked out into the beam. The more powerful the laser, the more concentrated the cloud of particles. Unfortunately plasmas scatter photons, so the power reaching the target goes down quickly with time. The bits being blown off break the beam. You can pulse the laser to make this less of an issue, but you need a low duty cycle for it to work. We wants to deliver pain with a high duty cycle Unfortunately if there's enough ionization to transmit the current, there's probably enough dissapation to keep the laser from having a good range. Hmmm, I might be wrong here. If the laser flux is significant only near the focus, then you can sweep out a path for the current to follow. Hey, that could make for a cool looking autofire. The current arcs from the device to character A to character B to . . . . I am completely in awe of the high-tech-fu demonstrated in this entire thread. Quote Link to comment Share on other sites More sharing options...
EverKnight Posted November 7, 2005 Report Share Posted November 7, 2005 Re: A question to the physics-minded... Wow. That's more detail than I've ever written down for all the games I've ever run, ever. Really interesting background. Very impressed. Sean Waters I second that wow and raise a wowee. I admit to being hooked reading the background and wondering if the world is going to tear itself apart. I was wondering if you have an organisation of metahumans devoted to helping those that have recently discovered themselves to be metahumans? Quote Link to comment Share on other sites More sharing options...
prestidigitator Posted November 8, 2005 Report Share Posted November 8, 2005 Re: A question to the physics-minded... Unfortunately if there's enough ionization to transmit the current' date=' there's probably enough dissapation to keep the laser from having a good range. Hmmm, I might be wrong here. If the laser flux is significant only near the focus, then you can sweep out a path for the current to follow. Hey, that could make for a cool looking autofire. The current arcs from the device to character A to character B to . . . .[/quote'] Well, one solution is to continuously focus the beam, starting at an infinite focal point and sweeping in to a reasonable, "minimum range." Then it will have a limited range because there will be a distance beyond which the focal point moves to quickly to deliver enough energy to ionize the air. Of course lasers will always have a limited range anyway because of defraction. Higher frequencies are required for longer ranges, and there will always be a limit. Quote Link to comment Share on other sites More sharing options...
tinman Posted November 8, 2005 Author Report Share Posted November 8, 2005 Re: A question to the physics-minded... I second that wow and raise a wowee. I admit to being hooked reading the background and wondering if the world is going to tear itself apart. Thanks very much for the high praise. I wonder anew each session if the world will tear itself apart I was wondering if you have an organisation of metahumans devoted to helping those that have recently discovered themselves to be metahumans? There are a few, but they are isolated and under extreme scrutiny. For a while there was an "underground railroad" of sorts, but the destination got bombed out of existence. Right now there is new enclave slowly solidifying on the moon, but getting there is tricky for most. To be honest I pretty much expected the PC's to take a leading role in something like this, but they haven't. Quote Link to comment Share on other sites More sharing options...
gewing Posted November 8, 2005 Report Share Posted November 8, 2005 Re: A question to the physics-minded... There are a few problems with laser weapons. First, the damage is usually very localized. Admittedly a quarter inch diameter hole through you will make life suck, but now we get to the second problem. Lasers produce plasmas when they hit. Zap a target with a powerful laser and all sorts of charged particles get kicked out into the beam. The more powerful the laser, the more concentrated the cloud of particles. Unfortunately plasmas scatter photons, so the power reaching the target goes down quickly with time. The bits being blown off break the beam. You can pulse the laser to make this less of an issue, but you need a low duty cycle for it to work. We wants to deliver pain with a high duty cycle Unfortunately if there's enough ionization to transmit the current, there's probably enough dissapation to keep the laser from having a good range. Hmmm, I might be wrong here. If the laser flux is significant only near the focus, then you can sweep out a path for the current to follow. Hey, that could make for a cool looking autofire. The current arcs from the device to character A to character B to . . . . the bits being broken off by a weapon level laser are the thing IMO that everyone forgets... A fairly low power continous or rapid pulse laser MIGHT be able to do the "flashlight laser" bit, but if you hit a target with a pulse of laser energy at high enough power, it is iirc not that different from a stick of dynamite being detonated in contact. This was one of the damage mechanisms the Star Wars laser weapons were aiming for, iirc. they wanted about 10 megawatts, with a beam diameter that was at least 1.5 meters. The number "10 meters" sticks in my head... As they were deciding that mirrors that size might be too difficult, iirc they looked at a cluster of 7 or so lasers firing along roughl parallelly and at the same time, to get a large area for ease of hitting, but still be workable. If the pulse is short and high energy enough, it might act similarly to the squash head rounds mentioned before... Though unless you put ludicrous levels of energy into a tiny beam or use an xray laser or graser, laser weapons afaik are NOT great anti armor weapons. They might strip everything off the OUTSIDE of the armor... Quote Link to comment Share on other sites More sharing options...
Pogo Posted November 8, 2005 Report Share Posted November 8, 2005 Re: A question to the physics-minded... Well, one solution is to continuously focus the beam, starting at an infinite focal point and sweeping in to a reasonable, "minimum range." Then it will have a limited range because there will be a distance beyond which the focal point moves to quickly to deliver enough energy to ionize the air. That works. You have to sweep quickly so the charge doesn't dissipate (they likes to do that), but it is doable for some very elastic values of doable. Of course lasers will always have a limited range anyway because of defraction. Higher frequencies are required for longer ranges, and there will always be a limit. Well, you can get around that if you assume the air density is uniform -- if tinman's world doesn't have parking lots, roads, or driveways, this might work -- and you have a big honking laser. There's a phenomenon called self-focusing. If the beam is intense enough, it can change the index of refraction of the medium it is passing through. Usually this is done in a glass. The middle of the beam is more intense than the edges, so the index of refraction is greater there. This acts as a lens, focusing the light inwards. The laser exceeds the dielectric breakdown for the material and you get these neat tracks in the material. If you balance the beam energy just right you can counter diffraction, giving close to unlimited range. Of course to drive air into this nonlinear region takes a lot of photons, and you may hit ionization limits first. Quote Link to comment Share on other sites More sharing options...
Pogo Posted November 8, 2005 Report Share Posted November 8, 2005 Re: A question to the physics-minded... [My coverage of some problems with laser weapons deleted ] I am completely in awe of the high-tech-fu demonstrated in this entire thread. Coming from the person who created this web site: If anyone is interested, the web site for the campaign is at http://142.165.131.108 that's quite a compliment. I should be bowing to you Besides, its been a while since I've gotten to use the destructive parts of physics. This is fun. Quote Link to comment Share on other sites More sharing options...
tinman Posted November 8, 2005 Author Report Share Posted November 8, 2005 Re: A question to the physics-minded... [My coverage of some problems with laser weapons deleted ] Coming from the person who created this web site: that's quite a compliment. I should be bowing to you Besides, its been a while since I've gotten to use the destructive parts of physics. This is fun. Aww shucks Quote Link to comment Share on other sites More sharing options...
prestidigitator Posted November 8, 2005 Report Share Posted November 8, 2005 Re: A question to the physics-minded... Of course lasers will always have a limited range anyway because of defraction. Higher frequencies are required for longer ranges' date=' and there will always be a limit.[/quote'] Well, you can get around that if you assume the air density is uniform -- if tinman's world doesn't have parking lots, roads, or driveways, this might work -- and you have a big honking laser. There's a phenomenon called self-focusing. If the beam is intense enough, it can change the index of refraction of the medium it is passing through. Usually this is done in a glass. The middle of the beam is more intense than the edges, so the index of refraction is greater there. This acts as a lens, focusing the light inwards. The laser exceeds the dielectric breakdown for the material and you get these neat tracks in the material. If you balance the beam energy just right you can counter diffraction, giving close to unlimited range. Of course to drive air into this nonlinear region takes a lot of photons, and you may hit ionization limits first. Diffraction causes even an initially perfectly columnated beam in a perfect vaccum to spread over distance. There is really nothing you can do about it; no amount of focusing or reflecting will allow you to keep a laser beam completely columnated. That's why power transmission over large distances would require very high-frequency lasers; it isn't merely an atmospheric issue. Quote Link to comment Share on other sites More sharing options...
Zeropoint Posted November 9, 2005 Report Share Posted November 9, 2005 Re: A question to the physics-minded... Minimum beam divergence is governed by a function of the wavelength and aperture diameter (the same effect limits the resolution of telescopes). To get a laser to have a useful degree of focus at a distance requires a large mirror. I don't remember the formula, but poking around a good physics website should get it for you. Zeropoint "The laws of physics are a harsh mistress" -- Bender Quote Link to comment Share on other sites More sharing options...
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