 Arrow Design, continued from 'Need help making...' |
  |
 Sep 21 2004, 05:43 PM
Post
#1
|
|||||
|
Great Dragon  Group: Members Posts: 5,889 Joined: 3-August 03 From: A CPI rank 1 country Member No.: 5,222  |
Continuing from here.
I do not question the capability of such broadhead designs to penetrate those, or flesh, or plate mail, but modern (2004) body armor is orders of magnitude tougher than that, and it'll get a whole lot tougher in 60 years. If you're hoping to get the arrow to penetrate any armor, going with a broadhead won't leave any extra space for explosives either -- the blades will have to be kept extremely thin. It would allow for a bit of extra fragments which might come in handy -- for a non-armor piercing variant, a big broadhead would be best to maximize fragmentation. I still maintain that a very sharp point is the way to go if armor penetration is required, and thus the +1 Power of Dikote is a good comparison.
This might work if the explosives are in a cone towards the rear of the arrow and the whole front is filled with easily fragmenting material. If triggered once the head (still preferably pointed) has penetrated the armor, optimally much of the shock wave and fragmentation would pass through that hole. It's a rather risky way of getting the same effect as with a very basic explosive arrow design. If you've already got the arrowhead through armor (a big if), you can probably get most of the arrow through that hole. Once it's up to the fletching in the armor or stopped, set off the tubular explosive charge starting from the rear -- this should prove plenty lethal with an easily fragmenting material for the shaft. |
||||
 |
 
|
||||
|
Sep 21 2004, 05:44 PM
Post
#2
|
|
|
Moving Target Group: Members Posts: 171 Joined: 9-September 04 Member No.: 6,641 |
Since when is dikoting an arrow not enough?
|
|
|
|
|
Sep 21 2004, 05:50 PM
Post
#3
|
|
|
Great Dragon Group: Members Posts: 5,889 Joined: 3-August 03 From: A CPI rank 1 country Member No.: 5,222 |
Since the moment someone wanted an armor piercing arrow that does Deadly base damage. I'd personally rather go with an Assault Cannon with AV ammunition at that point.
|
|
|
|
|
Sep 21 2004, 05:51 PM
Post
#4
|
|
|
Moving Target Group: Members Posts: 171 Joined: 9-September 04 Member No.: 6,641 |
Me too. Dikoted arrows are cannon, and simple rules wise. If you want a projectile weapon which does base deadly damage, dikote a heavy crossbow bolt. 7D, and armor piercing. Le ow.
|
|
|
|
|
Sep 21 2004, 05:58 PM
Post
#5
|
|
|
Target Group: Members Posts: 40 Joined: 16-September 04 From: Paris Member No.: 6,669 |
Actually, in the CC, it became 8S, so it would be a 9D.
Besides, in Sr, bolt are not armor piercing. It can seem logical, but that's not canon. |
|
|
|
|
Sep 21 2004, 06:00 PM
Post
#6
|
|
|
Man In The Machine Group: Dumpshocked Posts: 2,264 Joined: 26-February 02 From: I-495 S Member No.: 1,105 |
Oddly, a broadhead arrow will tear into modren day body armor like butter. Unless its got ceramic plates. Isnt the concept of a troll bow adept scary enough? Do we really need AV arrows? Does that even make sense?
|
|
|
|
|
Sep 21 2004, 06:02 PM
Post
#7
|
|
|
Great Dragon Group: Members Posts: 5,889 Joined: 3-August 03 From: A CPI rank 1 country Member No.: 5,222 |
Stupid me, I read "Barbed Head" as "Broadhead" in CC p. 12. Yeah, you could easily justify all standard arrows getting +1 Power, +1 DL from Dikote.
The Heavy Crossbow with Dikoted bolts is a real killer against unarmored opponents, certainly. Perfect for hunting, I'd imagine. The low power is a bit of a turn-off, even if it goes against the usually-lower Impact. |
|
|
|
|
Sep 21 2004, 06:03 PM
Post
#8
|
|
|
Moving Target Group: Members Posts: 171 Joined: 9-September 04 Member No.: 6,641 |
True, but dikoted arrows fired by a strong archer are lower damage code (S) but higher power.
|
|
|
|
|
Sep 21 2004, 06:04 PM
Post
#9
|
|
|
Running Target Group: Members Posts: 1,408 Joined: 31-January 04 From: Reston VA, USA Member No.: 6,046 |
I agree with everything everyone has said in this thread, and realize that the whole concept of strapping explosives onto arrow heads is more cinematic than realistic.
That said, I'm interested in your (better informed) opinions. What is the theoretical viability of attaching small shaped charges onto the ends of arrows instead of pointed ends. The penetration and damage would both be solely based on the blast (and therefore would be a set value, not varying based on strength), but might(?) get better penetration than an actual piercing arrow. (It would still be more effective to just make them to a grenade launcher instead, but might satisfy some peoples Rambo flashbacks.) What do you think? |
|
|
|
|
Sep 21 2004, 06:15 PM
Post
#10
|
|||
|
Great Dragon Group: Members Posts: 5,889 Joined: 3-August 03 From: A CPI rank 1 country Member No.: 5,222 |
No, and broadheads don't tear into modern body armor like butter. Some armor designs are certainly vulnerable to such attacks, as has been proven by many knife wounds through armor vests. But that should be a thing of the past now that stab and cut protective body armor is becoming more and more common. Getting rid of some armor construction methods and making minor adjustments into projectile-resistant armor eliminates this problem. And that doesn't take into account all the new inventions in the field. We've got the Shear Thickening Liquids that have been discussed several times on this forum, and several other designs to make the armor rigid on impact, at least as far as the projectile is concerned. I've heard a billion rumors about broadhead vs modern body armor, but has someone actually have some proof? I mean, I don't doubt that arrows can penetrate certain types of body armor, I know they can, but I'd really love to see some sort of investigation into how common such armor types are, exactly what sort of penetration we're talking about here, etc. And BTW, metal rifle plates in a kevlar vest are plenty hard enough to stop any arrow fired from a man-portable conventional bow in existance. No need for ceramic plates. |
||
|
|
|
||
|
Sep 21 2004, 06:32 PM
Post
#11
|
|||
|
Great Dragon Group: Members Posts: 5,889 Joined: 3-August 03 From: A CPI rank 1 country Member No.: 5,222 |
The heaviest commonly used arrowhead today is 125 grains (8 grams). That's about Light Sporting Rifle or midway between Light and Heavy pistols in bullet weight. A shaped charge, like any other explosive, would be quite useless at that weight. But then there's Explosive ammunition for Hold-Out Pistols and Assault Rifles, and you could probably make the arrowhead weigh, what, 300-ish grains if you don't mind fucking up the ballistics. So why not? However, I personally think that's covered nicely by the basic EX-Explosive arrowhead. It has better penetration than a Dikoted arrow -- if it only exploded and fragmented all around, how would you explain that? (That's not an actual invitation to think logically about Explosive ammunition or arrowheads, it'll make your brain explode.) |
||
|
|
|
||
|
Sep 21 2004, 06:35 PM
Post
#12
|
|
|
Man In The Machine Group: Dumpshocked Posts: 2,264 Joined: 26-February 02 From: I-495 S Member No.: 1,105 |
Meh, :oops: Im still on the low end. It used to, then the knife proof bit was added. How's that work anyhow?
|
|
|
|
|
Sep 21 2004, 06:42 PM
Post
#13
|
|||
|
Great Dragon Group: Members Posts: 5,889 Joined: 3-August 03 From: A CPI rank 1 country Member No.: 5,222 |
Certainly not all body armor in use now IRL is rated as Stab Resistant -- in fact such armor is a rather small minority. STL and other such advances aren't even in use yet. So if you went out there and started shooting people wearing armor vests with broadhead arrows, you might see penetrations. Give it 10 years, though, and the number of penetrations will drop sharply. Give it 60... |
||
|
|
|
||
|
Sep 22 2004, 01:06 AM
Post
#14
|
|
|
Moving Target Group: Members Posts: 160 Joined: 16-August 03 Member No.: 5,501 |
what 10 years if your layer is good, 60 if he isnt? :grinbig:
|
|
|
|
|
Sep 22 2004, 07:53 AM
Post
#15
|
|
|
Neophyte Runner Group: Members Posts: 2,073 Joined: 23-August 04 Member No.: 6,587 |
You say SR armour is really effective but check out the leather jacket. Real leather provides 2 points of impact armour. This suggests that the impact armours are not all that affective. Light security armour is only twice as good as a leather bike jacket (and as leather turns away such a large portion of the attack impact weapons are very weak). That or they did something strange to the leather.
Edward |
|
|
|
|
Sep 22 2004, 07:57 AM
Post
#16
|
|||
|
Great Dragon Group: Members Posts: 5,889 Joined: 3-August 03 From: A CPI rank 1 country Member No.: 5,222 |
SR leather is maaaaaaaagic, just like the super-angry diamond molecules of Dikote and the magazine on an AVS. For the canon Leather vs Armored Clothing Impact Armor figures to make sense, you'd have to assume that 2060s body armor is manufactured out of materials which unravel themselves or melt to goo whenever hit by a very sharp point or anything with more than 60 grams of mass behind it. Perhaps when they made that table they were thinking runners wearing leather is so cool they've got to encourage players to get it. This post has been edited by Austere Emancipator: Sep 22 2004, 08:03 AM |
||
|
|
|
||
|
Sep 22 2004, 08:18 AM
Post
#17
|
|||
|
Moving Target Group: Members Posts: 313 Joined: 5-March 04 From: UK Member No.: 6,125 |
Man-portable, which still leaves the question of Detritus the troll... (Speaking of Detritus, the psychological effect of a troll with what is essentially a ballista should be taken into account...) |
||
|
|
|
||
|
Sep 22 2004, 10:09 AM
Post
#18
|
|
|
Target Group: Members Posts: 40 Joined: 16-September 04 From: Paris Member No.: 6,669 |
Hmmmm... Detritus.... My Hero ! :D
|
|
|
|
|
Sep 22 2004, 10:20 AM
Post
#19
|
|||
|
Moving Target Group: Members Posts: 486 Joined: 4-August 04 From: Fomorian Wastes Member No.: 6,538 |
125 grain for the arrowhead, yes, but there is also the shaft to take into consideration. Minimum Shaft Weights Modern performance shafts have three basic designs - aluminium tube, carbon fibre tube, and hollow carbon fibre tube containing an aluminium tube. As the poundage of the bow increases the weight and stiffness has of the arrows has to increase. If it doesn't the arrow begins a curving, whipping flight to the side. Over 6 STR archers will be using relatively huge shafts. Taking the recurve values as they have a closer correlation to STR required to pull the bow. At 6' tall the arrow length on average would be 33" long, and a pull of around 90lbs can be managed with a 4/5 STR. A powerful skilled archer (STR 6, Bow 5) can manage 120-140lbs pull, putting the total weight of shaft and arrow at a conservative 1,800 grains for a 6' human. This is just the start as compound systems decrease the poundage at full draw. The peak draw listed in the table for compound systems is the poundage when the string is about half drawn, full extension poundage can have 35%-60% drop-off. Compound bows deliver an accelerating "push" to the arrow resulting in a lower trajectory and faster flight speed. Current compound bows are not generally built to a maximum pullable poundage as the arrows would punch through 5" thick wicker targets at a distance of at least 80 yrds. My old, cheap 68lb compound will punch the arrows through up to the fletchings at 40-50 yrds. Utilizing the front of a hollow shaft to contain secondary effect materials reduces the strength of the arguement on comparing arrowhead mass to bullet mass. A hardened needle tip could be used for initial penetration, whilst the explosive packed forward end could be used for the secondary effect containment and delivery system. In fact, archers with >6STR would need to adding filler material to the shafts just to stop the shaft looking like an extra-long havana cigar. For a STR 10 troll using a bow the total arrow weight would be measured in 1,000s of grains, not 100s as used for bullets. NB. Any arrow shaft to be used against armour targets would need to be hardened. The last time I missed the backnet and hit a brickwall next to the target I ended up with a brand-new aluminium shaft 4 inches long and 1 1/2 feet wide. CF shaft are more likely to "bounce" of a hard target, but can still shatter, sending fine carbon fibres across the immediate area. For those of you who like to know the name of a 125 grain field point. Carbon Terminator Hunter Select |
||
|
|
|
||
|
Sep 22 2004, 10:54 AM
Post
#20
|
|||
|
Great Dragon Group: Members Posts: 5,889 Joined: 3-August 03 From: A CPI rank 1 country Member No.: 5,222 |
Apathy's question was specifically about shaped charges, which need to be very wide for a significant length. The shaft is useless for that, all the mass would have to be in the actual arrowhead, and even then in the rear-half. For a simple explosive arrow design you could use the whole shaft, like I already mentioned in the opening post of this thread. The smallest effective HEAT/HEDP warheads in conventional weapons are in small-caliber cannons and grenade launchers. Those are generally speaking in the 2000-4000+ grain range. The explosive charge, detonator and necessary casing on an M789 30mm cannon HEDP round weigh about 1500 grains. Of course you are never going to get anywhere near the performance of a cannon or GL from an arrow anyway. You might be better off with even a 300-400 grain shaped charge than just the kinetic energy -- below that I have serious doubts if a shaped charge could possibly be effective. That's still 350-450 grains per arrowhead, though. And, like I said, the "How this might work in the fictional world of SR" discussion is rather pointless because the best way to model this in SR is the (EX-)Explosive Arrowhead. This post has been edited by Austere Emancipator: Sep 22 2004, 11:01 AM |
||
|
|
|
||
|
Sep 22 2004, 11:39 AM
Post
#21
|
|
|
Moving Target Group: Members Posts: 241 Joined: 20-September 04 Member No.: 6,682 |
Okay, here's what I've got... I checked the str min tables and such, then checked the weight-bearing calculations.... basically at 10str, with a ranger-x bow, you're going to have a minimum pull of around 200kg (10strx20KG=max lifted).... which is brutally insane. Add to this the fact that it's a compound recurved bow in all likelyhood, and we're dealing with some truly absurd velocities. This means a bloody large arrow, basically. At this speed an obsidian arrow head honed to a surgical edge would fracture as it penetrated, but would still achieve penetration of most personal armor. This is due to the peculiar properties of using a glass head instead of a ductile metallic one, namely that the head does not bend, the edge does not turn, and the material does not compress. Instead it will sheet and fracture as it continues to penetrate. The explosive would be mounted in the junction of head and shaft, and is only designed to flechette the arrowhead, not inflict damage in and of itself. The primary question is shape of the arrow head and composition of the shaft.
A knife stab and the impact of an arrow are not comparable, to be honest. You're dealing in different orders of magnitude. As to using a cannon instead, a cannon isn't start legal, thankfully. |
|
|
|
|
Sep 22 2004, 12:38 PM
Post
#22
|
|
|
Moving Target Group: Members Posts: 486 Joined: 4-August 04 From: Fomorian Wastes Member No.: 6,538 |
I was indicating that a high STR human archer wouldn't have any problem using a 300-400 grain head, trolls/big orcs/cybers with an exceptional strength wouldn't have much issue with using 2,000 grain explosive systems either. In fact at least that has to be added to the complete arrow weight to maintain normal ballistics.
You need to stop comparing bullets to arrowheads or are you only ever talking about the very tip of a bullet. The whole arrow is the same as the bullet(sure, only part of it may enter the target, but all of it is fired at the target). Therefore an explosive arrow designed for armoured targets has much more available mass/volume for the shaped charge. The reason for the limitation of around 100-125 grains for a standard arrowhead today is a practical use issue. If you change the head on an arrow it is desired that it has stable/similar flight charactics independant of which arrowhead used Here's my munchkin bow. Dual-bolt cross-bow with power assisted "winchester" draw mechanism. Smartlink II attachment with distance/target size computation Frangile explosive fibre/mono-filament shafts Delayed explosive frangible heads Trailing mono-filament line linking each bolt together. The adjusted smartlink system computes distance to target of x size. The angle of the flight path of each bolt is adjusted to so one or both bolts "miss" to the side. The causes the tethered bolt to pull the mono-filmament into the target. After a short delay the shaft and head explode for secondary/tertiary fragmentation damage. All for the price of hiring 5 guys with big guns to do the job for you. :D |
|
|
|
|
Sep 22 2004, 12:52 PM
Post
#23
|
|||
|
Moving Target Group: Members Posts: 486 Joined: 4-August 04 From: Fomorian Wastes Member No.: 6,538 |
The poundage does not directly correspond to speed on a bow. Higher poundage must have heavier/stiffer arrows and result in a longer accurate range with more stopping power, not blinding fast arrows. As we are definately out-of-canon for obsidian:- 1. The shafts are going to be almost completely unavailable for that poundage bow and should have an insane availablity. 2. The bow would have to be a complete custom-build, normal limb materials cannot contain that much energy. 3. And what facility do you have access to make shafts out of SOTA materials so it doesn't fragment when the head contacts armour and still maintains a narrow diameter? Unless your guy is a troll I can't see have you can maintain arrow weight/stiffness characteristics on a 32"-34" arrow at STR10. |
||
|
|
|
||
|
Sep 22 2004, 01:35 PM
Post
#24
|
|||||||||
|
Great Dragon Group: Members Posts: 5,889 Joined: 3-August 03 From: A CPI rank 1 country Member No.: 5,222 |
The smallest (in diameter) conventional shaped charge in use by the US Armed Forces that I am aware of is the above M789, which is 30mm with the casing. An arrow shaft is simply not thick enough to allow for a shaped charge placed inside. Additionally, making a shaped charge much longer at a set diameter will not increase the penetrating power of the charge significantly. You could make the whole shaft out of an explosive, but what would really matter for the penetration, and damage done to the target when we've got impact detonation, would be the explosive inside the arrowhead. Packing explosives all along the shaft might be worthwhile because of area damage with heavy arrows, though -- but when considering the feasibility of shaped charges, it's all about the arrowhead. The only explosive bullet design that I am aware of that is in use with a military IRL is the .50 BMG MK 211 MOD 0 API "Multipurpose" round, with a projectile weight of 671gr. A design like that only works because you can get it to hit the target at several mach already, and the penetrator itself is very small and dense. No use in an arrow.
I already admitted a 300 grain arrowhead even without using particularly powerful bows in my first reply to Apathy, which is why I used the 350-450 grain figure for a shaped charge for an arrow.
Is the main purpose here only to kill the one target and not do damage to people around? If so, monofilament "fragmentation" is kinda cool. You'd want it inside the enemy, though, because such extremely light and brittle fragments would be rather easily stopped by armor. They'd certainly cut nasty wounds once they get to flesh, though.
Not really. NIJ Stab Protection Level III type armor must have less than 20mm penetration from an icepick-like steel spike dropped on it with 48.5 ft-lbs. This page lists the kinetic energy of a 60lbs bow with 500gr arrows at 53.6 ft-lbs. We're definitely in the same energy range here. The real difference would be that an arrow is a light, fast-moving object, while the ice pick is a heavy, slow-moving object. In this respect, an arrow is much closer to a bullet than a stab. Which is why a vest rated to protect both against handgun bullets and stab wounds would be optimal against an arrow IRL. This post has been edited by Austere Emancipator: Sep 22 2004, 01:42 PM |
||||||||
|
|
|
||||||||
 Sep 22 2004, 02:49 PM
Post
#25
|
|
|
Moving Target Group: Members Posts: 241 Joined: 20-September 04 Member No.: 6,682 |
okay, the issue however is the profile of impact. most bullets have a blunt impact profile, as opposed to the fine edged penetrating edge of the arrow. An ice pick is pretty sharp, sure, but not REALLY sharp, which shifts the distribution of force applied. It's a closer comparision than to a bullet, but it's still pretty far off.
"Is the main purpose here only to kill the one target and not do damage to people around? If so, monofilament "fragmentation" is kinda cool. You'd want it inside the enemy, though, because such extremely light and brittle fragments would be rather easily stopped by armor. They'd certainly cut nasty wounds once they get to flesh, though." That's basically what the obsidian head does when the charge blows. "As we are definately out-of-canon for obsidian:- 1. The shafts are going to be almost completely unavailable for that poundage bow and should have an insane availablity. 2. The bow would have to be a complete custom-build, normal limb materials cannot contain that much energy. 3. And what facility do you have access to make shafts out of SOTA materials so it doesn't fragment when the head contacts armour and still maintains a narrow diameter? Unless your guy is a troll I can't see have you can maintain arrow weight/stiffness characteristics on a 32"-34" arrow at STR10." I am using a ranger-x bow, with a legal str min code, so it is actually within the canon. Some way or another there are shafts that can take the stress. How would you calculate the pull for a str 10 min bow? As I understand it, str min is literally the minimum strength to pull the bow, so it would match up. Draw length is an issue though... hmm.. still it looks pretty feasible to design an arrow with a d code. For the bow limbs, I would use extremely long chain memory polymers braided onto a carbon weave latice. Or something similarly silly and super-techy. Clearly, given the way ranger-x bows and their arrows scale, shadowrun arrows will go through armor with high str min bows. You'd prolly use the shaft of a ranger x arrow and work from there. "kinetic energy of a 60lbs bow" 60lbs=27.3kg... so that bow's pull is for whatever reason, probably comparatively tiny, if you wanna go with pure canon measurements. Let's set out the assumptions... the arrow shaft will likely be at least 1000 grain. the arrow head will probably be 100-300. the arrow length is 30. the draw of the bow is strmin-10. str 10ers have a max lift and hold of around 200kg according to the rules if I remember correctly, so that's our ceiling for the pull. What SHOULD we use? what if we put a sabot style discarding penetrator on the obsidian head so that we get both a fine point impact and broad head cutting edge..? I think it IS workable. |
|
|
|
|
|
Lo-Fi Version | Time is now: 25th April 2024 - 10:36 AM |
Topps, Inc has sole ownership of the names, logo, artwork, marks, photographs, sounds, audio, video and/or any proprietary material used in connection with the game Shadowrun. Topps, Inc has granted permission to the Dumpshock Forums to use such names, logos, artwork, marks and/or any proprietary materials for promotional and informational purposes on its website but does not endorse, and is not affiliated with the Dumpshock Forums in any official capacity whatsoever.