Rope Arrow Concept

[sparhawk]

I would like them re-usable because you can get into all kinds of interesting places with only two rope arrows by being careful about where you fire them so you can always retreive the last one.

 

Exactly my point I almost never lost my rope arrows because Ialways retrieved them.

 

BTW oDDity's concept is cool - but that corkscrew could be a waste of polys - AFAIK the engine will still render them once its embedded them in the wall, its just that the Zbuffering will overlap them with the wall.

 

Do they need to be polys? I thought the arrow could be just a stick, and the textures makes the rest?

[oDDity]

I want you to describe exactly how the magic rope arrow design works.

Are you saying that it's just a wooden shaft and a broadhead, and when it hits a surface, a rope magically materialises from nowhere, the wooden shaft it strong enough to hold a man's weight, and when you manage to prise the head out of the wood, the huge thick rope magically dematerialises again? How many ropes is this arrow capable of spawning exactly? I suppose it's everlasting magic is it?

*rolls on floor laughing*

And you have the nerve to say you have problems with my concept??

*goes back down for another round on the floor*

 

The corkscrew arrow won't use many polys, alpha maps can be employed.

IT CANNOT be reusable, since you can no more put the rope back inside the arrow than you can put an egg back together once you've cracked it. THough I suppose I'll have to conceed that one, since everyone wants it to be reusable, even if it's silly.

The arrow is NOT too heavy. It is hollow remember, not solid metal, and and it doens't have a big fat broadhead tip either. You don't need to shoot rope arrows long distances anyway, so having a reduced range is fine.

As for what the rope is made of - take your pick. There are materials availble which could make a thin cord that was light and perfectly strong enough to hold your weight, there's no problem there, and you are wearing leather gloves on your hands for grip.

[Subjective Effect]

Well of course I agree with a spinning arrow with a corkscrewing motion - but not that corkscrew head.

 

My idea was this type of corkscrew that is bladed -

 

http://images.google.co.uk/images?q=tbn:SC...screw%25202.jpg

 

But that tapers to a point.

 

With a corkscrew flight the arrow would both spin and have penetrating power by dint of the weigh and sharp point. And you can have a rope un-winding mechanism that is dependant on the spining momentum - both the head and the wound up rope are spinning in mid-air. On impact the head stops but the rope un-winding mechanism does not and unfurls the rope. And since the rope is attached close to the head the shaft can be wooden and the wood bore assembly would hold the thief's weight.

 

 

The rope would be pretty bulky. And of course you can wind the rope back up.

[oDDity]

I like the bladed corkscrew better, but there's no way that spindle design would work for the rope. That much rope would never fit around such a small spindle without ending up in a massive ball the size of your fist.

Much better to use the whole length of the hollow shaft to hold the rope.

I've been looking at the cord which operates the venetian blinds in my house. It's very thin, but also very stong and could easily hold my weight - and I'm over 200 pounds. Yes, it would be tough to climb wiht bare hands, but with a pair of thick leather gloves (whihc out thief has) it woud be no problem. This cord is also very light, and it could easily be wound up inside a hollow tube the size of an arrow shaft.

Also, having wound up a section of it, I'd estimate you'd be able to get 10 metres at least inside an arrow shaft which was half a meter in length.

[Springheel]

I want you to describe exactly how the magic rope arrow design works.

 

The rope is imbued with the same magic that slowfall potions have. Anyone on the rope becomes essentially weightless, explaining why it holds the thief's weight without having to burrow a foot into the wooden surface.

 

The arrow has a short rope coiled inside, which magically stretches once it is deployed.

 

The only magic needed is already established in the game. Magic that makes things lighter and magic that makes plant-material grow.

 

And you have the nerve to say you have problems with my concept??

*goes back down for another round on the floor*

 

Yes, yes, we all know by now you don't like magic, but that's the only way a rope arrow could conceivably work. I find it equally hilarious that you seriously think your concept could work with real world physics.

[oDDity]

That magic arrow doesn't make any sense. does it?

If such magic existed that makes you weightless, he wouldn't even need a rope arrow, he could just touch the rope and float around in the air, or why doens't he use a magic carpet and avoid all the guards?

That's where these ridiculous tales of magic take you.

 

 

The new rope arrow design would work, and the bladed corkscrew that SE posted is even more realistic. It could be made in real life, if anyone was stupid enough to put the time and money into creating it.

[sparhawk]

Go and build it. But I wouldn't climb over a chasm the first time with it, because you could be in for a surprise.

[oDDity]

Yeah, I'd be safer just flying over it on my magic carpet :/

[sparhawk]

We can try to come up with a realistic explanation for flying carpets as well. You did such a good job with the rope arrow, I'm sure you can do the same for the carpet.

[New Horizon]

Yeah, I'd be safer just flying over it on my magic carpet :/

<{POST_SNAPBACK}>

 

 

That I would love to see.

[oDDity]

No chance, the magic carpet makes you invisible as well, for extra protection against those pesky guards.

Anyway...this bladed screw tip is a better design I think.

[Subjective Effect]

It looks a little fragile to me. Not as fragile as the original but still fragile.

 

The image I linked to but can't display looks pretty sturdy as it has a central core, unlike both of your concepts oDDity.

 

And if a narrow cord like the cord on blinds can be used then you can have it on the spindle I suggested. It would indeed be a large bulge, but I think it will look good and look feasable. NB. My little sketch is not meant to be to scale, it was the concept I wanted to get across.

[Springheel]

That's a better head, yes. It still wouldn't actually penetrate wood without some kind of pressure behind it (the way a person has to actually HOLD and PUSH on an electric drill to get it to dig into wood), but that's moot. It just boggles my mind that anyone could actually think something like that would work without magical aid. It's like arguing the T2 robots could actually work using steam technology.

[sparhawk]

Why should they NOT work with steam technology? Actually I knew a collegue who did something like this as a master thesis. Not with steam but with water. He built logical gates using water instead of electricity and with this he could build something like a computer, because it doesn't matter how a logical gate is switched and a computer is doing just the same. Electricity is only better because it allows for much smaller devices and is much faster, but there is nothing inherent in logical devices that requires electricty in the first place.

 

BTW: I like the second concept also. It looks rather good and distinctive. A slong as nobody tries to tell me that this thing would work in reality. I have no problem accepting such an arrow just as I accept a crystal arrow but I would love to have distinctive arrows like this instead of just crystals.

[New Horizon]

I wonder if the feathers around the tail should be slightly spiraled around instead of straight. This might cause the arrow to spin when it's fired.

[Subjective Effect]

Ahem.

how about a corkscrew/spiral drill head with a spiral flight so it looks like it's supposed to "drill" into the wood?

<{POST_SNAPBACK}>

[oDDity]

This is one with the spindle. It's look more visually appealing since you can see the cord, but there's is no way in hell you could get 10-15 metres of ropes spooled around that without is being enormous.

I suppose it could be strechy rope. Magic isn't required for a stretchy elastic rope, just a rubber tree.

I don't know much aboiut ballistics, so I'm not sure if spiralled flights would make it spin or not. I'd prefer some sort of mechanism inside it, becasue it would require quite a lot of energy to bore into wood.

[Springheel]

Why should they NOT work with steam technology?

 

Because they are more sophisticated than modern robots, for starters, none of whom can walk on two legs, run when necessary, pathfind around a home, "see" intruders and be able to distinguish them from people who live there, pick and choose voice sets appropriate to the situation, etc, etc---all fitting in a chasis the size of an oven.

 

Even something basic, like how a robot sees--and recognize what it sees--using steam technology, is absurd.

[Subjective Effect]

Damn you work fast oDDity!

 

That spindle is sweet. If you make it 1 1/2 times the length and put double the rope on it, then shorten the head by 1/3 and make it twice as fat and with a solid core like this (see how the solid core would make it more solid and give it better penetrance?):

 

 

And you will have exactly what I was thinking about, just with oDDity stylee.

 

Spiral flights will cause an arrow to spin. In fact spiral flights make the arrow fly in a straighter line and were commonly used just for that.

 

http://www.huntersfriend.com/arrowhelp/arrow-selection-4.htm

"If your fletching is arranged in a helical (spiral) pattern - like a boat propeller - your arrow will rotate in flight. Much like a football that's thrown with a perfect spiral, an arrow will fly straighter and be more stable if it rotates in-flight."

 

http://www.rockymtbroadheads.com/article-j...loan-arrow.html

"Most archers like their arrows fletched with a slight spiral. This causes the arrow to rotate during flight and helps stabilize the arrow."

[oDDity]

~The spindle can't really be made any longer. Remember that the arrow can only be drawn back as far as the bare shaft allows, you couldn't draw it back past all the spindles and rope. A huge bulky rope ball would also interfere with the flight of the arrow I'd imagine. I think it would be better to keep the spindle and rope small, and say it's elastic type rope which will stretch.

[Ishtvan]

I respect the engineering effort that is going into trying to make a realistic rope arrow, but you'll still have problems with putting enough load-bearing rope on the arrow to span any sizeable distance and not have the arrow fly like shit. This is using modern polymer processing to make the rope, let alone what they had back then. I'm just going to quote my post from over 6 months ago:

 

Old Post:

 

The problem I have with realistic rope arrow is the added mass of all that rope to the arrow. A heavier arrow, when shot from the same bow, will not fly nearly as far as your basic broadhead. If you don't believe me, here's the physics explanation below:

 

[Physics Explanation - Skip this if you already understand why this is]

The bow can only impart so much kinetic energy to the arrow. In the most simple model, think of the bow a system of several springs. The most kinetic energy it can impart to the arrow is equal to the potential energy of the springs when the bow is fully drawn (in reality it will impart a little less, due to friction losses, etc). Okay, so we've got some number in mind for the most kinetic energy the bow can impart to the arrow.

 

Now as some of you may remember from high school physics, the kinetic energy of the arrow is 1/2*mass*veloctiy^2. Set this equal to the max potential energy of the bow when fully drawn. max potential (bow) = 1/2*mass*velocity^2 (arrow).

 

Solve for v:

 

initial velocity = sqrt (2 * max potential / mass ). [1]

 

Since the max potential is always the same for a given bow, you can see that increasing the mass of the arrow decreases the arrow's initial velocity when fired from the bow.

[End explanation]

 

Now, think about how long a rope you need to climb up 5 stories (~50 ft / 15 m). How much do you think that rope weighs per unit length?

 

With MODERN polymer materials, I got some numbers from this climbing rope company site: http://www.yatesgear.com/climbing/wallropes/ . It weighs 55-77 g / meter. So for a 5 story rope,

total modern rope weight = 15 m * {55-77 g/m} = 0.825 - 1.16 kg

 

Now for MODERN broadheads, "Minimum arrow weight was determined to be 25 grams." [ref: http://www.bagjakt.org/study_eng.htm ] So now we have enough information to calculate the fractional decrease in speed when going from a broadhead to "broadhead + rope"

 

Plug everything into [eq 1] :

 

velocity_ropeArrow / velocity_broadhead = sqrt( 0.025 [kg] / (0.025 + rope_mass [kg] )

 

velocity_ropeArrow / velocity_broad = 0.17 (based on lightest modern rope)

 

velocity_ropeArrow / velocity_broad = 0.14 (based on heaviest modern rope)

 

Conclusion

With MODERN materials, adding 5 stories of rope to an arrow will decrease the initial arrow velocity (and therefore how far it can travel) to 14%-17% of a broadhead's initial velocity! This means shooting a rope arrow from a shortbow would be like shooting one of those NERF bow and arrows, compared to the broadhead. There's no chance in hell that you'd be able to shoot that 5 stories up (maybe with the Bow Upgrade )

 

This analysis didn't even consider the heavier tip you would need to anchor on to things. Also, all the numbers used were for MODERN materials. Polymer ropes, aluminum/graphite epoxy composite arrows, etc. Rope arrows would fly even worse using the technology they had in medieval or even Victorian times. I guess you could make up something about using "spidersilk" rope or some crap like that... but at that point, might as well use magic.

[sparhawk]

Your analysis also doesn't consider that, not only to shoot it hat 5 stories (though I would say three is more then enough) it requires additional energy, it also needs additional energy to embed the heavier tip inot the wood in order to penetrate far enough to carry your weigth. So you need more energy to shoot it the same distance, you need a heavier tip to hold your weight (acutally more then just your weight because of the added tenstion of the movment while climbing) and for this heavier tip you again need additional energy, and to embed it enough you would yet again need additional energy.

[oDDity]

The great thing is, we don't have to build the arrow in real life. It's for game purposes only, and I can guarantee that no one will go to the length Ishtvan did to prove it wouldn't work.

Anyway, the rope is pretty short and elastic now, so all your calulations are off.

It's still better than attatching a rope to the end of a broadhead and saying it works by magic.

[sparhawk]

It's for game purposes only, ...

 

It's still better than attatching a rope to the end of a broadhead and saying it works by magic.

 

LOL

 

Why?

[Ishtvan]

All that being said, I can't resist making another suggestion for the realistic rope arrow. I don't have time to make pictures, so you'll have to deal with textual explanations, sorry.

 

1. There is no rope wound on or inside the arrow. Instead, the arrow has a ring on it. One end of an extremely thin and light fiber (piano wire?) is anchored in place on the ring, by a releasable weight (we'll get to that later). The rest of the fiber is attached to a spool that's designed to release with extremely low friction (this could be attached to the bow temporarily or something when you select the rope arrow).

 

2. When the bow is fired, the fiber trails behind the arrow, feeding out from the bow with very low friction.

 

3. On impact: The corkscrew head somehow burrows into the wood. This could be accomplished with an explosive charge, or a pressurized gas (steam) release that's vented in a way to rotate the arrow tip and drive it in. If you're looking down the length of the arrow head, one explosion vent would be on top, pointing back and to the left, the other would be on the bottom, pointing back and to the right. When the explosion went off, it would both push the tip in (since the vents are pointed somewhat backwards) and screw it in, since the vents on top and bottom are pointed left/right to rotate it.

 

4. Also on impact, the weight that's holding one end of the thin fiber drops down, drawing more of the fiber thru the ring.

 

5. Now you have the arrow, burrowed into the wall, and you have a thin fiber that's going thru a ring on the arrow, and access to both ends of the fiber. It's time to replace that fiber with something that will hold your weight.

 

6. Cut the fiber off from your spool and tie the fiber end to one end of a thicker, load bearing rope.

 

7. Grab the other end of the fiber (the one that was attached to the weight that dropped down from the arrow). Pull on that end so that you lift the thicker rope up and thru the ring, replacing the thin fiber. You now have two ends of thick rope going up to the ring on the arrowhead, and can climb it. (Alternatively, you could attach some kind of anchor to the far end of the rope, so that you could pull it all the way thru until that anchor hit the ring, then you would only have one rope trailing down instead of two).

 

I know that seems a bit convoluted, but the main advantage is that it lets you fire a light arrow with thin thread, and then pull the heavy rope up afterwards, when the arrow has already flown and burrowed in to the wall.