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Automatic Crossbow
Published: 2013-07-13 16:24:47 +0000 UTC; Views: 90965; Favourites: 1819; Downloads: 1032
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Description
Hello. This thing might actually work out. Mechanic in the back pulls the bowstring with the slide, the slide pulls an arrow out of the magazine, shoot...simple and fast reload system.Blender/cycles
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Comments: 276
i focus on what i did right but thanks...
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If bolts are solid metal, then arm and string are to flimsy for them to have proper strength for the crossbow to work.
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looks sweet but would be inaccurate as shit with no fletching on those bolts
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thanks.the slide keeps it in line
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The point of fletching is to keep it stable in flight, even if its fired at an extremely high velocity it will be inaccurate without it.Β Its the same reason guns have rifling.Β The spin on the bullet makes it more accurate.
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This looks great. How about a really powerful crossbow with a hydraulic drive?
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thank you, i didn't saw that one coming
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I love the design for the bolts. Β Very steampunk-clockwork-ish, and my kind of ammo!
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You're welcome.
By the way, was that a 3-D drawing or something? Β I noticed you said it only might work if it was actually built.
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First automatic crossbow I have ever seen. I love it.
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Van Hellsing and ol' Gretel use one.
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That is an absolut normal desire
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"Mechanic in the back pulls the bowstring with the slide, the slide pulls an arrow out of the magazine, shoot...simple and fast reload system.
Blender/cycles"
unfortunately it wont cycle, after the arrow is shot? SMGs and semi-auto pistols work on the principal of blow-back action(recoil) to push, eject and then have a recoil spring push it forward to chamber a new round. Assault rifles and battle rifles use mostly gas tapped from the barrel instead to cycle the mechanism, either the the gas pushes a piston or it uses the gas directly to the bolt carrier.
en.wikipedia.org/wiki/Gas-operβ¦
Great design, but not very easy to create.
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Cycles is the render engine in the 3d software Blender wich i used to create that objekt. With mechanic i mean a motor wich pulles the slide back...still simple.
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Well, simple in theory. Making an physical effective return actuator capable of repeatedly and rapildly drawing back a 150/200-pound drawstring, without affecting it's physical properties, that's also small enough to be inside the weapon body, along with it's power source... OH and fails to jam after many, many shots...
That's a $2,000,000 research project in of itself. minimum.
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That's why I was thinking about a hydraulic draw-back system, e.g. with an axial piston pump. It could potentially be more powerful and quiet.
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that looks... pretty complicated. Simpler the better usually... 4 actuators with associated valves, miniaturised. Hum. Quieter though, yeah. Remember it has to be able to fire 3 mags without reloading working fluid, minimum.Β So it'll need low slippage, and a high efficiency, which is difficult with those sort of systems.
Using human power is still quieter, at a low bet. Loosening and tightening the string would reduce difficulty but then you need syncronisation of tightening systems... at that scale that could prove difficult. Who's your reference and source of expertise on this? My engineering experience is not in this field so I can't verify any of this.
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Soulfreeze, I have some experience with auger boring machines and most of this stuff is hydraulically powered. Some of this equipment is able achieve over 400 tons of force to push steel pipes into the ground. Similarly AVN class machines are able to push hundreds of meters of large diameter concrete pipe deep underground with hydraulic actuators. TBM machines also use this system to press the cutting shield and use hydraulic gear to rotate the disk. Generally, hydraulic actuators are probably the most compact and powerful device that is suitable for "dirty" conditions.
The reason to use hydraulics in a crossbow is their small size and very high leverage, so the user would theoretically be able to pull the string manually, simply by pushing e.g. the trigger repeatedly (although that would be tedious if you want hundreds of kilograms!). You could also use the manometer to calculate the energy of the projectile. You are right, a small-scale hydraulic device would probably require high precision manufacturing.
I guess I sould stop here and abstain from discussing the trigger systems, which are probably the most illegal thing about this
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Well okay, the expertise has stepped in and informed us that small-scale actuators can provide us with the necessary force required, albeit with high-precision engineering possibly required. Thank you Krazzt.
So why then is this auto crossbow better than a gas-fed flechette launcher, or an M40 GL firing pointy flechettes or heavy darts? Chemical propulsion is almost more reliable, and has a single consumable, right?
Surely there's a chemical expert that can compare safety factors of repeated-stress bow strings against a gas projectile?
Technically the bolt could be fired by a gas launchtube?
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You really should have seen the glow of my eyes that suddenly illuminated the room and painted the walls and windows bloody red as my gaze stopped at "gas-fed flechette launcher"
Thanks for your insights. Yes, you have a point. Still, the aim of designing a hydraulic crossbow is to create something unorthodox: a portable and qiuiet launcher capable of delivering kinetic energy comparable to an APFSDS.
By the way, the military's answer to your last question is sabot. The design of APFSDS is all about firing bolts from launchtubes and maximizing muzzle velocity.
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Heh. Well engineers think of new ways to do things. It wouldn't be accurate without some serious design and materials.
Maybe. But tbh human power is still quieter, and like the role of the Colt 1911, if you've used all eight, you need a bigger gun - a rapid crossbow is nice, but not useful in the stealth situation it's designed for. Not optimised, per se... wouldn't you agree?
Yeah a SABOT type delivery would make a gas-fired bolt pretty accurate.
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I saw a clip on you tube with an automatic crossbow.... didn't looked like 2million at all more like homemade.
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link me. let's see. Home-made and combat ready are really different... how rapid?
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www.youtube.com/watch?v=BSjCY2β¦
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Althought I am wondering the poundage of his bow. mind you, military grades would have no problem scaling it up. Just Curious.
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Huh. I stand corrected. Consider my arguement invalid, and me very wrong. you win sir. congratulations.
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Thank you! It just took a badass hippie to convince you but oh well...
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If it can be home modded then usually it's not hard for the military to do smoothly. however an actuator for a 150 pound or 200 pound crossbow might take a lot, so it depends if the batteries can go small enough. His crossbow wasn't a massive poundage from the look but it's hard to tell without stats.
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I really like the style, especially to front part. Unfortunately the rear part doesn't seem to fit in regards to the level of detail. The butt and especially the hand grip are at least 2 levels below the level of detail of the front section. The grip looks extremely boxy from the rear and doesn't reflect the nice roundness of the front...and I don't like the that beige/light pink color.
But that's just my 5c and can ignore if you think it's BS
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I hope I didn't offend you with my comment?!? That wasn't intended.
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awesome design as always and well done one the materials! 
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Very awesome, but I wonder if a custom drum magazine would work.
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sure. the drum magazine was on my first sketch, later changed into some kind of ak magazine ended up with the simple versionyou see
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This is beyond the magnificent!!outstandingly beautiful design and render workmanship! Congrats,But I wanted to ask; which program you use for modeling and rendering!?
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thanks a lot man. Now you found out what i work with, ever tried blender?
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Your welcome
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