Simulating Recoil

[Frostbyte]

Hey guys, I've been thinking about what it would take to create a rifle (probably BR or Sniper) that would have a working trigger and would simulate recoil when the trigger is pulled. As far as i know this has never been done outside of movie theatre arcade games. I figured it'd be a very cool thing to show off and make it seem more lifelike.

I haven't taken the time out to do an actual drafting of the models, but I just doodled one out real quick, hopefully you can see it :s sorry hahaha

(The design is intended to only show the trigger and the bolt, but have a removable side panel for maintenance, and it will all be mounted in a shallow box covered by foam or pep.)

The orange designates PVC piping. Inside the lower pipe is a weight (basically a piston) which slides back and forth inside. on the butt end of the weight, it is connected to a spring (i figure a trampoline spring; 40lbs spring for ~$6). Around that spring, also inside the PVC is a smaller pipe which is about as long or slightly longer than the spring; this is where the piston will impact, and the opposite end will transfer the force directly to the butt of the rifle. On the muzzle side of the piston, there will be connected a line (maybe para-cord) which will follow the U-shape formed by the 2 PVC elbows. The other end of the cord is connected to the bolt; this way when the bolt is pulled back, the piston will be pulled forward, putting tension on the spring. then the trigger (and i forgot to draw this part, my bad :$) which has a spring under the forward part, will push up into place to hold the piston steady. Finally, squeezing the trigger releases the piston, which then causes chain reaction which ends in simulated recoil.

now obviously there are some specifics, such as the box having a hole for the trigger, mounting the trigger so it can properly rotate, the hole in the lower pipe for the upper trigger, the make of the piston (whether metal, sand-filled for dead-blow effect, etc), a backing behind the upper trigger so the spring and piston don't snap the trigger, what to make the trigger with/how to make it, the list goes on, but I'm sure we can figure it all out.

Btw, this would work with a shotgun too, just flip it and the pump is the bolt ;D

with the materials shown for the system alone, coupled with thriftiness and scavenging, i figure i could make this for about $50 or less!!

and if we really wanted to get crazy, we could add an LED flash to the muzzle with a battery and some kind of sensor or circuit completing something or other, but lets start with this

Anyway, I'm EXTREMELY eager to here your ideas, comments and questions, especially if you have an idea on another way that could be easier!

(*ps my first thread/content post so dont kill me c: )

 

[nikolojedison]

A rumbly rifle would be really cool. An easier way to do it might be to do something like an Xbox controller's rumble, with the spinny weights and such. As far as glowy LEDs, why stop at the muzzle flash? This would work best on Forerunner weapons or the like, but maybe the LEDs all over the gun 'pulse' when you fire? Just a thought.

 

[Frostbyte]

I think rumble packs would be really cool for automatic weapons! But as big as they are, I'm not sure a normal set would quite do the trick, you'd have to make it bigger or do more units or something? Somehow motorize a shakeweight haha

And yeah i was planning on doing lights and a scope, but didn't mention them because they aren't really interactive, they'd just switch on and off

 

[FoxtrotZero]

This could definitely be done, but it would also only work weapons where you have to manually cycle the bolt between shots. In Halo, I think the Shotgun is the only weapon with this quality (though you could implement this into the Sniper Rifle without anyone but me giving you a second look). The biggest difficulty to me seems like you've got a lot of small parts, and getting everything to work exactly as you want might be a bit more difficult than you think.

If you're so much as considering putting electronic components next to this, you might want to look into the prices for some sort of cheap board (arduino or raspberry pi? I don't keep track of these things) and some kind of linear actuator with a weight attached to the end. This would allow semi-automatic fire, light and sound control (with the requisite hardware), an ammo counter (if you're adventurous), and a reasonable rate of fire (depending on the reset time for your actuator). I don't know how much parts like this cost, like at all, but I don't think it could be outrageously expensive. It would also require more soldering and programming than physical tinkering.

 

[majorflint]

well I think your on to some thing with this I have a few airsoft pistols that run off green gas it gives them a nice recoil which adds to the feel ,
but like has bin said by nikolojedison some thing like a rumble pack in an Xbox controller should not be to hard to work out ?

 

[Frostbyte]

I was mostly going for a simplistic style, as i have v little experience programming stuff and would be on YouTube for weeks haha but yeah i think I'll have to look into it as an automated system would be pretty epic!

Btw i was considering using nerf gun parts where possible

 

[majorflint]

ok you bringing up nerf makes me think there some very cheep toy guns out there that not only make sound but do the rumble think as for programming I here you on that not my area im more ducked tape and hammer

 

[Frostbyte]

I'm sure i could figure it out, but all I'm really interested in as of right this second is how to pull the trigger and get realistic recoil... im trying to think how heavy the weight needs to be to put out enough force

 

[Sirdanmartin]

Wow this is a really interesting idea. I feel that in order to do this you would want to do it to a weapon that already has a fair amount of weight to it as doing it to a flimsy foam weapon wouldn't be much fun. In which case it your going to want to use a fairly heavy weight with a good spring on it.

I think this could be done fairly well if you stick to it. I'm just going to stick to the classic pow noises with my mouth while i shake the gun up and down pretending to fight the recoil .

 

[Frostbyte]

Just had another idea, if i put a connection between the barrel and the part below it, i could extend the length of the pvc and put more tension into the spring, as well as having room for a longer/heavier weight,without being too difficult to disguise

 

[OMANOMNOM]

If you want to have a moderate amount of recoil then you're going to want it made in metal, not PVC or any other plastic as it will tear its self apart. If i was you i would look at the internals of a Gas blow back airsoft rifle such as a WE SCAR, no matter how you look at it simulating recoil will mean ALOT of engineering.

 

[RobTC]

Yeah, all this talk of plastic whilst discussing 40lb (178N, apparently, since we're talking about force) springs and lumps of metal is somewhat disconcerting. You're not talking about pressure containment and release here, where SCH40 or SCH80 PVC can work just fine (as in a piston cannon), but impact forces. Repetitive impact forces are one of the toughest engineering challenges we've had- they'll break just about anything, eventually. Just look at objects designed to take repetitive impacts- pneumatic drills (jackhammers), tank turrets, etc. They're a mass of solid steel and spring dampers. Unless you have a damping assembly at the other end- ruining the "recoil effect"- it's going to break stuff quite quickly unless you're using threaded steel pipe, I think. Even then, you're going to have to watch carefully the force transfer between the piston shaft and the prop itself- specifically, how much surface area it's glued together over. Focusing all of that force over a one-inch circle or something is probably going to snap something pretty fast.

There's also the practical aspects. 40lb isn't all that much, but you'd probably be surprised how difficult it'll get after a few tries of just two curled fingers (SR) or a non-dominant hand at arm's length (M90).

If I was doing this, it would be CO2 operated, controlled by an Arduino nano operating solenoid valves (about two minutes' worth of coding), in all steel/brass/copper and connected to the superstructure at numerous points. I don't think that would be allowed in conventions (no pressure vessels, right?), but it'd be the safest and most consistent method. It would also go in the BR/AR/SMG with a little code alteration.

 

[Frostbyte]

If you want to have a moderate amount of recoil then you're going to want it made in metal, not PVC or any other plastic as it will tear its self apart. If i was you i would look at the internals of a Gas blow back airsoft rifle such as a WE SCAR, no matter how you look at it simulating recoil will mean ALOT of engineering.

Very good point on the topic of impact against the PVC, I hadn't thought of this. off the top of my head, i imagined making the smaller pipe several sizes smaller so that I can add a layer of bondo or liquid cement or something to the space between the pipes, and obviously the butt end would be capped off, and then add a ring of EVA to where the piston would impact. Then the outer PVC could be coated with Duct tape to hold it together if it does crack. But as far as any kind of compression tanks, pneumatic or nitrogen or what have you, I wanted it to be convention appropriate. Thanks for bringing that up tho

Yeah, all this talk of plastic whilst discussing 40lb (178N, apparently, since we're talking about force) springs and lumps of metal is somewhat disconcerting. You're not talking about pressure containment and release here, where SCH40 or SCH80 PVC can work just fine (as in a piston cannon), but impact forces. Repetitive impact forces are one of the toughest engineering challenges we've had- they'll break just about anything, eventually. Just look at objects designed to take repetitive impacts- pneumatic drills (jackhammers), tank turrets, etc. They're a mass of solid steel and spring dampers. Unless you have a damping assembly at the other end- ruining the "recoil effect"- it's going to break stuff quite quickly unless you're using threaded steel pipe, I think. Even then, you're going to have to watch carefully the force transfer between the piston shaft and the prop itself- specifically, how much surface area it's glued together over. Focusing all of that force over a one-inch circle or something is probably going to snap something pretty fast.

There's also the practical aspects. 40lb isn't all that much, but you'd probably be surprised how difficult it'll get after a few tries of just two curled fingers (SR) or a non-dominant hand at arm's length (M90).

If I was doing this, it would be CO2 operated, controlled by an Arduino nano operating solenoid valves (about two minutes' worth of coding), in all steel/brass/copper and connected to the superstructure at numerous points. I don't think that would be allowed in conventions (no pressure vessels, right?), but it'd be the safest and most consistent method. It would also go in the BR/AR/SMG with a little code alteration.

Thats some info right there hahaha I definitely appreciate it though-
i think a could probably find a narrow enough steel pipe that i could use for the inner pipe, but i need to be able to cut a notch out of the larger pipe for the upper trigger, and i dont have tools for that kind of arts and crafts class Also, for the butt/force absorbing section, i was planning on layering perpendicular layers of eva foam and a slightly stiffer material (maybe thin wood, idk yet), but then I'm concerned that the force on the center layers of the butt would cause the adhesive from the aesthetic paneling to break away.. maybe magnets? magnets are cool.

 

[RobTC]

Since effectively all you're building is a crossbow that fires backwards, all you need for the latch would be a hole. So if you can get hold of a metal file and an electric drill, you're good to go!

Layered high density foam is a good idea, though it's a tricky balance. Too much absorption and you have no force transmitted to the butt. Too little and you start tearing your stock apart. It might be something you have to determine experimentally. Alternatively, make the butt plate of your stock out of thick high density rubber (like playground rubber or car tyre or a big block of Smooth-Cast 65D or something) and modify your impact force as necessary.

 

[Frostbyte]

I wonder if i could make the entire butt and stock out of that rubber and tack the aesthetics onto it? After all i would want minimal absorpsion without risking the structural integrity, right? And yeah i plan on testing this thoroughly before going to the work of marketing it match the halo appearance

 

[RobTC]

Smooth-Cast 65D is designed to rotocast, so I would personally go that route- build the stock perfectly, then make a brush-on mould with fibreglass mother mould (cheaper than box moulding) and rotocast a hollow rubber copy. Then build your earth shaker device into that! Or don't rotocast it, but insert your outer pipe in the mould with release on it and then your stock would be a solid rubber mass with a cylindrical hole in it for your thumper. Or just cast it in place if you use threaded end caps (they're too wide to pull out of the hole, obviously, but that's also a good thing for operation) and then build the rest of the mechanics around that.

Right? Maybe. Probably not the cheapest or easiest way of doing it, but it would realistically probably be the safest and least prone to self-destruction. It depends what your R&D budget is for this project, I guess, but it definitely won't come out at $50!

Also remember that we're talking about recoil here. It exists thanks to Newton's Third Law. So if you're "firing" backwards, your spring is exerting an equal force forward on whatever it's attached to. Structural integrity sill be paramount, or you'll just end up with a gun that doubles as a maraca.

 

[Jen A266]

I like your design as its very intriguing. I will be making a Halo 3 M7 SMG with a 'realistic' kickback. i have a motor that is quite similar to a rumble motor of an Xbox controller but more powerful ad i am planning to go with it. i will add a spring and a switch near the trigger so that when i pull the trigger the motor would activate

 

[Dracosfire83]

content unavailable

 

[Frostbyte]

Smooth-Cast 65D is designed to rotocast, so I would personally go that route- build the stock perfectly, then make a brush-on mould with fibreglass mother mould (cheaper than box moulding) and rotocast a hollow rubber copy. Then build your earth shaker device into that! Or don't rotocast it, but insert your outer pipe in the mould with release on it and then your stock would be a solid rubber mass with a cylindrical hole in it for your thumper. Or just cast it in place if you use threaded end caps (they're too wide to pull out of the hole, obviously, but that's also a good thing for operation) and then build the rest of the mechanics around that.

Right? Maybe. Probably not the cheapest or easiest way of doing it, but it would realistically probably be the safest and least prone to self-destruction. It depends what your R&D budget is for this project, I guess, but it definitely won't come out at $50!

Also remember that we're talking about recoil here. It exists thanks to Newton's Third Law. So if you're "firing" backwards, your spring is exerting an equal force forward on whatever it's attached to. Structural integrity sill be paramount, or you'll just end up with a gun that doubles as a maraca.

i think that if i made an original copy, mother-moulded it, and found some kind of thicker pourable rubber to fill it and use that, i could mount the mechanism's box to it and pep or foam it from there... if i had oodles of cash to dump i would certainly test your method, as it sounds very effective, but alas... and concerning my potential maraca(hahaha), i've been trying to figure the sturdiest ways to build and connect the chassis of the gun and the best way to secure the rest...

I like your design as its very intriguing. I will be making a Halo 3 M7 SMG with a 'realistic' kickback. i have a motor that is quite similar to a rumble motor of an Xbox controller but more powerful ad i am planning to go with it. i will add a spring and a switch near the trigger so that when i pull the trigger the motor would activate

This sounds great, I'd love to see watch your progress! you should post a link

If I was attempting this I think I would use a car"door popper" mainly because when you fire a real gun the recoil is directed in the opposite direction of where the bullet is pointed.

how exactly would you rig this to work? I'm not sure i quite understand..

 

[RobTC]

i think that if i made an original copy, mother-moulded it, and found some kind of thicker pourable rubber to fill it and use that, i could mount the mechanism's box to it and pep or foam it from there... if i had oodles of cash to dump i would certainly test your method, as it sounds very effective, but alas... and concerning my potential maraca(hahaha), i've been trying to figure the sturdiest ways to build and connect the chassis of the gun and the best way to secure the rest...

Fair enough. But you see where I'm going with it, so I'm sure you can figure out an alternative that suits your budget. With the SR, the stock's basically just a box anyway, so pouring a solid rubber rectangle with a hole through it for the piston shaft wouldn't be hard at all, and then, like you say, foam or pep detail on the outside of that. Or even just HD pep the stock, support and resin like usual, then clamp it from the outside and pour the rubber directly in. It'd end up the same as my idea but at a fraction of the price- since the Pep is effectively the mould, but no silicone or fiberglass to buy. I bet the M90 would be similar. And if you use threaded rod for connections, all your pieces bolt together nicely as long as you have some method of drilling holes in stuff.

It's doable on a budget, for sure.