This is the Devtac Ronin. The company claims that this mask is level IIIA, or, to oversimplify, capable of stopping a 357 SIG or 44 magnum round.
My question is, stopping the round or not, can you even survive that level of energy transfer to your head? Wouldn't it give you a closed head injury?
People more knowledgeable than me, please discuss
so you can only get hit in the head when someone shoots accurately?
Luck plays no part in this whatsoever?
I think you would live, but the impact would turn you into a charlie carrot.
Or ya know, gunned down by the follow up shots somebody does on your disoriented now retarded cuncussed ass
I reverse Google searched it, it already exists.
Lets assume you get hit with the largest round that that mask can stop.
You already have a concussion, no doubt. The next question is if you're lucky, and the mask indented enough to break a cheekbone, or you're not lucky, and the force of your head jumping back will give you permanent neck injuries.
I'll take a broken face over a lifetime of neck pain, but the point is moot since both are preferable to being dead.
and if you wanna double down for 44 magnum
A .44magnum hitting an average human head is less of a transfer of momentum than a human head impacting something at walking speed.
Considering that you're wearing a helmet, and assuming that it doesn't deform horribly, you should be okay.
>.44magnum hitting an average human head is less of a transfer of momentum than a human head impacting something at walking speed.
LMAO let's see your math on that one I will wait
>today I learned that being shot in the head with 44mag is less dangerous than walking into a pole
>My question is, stopping the round or not, can you even survive that level of energy transfer to your head? Wouldn't it give you a closed head injury?
Sure, heavyweight boxers hit for about the same force as a .44 magnum, which emphasizes that it's all going to depend upon how well it dissipates that impact over the entire skull.
If it can actually retain its shape on the inside, it would be like getting punched in the face.
Not a fan of the edges this has.
Many spots a bullet can get a good hit/grip at instead of having a chance at sliding off.
Also the visor doesn't really give you the best of vision. Would be better with something like pic related.
To keep your neck from breaking? Yeah definitely.
To keep from getting a fucking concussion because you just got shot in the goddamn head? No.
They're both in Newtons you nigger. You should also point out that he expressed the numbers in two forms of notation too.
Guy in my company took a fist sized hunk of metal from an ied to his helmet with out penetration. He was pretty much useless the rest of the firefight and had to be med evacuated to Balance to get his head examed. Major concussion, so they sent him to Germnay to get better.
Look up brain damage caused by padded boxing gloves. Just live with your concussion mang
Tell me how KE is relevant.
Momentum is the best way of estimating what kind of "knock" it is equivalent to. Having that mask take a hit that hard, and transfer the momentum to your face PERFECTLY, is less of a jolt than walking straight into a pole.
He's not wrong. Momentum is a closed system where acceleration is assumed to happen immediately and so no energy is lost in the system. Energy can be extrapolated from momentum easily because it's just a product of mass and velocity.
A cowboy collar would go a long way to preventing injuries from hard impacts to the mask, but that's not a big threat from anything that the mask can stop. Most blows would be glancing, reducing the energy imparted from the projectile. Between that and whatever padding and extra weight you're wearing on your head, plus some support and strong neck muscles, nothing this thing can stop is likely to give you a concussion.
>Energy can be extrapolated from momentum easily because it's just a product of mass and velocity.
Not without additional information (i.e. the mass or velocity of the object in question). Momentum and energy are quite different things - you can't just pick and choose whichever one suits your argument at the moment and just ignore the remainder of physics at play.
>Bullet has momentum and energy
>Bullet hits mask
>Energy is dissipated upon (inelastic or partially-elastic) impact
>Momentum is conserved; transferred into victim's head
Momentum IS the major factor at play.
Kinetic Energy is the killer here bud. It transfers from the bullet, to the mask, to your face, and the energy has to go somewhere. The energy deposited into that small area by a .44 Magnum will fuck you up, guaranteed.
>Momentum IS the major factor at play
But that's wrong. Momentum is Newton seconds. Are you telling me if I press on your forehead with my finger for a week it's going to do the same damage as a bullet?
>It transfers from the bullet, to the mask, to your face
No, it doesn't, you fucking imbecile.
>the energy has to go somewhere.
Heat and strain energy, mostly.
Seriously, did you NEVER do the ballistic pendulum problem in high school? Inelastic collisions are a thing.
Looks lie an evil henchman type mask.
The amount of energy you are absorbing into your cranium is what you would get from being hit in the head with a bat from joe scmhoe. It is a very big concern about whether or not you will survive, you are guaranteed to at least have a massive concussion and have a decent chance of developing a cerebral edema, so better than no mask and the odds of survival are far better than if you don't have a mask but even then I would give you a fifty percent chance at most.
It would suck, but it would probably save a life. By "suck" I mean you'd get a concussion, and possibly neck injuries. In this sort of situation you'd want to be standing in such a position where your neck could move back, and where you can fall onto your back. Even just an inch or two of play would make a huge difference.
What I want to see, is if this thing would work better with an entire neck harness (like the ones NASCAR drivers do) that transfers the energy down into your legs.
A) You don't know that and
B) If it was a glancing hit or ricochet, it would be more elastic than inelastic.
>Where the fuck are you coming from.
Reality, that's where.
>OMG so traumatic, skull fracture fer sher
You fucking idiots have zero comprehension of physics in practical terms. A bullet will never transfer all of it's kinetic energy into a more massive target. It's fucking impossible, if you do the math you'd realize it'd violate conservation of momentum. Fucking lrn2science, dumbasses.
>A) You don't know that
I DO know that, because the impulse imparted on the target is still fucking tiny whether it's elastic or not.
>B) If it was a glancing hit or ricochet, it would be more elastic than inelastic.
I doubt that. You really think a ricochet is gonna come bouncing back at more than half it's velocity?
A glancing blow would have less impulse overall anyways since we're not talking +v to -v but rather a small change in direction.
The concussion isn't from a thing hitting the outside of your head, it's your brain bouncing around on the inside of your head. the force transferred into the mask is gonna move your head, whether or not the bullet penetrates it.
I think it would certainly be less than a car accident, but you'd probably want to leave the battlefield for a few minutes.
Breaking news: Bullets heat to 1100 F when shot??
short answer, no.
might theoretically save you from a .22lr at 500 yards and leave you with parkinsons in 10 years but spare your life. you watch the devtec videos and its a bunch of aspies shooting at bulletproof material in an uncontrolled environment and then exclaiming "look guys, its a success it didn't penetrate! look how cool it is!". they take no consideration of impact dispersion or deflective properties in its design. there are mesh cheek rests on the thing for christ sake. all this is is a pretty little shell to scramble your brain in. hey, at least you might have an open casket funeral.
If you can't see and can't breathe then you're pretty much dead anyway no matter how much protection you have on you. This thing looks like much more hindrance in combat than help. You'd be better off with a clear flip-up visor and standard helmet.
>Links a video of an empty helmet being shot.
Funny. That's not the scenario we're talking about. The deflection and surface area of the section of helmet being shot is significantly different to the flush face of a mask being hit.
here. Let me explain this shit to you fuckwits.
You're hit in the mask with a 12 gram bullet. It's going about 500ms. (that's a 200gr at about 1640fps).
The total momentum of this object is
500m/s x.012kg = 6kgm/s
Now, after a PERFECT ELASTIC COLLISION, a 5kg object (mass of a head) would be moving at a speed of:
6kgm/s / 5kg = 1.2m/s
Now, the average walking speed of a human is 5km/h, which is 1.389m/s. That tells us that the transfer of momentum from being hit in this mask in PERFECT CONDITIONS is still less than that of the transfer of walking into a pole, and coming to a complete stop (because shit nigger you aren't walking through that pole).
Of course, we know that bullets impacting even solid objects like steel plates don't make elastic collisions. That's why we can safely shoot steel silhouette and not die. In the case of the mask, there will be energy and momentum lost to >>28576428
heat, strain, and fragmentation of the projectile. So we know that even less than this would be transferred efficiently.
It's the same reason people can be shot by .308 in a good lined plate and not give a fuck. You're spreading out something that would normally do a lot of damage into a larger area and wasting most of the energy/force/momentum that would normally be used to damage tissue onto moving the plate and any padding behind it. And before anyone says ".308 will knock you flat!", see
https://www.youtube.com/watch?v=o5f1Fo4r4_I from 1:30
See >>28576138 >>28576053
And watch the fucking video >>28576490
As long as the energy is dissipated outside your skull and not by shredding tissue inside of it, you might be a bit rattled but you'll otherwise be fine.
That said, who knows how good this thing is at ACTUALLY stopping bullets (particularly in the ocular region).
>As long as the energy is dissipated outside your skull and not by shredding tissue inside of it, you might be a bit rattled but you'll otherwise be fine.
That was my entire issue earlier. I know what >>28576602
is sperging about, and he's right, but that is not the problem here. The dissipation and effects of the impact on your gray matter is what needs to be understood.
Won't fucking matter if you're still rendered ineffective and/or unconscious from the impact.
>The dissipation and effects of the impact on your gray matter is what needs to be understood
Are you serious?
The bullet hits the mask. It wastes a good deal of energy and momentum on getting all fucked up by strain as it deforms the mask, deforms itself, sends fragments in other directions (protip: make sure your neck is covered if you wear one of these masks), and from friction.
Then, whatever is left is transferred through the mask, to the face. This takes time, and uses up more energy; you're doing work to move the mask and compress any padding.
After that, whatever is still left is transferred first to the hair, skin and then the skull. Whatever is left after that is transferred to your brain.
And you're arguing that this is more damaging than a collision with higher momentum transfer that happens DIRECTLY to the head, with no mask or padding inbetween, which people almost always walk away from a little bit dazed and swearing at most.
Well, I guess I'm just up late then. Something about this whole idea still sounds fucking retarded but the math is there. Time to complete the stepladder like good engineers and get a youtube video put together, strap some masks on, load up some 9mm 124gr, and see how many times we can recite the alphabet before and after shooting ourselves in the face.
I am not and will not consider buying one, but no matter how hard you prepare some limp dick that has no clue what he's doing is going to fuck you up in the way you never expect. They're not going to shoot accurately, they're not going to prepare. They are just going to walk up and shit on everything you respect; that includes your training.
What? Do you not trust the math? Surely you've covered everything, right?
>someone admits they're wrong
Come on now.
I'm "momentum-anon", and as much as I'd like to "ur a faget" about it, I'm just glad that someone, for once, had a little bit of grace when they decided they were wrong on 4chan.
Yeah. I'm just off my Addy and it's been a long first week of classwork. Ironically the same shit we're throwing poo about. I just felt like something was missing the whole time, a part of the system that'd be fatal to the wearer, etc. If the math is there, it's fucking there.
Only thing I'm not seeing on YouTube are videos of people wearing this on live-fire tests, that's why I'm so goddamn critical.
>This fucking retard thinking that a bullet to this helmet is going to cause brain damage
Newton's 3rd Law
The bullet's impact will hit no harder than the recoil the shooter experiences. Unless the gun being fired regularly damages the shooter's bones and soft tissue from recoil then the person being shot wearing this helmet; provided there is no penetration, will be fine.
>Only thing I'm not seeing on YouTube are videos of people wearing this on live-fire tests, that's why I'm so goddamn critical.
Well there is atleast one video, but the gun used was a shotgun and not a slug was used.
Yeah I didn't mention deformation cuz I didn't want momentum-anon to accuse me of goalpost moving. NIJ says 44mm or less I believe.
Yeah, not what we're after. Gotta wait for someone brave enough to try a 12ga slug or something like .45/70.
No, but if you moved your finger really fast it would. You've gone and introduced impulse to the problem now.
Nope, that assumes translational energy becomes 100% heat during the firing. However, the math is correct. Purely in terms of equivalent energy only, not in context. However, during an inelastic collision a significant amount of energy might be lost as heat. Other might be lost as mechanical energy to fragment the objects.
How much does this thing run?
It's going to hurt but any damage will be minimal and comparable to the brain damage football players endure when tackled i.e. it would require many, many, many such impacts.
The word you're looking for is SHOCK or IMPACT. There's no such thing as an "impulse" TBI injury you fucking retard.
There has been ppl who been shot in the head, the bullet skid across the skull and they were fine. Humans are weird in that way...we can die so easily same time we are capable of surviving some shit.
A lot of idiotic arguments in this thread.
In Iraq I saw guys get hit in the head with shrapnel and even an errant pistol round, but survive thanks to their helmet.
Neck injury? Yes. Brain injury? Yes. But most importantly? ALIVE without permanant injury.
So in short, as a Veteran I would wear this in combat if given a choice. But it would become a hinderance as soon as it got hot.
Most common injuries in Iraq/Afghanistan
>heat stroke/heat exhaustion/heat cramps
>Wearing a mask will increase those issues.
So it has better be used in cold climates or have a cooling fan and have a way to drink water
Yes it should, are you fucking retarded? This helmet serves the same principle as all other body armour. You wear the shit in case someone gets a lucky hit on you, you cunts will semantics on every fucking thing you say.
Has anyone tried to make a climate controlled full-face helmet with an integrated port for an air supply?
Because I really can't see how you could operate in something like this mask without being smothered while you get heat stroke. Where does air get in?
>hurr itt'd knock ya right down
>cuncusshon fur shur
>whip yer head round like muh trakter tiire
How does /k/ still not grasp the concept of impacts against hard surfaces?
Why does most of this board think getting shot in a hard plate with zero backface deformation feels like anything beyond a tap?
After over a decade here, I hate you all.
But please, go on and tell me all about how some marine totally told you about the time he took an AK round to the plate and it totally like knocked him down and broke his ribs, man.
Does the rifle knock you the fuck over when you fire it?
Why don't you stick the muzzle up your asshole and try it out?
Please never breed.
>Enclave here, why isn't your video feed working?
That's not fucking enclave armor god damn it Bethesda that's the BoS armor from tactics fuck me.
If it's correctly designed there is no "energy" transfert per say, the energy is spent mostly deforming materials.
You'll have a shockwave that is dependant on the materials used and the design of the helmet. Shouldn't be massive tho, and varies with the caliber.
The only thing you can be sure of is the conservation of momentum, basicaly imagine the recoil force of the gun applied to your head. It's very low, a .44 will hit with less force than a punch, but it's not pleasant.
if it comes with a piece that can stabilize the neck you will be fine. This will stop the brain from rattling. As a boxer when we get hit its usually our head jerking that causes a concussion or knockout.
Take a 44 magnum revolver, put it against your forehead, and pull the trigger. It would be uncomfortable but not that bad.
And in case this isn't obvious, face the muzzle away from your head.
>this will stop the brain from rattling
First off, you're dead wrong.
Second, you're still dead wrong. The force of a bullet impact that fails to penetrate is going to impart FAR less force than required for any sort of injury. In fact, it would hardly even move your head at all.
THIS THIS THIS THIS
If it doesn't BREAK YOUR FUCKING HAND/ARM/SHOULDER/DICK to fire it, the projectile isn't going to somehow MAGICALLY GAIN MORE ENERGY until it impacts something.
Do you think the recoil of a handgun is enough to give you a concussion? Because the force of it impacting something is going to be less than that, unless your projectile is magically gaining energy as it travels.
How am I dead wrong? You dont think when an object hauling ass hits you your body isnt going to jerk in some manor. Let me put a helmet on you and punch you in the face your neck will still jerk back. Lmao confirmed for never playing contact sports.
Is it? Is it really, faggot?
Go watch the fucking videos of the wops taking 7.62x39 to the chest plate at less than a foot, without hardly a flinch.
Because you are fucking dead wrong.
This isn't a fucking safety laying you the fuck out. This is a relatively light projectile impacting a relatively broad surface that it fails to penetrate or dent. The entire fucking plate takes the force of the impact, which equates out to be fuckall for felt impact.
The impact from 7.62x39 to a hard plate is SUBSTANTIALLY less impact force vs a human fist thrown by even a complete non-fighter.
Does a .45 derringer blow your hand apart and break fingers and shit?
So WHY THE FUCK would you think that same round is somehow capable of giving you any sort of head injury?
>Object travels and hits solid object that is attached to movable appendage.
>The forward energy hits solid object causing the energy to spread and disperse it still has forward moving potential.
>The appendage takes some energy as its distributed through the mask (similar to how you take the energy from a cars speed, weight, etc in a car crash)
>Whips neck back causing brain to rock
Physics 1 & 2
You know what happens when a bullet hits a vest plate? It causes impact and force and knocks you off your feet. In cases causing broken ribs and internal damage. Lmao I cant believe people are this stupid.
With the Crye Chops, you get protection against 2-4gr fragments moving 1000fps faster than the Gunsite mandibles. 200 more fps against 9mm, and unlike the mandibles, has level IIIa protection against .44 magnum. It also costs $260 vs $456.
>You know what happens when a bullet hits a vest plate? It causes impact and force and knocks you off your feet. In cases causing broken ribs and internal damage. Lmao I cant believe people are this stupid.
I can't believe retards still believe this meme
When a bullet hits something the energy spreads thats the point of the plates. When energy disperses it can still cause damage. Ask any vet who has been hit while wearing a vest how it feels. And the vid is the same concept small plate small cal. still injury. Are you this retarded srs.
>le insult while i post anime pics from mummys basement
>Doesn't even knock him visibly at all
>Deformation of the vest causes point-injury and bruising
>He flinches from the pain half a second after impact
Suuuuure, nice "proof."
if shooting those guns won't break your wrist, taking the bullet won't break your neck.
You might hurt your neck temporary, but the mask is not bolted to your face, impact would tear it off and transfer energy in many directions including your face.
Bullets don't fucking get random energy during their travel, they lose it. Quite fast.
Your head moves on a neck and your mask wiggles on your face.
As long as your head is not bolted down and the mask bolted down on it with 0 wiggle room, you'll propably end up with a black eye or a broken nose and sore neck at worst.
Shell casing does not even cling when it hits the ground.
Gonna go with the people who came into medic after being hit with broken ribs and internal bleeding.
U LIAR U WRONG
But I have seen it
NO LOOK LE VIDEO FROM YOUTUBE DAT COULDNT BE ALTERED
But in combat they get shot they have issues
SHUT UP YOU POOP
Back 2 reddit
To be fair, blunt injuries and broken ribs can still occur if the plate is sufficiently deformed or spalls. But it's not a concussive injury like the fudd-tier retards in this thread are parroting.
just cause you're in the army doesn't mean you understand how your equipment works.
Being in the army just means you didn't get into higher education.
Civillian specialists in many cases know better than the avarage grunt on the ground.
You're confusing soft armor with hard plate armor. Soft armor needs to deform in order to capture the bullet, which can cause blunt trauma. Hard armor tends to not deform when stopping a bullet, so blunt trauma isn't a problem.
GOD DAMN you're fucking stupid. The amount of momentum something has is completely different from how "dangerous" it is.
A fucking Honda Civic rolling along at 1 mph has THOUSANDS of times more momentum than a .44 magnum. That doesn't mean it's going to kill you when it hits you does it dipshit?
The best defense is not getting shot. But how do you do that? By staying in school, you dummy.
The Honda civic is more deadly, but because its so slow you can move out of the way.
The bullet is less deadly, but going so fast that your body cannot get out of the way.
More momentum = lethaler
>implying he wasn't wearing a trauma pad
There is a difference between an impact on a hard plate with zero deformation (which is the worst case scenario when considering shock trauma) transferring to a torso, and the same impact transferring its energy in a trauma plate, then a torso.
>Does the rifle knock you the fuck over when you fire it?
Again, it's shock mechanics, and absorption over distance and time. The rifle doesn't knock you over, because you are movable in space. It pushes your shoulder as it travels backwards.
If you were to put your shoulder between a high-caliber rifle and a non-deformable wall, it would be crushed.
The reason marines don't get their ribs broken is because they have a trauma pad, or standalone plate to absorb the shock. In the case of the mask, if there is no deformation, all that energy is directed towards a momentum gain for the mask and your head. The problem is that your head+mask has little mass, and thus requires little inertia to move, while your torso does. Your head will be pushed violently, while your torso won't. Consequentially, your neck would get wrung, which can cause a lot of damage.
Getting shot in a plate won't knock you down, but it can cause shock trauma if it's not properly absorbed. It's way more than a "tap".
You know the force you feel when you shoot? That's the force with which the bullet comes out of the barrel....equal and opposite reaction and all. Of course, that force is imparted on a much smaller object when talking about the bullet, but that doesn't change they fact.
If the recoils from a would e enough to knock you out if you had it up to your head, then you would be right. But you're not.
Ninjaneer here. Let's do some MATH, NIGGAS!
Let's call our .44 magnum a 250gr bullet at 1,600 fps.
That's p much 1.2 grams at 488 m/s. This gives us roughly 143 joules of energy.
According to google, the average human head weights 5kg. Going the other way, that gives us a velocity of 7.6 m/s. Assuming this energy is transferred in .1 seconds (it'd be less), that's 76 m/s^2.
That translates to 7.75 G's.
According to https://en.wikipedia.org/wiki/G-force an average human can take 5 Gs before losing it. According to http://www.braininjury.com/injured.shtml you can take between 10 and 50 Gs without getting brain damage. The varies from person to person, obviously.
So, in conclusion, you'd survive it, more than likely. You probably wouldn't even have brain damage. You MIGHT pass out, though. Probably not enough duration, TEE BEE AYCH, FAHM. It'd hurt like motherfucker but you'd be alright.
>As long as your head is not bolted down and the mask bolted down on it with 0 wiggle room, you'll propably end up with a black eye or a broken nose and sore neck at worst.
Plus fucking 1. This thing could definitely work. Whether or not it's worth the weight and the potential respiration/perspiration issues is a separate concern.
It won't, retard. Do you understand basic physics?
Armour works by distributing the energy of the projectile evenly over a large area, preventing penetration. You're only feeling the same energy as the recoil of the weapon (a little less, actually). That isn't going to fuck you up.
MD/PhD in trauma/emergency medicine and 15 years experience as first responder in large city here.
Depends on padding like trauma pad shit discussed above. Impulse (F*t) into shooter's shoulder and your face is the same, but force felt is dependent on how long total momentum transfer takes. Padded shit = takes longer = less force felt. Total force = P*A, so what you mentioned is pressure. High pressure and short times kill. This is what leads to hydrostatic shock inside of you that is actually damaging. Another post above talks about Gs, which is simply just acceleration. This isn't correct because we are virtually continuous "fluid" mass. What's better is to think about the fluid acceleration (basically waves) inside of people. The whole head won't have the same G acceleration and the reason why people survive such high Gs is because WHOLE head accelerates. What makes bullets more brutal is that brain tissue regionally accelerates differently as shock wave moves through (i.e. being in a swell on an ocean wave makes you accelerate more than being in the top or trough).
This is what tears tissues, makes you have brain bleeds, etc.
I explained why it was wrong above. Basically, fluids accelerating and solid mass accelerating are different beasts. Most medical problems due to gunshots and trauma are due to fluid "shockwaves" moving through sensitive tissue.
To clarify, imagine the differential compression and expansion of brain tissue as shockwave moves through. This literally tears the tissue, compared to simple acceleration which only compresses the WHOLE body. This isn't as dangerous, although it's still very bad.
Well sure. I mean, we could have gone WAAAAY further with the math. We could have done fluid mechanics and rotational inertia but shit, man. It was just a basic calculation with real numbers. The physics and math were still sound.
If someone would like to do a more complete analysis and demonstrate the math, I'll sit here and wait.
Engineer here, I'll answer.
>Assuming this energy is transferred in .1 seconds (it'd be less)
If it's less time to absorbe the energy, it's more Gs.
If it's more Gs, it's dangerous.
You got the logic backwards, you retarded engineer.
This thread has way too much discussion about bullets hitting your head
If you did get shot in the head, would you rather be wearing this or just get shot in the head?
It's a "no brainer".
I don't think the main idea of this is to protect you from getting shot in the head though. It MIGHT save your ass, but even helmets get penetrated by certain calibers.
What it would be good for (and what most eye protection is designed for) is for saving your ass from getting hit with shrapnel/spall/fire/etc.
Basically anything that could fuck your world up on a battlefield that is not a bullet. I think this mask would be pretty shit for dismounted infantry.
It might actually be good for vehicle crew members though, particularly light vehicles that are most likely to sustain damage resulting in shrapnel/fire getting in the crew compartment.
If I had to ride around in an MRAP or something similar in a war zone, and I had the option of wearing this, I probably would. Would take it off and stick with a normal helmet outside though, it would get in the way too much on the ground.
Yeah, no shit. I also didn't hold that many decimal places. I was doing calculations off the cuff. If you'd like to find the length of a .429 in bullet and the time it'd take for that length to travel from nose to tail, be my guess. I didn't make any statements about change in velocity over a change in time. So please, point out to me where my logic is backwards, you unemployed engineer.
I just explained it to you, fucktard. The energy is transferred in much less than 0.1s. That means that the Gs are HIGHER.
Purposefully overestimating the time it takes for the shock to be absorbed severely underestimates the amount of Gs. Thus, this renders your calculation invalid, because you didn't take the "worst case scenario". You thought you were being conservative, but you weren't.
You didn't prove shit.
No. Fucking. Shit.
I didn't say it'd be more or less. I didn't say it was the worst case scenario. I didn't say anything about it other than it'd take less time than I used for my off-the-cuff estimation.
Are you a first year student or did you just go to school in Arkansas? Maybe you are just a cousin of Dr8co and need me to do this in Spanish for your inbred ass.
Let's go with 0.81 inches since that's what I pulled up quickly for a goddamn 220 grain round. That's 0.0675 feet since you obviously can't do the math seeing as I gave you the opportunity to do the math and prove me wrong.
Now, please go ahead and finish up with the kinetic energy and acceleration equations and show us all how good you are. Let's see the massive difference in acceleration that 250 grains transfers to a 5kg mass in a much smaller time frame.
That's the point. Not only are they better, but the chops don't make you look less like cyborg ninja and more like a real human bring.
Good fucking lord. I knew the MTEK sturdy models were supposed to help you survive a gunshot to the face, but I didn't think it would have looked that fine. Granted, the dude looked like he was very well braced and the energy was absorbed fairly well, but still, holy fuck.
>not wanting to be a cyborg ninja guntruck gunner
/k/'s resident airshitter here
Devtac Ronin makes these masks, literally, for Airsofters. They then added the NIJ rating for shits and giggles to justify their obscene price.
The mask, all things considered, is really made well with good retention straps. It has fans to circulate the air inside the mask, preventing fogging and keeping your face cool.
Why it's a dumb idea - It doesn't cover the entirety of your head. Your rear is completely exposed. So rounds or shrapnel coming from behind will still fuck your day up unimpeded. Also, as mentioned in the thread already, the mask has a lot of grooves that would prevent a bullet from deflecting properly and instead would just transfer the energy into the mask.
Otherwise the idea isn't flawed or super keyboard commando. It just seems like a helmet with the typical GIGN style clear plexiglass mask is better overall - which is the system I would choose if I ever had a choice.
Pic related - Taiwanese army with their ballistic face masks
>UCP Helmet cover
>1 hole nvg shroud
>someone went to the trouble of installing some sort of rail system, which doesn't host accessories, lights or other cool shit - but instead it holds some dumb face mask
That guy better be some sort of door / roof gunner or some shit
>You know what happens when a bullet hits a vest plate? It causes impact and force and knocks you off your feet. In cases causing broken ribs and internal damage
jesus christ are you kidding me nigger
>guy getting shot point blank with an FAL, standing mostly with only one foot on the ground for demonstration
>"It really didn't feel like much. Much less than a punch."
Did you even read my explanations? Your physics weren't sound in this context because it's not a solid body accelerating and you have to consider continuous deformations of the brain. If the head was a solid ball, then your physics is sound.
I'm saying you have to consider your brain/soft tissue as a soft fluid mass compressing and expanding rather than thinking about it as a solid ball that is moving uniformly.
There's also nothing to do with rotational inertia in this case unless you're mentioning the torque due to bullet hitting or bullet spin, which is a SUPER minor effect compared to brain being forced to be the medium of high energy waves.
Read and think before you talk.
>I didn't say it'd be more or less.
>I didn't say anything about it other than it'd take less time than I used for my off-the-cuff estimation.
>I didn't say it was the worst case scenario.
And yet you used it to somewhat explain that there wouldn't be damage.
>Do the math for me
Jesus Christ, you should be ashamed of calling yourself an engineer. I’ll play tag. You wanted to prove that it couldn’t do damage. I’ll prove that it can take damage, even with damage-minimizing assumptions.
Since a G can be approximated to 10 m/s^2 (it's 9.81) I'll use metric.
From this video, it is visible that bullets that deform on impact are not significantly slowed down as they are deforming (probably soft points, which is a damage minimizing assumption, since a hard bullet wouldn’t absorb as much energy through its own deformation). Thus, from bullet length and impact velocity, we can estimate the time it took for the bullet to transfer it’s energy to the mask.
While it is true that the bullet deformation removes quite a lot of that energy, I’ll just ignore it for now, and remove some of that energy later.
Overall length is 41.89mm, case length is 32.64, thus the part of the bullet that protrudes is 9.25mm. From related picture, I’ll guesstimate that the rim-to-tip length is about a third of the overall bullet length. Since it’s approximate, I’ll just say that the bullet is about 30mm long.
I’ll start by using your own numbers (1600 FPS or about 488 m/s), and with a 250 gr (or 1.6 gram) bullet. Since the velocity is still reduced at impact, I’ll say that the velocity is 1400 FPS (or 426 m/s). This gives a kinetic energy of 1450J. Recall that the bullet deformation takes some lot of that energy, so I’ll conservatively assume that the energy transferred to the mask is only 700 joules. Assuming a 5kg mass, this kinetic energy translates to a ~8 m/s velocity.
>tfw people on /k/ try to out physics professor each other while not understanding something as simple as joules
From someone who has actually taken a bullet to the helmet, everyone is full of shit
> It just seems like a helmet with the typical GIGN style clear plexiglass mask is better overall - which is the system I would choose if I ever had a choice.
Hell, the Polycarb they use in ballistic eyewear can stop a 12g 00 pellet, that's more than good enough for full-face protection considering a kevlar helmet can't stop rifle rounds either.
Maybe shift to a skullbucket like this that integrates a hud for NETT Warrior or whatever it will be called, and the battery can run a low-power ventilation system and modular earpro/radio headset, all either integrated or connected via a single coil cable to a low-profile pack.
The bullet isn’t entirely deformed, the base is still there on impact, so the travel the bullet goes through as it is deformed isn’t the full 30mm. Assuming 20mm of travel at 1400 FPS (or 426 m/s), the bullet transfers all of its energy within 0.02/426=4.7E-5 seconds.
That’s pretty low, but you can check this paper to verify that it’s indeed the correct order of magnitude.
Thus, assuming we have that 5Kg mass reaching a 8m/s velocity in 4.7E-5 seconds, and acceleration being velocity change over time, we get 10/4.7E-5=170 000 Gs. Is that unrealistic? The wikipedia page for G force indicates 190000Gs for a 9mm Parabellum for peak acceleration in the barrel (and 60 000 Gs for average along the barrel, but that’s over a longer distance and time, so it’s much lower than the shock we are considering). Again, I’ll be nice, and assume that the final velocity isn't 8m/s but 5m/s. That mask is experiencing at least 100 000 Gs. Since the mask and a human head aren't solidly linked, and since the mask will take additional time and travel to transfer the energy to the head, I'll be EXTRA NICE, and remove 3 orders of magnitude.
That's still 100Gs. (Which is survivable if it's a peak acceleration, with a very lucky person)
So you can take those ridiculous orders of magnitude of yours and shove them deep in YOUR ass before you call yourself an engineer again. My numbers are probably wrong, because of a lot of assumptions, but at least I got the physics right. A bullet impact, nor it's consequential acceleration to a human body part, is nowhere near 7Gs.
I'll let bio experts deal with the energy transfer from the mask to the head, then to the brain.
>I’ll start by using your own numbers (1600 FPS or about 488 m/s), and with a 250 gr (or 1.6 gram) bullet. Since the velocity is still reduced at impact, I’ll say that the velocity is 1400 FPS (or 426 m/s). This gives a kinetic energy of 1450J.
1.6 grams... 426m/s... you think this is 1450J. Really? REALLY?!
ONE HALF FUCKING M V SQUARED AND YOU THINK ZERO POINT ZERO ZERO ONE SIX KILOGRAMS TIMES FOUR HUNDRED TWENTY SIX METERS PER SECOND IS OVER FOURTEEN HUNDRED JOULES?!
That's it. I fucking quit. I'm not doing this any more. You're not even trolling. I'm going to fucking bed. You make me ashamed that I even read this site. You're not an engineer and you can't do simple math.
I hope you step on a Lego.
My bad, calculator typo, missed a zero.
Assuming that the impact removes about half to that energy, that's 70 joules.
70 joules of kinetic energy to a 5kg mass yields 2.64 m/s.
Assuming the same time scale (4.7E-5), you get 2.64/(4.7E-5)=36170 Gs.
I missed a zero, but you missed physics, and you're still a retard.
FFS, it's getting late and I keep fucking up my math.
145J, assuming deformation takes about half, that's 70Joules, which yields 5.29m/s of velocity with a 5Kg mass.
Finally.. Jeez, fuck doing math on a Sunday evening.
But that is not how it works fagmaster, when you shoot a gun the energy is transferred over a greater length of time. When you get shot the energy is transferred nearly all at once.
It's very possible your neck could end up broken.
36,000 Gs. That's your final answer? Again, I'm the second guy, not the one you were arguing with but you think a 44 mag round dumps 36,170 Gs of acceleration into a human head. Yeah? That's where we're going? Lol, k.
Holy shit, you dumb niggers are STILL arguing about this?
>70 joules of kinetic energy to a 5kg mass yields 2.64 m/s.
>Momentum magically appearing out of nowhere
Looks like YOU'RE the one missing physics, pal.
Momentum HAS to be conserved. Period. So unless the helmet is made of explodium causing a hyperelastic collision, with the bullet bouncing away from the impact with twenty times the velocity it had before the impact, there's no fucking way that it's going to knock a 5 kg head to 2.64 m/s.
Well, there are a lot of assumptions, like the mask being non-deformable and non-movable, which is a huge assumption, because it'll make the Gs skyrocket.
Assuming that the mask moves only 0.5cm, and that the head, in turn, moves like only 1cm would reduce the Gs quite a bit. Physically, I'm expecting far lower values, but nowhere near 7Gs for the mask. That's ridiculous.
I didn't conserve the 145J of momentum, because I assumed that the deformation of the boulet would consume some of that energy.
The calculations are otherwise correct (corrections included, of course)
>The calculations are otherwise correct (corrections included, of course)
Great, you (eventually) made correct calculations of a physically-impossible scenario. Congratulations.
Now try again, taking conservation of momentum into account.
I have and if I had to go through work and type it out and explain it like you did I would catch it unless incredibly drunk of tired. Go to bed, you have remedial Algebra tomorrow.
>Still working in Joules after I directly told you that MOMENTUM must be conserved
You literal fucking retard.
>426 m/s * 1.6 g = 0.6816 Newton-seconds of momentum
This MUST be conserved within the system. Mechanical energy (i.e. your precious fucking Joules) may or may not be conserved, but momentum ABSOLUTELY MUST be conserved.
>Inelastic case: Bullet embeds in helmet
>Final velocity of head+helmet+bullet: (0.6816 N-s)/(5001.6 g) = 0.1363 meters per second
That's IT. In an elastic collision (i.e. when mechanical energy IS conserved), the velocity of the head would be just under twice that, and MOST of the kinetic energy would be carried by the bullet bouncing away at over 400 m/s. But for YOUR result, in order for *momentum* to be conserved, the bullet would need to have a final, post-bounce velocity of (negative) SIXTEEN THOUSAND, eight hundred and fourty(ish) meters per second. And as you can imagine, having the bullet bounce back with that much velocity would require a metric fuckload of energy manifesting out of thin air.
>I had to go through work and type it out and explain it like you did I would catch it
I missed the mistakes exactly because I had to write all that crap, juggling between my scribbles, my calculator, and my keyboard.
Not that I'd not make mistakes in a more favorable environment, though.
Regardless, the calculations go like this:
=>Bullet velocity and mass
=>Bullet kinetic energy
=>Impacted body mass + distance/time to absorb bullet kinetic energy
If anyone has better assumptions or a better method to estimate shocks I'm all ears.
>In an elastic collision (i.e. when mechanical energy IS conserved)
Sorry, tired. I was fixating on keeping kinetic energy, since conservation of momentum would imply no bullet deformation.
Ok, if I keep momentum, then bullet momentum is 0.0016(Kg)*426(m/s)=0.68 Kg.m/s
With a head of 5 Kg , conservation of momentum would yield 0.13 m/s.
If I choose conservation of momentum of conservation of energy, the head will reach a velocity of 0.13m/s.
If I keep the assumption that this occurs in 4.7E-5, then the G forces are 2765Gs.
Still pretty high.
Though I recognize the interest of momentum over kinetic energy since it you can neglect bullet deformation.
>Sorry, tired. I was fixating on keeping kinetic energy, since conservation of momentum would imply no bullet deformation.
Nevermind, this is bullshit.
Elastic=conservation of kinetic energy
Inelastic= use momentum
Hard to say, because we don't know how much the mask will absorb, and how the masks and head move on impact. You'd actually have to put accelerometers on the mask and head, which is usually the industry's standard to measure shock.
I'd say the bullet has more than enough oomph to hurt you through impact alone (no penetration), but won't if the mask absorbs it very well. Plus, the brain is also protected through watchamacallit-fluid-stuff in your skull.
This is like 2010 to 2012 OIF. A lot of the senior line platoon soldiers in my old troop got a whole bunch of them to fuck around with as truck gunners. Couldn't actually use them too often because of how hot and heavy the first gen of MTEK faceguards were. They ended using them as sweetass batting cage helmets with their batting machine though.