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Nerf Rocket Cracked a HUMVEE Window!

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NERF ROCKETS CAN BE LETHAL!! This video from Amped Airsoft showed that they still can crack a BULLETPROOF (correction: REGULAR; the assessment and recommendation below still stand) HUMVEE window: https://youtu.be/GN5yIXOoiNQ Just imagine if it hit a player!

 

So how could this happen? Kinetic non-lethal weapon studies have shown that although the materials of the projectiles affect their blunt trauma injury potentials, the COMBINATION of the projectile mass and its impact velocity and impact area has stronger correlations with the level of injury induced. [Lyon, 1999; Koene, 2008] In this case, the combination of the mass of the Nerf rocket and its impact velocity and impact area may be too much for the HUMVEE window. Since Nerf rockets have been used without similar incidence in the past, their mass and impact area are likely not an issue. The only possibility left is that it was flying too fast and the launcher was shooting too hot.

 

Since this incidence showed that Nerf rockets can also be destructive, we may need to re-examine the rules and their enforcement regarding use of large caliber projectiles in both Airsoft and paintball games. From what I can gather from the webs, the common 230 fps limit for Nerf rockets was based on anecdotes. There are many scientific studies on kinetic non-lethal weapons, and we should consider them when making rules. In non-lethal communities, 44 mm indentation on ballistic clay is commonly used as the failure criterion (i.e. lethal potential). The ballistic clay is difficult to prepare, but it is possible to use energy density (energy per impact area; J/cm^2) to estimate the indention on ballistic clay. [Lyon, 1999] I will present the estimated indention on ballistic clay for a 32 gram 2-in Nerf Rocket shot at 230 fps (maximal velocity limit for Nerf rocket in most events) and 150 fps, a 3.5 gram 0.68-in paintball shot at 230 fps (typical limit), and a 26 gram TAGinn projectile shot at 150 fps. Given a 32 gram 2-in Nerf rocket fired at 230 fps, the energy produced is 78.6 J, and the energy density is 78.6 / (pi * (2.54^2)) = 3.88 J/cm^2. The estimated indentation is 12 mm. Given a 32 gram 2-in Nerf rocket fired at 150 fps, the energy produced is 33.4 J, and the energy density is 33.4 / (pi * (2.54^2)) = 1.6 J/cm^2. The estimated indentation is 2 mm. Given a 3.5 g 0.68-in paintball fired at 230 fps, the energy produced is 8.6 J and the energy density is 8.6 / (pi * (0.86^2)) = 3.7 J/cm^2. The estimated indentation is 10 mm. Given a 26 gm TAG projectile fired at 150 fps with 400 psi of CO2, the energy produced is 26 J, and the energy density is 26 / (pi * (1.85^2)) = 2.56 J/cm^2. The estimated indentation is 6 mm. They are all below lethal threshold, and given the indentation caused by Nerf rocket shot at 230 fps is similar to that by paintball, it may seem the 230 fps limit is acceptable. However, this model assumed that the projectiles were hitting the torso area. The torso area can usually take more punishment because it contains great amount of muscle and fat tissues, while the head area is more susceptible to injury because of its thin surrounding soft tissues. Studies have shown that facial bone and skull facture can occur above 40 J.[Clemedson, 1968; Schneider, 1972]  Since the head area contains many vital organs, its protection must be considered when making rules for Airsoft or paintball games. Given 40 J as the maximal acceptable energy for Airsoft or paintball projectiles and a 32 gram 2-in Nerf rocket, the maximal acceptable velocity is SQRT (40 * 2 / 0.032) = 50 m/s (164 fps).

 

Below is my recommendation based on my literature review:

  1. Large caliber projectiles for Airsoft or paintball games should have maximal energy of less than 40 J. For Nerf rockets, the maximal velocity should then be less than 164 fps. For TAGinn projectiles (Pecker, Paladin, Reaper, and Archangel), the maximal velocity should be less than 180 fps.
  2. Large caliber projectiles for Airsoft or paintball games should also have maximal energy density of less than 3.7 J/cm^2
  3. Minimal engagement distance (M.E.D.) for large caliber projectiles should be 50 feet for additional protection as well as realism. Typical arming distances for 40-mm grenades range from 46 to 92 feet.
  4. Referees should carry chronographs to spot-check launchers on the field just as many have been doing for Airsoft guns or paintball markers.
  5. The hardness of the projectiles has little effect on safety. Legalize TAGinn projectiles (at least non-pyro ones)

 

REF:

  1. Lyon, D.H., Bir, C.A., Dubay, D. “Inury Evaluation Techniques for Non Lethal, Kinetic Energy Munitionsâ€, Army Research Laboratory, Aberdeen Proving Ground, Report # ART-TR-1868, Jan 1999.
  2. Koene, B., Id-Boufker, F., Papy, A. “Kinetic Non-Lethal Weapons†in “Netherlands Annual Review of Military Studiesâ€, 2008
  3. Clemedson, C., Hellstrom, G., Lindgren, S. “The Relative Tolerance of the Head, Thorax, and Abdomen to Blunt Traumaâ€, Annals New York Academy of Sciences, Vol. 152, 1968.
  4. Schneider, D.C., Nahum, A.M. “Impact Studies of Facial Bones and Skullâ€, Proceddings of the 16th Stapp Car Crash Conference, November 1972

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Just got words from Amped Airsoft (the HUMVEE owner): It's a regular window. However, my assessment and recommendation still stand. The aims of this thread are: 1) Raise awareness of blunt trauma prevention in Airsoft or Paintball, 2) Dispel the wrong notion that a soft and spongy projectile is safe at whatever velocity. In contrast, A hard but light projectile can be safely used in games with proper regulations and protection.

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This is not a knee jerk reaction. There are lots of discussion by Paintball Nerf-users to reduce the maximal velocity from 230 fps to around 150 fps. They reported that there are instances when players had their masks knocked off or got the wind knocked out of them at 230 fps.

 

Milsimlabs (https://www.facebook.com/MilSimLabs) also shares the same view, which is quoted below:

 

"There's no voodoo here, all the work has been done, but many game hosts don't chrono or don't have limits... and people are shooting them beyond the limits used for non-lethal weapons. From my note book: "a study by the US army on blunt force trauma lists 40.67+ joules to be “dangerous†i.e. “broken ribs, concussions, loss of the eyes or superficial organ damageâ€. 122+joules is listed as “Severe Damage†i.e. “massive skull fractures, rupture of the heart and kidney, and fragmentation of the liverâ€
http://www.irishnationalcaucus.org/some-examples-of-human-rights-abuses-in-northern-ireland-the-use-of-plastic-bullets-and-strip-searches-of-women/ “Within the non-lethal community, it is generally accepted that any impact exceeding 58 foot-pounds(78.6J) of kinetic energy: will result in a potential fatality.†http://www.thefreelibrary.com/Engineering+the+nonlethal+artillery+projectil.-a0103384465

Nerfs pocket vortexes weigh in @ about 32-34 grams.. it depends on the batch of foam. Breaking it down:
@ 96 FPS it can cause a facial fracture (assuming no protective head gear)
@ 160 FPS crosses in to “dangerousâ€
@ 222 FPS its potentially fatal
@ 277 FPS it can rupture internal organs and fracture the skull.
People might want to re-think the 220fps limit on Nerf some events use on direct fire weapons."

Here is 150fps (33j) vs a double wall shipping box


you can imagine what happens when people are shooting double that muzzle energy?"

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I am sure this doesn't change your well prepared report, but the Humvee windshield in Amped's Humvee is not ballistic glass. It is standard automotive DOT glass. I have personally inspected the documented damage and I also acquired the replacement glass for this same vehicle. Thank you for your findings and I hope in turn this will lead to perhaps a rule set on technical's pertaining to an impact shield of sorts for vehicles without ballistic rated glass. Thank god for hold harmless waivers. 

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I thought Taginn rounds are listed as allowed for AMS game play. 

Rule set;

APPROVED PYRO GRENADES

This section is based on our experiences with pyro devices.  If you have a device that you would like approved, AMS staff needs to physically see the device perform in order to approve it.  Please contact AMS to arrange this.

TLSFX Pea grenades

TAG R2BS Grenades

TAG Archangles, Reaper, Peckers

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I'm cool with keeping the sport safe, granted these are military simulation style events. That's why rule sets are designed to govern players actions, if someone is being shot with these launcher weapons two questions must be asked. Is the shooter completely aware of his environment there for responsible for his shot. And the player hit by said round was he aware of his environment. Situation awareness, come on people, if you want free for all back yard BS, then save your money and our time and stay home. When tragedies like these listed above happen hold the parties responsible. Suspend players, hell put a fine on it, Every player has a responsibility to themselves and the player next to him to honor the rule set and that is a simple reflection of the game play in true Military scenarios. Everyone may at one time be new to MilSim but for heavens sake stupidity and reckless behavior is not new to anyone.These actions are what we should be looking into how we can govern more closely. The damage to game play vehicles can be negated with proper preparation and clear observation of current rule sets. 

 

In closing remember who and what, us as players, are trying to emulate. We must police our own ranks and lead from the front. If this can not be accomplished then everyone should grab a history book and study up. I have never heard of or seen anyone man win any war.

I look forward to seeing many of you at Faded Giant 4, Travel safe and lets enjoy ourselves with close friends in arms, Friend or Foe

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just in case its unclear, the shooter is always responsible for his shots. I'm referring to blind lobs and quick shoots that should have never been taken. In those cases the shooter should be charged to the full extent of applicable law.  

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This is not a knee jerk reaction. There are lots of discussion by Paintball Nerf-users to reduce the maximal velocity from 230 fps to around 150 fps. They reported that there are instances when players had their masks knocked off or got the wind knocked out of them at 230 fps.

 

Nerfs pocket vortexes weigh in @ about 32-34 grams.. it depends on the batch of foam. Breaking it down:

@ 96 FPS it can cause a facial fracture (assuming no protective head gear)

@ 160 FPS crosses in to “dangerousâ€

@ 222 FPS its potentially fatal

@ 277 FPS it can rupture internal organs and fracture the skull.

People might want to re-think the 220fps limit on Nerf some events use on direct fire weapons."

 

Here is 150fps (33j) vs a double wall shipping box

you can imagine what happens when people are shooting double that muzzle energy?"

 

If players report they had "masks knocked off and wind knocked out of them" then how would a reduction of 8FPS result in a fatality?  I understand the latter is specifically concerning the nerf pocket vortex (~33g), but what was the base model for the previously mentioned report?  If similar, then you need to revise your breakdown.

 

I'll read the rest in a few days.  Very interesting post.  Aren't math and science fun?  

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Guest Specs

A great write-up for sure, and important considering how many home-made AT devices we are seeing at AMS events these days. 

 

Aren't teams currently required to pass HW's through admin approval like you would homemade IED/Tripwire mines and such? In the very least there should be some kind of impact test that needs to be passed at chrono. 

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I am 100% certain that this has more to do with the properties of the result of ANYTHING AT ALL HITTING FLAT glass than it does the sudden magical powers of Nerf products.

 

Trust me, I have replaced windshields on plenty of my military trucks as a result of impacts over the years, you would be surprised what will crack a flat windshield.

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I am 100% certain that this has more to do with the properties of the result of ANYTHING AT ALL HITTING FLAT glass than it does the sudden magical powers of Nerf products. Trust me, I have replaced windshields on plenty of my military trucks as a result of impacts over the years, you would be surprised what will crack a flat windshield.

 

Don't ruin this thread with your logical observations.  Charpy testing is for squares.

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Oh, I know, far be it from me to interfere with our resident chicken little telling us the sky is falling.

 

After the TAG thread, I am just waiting for him to disclose in what manner he has a financial stake in defaming NERF...

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Oh, I know, far be it from me to interfere with our resident chicken little telling us the sky is falling.

 

After the TAG thread, I am just waiting for him to disclose in what manner he has a financial stake in defaming NERF...

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Oh, I know, far be it from me to interfere with our resident chicken little telling us the sky is falling.

 

After the TAG thread, I am just waiting for him to disclose in what manner he has a financial stake in defaming NERF...

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Oh, I know, far be it from me to interfere with our resident chicken little telling us the sky is falling.

 

After the TAG thread, I am just waiting for him to disclose in what manner he has a financial stake in defaming NERF...

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Oh, I know, far be it from me to interfere with our resident chicken little telling us the sky is falling.

 

After the TAG thread, I am just waiting for him to disclose in what manner he has a financial stake in defaming NERF...

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Oh, I know, far be it from me to interfere with our resident chicken little telling us the sky is falling.

 

After the TAG thread, I am just waiting for him to disclose in what manner he has a financial stake in defaming NERF...

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It's basic projection.  Not once is the impact resistance listed in the OP or followons.  I'm also curious where you got the FPS for the nerf in the Milsim Labs video - I cannot find it listed anywhere.  Their AT launcher was coming in at around 75FPS, where in the video they were testing a mortar launcher.  

 

Here are my recommendations:

 

1) Look at ALL of the variables when you list calculations.  I can twist math to show all kinds of terrifying things about airsoft, but they are completely irrelevant when you look at the big picture.

 

2) Tell us what your angle is.  Obviously you have a hardon for TAG projectiles - this is why, but don't try to leave us in the dark.

 

3) Learn what BFD is... you list it repeatedly, but never actually use the acronym, which is really, really odd.  I've worked ballistics before and it's one of the more common testing criteria.

 

4) Organize your post.  No one wants to read a paragraph full of equations.  Read a few papers and list your math in the following order:  Explain the basic variables, explain the derived variables, show the equation, list either the variable table or throw them in the equation.

 

5) Look up the impact resistance of automotive glass.  It took me appx 30 seconds.  Range is 29-49 J for concrete and steel.  I'll plot these out in a bit so we can project estimated nerf mass vs energy.

 

6) Don't abandon your thread.  

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I thought Taginn rounds are listed as allowed for AMS game play. 

Rule set;

APPROVED PYRO GRENADES

This section is based on our experiences with pyro devices.  If you have a device that you would like approved, AMS staff needs to physically see the device perform in order to approve it.  Please contact AMS to arrange this.

TLSFX Pea grenades

TAG R2BS Grenades

TAG Archangles, Reaper, Peckers

 

Yes, the recommendation of legalizing TAGinn projectiles is intended for Lion Claws. They ban TAGinn projectiles, even the dummy and chalk ones, for the concern that they might dent the vehicles.

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Oh, I know, far be it from me to interfere with our resident chicken little telling us the sky is falling.

 

After the TAG thread, I am just waiting for him to disclose in what manner he has a financial stake in defaming NERF...

 

Aswayze, it is unfortunate that you have misunderstood me since the beginning. In all my posts, I have stated that I believe the TAGinn system is safe in terms of kinetics. The only concern I have is that the pyrotechnics projectiles do not have the proper DOT documents to be sold to general public. This piece of information is based on the statement of a licensed pyro technician, who is Milsimlab's owner, as well as reviewing CPSC and BATF regulations. However, judging from the usage of pyro projectiles in events from the past two years, I'd say CPSC and BATF probably don't care about us little fish. And if they do get interested, the only people that might get into troubles are the distributers and retailers, not the event organizers and players. Still, don't quote me on this.

 

In addition, since I am an international student studying in US, I cannot own a business or work outside the campus. I also made all my prevous work open-source:

https://www.facebook.com/pmogarmory/

http://www.instructables.com/id/Airsoft-Rapid-Fire-Grenade-Launcher-Mod/

http://www.instructables.com/id/Airsoft-40mm-Special-Effect-Projectiles/

http://www.instructables.com/id/VFC-SCAR-ProWin-Hop-Up-Mod/

 

 Does it seem like have any conflict of interest?

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It's basic projection.  Not once is the impact resistance listed in the OP or followons.  I'm also curious where you got the FPS for the nerf in the Milsim Labs video - I cannot find it listed anywhere.  Their AT launcher was coming in at around 75FPS, where in the video they were testing a mortar launcher.  

 

Here are my recommendations:

 

1) Look at ALL of the variables when you list calculations.  I can twist math to show all kinds of terrifying things about airsoft, but they are completely irrelevant when you look at the big picture.

 

2) Tell us what your angle is.  Obviously you have a hardon for TAG projectiles - this is why, but don't try to leave us in the dark.

 

3) Learn what BFD is... you list it repeatedly, but never actually use the acronym, which is really, really odd.  I've worked ballistics before and it's one of the more common testing criteria.

 

4) Organize your post.  No one wants to read a paragraph full of equations.  Read a few papers and list your math in the following order:  Explain the basic variables, explain the derived variables, show the equation, list either the variable table or throw them in the equation.

 

5) Look up the impact resistance of automotive glass.  It took me appx 30 seconds.  Range is 29-49 J for concrete and steel.  I'll plot these out in a bit so we can project estimated nerf mass vs energy.

 

6) Don't abandon your thread.  

 

Dave, I was simply quoting Milsimlabs' statement. I'll have to verify with him.

 

Thank you for your suggestions. I'd like to answer your questions one by one:

 

1) You are correct that the ballistic clay indentation estimation are a bit of stetch, but they are projection from Lyon's test results. But 40 J limit is directly from Clemedson and Schneider's work. Are you suggesting that since numbers can be manipulated, let's forget all Airsoft FPS limits, and start shooting each other with 1000 fps BB guns?

 

2) I have nothing against TAGinn system. In fact, I even stated that I think they are safe in terms of kinetics. The only concern I have is that the pyrotechnics projectiles do not have the proper DOT documents to be sold to general public. This piece of information is based on the statement of a licensed pyro technician, who is Milsimlab's owner, as well as reviewing CPSC and BATF regulations. However, judging from the usage of pyro projectiles in events from the past two years, I'd say CPSC and BATF probably don't care about us little fish. And if they do get interested, the only people that might get into troubles are the distributers and retailers, not the event organizers and players. Still, don't quote me on this.

 

3) Thanks. I'll check it out.

 

4) Thanks, that's spot on.

 

5) You mean the "Report on testing to determine impact resistance of vehicle windscreens – overpass screening project"? I'll have to read it in details later. But my main conern is human beings. Paintballers reported that there are instances when players have their masks knocked off and got the wind knocked out of them near 230 fps. I was just using the HUMVEE incidence as clickbait. Speaking of it, there are actually similar incidence at Lion Claws back in 2009 and 2010:

http://www.airsoftcanada.com/showpost.php?p=1218823&postcount=22

http://www.airsoftohio.com/forums/showpost.php?p=242022&postcount=18

 

6) Thanks. For some reasons, the replies didn't show up on the new thread updates, so I didn't see them.

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If players report they had "masks knocked off and wind knocked out of them" then how would a reduction of 8FPS result in a fatality?  I understand the latter is specifically concerning the nerf pocket vortex (~33g), but what was the base model for the previously mentioned report?  If similar, then you need to revise your breakdown.

 

I'll read the rest in a few days.  Very interesting post.  Aren't math and science fun?  

 

It's actually 80 FPS reduction, from 230 to 150 FPS. In terms of kinetic energy, it drops from 78 J (enough to cause fatality) to 40 J (enough to break jaw bones). 

 

REF:

  1. Floroff, S.G."Engineering the Nonlethal Artillery Projectile", Field Artillery, Mar-Apr, 10-12
  2. Clemedson, C., Hellstrom, G., Lindgren, S. “The Relative Tolerance of the Head, Thorax, and Abdomen to Blunt Traumaâ€, Annals New York Academy of Sciences, Vol. 152, 1968.
  3. Schneider, D.C., Nahum, A.M. “Impact Studies of Facial Bones and Skullâ€, Proceddings of the 16th Stapp Car Crash Conference, November 1972

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A great write-up for sure, and important considering how many home-made AT devices we are seeing at AMS events these days. 

 

Aren't teams currently required to pass HW's through admin approval like you would homemade IED/Tripwire mines and such? In the very least there should be some kind of impact test that needs to be passed at chrono. 

 

I don't know about AMS, but at Lion Claws, I didn't see the REFs chronoing grenade or rocket launchers. I didn't see a suitable a chronograph for the job, either.

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We don't chrono them.  This is something that's been going around the campfire for quite some time.  Were just trying to figure out a way to do it. 

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