Nerf Rocket Cracked a HUMVEE Window!

[PMO Gordo]

 

NERF ROCKETS CAN BE LETHAL!! This video from Amped Airsoft showed that they still can crack a BULLETPROOF 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 Munitions”, 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 Studies”, 2008
3. Clemedson, C., Hellstrom, G., Lindgren, S. “The Relative Tolerance of the Head, Thorax, and Abdomen to Blunt Trauma”, Annals New York Academy of Sciences, Vol. 152, 1968.
4. Schneider, D.C., Nahum, A.M. “Impact Studies of Facial Bones and Skull”, Proceddings of the 16^th Stapp Car Crash Conference, November 1972

 

 

 

 

 

[Got Wood?]

To be honest this assumes that the glass on it was in fact bullet proof. Looking at the way it cracked, I'm willing to bet it's not.

 

They probably saved a tonne of money on the vehicle by getting it without ballistic glass, and just regular Windows.

 

Also, I don't think that nerf was travelling at 230, definitely more like 350

[ED-SKaR]

To be honest this assumes that the glass on it was in fact bullet proof. Looking at the way it cracked, I'm willing to bet it's not.

 

They probably saved a tonne of money on the vehicle by getting it without ballistic glass, and just regular Windows.

 

Also, I don't think that nerf was travelling at 230, definitely more like 350

I'm sure he hadn't put in a metal weight to make it fly further and more accurately either.

[Leshy]

That's not bullet proof glass, tint colouring is wrong, impact crack pattern absorption is wrong for bluntforce impact.

My guess is that it's probably Ill fitted or had a minor weakness either manufacturing or a small chip.

[jal3]

What's the air drag on a nerf rocket? Probably quite a lot.

 

A paintball comes out with 12J and delivers the energy over 1 cm2.

 

Looks like a total kneejerk reaction to a situation with unknown factors. Do some proper testing instead.

[Lone_Bullet]

Topic like this could end in Nerf being out-lawed. Good job.

How about we don't panic and don't conclude anything until nerf rockets around the world start killing people?

[tquilha]

My 5 nephews are quite addicted to NERF and I'm basically a large walking target whenever I get to their home. There is NO way a normal NERF rocket would crack any kind of car glass, much less ballistic glass.

Now, I don't know what the rocket was shot out of (I guess NOT a NERF launcher...) and if there were any mods done to it. But regular NERF does not have enough power yo knock your basic small vase down.

[DrAlexanderTobacco]

Nerf killed my entire family.

[hitmanNo2]

Guys, this is a Hummer we're talking about.  Not exactly know as being a safe vehicle ha ha.

 

But seriously though, the glass doesn't look very thick, like regular windscreen glass.  It can't be properly armoured.

[PMO Gordo]

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.

 

To be honest this assumes that the glass on it was in fact bullet proof. Looking at the way it cracked, I'm willing to bet it's not.

They probably saved a tonne of money on the vehicle by getting it without ballistic glass, and just regular Windows.

Also, I don't think that nerf was travelling at 230, definitely more like 350

 

 

That's not bullet proof glass, tint colouring is wrong, impact crack pattern absorption is wrong for bluntforce impact.
My guess is that it's probably Ill fitted or had a minor weakness either manufacturing or a small chip.

 

 

My 5 nephews are quite addicted to NERF and I'm basically a large walking target whenever I get to their home. There is NO way a normal NERF rocket would crack any kind of car glass, much less ballistic glass.

Now, I don't know what the rocket was shot out of (I guess NOT a NERF launcher...) and if there were any mods done to it. But regular NERF does not have enough power yo knock your basic small vase down.

[hitmanNo2]

I don't know.  Windscreens are surprisingly fragile.  I've seen them crack whilst under slight pressure from fitting wipers.  Numerous reports of them braking from football impacts too.

[PMO Gordo]

What's the air drag on a nerf rocket? Probably quite a lot.

 

A paintball comes out with 12J and delivers the energy over 1 cm2.

 

Looks like a total kneejerk reaction to a situation with unknown factors. Do some proper testing instead.

 

That 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 damage”. 122+joules is listed as “Severe Damage” i.e. “massive skull fractures, rupture of the heart and kidney, and fragmentation of the liver”

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 “dangerous”

@ 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 https://www.youtube.com/watch?v=Wl_vmicK31Q

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

[Roland1014]

Weed out the weak.

 

 

Only the strong survive.

[Roland1014]

This is why you don't use windex on HUMVEE windshields

[Roland1014]

You can wear your bubblewrap suit to bblarp in, but let the big boys play the way they want.

[Lone_Bullet]

Roland, had a drink, mate? ^^

[Danke]

Link in the original post is DOA. No movie of a shot to a windshield that I can see. What time is it at?

[hitmanNo2]

Definitely still working.  At around 16 second mark.

[Got Wood?]

Nerf killed my entire family.

Nerf killed my father. And raped my mother!

[Danke]

Oh at the very start with no context at all. Lovely.

 

This is bullet resistant glass. Note use of safety goggles by shooter.

 

https://youtu.be/3ZzoB6xBWOI

[Roland1014]

Roland, had a drink, mate? ^^

I don't drink

[Roland1014]

And I'm mildy rustled by the fact that Gordo here is so quick to claim that a

F O A M *fruitcage* football cracked a bulletproof windshield that isn't even available to civilians when they purchase demilitarized humvees.

 

Hence the -> de militarized <- part.

 

The evike hummer had its windshield cracked by a Nerf as well. Its not really a big deal. Hot air can crack windows too, and I don't see hair dryers requiring licenses to own.

 

Hell, some dude can shatter wine glasses with his voice!

[PMO Gordo]

A less inflammatory version of the post:

 

Video:

A Nerf rocket cracked Amped Airsoft's HUMVEE windshield at Irene 2015. Although the windshield was not the bulletproof model, the impact still seemed substantial and could have caused serious injury if hitting a player. Therefore, an investigation of the rules and their enforcement regarding use of large caliber projectiles in both Airsoft and paintball games is warranted. The aims of this essay 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.

From what I can gather from the Web, 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. 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.

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 and Paladin), the maximal velocity should be less than 180 fps. But for the sake of simplicity and additional protection, 150 fps should be the maximal velocity for all projectiles.
2. Large caliber projectiles for Airsoft or paintball games should also have maximal energy density of less than 3.7 J/cm^2. Nerf rockets and TAGinn projectiles should already meet this criteria after tuning down to 150 fps.
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 real 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 does not have as much effect on safety as previously thought. TAGinn dummy projectiles (Pecker) should be allowed in games, and if sites allow, the chalk ones (Paladin) as well.

REF:
 

1.  Lyon, D.H., Bir, C.A., Dubay, D. “Inury Evaluation Techniques for Non Lethal, Kinetic Energy Munitions”, 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 Studies”, 2008
3.  Clemedson, C., Hellstrom, G., Lindgren, S. “The Relative Tolerance of the Head, Thorax, and Abdomen to Blunt Trauma”, Annals New York Academy of Sciences, Vol. 152, 1968.
4. Schneider, D.C., Nahum, A.M. “Impact Studies of Facial Bones and Skull”, Proceddings of the 16th Stapp Car Crash Conference, November 1972

[Danke]

What were the rules for projectiles at said game?

[Dentonboy]

Reminds me of a scene in the superlative Arrested Development when George Bluth is on the lam and has to chose between a HUMVEE and a replica Pope Mobile for the safest getaway. He choses the Pope Mobile...