Hard Hats in HPR

Discussion in 'High Power Rocketry (HPR)' started by lowga, Nov 18, 2018.

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  1. Nov 18, 2018 #1

    lowga

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    BAR, only returned to rocketry about two years ago--and that was my first foray into HPR. Old enough (and hopefully wise enough) to be very serious about safety. Fortunate to be in a section that feels the same way.

    I'm curious if the NAR or TRA has ever considered adding a requirement for HPR flyers to wear hard hats while on a launch site? It seems like a simple, and inexpensive way to greatly increase safety at a low cost.

    Hard hats are no fun to wear--especially outdoors in the summer time. But if you visit a construction site where there is the slightest possible of someone dropping a tool, brick, or other objects from a great height, you'll be required to wear one while on site.

    Pardon the newbie question.
     
  2. Nov 18, 2018 #2

    blackjack2564

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    Rocket of any size coming in ballistic would break your neck, even if the hard hat saved a puncture. Like getting hit in the top of head with a 20lb sledge at 80mph.

    The small amount of protection hardly warrants the effort. [IMO] I wore hard hats for years on big commercial jobs. A tool falling from a couple stories up is far different than a several lb rocket coming in at even small terminal velocity 120mph..thats the bottom of the scale...several hundred mph if from high altitude.
     
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  3. Nov 18, 2018 #3

    MClark

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    There are flyers who wear hard hats at launches. They serve a very good function, from a long ways away you know the person is not right and you will not make the mistake of speaking to them.

    M
     
  4. Nov 18, 2018 #4

    Steve Shannon

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    Never feel bad asking a question about improving safety.
    As far as hard hats, I would rather see launch directors work on range management techniques that result in rockets falling down range so that hard hats are not needed.
    In reality I’ve seen pictures showing rocket piercing vehicle roofs. A hard hat wouldn’t protect you.
     
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  5. Nov 18, 2018 #5

    boatgeek

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    As others said, a hard hat isn't going to help with a ballistic rocket. For anything with a chute out or even just separated and tumbling, getting out of the way is going to be better than a hard hat.

    However, I do think there is one application where it would be helpful--where the rocket is being elevated on a large and heavy pad like you sometimes see for very large rockets or someone doing a high altitude shot. If raising and lowering the pad (including lowering in case of a failure) is done with anyone in the fall radius of any pad parts, a hard hat would be a good idea. Basically, if you need a machine to raise it, it would probably hurt if it fell and hit you on the head.
     
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  6. Nov 18, 2018 #6

    mccordmw

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    And many of our HPR nosecones also have aluminum tips.
     
  7. Nov 18, 2018 #7

    DAllen

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    As someone who wears a hard hat about 50% of the time for work I can say this is a terrible idea. Hart hats have brims. Those brims are needed to help protect the face:

    https://www.oshasafetymanagement.com/ppe-focus/hard-hats/

    The big problem with brims is the increased difficulty in looking up. I think impairing this ability to look up negates any and all benefits to wearing a hard hat at a launch where if you are looking up it is more likely you are going to see hazards such as ballistic rockets, debris from shreds or even a rocket under chute and thus get out of the way.

    -Dave
     
  8. Nov 18, 2018 #8

    MattJL

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    I can vouch for this - we had a booster lawn-dart into the field hard enough that the fins sliced through the (fiberglass) body tube a good 6-7". Fortunately, all it took out was a couple carrots. I don't think a hard hat would have done too much.
     
  9. Nov 18, 2018 #9

    cbrarick

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    Hard Hats won't help you if something is coming in at your head. Moving out of the way will.
    I agree that it's hard to look up with them. Making avoiding harder.
    I wonder how many people flying HPR have been hit in the head.
    I bet ejection charges and igniters are much bigger risks.

    Plus, it would be a compliance nightmare. Who would be the hard-hat police? Would they be required for just HPR flyers, or would you hand them out to spectators as well? Would LPR flyers at a launch with HPR be required to wear them? Would clubs be required to supply them to spectators? Who would buy, store and inspect them? Where would they be stored? If a club runs out of hard hats and more spectators show up and it's public lands, would the club have to cease operations for the day?

    ANY new regulation should always weigh out the risks & benefits, as well as how you would make it work and enforce it as well as burden to those effected.

    Example: We all know drunk driving kills. Ignition interlocks prevent drunk driving. are you going to voluntarily sign up for one? Probably not. They're expensive and a PIA.
     
  10. Nov 18, 2018 #10

    JimJarvis50

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    A few years back, I was helping a friend load a rocket. 6" rocket if I recall, probably an M motor. My friend has this trademark hat, sort of sombrero, so some of you might know who I'm talking about. Anyway, we loaded it on the pad, and we were concerned about the stand-off, as the pad wasn't quite designed for the size of the rocket. We got it loaded and then he turned on the electronics. As he was checking continuity, sure enough the rocket fell off the stand-off with a good thud. We were looking at it, trying to figure out what to do next, and roughly 6 seconds later, here comes the upper air frame. It hit the brim of his sombrero on the way down. Now, he wears a hardhat.

    Jim
     
  11. Nov 18, 2018 #11

    mccordmw

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  12. Nov 18, 2018 #12

    grouch

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    Maybe we should start wearing the asian bird flu mask as well?
     
  13. Nov 18, 2018 #13

    Nathan

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    I was once helping someone prep a very large rocket at the away cell. When he armed the electronics the deployment charge fired. I just heard a boom, then the big heavy nose cone hit the ground a few feet from where I was standing. No one was hurt but if it had landed on my head, I would have wished I had a hard hat.
     
  14. Nov 18, 2018 #14

    Banzai88

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    Last edited: Nov 18, 2018
  15. Nov 18, 2018 #15

    cwbullet

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    Ballistic: Unless it is an estes or mid power, I agree with will not save you.

    For rockets falling off the pad or falling rails might, it might help.
     
  16. Nov 18, 2018 #16

    lowga

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    As my high-school teacher used to say, "Physics don't give a damn." The forces involve would certainly make a hard hat nearly useless in the majority of circumstances. Should have thought of that myself.

    Thanks for setting me straight.
     
  17. Nov 18, 2018 #17

    cwbullet

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    It all about momentum and kinetic energy.
     
  18. Nov 19, 2018 #18

    les

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    My one experience was actually a 2 stage LPR. Barely got off the rod, went horizontal and ignited its second stage which shot directly in spectators. A guy wearing a cowboy hat got hit in the head. It sliced through the hat and gave him a laceration, but fortunately nothing major.

    And I can't readily locate it, but there was the picture of the incident with AMW where again, an LPR, came in ballistic and punched a hole through their trailer roof.

    If an HPR come in ballistic, the hard hat merely provides a target......
     
  19. Nov 19, 2018 #19

    Nathan

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    And fewer people would get hurt in car accidents if everyone always wore helmets and Nomex suits and used 5 point harnesses when driving. There is always a trade off on how much safety you want vs how much inconvenience/cost/discomfort you're willing to accept.
     
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  20. Nov 19, 2018 #20

    jlabrasca

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    Interesting point. The only time I've been struck by a falling object at a launch, was an 18 mm Estes motor. It was stunningly painful, but didn't penetrate.

    Not for nothing, but for a rocket falling ballistically -- a single body -- momentum and KE at the moment of impact are simply related. Its really enough to say "kinetic energy".

    momentum_KE.png
    It's not a big deal, and seriously I am not criticizing, but for a physicist its a little like hearing somebody say "for all intensive purposes" or "it begs the question" for "it raises a question". The urge to explain is irresistible. I am, in fact, a pedantic prig.
     
  21. Nov 19, 2018 #21

    cwbullet

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    I saw an Estes rocket cause a nasty abdominal laceration with bruising. I am sure it hit right, it could penetrate the abdominal wall.

    I am not a physicist and I am a little far from that part of my education. I will use the term kinetic energy.

    So momentum keeps it moving and creates penetration or is that kinetic energy also?
     
  22. Nov 19, 2018 #22

    DAllen

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    Confession is good for the soul lol
     
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  23. Nov 19, 2018 #23

    cwbullet

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    That is funny no mater who you are.
     
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  24. Nov 19, 2018 #24

    jlabrasca

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    That's a tricky one. How deep do you want to dive? The rocket falls because it has weight. So you might say that it is the force gravity that "keeps it moving" while it is falling.

    During the collision with a hard hat, we'd invoke the conservation of momentum to describe the forces that act between the rocket and the hat -- but physical laws are not explanations. Newton's first law only describes the state of motion; in the absence of a net external (to the rocket) force, the rocket's momentum will not change. I would not say that the momentum of the rocket "keeps it moving". Rather I would say that the forces exerted by the body with which it collides change the momentum of the rocket.

    Newton's 3rd law, which is properly an expression of the conservation of energy, then allows us to discuss the force exerted by the falling rocket upon the hard hat (and the head inside).

    I do wonder about a falling high power motor. I've seen fliers friction mount quite large motors. It occurred to me at the time that a 38mm casing would be a hard-to-see, heavy, and rigid body coming down in the case of a retention failure.

    Oh, and it is well-known that physicists are soulless, tedious, and unsympathetic. I, assume. At least that what my evaluations tend to indicate.
     
  25. Nov 19, 2018 #25

    cwbullet

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    Today, I understand you a lot more. Thanks.
     
  26. Nov 19, 2018 #26

    grouch

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    I promise you non of this would matter to you if you got struck in the head hard enough.
     
  27. Nov 19, 2018 #27

    Wallace

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    Not saying they don't have their place. But after 25+ years of having to wear/enforce the wearing of said the best I've seen is heat exhaustion and or broken noses wearing the requisite safety glasses. Anything that limits peripheral vision and adds 2 plus inches to head height is not good.Not one single time have I seen a hard hat help in any way. This is from personal experience, certainly not all encompassing.
     
  28. Nov 19, 2018 #28

    Wallace

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    And yes, it was my personal responsibility to attend any and all injured parties.
     
  29. Nov 19, 2018 #29

    Bat-mite

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    Biggest safety issue I ever see at launches is spectators not spectating. There are always people who are there just to hang out and socialize that don't pay attention to what is going on. Ii have seen the LCO calling "Heads up! Heads up!" and a rocket come in ballistic near a group of people who had no clue what was happening around them. Finding a way to convince people to pay attention would be the biggest safety improvement I can think of.
     
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  30. Nov 19, 2018 #30

    Steve Shannon

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    Yes, exactly.
    At a small launch like the local ones we have, we typically stop and explain the meaning of “heads up”. Unfortunately, “heads up” is greatly overused to mean everything from “on your feet while we launch this rocket for its first time”, to an Estes model falling out on the range with a fused parawad.
     

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