The111

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Everything posted by The111

  1. In simple real life terms... Drive your car down the road, and take a sharp corner, but do it smoothly. You will feel your body leaning against the seatbelt. This is acceleration ("G's"). If you do it smoothly you will feel forces, but they won't cause you to jerk around. Now take a bunch of consecutive left and right turns, but don't do it smoothly. Yank the wheel to the left and right as fast as you can. Your head will get jerked around and you'll give yourself whiplash if you do it hard enough. Or, in the lateral case.... Jerk is what you feel when you are a passenger of one of those shitty drivers who constantly alternates between gas and brake, as your accelerations bounces back and forth around zero. www.WingsuitPhotos.com
  2. You mean da/dt? www.WingsuitPhotos.com
  3. No, it's not. It's all expressed in terms of g-loading. I will admit that from a materials standpoint different materials react differently to sustained g-loading as opposed to sudden g-loadings, but it's all g-loading. Acceleration is expressed in distance per time^2. It can more easily be expressed by a "G factor", the relation of that acceleration to the acceleration caused by earth's gravity. Jerk is expressed in distance per time^3. OR, acceleration per time. I understand your point that when considering mechanical tensile failure of most materials, the absolute load is the most important thing to consider, and not the rate of load. But, you have said twice that jerk and acceleration are the same, and they're not. That's the equivalent of saying speed and acceleration are the same. The reason I'm focusing on this? (besides the fact that I hate to see physics misrepresented) When considering lead dislodgment, jerk plays a much larger role than acceleration. www.WingsuitPhotos.com
  4. Jerk is extremely different than acceleration. Jerk can break your neck ("whiplash"), acceleration cannot. Why are you sighing at me? www.WingsuitPhotos.com
  5. IMO it's more than "G's" (acceleration) you have to worry about, it's jerk (change in acceleration). I don't know a lot about parachute openings, but I'd assume a hard one can have the effect of instantaneously changing you from a 0G load to one of say, 5G's for example. This would wreak a lot more havok on your body than sitting on a roller coaster with a smooth jerk rate that brings you steadily to an acceleration of 5G's. Someone asked if a 20G load wouldn't be just like bouncing? Not really... assuming (arbitraily) a bounce takes .275 second, your average deceleration over that interval would be 640 ft/s^2... about 20G's. You acceleration changed from 0 to 20G's in .275 second... your jerk was 73G/s. On the other hand, if you go on roller coaster than drove in circles (at a steady lateral acceleration rate) until it was going fast enough to accelerate you centripetally at 20G's... you might pass out, but this situation would CERTAINLY not have the same effect that impacting the ground after freefall would. The point of this, to the original poster, is that you can get jerked pretty hard regardless of what the deceleration rate is, but in reality the higher jerk values will occur in the harder openings which also have higher average decelerations. www.WingsuitPhotos.com
  6. Welcome my friend, to the show that never ends... www.WingsuitPhotos.com
  7. How true is this? I have a Vector III on order built for a 170 main. RWS told me their recommendation is only to downsize as far as a 150, but I have heard from others that a 135 would be ok too. That would be awesome and totally extend the life of my rig, but I really don't want to accept hearsay over what the manufacturer deems "ok." www.WingsuitPhotos.com
  8. Hmm, as long as there's already a thread on this... I've been messing around with sit (solo) for 40 jumps or so with no instruction at all, and the worst part is I seem to be getting worse. Two weeks ago I could keep the sit for a whole jump, do flips and 360's and go right back into the sit every time. This weekend I was going all over the place, I probably just wasn't relaxing enough. Anyway, a question about ARMS. I've been jumping with my arms basically shoulder height, and sometimes even back a little (though I'm aware this was to compensate for my chest leaning forward which is bad). I noticed that in most pics I see the arms are pretty high above the head forming a sort of "V" for stability, which makes a lot of sense logically, it's just like an arch on your belly or your legs in HD. I think by flying my arms horizontal I was: 1) Making myself more unstable. 2) Forcing my arm muscles to work harder than they need to, fighting to stay perpendicular to all that wind. 3) Slowing my fallrate quite a bit.... Pro-Track usually has my avg between 140-150, which seems a bit slow, but what do I know? So I can't wait to try it again this weekend and try my new theory about holding my hands higher. This makes sense more after your description about "hanging" from your arms. One last thing... should my hands be in front of the plane my chest creates, or behind it? (Or even with it...) www.WingsuitPhotos.com
  9. My rats. www.WingsuitPhotos.com
  10. Was only $1000 for me... where'd you go? www.WingsuitPhotos.com
  11. Practice your body position in the water. IMO it's impossible to practice a good body position on land... it puts so much stress in your muscles trying to hold your feet and hands above your body while lying on your belly that it gets you thinking you can't relax in that position. Get in a swimming pool, exhale so you can sink, and just pop a good arch and try to focus on all your hangs/legs/feet/arms until you're able to keep them all in good position and stay relaxed. If there's a wind tunnel near you, it may be worth your $. www.WingsuitPhotos.com
  12. Between 1 and 3,999 feet. www.WingsuitPhotos.com
  13. I agree that from a pure statistical point of view (i.e. assuming every deployment/packjob/body-position is the same), time in the sport would not affect the malfunction rate. BUT... I am assuming that people who have been in the sport for 3000 jumps have better packing methods, body position, and are generally safer than people with 100 jumps. www.WingsuitPhotos.com
  14. Heh, not sure I understand... (?) EDIT: Ok, yeh I am aware that 111 is very likely to pop up quite often in binary strings if that was what you meant. www.WingsuitPhotos.com
  15. I dunno, I thought I read some crazy stat that there are like 90k new students every year, but only 34k USPA members. Those stats may be way off, that's what I remember. Bottom line is I don't think a big percentage of jumpers (in the past at least) have continued on to 3k+ jumps... impossible to say what the new jumpers today will do. I could be incredibly wrong. www.WingsuitPhotos.com
  16. What about the fact that not all people with 100 jumps have a probability of continuing on to 3000? :) That makes things more difficult. www.WingsuitPhotos.com
  17. Yeh yeh yeh, I totally agree. :) Which is why I prefaced my post with... It just annoys me, in skydiving AND in other areas of life, when people who aren't qualified to give advice attempt to do it. OBVIOUSLY the jumper has a huge responsibility to himself to make sure he knows 100% how his gear works no matter what anyone tells him... and the manifester is NOT responsible even 1% for the guy's near-incident. I was just saying on an ethical note (disregarding the whole skydiving thing) I hate it when people try to explain something they're not qualified to. And it actually would have been very beneficial for this jumper if he had the same pet peeve as me! Then he wouldn't have accepted such an incomplete explanation... www.WingsuitPhotos.com
  18. Dude, my uncle has a theory about the number 111 and how it pops up in weird places. Hence, my name on this forum. And you just proved my uncle right again. :) www.WingsuitPhotos.com
  19. I understand that as a skydiver you should take all responsibility on yourself and never expect to place the blame for your mistakes on someone else. That said, assuming (heh) your story is worded correctly, I think the manifester here did a pretty shitty thing. If someone asks "where is the rip cord?", then I would guess he hasn't jumped hand deploy, and unless the manifester himself was a non-jumper or low-time jumper too (in which case he should not have attempted to answer the question!) he should have done more than simply pointing at a "string." Hell, regardless of how much experience the manifester has (unless he IS an instructor), if a jumper is showing he doesn't understand fundamental things about the gear he is renting (deployment being the MOST fundamental task in skydiving), he should refer that jumper to an instructor before giving him the rig. My opinion at least... I dunno, something about this story seems lacking to me... a guy who's never jumped hand deploy I wouldn't think would have veyr many jumps at all, and another DZ in another state I would HOPE would do a more thorough check of such a a low time jumper before just handing him a rig. And to the guy's credit, he didn't just assume blindly, he DID ask. Unfortunately he just didn't ask the right person, and he got a shitty answer. I'm sure he learned from that. www.WingsuitPhotos.com
  20. I could be wrong, but I don't think it's possible to sort search results (by date, for example). This would be VERY useful. Thoughts? www.WingsuitPhotos.com
  21. What a load of crap. BMX does not really deserve to be on that list... not saying it's not dangerous, but skydiving should be on a list like that long before BMX. I actually quit BMX because I got hurt a lot, ironically, but I was never afraid of death or paralysis, just frequent pain. I mean, sports like BMX and skateboarding, you never see someone past 30 doing. They always destroy their knees, etc. But you DO see old skydivers. The only other cool sport where you see old people is surfing. Back ON-topic... my mom who is ultra conservative has told me she wants to do a tandem, AFTER defending me when my whole extended family tried to get me to stop skydiving when I started. Had no idea she was cool. Sorry Mel, I know that doesn't help you. Maybe you can at least start them off with a video if you can't get them to a real DZ. Show a whuffo a tunnel video and sometimes they get amazed. www.WingsuitPhotos.com
  22. Hehe, fark rules. And don't forget homestarrunner.com. I'm aways looking for new sites to keep me busy... those last two you posted... are they safe for work? Am I a TradeMarked asshat?! www.WingsuitPhotos.com
  23. I'm a pretty new skydiver with a very big interest in WS flying... I plan on getting into it as soon as I have the required experience and feel ready. I've read a lot on here about modifications to rigs for WS deployments (longer bridles, etc). Question is this: if I only have one rig, and modify it for WS, will it still be as safe to use for normal (freefly, RW, etc) skydiving? My simple mind thinks the answer must be "yes", but is there something I'm overlooking? www.WingsuitPhotos.com
  24. Nice, did you make it yourself? I didn't see it on the page. You should submit it if you did... www.WingsuitPhotos.com