popsjumper 2 #51 June 14, 2011 Quoteif you need 3 seconds for one full rotation your angle speed of 120 degrees per second. With 4m radius centrifugal acceleration is 1.79g I don't care how you spin it....I just want to know how much 1 gram costs.My reality and yours are quite different. I think we're all Bozos on this bus. Falcon5232, SCS8170, SCSA353, POPS9398, DS239 Quote Share this post Link to post Share on other sites
Skyper 0 #52 June 14, 2011 Human tolerance of g-force Quote Share this post Link to post Share on other sites
devildog 0 #53 June 14, 2011 Quote Quote Quote Did anyone figure it out? The physics behind it is centrifugal force: Fc = m*v^2/r Fc= centrifugal force (can be used to figure Gs) m = mass (kgs) v = velocity (m/s) -- need to convert from RPMs to m/s r = radius (m) Cheat calculator at : http://www.calctool.org/CALC/phys/newtonian/centrifugal Shorter lines say, 1m, 1 RPM 60kg diver Fc = 60 kg * (6.28 m/s)^2 / 1m Fc = 2368 Newtons Gs = 4.02 Longer lines, say 4m, 1 RPM 60kg diver Fc = 60 kg * (25.12 m/s)^2 / 4 m Fc = 9474 Newtons Gs = 16.1The short of it is, take the difference in the lines and multiply by 4 and that will be how many extra Gs the longer set will have, given same RPMs. You have calculated your velocities at 60 RPM (1 rev/second), not 1 RPM as you stated in the example. At 1 RPM the forces are negligible! Yup, sorry! That was suppose to be 1 RPS :)You stop breathing for a few minutes and everyone jumps to conclusions. Quote Share this post Link to post Share on other sites
devildog 0 #54 June 14, 2011 Quote Quote Quote Did anyone figure it out? The physics behind it is centrifugal force: Fc = m*v^2/r Fc= centrifugal force (can be used to figure Gs) m = mass (kgs) v = velocity (m/s) -- need to convert from RPMs to m/s r = radius (m) Cheat calculator at : http://www.calctool.org/CALC/phys/newtonian/centrifugal Shorter lines say, 1m, 1 RPM 60kg diver Fc = 60 kg * (6.28 m/s)^2 / 1m Fc = 2368 Newtons Gs = 4.02 Longer lines, say 4m, 1 RPM 60kg diver Fc = 60 kg * (25.12 m/s)^2 / 4 m Fc = 9474 Newtons Gs = 16.1The short of it is, take the difference in the lines and multiply by 4 and that will be how many extra Gs the longer set will have, given same RPMs. how did you come to: v=6.28 m/s? v=25.12 m/s? r=1m? r=4m? As someone noticed, I said 1 RPM but I calculated 1 RPS. The circumference of the circle would be 2*pi*r, which is 6.28 meters. Then just divide by time (which is 1 second, aka 1 RPS) and you get 6.28 m/s p.s. edit: the radius numbers I picked were just arbitrary and to illustrate what happens when the lines shorten or lengthen.You stop breathing for a few minutes and everyone jumps to conclusions. Quote Share this post Link to post Share on other sites
airtwardo 7 #55 June 14, 2011 Quote Quote if you need 3 seconds for one full rotation your angle speed of 120 degrees per second. With 4m radius centrifugal acceleration is 1.79g I don't care how you spin it....I just want to know how much 1 gram costs. Price often depends on the quantity/quality of the chop... ~ If you choke a Smurf, what color does it turn? ~ Quote Share this post Link to post Share on other sites
ridestrong 1 #56 June 14, 2011 Quote Quote Quote ....the spin could have developed enough force that the jumper couldn't have lifted his arms to reach the cutaway handle. I've heard a few people say that. I have a hard time believing that g-forces can be accelerated high enough under canopy, as to not allow the average jumper to lift (or especially) flex their arms enough to reach their cutaway. Until I see or read proof... I call BS. For those who knew the gentleman please forgive me, but i cant rememebr his name. A guy was jumping one of the ultra small canopies a few years ago (46ft i think), direct deployed off the door, He had line twists, he spun a couple of times, within about 2 or 3 revolutions he had blacked out. Unfortunately he spiralled in and diedThere is a thread on here somewhere about it . I believe the one your thinking about happened in Tennessee... I jumped with the DZO who knew him and told me the story as well. I don't think he ever intended to land that canopy, and the plan was to chop it from the get go... but as you said, he ended up in line twists after deploying from a hop & pop and blacked out nearly right away.*I am not afraid of dying... I am afraid of missing life.* ----Disclaimer: I don't know shit about skydiving.---- Quote Share this post Link to post Share on other sites
