zhark 0 #1 January 4, 2005 Hi Was wondering if anyone had a "magic formula" to figure out how much lead equates to how much extra speed in freefall? There are a lot of factors which influence this, but was hoping for a kind of rough guide. Any ideas would be appreciated. Blue ones, Jacques Quote Share this post Link to post Share on other sites
D22369 0 #2 January 4, 2005 I havent ever seen a gage on how much lead produces what speed, but ten pounds should speed you up and make freefall with the fat bastards a bit easyer.... I was recovering from fracturing two vertebre in my back a few years ago, ten pounds made it easyer to fly with a 40 way, 20lbs made it a cake walk, .... except for the walking part... and damnit you really look like you need to do a few situps on video.... I was always told if you need more than ten, you need a slicker jumpsuit, or arch harder, just experiment a bit, borrow a friends vest and try it, I have known several jumpers that only had five pounds in thier vest and they swore by it.. RoyThey say I suffer from insanity.... But I actually enjoy it. Quote Share this post Link to post Share on other sites
zhark 0 #3 January 4, 2005 LOL - I'm afriad that *I'm* the fat bastard . I'm trying to figure out how much lead people need to jump with me! Too much Christmas cake.... Our 4-way team has this more or less sussed at a steady 124mph (matching my fallrate), but it's always a guessing game with students and new jumpers. I guess the more weight the better, since I can always go faster??! Docked a 5-way at 107mph this weekend, so I guess can CAN go slow, but *damn* that was cupping just about every part of my body...even my mouth was open!!! Quote Share this post Link to post Share on other sites
darkwing 4 #4 January 4, 2005 The physicist part of me says there is no magic formula. Too many variables associated in complex ways. Try until you get it right. -- Jeff My Skydiving History Quote Share this post Link to post Share on other sites
freakbrother 0 #5 January 4, 2005 QuoteThe physicist part of me says there is no magic formula. Too many variables associated in complex ways. Try until you get it right. The physicist in me says the exact same thing, but the empiricist says I (me) get about 2mph extra for each 3 pounds of lead, when starting at 110mph, for amounts between 0 and 15 pounds. Would obviously be different for other body shapes and sizes. Linear enough over that limited range.. . www.freak-brother.com Quote Share this post Link to post Share on other sites
zhark 0 #6 January 5, 2005 Quote The physicist part of me says there is no magic formula. Too many variables associated in complex ways. Try until you get it right. The mathematician in me says there is an equation for everything! QuoteThe physicist in me says the exact same thing, but the empiricist says I (me) get about 2mph extra for each 3 pounds of lead, when starting at 110mph, for amounts between 0 and 15 pounds. Would obviously be different for other body shapes and sizes. Linear enough over that limited range. Based on my girlfriend's protrack, I had a look at last nite, I got the following stats: 143lbs (exit weight w/o lead) = 116mph ave 153lbs (with lead) = 123mph ave 10lbs = 7mph faster OR 0.7mph / lbs if you like So 3lbs = 2.1 mph faster. Hmmmm....seems you're on to something there... Anyone else have more data that we can work with? I guess the resultant equation would be extremely complex, but perhaps 2mph/3lbs is a good guide to start with....Well, I'll try it and see how it works out.... Thanks for all the help guys... Quote Share this post Link to post Share on other sites
darkwing 4 #7 January 5, 2005 QuoteBased on my girlfriend's protrack, I had a look at last nite, I got the following stats: 143lbs (exit weight w/o lead) = 116mph ave 153lbs (with lead) = 123mph ave I'm not arguing with the empirical results, but I have larger variations than that in one day without any weight changes. Having said that, starting with the assumption that 3 lbs give you 2 mph probably is a good starting point. -- Jeff My Skydiving History Quote Share this post Link to post Share on other sites
mjosparky 3 #8 January 5, 2005 You are about 210 out the door. This should put you at a good fall rate for medium sized formations. Work on increasing your ff speed range through body position and let the other guy worry about what he/she needs. SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
freakbrother 0 #9 January 5, 2005 QuoteQuoteBased on my girlfriend's protrack, I had a look at last nite, I got the following stats: 143lbs (exit weight w/o lead) = 116mph ave 153lbs (with lead) = 123mph ave I'm not arguing with the empirical results, but I have larger variations than that in one day without any weight changes. Having said that, starting with the assumption that 3 lbs give you 2 mph probably is a good starting point. Come to that, I can go from 95 to 135 and back again on my belly in a single skydive. However, the 2mph/3lbs seems to work for average speeds in my comfort zone. I'm sure a tiny person would see more of an effect per lb added.. . www.freak-brother.com Quote Share this post Link to post Share on other sites
headoverheels 291 #10 January 5, 2005 First cut, your speed will vary as the square root of exit weight, if nothing else changes. Depends on how the lead is placed. Lead on the belly may actually streamline, resulting in a bit more increase in fall rate. e.g., if one has an exit weight of 170, and adds 10#, the fall rate would increase in the range of 2.9%. Maintaining the same body position, you would fall about 5 feet per second faster. Quote Share this post Link to post Share on other sites
