SkydiveMonkey 0 #1 May 25, 2003 Ok, I've been having a debate with my friend about whether a track increases or decreases your vertical speed. I've been trying to tell him a good track will slow down your vertical speed. Anyone care to back me up? Also, he claims jumping from a helicopter takes you to terminal straight away due to the downdraft. ____________________ Say no to subliminal messages Quote Share this post Link to post Share on other sites
mjosparky 4 #2 May 25, 2003 First of all, you should not let your friend drive with out supervision. Does he think if you jump from a big chopper you will get to terminal faster then jumping from a little one? Because the human body has a L/D of less then one, your vertical speed is a little faster in a track. In a track use that extra speed to move vertical. SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
FallingILweenie 0 #3 May 25, 2003 my vertical speed is slower in a track because i usually fly on my head. Quote Share this post Link to post Share on other sites
SkydiveMonkey 0 #4 May 25, 2003 I mean from a "usual" (and I use that term losely ) belly fly. ____________________ Say no to subliminal messages Quote Share this post Link to post Share on other sites
Zenister 0 #5 May 25, 2003 my average vertical speed in a good track is around 90mph (of course i'm tall and relatively light) average belly flight speeds are 120-130mph your friend needs a clue give him a quarter... ____________________________________ Those who fail to learn from the past are simply Doomed. Quote Share this post Link to post Share on other sites
garyharbird 0 #6 May 26, 2003 About a year ago i went on a couple of tracking jumps by myself with just a protrack. I did 1 jump in shorts and tshirt, and 1 in a freefly suit. My results where, Shorts and tshirt 1st half average 106mph, 2nd half average 99mph. Freefly suit 1st half average 98mph 2nd half average 92mph. I'm 5'11 and weigh 165lb So to answer your question yes a flat track does slow your vertical speed. Gary Harbird Quote Share this post Link to post Share on other sites
Kris 0 #7 May 26, 2003 Quite simply, your friend is severly misinformed. Discussion Link 1 Discussion Link 2Sky, Muff Bro, Rodriguez Bro, and Bastion of Purity and Innocence!™ Quote Share this post Link to post Share on other sites
gemini 0 #8 May 26, 2003 In the Last Gasp Tracking contest held yesterday the winner with booties had a vertical speed of 84 mph and 101 seconds of freefall from 13900 ft. The winner without booties had a vertical speed of 82 mph with 88 sec freefall. A good flat track will definitely slow your fall rate. The distance tracked was 2.2 miles. Blue skies, Jim Quote Share this post Link to post Share on other sites
andy2 0 #9 May 27, 2003 [QUOTE]The distance tracked was 2.2 miles[/QUOTE] what alti did they pull at? --------------------------------------------- let my inspiration flow, in token rhyme suggesting rhythm... Quote Share this post Link to post Share on other sites
Skylark 0 #10 May 27, 2003 QuoteIn the Last Gasp Tracking contest held yesterday the winner with booties had a vertical speed of 84 mph and 101 seconds of freefall from 13900 ft. The winner without booties had a vertical speed of 82 mph with 88 sec freefall. A good flat track will definitely slow your fall rate. The distance tracked was 2.2 miles. Hang on, if they both fell at the same vertical speed, how on earth did one person get an extra 13 seconds of freefall? Isn't that over a thousand feet? "Into the dangerous world I leapt..." William Blake, Songs of Experience Quote Share this post Link to post Share on other sites
chuteless 1 #11 May 27, 2003 On October 16 1971, I installed a directional pitot tube on the topside of my helmet, so the front of the tube would penetrate the air clear of any turbulence caused by my head or body. The tube ran through a hose inside a metal flex ripcord housing so it couldnt be crushed by the harness or my front mount reserve. Across the top of my reserve, was a 3/8" thick strap of aluminum about 24 inches long. On one end, was mounted a stop watch, a sensitive altimeter, and an air spedd indicator. On the other end of the aluminum was a 16mm GSAP camera with a 50 magazine of film. I also had a jet pilot's helmet on, and in the oxygen mask, a microphone plugged into a small tape recorder., the mask preventing air flow from dirrupting the comments made during the jump. I left the Cessna l80 at 8200 ft AGL, and recorded " Leaving aircraft now" and in the film you can see me start the stopwatch. I went into the basic stable spread and quickly was recording on film, a speed of 150 MPH. I then said " High Speed Dive Now" and went head first straight down, with my arms alongside my body. The speed can be seen climbing quickly to 225 MPH. After some time, I said "stable position" and flared out, again at a speed of 150 MPH. Later I wrote a lengthy article and covered all aspects of the jump, drew a graph showing altitude, speed, and time. I sent it to PARACHUTIST (USPA). About a month or so later, I phones USPA and asked them if they got it, and they acknowledged they did, but they said they had lost it. It was an interesting experiment, and I think with enough altitude, I could break 300 MPH. I would like to do it again from about 30,000 or so. Who knows...maybe one of these days. I still have positive photos taken from strips of the negative roll of film, showing the speed etc. It was a unique jump fo sure. Bill Cole D 41 Canada Quote Share this post Link to post Share on other sites
Zenister 0 #12 May 27, 2003 QuoteQuoteIn the Last Gasp Tracking contest held yesterday the winner with booties had a vertical speed of 84 mph and 101 seconds of freefall from 13900 ft. The winner without booties had a vertical speed of 82 mph with 88 sec freefall. A good flat track will definitely slow your fall rate. The distance tracked was 2.2 miles. Hang on, if they both fell at the same vertical speed, how on earth did one person get an extra 13 seconds of freefall? Isn't that over a thousand feet? those are probably average speeds from a protrack. its unlikely they both kept their average speed up the entire time.. i imagine the overall winner had a better low end speed and/or a more consistant slow fall rate...____________________________________ Those who fail to learn from the past are simply Doomed. Quote Share this post Link to post Share on other sites
andy2 0 #13 May 27, 2003 [QUOTE]It was a unique jump fo sure[/QUOTE] Awesome man, if you find the info post it for us to see since USPA were bitches and lost it. --------------------------------------------- let my inspiration flow, in token rhyme suggesting rhythm... Quote Share this post Link to post Share on other sites
SkydiveMonkey 0 #14 May 27, 2003 Doesn't make a difference. If the average is slower for the whole dive, he should have more freefall time, whether his speed is erratic or not.____________________ Say no to subliminal messages Quote Share this post Link to post Share on other sites
Zenister 0 #15 May 27, 2003 not nessesarily if the average is the result of two extremes he will have lost more altitude during the high speeds than someone who's average speed is the result of less overall variation____________________________________ Those who fail to learn from the past are simply Doomed. Quote Share this post Link to post Share on other sites
SkydiveMonkey 0 #16 May 27, 2003 but if he speed up at times, he must have had some very slow moments as well to bring the average back down____________________ Say no to subliminal messages Quote Share this post Link to post Share on other sites
kallend 2,027 #17 May 27, 2003 Quotebut if he speed up at times, he must have had some very slow moments as well to bring the average back down It all depends how the "average" is computed. I don't have my manual here right now but some parts of the skydive are omitted from the calculations. I'm very skeptical of Protrack speeds anyway - there seems to be a lot of unaccounted-for variation between jumpers on the same formation, and even between two instruments on the same skydiver. Maybe Craig Poxon has more info. I believe the times to be a more accurate measure than the speeds, although even the times incorporate the snivel.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
andy2 0 #18 May 27, 2003 I've heard before that pro-track and other like gear can oftentimes be trapped in a temporary burble, say an arm, leg, etc etc, that would effect the speeds, etc. Is this true? --------------------------------------------- let my inspiration flow, in token rhyme suggesting rhythm... Quote Share this post Link to post Share on other sites
FreeDiver 0 #19 May 27, 2003 euhh newbie question since I'm still at level 4 and tracking has yet to be learned What's kind of horizontal speeds can you archieve while tracking ??? thanks Quote Share this post Link to post Share on other sites
SkydiveMonkey 0 #20 May 27, 2003 It cuts of the last 7 seconds from the calculations, and the first 12 seconds (?)____________________ Say no to subliminal messages Quote Share this post Link to post Share on other sites
poohbeer 0 #21 May 27, 2003 QuoteWhat's kind of horizontal speeds can you archieve while tracking ??? From a topic in S&T that's 'running' now: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=95649#95649 ------- SIGNATURE BELOW ------- Complete newbie at skydiving, so be critical about what I say!! "The only thing necessary for the triumph of evil is for good men to do nothing." Quote Share this post Link to post Share on other sites
Zenister 0 #22 May 27, 2003 Quotebut if he speed up at times, he must have had some very slow moments as well to bring the average back down true and as has been pointed out there are burble and other factors to consider in the protrack numbers. i've gotten spikes as low as 53 mph on my protrack and i doubt my track is that good..but one spike in the right place could change the average.. i have a bit more faith in the graphs than i do in the 1/3 dive numbers you get off the display..____________________________________ Those who fail to learn from the past are simply Doomed. Quote Share this post Link to post Share on other sites
freakydiver 0 #23 May 27, 2003 Are you serious? You think vertical speed is faster in a track??? Where did you learn to track???? Didn't they show you how to dearch and get the shoulder curl working to slow your fall rate - thus the "flat track" terminology??? Remind me not to get on a bigway with you. -- (N.DG) "If all else fails – at least try and look under control." -- Quote Share this post Link to post Share on other sites
dreamsville 0 #24 May 27, 2003 I have seen this speed variation anomaly recently when Protracking sit-fly to headdown transitions. Based upon body position, horizon, and wind-flow feel, with or without someone present, you have some indications of being in a decent sit or headdown (no arching, please). During the first transition from sit to head-down, the PT graph recorded changes from the sit 150-160's range, BACK DOWN TO 100 briefly, and then back up to 160-170s, all this in a moment or two. Especially with transition times typical today, I don't think we could achieve such a true fast deceleration and acceleration in such a short time. I can only guess that burbles/changes in airflow in the helmet area of the PT pollute the data. It is best to use longer intervals on a PT graph to get an idea of free-fall speed, since big, short, up down spikes are suspect. I think the reccommendation is for PT to be at one end of the body (ankle strap or helmet) or the other. PT located in the midsection of your body may distort the readings further. Edited to add: ankle strap experiment may sound strange, since of course you can't hear the sound. I had a Skytronic Pro audible in my helmet until it died and had to return to the factory. As far as whether one location was better than the other for readings, I'm not sure. I think I'll keep both in the helmet when the ST comes back (taking forever). | I don't drink during the day, so I don't know what it is about this airline. I keep falling out the door of the plane. Harry, FB #4143 Quote Share this post Link to post Share on other sites
Zenister 0 #25 May 27, 2003 the problem with having it on your ankle is you get some REALLY wild changes when transitioning from head down to stand..i've got one spike (from the day i wore it on my leg) of 400 something mph!!____________________________________ Those who fail to learn from the past are simply Doomed. Quote Share this post Link to post Share on other sites
