JohnMitchell 14 #76 September 4, 2012 Quote Sundevil, Thanks "flat" relative to the group make much more sense. I was thinking more relative to the earth or 3D flight. I'm old friends with Sundevil but I disagree with him on this point. What do you call your tracking if you go ABOVE the group? Superflat? It's about your most efficient glide angle, not your relativity to anyone else. Quote John Mitchell, I have been logging GPS data with a FlySight and even with my homemade tracking pants I have yet to get 1:1. I got 0.92 on one jump. Here, let me quote myself "Some of the GPS data here shows people approaching that number. Okay, I'll buy that number. " And no offense, but some of the people with thousands of jumps might be able to dial it in more than someone in the double digits. No offense. I need to get me one of those GPS trackers. Quote It should not be a surprise but interia appears to be a factor. I am talking beyond normal separation type tracking, but max performance type tracks. Even if you can track hard and fast, getting that mass moving (your butt) horizontally takes time and energy. I agree about inertia. It takes a while to accelerate any thing with mass. I'd be very interested to see what my acceleration graph looked like. Quote When I get my skills up a bit more, I want to work on short tracking for separation and see what adding a little time to separation tracking will do. Everyone knows you will go further (of course). But I want to see if 6 seconds would make a small or a large difference over 4 seconds. Well, it should take you at least 50% farther away, right? Remember, you only need enough separation. You don't want to track so far up or down the jumprun line that you get in the other groups' airspace. It's great to see you working on your tracking skills. I'm afraid most jumpers don't track as well as they could. Too bad, because it's a huge survival skill. Quote Share this post Link to post Share on other sites
kallend 1,623 #77 September 4, 2012 Quote Quote I think the "flat" refers to not falling faster than you would fall normally in freefall, so that if you were to stay in a formation, a flat track would have someone move horizontally relative to you. It is actually possible for it to be slower than normal. My definition of a flat track is one that gets the most horizontal travel for a given amount of altitude, which is always the goal when breaking off. This goal is equal to having the best glide ratio, or lift-to-drag ratio. Every flying object has a maximum L/D ratio it can achieve. This is achieved at a certain angle of attack for that flying object, whatever it may be. Someone said that for the human body, they felt is was about a 45 degree angle of attack. I don't know for sure but this sounds close to correct, or at least very plausible. For years I've heard glide ratios of 1-to-1 quoted for efficient tracking. In other words, for every foot you drop you go one foot forward. Some of the GPS data here shows people approaching that number. Okay, I'll buy that number. So, if the human body's best angle of attack is about 45 degrees, and the best glide ratio of a good tracker is 1-to-1, or 45 degrees, then an efficient tracker in full on Ricky Bobby mode should have their body almost level with the horizon. That's 45 degrees angle of attack above their 45 degree glide ratio. Cool.A friend's video caught me tracking the other day. I noticed my body was tilted only 10-15 degrees down from the horizon behind me. I think I might be doing okay. That would be the case for a steady state track, but what gets you away from a formation involves a transition from falling vertically. In my experience it takes several seconds to get to a steady state track. Ass-uming the value of 45 degrees angle of attack for max lift, the first several seconds of track off need to be at a steeper attitude angle than in the steady state.... 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
5.samadhi 0 #78 September 4, 2012 http://www.youtube.com/watch?v=_VW5qzBQQlI I think those guys are doing a pretty good functional track away from a 4-way. Start video about 55 seconds to see their breakoff. nobody dives away everybody stays on level pretty much. Quote Share this post Link to post Share on other sites
scottd818 0 #79 September 4, 2012 Quote http://www.youtube.com/watch?v=_VW5qzBQQlI I think those guys are doing a pretty good functional track away from a 4-way. Start video about 55 seconds to see their breakoff. nobody dives away everybody stays on level pretty much. CLICKY Quote Share this post Link to post Share on other sites
rehmwa 2 #80 September 4, 2012 . . "meat plows" ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites
dthames 0 #81 September 4, 2012 Quote -------------------------------------------------------------------------------- In Reply To -------------------------------------------------------------------------------- It should not be a surprise but interia appears to be a factor. I am talking beyond normal separation type tracking, but max performance type tracks. Even if you can track hard and fast, getting that mass moving (your butt) horizontally takes time and energy. -------------------------------------------------------------------------------- I agree about inertia. It takes a while to accelerate any thing with mass. I'd be very interested to see what my acceleration graph looked like. -------------------------------------------------------------------------------- In Reply To -------------------------------------------------------------------------------- When I get my skills up a bit more, I want to work on short tracking for separation and see what adding a little time to separation tracking will do. Everyone knows you will go further (of course). But I want to see if 6 seconds would make a small or a large difference over 4 seconds. -------------------------------------------------------------------------------- Well, it should take you at least 50% farther away, right? Remember, you only need enough separation. You don't want to track so far up or down the jumprun line that you get in the other groups' airspace. I am not looking to track a lot further on an RW jump but I do want to know if someone says, break at 4500 and pull at 3500, I wan to know if that will allow me to track X number of feet. If I know that I will come up way short on the tracking distance, then that is valuable information. Take a look at the attached file. I was ready to track and flying above a friend with a camera. I had my legs on my butt trying to hold position with him. It could be the wind or my flying but I was going about 10 MPH (horz velocity) when I started the track. It took about 3 seconds to get up to 20 MPH. Whatever distance I traveled in those 3 seconds, it might be doubled by holding the track for just another 1 or 1.5 seconds. Breaking 500 feet higher and holding the track for a bit longer might help weaker trackers by giving them 2 more seconds to track. 2 seconds don't sound like much but once you are moving, it is a big piece of your overall distance. As you can see, the velocity increase it a pretty steady slope, up. I had to stop when I did because of mother earth. I had not reached full horz speed when I stopped. The Flysight has a tone system you can set for Horz speed, Vert speed, or Glide ratio. So, the "dialing it in", is to know some theory, adapt to the feedback from the tones, while in flight.Instructor quote, “What's weird is that you're older than my dad!” Quote Share this post Link to post Share on other sites
kallend 1,623 #82 September 4, 2012 Quotehttp://www.youtube.com/watch?v=_VW5qzBQQlI I think those guys are doing a pretty good functional track away from a 4-way. Start video about 55 seconds to see their breakoff. nobody dives away everybody stays on level pretty much. Nice way to miss the point completely.... 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
kallend 1,623 #83 September 4, 2012 It's pretty cool that someone is actually making measurements of this stuff. I am particularly interested in the rate of transition from vertical descent to the steady state track, and how it is affected by technique.... 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
JohnMitchell 14 #84 September 4, 2012 Quote It's pretty cool that someone is actually making measurements of this stuff. I am particularly interested in the rate of transition from vertical descent to the steady state track, and how it is affected by technique. Agree, and agree with your earlier post that initially being tilted more head downward would be beneficial to early acceleration. Considering what a poor airfoil the human body is, though, I think the AOA range is fairly large and not as critical as a real wing. Thanks for watching this thread. I know you're a damn good tracker and an excellent critical thinker. Quote Share this post Link to post Share on other sites
dthames 0 #85 September 4, 2012 Quote It's pretty cool that someone is actually making measurements of this stuff. I am particularly interested in the rate of transition from vertical descent to the steady state track, and how it is affected by technique. I would say I have no specific technique but looking at two specific log files, I see about 17-18 seconds of steady acceleration. In one case the horz speed dropped because of a turn. In the other case it dropped because of breakoff alt. I will have to go back and do more test and push it hard from the beginning in a straight line to learn any more. And I still can't control my body to the degree to do a really good job. About tracking distance like breaking off from a RW jump, adding up the numbers I got the following distances covered verses time. Take note that I already had a speed of near 10 MPH, so this is slanted. Actual distance from relitive zero speed would be worse still. Total distance traveled after specific timeframe.... After 1 second, 16 feet After 2 second, 43 feet After 3 second, 79 feet After 4 second, 125 feet After 5 second, 179 feet After 6 second, 239 feet Here is something all can laugh at. Exit, turn west (toward right wingtip) and track. Somehow I managed to get the general direction correct in spite of getting spun. http://youtu.be/BNRiZ_rfwqwInstructor quote, “What's weird is that you're older than my dad!” Quote Share this post Link to post Share on other sites
dthames 0 #86 September 6, 2012 Quote It's pretty cool that someone is actually making measurements of this stuff. I am particularly interested in the rate of transition from vertical descent to the steady state track, and how it is affected by technique. If anyone is interested, here is some data from 2 jumps this past weekend. I am on the bottem end of the learning curve, but each jump I was learning. The dive plan is to exit, turn 90 degrees to the jump run, track hard for about 30 seconds, then ease up a bit. These first 2 jumps I didn't get a full 90 degrees but later I made adjustments and did better. http://pyrodan.privatedata.com/skydive/tracking/tracking-data-sept-1-2.pdfInstructor quote, “What's weird is that you're older than my dad!” Quote Share this post Link to post Share on other sites
kallend 1,623 #87 September 7, 2012 QuoteQuote It's pretty cool that someone is actually making measurements of this stuff. I am particularly interested in the rate of transition from vertical descent to the steady state track, and how it is affected by technique. If anyone is interested, here is some data from 2 jumps this past weekend. I am on the bottem end of the learning curve, but each jump I was learning. The dive plan is to exit, turn 90 degrees to the jump run, track hard for about 30 seconds, then ease up a bit. These first 2 jumps I didn't get a full 90 degrees but later I made adjustments and did better. http://pyrodan.privatedata.com/skydive/tracking/tracking-data-sept-1-2.pdf Interesting. Looks like you are getting a pretty good glide ratio. I think it might be more useful to wait some 10 - 12 seconds before turning to track, so that your inherited speed from the plane will have bled off and you'll be starting essentially from zero horizontal velocity - just as if you were tracking off from a formation skydive.... 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
dthames 0 #88 September 7, 2012 QuoteI think it might be more useful to wait some 10 - 12 seconds before turning to track, so that your inherited speed from the plane will have bled off and you'll be starting essentially from zero horizontal velocity - just as if you were tracking off from a formation skydive. Here you go. Jump 3 in this file, http://pyrodan.privatedata.com/skydive/tracking/tracking-data-sept-1-3.pdf. Notice the nice ramp on the horizontal velocity.Instructor quote, “What's weird is that you're older than my dad!” Quote Share this post Link to post Share on other sites
hillson 0 #89 September 7, 2012 link doesn't work Quote Share this post Link to post Share on other sites
kallend 1,623 #90 September 7, 2012 Quotelink doesn't work Remove the period after "pdf" and it works.... 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
hillson 0 #91 September 7, 2012 QuoteQuotelink doesn't work Remove the period after "pdf" and it works. need coffee before i type. good grief. Quote Share this post Link to post Share on other sites
kallend 1,623 #92 September 7, 2012 QuoteQuoteI think it might be more useful to wait some 10 - 12 seconds before turning to track, so that your inherited speed from the plane will have bled off and you'll be starting essentially from zero horizontal velocity - just as if you were tracking off from a formation skydive. Here you go. Jump 3 in this file, http://pyrodan.privatedata.com/skydive/tracking/tracking-data-sept-1-3.pdf. Notice the nice ramp on the horizontal velocity. Looks like it took some 15 seconds to accelerate to your highest horizontal speed and best "glide ratio". Suggests to me that there is an advantage to adjusting one's angle of incidence as one accelerates.... 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
popsjumper 2 #93 September 7, 2012 Everyone, please take note: This is a young jumper doing all this. Dan is one of the good ones. Extremely impressive, don't you think? Not all young jumpers are to be ignored and snubbed. It's wonderful to see you guys communicating with him as you are. You rock, Dan!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
Sky_doggy 0 #94 September 7, 2012 Hi Dan, What are you using to collect your data & plot your data ? Cool stuff BTW. If you want to see some examples of good body positions, try looking at some of the Olympic Ski Jump runs. Cheer, Paul Quote Share this post Link to post Share on other sites
dthames 0 #95 September 7, 2012 QuoteKallend wrote...Looks like it took some 15 seconds to accelerate to your highest horizontal speed and best "glide ratio". Suggests to me that there is an advantage to adjusting one's angle of incidence as one accelerates. Do you mean get more aggressive with your angle right at the beginning? On that third jump I never got to the max horz speed. I had to start slowing down, find the DZ, and get ready to pull. The curve never did flatten out at the peak. Late in the track something good happened. I think I got more rigid in my legs and feet. The flight was very smooth and just felt right. Pops, you make me blush. I am just trying to study how all of this works. Besides it gives me something to mess with during the week. I do wish you could convince my back that I am young. The data was collected with the Flysight GPS unit. I also had it set in Glide Ratio mode and was using the audio feedback to help me adjust my flight. The graphs and ground track image are from the Flysight viewer. http://pyrodan.privatedata.com/skydive/tracking/tracking-data-sept-1-3.pdfInstructor quote, “What's weird is that you're older than my dad!” Quote Share this post Link to post Share on other sites
runningman 0 #96 September 7, 2012 Quote***Suggests to me that there is an advantage to adjusting one's angle of incidence as one accelerates.*** What do you mean by angle of incidence? Did you mean angle of attack? That bit confused me a little. Quote Share this post Link to post Share on other sites
rehmwa 2 #97 September 7, 2012 QuoteQuote***Suggests to me that there is an advantage to adjusting one's angle of incidence as one accelerates.*** What do you mean by angle of incidence? Did you mean angle of attack? That bit confused me a little. google is friendly for this type of thing ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites
kallend 1,623 #98 September 7, 2012 QuoteQuote***Suggests to me that there is an advantage to adjusting one's angle of incidence as one accelerates.*** What do you mean by angle of incidence? Did you mean angle of attack? That bit confused me a little. OK, sorry for the confusion. Without hard data this is all speculation, but I EXPECT the best way to get good separation is to fly at the angle of ATTACK that maximizes the magnitude of your lift vector. Since your path with respect to the ground is flattening out as you accelerate (and glide ratio increases) this would require a body angle relative to the ground that changes (and flattens) as you accelerate in the track. Nice that Dan is willing to do these experiments and share his data. Motivating me to put my Flysight on my RW helmet.... 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
hillson 0 #99 September 7, 2012 As it is the weekend (pretty much)...any thought of doing a 2-4 way and using your gadget to get some data re: breakoff to pull? Quote Share this post Link to post Share on other sites
popsjumper 2 #100 September 7, 2012 Quote Nice that Dan is willing to do these experiments and share his data. Motivating me to put my Flysight on my RW helmet. I'd like to see some caparison with experienced people...I'm sure Dan would, too.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
