|Tracking Contest at Quantum Leap|
On Saturday (July 24, 1999), a tracking contest was organized at the drop zone and I was asked to participate. Because my freefly student was interested as well, I thought we could do some 2-way tracking RW instead of seriously competing for first place. On my load, there were originally 4 trackers and other trackers on another load. Then, the top two finishers of each group go on another load to race one another. Tracking with 3 other people didn't seem like it would be too much for novice tracking RW. Then, my tracking group turned to be a total of 6 people. The organizer really wanted us to race.
4 of us take a floating position outside the door and 2 diving out from inside. I take rear float so I can see everyone. But the count wasn't visible and I knew they were going as they were peeling off the plane. I leaped, bumping into one other. I was going to fly with the highest tracker assuming everyone is near one another. If my freeflying student was going to be lagging back alone, I was going to join him for tracking RW. However, immediately upon the disorganized exit, I lost 2-3 of the trackers from sight--they were wearing dark colored jumpsuits that more easily camouflaged against the ground. I immediately saw one tracker, Steve, beginning to float and move quickly. I set out after him. I am wearing my white Body Sport freeflying suit. It has kinda baggy arms and legs but not excessive for a freeflyer. As I begin to adjust my relativity with Steve, the others had long diverged from us into a much steeper descent angle with much less forward motion. It was clear that looking out for clear airspace to open wasn't going to be an issue other than to peel away from Steve at the end. As I follow Steve, I have thoughts on how it would be nice to move right along beside him and dock my right hand to his left hand. This is a new kind of sensation to control my relativity in tracking. It was most easy for me to have relative altitude. However, I was weaving from side to side. I made a pass over top his back to the other side and then back again. But I need more practice to refine my proximity control such that I would be able to touch his hand. Then, at one moment, I was over him but slightly forward looking back at his leather hat. His head bent forward looking towards his feet. He was really wanting to track well and every muscle in his body was devoted to it. I knew it was nearing the designated 4,500' stop tracking break off altitude and I didn't think he knew I was there. I was flailing a little bit too much to have yet maneuvered within his visual range beside him. I positioned myself to his left again and then he saw me. He told me that he thought he heard me shout! Yes, I knew that because then he started to refine his body position a little bit more. His forward speed was now such that it was challenging for me to stay there. It was more important that I do not error with my balance and to have my weaving reduced to a minimum. Previously his forward speed was slow enough that I could keep with him with my excessive weaving side to side movement. He was one body length in front of me and I wanted to get aligned beside him again. I steepened my track angle to accelerate my fallrate a little so that I could "flare" it and try to get forward one body length. I didn't get it made up. At that moment, he stopped immediately. I sailed on past so quick while he was waving off.
So it is us two, me and Steve, to race against the two winners from the other group that raced on a previous load.
With only now 2 actual relative tracking dives in my logbook and wanting to have more practice, I wanted to do tracking RW again. After telling Steve about his nice track and my fascination about tracking relative to him, I asked him who he thought was going to be the king tracker. He told me it would probably be the drop zone operator, Jim Cowan. During the climb to altitude, I was a little concerned that the other 3 trackers would be concerned with racing and that I may not be able to work with tracking RW due to their tracking efficiency.
I again get to have the rear float position. I figure if I set my goals on Jim, I'd surely get to do relative tracking flight with one of the other slower ones. Again, I didn't get the exit count exactly right and bumped someone on the exit. And then I saw Jim taking off right away into his track. He was pitched maybe 30-40 degrees head low and I jet after him. I was off to his left side so not only was I to cover horizontal forward distance, I had to cover some lateral distance as well. Jim was tracking efficiently enough that I really kept my mind on slow and smooth such as to not overbank my body and I slowly covered the horizontal forward distance and the sideways distance. About mid-way in my closing, I became conscious that the other 2 trackers had fallen away below in a steeper angle of descent and behind us. That included Steve. I more smoothly lined up beside Jim. Jim looked at me, smiled, welcoming me to his airspace. It was a pleasant moment. He then wiggled his hand with his fingers out. I did not do the same--I was overly occupied with my task of fixing relative control. I think I could have gone over him to the other side but I had less "head-room" to play with. Jim did have one goal, a race to win. He raised his seat up more. Interestingly, this slowed his fallrate only with no change in the rate of forward motion. I readjusted my body, more reverse arching and pitching slightly more head down to maintain the relativity. How I had my arms adjusted felt more important too. Unlike my experience with Steve at the bottom end of the previous dive, I still had a little more range. I could have slowed my fallrate more and I had the option to add some more forward speed too. The sound of the relative wind was way different--I don't remember ever hearing it like this before. I don't know how to describe it. I continued to keep my relativity with Jim. I had my Dytter set to 5,500 to remind me to check for the others to insure I diverge to clear airspace by 4,500 to prepare for deployment. But the other two were no where around. My Dytter went off and a few seconds later, Jim and I, like two fighter planes, banked off to the side peeling away from one another. It was pretty neat. Jim declared me the winner since he could see that I had more capacity left to just jet forward yet more. I selected a pair of goggles from the DZ store.
Concluding Remarks from Quantum Tracking Contest
There is more to understand about tracking.
During the tracking competition the others were not trying to fly relative to me. For this reason, I realize that the oscillating weaving PIO (pilot induced oscillations) will seem worse during dives during which the other tracker will also try to fly relative to me. Since a tracking RW partner is likely to be another novice, I suspect that he will experience the same difficulties with PIO as I had. Jim being a more efficient tracker, PIO was less of a factor since any weaving would make it more likely that I would fall behind. It can be easier to fly relative in a position close to the end of your range.
At the time Steve increased his efficiency at the bottom of the first dive, it was more difficult by a small margin to follow Steve's forward motion at his faster fallrate than it was to follow Jim's forward motion with his slower fallrate. However, when I followed Jim, Steve was left significantly below and behind! There was a large difference in the effectiveness of Steve's and Jim's tracking, yet Steve's was slightly more difficult for me to follow during the last 1,000 feet. Prior to the last thousand feet of tracking, Steve's track was easier to follow with the exception that I discovered how easy it was to find myself weaving back and forth due to PIO. Because I did not see him during the second dive, it is unknown to me if Steve had tracked with his more efficient position that he had utilized for the last 1,000' of my dive with him in the first dive.
Two tracking positions of equal difficulty level in terms of the muscle strain involved can be very different in their level of efficiency and effectiveness in covering horizontal ground. By tracking relative to another competitor, I am able to observe his technique while at the same time being -forced- to modify my fallrate as well as forward motion to maintain the relativity. My effort in maintaining the relativity defaults me to use a tracking position that is at least as effective as the one who I am following. So, would I have tracked as far as Jim solo? Since I had not previously explored adjusting the efficiency of my tracking, Jim's aerial companionship helped me to actually experience his level of efficiency.
So what determines how efficiently one can track?? Steve weighed in at 185 lbs and was wearing a relative work jumpsuit with tight arms and booties. Jim weighed in a little heavier and wore a jumpsuit that was more like coveralls with grippers. I weighed in at about 120 lbs. (All weight given without gear. I figure about 20lbs more for the gear.) I wonder...is it an advantage to be a light weight? And does that make Steve and Jim far more efficient trackers in order to carry their weight across the distance in their track?
My friend, Vladimir Milosavljevic, from Yugoslavia with an extensive engineering background had some ideas to share. For the same control surface at the same fallrate, it is an advantage to be a light weight assuming other factors are equal. Meaning a light weight has the same "steering force" and, because they have less mass, they can have greater acceleration in accordance with Newton's second law of motion as described in the equation a=F/m where a is the acceleration, m is the mass, and F is the steering force.
However, light weight skydivers usually also have a smaller control surface because their bodies are smaller. Their smaller bodies produce proportionally less "steering force." Thus, acceleration will remain the same.
My friend Vladimir continued to explain that carrying extra weight will not cause the acceleration or maneuverability to change. There will be greater air pressure against the body due to the increased airspeed and the mass will be greater. Greater air pressure offers more "steering force" that makes it possible to move more mass. Since both the air pressure and mass are directly proportional to each other, there is no change in the maneuverability.
In reality, human bodies are not perfectly proportional, so one skydiver will have advantages over another for achieving an efficient track. For example, a skydiver with proportionally longer legs will have an advantage.
Perhaps, carrying additional weight adds an advantage or disadvantage for gliding at the maximum speed. This would arise due the drag resulting from the forward direction. However, a soaring plane's weight doesn't affect its gliding distance (in no wind condition!). There may be some exceptions.
Vladimir also told me, "By decreasing your stability in the tracking position by rolling the shoulders forward, lowering the hands, and raising your seat, you can significantly increase your horizontal speed while maintaining the same or even slower vertical fallrate. This increases your gliding distance. However, making yourself even more unstable by dearching even more (such that you could easily tumble onto your back) will not increase your horizontal speed due to the increased drag opposing the forward motion. When Jim raised his hips yet further and his rate of forward motion did not increase, the steering force and the horizontal drag were equalized. Because this decreases your fallrate, your gliding distance will be extended further. In other words, dearching a little bit will significantly increase the horizontal speed since the horizontal drag is not significant. To achieve the maximum gliding distance, the center of pressure must be below your center of gravity.
|How Does The Average Jumper Track?|
However, the question "how does the average jumper track?" still remained to be answered. At the 1998 freefly festival held at Skydive Arizona, I had two opportunities to find out.
The first was that I was asked to participate in my first tracking RW jump. I wore my white Body Sport freefly suit. During this tracking RW dive, the dive leader set the tracking pace as he tracked on his back with the rest of the group following. He adjusted the efficiency of his track so that the slowest person could keep up with the group. As I tracked, I found the forward motion of the group to be much slower and the fallrate to be much faster than my comfort range. While tracking on my belly, it was all too easy for me to find myself jetting out in front of the group and being floaty. I reduced my floaty fallrate problem by putting my hands and forearms behind the burble of my rig (and that makes it impossible for me to reach for a grip if I desired). I could have also tried tracking on my back too. So, I realize that wearing a sweat shirt and jeans would have been a better match for this dive. The dive leader reported that he had to track a little slower than usual due to some low skill level people on the dive.
Secondly, I was asked on a tracking contest at that freefly festival. However, everyone did it solo just looking at the ground so it was not nearly as fascinating as my Quantum Leap experience was. Each tracking competitor had to track straight to the South which was towards the DZ and ensure that they went straight south without deviating off to either side to avoid entering other competitors' airspace. This is accomplished by looking down at the ground and making sure that you're tracking exactly parallel to the North-South roads and field divisions. During this competition, I wanted to find out how many would be behind me and how many would be in front of me, if I used a comfortable tracking position without any muscle strain. That's right, I was not trying to put every muscle into it. I was testing to see if I, in general, had a tendency to track too much in order to participate in tracking RW on the average. When I opened, most of the tracking competitors were behind me and a few really good ones in front of me. This shows me again that I probably should use sweat shirt and jeans for tracking RW.
The Quantum Tracking contest suggests similarly. With my white Body Sport suit, I was tracking relative with some of the best of Quantum's trackers while the others just fell away below and behind. And I was starting to have trouble with PIO on the first race with Steve. If I want to do tracking RW with the average folks of the DZ, I probably need my jeans and sweat shirt. Yeap, RW is about coordinating with everyone's fallrates and motions.