fred

I'm curious, Luna, but do you have any idea what made it finally "click"? I remember one of my best jumps in my SL program, it was a 10 or 15 second delay, and it was in the evening, and the sun was starting to set. I got out of the airplane, got stable, and there was a low front of clouds coming in on the horizon, and the sun was setting right over it. So there I was, staring at the top of clouds, and I didn't want to look away. As I started turning (which was my big problem as a student), I just said, "Nuh uh... I want. to look. there", and I maintained my heading. And then pull-time came. I did a couple more jumps on SL, and failed them because of spinning. But then, when I did AFF in Arizona, on my second jump there, I noticed the mountains in the horizon. And suddenly, I could actually keep a heading. That (and a few other things) really helped me pass AFF.

In another thread (and I considered continuing this discussion there, but it seems ripe for its own thread), Hooknswoop and Kris both agreed that: ... and that it wouldn't naturally turn down-wind. I'm not saying that I don't believe this, but I'm skeptical. I think it's simplifying the physics and the weather. But I think there are techicalities that make this untrue, and I wish to explore them. First, I understand completely that a freestanding body in a fluid will eventually (quickly, in skydiving terms) start moving at the same speed as that fluid. I have no idea how long it takes a skydiver to reach this point, but I imagine it's well before pull time. Assuming that's true, at pull time, the skydiver and the parachute open in this fluid, and are moving at the same speed. Thus, it doesn't matter if this winds are dead still or if they're flowing at 50mph, the canopy will behave the same. It seems a lot of skydivers don't get this point, but groundspeed has no affect. I think hooknswoop, kris, and others will agree with me up until this point. But this is where I lose it. Wind does not have a constant speed. Experience on the ground tells me that wind is, in fact, constantly changing speed. Wind gusts, and breezes, and dies down, all within a couple seconds. For every change in the fluid, the canopy must try to catch up. The canopy has more mass than the surrounding particles, thus, it requires more force to make it slow down or speed up. Certain parts of the canopy will catch more or less wind resistance, and the resultant force from friction will affect it in different ways. Further, I'd wager that the front of the canopy has more resistance than the back, and thus, will be affected more by changes in windspeed than the back, making the canopy seem to turn downwind. The possibilities: (1) The wind at higher altitudes does not change speed as much as that near the ground, thus what I experience while standing in an open field is much different than the wind at opening altitudes. I'm willing to believe this, if anybody can verify this, I'd be much obliged. (2) The effects of changes in the wind cancel out. That is, wind increasing speed turns the canopy downwind, but it then slows again, turning the canopy back upwind. This is possible, but only if gusts were sustained long enough for the canopy to once again reach equilibrium with the fluid it is traveling through. I tend to think that gusts don't last long enough for this to be true, but again, I don't know. (3) The effects are negligible. Again, I just don't know enough about wind. In my experience, stronger winds supply stronger gusts (at ground level), if this holds true for higher altitudes, I find it hard to believe that the effect is negligible. (4) I am right, and it is conceivable that in 3 minutes of descent, changes in windspeed could make the canopy point downwind. I'm always trying to learn... And I'm certainly no skydiving champ (I would describe my skills as pre-beginner), but I also think I have a pretty firm grasp of physics (except magnetic flux, which has always evaded me), and I feel like a lot of the 'experts' simplify the physics so much that their explanations based on them are inaccurate at best, and sometimes misleading. I hope I explained that well enough... I'll be ecstatic if somebody can explain to me the fallacy in my logic.

I was transitioning from SL to AFF, and in my SL program at 10 sec delays we still weren't taught to wave off. So he told me, probably 3 times, that if I did happen to just go to pull without waving off, I should just pull. "Don't," he said, "Don't stop your pull to go back and wave off." Naturally, 5500 hit, and I reached for the ripcord, touched it and thought, "Damn, I'm supposed to wave off!" Waved off and pulled. I was quite surprised he passed me.

This is interesting. I've got friends at the blood center who might be interested in organizing one at my dropzone. How does it work? Do people donate throughout the day and then get on airplanes shortly after? Or is it an evening thing? Somehow, I feel like donating blood and then jumping out of an airplane later that day is a bad idea.

Looks like a wonderful toy. I think the graphics on skycat's website are broken, though. This has been added to my 'wish list', however.

Isn't 10 declared jumps within 10m of the target the requirement for a PRO rating? Billvon, are you seriously suggesting that the first time a jumper downsize should be sometime after they get their pro?

Isn't that like a year's salary for an AFF instructor?

I've also been working on an online or web-based jumplog, but I really want to be able to import directly from my protrack. So far, while I can easily get the data the protrack sends to the computer, I can't make heads or tails out of what it's sending. They seem to use some formula in their software to translate the collected numbers into actual altitude, and I have yet to find out how to decode it. Mind you, it's been a few months since I've tried. If anybody has any information on this, I'd really appreciate a PM or an E-Mail (I believe it's viewable in my profile).

Does this mean they have rental gear available? Skyrose, let's go!

Congratulations to those who made it. Rumour has it that they're trying for bigger tomorrow. Apparently they spent today dirtdiving a 328-way? My parents are planning on going out there to watch... Hopefully they'll take pictures.

Reading this and the other thread, I've still got questions. It seems that most canopy manufacturers will readily send out demo gear for a couple weeks, but how does that work for a first-time jumper? I certainly don't have a container to put the canopy on, but would very much like to know how, say, a Spectre 200' compares to a hornet of the same size. Are there places that will ship complete rigs for trial? Sure, it would be really nice to live next to one of the Squares and try things out there, but I don't. And how about testing rigs? A lot of manufacturers and people posting here talk about how Rig A is more comfortable than Rig B. How can a newbie tell? \

You can download the sim from uspa.org in PDF format. And remember, there's more to skydiving than licenses. Remember to have fun.

Just send me an email. I've got more than 50 jumps, so I'm an expert. I'd be glad to answer any questions... Seriously, though, Dropzone.com has a lot of valuable information, you just have to learn how to filter out the good stuff from the bad. Pay attention to what people say and put some effort into understanding the 'why's about their opinion. There are some very smart people on this forum who have a lot of experience to share. There are also some very loud people who post often and authoritatively, but actually have no clue. Read the explanations as well as the answers. And then someday you can become an expert, like me. ;)

Does anybody have good pictures of the difference?

Just to let you know, it works both ways. I'm 5'11" and 210#, and I fall like a dart. If I jump in my normal arch, I could keep up with most of the sitflyers at my dropzone. I definately understand the frustration, in that I feel that my fall rate is holding me back. For me, it's getting better. I'm slowly learning how to spread out while maintaining control, but it's taking time. I don't have any advice, except to offer the same mantra that I've been using. It will get easier with practice.

Let's see. Started playing trombone when I was in 6th grade... Played through graduation, so 7 years total. I was consistently first chair, and could rock, so long as the music was written for me. I did 4 years of Jazz Band, but, while I know the basics about improv, I always had my solos written out for me (and, actually, tried pretty hard to talk my director into letting me play 4th chair/bass trombone, because kicking out those low notes rocks, but unfortunately, I was about the only one who could even hit the 1st chair notes). I did pit orchestra for the high school musical for four years. I don't remember if it was "Once Upon A Matress" or "Annie", but that was the hardest sheet music I ever came across. No high school student should ever have to deal with double sharps. Let's see... pep band, city festival, parades, epcot, and disney... I was a true band geek. My junior year I became drum major of the marching band. This is probably the reason I couldn't continue on in college. I loved directing the band; I liked the fact that when I made a mistake (which I did a number of times), I could actually hear the results. Nothing like watching the horn section try to keep up when you're about 40 bpm faster than the song's supposed to be.

When I first returned to my 182 dz after doing AFF out of Otters, I asked about diving exits. The first instructor I talked to said, "Usually, I dive straight out of the door, but once, I hit my knee on the step, and ... well... you'd better hope you never do that, because it hurts." 30 jumps since, I've never found the courage to jump straight from the door without putting my left foot out on the step.

Must say, I'm with markbaur here. The "Pull, Pull at altititude, pull stable" mneumonic needs to be retired. I'm a generally smart guy, and I didn't understand it until I discussed it on this board. The idea is fine, and, imo, absolutely correct, but two students it's too close to: "3 criteria you need to get a good parachute" instead of "this is the order of importance."

I can't cast a vote. The actual "student" rigs (that is, what first jump students wear until graduation) have an FXC. We're taught pretty early on how to check the calibration and so forth. After you graduate, you take transition training, and get a course on using the BOC instead of ripcord, the two-handled reserve procedure (instead of SOS), and the Cypres. You then jump transition rigs until you get your own gear. So the DZ's gear has both FXC's and Cypres (cypri?), depending on where you are in the training.

Also, her website is registered in her name, so anybody with above average internet prowess can get her full name and contact information.

But clearly not well-understood. There's so much misinformation and misunderstanding in this thread... I find it frustrating to read. The answer to the original question is simple. It takes an average person about 12 seconds to reach terminal velocity from an average airplane at an average elevation/temperature/pressure/humidity. Gravity is a force that acts between any two objects of mass. As with all forces, there is an equal attraction between the two objects of mass, and this force is directly proportional to the mass of the two objects and inversely proportional to the distance between them. (equation is: F=G (M[1]*M[2]) / R^2, where F is the force, the M's are masses of the two objects, and R is the distance between them). In the end, it's not even this simple, since most objects with mass also have volume and you get into some pretty complex calculus to determine the 'exact' force of attraction. So, given that M[1] is the earth, and M[2] is a skydiver and assuming the difference between 0AGL and 10,000ft AGL is insignificant, we find that a skydiver and the earth have a mutual attractive force of approximately M[2]*9.8 m/s^2. Note that "Weight" is a measure of force, not mass. Thus, I exert a force of about 210 lbs (approximately 938 N) toward the earth. In the absence of any wind resistance, this force does not matter. F=MA is our friendly equation here, and we can establish that because of the relationship between F and M, A remains constant for the (simplified) case of earth's gravitational field. (Altitude will affect the value of A, but it will remain constant for any given M at that altitude). Then we have drag. I've never been exposed to the actual mathematics behind it, so anybody is welcome to fill in details here. The drag force is proportional to the square of the velocity and a reference area, and is affected by a number of other factors (air density and viscosity, etc, etc). It exerts a force against whatever is causing the drag. So as we fall through the air, we exert a (mostly) constant downward force (in my case, 938 N), while drag causes an opposite upward force. After leaving the airplane, my speed increases rapidly because my downward force is much greater than the force caused by drag. But drag catches up exponentially, and as I accelerate, it causes greater and greater upward force until the point where the drag force is exactly equal to the force due to my mass. At this point, I have reached terminal velocity. By changing the reference area presented to the wind (and thus subject to the drag force), I can increase or decrease the force provided by drag, and the process repeats itself. Either I slow down until the forces match, or I accelerate until they do. I don't expect that many of you read this far, but here's a nice example that I enjoyed from my physics textbook. Numbers may have been changed to protect the innocent. Inner city cats have a habit of falling off of fire escapes and window ledges. Over the years, information has been collected and compiled from various NYC veterinary hospitals about the height of the fall and the extent of the injuries. An interesting trend appeared. As heights increased to about 8 stories, the injuries to the cats increased proportionally, as would be expected. However, above 8 stories, injuries actually decreased. Thus, a cat who fell from the 11th story had a much better chance of survival than one who fell from the 7th. So why is this? It has to do with how animals sense motion. We don't feel velocity, but only acceleration. This is why we get that stomache feeling when we go on a rollercoaster but thankfully don't feel the spin of the earth (or, if you were in a closed room falling at terminal velocity, you would have no idea that you were actually falling). So, during the first 8 stories, the cat feels the acceleration, get's frightened, and curls up into a tiny ball. But after falling for 8 stories, the cat reaches terminal velocity. At this point, no longer feeling the acceleration, the cat begins to relax, and actually spreads out. This increases it's apparent area, thus increasing drag, and reducing it's terminal velocity. Voila, a slower falling cat has fewer injuries.

I've never seen static lines except for those at my dropzone, but how do you miss something like this?

If you really want to do AFF/AFP, I believe both Napoleon and Tecumseh offer programs, as well. Or Skydive Chicago isn't too far from the Michigan area, and I believe they're open pretty late into the season. Like Billvon, I went from a SL training program to an AFF program (Winter vacation in Arizona), and graduated pretty quickly. The switch was pretty easy. They gave me about 1 1/2 hours of "refresher"/"Transition" training then put me on a "checkout" dive where all I had to do was fall, so that they could evaluate where I should be in the program. When I came back to my home DZ (Great Lakes Skydivers, btw, if you want to consider going the SL route), they had me do the normal jumps for an out-of-current skydiver, and then released me to solo.

If a student's still under canopy, and they're in a situation that clearly calls for a cutaway, then it is the instructors responsibility to instruct the student to cutaway. If the only reason an instructor wouldn't say something is because, "Hey, I might be sued." ... Well, it's one of the few cases where I think an instructor should be sued. It is gross negligence. I agree with others, though, that there may be legit reasons why an instructor wouldn't want to recommend a cutaway. Another student on the same frequency, lower to the ground, for instance. But I think, "Student number 4, if you cannot control your canopy, you should cutaway" is still generally safe. All I have a problem with is the idea that some instructor wouldn't instruct a student to cutaway for the sole reason that their ass may be on the line.

First, talk to your jumpmaster about your gear. Ask him what happens during deployment, and then what happens during cutaway, and reserve release. There's a lot to learn about the gear, but in the end, it's all very simple. Before you gear up, you should be checking your rig to make sure everything looks right. When you open the main closing flap, you'll see a closing pin or ripcord going through the closing loop. The closing loop is attached to the rig, and holds the main container closed. (It is not attached to the closing pin, btw, and in fact, that would be very bad). When you throw out the pilot chute, it catches air and extends the bridle. Along the bridle, the closing pin is attached, and at an appropriate distance, the pilot chute pulls out the closing pin from the closing loop. This opens the main container so that your deployment bag and main canopy can come out. The pilot chute keeps pulling the d-bag until line stretch, at which point the main canopy comes out of the bag. Hopefully, it inflates, and saves your life. If not, there's another closing pin on your reserve. This one is pulled by your reserve handle directly, and a spring-loaded pilot chute will be ejected from the top part of your rig, pulling the reserve bag "freebag" out, and allowing the reserve to inflate. Big difference is that the d-bag on your main is attached to the canopy, whereas on the reserve, it will fall free once it has released the reserve. (Hence the term, "freebag")... (standard disclaimer: I don't have many jumps, and there are many exceptions to this description, so your equipment may vary).