winsor

IIRC, that should be the square of the velocity. Blue skies, Winsor

Elliptical X-braced Tri-cell (reme) - I'm not sure of the FX vs. VX part of the nomenclature. I agree that the term is hackneyed. I can see its limited use when applied to near-death-experiences where one is really working without a net, but the idea of extreme checkers or extreme typing or something is a bit much. It's kind of like "sporty" cars with fake hood scoops and brake vents - much of the reality fails to live up to the promise. "Extreme" is strictly from Madison Avenue, which is not at all what this sport is about in the main. Blue skies, Winsor

I have three CYPRES-equipped rigs. I also have maybe a dozen that are AAD-free (though many of those are CYPRES-ready). The two I took to the DZ yesterday were of the manual variety. I am somewhat indifferent as to whether the rig I'm using has an AAD. If it has one, I turn it on. In any case I consider it a good idea to keep pulling handles until something landable is overhead, and to do so with sufficient altitude to have a good chance of success. It is typically better to forget to turn it on and leave it off than to remember on the ride to altitude and turn it on then. I once remembered to turn on my CYPRES as we climbed through 3,000 feet, then thought "wait a minute!" and turned it back off again. Someone who did so but left it on had a reserve ride out of a formation, so I'm glad I rethought the matter. Blue skies, Winsor

Slugs. Do them up with butter and garlic, put them in a snail shell and voila! L'escargot! Blue skies, Winsor

My reserve to main transition altitude is a function of canopy in use and venue. If I'm jumping one of my EXTreme FX 99s in Lebanon, ME, where outs = big trees, I might not go to main below 3 grand unless I was sure I was over the DZ. If I'm jumping one of my Raven IVs at Perris, I might use the main at 1,200 feet. I'll be under canopy above a grand and I can sink it in just about anywhere. The decision altitude should be part of your preflight. Blue skies, Winsor

I think it would be best not to try to cut a line over in a spinning reserve, scares me more the idea of cutting a wrong reserve line than going down to the floor with a spinning reserve. Maybe somebody with more experience can tell me more about this. Since the offending line is almost always a steering line, simply cutting the steering line on trashed side will likely address the problem. If you had to figure out which suspension line it was, you probably couldn't do so before the ground intervened. Blue skies, Winsor

Even though I carry multiple hook knives as a matter of course, I don't view it as a panacea. I have cleared a lineover (on a main) by briskly hauling down on risers on the offending side, which caused the line to pop free. Since reserves tend to be low aspect ratio 7 cells, they are not subject to the wild spinning you might find on a hot elliptical, but it is still a good idea to stay the hell away from the brakes as long as possible. Clearing the brakes tends to exacerbate any tendency to turn that results from the lineover - on a high performance canopy this can mean going from a mild turn to spinning violently on your back. If you are going to use your hook knife, your best bet is to cut the steering line on the fouled side. The steering line accounts for almost all lineovers. I would recommend leaving the other side alone and steering with risers. Whatever you do, it is best to do it FAST. You are under your reserve, remember? Thus, you are likely a lot lower than opening under your main, and your glide ratio under a lineover is going to be less than normal (for the reserve). This is a tough bit of advice, but whatever you do - LOOK AROUND! If you fail to maintain an adequate scan such that you fixate on one aspect of your situation, you may have success with clearing the mal only to find that you've backed yourself into a fatal corner. Whenever I chop, I make damned sure I have enough air under me for the reserve to have a chance to open. One last, fast scan won't waste but a second, and may well save your life. Be advised that in this sport, indecision has the capacity to be fatal. Blue skies, Winsor

Tom Piras was an outstanding skydiver too, gold medalist, world record holder... Yeah, and he was one of the few people jumping a CYPRES-equipped rig at the time. Two great quotes came from that jump: "It's only a four-way" (as he turned it off after he demonstrated turning it on). "Maybe I should have left it on" (on the way to altitude). Blue skies, Winsor

I recommend a minimum of two knives on every rig (okay, so I only have one knife on my round rigs), with one mounted high and one low. A Zak knife (cheap orange plastic) is better than nothing, but not much. Aluminum knives are a good standard, and Jack the Ripper types work well. Be advised that the Jack the Ripper types are difficult to unsheathe quickly unless the sheath is sewn in place to a jumpsuit or something - removing it quickly from an unsupported sheath is a two-handed operation, and should be practiced before attempting it under duress. The nice thing about the Jack the Ripper knife is that it will cut through ANY line or webbing on the rig - fast. The down side is that if you're not paying attention, you can slice through the wrong risers or whatever without trying real hard. Keep some kind of folding knife on hand for general utility and dedicate the hook knife to emergency duty. Microline will dull a sharp blade so fast you wouldn't believe it, and you definitely want a virgin blade to get you out of a jam. Don't sharpen the blade. If it's suspect, replace the blade or the whole knife. A couple of low-timers were talking on the way to altitude about doing CRW after opening, and I asked if they both had hook knives. I gave my extra one to the guy who didn't have one. He returned it after landing, and made the investment. I can personally attest that it's better to have one and not need it than to need one and not have it, because you tend to need it rather badly when you do. Blue skies, Winsor

Flip Wilson used to advertise for Sea and Ski, which was seen as a joke at the time (he was a comedian and all). It turns out that he had gone to Jamaica and figured that he was pre-tanned, and therefore immune to the sun. Wrong. While he was hospitalized for sun poisoning (severe burns resulting in histamine overload), the attending physician recommended that he use a good sunscreen. At the time, Sea and Ski was about the best one could find over the counter and he really used the stuff. A friend in High School (not of European ethnicity FWIW) made the observation that has stuck with me ever since - there are only two kinds of people, US and THEM. Quite who is who depends on who is present and what is under discussion (football vs. baseball fans, men vs. women, Liberals vs. Conservatives, Ibo vs. Yoruba, etc.). While in the Army, I once watched the line of demarcation switch half a dozen times over the course of an hour with pretty much the same group present. Groupings were almost random as the issue was Airborne/Leg, Infantry/Armor, Urban/Rural, Yankee/Southern, Homeboy/Honkey, Short-timer/Lifer and so forth. I'm leery of people who put too much stock in one form of catagorization or another. I'm a little more comfortable with people who are slightly indifferent to cultural differences than those who are overly "sensitive." In the skydiving world I should hope that concerns are more here-and-now than generic. I have been on skydives with any combination of gay/straight, Islamic/Christian/Buddhist/Wiccan/Atheist/Other, Narc/Dealer, Democrat/Socialist/Republican/Green/Libertarian and goodness only knows what combination of ethnicity. As long as someone has a good attitude, I'll jump with them. Blue skies, Winsor

For whatever reason, most of the people who gravitate to the sport seem to be males of European extraction. I could speculate as to why, but it wouldn't be all that informed a guess. The most significant line of demarcation appears to be sex. An attractive, single female is likely to be given more consideration than is a male who is not a World Champion. There is a pretty significant gay element, both male and female, but I don't see anyone making a big deal about it. By and large the gay members of the community don't make an issue of their preferences, and they are judged on the basis of their skills and contribution to the community. As far as race goes, it doesn't seem to be much of a factor on the DZ. If someone is being discussed, it is often more of concern if they're a CRW dog or a freeflier than what is their ethnicity. You don't have cliques based on off-DZ concerns so much as by skydiving discipline. The bottom line is that it really doesn't make much difference if your forebears were Iroquois, Indonesian, Ibo or Irish. It does make a difference if you're a good-looking woman. Blue skies, Winsor

Definitions vary, but hooking can mean failing to complete a hard turn before arrival. The best way to back yourself into a corner such that you impact under a perfectly good canopy usually inolves burying a toggle when too low to recover. If you're interested in high-performance landings, a front-riser turn may allow you to bail if you realize that completing the turn is not possible. By letting go of the riser your turn flattens out, and you can maybe dig yourself out of the corner with brakes. You still have the potential to come to grief with a front-riser turn, but at least there's a Plan B with which to work. Again defining a hook as a turn wherein the planet gets in the way, survival is a function of angle of incidence, speed and the material against which you decelerate. If you're going 80 miles an hour vertically when you hit, you really need to have something like a 30 foot high pile of foam pillows in front of you to have much of a chance. If you can bring it up to about a 30 degree angle at highway speeds, I've seen people get away with not much more than a smashed femur or two. With a butt strike you stand the chance of a crunched pelvis and some smooshed lower lumbar vertebrae and/or blown disks (just for starts). Even if you can level it out, remember to keep flying. People have snapped their necks with the rude face-plant that comes with letting go of the toggles at speed. Being a quadraplegic is not my idea of a good time. Sure, any rigger worth his (her) salt can modify a sail slider to either a kill-line or velcro-wrap collapsible in short order. It's useful to have mini-risers and big enough grommets to get past the links and toggles, since getting the slider out of the breeze helps greatly, whether you collapse it or not. Blue skies, Winsor

Dude, I many not be a physics teacher but I have a 4 year degree so don't try to insult my intelligence with your passive aggresive replies. All your accomplishing is making yourself look like an ass. If you want to talk, then talk like a man, don't act better than thou. It's not an act. As Dizzy Dean said, "it ain't bragging if you can do it." If you want either my credentials or peer review of my contentions, you are welcome to discover how far out of you league you are. A four year degree is all well and good, but you could have a Ph.D. from one school and not qualify to enter another as a Freshman. All schools are not created equal. Actually, I'm not. Most of the policies and procedures used by SF and other elite groups are, indeed, spot on. Others are not so rigorous, and usually these are in matters about which you can't do much. For example, I heard one of the most ill-informed treatises on interior, exterior and terminal ballistics that I've ever endured from an SF "expert," but the bottom line is that operationally he has to bet the ranch on the performance of some variant of the 5.56x45 cartridge, so it's better to believe than to doubt. Did you even bother to look at the power point presentations? The excel spread sheet I posted is part of a bigger equation. However,civillian skydivers don't calc winds so the only thing one can do to try and be as safe as possible is to use a method safer than the 45 degree method or the 4 sec method. If you have a better way of ensuring seperation then put your money where your mouth is and show the rest of us "ignorant" people. Up until this point all you've done is waste bandwidth. If you read the notes to my spotting and separation seminar closely, you'll see why I shy away from any formula that says "do this and you're fine." If you want an instant improvement in your methodology, simply replace groundspeed with airspeed in all of your calculations of horizontal separation. Groundspeed is related only by coincidence. You see, thats where your wrong. Becasue I don't have to defend the methodology, because what you think is not relevant to what I do. The physical model I use works in real life as I stated. We don't have this seperation issue in military skydiving. Can you explain that? Of course I can explain it. There is enough room for error (800 vs. 900 feet, both are "plenty" or "not enough" as the case may be) that using your rule of thumb is better than nothing. If you were working with a system where you had to be on to even two digits of accuracy, you would be screwed. Edited for personal attacks. Discussing exit separation is fine; discussing how pompous/stupid/inferior someone else is is not, whether or not you believe it to be true. Blue skies, Winsor

If you want to LAND 1000 feet apart, this is fine. It has nothing to do with how far apart you are IN THE AIR, which is the frame of reference of interest when we discuss "horizontal separation." Once you select the wrong frame of reference for your analysis, any further effort is wasted. As Bill pointed out, the critical frame of reference is the speed of the aircraft with regard to the airmass at opening altitude. The next most relevant frame of reference is true airspeed. The least useful datum is groundspeed, so long as we're talking about horizontal separation IN THE AIR. What the ground is doing is, in and of itself, immaterial to the behavior of objects in the air above it. Q: If you have a layer of fog up to 2,500 feet and there is a 20 kt breeze on the ground, can you tell which way the wind is blowing by the behavior of groups in freefall above? A: No, the ground winds and ground speed are entirely immaterial, and have no effect whatsoever on the path of bodies THROUGH THE AIR. Blue skies, Winsor

And I make a living of jumping out of airplanes and more specifically putting people out of them safely. I looked at your paper and the only part that I can assume that your prior post would be applicable to would be jumping from a stationary object. Yes there people who understand and I happen to be one of them. Otherwise the military wouldn't of seen fit to award me the responsibility of jumpmastering people into combat. While I don't write the doctrine, there are people who do. We will assume that they are the "ones" you claim to know the fundamentals. What I and every other HALO jumpmaster do every time we jump is what those who "know" have seen fit to make doctrine. Which goes pages beyond what can be said for sport skydiving, which is too bad. You keep teaching physics in the classroom and I will keep putting people out of airplanes the military way, wheather or not you agree with the military method. Funny how we don't seem to have these seperation issues in the military? Your understanding, such as it is, is the classic "good enough for Government work." You simply don't know enough to have any idea how little you know. The Excel spreadsheet you tout illustrates at a glance the level of your ignorance. It's like the Soviets trying to bluff the West into thinking that their new jet bomber was supersonic without any understanding of the Area Rule - it only took one fast look to classify it as a subsonic flight platform. Your procedure is not inherently dangerous, and is better than nothing, but the physical model you use displays a fundamental lack of comprehension - as does your defense of your methodology. Be advised, you're out of your league. Blue skies, Winsor

But if you stretch out the time between groups, you're also stretching out the horizontal separation in the air. In strong wind, that means the first groups to exit will probably be downwind of the dz. Don't you want the same amount of total horizontal space between the first and last groups to be sure everyone can get back? And if increasing the time between groups increases separation unnecessarily, wouldn't that be a bad thing? I'm going to have to take notice and see if there are more off landings during strong head wind when everyone's taking more time between groups. How far apart you are in the air is simply the product of airspeed and time between exits (e.g., 150 fps * 5 seconds between exits = 750 feet horizontal between groups). The distance between no-drift landing points (like with round parachutes) is the product of groundspeed and time between exits (e.g., (150 fps airspeed - 50 fps headwind) * 5 seconds between exits = 500 feet. In the case above, which is like a 90 kt jumprun into a 30 kt headwind (typical), you can have a total of a mile and a half of horizontal separation in the air with only a mile track over the ground. Looking at it another way, assuming you have constant winds from the ground on up (you don't, but it makes it easier to visualize), the first group and the last group are separated by a mile and a half in the air. Between the time the first group lands and the last group lands, the last group will have drifted half a mile, so their landing points are only a mile apart. This is a FOUR dimensional problem - time is an important element. Blue skies, Winsor

Please explain to me how it's wrong so I can tell the Military. If I know how fast the airplane is moving through the air at a given moment and I know what the winds are at altitude(becasue I did my wind calcs and got the winds) I have a general idea of how much the wind is affecting not only the aircraft but the people leaving the aircraft. Hence the calculation of forward throw when computing the HARP. Once I know all of that I can use the ground speed as a reference to figure out the seperation between groups after the first group exits. I may not be a physics teacher but I have calc'd enough winds and put people out of both STOL and High performance aircraft to know that it works in the real world. Read the article to which I posted the url. I have made a living as a Physics Instructor. The Military is hardly monolithic, and I assure you that there are plenty of people in The Military that already understand the fundamentals. You don't (nothing personal, but it's the truth). Blue skies, Winsor

Hmmm.....that brings up a good question. It's often said that longer time between groups is necessary when jump run is into a strong wind. But wouldn't the jumpers exiting the plane be in that same wind? Essentially, the airspeed of the plane is unchanged. The distance traveled in the air over a 6 second period of time is the same no matter what the wind is doing. So, when the first jumper exits, they will be whisked away downwind from the plane much faster when there is a strong wind. So why is it necessary to change the separation time between groups? After 6 seconds, they should be just as far "downstream" from the plane regardless of ground speed. No? This is a classic "frames of reference" scenario that gives Freshmen fits (at least those in a rigorous technical program presupposing a solid basis in Physics). The airspeed of concern to jumpers just after exit is the true airspeed of the jump aircraft. In a free balloon you're looking straight down at whoever just left, regardless of what the ground is doing. The benefit that a headwind provides is the ability to take more time between groups and still have everybody get back (groundspeed only affects WHERE YOU LAND). Thus, with honking headwinds at altitude you can greatly increase horizontal separation between groups above the minimum, without anyone getting hosed (assuming that the person spotting has some understanding of the physics involved there, as well). Blue skies, Winsor

With a lineover, often it will go pretty close to straight ahead until you clear the brakes. Then you can expect to be spinning wildly on your back. This season I have had two lineovers (yeah, I've modified the offending portion of my packing technique). The first was on an elliptical loaded less than 1.2:1, and I cleared it by pulling down the rear riser on the offending side. It just popped out and flew fine. The second was on a cross-braced canopy loaded over 2:1, and it was a solid bowtie. Rather than find out how it would behave if I pissed it off further, I chopped it. In both cases the canopy had a mild turn, but I emphasize DO NOT CLEAR THE BRAKES until you have cleared the malfunction. I assure you that it is much more pleasant to cut away when in relatively normal flight under a canopy you'd just rather not land than it is to sort things out from a violently spinning malfunction. Kicking out of four line twists under a reserve is not my idea of a good time. Blue skies, Winsor

"For every complex problem, there exists a solution that is simple, elegant - and wrong." H. L. Mencken Nice spreadsheet, but the physics are fundamentally flawed. What the ground is doing is entirely irrelevant with regard to separation IN THE AIR. It only matters in terms of where you land. If you wish to pick a critical speed, it is that of the aircraft with regard to the airmass at opening altitude. An introductory treatment of exit separation can be found here: http://dogyks.home.netcom.com/jumprun/jmprun~1.htm. Blue skies, Winsor

I'm not an instructor, so my comments reflect only my opinion. One fundamental concept regarding safety systems is that they should be as simple as possible. Another is that you should change as little as possible in the lifesaving sequence over time. Thus, if possible, the best scenario is to learn a set of safety procedures on day one that will work just fine a thousand jumps from now. I am kind of a chicken, so I don't like going back into freefall unless I have my thumb hooked through silver. The idea of cutting away and then trying to find where the ripcord went when the harness shifted bothers me. My procedure is one hand per handle and I stuff them in my jumpsuit before clearing the brakes on my reserve. To get to whether you should hang on to your ripcord to see if you'd pulled it, this concept puzzles me. The fact that you're still in freefall is usually a pretty good clue that you're not done with your emergency procedures, and I've been known to pitch handles when I had more immediate concerns than hanging on to them. Keep pulling handles until you're under a good canopy, and hang on the handles if you are afforded that luxury, but focus 100% on staying alive regardless. If you're worried about losing the handle, don't sweat it - they'll make you a new one. Anyhow, the most basic cutaway procedure I was taught (when switching to 3-rings from shot and a half Capewells) was two hands per handle, keep an eye on the reserve ripcord while pulling the cutaway, and fling each handle once it is pulled completely. For your first cutaway, I suggest throwing the handles away as a matter of course. Thereafter, keeping the handles is optional, but you should be ready to pitch them IMMEDIATELY if they interfere in the slightest with your emergency procedures (sometimes there's more to do after pulling handles...). Oh, and whatever your procedure - practice it a lot. Having it be second nature really helps in a pinch. Blue skies, Winsor

The speed of sound (in a gas) is a function of temperature only. Sonic velocity varies by the square root of (absolute) temperature. At around 820 degrees Celsius the speed of sound is double what it is at 0 degrees Celsius, which is more of a consideration with regard to maximum piston speed in a recip or blade speed in a turbine than for skydiving in general. However, at -100 degrees Celsius the speed of sound is about 76% of its value at room temperature, going from about 346 to 262 meters/second or 774 to 586 mph. This is all off the top of my head, so don't bank on accuracy to three digits, but the basic idea is sound. Blue skies, Winsor

Well we will just have to hope that the winds are blowing in the same direction that the crop rows are planted otherwise what good does it do to look for signs of wind direction? (eye roll smiley) That bit of advice might be suitable for low/varibale wind days but the last thing one should be worrying about when landing off in a farmers field is if they're landing with the rows. Oh, I have to disagree with that. Needless to say, I've made rather a few landings into a variety of crops, under canopies from rounds to Class V and with crosswinds ranging from nil to substantial. There is a real laundry list of reasons why it is strongly advisable to land with the rows with a crosswind component instead of landing across the rows directly into the wind. If you can sink it straight down between the rows, fine. Otherwise, keep your ground track between the rows until your arrival. Blue skies, Winsor

This has to rank up there with the all time worst advice. Could you please elaborate with how the suns position dictates which way the wind is blowing? Does the suns position change if the wind changes while you climb to altitude? Using the sun as a reference point to determine wind direction is as good as flipping a coin, especially on days where the wind is constantly changing direction. You need to re think your method of determining wind direction before you hurt yourself. Back before the EPA was a reality, you could count on the plume from at least one chimney or smokestack being visible near a built-up area, which made real-time wind determination easy. For better or worse, those days are long gone. Using the sun as a directional reference provides a starting point, and it is of course not directly related to wind direction. It simply increases the odds that you are landing into the wind, which is a good thing. Pointing into the direction from which the wind was coming 10 minutes ago (if you're jumping Mullins' plane - there may be some that aren't as fast...) seems like a better idea than simply picking a direction and hoping that it's a good one. The contention that it is bad advice does not seem to be accompanied by a more effective field-expedient technique. If you know of a better way, please share it with us. Blue skies, Winsor

I have a mess of round reserves, but none of them are in CYPRES-equipped rigs. Putting a CYPRES in a Wonderhog is like putting a $50 saddle on a $5 horse. Blue skies, Winsor