winsor

"I say, what's become of Chumley? Haven't seen him around the club." "I'm afraid he was kicked out for having sex with a sheep." "Oh, really? Ram or a ewe?" "Ewe, of course. Nothing queer about old Chumley!"

If you recognized the character, you would understand. If you don't get the joke, it's a waste trying to explain. Blue skies, Winsor

I have never met anyone who used the sunroof on a military aircraft and recalled the experience fondly. My standard questions are: 1) Where did you regain consciousness? 2) How long were you hospitalized? 3) Have you recovered fully yet? The answers I have received reinforce the idea that punching out is anything but a recreational activity. Blue skies, Winsor

I have the same Omega Speedmaster Professional I've had for the last 25 years (I don't think they make an Amateur model...). The one I'm wearing right now is the one Mike Mullins had in Vietnam. IIRC, he got his at about the same time as did Neal Armstrong for his trip to the moon. Though NASA now issues Timex Iron Man to their astronauts, the Omega is the ONLY watch worn on the moon. Any that aren't engraved with that trivia predate the first moon landing - the one I got from Mike has the original back, and my graduation present has the "first watch worn on the moon" back. The value of an expensive watch is similar to that of an expensive pen. A BIC might actually work better, but I have had the same Mont Blancs for many years and know exactly where they are at all times. The BIC I will "loan" to someone and walk away without a thought, but the overpriced one will not leave my sight. Similarly, I could get watches that do a better job of timekeeping for next to nothing, but they come and go. The overpriced dinosaurs will be around long after I'm gone because their cost warrants keeping them secure and in good repair. I don't want another overpriced watch, since I already have more than I need. Blue skies, Winsor

It is all patent nonsense. Some of the fairy tales are more poisonous than others, but fairy tales they are.

The reserve parachute was a reality before parachuting became a sport as such. Despite the continued use of single parachutes for intentional jumps by barnstormers and paratroopers, the TR Type chest-mounted reserve came into use in 1924. It was only in the post-WWII era that people used surplus equipment to parachute as a sport in any significant numbers. By then the use of a reserve was the norm for intentional jumps. In the early '70s the reserve migrated aft, finding a home atop the main. in the later '70s the ramair reserve became a reality, and by the end of the '80s it was the norm. About the only times a second parachute is not used are for very low altitude, such as combat airborne insertion and BASE, or emergency parachutes, where its duty is that of reserve from the outset - the aircraft serves as the main. Blue skies, Winsor

If you can use non-metallic, pilot flasks may do the trick. Check these out. For some reason the URL doesn't automatically bring them up. Put LEG-122 in the item# field and search. It works just fine for me that way. Three for $7.97 is not bad. Blue skies, Winsor

Rambocritic, eh? How can you possibly criticize Rambo? Without people like Rambo we could not possibly have achieved the resounding victory in Southeast Asia that we did. Or peace with honor or whatever. From the question you ask you might surmise that the whole of the script was cranked out by a 4-F wannabe whose knowledge of the military and parachute operations was and is nonexistent. These people make MILLIONS of dollars. They MUST have the inside scoop on the way things really work. You dare to question HOLLYWOOD? Well, if you're so smart, how come you're not rich? Anyhow, the short form of any analysis of any of the "Rambo" series (with the exception of the book "First Blood" by David Morell, which was okay) is that it is entirely nonsensical. It was written by Sylvester Stallone, who is a dyed in the wool civilian. The James Bond series has a more solid basis in fact than does the Rambo series. Ian Fleming was, indeed, an Admiral in Naval Intelligence, and created his title character as a goof - the exact opposite of what a spy really is. Instead of being sleazy people trying to get peoples nastly little secrets to leverage information, 007 was suave and sophisticated. Many of the devices provided originally by Q wound up in production for the masses, the Nikonos and office pagers being examples. Thus, your treatment of any questionable part of any "Rambo" story line should be simply "this is patently absurd because...." The only Vietnam film with a core of reality is "Full Metal Jacket." Michael Herr spent a year in the bush as a journalist - to include bunkered down at Khe Sanh during the siege - and captured much of the nature of the Marines he so admired in the film directed by Stanley Kubrick. "Platoon" shows the lack of perspective that comes with being a line grunt. Your view of the world is what you see out the back of a deuce and a half, and most would have to do a great deal of research to find out just what the hell they were actually doing. Oliver Stone drew the inaccurate conclusion that his presence on the battlefield provided him with a global comprehension of the conflict, but his film demonstrated convincingly that his understanding was both very local and flawed. When reviewing films about any conflict, do so with a great deal of skepticism. It is a rare piece of film that approaches a balanced and impartial treatment of a conflict, and most are little more than fantasy. Witness the "Rambo" series. Blue skies, Winsor

I was born in Boston, and the only professional sports organization I have ever followed is the Red Sox. The only time I really pay attention is when they have a shot at a pennant at least, and have tried to watch or listen to every World Series game in which they've been. This time I think they have a better shot at it than they did in years past, but only a fool would underestimate the Cardinals. I was in St. Louis a few weeks ago, and the mood could best be described as having reached fever pitch. Those guys are good, they're hungry, and they WANT to win. They are not going to roll over and play dead. Until the last pitch of the last game I will be holding my breath. The Sox have demonstrated that it is distinctly possible to come back from trailing 0-3 to win, so I won't be sure of the winner until it's over. Everyone I know who spent time in Boston in years past and spent the odd afternoon in the bleachers at Fenway is watching the series. So far the show has been nothing short of amazing. Blue skies, Winsor

I have put a number of jumps on a variety of Robo-Z canopies, and do not recall anything unusual about the openings. I'm sure you could pack it one way or another to get it to behave differently, but any pack job that would work with a Sabre will work with a Robo-Z AFAIK. The fact that someone was willing to put over 100 jumps on it is a pretty good indication that it didn't either incapacitate them or put them into CYPRES territory on a regular basis. Hell, I'd jump it. Blue skies, Winsor

Probably that you're not as neurotic as the "norm." I could never figure out the "hard to get" bit. Why would someon not seek someone who DOES trip her trigger? I figure if she's not interested in me, then why the hell should she waste both of our time? No means no, and it's binding. The "don't touch me there! I don't touch MYSELF there" response is a show-stopper. If that's in her repertoire, we aren't compatible. If sex isn't a very high priority, the relationship is doomed. Blue skies, Winsor

And sometimes dumb luck out weighs all three of those. I'd rather be lucky than good....

Since the mission of a sniper is surgical shot placement at extended distances, typically >600 metres, the ideal sniper rifle is one that is supremely accurate and uses a cartridge that is lethal at the intended range. Once those criteria are met, the "best" becomes, to a large extent, a matter of opinion. The 7.62x51mm (.308 Win.) cartridge is one of the most successful benchrest cartridges in existence. It has the advantage of placing a large percentage of the powder charge in the flash pattern of the primer, and thus has very uniform ignition characteristics. Absolutely brilliant bullets are available from a variety of manufacturers of .308" diameter, many of which are tailored specifically for

blowing in the same direction.... Good point. That's one problem with the short form. On a day with 40 knot uppers and 10 knots at opening altitude IN THE OPPOSITE DIRECTION, you have to increase your delay to maintain 1,000 feet of separation at opening altitude. The 90 knots true airspeed of the aircraft, minus the 50 knots difference between the winds at altitude and at opening altitude, gives 40 knots, or 67 feet per second. You now have to wait *15* seconds between each "go!" to get the same 1,000 feet between groups at opening altitude. Note here that reversing the direction of the 10 knot breeze altitude results in 50% more time being necessary to achieve the same separation. Reversal of wind direction with altitude is more common than people often suppose. I will often have a headwind at 2,500 feet, but a significant tailwind at 10,500 feet (or vice-versa). Blue skies, Winsor

Maybe I'm just not comprehending, but I don't think you have explained how to determine what "sufficient time between groups" is. Okay, the Cliff's Notes version is that you want groups far enough apart that they are not LIKELY to infringe upon each other's airspace. Here we're going to ignore the very real factor of groups sliding like a bastard in freefall, people breaking off early and tracking toward the DZ and so forth. If you factor those issues in, you'll want a separate pass per group. As an aside, we are concerned with what is happening in the air - the ground is an issue for spotting. If you look at the ability of a competent skydiver to track, assuming a 3,500 foot breakoff and 2,500 foot opening, you can expect the diameter of the group to approach 1,000 feet. The most important altitude to have full separation is opening altitude. This is where the radius of influence of a given group is at its maximum, and it is generally where the paths of the groups are at their most convergent. However, the most elusive parameter of interest is wind speed at opening altitude, so it is usually easiest to work around it. If it's not available, you can't waste too much time fretting. To start with a calm day calculation, figuring 90 knots true airspeed (150 feet per second) gives you a little over 6 seconds between groups for your 1,000 feet of separation all the way to the ground. On a day with 40 knot uppers and 10 knots at opening altitude, you have to increase your delay to maintain 1,000 feet of separation at opening altitude. The 90 knots true airspeed of the aircraft, minus the 30 knots difference between the winds at altitude and at opening altitude, gives 60 knots, or 100 feet per second. You now have to wait 10 seconds between each "go!" to get the same 1,000 feet between groups at opening altitude. A couple of caveats: 1) Vertical separation is NOT separation. Sometimes parachutes open much higher - or lower - than expected. 2) Sufficient is a judgment call. 1,000 feet between groups decreases the likelihood of one group intruding on the airspace of another, but does not guarantee it. If you have a handle on the variables, you can adjust accordingly. If you're following a 16-way out, you should assume they are going to break high and track like hell; give them PLENTY of time. A series of solos where nobody's tracking at breakoff can work with a couple of seconds between jumpers. Anyhow, the discussion of spotting and separation is sure to crop up on a regular basis, but the physics don't change. Once you understand what's involved, you need only pay attention and use your judgment. Blue skies, Winsor

It's a matter of opinion, basically. I, personally, prefer the standard Racer PUD, but have rigs with both BOC and PUD. In both cases you're reaching for a handle in the same place, and the both work just fine (in general). When the pullout was first introduced, it was going up against the bellyband-mounted throwout, so there were more significant differences between the two systems. The biggest drawback to the BOC, from where I sit, is the potential for an open container with the pilot chute still stowed. A high speed malfunction that requires the reserve pilot chute and freebag to clear the mess trailing behind you is not always survivable. Pilot chute extraction problems and pilot chute malfunctions (usually because of entanglement between hackey and bridle) seem less likely to occur with pullouts, as well. All things being equal, the comfort factor of the jumper is a big consideration. It's your life on the line, and if you have your procedures down pat with one, you may well stick with it. Hesitation kills, and if you are uncomfortable with a system - even if it's "better" - your actions may not be as swift and sure as with the system you trust. They have both been used successfully for millions of jumps, and it is largely a matter of personal preference. Blue skies, Winsor

Quote He entered a thread in the "Safety and TRAINING" forum rather with brisk words and when asked to elaborate, said it wasn't his problem or care. There's something wrong with that. If he doesn't care, why post?Quote The not caring part is regarding your analysis. To a great extent it really doesn't matter whether the reason why someone gets out with sufficient separation is physically valid - so long as they somehow provide for that separation. If you simply read numbers off a table and give the indicated exit count, that can work. You don't need to perform a detailed analysis every time you exit the airplane, and doing so won't eliminate rogue variables such as people tracking hell for leather at odd altitudes and pitching high, etc.. Thus, there is a difference between knowing HOW and knowing WHY. When people who have a pretty good handle on the how part of the deal conclude that they therefore understand why, I have a problem with it. Particularly when they're wrong. If someone gives a good count of 10 before jumping, I'm fine with that. That's the safety part of the deal. If they do it because the moon is in Aquarius and they saw a cat on top of a red car that day, I would rather not know. I am primarily concerned with the fact that they stay the hell away from me in the air. If someone wants to postulate an invalid model as the physical basis upon which they base their decision, I can't be bothered to hold their hand and lead them through it. It has been done to death on numerous occasions, and the information is available to anyone who takes the time to look. The "Safety and Training" part is, again, give sufficient time between groups to ensure adequate separation, and exit the airplane such that you can land somewhere safely. If you limit your focus to those issues, you should do okay. Blue skies, Winsor

It appeared that your argument was that separation only depended on winds at opening altitudes, and that uppers were irrelevant. Nope. Separation is a simple function of exit speed with regard to the airmass at a particular altitude. The minimum is typically the airmass at opening altitude (with an upwind jumprun) or at exit altitude (with a downwind jumprun). The speed of the uppers with regard to the ground is a consideration for spotting, but is irrelevant in and of itself for separation. These are related, yet very different, concepts. And something about 1000ft of separation. [But you kept it rather vague, and unexplained, with lots of wiggle room. I'll go see now if your notes are more clear.Quote Knock yourself out. If you can improve upon them, by all means do so. Blue skies, Winsor

So billvon and winsor don't seem to be in agreement here... at least the way I'm reading this. We're talking two different things here. Regarding the speed of the aircraft over the airmass at opening altitude we're in agreement. The other factor is TOT - time on target. If you have 7 groups getting out, and figure the minimum "safe" separation requires a 10 second delay, it takes 60 seconds to clear the plane. If, however, the length of time during which you can exit and make it back to the DZ without problems is 90 seconds (your time on target), you may well use the full 15 seconds between groups instead of the nominal 10 seconds. You take the extra time for the same reason as Fido - "because you can." There is no disagreement regarding the fundamentals of which I am aware. Blue skies, Winsor

The notes from my seminar at WFFC are here. Tammy turned it into HTML from Word, so I simply used it as is. No, I have often been impressed by how many people of my acquaintance have advanced degrees (MS & PhD) yet never got beyond the level of expertise at the basics that they achieved during Freshman year. They may be able to set up second-order partial differential equations just fine, but if faced with, say, rotational dynamics, through which they struggled to get a C, they would do well to show C level comprehension even now. I'm not trying very hard. From where I sit it's pretty obvious, and it is often most difficult to convey something that seems inherently apparent. The point being? That scenario has two parts - freeefall separation and window of opportunity. Freefall separation is based on the minimum relative speed of the aircraft with regard to any stratum of air throught which the jumpers pass. The extremes are generally found at either exit altitude or opening altitude, and the delay necessary to maintain separation at exit airspeed it the very least delay you should consider taking. Without wind direction reversal (more common than most think), the speed of the aircraft w.r.t. the air at opening altitude is the lowest pertinent value. With a tailwind, speed of the aircraft v.r.t. that air at exit altitude is the lowest. As the last part of my presentation describes, the window of opportunity on a pass is a function of speed over the ground. With a tailwind, your time on target can be short enough that you can get only one group out per pass without someone being hosed. With a headwind that reduces groundspeed to zero, you can put out one group after another all day long and maintain adequate separation at all times. I no longer teach Physics for a living. If you are an engineer, you should have the study tools to find the readily available resources and figure it out for yourself. It's pretty basic stuff. John Kallend is a professor, and actually has the patience to convey the fundamentals to a never-ending stream of neophytes. Bill von Novak is a skydiving instructor, engineer and pilot, and also has much more patience than do I. Ask them. Blue skies, Winsor

I took a lot of physics too. Did you pass?

The basic premise here is sufficient headwind to have zero groundspeed at exit. Think an AN-2 into 40 knot uppers. With no tracking or sliding, people (bellyfliers) are going down at 100 knots and horizontally at 40 knots - they are traveling along an incline. For 2,500 feet of vertical separation there is a 1,000 foot horizontal component. It's like being on an escalator. Everyone gets on at the same point, and off at the same point, but nobody is directly over anyone else. It's basic physics - freshman stuff (at least where I went to school). Blue skies, Winsor

The point you think you proved is entirely invalid. Everyone can open at precisely the same point and yet maintain 1,000 feet horizontal separation - if they do not open at the same time. Think about it. Blue skies, Winsor

Not hardly. With sufficient uppers, everyone can exit at one over the ground and open at another point over the ground - and still have plenty of horizontal separation! How's that, you ask? Simple. Remember those winds we mentioned before? They are busily blowing the first group downwind long before the next group gets there. It's only when you try to occupy the same place at the same TIME that things get dicey. If you throw in the extra dimension of time, you get a different picture. No, it's more like why a dog licks his balls - because he can. If you have the opportunity to take more time between groups and still get back, by all means use it. About the only factor that dictates a longer delay with more headwind is the difference between winds at exit altitude and winds at opening altitude. That's where the groundspeed plus winds at opening altitude (minus if the directions are opposite) comes in. No. Blue skies, Winsor

For the record, no, we are not in agreement. Winds aloft, in and of themselves, have nothing in particular to do with separation. If you want to consider separation at opening altitude, the relevant parameter is airspeed with regard to winds at opening altitude. Groundspeed (like from the GPS) plus the magnitude of winds at opening altitude (the headwind component, at least - it's actually vector subtraction) gives you this value. Rather than rehash the whole thing again, or have you spend a semester studying Kinematics, you would do well to simply do a search on the subject on DZ.com. Be advised that many people put forth physical models therein that are complete hogwash. A good rule of thumb is that if they disagree with John Kallend, they're wrong (I'm serious). Blue skies, Winsor