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#41
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In article ,
Fred Mueller wrote: Now lets say you've arrived over the end of the field opposite the direction of landing and you're at 400 feet and 55 knots. You have been sweating the glide for miles and to land straight ahead into traffic you are now in a high energy situation to get down and stopped without rolling too far into the oncoming traffic. Going downwind at 400 ft at the departure end of the field? That's 200 ft higher and a 180 degree turn better off than the rope breaks that we routinely expect pre-solo pilots to cope with! -- Bruce | 41.1670S | \ spoken | -+- Hoult | 174.8263E | /\ here. | ----------O---------- |
#42
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JJ,
I am going to respond privately to you with specifics. I apologize to the group for 'teasing' you with a statement and then refusing to reveal the information that proves it. Larry "John Sinclair" wrote in message : There have actually been some with exactly the scenario that Kirk posited. Please provide us with the details of these finish cylinder accidents. I'm not aware of any. JJ |
#43
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01-- Zero One wrote:
I am going to respond privately to you with specifics. I apologize to the group for 'teasing' you with a statement and then refusing to reveal the information that proves it. Of course you will sanitize them and then let the heathen feast on them too, I suppose? Jack |
#44
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At 05:30 06 May 2005, Marc Ramsey wrote:
Andy Blackburn wrote: My point was I don't think it's a great idea to be so cavalier about low altitude spins. The 500' cylinder encourages an aggressive, ballistic pull up to reach the finish altitude for pilots on a marginal glide. The gate doesn't - you just land. The fact that someone got away with a spin at 400' is not a confidence-builder for me. Never mind, I keep forgetting to just stay out of this. I'd have a bit more respect for your position if y'all would quit trying to convince people its more dangerous to finish at 500 feet than at 50, but it really doesn't matter. *I* have margin for error at 500 feet, I have none at 50 or 100, tis adequate reason for me, clearly it isn't enough for you, 'nuf said. I do wish we could talk about this without the ad hominem commentary. I never said the you have more energy at 50 feet than 500'/1sm. I believe I pointed out long ago that 500' and 1sm at 60kts is the equivalent in energy of 50' over the airport and 100 kts for most modern sailplanes or +/-350' over the airport at best glide. It's a difference in energy to be sure. Everyone stipulated to that point long ago. The argument is about the more subtle points regarding decision making, heads-down piloting and traffic management. The cylindre proponents seem to deny ANY issues with the cyliner and come back to altitude as the ONLY safety factor on final glides and therefore conclude that the cylinder must be HANDS DOWN TOTALLY SAFE. Some of us would like to point out that it is more complex than that. I have never stated that the cylinder is less safe than the gate - rather that the biggest threat to safety is simplistic arguments that lead to flat assertions. 9B |
#45
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From an energy standpoint there is no problem at least not a low energy
problem, there is now a high energy problem. Imagine yourself at 400 feet on the downwind threshold. Where are you going to land on that runway? Now imagine a half dozen or more gliders coming at you landing from the opposite direction and some of those gliders intend to land long. If there are few or no other gliders in the pattern there is no problem. At a contest with 50-75 gliders all finishing within a very short period of time, the problem is very real. FM Bruce Hoult wrote: In article , Fred Mueller wrote: Now lets say you've arrived over the end of the field opposite the direction of landing and you're at 400 feet and 55 knots. You have been sweating the glide for miles and to land straight ahead into traffic you are now in a high energy situation to get down and stopped without rolling too far into the oncoming traffic. Going downwind at 400 ft at the departure end of the field? That's 200 ft higher and a 180 degree turn better off than the rope breaks that we routinely expect pre-solo pilots to cope with! |
#46
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#47
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Well Marc, you, at least, win points for a well-reasoned response. I
appreciate it. And we'll continue to disagree I suspect... The most important unanswered question in my book is the huge discrepency in speed we see at the cylinder wall and not at the finish line. One advantage of having been at this a few years is I recognize how much this smacks of the old start gate and the very real dangers is presented. I've seen far more close calls and accidents in the start gate than at the finish line, the result of the large differences in speeds among starters all trying to cross a line at or just below 5,000 feet agl. Go back and look at my model of the finish cylinder. http://users.adelphia.net/~cocallag Traffic is all arriving in a shallow arc at about the same altitude with as much as a 100 knot delta in speeds. Even more if gliders stop to thermal near the cylinder. This simply does not happen at the finish line. |
#48
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wrote: Marc, The finish line is a magnifying glass. The sins committed there are repeated throughout the soaring day. Only difference is, everyone sees and comments on them. The same and new errors will be made in the finish cylinder, but out of sight of the peanut gallery. This isn't safer; it just seems safer - a three-monkeys approach to safety. (And yes, while you have more altitude under you, you've also increased the likelihood and severity of collision.) In a previous post, I pointed out how little it costs in points to opt out of a 50-foot finish. Eight points max. On the other hand, the cylinder represents some known problems (head-down piloting) and unknown problems (traffic separation at the cylinder wall and procedures after the clock stops). Just because something "seems" safer, doesn't mean it is. And while we blunt skulls may seem unreasonable in our commitment to the status quo, some of us would rather deal with the risks we understand than journey off into the unknown. I and others have pointed out, in this and other threads, some of those variables. I've seen mixed results in how these questions have been addressed. One thing is certain... any finish is a high-density, high-risk environment, and my own experience is that I spend far too much of my time looking at instruments while approaching the cylinder for my own comfort (and for yours). When I call four miles, I want my head out of the cockpit 99% percent of the time. This simply isn't realistic with the cylinder. We need to fully understand where the benefit of lower density outweighs the effects of greater pilot distraction. A blue day AST or TAT raises the potential density of the finish, and thus the importance of heads up piloting. I could be converted. But it's clear the cylinder hasn't been adequately vetted. There's too large a penalty for rolling finishes, which means pilots will be trying all sorts of tricks to clip the bottom, flying at low speeds into high-speed, high-density traffic. And there's no standardization for pattern entry based on energy after entering the cylinder. For instance, at the Std Class Nats in Montague I didn't begin dumping water until after I pierced the finish cylinder. After finishing, I would pull up to 800 feet agl, open the dumps, and wander around the vicinity of the IP until I reached pattern altitude. After all, why should I take the performance penalty of dumping water if I have several minutes after the finish to lighten the glider before landing? Multiply this by 10, introduce variables in speed, altitude, wing loading, and pattern planning, and the IP becomes an increasingly dangerous environment. Where does this leave the guy who has difficulty judging whether he ought to light the burners or break off for a rolling finish? Or a pilot who cannot execute a brief 2-g pull and 180 degree turn to final? How will they deal with inserting themselves into a much more dynamic pattern with several other gliders, with lots of opportunity to raise the level of confusion? The cylinder has its uses, especially for open-ended MATs where racing is likely to take place in all four quadrants, but there's much homework yet to be done. Yes, you remove one highly visible maneuver - one the vast the majority of pilots can safely and successfully execute and introuduce a fistfull of unknowns that will affect everyone. Don't like the finish line? Can't judge energy? Can't execute the manuever? Don't light the burners. Why must I be exposed to what I believe is a potentially dangerous environment without choice because a handful of pilots are promulgating a "solution" that hasn't yet received due diligence (amply demonstrated by its proponents' inability to adequately address well-reasoned safety concerns)? I suppose the thing that irks me is not so much that this is a "lowest common denominator" solution, rather that it will have very little impact on safety. We'll improve things for a few pilots, yet expose all pilots to other safety concerns. And while we've netted a few hundred feet of cushion beneath those pilots who need it, that doesn't improve their ability to stay out of trouble elsewhere on course. It simply defers ignorance out of sight of the home drome. By the way, when was the last time you saw someone thermalling half a mile from the finish line? Or intentionally busting a gaggle at 140 knots? These aren't unreasonable scenarios and require only the same lack of judgement displayed by pilots who can't navigate a finish line. Remember the start gate? Thermalling wasn't allowed. Why? Doesn't the finish cylinder raise exactly the same concerns? So why wasn't this addressed? Why aren't YOU asking these questions? After all, your bent is toward making the sport safer, right? Safety is my primary concern. Which is to say, if I believed the cylinder was inherently safer, I'd be writing in equal volume in favor. But it's clearly not the cure-all some propose. At best, not yet. OC |
#49
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Traffic is all arriving in a shallow arc at about the same altitude with as much as a 100 knot delta in speeds. Even more if gliders stop to thermal near the cylinder. This simply does not happen at the finish line. Oh yeah? I was driving hard for the finish line at Ephrata, 1/2 mile out, 500 feet and 145 knots when I almost nailed a PW-5 at 500 feet doing an estimated 60 knots. All happened so fast I had no time to react. Luckily I went just over him. Another gooood reason to employ the finish cylinder, especially with sports class machines in the contest. JJ |
#50
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At 21:00 06 May 2005, John Sinclair wrote:
Oh yeah? I was driving hard for the finish line at Ephrata, 1/2 mile out, 500 feet and 145 knots when I almost nailed a PW-5 at 500 feet doing an estimated 60 knots. All happened so fast I had no time to react. Luckily I went just over him. Another gooood reason to employ the finish cylinder, especially with sports class machines in the contest. Wow! Got your final glide calculations that badly wrong? |
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