alan

I can see Spary's point too. What he doesn't seem to understand is that when he flatly stated: "The chest strap is not designed to be load bearing during deployment." he contradicted himself since he had already previously stated:"With chest rings it is easy to pull the MLW out of alignment and transfer the opening loads to the chest strap which is not designed to take that kind of load." I added the bold font. The chest strap IS designed to be loaded. IF it is OVELOADED it may fail. An improperly adjusted harnes COULD overload it. During a normal face to earth deployment, the weight of the jumpers upper body is transferred in part to the chest strap. That IS loading it! And if Sparky was as familiar with PPM Vol ll page 335 as he has suggested I should be he would know that Poynter never mentions a chest strap speciffically but does say "The purpose of the parachute harness is to transmit the opening forces to the wearer in such a way as to preclude injury and to support the wearer during descent." He does not exclude the chest strap and I would argue that the chest strap is part of the TSO'd harness container system. Is it not? Poynter goes on to state: 5. The harness must securely retain the body. 10. The harness will not slip off the shoulders. 11. The wearer will not fall out the back of the harness even when the knees are drawn up to the chest. The only specific mention of the chest strap refers only to the fit on women. The most important and relevant point that Poynter makes (ha! ha! I said point that Poytner makes ha!ha!) is: 20. Angle the straps in the direction they will be loaded so the anchoring stitching will be evenly loaded. That is Spark'y point, I believe, based on his diagram. My point is it is loaded. Sparky should have just stuck to his original statement that it is not designed to take "that kind of a load." Sure the purpose is to keep the wearer from falling out.....what do the leg straps do? Ummm, keep the wearer from falling out. You and Sparky and JP and Jerry gonna tell me that the leg straps aren't load bearing either? Sparky has recently stated that the main lift webs are load bearing that is why they are called "main lft webs." All that means is they carry the main load, not all of it. Hell even the back straps are load bearing during deployment! Yes! The back straps. Sparky, if you are reading this, go to page 243 of PPM Vol 11 and read the second paragraph. You chide me about what Poynter has to say about harness design, here is what Poynter says: " In fact, only about 15% of the opening force is taken in by the back straps (my emphasis). Well if the back straps take only 15% of the load I wonder what the chest strap takes when a load is applied directly to it, as in your chest during the deployment sequence. So, what I understand is that Sparky seemed to have it right and then contradicted himelf and decided to get into a pissing match with me rather than admit he misspoke when he said: "The chest strap is not designed to be load bearing during deployment." As far as the KBAR comment goes, you'd feel pretty bad after Sparky was shot with his own gun. And Sparky, while you are reviewing the section in PPM about design, check out the part that distinguishes deployment from inflation. Based your comments in a different thread, you seem to have missed that part. I know you shut the door on this, so I figured I address my comments to you here, you'll read 'em. alan

Should have said it better Should have. Could have implies a certain capacity. alan

We still are. Sparky implied that a con of chest rings is that they are subject to improper adjustment and by overtightening, during deployment the load is transferred from the MLW to the chest strap, which he maintains is not supposed to be load bearing. That is a dangerous statment to make. Someone believing him may decide not to invest in a fully articulated harness for the wrong reason........or may be complacent about their chest strap......or follow the advice of some rigger that says it is OK to use a rubber band instead of a functional and properly routed chest strap. What say you, oh keeper of the peace, is the chest strap load bearing during deployment or not? Oh, and rings can make it difficult to sneak up on people while wearing the rig, they can squeak when you walk or even move. alan

I have read it. In my opinion, it supports the notion that the chest strap is loaded during deployment. alan

I didn't say Rob was wrong, I said he displayed a rather condescending attitude. I wonder how he would have done routing those cables without the benefit of the instructions or someone at RI to show him how. alan

As long as this thread got bumped, I'll add a few comments about freefall time. One of the primary thrills of a balloon jump is the first 10 to 15 seconds of freefall. You go from quiet, still air to the sound of terminal velocity. Enjoy the thrill, don't waste it by getting excited and dumping right away. Look up at the balloon as it seems to race away from you. Look at the ground and experience some ground rush. Yup. Many jumpers from the AFF/ISP era have very little experience getting out at altitudes of 3500' or less. For safety reasons, most of todays jumpers prefer to be open by 3000'. Quite often when jumping a balloon it is not unusual to exit at 3000', even though altitudes of 5000' are very common. Lets say you get out at 3500' and take a nice 10 sec delay to ejoy the whole experience. That has you dumping at 2500', which with many of the newer and more popular canopies today, should have you in the saddle with brakes released by 1700'........which is below the decision altiutude for many jumpers, especially with a "B" license. For a regular skydiver with no base experience, this may get a little scary. Just be current and know what to do. If you have to cut away, get it done because you can burn through several hundred feet trying to fix it, then making the decision to cutaway, and then performing the actual cutaway. If you are in the saddle at 1700' from a 3500 exit after dumping at 2500' it is fairly normal. A mal discovered at 1700' can get you down to 1200' before you are under a functioning reserve. That doesn't leave much time for finding a good spot to land in an unfamiliar area. Geez, take a 15 sec delay on that same jump and you're at 200' before getting a functioning reserve. If you pilot offers 5000' for altitude, that is great, take it! Have a pretty good idea of what your intended exit altitude should be. Make sure it is high enough for you to enjoy the thrill of doing what ever you want for the first 10 to 15 secs and still allow you to open at an altitude that is comfortable for you, as skydiver using a skydiving rig. If you are a BASE jumper using BASE equiment, adjust your exit as you are comfortable with. Make sure you are comfortable with off field land on the canopy you are using. Landing in 3' high unmowed hay on light/no wind day can be tricky on a sub 100 canopy at a 2.4 W/L. Don't even think about soy beans! Try to experience at least one jump during each of the four seasons. Each offers its' own kind of beauty and challenges. Fun fun fun. alan

Already saying it in the Harness question thread. Robs the one saying the average skydiver isn't bright enough to route cutaway cables in a soft housing. I know I can, so if you can, then that would put us in either the above or below average groups.....pick the group you want, I'll take the other. Just don't get pissed at me because Rob thinks he's brighter than the average skydiver. alan

So, please explain to me what subtle difference there is between containment and bearing? How can a chest strap contain a body without carrying a load? Magic? A cardboard box is a container, yet they are rated for load bearing capacity. The reason the rest of the rig is not made of Ty 17 and 500# hardware is that they are built to the design load. The MLW needs to carry more load than the chest strap, so it is designed accordingly. Risers (Ty 17, BTW)are load bearing, yet are not designed or built the same as the MLW or leg straps, etc. BTW,your are right about one thing. Forgetting for (sic) fasten it does not make it load bearing. Forgetting to fasten it makes it non-load bearing, hence the young woman plunged to her death. Had she fastened it, it most likely would have bore enough load to have kept her in the harness. alan

Rather condescending attitude displayed here. Must be referring to Sparky, he thinks the chest strap isn't load bearing during deployment. Hee! Hee! My ass. alan

Tell that to the family and friends of the young woman that fell out of her harness during deployment after forgetting to fasten her chest strap. There is such a thing as load distribution. There is a reason for having a chest strap and it is load bearing. alan

I've been jumping with stitched risers on my 89 VX for five years at about 2.4 w/l and saw Andy Anderson using them in Coolidge back in 2000 as well. The change in trim angle is very subtle and the change in drag can be offset simply by what you are wearing on a given jump. With the canopy you are currently jumping at your w/l and swooping experience, I would not expect you to notice any real difference. There is the placebo effect though, if a doctor tells you it will make a difference, and you believe it will, then you may perceive one or become more in tune with what you are doing and actually experience some change. At any point, I would place more emphasis on piloting skills than stitched risers. If you have them, fine, they won't hurt a thing. I did mine with size "E" nylon and have had no wear or failure issues.....no ill effects at all except bulk on the sides of the rig. They make the pack look a little bulky in places, but then so do the stiffeners on the dive loops. Bottom line is it will be a non-issue for you. Have fun. alan

Don't take advice from an internet rigger suggesting that you make an unauthorized modification to your TSO'd reserve system. Contact the manufacturer yourself or have a trusted rigger near your DZ do it. If the rigger that packed the rig the way it currently is, has seen the problem and the fit and hasn't offered to fix it, I'd be leary of that rigger. alan

Before it was watch how fast you are going. Now its watch your rate of descent. You don't really seem to have a clue, yet you post advice here. I guess that's one way to learn, post poor or wrong "information" then hope someone corrects it. Tell me which is giving you a better glide, 15 ft/sec rate of descent or 10 ft/sec rate of descent? Hmmmm......10ft/sec. I'm at 3000' descending at 10ft/sec in fairly high head winds, say about 20 mph from 3000' to the surface. I use brakes, risers, what ever to stay aloft for 300 sec or 5 min. My air speed in this configuration is also about 20 mph. How far do I glide? Zero. Notta. Nothing. Zip. Zilch. I descend straight down, even tough I'm in the air for 5 min from 3000' and only coming down at 10 measly feet per second. Now......I'm descending 33% faster at 15ft/sec from 3000' with 20 mph head winds from 3000' to the surface. Again I use brakes, risers, whatever to stay aloft for 200 sec or 3 min 33 sec. My air speed in this configuration is faster at about 25 mph and with the 20 mph headwind speed, I now have a ground speed of at the very minimum of 5 mph. Now my glide, even with the faster rate of descent is .29' Gee, a 33% increase in rate of descent and virtually no change in glide. Try again...........I'm descending at 15ft/sec from 3000' with 20 mph tail winds from 3000' to the surface. Again I use brakes, risers, whatever to stay aloft for 200 sec or 3 min 33 sec. My air speed in this configuration is faster at about 25 mph and coupled with the faster 20 mph headwind speed, I now have a ground speed of at the very minimum of 45 mph. Now my glide, even with the faster rate of descent is about 2.7 miles. Butttt....I'm descending at 10ft/sec from 3000' with 10 mph tail winds from 3000' to the surface. Again I use brakes, risers, whatever to stay aloft for 300 sec or 5 min. My air speed in this configuration is slower at about 20 mph and coupled with the 10 mph tail wind speed, I now have a ground speed of at the very minimum of 30 mph. Now my glide, even with the faster rate of descent is about 1.8 miles. Well gee, I guess rate of descent all by itself is pretty useless. You have to be aware of your airspeed, the windspeed, your ground speed , and rate of descent to even begin to figure this out. Then you need to know your canopy, what various brake or riser inputs will produce a known airspeed and descent rate. alan

This results in an increased potential for a collision, especially at a busier DZ or boogie. It is far safer to be more precise in your pattern altitudes and use brakes for adjustment rather than S turns. Unfortunately, many students learn to do this while on radio because it seems easier for the person on the ground and there are usually very few, if any, other canopies in the area while a student is in the pattern. It is important to learn to use S turns, as well as when and where they are appropriate. S turns are great for collision avoidance, and may often need to be done "flat" in that circumstance. "Gentle" S turns on downwind and base can help you set up better for final and more importantly give you a better view for any nearby traffic. S turns are cool up high for the same reason, get a better view of traffic before making a more radical turn or spiralling. This is not a comprehensive discussion on the topic, but you get the idea. There are times that S turns aren't the safest choice and we can use fixed wing aircraft as a model like we do for our standard patterns. For example, while it may not be a perfect analogy, But when a jump aircraft turns on final, they don't adjust their glide path with S turns, but instead use throttle and pitch. Minor adjustments are made to the heading to stay centered over the runway. A canopy pilot can use brakes to adjust the glide path and make small heading adjustments to stay on the wind line. Just think, 12 or 13 other canopies may all be landing in the same area at about the same time after an Otter load. These canopies can vary greatly in speed and performance and will have pilots of varying skill levels. This may spread them out a little and the load type and exit spacing may help do this as well. But I have been around long enough to know that it is not uncommon for several canopies to be vying for the same airspace on final. At this point if one pilot does something unpredictable or unanticipated by another pilot, a collision can result. S turns are simply not as predictable as a nice, straight approach on final with only minor heading adjustments. So, what about the swoopers doing big 270's and 360's on to final? They usually have a separate area for this and again are usually more experienced pilots with the skill and experience to know where and when to expect other canopies and make good decisions for setting up their approaches. Also, they usually are skilled enough so that the approaches they set up are very predictable and finish with a nice straight final coming out of the recovery arc. The key here is being predictable. You seem to have that idea because you "like to fly part or all of my box pattern (three 90 turns, more or less;". It is just a thing that falls through the cracks at many DZs. Students get accustomed to doing S turns while on radio and then just continue doing them as they progress and the more experienced pilots let it slide until it becomes an issue. Over time though, many of the "experienced" pilots are ones that fell through the crack and then virtually no one knows any better. Sorry for the big speech, I just thought that if I was going to comment on the S turn on final thing, that I should at least explain myself. I won't take the time to look it up, but there may even be a recommendation about this in the SIM. You may have figured this out by now, but I'll say it anyway. This post isn't a direct criticism aimed at only you, but just something thrown out there for all of us to think about. alan

Well, first you claim that adding the backstrap is no more a modification than adding a hook knife or altimeter. Then when questioned about load bearing and transfer of loads you admit that an alti and knife do not do that, but try to muddy things up by adding "unless a line gets hung up on them". That is true but not part of the criteria for determining alterations or modifications. Now you simply claim not to see how the TSO would be invalidated. Fair enough, because I don't believe there is a clear answer in the FARs. You can however refer to AC 105-2C for "guidance" and it should be followed, even though it is not "law". At least, that is what they say. 1.24.2 Par. 8 Parachute alterations I won't type it all out here as it is easily accessed in PPM page 30. It is not very definitive but examples mentioned include installation of reinforcement tape or fittings, alterations of the harness such as changing the size, removal of a manufacturer-installed part ....... Reading on though it is apparent that the FAA expects a person qualified to alter a TSO'd sytem to contact their local FSDO inspector to discuss the proposed alteration. I was always taught that if there was any doubt, call the manufacturer. Seems reasonable. It may even be the first question the FSDO inspector would ask; "What does the manufacturer say?" Par. 10 on page 31 of PPM may also add some insight. It discusses "Extra equipment". "Attachment of an instruement panel, knife sheath, or other material to the exterior of the parachute assembly is not considered an alteration." Clearly it describes the non-load bearing or transfering items such as knife and altimeter "unless a line gets hung up on them" that you compared your strap to. Par. 10 goes on to state: "If any extra equipment is attached to a harness, care should be taken not to impair the functional design of the system." Clearly not a smoking gun one way or the other and obviously open to interpretation by a FSDO inspector, as is so true of most of the FARs. That is my point. If there is any doubt, the rigger should at the very least consult the manufacturer. A seemingly minor alteration, that on the surface doesn't appear to affect the functional design of the system mjay have hidden and unintended consequences. An example that comes to mind is a few years back someone converted a rig from ROL to BOC and in the process, cut the velcro off the harness to tidy things up. Unfortunately, on that particular system, the velco was attched with the harness stitching and the harness failed. Then there was the unfortunate incident with Patrick D. Maybe now you can see how the TSO may be invalidated. Maybe, just maybe, your master riggers and Sparky were just a little too sure of themselves and made an error in judgement. At the very minimum, I believe your are sending a very dangerous meassage to the readers of this forum. They read your comments and think, hey she knows her stuff, that must be a good idea and they run out and imitate you. Pretty soon, any "good idea" just about anyone has is cause to ask your rigger to make untested changes. I'm a rigger and I've done the try to fall out of it tests. I don't have anything against making things safer, just try to do it in the right way. If you and your riggers truly believe that making a change to the load distribution of your TSO'd harness does not impair the functional design of the system (without any standard for the type of webbing or stitch pattern), then all is well, but think about how readers of this forum may interpret your actions before advocating them to such a large audience. alan

Mathematically what you descibe is just incredible. There are thousands of FT-50s out in the field and have been for years, most of which have performed as designed. To have 6 fail at random all on one team exceeds a mind boggling statistical probability. I'm curious if you contacted the manufacturer, and if so, what they had to say? alan

Does an altimeter or hook knife connect two pieces of load bearing webbing, carry any load from the wearer, or transfer any loads? alan

The harness is part of the TSO'd system. Would this be considered a modification to that system? alan

Good stuff. Does that same site offer any insights as to the proper procedure for flying in turbulent or gusty conditions near the ground in preparation to land, say like on final approach? Doesn't it recommend going _faster_ than the normal approach speed? alan

"people" ??? That is being rather kind. At my DZ they are commonly referred to as fools, newbies, or any combination thereof. alan

The canopies that are on the ground and safely stored away for a better day. If you sift through the plethora of pointless crap that is posted in this thread, you will find a few genuine pearls. Educate yourself, understand the basic theory of flight and aerodynamics. You will then know how to avoid bad situations and on the occassions when you are simply thrust into them, you will better understand how to correctly assess and respond to a given situation. alan

That analogy is so poor it begs me to question the validity of anything you have posted. That is a pitty because I thought you were doing pretty well with the rock in the water part. An airlocked canopy is nothing at all like a metal boat in comparison to a rubber raft. A much better comparison would have been to a compartmentalized raft. Ahhh.....you have won me over again. Now I wonder if you are a parrot that got lucky or a thinker with a lapse in judgement. alan

Twardo, I thought you said you would retire that canopy. Be kinda funny if someone cut it away so it lands in the pyro area just before the Warbirds perform. alan

Hahahaha! So true, yet so confusing. Police officer: Why did you run that stop sign back there? Physicist: Because the more I accelerated the harder it became to stop. Police officer: Try decelereating the next time. Physicist: But that is exactly what I did, a layman such as yourself would never understand that they are one in the same. As a physicist I only use the term acceleration because it is too confusing to define the difference. Police officer: Would you please step out of the car sir. It is not because they are weird and picky, it is just because they are wierd. Uhhh...what are the reat of us supposed to use, you know the one's that aren't physicists. Can we still decelerate? Just havin' a little fun. alan

Agreed, as I pretty much said the same thing in different words in my first post in this thread. Agreed again! With a small qualifier, it does appear to accelerate away from the jumper, but we need to remember the jumper is moving as well so it does not seem logical to only consider the perspective of measuring from the jumper without taking into condideration the Earth. We cannot discount the forces that causes the change in velocity and it's source, gravity and drag. This one is a little trickier. Measured realtive to Earth it decellerates as it comes out of the pack tray, at a greater rate than the jumper accelerates during that brief period, due to a higher coefficient of drag than the typical jumper. Quite simply, it is going slower than when it was still on the jumpers back. Then I would guess there is a brief period of acceleration at line stretch and as the canopy comes out of the bag. Once it is free of the canopy there are some minor variations but it accelerates briefly until it reaches a stable terminal velocity that can be influenced by changing atmospheric conditions and changes in drag induced by a changing decent configuration, it is twisting and turn as it comes down. I think acceleration and decelereation tend to be the same thing in a void where there exist only two objects. Then you only need one to be moving but it works the same if both are. The measurent is from either object and as long as the distance between the two is changing at a varying rate, they are accelerating /decelerating away from each other and the terms are interchageable. If you introduce a third element then it changes. In this case it is the Earth. And even though it is moving itself, it profides a constant of relativity for the other two elements. Just mull it over, even if I have it all wrong, there is no real harm in that. alan