hackish

It is the physics I was trying to decode. RiggerRob and others suggested some books covering rigging and canopy flight so maybe those will be able to fill in some of the technical details. My concern in this thread dealt with whether I had "done it right" especially if the physics (which I do not yet fully understand) say otherwise. -Michael

I wear contacts. I picked up some soares from paragear. I love them. Some of the more experienced at the DZ have told me that they start leaving black marks on your face when they wear out but for $18 I'll just get another set at that point. My instructor insisted on me having clear lenses so check before you buy. -Michael

I always like to hear more than one opinion. Now I'm anxiously awaiting the theory books I ordered from Paragear and the weekend so I can try this stuff out again. Since my instructor is more than willing to sign me off he's obviously satisfied that the tasks were complete but I'm considering this a learning exercise. -Michael

Well I just honked on the front riser and it turned around. I sometimes do this if there is a tandem coming down after me so I've landed and am well clear of that. However, someone with a respectable amount of experience pointed out that the physics of pulling a front riser on a larger canopy make it impossible. For that reason I'm exploring the possibility. He also pointed out that a body builder friend wasn't strong enough. If he isn't then I am probably not! I'm flying a sabre 210 as I got my solo license about 10 jumps ago. Body weight is 180 so my exit weight should put me around 1:1. -Michael

Yeah, sorry I backwards wrote it. I'm trying to base my numbers off the altitrack. That gives me the opening altitude but it's difficult to tell exactly what altitude the PC was pitched at. I'll try to watch that a little closer. -Michael

I'm sure the post about removing the slider and mine were both jokes. Learning the details of what can be done to speed and slow openings is the exact point of this thread even though not many details have been offered yet. -Michael

Haha. How about getting a 1/2 mesh one from a base rig? Let's not and say we did :P -Michael

Spent the drive home considering a post I read about the force vectors of landing and flare some of it commented on by Brian Germain. Just trying to work out the physics of what happens and if it's possible on the gear a student would fly... Turns out I'm wrong on the CSPA requirements as they ask for: Under canopy, demonstrated a 360 front riser spiral (above 2000 ft) So in pondering things I've got a bit of an incomplete picture of what happens when you pull down on a front riser. I assume on a 9 cell configuration the front riser is attached to the A and B lines of 4 1/2 of the cells? In full glide I assume they're going to be supporting about 1/4 of your weight which you need the strength to "lift". So if you pull down on the front riser you're not only going to change the angle of attack for one side of the canopy but your weight may pivot toward the front riser you're pulling increasing the angle of attack on the other side because the opposite force is applied to the C&D lines on that side... I think this is going to be a more consistent or "aggressive" change on a more elliptical canopy and more abrupt on one with a different aspect ratio (smaller from front to back). I assume this is why the sport canopies respond faster. Gets complicated really fast. I'm assuming here that an elliptical canopy is shaped such that the length of the lines are equal rather than something that flies "flat" above your head. If the canopy is tapered it should even be more aggressive as the AOA should change more toward the outsides... So that covers how I understand the canopy will then begin the spiral turn but as the turn goes there will be centrifugal force applied from your mass to the lines plus the riser you're holding down. This may as DSE pointed out via PM overcome your strength. I wonder if the force isn't applied more to the unpulled toggles as in theory the changed angle of attack should mean less lift on the corner of the canopy you're pulling the riser on? If you put on the brakes as monkycndo says then your inertia should swing you forward a bit causing more slack in the front risers and thus making it easier to pull down but will that make you do the front spiral better? I'm not convinced because I assume the spiral comes from the deformation of the wing - something not yet accomplished by taking up the slack of swinging your mass forward from applying brakes. Ok I worked a 16h shift and now my head hurts... Anyone have comments on the physics here? -Michael

From another thread someone pointed out via PM that it's nearly impossible under a large canopy to successfully perform a 180 degree front riser turn. I thought for sure that I had done it and satisfied the requirement for the CSPA "A". Upon further discussion it would appear that on a 1:1 wing-loading it should be nearly impossible for me to perform this task because of the G-forces involved. So this weekend I'm going to grill the instructor for more details and try to re-do that portion of the requirements just to see if I am able to satisfy it. This all begs the question of why the license would ask you to do a task that should be more or less physically impossible? Or are some people working on their "A" license flying smaller faster sport canopies? At my DZ the student gear is in the 280 range PD280/Parafab 284/Tutor 9 cell). At the DZ where I did my FJC they flew Mantas which were also around 280ish. -Michael

I'm not absolutely certain on the amount of time it took to open each time. Once was 1200' I'm about 80% certain about that. At about 5k I waved off, tracked away (not that I can track that well yet), then checked the altimeter, checked the airspace again and deployed. Was open by 2800. Fairly sure I tossed at or about 4000. If the weather is good this weekend I'll pay more attention... People are already calling me the airplane whore 'cause I got 5 jumps in last weekend (there was only one TM). -Michael

Wish I could have gotten up on that load. I'd love to see how my amateur tracking skills compare to you guys. Best I've gotten was like 104mph using TAS. I need more jumps first and I'm using all I can to finish the RW portion of my "A". For the GPS idea I've ordered a garmin SDK and with a small micro and MAP sensor I believe I may be able to log horizontal and vertical speed. I've only got a big honkin old school GPS that wouldn't work. -Michael

I am fairly certain it is not a sabre2 - it's the one with the twin steering/brake lines (which I find a little more challenging to deal with). A scary long time to deflate was me watching it in that square configuration for a bit. Then going "Here slider slider slider.... come on boy... you can do it..." Finally the slider came down. Maybe I should just stop talking to it or someone will want to throw me in the funny farm. :) -Michael

I understand that PD recommends a camera type packjob on the sabre 210. The last pack I did was like this and it was a very nice soft opening. The downside is that it took a scary long time to inflate. I'm in the habit of watching the deployment and there didn't seem to be any trouble with the PC. It is fairly new and didn't seem to have any trouble pulling the bag up and open. From there that square mess of flapping stuff seemed to just sit there for a long time before the slider started to descend. Next jump the packer did and not knowing about the recommended rolling of the inner and outer 4 cells he packed it normally. It did not seem to make a difference but it did open with some linetwists. It was a stable toss so maybe it was just unrelated bad luck. Can anyone make a suggestion as to how this thing can open a little quicker without having a banger? I am deploying stable at terminal. I usually pull at 4k and it's open at 2800 to 3k. The canopy is a relatively new rental unit and the nylon seems to be fairly close to a new zp canopy while packing. Maybe this is just par for the course? I'm just a little concerned if I do a H&P at 3k. -Michael

While I have no experience in seeing an AAD fire I do have a suggestion. I know the vigils store the descent data from the last 10 flights. Why not regularly download this data and determine how far from the limit each flight has been. I assume the manufacturers did some extensive testing to determine the proper cutoff on descent rate. One other point I learned from a technical discussion with my rigger is the importance of leaving the brakes set on a reserve should it come out along with the main. This was not taught in my FJC and I'm not sure why... Any comments on that? -Michael

Sorry I should have stated that I'm talking about flat turns on final. Reason I was curious was to see how the sabre 210 compared with the PD280 and the tutor 9-cell (280 maybe?). The PD flies a million times nicer than the tutor but I can't really put a finger on why. The sabre runs a lot quicker but the glide ratio seems about the same or even better. One other thing is that while the turn itself does not appear to be losing much altitude the resumption of full flight after that does. Perhaps the sink rate during the turn is less than the glide slope? Carving definitely eats up the altitude. For my "A" they required front riser turns above 2000' and although I've been doing these for some time on the slower student canopies a complete 180 (hook turn maybe) loses exactly 50% the altitude of the sabre. A GPS would be good too because it's sometimes hard to match the data up with all the different things I do from 4k to 0. Sorry to get so far off topic. I'll maintain what I originally said that the OP needs to talk to his instructor. For me smooth turns at altitudes lower than his 300' have worked very well and my instructors have never had a problem with it. What worked for me some here call "luck" and may not work for any other students. -Michael

I've tried datalogging my turns but haven't been able to see a huge increase in rate of descent while turning. I wish I had a small enough GPS to log the actual forward rate of speed. Hard to tell how fast you're actually moving relative to the ground. The gust of wind was scary because it caught me at about a 45 degree angle and made me swing backward a fair bit. I was on final and at about 15'. Not fun when you're preparing to touch down and suddenly you go from forward flight to swinging backwards. Still landed it OK. Instructor said I was lucky it didn't deflate the chute. After that jumping was over for the day. -Michael

I generally complete my last turn to final at about 100' of altitude - a little higher with the sabre since it flies quicker. By the time the landing flare comes I've already had a good 5-10 seconds at full flight. Sometimes the turn ends as low as 50' but I still have lots of time to get back up to full flight before landing. Twice now I've had to make deviations at the last second. Just yesterday I got hit by a gust of wind as I was flaring to land. The correction just consisted of squeezing a little more on one toggle to correct - a flare turn about 45 degrees and still a good stand-up landing. The other time was when an excited wuffo ran directly across my path and it was just a slight flare turn so I didn't plow into them. I don't know if this is all called luck. My instructors have always said that I can be more aggressive under canopy as I'm "very conservative". As long as they don't have anything critical to say I'll just keep on doing it. -Michael

No, we're not. We're basing it on seeing student jumpers flying mantas, navigators and the likes break limbs or die because someone told them they can turn low. We're also basing it on people having been told that "giving gentle inputs and especially on a low wind day I'm able to turn the student canopy to pretty much wherever I want at reasonably low altitudes" is reasonable and end up cutting accross a pattern and creating colisions on landing. The original question was about making a turn into the wind at a low altitude. It had nothing to do with landing patterns or traffic - a completely different topic and one I'm trying to address. If you re-read what I've said it's not advocating anything but making sure the answers are appropriate for the situation and what the student is capable of. I'm not saying "go ahead and rip it around at 50'" but I have had to make low adjustments to avoid hazards and have been able to complete them safely. -Michael

So it might have looked like one of the rigs in the attached photos. Yes it looked like the big green one second to the end. I looked at their "release" system and there is no way I'd consider jumping it either. The reserve procedure consisted of unzipping the belly mounted reserve and throwing it out to the wind. YIKES! I think this one falls into the sweet find category. Although the owner hadn't jumped for 20 years he did take good care of the equipment airing and repacking it every couple of years. The guy who wants to jump it is known as "crazy larry". Although the nickname is funny with his experience I don't think he'd jump something unsafe. Certainly the riggers inspecting it have a reputation for being extra cautious. I'm hoping he can do the jump and I can get photos because it's a really cool looking PC chute. I won't spoil it too much because I'm sure he'll try to get it published. -Michael

I'm talking about giving the person advice appropriate to their skill level. By giving gentle inputs and especially on a low wind day I'm able to turn the student canopy to pretty much wherever I want at reasonably low altitudes. I've since moved to a sabre 210 which I've found more sensitive - again advice appropriate to the skill level. I have successfully made low corrections that some would classify as a "late turn" and still had a nice stand-up landing. Fall winds here tend to be fairly gusty. Unfortunately most of the hard and fast rules more experienced jumpers tend to give are based on the canopies they fly. Of course you can't bury the toggles on a sporty canopy but even trying to make a student rig rise on a flare has proved difficult (uphill landing). For those giving advice to students I'd encourage them to occasionally hop on a student rig. Going back to them even from a tame sport canopy like the sabre 210 feels like I'm flying the goodyear blimp. At least 1/2 of my jumps were 25m from the target but some students have trouble getting it into the same field. Again advice has to be tailored to what the person can do. Finally, I don't think porpoise's comments are fair. Maybe my solo license isn't good in your country but it does not mean that I don't have anything valuable to add. I'm sure someone with 2000 jumps could make fun of your 120. I wonder how many people looking down their noses can say that they've recently flown the type of equipment the advice is being asked of? -Michael

Back on topic if we can. There is considerable grey area around a late turn. I'm sure the OP's instructor can give good advice that would be appropriate to the skill level of the person asking the question. I personally have found even from my first jump that student rigs respond very well to small adjustments. If you're continually tuning your flight path so you stay on heading to achieve the desired landing point then I can't see it causing any big problems. Having said that I wouldn't suggest doing a 180 degree turn within 50' of the ground. As you progress and begin moving toward sport canopies they become more responsive and sensitive to inputs and symmetry during the flare. So some equipment and some experience levels low turns are definitely a big no-no. -Michael

I would strongly suggest talking the DZ before doing this. Them accepting your AFF course is going to be up to their discression. If you're like me you won't be perfect after the number of jumps required for the AFF so I suspect the new DZ may require you to do some more training. It may help you to skip a lot of steps but still... -Michael

So I did some thinking and asked the local riggers about this issue. At least 2 of them stated that when doing a reserve the entire thing is hand inspected and in 3 different places the material is strength tested at about 75% of the manufacturer's rating. I know at least one of them is known for refusing repacks because they failed an acidity test. So if you hand inspect the reserve, verify all the lines, connections etc. If you test and properly inspect the nylon and everything passes then as some have said what is the harm in using this older equipment? From my limited point of view I can see that perhaps the design may have been supersceeded with better ones. The manufacturer may just want to sell more product. -Michael

It's too cold now but the guys were talking about a cross country jump they did last year where they popped at 11k and glided about 10km to the DZ. That sounds like a really really fun hop & pop to me. -Michael

So I'm still a newbie but I'm considering getting my rigger "a" CoP in the future. This needs to start with a good indepth technical knowledge. So I'm wondering if there is a good book to get into the technical part of rigging? -Michael