audacium

I stand corrected, when I answered I was thinking of level flight with constant lift which obviously does not apply here as we were talking about more lift due to more speed, sorry for the confusion... -- Eduard

pm sent. -- Eduard

The above is not correct, sorry, at least not in this generality. The speeds for best glide and for minimum sink are in general NOT the same. Practical example: For paragliders (another unpowered wing) they are definitely not. Best glide usually happens at trim speed (ie, without any inputs), while minimum sink happens when some brake (about 20%) is applied. But the wing goes slower of course, glide ratio gets worse. Theory: Best glide happens when the wing is most efficient, and that is when total drag is at a minimum (which makes sense). Do a calculation for example with one common polar equation (C_d = C_d0 + k c_l^2). Minimize total drag, and you will arrive at the exact same condition for best glide, and vice versa. The calculation for minimum sink is different and will result in a worse glide ratio. Minimum sink happens at values for the lift coefficient much higher than they are for best glide (and thus at slower speeds). In fact, total drag rises more than lift increases and thus glide ratio gets worse (again, paragliders glide worse at minimum sink, but when using thermals it is min sink which is relevant but not the glide ratio). Also, two things should not be mixed: how the wing flies in the air, thus, its inherent glide ratio, etc., and what that means for glide ratio etc. relative to the ground. For better penetration into a head wind you decrease, not increase the angle of attack (I think you simply wrote the opposite of what you wanted to.) Exactly, and this is what I was saying in reply to raymod2 "more lift means more induced drag": in the discussed case of coming out of a fast turn, when hitting the gates, more lift is generated but not necessarily more drag. When the canopy rises instead of levelling out it means lift grows proportionally more than drag rises, right? All the best, Eduard. -- Eduard

Thanks. I think min drag means best glide, while min sink happens at max lift which means more drag? Hm, I think we are mixing two things: If I do not change the configuration of my (unpowered) wing then going faster with this wing will produce more lift but less induced drag. I think what you are saying is "if I increase the angle of attack and thus increase the lift coefficient C_L, I will go slower and the induced drag will rise (because I go slower)". But this is a changed configuation. I was talking about coming out of a carve turn or so with increased speed, but with pilot not giving any inputs for a moment (that is, when leveling out) What do you think? -- Eduard

Actually, induced drag diminishes with more speed, it is parasitic drag that increases with speed. So, in order to know whether total drag increases with speed you have to know where you are on the "total drag curve". That is an interesting question: Are canopies at the minimum of the total drag curve when flown at trim speed and without any inputs from the pilot? It would be entirely possible for the canopy designer to move this point a little bit towards "accelerated flight", ie, after front riser input or after a steep turn.Then a canopy would have its best glide at higher speeds than trim speed. Does anyone know about this? -- Eduard

Honestly, at the moment I have no idea, what you say sounds reasonable, but I could imagine that a boundary layer over ground extends much further. I will try to find data. Well, falling out of the sky is maybe not the exact description :). But there is definitely a wind gradient effect as opposed to hitting a rotor. Typical case: people landing in high winds on a large field (so no turbulences around), in deep brakes, and closer to the ground the glider stalls. Most people will react fast enough and put the hands up so they land safely, however, sometimes it happens too close to the ground or they react wrong. I experienced this myself, at least the glider becoming soft. Sounds like a very good idea! -- Eduard

Boundary layer...I would apply that rather in aerodynamics around well defined bodies, but whatever, I am not a meteorologist

Hi Ray, These got to be two of the finest posts I ever read in this forum!!! (Even if I am not an oldtimer permit me this exclamation of joy :)). Thumbs up! -- Eduard

Hello all canopy-people, Sorry, I do not have much time, so I will just throw this in, without having thought much about it, maybe it is still of interest and my idea goes in the right direction. I think the effect of the "wind gradient" has been forgotten until now and it might play a role in this discussion. Wind gradient simply means, that wind will get slower closer to the ground due to the friction. So, in higher winds the wind gradient will be stronger. Being in a wind gradient means that the canopy is always entering the next layer of air (which moves slower) kind of too slow (risk of stall if you are in deep brakes), so maybe it has an effect when in full flight / carving the canopy in that the lift of the canopy will be less than in a weaker wind gradient. So this might explain why maybe indeed you have to set up a little bit higher in high winds. But some people seem to experience vice versa :). It seems most arguments in this discussion have relied on a homogeneous wind velocity from set up height to ground which is not exactly correct I believe. Whatever, just some food for thought, I hope you get the idea what I am trying to say, now I have to continue working, sorry, maybe I can join the discussion later in the week. -- Eduard

This is so sad. I met Peter several weeks ago in Italy and found him to be a very friendly and welcoming person. He invited me to come jump with him in Switzerland, I wanted to call him soon to tell him I could come in August, and now I will not be able to share more jumps with him - I am sorry Peter! Condolences to his family and friends. -- Eduard

Agreed and good point, so you should not open your chest strap to the point where you can fall out. I think one of the main reasons to cut away comes from twists which make the canopy spiral, so for me I will try to avoid twists in the first place. I think the chance of twists rises dramatically if you leave the chest strap completely closed. Yeah, that is very well possible, probably if I flew a small elliptical canopy I would also contact the manufacturer and find out what they say about stall properties of the canopy. -- Eduard

What if I'll have to cut away? Why should I cut away an open and normally functioning canopy? Otherwise, I would probably not bother at all about doing stall exercises...would I? A wide opened chest strap improves the performance of the canopy, and it helps avoiding riser twists, as mentioned. Oh, and by the way...did you notice all the swoop pros flying with wide open chest straps? Seems they have no worries about cutting away here... Is it reasonable to stall small elleptical canopy? I do not know where it begins to get "too hot" and down to which canopy size / platform a stall is well manageable. But in general I would say...do it high (and possible over water with a rescue boat)...then yes it might be very reasonable. The more you know about your canopy the better. -- Eduard

Hello Brian, Thanks for the nice article. I think some things should be added. First, when stalling the wing the wing will stop flying and the pilot swings forward. In this phase the pilot will experience a feeling like falling backwards which can be weird at first. In this phase the brakes have to be kept down under all circumstances until the pilot swings back under the wing, otherwise the resulting surge will be huge (even worse if it is asymmetric due to asymmetric release of brakes) and hard to control. Second, to help avoid riser twisting the chest strap should be opened completely in order to have a greater distance between the three-rings. Third, it might make sense to first practice stalls on a more forgiving wing, possibly rectangular and big. Stalling a small elliptical canopy could become challenging. Fourth, before completely stalling the wing one might just work several times on finding the stall point. Fly slow, pull down the brakes a little bit more, and just when the wing is about to enter the stall release the brakes quickly and symmetrically and control the following surge. But once the pilot begins to swing really forward (that is, you are beyond stall point), brakes should not be released but kept down until pilot swings back under wing (see above). Thanks, all the best, Eduard. -- Eduard

Hi John, Usually I stick to the following rule: slider-down: hand-held slider-up: stowed But also I mostly do slider-up jumps, and for me there is no benefit in going stowed on short delays. I yet have to do a slider-down jump where I do not have enough space at exit point to prepare the pilot-chute for hand-held. Otherwise, the thread contains everything I could yet say. -- Eduard

As mentioned, paragliders can flip, parachutes cannot because they are not efficient wings compared to a paraglider. Speed alone is not the key, it is the wing keeping the energy which he got from an energy-inducing manoeuvre, and that is why you need an efficient wing. -- Eduard

This is very sad, my thoughts go to his family and friends. I met him the first time last year in Norway and met a a fantastic jumper who was at the same time simply a very nice, friendly and welcoming human being. I was looking forward to see him again this summer. I jumped today at Brento and this jump is dedicated to Coombsey. RIP. -- Eduard

Hi smd7, Sorry to hear you want to quit jumping. But if your heart is not with it anymore it is probably better to stop and keep the good memories. Regarding your search for a harness: If you have not done so I would also search paragliding forums, for example www.paraglidingforum.com. As I live in Europe I do not know that many US paragliding forums. From my experience, you can pick up a nice used harness for really little money. There are astonishingly many people out there who bought new gear after the license, did 20 flights, then had their gear lying around for three years and selling it because they realize they are not into flying. Also, you might try calling some local paragliding schools, they could help you as well. Good luck, Eduard. -- Eduard

Hi George, I went from Munich, Germany, to Kjerag last year by car, I travelled through Danmark and took the ferry from Hirtshals to Kristiansand. Believe me, this is already long enough. I left Munich at 8am in the morning, I had to race like crazy to catch the ferry at 8 pm in Hirtshals (DK), and I finally arrived at 3am in the night in Lysebotn. Going from Kristiansand to Kjerag takes a long while as well, even it is not so many kilometers, but you cannot drive fast in Norway (or you should not, it might get expensive :)). It was in total approx. 1500 km and I was pretty tired, not ideal conditions for jumping the next day... Unless you visit someone and make stops to have breaks, going through Sweden and without the ferry is imo too much. It will take forever, and I think the additional fuel costs will be equivalent to the ferry costs. Do yourself a favour and take the ferry. Just book in advance so that you have good rates. Best, Eduard. -- Eduard

Hello, take a collapsible bottle, as mentioned. I use it on pretty much every jump where I have to walk more than 30 min and it works perfectly. You can take enough water with you (there are bottles up to three liter I think), just put it in the stash bag and drink during a break if necessary, and when not needed any more I usually stuff it into the pants or the jacket (no belly pocket needed), they get really small. Only if you do not want to take small breaks during the hike a Camelbak makes sense in my eyes. Otherwise it is just another bulky piece of equipment that uses space and distracts me. I did not like it when I tried it on some jumps. There are various manufacturers for the collapsible bottles, Platypus being one, I have some from Deuter (but I live in Germany). -- Eduard

Just remember that from the ninth of June till the ninth of July the FIFA soccer world cup will take place in Germany. Depending on whether you like soccer or not (especially soccer fans...), traveling and staying in major cities like Berlin, Munich etc. (where the games will take place) might be a nuisance or not . -- Eduard

Hello bert_man, Just a quick explanation: I think it is very cool for everybody who has got some basic training at all, the more the better. So, I am very glad to read you had training. Sorry if my post was maybe a bit dry, I just wanted to raise awareness to everybody that especially in our sport where really bad injuries can happen we should always perform life preserving measures - even if we doubt the person is alive at all or will make it. That is, unless there are absolutely clear signs like the ones RhondaLea just brought to us (thanks). Otherwise: No one is dead unless declared dead by a professional - usually a doctor. And I perfectly realize that most people who have taken some basic training cannot go back regularly, but my gut feeling would be to say, maybe once or twice a year a refresher training would be very helful. Best, Eduard. -- Eduard

This is the impression that I get as well. I attended an Outdoor Emergency Care (OEC) course with the ski patrol a few years ago, and have CPR and AED certifications (not current, but I still remember). Unfortunately you are wrong to assume you can decide clearly whether a person is dead or not. I have some medical training as well, working for the Red Cross as a first aid responder etc. At least in Europe we are _required_ to perform CPR as long as it takes (that can be hours and more) unless 1. there are absolutely clear signs of death (head detached from body, body in state of decomposition, rigor mortis, and some other) or 2. a doctor declares the person dead. There is a reason why a doctor must do this (possibly with a brain scan etc.) and not me or you with some basic training (compared to a doctor). If a body is heavily wrecked the blood pressure may be so low that you have no chance to ever feel it - especially in a high stress situation when you have seen the jumper going in. The pressure may still be enough though to let the person live on until proper medical help arrives. Yes, in many cases even a really badly injured person will still have his / her conscience and can tell you what or where it is hurting. But in many cases as well the person will be without conscience, and then it is time for a doctor to decide whether the person is dead or not. So even if a jumper is really badly injured, without conscience, losing blood etc. and one thinks "jumper is probably dead" one should really stay there and perform basic measures that one has hopefully learned in CPR training or wherever. Sorry, do not take this bad, but with some probability you may remember what you learned a few years ago (but with some probability you will not), but even if you remember you might just lack the necessary routine to perform seemingly simple things like only feeling blood pressure. It is one thing to have felt and checked vital signs in the quiet atmosphere during your course, and another to do the same things under high pressure when a real person might be dying. And with the experience lying back several years it will only get more difficult. So, while I applaud everybody who has taken such courses I dare say it makes very much sense to get refresher trainings from time to time. I am doing this at least once a month, and I can feel the difference when the break was very long. It is the same when you have been out of jumping for some time. bsbd. -- Eduard

Hm...I think that is pretty much what Yuri (outrager) was saying all the time. A buzz in his definition is done in a safe manner so that unintentional manouvres cannot endanger either the pilot under canopy or the wingsuit pilot. Did Yuri anywhere ever mention at what exact distance he would "buzz"...? No...and I am pretty sure in reality everything would just have culminated in a civilised discussion about "where does my personal safety distance" lie. I did not ask Yuri but I bet a safe buzz in his definition does not mean passing at 10'. You seem to assume he is talking about buzzing really super close (like 10') what he never said. So instead of just calmly asking "well, how close do you think is safe buzzing for you" I could read from your side mainly pretty strong accusations ("tried to kill me with a reckless stunt") pretty childish threats and attacks towards Yuri (again: he is one of the "unreal" wingsuit flyers of the world). And by the way, I seriously doubt you can consistently judge the difference between a pass of a wingsuit flyer at 300' and 500'. So just relax, I do not think you are so far away from each other. Just do not assume things people did not say. Now Yuri, please don't le me down, I hope I understood you right and I am on the same path as you . -- Eduard

Main idea is to my knowledge that the bridle is better protected when routed through the middle, especially when tracking. That is also why the Gargoyle does not need a tucking pin cover flap as the Vertex2 for example. I would even suppose it is not ideal to route the bridle from the top with a Gargoyle when you are doing tracking jumps as there might be a danger of loosening the bridle and undoing the pin. Sure the flaps will take some load but I guess that is why Morpheus recommends routing through the middle. But that is my own understanding, maybe other reasons are more important that I am not aware of. -- Eduard

Well, I am flying a Sonic suit now, and I am sure it is exactly the suit (apart from design) that Babylon is flying now. In case of coubt I would just ask Vincent from Sonic, he will be happy to help I am sure. Feel in flight, quality and craftmanship are excellent. www.sonicflywear.com -- Eduard