audacium

I fear and guess abby meant Jimmy Hall the paraglider? Abby, please let us know when you have more information. Very sad ... it seems to become more and more ... -- Eduard

Full flight through turbulence will allow the best chance of making it through without a collapse. If a collapse occurs, then a half brake pump, similar to inflating closed end cells is recomended. I fail to see how being in a braked configuration will prevent a collapse. In my opinion, a collapse occurs when the angle of attack gets too small or even negative. So in order to avoid a too small angle of attack you must increase it. You increase angle of attack by braking. So I would say that with a braked configuration you will have a lower chance to experience a collapse. On the other side you must be careful that you do not create too high an angle of attack for the air you are flying in, i.e. in case of entering an upwind / thermal or getting hit by tailwind. At least this is how it works for paragliding wings, and I do not see a reason why it should be different for skydiving wings. -- Eduard

That is correct, but to be fair with him, meanwhile he is doing real infinity @all: And you cannot do infinity tumbling because foremost (as mentioned already) a skydive wing is not efficient enough, it would lose energy too fast while a paraglider wing suited to infinity can carry the energy through the manoeuvre, mainly because of much higher aspect ratio (thus better glide, less induced drag). Such a glider must be extremely dynamic on the pitch axis (virtually no damping). (They will usually be very dynamic on the roll axis as well.) There are other factors as well to make a wing able for infinity, for example the trim must be chosen correctly, but I am not a manufacturer of such wings so I do not want to speculate about details. Best, Eduard. -- Eduard

Hi, I will add my voice that I think you should be careful with your towing system. In paragliding towing is quite popular, and for towing special systems are used, e.g. break points, towing systems with varying force etc. A fixed rope as you seem to use it can quickly lead to really nasty accidents, as mentioned already it is called a lock out where your canopy flies away from the towing direction straight into the ground without a chance to recover. A rope with 60 m seems ridiculously low to me and asking for problems...in case of a bad situation (lock out) you have nearly no time to react. Have fun with your canopy, still

Hello, Here a translation to English. As I do not know all the technical terms in French it might be that I did not translate everything exactly. However, the thrust of the message should be correct. > il m'a été donné d'examiner la voilure de Karina qui s'est gravement > blessée l'été dernier suite à une autororation sous sa voile Ace 240. > A l'observation des photos de l'incident et l'examen de la voile, il > apparait qu'une clé s'est formée sur un des brins supérieurs de > commandes de freins durant l'ouverture bridant la demi-voile à gauche > et après avoir libéré les demi-freins le phénomène s'est amplifié car > la voilure a regagné sa vitesse propre sur la demi voile à droite qui > n'était pas capturée par la clé. > le type de construction des commandes supérieures de ces voiles Ace et > Black Jack fabriquées avant décembre 2004, favorise ce type d'incident > car les 5 brins supérieurs n'ont pas la même longueur, les deux brins > les plus extrêmes sont d'une longueur de 8 à 10 centimètres plus > grands que les 3 autres internes. > à l'ouverture, le brin le plus extérieur bénéficie d'un "mou" > qui ne demande qu'à s'enrouler autour des autres brins, la trace de > brûlure en atteste. > Après discussion avec le constructeur de ces voiles, il est recommandé > de raccourcir les 5 brins à égale distance, ils restent attachés à un > total de 2 caissons par côté et vous ne touchez pas aux brins > internes. > Par contre avant de raccourcir les brins les plus extremes , je vous > conseille de les examiner et s'il portent des traces de brulûre de les > changer. > Vous pouvez contacter Consolidated Rigging si vous êtes concerné ( > c'est à dire si vous avez une Ace ou une Black Jack d'avant décembre > 2004). > Vous obtiendrez de meilleures ouvertures de toutes manières car une > amorce de capture de commande de freins peut se transformer en > orientation puis se libérer par elle même sans que vous l'ayant > mentionné... It was my task to look at Karina’s canopy who was very badly hurt last summer when her Ace 240 started an autorotation / spiral which could not be stopped. After looking at pictures from the accident and at the canopy it seems that a knot had formed on one of the upper brake lines / in the cascades of the brake lines during opening. This pushed / turned one half part of the canopy to the left, and after releasing the brakes from their pre-braked setting the problem became worse because the canopy started to fly at trim speed on the right side which had not been subject to the knot. The kind of construction of the upper brake lines of the Ace and Black Jack canopies which have been produced before December 2004 are particularly inclined to suffer from this type of incident as the five upper brake lines (per side) are not of the same length. The two outermost brake lines are 8 to 10 cm (3 to 4 inches) longer than the three other inner brake lines. During opening the outermost brake line is not under tension but loose, this is just asking to wrap itself around the other brake lines, as can be seen from burn traces. After discussion with the developer of these canopies it is recommended to shorten the five (upper) brake lines to equal length, they remain attached to two cells per side and the inner (upper) brake lines are not to be touched. However, before shortening the outermost brake lines it is recommended to check them and to replace them if they show burn traces. You can contact Consolidated Rigging if you are concerned (that is, if you own an Ace or Black Jack that dates from before December 2004). Anyway, you will have better openings as a beginning line over of the brake lines can free itself during opening without you even noticing. -- Eduard

For those that speak German: I prepared a German translation of this text for the German base association. Of course I am happy to share it with anyone interested. -- Eduard

I have about 50 jumps terminal on a FliK Vtec 266 (don't know whether this is significant for you...) and I have just used the stock large hole mesh slider. Openings were quite hard in the beginning, now they are perfect with enough rolling of the nose and direct stow. Going smaller seems unnecessary and wrong to me, also, certainly the first people to ask are the ones from Apex, right? Rock Dragon --> different canopy --> different slider... -- Eduard

In Englisch "Deadly Connections" -- Eduard

Hi Robyn! Yes, the beer festival (Oktoberfest) is the bomb!!! Either you love it or you hate it, but it is a must see

Hello, to my knowledge there are no jumpable cliffs in Germany apart from spots in the Alps in southern Germany. Only heard about how they got jumped by some Germans and also a certain excellent Russian wingsuit flyer :-) and did not jump myself, they probably are quite hard anyway. So, for cliff jumping you would have to go north (Norway) or south (Italy, Switzerland, France, etc.). @Robyn71: I suppose you speak German :). In this case I would suggest to have a look at our German base association website : www.base-jump.de and check the contacts (in your case probably region Hessen is of interest for you). For cuteness you have to find out yourself :). If you do not speak German let me know via pm and I can send you the contact for Frankfurt. And in case you find yourself near Munich or have more questions let me know anyway, I will be happy to help you. Best, Eduard. -- Eduard

Acknowledge Hannes! The question bore a certain "suggestion" I dare say... -- Eduard

Before people start wild guessing...yes he did start skydiving with the purpose of learning base jumping, and he got himself an experienced mentor, so no worries... Have not jumped with him though. -- Eduard

Hello, I would opt for a deep stall, especially reading it was a clapped out canopy. Porosity might have gone up so much that the canopy, once in deep stall, does not come out of the deep stall by itself because too much air goes through canopy and flow over profile cannot pick up. Probably it was induced by the toggle / riser input, but then the slight kink in the canopy, while fully open, and the straight sink with that sink rate look to me like a deep stall (and not full stall). Eduard. -- Eduard

Not entirely true -- Eduard

You are right, but what does this have to do with my post ? -- Eduard

Pulling by the pilot chute creates a force approximately straight opposed to the flying direction and thus a torque around the center of gravity (compared to the situation without pilot chute). So, the whole system will rotate a little bit backwards (again compared to the situation without pilot chute). This increases angle of attack. -- Eduard

Regarding pilot chute size and stall point: Well, as described it definitely makes sense in theory. As the pilot chute trails behind in flight, it increases the angle of attack of the wing by pulling on it. The larger the p/c and thus the more drag, the higher the angle of attack will be and thus the closer the stall point will be. So, the reactions of the canopy as described by "eUrNiCc" fit nicely into this thinking, it simply makes sense. But it is an interesting question just how much the angle of attack is changed by pilot chutes and whether it is the main explanation for what eUrNiCc experienced. As an added complication we would have to research the difference between single and multiple attachment points of the pilot chute (see Apex Multi configuration).

@Calvin: I wanted to know the same thing, and I emailed Chrigel to ask him for the song title (he is the guy flying with the helmet cam). I will let you know when he answers. -- Eduard

Paragliding is the bomb. I started skydiving first several years ago and then later started base jumping. When paragliding was proposed to me two years ago I first thought the same thing, "nice but lame". Well, get out on a nice day in spring or fall in the Dolomites or in Fiesch and go ride some hard thermals and lift up to 13.000 ft, with the glider constantly rocking and twitching because of the alive air. This is not lame. Or go flying acro, feel the speed and the energy conservation of the wing. Seeing acro videos and the incredible things you can do with a paraglider finally made me start paragliding. A paragliding wing is for me much more interesting than a skydiving wing because it is more efficient and much more powerful. It kind of has its own mind and feels very much alive. I love skydiving and base jumping, but the pleasures of paragliding are for me just as good if also different. Thanks to Calvin for posting the link, I had overlooked that video before. Keep up the flying spirit! -- Eduard

On Friday and Sunday I flew past the wall with my paraglider. In my opinion, this is not jumpable slider-up. Also for wingsuit the talus comes out too early. I have not done a rock drop yet, though. So, no new big wall unfortunately... Edit: Just saw that Miko already did a rock drop... -- Eduard

Almost all my terminal jumps are with large mesh and a 36' F111 p/c, most were with a FliK Vtec. In the beginning openings were ultra-hard, but with some more jumps on the canopy, direct stow and rolling the nose several times the openings are perfect now. So, no worries with 36 and large mesh, in case the opening is too hard you will have to experiment what works best for you...just rolling the nose in various degrees, or changing slider to fine mesh etc. On the other hand you will not snivel in due to fine mesh (well...do not pull super low still...), so you can also start with fine mesh and then switch later if the opening is too slow for your taste. I also tried other combinations, e.g. fine mesh and 32' zero-p pilot chute. It was fine as well, but I prefer the stickiness of normal F111, also for my taste a 32' is just too small and kind of gets lost in the pouch. But all this is highly personal. For me it is nice to only use the large mesh because then I do not need to change slider for sub-terminal. With my configuration it is enough to roll the nose more or less to adapt openings. You have to find out what works for you. As Tom said...you'll be fine...have fun...terminal is best -- Eduard

Thank you Douggs. -- Eduard

??? According to the above calculations, a 36 generates about 70% of the drag of a 42. i.e. 260 lbs at terminal. So, what do you mean? That is not really the problem resp. the point. The drag equation "works". What can be discussed is how you come up with the drag coefficient or which reference area you use. For reference area I used a very simple approach and just took the area which should result if the pilot chute is flat on the ground (which it obviously is not if inflated). Whether you come up with a value for the drag coefficient via a theoretical model (which would require a complete solution of the Navier-Stokes equations for a flow around a bluff body what even nowadays is a pretty complex problem and passes most computer capabilities) or from empirical tests does not matter for our purposes. Empirical tests for the drag coefficient of an open half sphere or a round parachute usually result in a C_w around 1.2-1.3 or so. So, as a first approach I think the drag equation scales pretty well and we have no reason to believe the drag coefficient will be drastically different for pilot-chutes of different sizes. And as mentioned above, the difference in drag is of course bigger than one pound. Only recently (past few years) it has become possible to do meaningful calculations on such flows. A lot of research is still semi-empirical. The flow around bluff bodies has some special problems which make it usually impossible to use some very nice simplifications (Prandtl etc.) which can be used for streamlined bodies (like a wing for example). But aerodynamics is not my specialty, maybe someone from the field can add to or correct my thoughts. -- Eduard

What the maths? Drag equation: D = 1/2 rho v^2 C_w S whereas rho = 1.225 kg/m^3 v = 50 m/s C_w = 1.2 (approximately) S = pi r^2, where r = 0,53 m (approx half of 42') results in D = 1642 N which is about 369 lb, ie roughly 350 lb as calculated by Nick. -- Eduard

The recent designs (Omega 7 etc.) only have negligible "ears" any more, because - as you said - the ears always have been rather a marketing ploy than an aerodynamically sound construction. Probably they do not have any effect or even hurt performance, and I guess this is why they cut the ears of on newer designs... -- Eduard