IJskonijn

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Posts posted by IJskonijn


  1. I agree, the jumper him/herself need to be on top in terms of sizing and measurements, or find a capable rigger to help with that.

    I'm not specifically referring to a certain type of rig (although I am aware of some problems with some rigs in that respect), but I'm also referring to getting the correct size. Overstuffing the reserve tray and/or the main tray is very unlikely to improve the openings. This is both on the jumper (to know what canopy type and size they want to jump) and on the manufacturer, to know what size rig conforms to what types and sizes of canopies. Pack volume might be good to know, but unless we can get a globally uniform and reproducible way to define and measure pack volumes, it isn't going to be useful.

  2. As already said, it needs to work and it needs to fit you properly. All the features, colours, trim and other crap on a rig won't help you one bit if the rig lands in a different place than you do.

    Also, if the corners are so sewn in ("dynamic" corners) that the reserve freebag is having a tea party on your back after you punched it, that's no good either. There's no colour scheme in the world that looks good with lots of blood on it.

    Only once those are all taken care of, then you can go to town with all the nice little features and gimmicks and colours that they offer.

  3. Does downsizing solve a problem you currently have? If not, there is no reason to downsize. If it does, go ahead and downsize, but try not to create other problems down the road.

    Possible problems to consider can be: Being bored out of your skull under your current canopy (image you flying a Navigator 280 for 500 jumps). Not being able to jump in certain weather conditions (higher winds being one of them). Stopped learning under your current wing (with the wing being the limiting factor, not your mentality).

  4. I think there are quite a few mounts available that make it more snag-resistant. No camera mount is fully snag-free, and for that matter no helmet is fully snag-free!

    I got in a wrap (CRW) a while ago, where the lines of the other guy's canopy got stuck in my neck behind my half-shell helmet, not even on the camera mount. Since I had a camera on it, I had a cutaway system on it as well. And because I was able to cut away the helmet, we could solve the wrap without the bottom guy chopping.

    Don't rely on adhesive mounts to break off in case of shit happening. Rely instead on some system that is DESIGNED to release easily and quickly when necessary.

  5. In that respect, I'm less worried about people with a camera and two DSLRs on their helmet than about people with a gopro. You don't slap 3kg of glass on your helmet without thinking hard and deep about the consequences and its effect on your jump...

  6. faulknerwn

    I have never ridden a Smart on a true reserve ride but I jumped a demo 135(?) at a boogie. It was docile but super flat trimmed. I was test jumping it so I tried using rear risers and such - I could not use the rear risers at all without stalling it. Which could be good or bad depending on the situation you are in.



    If I understand canopy flight correctly, trimming it like that would put the canopy in a minimum sink configuration, which would mean maximum airtime, and thus maximum decision time. How was the stall behaviour on toggles? Did it stall immediately or did it need quite a bit of toggle input for quite some time before stalling?

  7. An easier solution (if you want a good binding) is to get a logbook with the cheap plastic binding, and then take that to a copyshop and pay them to put a metal spiral in it. If they can't do that, they're not worth your money anyway.

    Or, if you want, I can send you the basic files I used for my logbook. Adjust as desired (you might not want photo's of crazy-awesome CRW formations on the covers ^_^), and go have fun. Seriously, designing a half-way decent logbook isn't rocket science.

  8. In the past, I've had plastic spiral bound logbooks. They suck indeed. My last two logbooks are of my own design with all the space I want, precisely how I want it. I like logging, so I rather spend time to design a good logbook for my purpose and money to have them printed and spiral-bound with a metal spiral at a copyshop. The metal spiral hasn't failed me once, and the booklet contains 5 jumps per double page, 200-ish jumps total.

    The whole printing and binding part was surprisingly cheap as well. With fullcolour front and back (some nice photo's went on those pages) and the rest black-white, using heavy (150gr/m^2) paper and a metal binding, cost me somewhere around €20 for two booklets A5 sized. Totally worth it.

    I'm going to adjust it a little bit, and have some more printed soon since my current one is almost full.

  9. I can't speak for the other clubs, but at my home club only the pilot uses a radio. There is a big-ass T indicator (bright orange, 8 meters long) on the landing field, and there are good landing fields all around for a LONG LONG way.

    Before the jump, students get a thorough briefing on the supposed pattern, wind direction, exit point and the land marks around them and where they are in relation to the landing field.

    And yes, we occasionally have a first-jump student take a cross-country jump because they forgot to look down between their legs, but those instances are few and far between. I don't think you solve that with radios, given the amount of stories I heard where the ground instructor heard the student radio just fine, but the student claimed he didn't hear anything! Some levels of stupidity are just unsolvable.

    We mostly solve the lack of radios by good thorough briefings before-hand. And even dropping just three students out of a C182, most of our instructors tend to take two passes to put them out.

  10. Radios have plenty of downsides as well, so it's not something that no student should be without. In fact, I know of no DZ here in The Netherlands that still uses radios for their student training.

    Rather, I think no student should be without an instructor watching out for them either from ground or from air, up to and including until they are properly debriefed and back in the hangar. My home club has a club rule that there always needs to be an instructor or assistent instructor at the DZ when students are jumping, since the DZ is off-site from the airfield.

  11. Just had a ride on my PDR 193 this weekend. No linetwists on opening, slow, steady, never heard of harness turns, sinking like styrofoam on water, feels like a battleship when turning. Stood up the landing easily. All the things I want in my reserve.

  12. Wave the PSB in their face. Any skydiver that thinks any part of their equipment is truly maintenance-free and without any possible fault is either an idiot or has just woken up from whatever rock they lived under.

    And if you don't plan on exceeding 27.000ft, compliance is mandatory at any opportune moment between now and 31 May 2020. With Dutch 6-month repack cycles that's two or three repacks before that deadline passes.

  13. benlangfeld

    Were you not required to pay for temporary BPA etc membership to jump there? Most of those countries say that’s a requirement, just like in the US. Is that just not enforced?



    When I was in the UK to jump (although on my Dutch license, I don't have a USPA license), it was enough to provide proof of 3rd-party liability insurance by the Dutch KNVvL association. Without that, I would have had to buy BPA membership or some such thing to have enough 3rd party insurance. So I think for most countries, it is not so much that you are required to buy membership, but that you are required to have 3rd party liability coverage. If you cannot prove that you have, then buying a membership is a good way to have that coverage.

  14. 15 megapixels means nothing at that level. The added value of having a really good stills camera with a good sensor, aperture, high-quality lens and equal image stabilization is enormous. Same for video. Action cameras are getting pretty good nowadays, but full-sized video cameras are still that much better. Also, when you're getting paid big bucks for video/stills (maybe some sort of one-shot promotional event), you can't have camera failure as an excuse for not having the shot. So you bring two cameras.

    Plus, a very hard opening can kill you. At some point, it doesn't matter anymore how much weight is on your helmet. And I see videographers more often than not make canopy choices specific to their situation. Some canopies are known for hard openings, some are known for having a cup of coffee in between linestretch and full inflations. Dacron lines also help, as they are more elastic than microline or vectran. Slider choice and pilot chute choice also influences the force of opening.

  15. Haha! The way this topic turns out, it seems like it's been flipped over by turbulence!

    Me being the physicist that I am, I'll happily join the discussion. From an aerodynamic point of view, what really matters is the force per unit area on your wing (or strut, or control surface, or line, or whatever). Mass (in kg) is irrelevant insofar that you need a (non-fixed in both direction and magnitude) vector called acceleration to get the force from the mass (Newton's famous F = m*a). As mentioned, the mass of the system stays the same no matter how hard you whip around on front risers, but the force that your lines have to hold sure does change!

    So the technically correct (the best kind of correct) definition of wingloading would indeed be one of N/m^2 (because imperial schimperial), rather than kg/m^2. Which would be weight per unit area. And since weight is changed by a change in acceleration, wingloading does change when you give some sort of input under canopy.

    But in most cases we can simplify things by saying the acceleration is constant and equal to the local earth gravity. In that case, definitions of wingloading in kg/m^2 are equivalent to those in N/m^2, so under that simplification this entire discussion is completely pointless.:):)


  16. dthames

    Turbulence is pretty short lived, so just keep flying as normal is what I do.

    I am lightly loaded and hot weather thermals (not what I call turbulence) have both bounded me around and kept my decent rate very low. When jumping at a DZ that you are familiar with, it is not hard to learn where the thermals tend to be. It is also useful to know that if you need to get back from a long spot. I fly with a Flysight and also listen to my vertical speed under canopy. It is interesting to see how the type of ground you are flying over often changes your decent rate. Plus or minus 5 MPH in the vertical is not uncommon. My average vertical is about 12-13 MPH.



    In hot weather, it pays to think ahead about where the turbulence will be relative to the landing area. That type of turbulence is easy to predict, as surfaces like tarmac or gravel heats up more in the sun, and the air boils off those surfaces faster than off the (relatively) cool grass, causing turbulence.

    So in general for landing area, you want something smooth all around. With that I mean that it is way better to land in the middle of a large grassy field, rather than at the edges where the boiling air is likely more violent and can throw you around much more (not good when your altitude is measured in single digits...).

    Also, avoid the peas for the exact same reason.

  17. Last time I was in Florida, we hit the turbulence on hot days at altitudes up to 5.5kft. For me, flying through it with increased airspeed is impossible, since I won't have arms left if I have to frontriser for 5000ft. So I took the paraglider approach, to fly through it with a little brakes to keep a good feel for what my canopy was doing. The turbulence was never so bad though that I feared for a canopy collapse, flying on a Lightning 160 at 1.35 wingloaded. Then again, Lightnings tend to recover quickly from partial or full collapses, so ymmv.

    Another disadvantage of spiraling around is that you are more likely to lose sight of the other canopies in the air. An unplanned canopy collision is bad news with or without turbulence.

  18. Also take into account that the French have some crazy strict rules on canopy size... http://www.ffp.asso.fr/dt046-nouvelle-reglementation-relative-a-lutilisation-des-voilures-principales/. You may not be allowed to jump your own canopy, because they judge it to be too small.

    Then again, I've once been told by a French jumper to just fake a logbook with enough jumps if I was ever to go jump there... This is obviously not advice, just an anecdote on how some French view their own rules.

  19. JohnMitchell

    I still wonder why so many sources say "don't flare a biplane". I've seen it done with a very good landing. Anyone with a definitive answer?



    Page 4 of the dual square report (found on the PD website: http://www.performancedesigns.com/docs/dualsq.pdf) says:

    PD dual square report


    Landing a personal biplane proved to be easy with large canopies, small canopies, heavily loaded canopies, and lightly loaded canopies. Flaring the front canopy seemed to be the preferred method of landing. However it must be noted that flaring the front canopy, or both, did not produce a significant effect in the landing. The canopy would pitch in attitude, but it did not plane out or slow in descent rate much if at all. The descent rate on all canopy combinations was very slow, even in full flight.

    Recognizing the student and novice jumpers propensity to flare high, combined with the non effectiveness of a dual square flare, leads us to believe that not flaring at all is the best way to land a dual square.

    conclusion: If a biplane is present and the jumper has directional control, leave the brakes stowed on the rear canopy and fly the biplane using gentle toggle input on the front canopy. Do not flare either canopy for landing. Be prepared to do a PLF.


  20. Rise of the Zombie Thread!

    I'm too lazy to scroll back through the thread and see if this one has been posted yet, so I'll just post it. http://www.performancedesigns.com/docs/dualsq.pdf

    If ever I find myself in a stable flying two-out situation, I'd do minimum of inputs (as in, enough to ensure I land somewhere that is not high-voltage or will otherwise kill me), but keep it at that.

    Also keep in mind, the most likely way to get a two-out is if you burn through your altitude, deploy your main while your AAD also wakes up. In that case, there's not a lot of altitude left to mess around.

  21. Assuming that the pilot wants us to leave (I know most pilots at my home club will keep you inside, to avoid messing with cg during an already VERY busy time, and because less weight doesn't actually help them improve glide angle), I'd be happy to exit anywhere above ~600 feet. But in that case, I'm throwing my reserve ripcord back in the plane!

  22. Mark.Carroll

    And I hadn't thought of a fabric sign because I thought it would be hard to keep it flat and legible while it's flapping around. Perhaps that's the ticket.



    That could very well be the problem with fabric. But the best way to find out is to test it. Easiest test would be to grab a piece of fabric, sew the reinforcements and handholds to it, write some gibberish on it with a permanent marker, and jump it with someone else filming it.