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Everything posted by dorbie

  1. Seems like an awesome idea, it's basically a jump with a selfie stick. Don't let hindsight skew the assessment. How he responded to the emergency is the issue, yes he should have been more ready to ditch the prop and/or execute EPs. GoPros are pricey though.
  2. With the gun 7 seconds from impact after being slowed to very sub terminal, I'm calling this a probable skyhook save. The main problem is delaying EPs, holding a prop probably required faster EPs, not more screwing around. I'm not worried about the prop drop, that wasn't the plan, camera helmets get chopped in an emergency and they have higher terminal V than a plastic gun.
  3. I'm starting to wonder it the low turn = death mantra is actually creating a problem.
  4. I was taught this as a student, in particular I remember being told to never use WD30 to clean the cutaway, to be careful what oil I used (maybe also that silicone lube was best) but I might be confabulating with what a rigger once did with a closing loop.
  5. I know Carnage and Cat Videos. I don't need views, I just find it funny what goes viral. WTF are you doing David! Danger cat has an extreme skydiving accident:
  6. Yeah my best video only has 400 and I put a lot of effort into making it. edit to URL Great skydiving videos are of interest to skydivers, most whuffos have no appreciation for what they're looking at and so experienced skydivers have a challenge anticipating what interests a whuffo. There are similar effects in other areas like the demo jumper swooping the spectator line when the guy that does a straight in docile standup landing on the target gets the biggest applause (second only to the guy with the flag). My most popular video has 180k+ views because it has "skydiving accident" in the title, it's a premature deployment at 10k feet because a jumper docked on an old style leg mounted pilot chute. It's funny for skydivers but I get occasional complaints from whuffos drawn to the video title like moths to a flame because it's not a "real" accident. :-/ If you want hits, maybe try making cat videos, I hear they are popular.
  7. It's been up there for 9 years, it'd be lost in the noise these days. An early article link I couldn't track back might have helped too. If you want hits then screw up and upload the accident, make sure you hint at carnage and mayhem in the title. All this distracts from the point though. JWest where's your video? Time to put up.
  8. LOL, in all the kerfuffle I never even thought about the product :-) Go on JWest, let's see it. Here's mine: Now show me yours.
  9. Not to worry, we have outside camera footage of JWest's first camera jump. It went well:
  10. No kidding, I was in a tight spot as a junior jumper, flared early, still not okay with a fence in front of me, and about 6 feet off the ground I thought, "I could jump down from here" and let up on the toggles. Plop, belly slide, and shortened my final by just enough not to hit that fence. Effective, but only a little less embarrassing than running it out into the fence. I'm pretty sure that was intended as a joke, skydivers have been crippled showing off doing this with no pressure of an imminent collision. The advice on letting up your toggles isn't much better. Learn to carve a flat turn in a flare, practice at altitude, it can be fun.
  11. I should probably have called it induced drag there rather than parasitic drag.
  12. This depends too much on your canopy and headwind to give a single simple answer. For example in no wind rear risers will help flatten your glide slope and lengthen your glide path on most canopies although something like a pulse it's already trimmed flat and it might not help as much if at all. Too much rear riser will have more of a parasitic effect after a point depending very much on the canopy's starting trim. Front risers will typically shorten/steepen your track however that depends a lot on the recovery arc of your canopy, what's the point of getting steep if it's going to give you that energy back coming out of the corner, but held for long enough however it should shorten in under most wings. When you are flying into a strong headwind however depending on the wind speed fronts will speed up your canopy increase penetration and lengthen your glide slope, rear risers will slow you and again depending on wind speed and canopy flight speed, even if it gives you a flatter glide slope relative to the air it will steepen it relative to the ground. Brakes will have a similar effect to rears under both scenarios but are less efficient and the crossover at which the parasitic drag exceeds the benefit will happen earlier making it more prone to shorten your slope after the crossover point of parasitic drag is reached. Now consider that every one of these factors varies with your canopy & wing loading and you have a different continuous response to control input the crossover point of which is affected linearly with windspeed. Add to this the dynamic effects of any control input as the canopy has more or less energy in the short term until it reaches equilibrium and takes a different amount of time to reach equilibrium. So any change in canopy trim or brake will have a short term dynamic effect that might disguise the longer term effect, e.g. brake input will flatten you out (just like a flare) until equilibrium is reached only after that point will you start to realize the glide slope of your new control input configuration. It's too complicated and sometimes counterintuitive for simple answers. You literally have to build a model of what is happening in your head including the air speed and ground speed, and test that model against your canopy at your wing loading and see what works. When you change canopy or wing loading you have to relearn what works and doesn't, sometimes it's a matter of degrees but some canopies vary a lot, e.g. a Saber 2 vs a Pulse will definitely give you different answers in some scenarios. Other safety factors like too much rear riser can easily cause a stall and very deep brakes might too on some canopies and brake configs but WILL make you more vulnerable to a wind shear induced stall in turbulent conditions and letting up risers or brakes will cause the dynamic effect of a surge until equilibrium is reached again and you can see that this is something to be explored cautiously and perhaps at altitude before bringing it into the pattern. My advice is work on your mental model of what is happening under canopy and try to build your intuitive model around that. That model needs to factor in wind vs. air speed and dynamic short term effects. As always consult a real canopy control instructor before putting anything into practice, especially before bringing those experiments low.
  13. dorbie


    Knock yourself out.
  14. dorbie


    I was at a company called Keyhole, we spent most of the day distracted and monitoring the web for news. Within a day we obtained high resolution nadir satellite data of the smouldering crater and the surroundings and added that to our product and I remember spending some considerable time staring at that wreckage. That software is now called Google Earth after an acquisition.
  15. Flaring is not an all or nothing transition. Once you start to flare where you think you should you can ease into it gradually or increase the rate of input based on your judgement. Don't finish your flare early but use your judgement throughout your flare as to your rate of descent & altitude to adjust how much you should flare, and at what rate that should be as you start to plane you out. In other words use your senses to feed back an assessment of how the flare is progressing and adjust accordingly, but don't let up on toggles at any point or you will rapidly lose lift and surge into the ground. As others have said it should be the same height but that requires a consistency you lack and nobody is 100% consistent anyway. It might also help you assess how high you are more consistently by raising your gaze. If you're staring at an approaching patch on the ground instead of perceiving the bigger picture that may be hindering your evaluation of altitude. Note that you can widen your mental perception without necessarily raising your gaze but raising your eyes a bit might also help. Finally my theory craft on landing into wind as it applies to your tale, you do lose some ability to exploit the bottom end flare due to reduced ground speed into wind. You still have that flare in terms of air speed but if you use it you could flare your airspeed to below wind speed and fly backwards and I have a natural tendency to stop as ground speed approaches zero, this is probably the factor influencing you while flaring into wind. To arrest your rate of descent you need enough airspeed above the wind speed to execute the first stage of a two stage flare. If you are not conceptualizing a flare as a 2 stage flare then it is just going to feel like you have tighter margins for your flare which in practice you do. This gets worse if you are in wind high enough as to inhibit even a 1st stage flare, in which case you have a choice of PLF or landing backwards, that's probably not your issue though. Finally, run all this past an real canopy control instructor at your DZ before putting ideas into practice.
  16. This is going to get interesting when the student executes their EPs.
  17. That Toynbee is interesting, and seems to work (but slightly less reliably) with me trying it right now, however the Valsalva is not a case of puffing your mouth/nose into your face to pop your Eustachian tubes. Considerable finesse can be acquired through practice and technique. When using the Valsalva I pinch my nose, fill my mouth with air and adjust the volume of my mouth with my tongue (and other muscles), giving extremely fine control. In pressurizing and adjusting the volume of my mouth I seem to unconsciously seal my mouth from my lungs. This means I am not simply blowing into my middle ears at any time but using delicate mouth control to do just enough to gradually build pressure and open my tubes. The obvious risk with Valsalva is someone over-pressurizing or simply blowing without sufficient control. It is probably best practiced on dry land when you don't need it, incrementally and with care, but without puffing away with your lungs. Try using your facial, mouth & tongue muscles to apply the slightest increments in pressure gradually. Thinking about it my application of the Valsalva technique seems like a hybrid of the Toynbee as the Toynbee swallow is going to seal from your lungs and adjust the volume of your mouth but in a less deliberate manner.
  18. Well done. Others could learn a thing or two from you about attitude. When you start jumping with others there will be plenty of footage.
  19. Sounds like you need some gripper lube.
  20. Sorry, but evidence suggests you are still sharing bogus information and reacting vocally and negatively when called on it. I don't believe many others perceive this is what's going on. What you say gets dismissed because you post nonsense for example about optical distortion being corrected by a sensor crop, then reinforcing your error and claiming victory with marketing literature that's dumbed down for the non expert. yoink's post should have prompted some introspection, sadly it did not. Look it's uncomfortable to admit you've posted some bollocks, but we've all done it. Own it and move on, you'll be better respected.
  21. P.S. I'm not saying you are armchairing this DSE, your experience and generous suggestions have been very helpful, and educational for me. Ultimately though I don't think you can make a one size fits all mount, that's clearer to me now after your input.
  22. Good points, a well designed cutaway would provide sufficient mechanical advantage. In essence it just takes a simple lever from the latch to the cable and there are infinite options. In the event of a mechanical failure it should release. Any design is a compromise, when you start speculating as to what scenarios you might have to cutaway in I return to the basic observation that some cutaway is better than no cutaway and there's a compromise between something your average jumper will mount on their helmets vs. what a more serious camera jumper will or a specialist wingsuiter. I could imagine you putting together a cable routing option where a sleeve routes the cable from the mount to the neck or chin, but that's not for everyone. In fact it'd be a major turnoff for most jumpers who would otherwise benefit from simpler protection. Something like a dual sided cutaway could be preferable to some fancy routing. This is exactly the kind of discussion that screams liability, because you could introduce a mount that could reduce risk, but someone will always be waiting in the wings to armchair skydive it and describe how it could have been better. A simple box that is less snag prone than a go-pro mount is a safety improvement especially when you elect to attach it with nylon screws. Making it detachable is a useful feature but my recent iteration has no cutaway, it is just screw mounted with a rail mounting system that eliminates snag points. Introducing a point of failure using nylon screws as part of the installation would be advisable. Adding a cutaway is an alternative design but doable, adding a cutaway and routing system would be heavily dependent on installation and overall helmet configuration and a separate problem again. It is useful to consider this and how and where a sleeve might be routed to the chin if that is your requirement. But it's not for everyone. I think I might go with my latest option with nylon screw attachments after I work up a release latch mechanism. The rails will take a lot of finishing work if 3D printed using my available tech. I might leave fancy cutaway systems for others to upload here. TBD.
  23. Cool but I don't see how that could conform to a spherical helmet and so would introduce new points of snag at the corners of your mount.