SethInMI

Sounds like you may have read these already, but I will second people who suggested: Elmore Leonard. The master of crime and westerns. Caleb Carr E.L. Doctrow. Billy Bathgate, The waterworks. Larry McMurtry. Lonesome Dove is the classic western. michael chabon. Yiddish Policemans union, Amazing adventures of Kavlier and Clay. Really good writer. I just started reading Alan Furst. Good writer of espionage. Night Soldiers, The Foreign Correspondent. Shorter books, tightly plotted. For non-fiction: Jared Diamond: Guns, Germs, and Steel (pulizer prize). Collapse. Daniel Okrent; Last call. story of prohibition. Avoid Clive Cussler. Avoid Robert Jordan. it takes more than plot to write a story. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Nice 6 year old thread bump! I have decided that safe is too black and white a word for skydiving; too many assumptions get loaded on to it. Is skydiving safe? No. To my mind, you won't get hurt doing a safe activity. Is skydiving unsafe? No. In my mind, an unsafe activity has a high likelihood of death or injury. I don't want to be doing something unsafe. In USPA's defense, skydiving is a lot safer than wuffos think. This is not sport death anymore. The question becomes at what point does an activity transition from safe to unsafe? According to the USPA website the implication I read is that this happened in the late 1990s when the fatality rate per 1000 members got below 1.0. But in the end, it is just a balancing act, single words don't work well. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Warranty? Delivery time? In the thread linked by cpoxon you mentioned you were planning on open/customizable firmware. Is that still the case? If so, can you share what dev kit you are using and any other details about platform. Thanks, seth It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

I will throw my 2c in, on cameras and coaching. When I was a student doing instructional jumps and coach jumps, I really liked the video debrief. I would specifically search out ratings-holders who flew camera to jump with me. I felt at $60-70 a jump, a video debrief and a rip on to my laptop as a souvenir was not too much to ask. So at the time I remember telling myself, when I am coaching, I will video my students. I think if you are going to get paid to coach, it would be something to consider. If you are coach jumping for fun or to pay it forward, well, the student gets what they paid for. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

The crossfires are not cross braced. They have a highly closed nose that does help give them some stiffness, but no crossbracing. They are elliptical, and that is why they need fewer D lines, as the tail tapers in. Rapaz, you have a Crossfire II, with 6 D lines, 3 on each side. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

I forgot the "without an AAD" option! I did that for the 1st time too this year when the Cypres went in for service. One benefit of intentionally skydiving without things is it increases confidence. If you do later get in a "oh shit I forgot my..." moment, at least it won't be anything new. (unless it is a rig). Seth It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Did my 1st few barefoot jumps over the weekend, and now I have jumped without most of the accessories that skydivers normally wear, including all the items listed in the poll. I really like the no-helmet no-goggles H&P. I guess I just like feeling the wind on my face. I didn't like the riser hit I got during one of those style jumps though, so it is a trade-off. Anyone else like a more minimalist type of jump? It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Jesus Christ. It is like Speakers Corner in here, people trying to win points in a argument instead of just working toward clarity and consensus. Robin is saying "if you keep your head on a swivel, you can avoid being forced to make panic turns. Sure you can get hit from behind/above, but you won't ever see that coming, so no panic turn will result." This guarantee, "fly right/head on swivel and no panic turns will be required" does not address HP canopies. Here's a scenario: You are on final in your big boat canpy, correct direction, etc. You hear some whistling sound, look off to the right and suddenly here is Alice the Tool Swooper coming crosswind to low carve a landing. Alice does not see you. It is panic turn time. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

To really push the definition/limits in this "more arm wing"' direction I can think of two ways: 1. Powered/reconfigurable exoskeleton. Jointed robotic arms allow human arms to move freely, but when stopped lock in place to relieve arm muscle fatigue. The pilot is still suspended from the exoskeleton, but he can move it however he wishes. Is that the ultimate wingsuit? 2. Flexible frame. A flexible frame, likely pre-stressed or curved "down" so that when in the air the weight of the pilot flexes it "up" to level. The pilots arms can still bend the frame, but in level flight it takes much of the weight off the arms. The pilot is only partly suspended from the frame. Some one else mentioned the exoskeleton; it makes me think of MechWarrior or some other Japanese anime. They do love their robots in Japan. Seth It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Accelerometers would give better performance, rather than double differentiating position. The nice thing about a sensor like this is the full inertial reference frame (3 accelerometers and 3 gyros). I doubt the quality of either sensor type is good enough for an true inertial solution for any length of time (double integrating accelerometer data requires high quality stuff), but the GPS provides position. The accelerometers and gyros will provide an instantaneous attitude solution, which would be nice to have. This would show you things like: 1. How head low or head high you were at at any point on the jump (was it a steep dive or shallow dive). 2. How fast that flat spin was rotating. 3. What happened on that funky opening. You could see speed, pitch, and rotation of the body during the opening sequence. I don't know how this would work for skydiving. Probably depends on how well the software can take out the gyro bias, and the quality of the gyros and accelerometers. [ramble] Usually the bias is taken out standing still, and for some extreme sports like a short downhill run (skiing, snowboarding, mnt biking etc) this would be easy, stop at the top of the run, zero gyros and get an initial orientation set, then do your run for a few minutes. Skydiving has the whole plane ride thing that would make keeping a known orientation valid more difficult, but if you set a button on jump run that would set a known orientation, it would help. Either way, rotations like flat spins and barrel rolls would be easy to determine, but orientation (pitch, etc) would be harder. Also when traveling at a constant velocity the accelerometers will give some orientation info (basically which direction the ground is), which would be very useful. Blah, blah, blah, Kalman filter, blah, blah, blah. [/ramble] It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

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What you are describing is really a small hang glider and not a wingsuit. Wingsuits generate most lift with the body, not the arms. Is must be this way because we cannot hold ourselves up by the arms; we do not have the massive chest muscles it would take to do it. Adding a rigid frame that passes from wingtip to wingtip would allow the pilot to hang from it and would be the only way to stay in that position for the extended periods you dream of. But I agree with others who say that control of that rigid wing while locked inside of it would be difficult. Hang gliders are suspended underneath the wing and can use that distance to build leverage to control the wing with weight shift (as you know). It would also be a challenge getting a 3-4m wide wing out of an airplane. Some sort of central pivot like the F-14 had would be necessary. Base jumps would probably be the only way to use such a system. With a rigid wing you would lose most what makes wingsuiting wingsuiting, the ability to quickly re-shape your wings, from complete collapse to full flight, to achive the flight mode you wish. Very close proximity flying, including grabbing onto another wingsuiter, would also be lost. I hope someone does develop such a system someday and has success, but I doubt it would replace what we have now. Seth It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

There are no dytters with GPS. However you can get GPS logger, which is about the size of a dytter, but does not have audible tones. Some of the preferred loggers are Wintec WBT-201, QStarz BT-1000, Garmin Foretrex. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

That is awesome. I don't think I can see swooping as hot shit ever again. It is true, "You don't know what you don't know" Never knew hang gliders were ever that small and were flown that aggressively. Fun to see the blending of aero disciplines, Speed hang gliding looks to me more like wingsuiting, as you are flying with the body. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

I know from personal experience that naked jumps in Fremont must land off airport. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

That was the funniest thing I have read in a while. Reading that makes me question the necessity of a long term human occupied moon or mars base. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

I will throw in my own experience, FWIW. I jumped a Triathlon 190 from jump 55-130. Then a Sabre 2 170 from 131-190. Now a Sabre 2 150. I weigh 175lbs, too. I thought the Tri was hard to land in 0 to light winds, it was full flare then a full sprint runout. The Sabre 2 had more flare and could be shutdown better. I had and have a lot of fun doing mini-swoops, 90 front to doubles on both the Sabres. Seth It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

I like this in theory, basically saying if you and your friends can fly your RW/Tracking suits at 2:1, then you can get a WS record. But the problem I see is measuring glide is too hard. GPS is useless without knowledge of the airmass movement, and the alternatives are tools like Yuri's recording bubble-vane-angle detector. You also must address Tracking Derby style comps, where a diving start and plane out is used to improve glide results. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Just in case anyone else does not know, there are two industry giants who have posted in this thread. 1. Bill Booth. Founder/Owner of United Parachute Technologies, the maker of the Vector container. 2. John Sherman. Founder/Owner of Parachute Labs, the maker of the Racer container. Both men have been designing, building and selling parachute equipment longer than I have been alive and I am 37 years old. They both are intelligent engineers and have vast amounts experience. They are also salesmen and long time competitors, so keep that in mind. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Jim (Beatnik): I think you had a good point with the first post you made, that any sales video is not proof of reliability. I have helped make sales videos for my firm that involved multiple takes, so if I as an engineer saw a video for a product we wanted to use, I would not make a reliability judgment based on the video. I think that any analysis of low-speed deployments in this video is of limited usefulness to you and John. There are two issues you are focused on are related to AAD fires: 1. Performance under high speed deployments. 2. Long term reliability/repeatability of said performance. If this is the main concern, I suggest stop over analyzing the low speeds in that video and focus on a way to answer the two issues above. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

John, To the frames question, and math formulas: You missed my point. My point is, the formula you used was not correct for the situation. I think my formula was more correct than yours but it is also not correct for the situation, as both are for freefalling bodies, hence the note about the final velocity being 105mph (after 4.2 seconds). To model the situation correctly, you would need to model the reserve deployment, which would involve drag force calculations, with coeffcient of drag, changing area of the reserve, etc. A method like modified Euler or Runga-Kutta would probably be used. Without a proper math model, it does not matter how much time elapsed, as one cannot convert elapsed time to height lost without a good model. Simple as that, so frame conversions don't matter. On the 29m: I saw several samples with the reserve deployed, that were less than the 300ft limit, so I don't think adding more distance for sample timing is required. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

One piece of information about this list that we need to start to make an informed judgement about container reserve systems is how many AAD fires have happened to each rig type, including rig types without a fatality and so not on the list. If the AAD manufacturers have this data, it would be good to know. If there are many more AAD fires on Vectors and Javelins (because more rigs in service, more jumpers with those rig types with AADs or less alti awareness etc) then the data looks less incriminating. If for some reason there were many more AAD fires on Racers and Mirages, then it would look worse for Vectors and Javs, Wings, Reflexes, and Quasars. But with the failure numbers being thrown around without the success numbers, the engineer in me gets annoyed. Seth It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

John, I read your post, stepped the video through the two low-speed reserve deployments, and don't agree with what you saw. The first deployment does start at 660m, but I see the slider down at 610m, and then the altimeter updates to 589m. I don't know exactly how the alti works, but I fail so see how you can tack on an additional 29m to the 589m value. The second deployment starts at 600m and completes at 571m and then the alti updates to 545m. I also don't agree with your math model. You are using a formula for constant acceleration but this is not a constant acceleration situation. The jumper will initially accelerate due to gravity, but then increasing drag from the deploying canopy will slow him back down. I also don't agree with your math equation. Position displacement under constant accel is d = 1/2at^2 + v0t + d0. Ignoring d0 and using 20fps for v0, and 32fps^2 for accel, you get 368 ft drop in 4.2 seconds. But the velocity is now at + v0 or 155fps or 105mph. This makes no sense. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

If you bought a house last year, technically you are not in the negative. The house is an asset, the mortgage a debt, and the value of the house should be greater than the mortgage. If you bought before the housing crash, you maybe upside down and have a house with a mortgage value greater than the house could sell for, and then you would be in the negative, but sounds like that is not the case. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Your question is not misguided, but your post is in the wrong spot. The moderators will move this to Safety and Training or General. The only new threads here should be reports of actual incidents. You can search the fatality database with the word "tandem" from a link at the top of the incident forum, and that will give you alot of information. In the US, there are usually 1-2 tandem pair fatalities per year. Injuries are different. "Minor" injuries like sprained ankles and broken legs happen a lot. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".