SethInMI

As a general rule you don't want to transport bugs from one continent to another. That is why I would have killed it. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Ke = 0.5 m v^2 is what you are thinking of. That is the kinetic energy equation, not the force equation. Another important equation for this is the drag equation, Fd = Cv^2, which means that the drag force is proportional to the the square of the velocity * C, where C is determined from drag coefficent and area. Peak force calculation is complicated because the parachute deploys over a period of time with slowly increasing area. The kinetic energy of motion is dissipated over this interval. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

I remember this threadhttp://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=post_view_flat;post=2326601;page=1;sb=post_latest_reply;so=ASC;mh=50; That thread started with a jumper overloading a reserve and got into a big technical discussion about weight and deployment speeds and forces involved. One poster (Sparky or Jerry B) posted a chart of some test data, some of which is: NAB Data 5000lb test Weight(lb) Speed(mph) 660 150 500 175 400 200 325 225 275 250 225 275 200 300 175 325 160 350 150 375 3000lb test 750 100 525 125 375 150 300 175 235 200 200 225 The tests say that deploying 660lbs at 150mph produces the same peak force as deploying 150 lbs at 350mph (5000lbs). So I would say velocity is a bigger factor. I created and posted in that thread several spreadsheets that modeled a parachute deployment that agreed pretty well with test data, so if you are curious beyond just a yes or no answer track it down. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Hmm. Well if that shape is correct, and the span and chord for a Pulse 120 are correct in the PD website, then a Pulse 120 would actually have a little less than 120 sq ft of surface area. I think the picture i created is still valid, basically showing how the span and chord for a Katana varies from a Pulse by being "fatter" and "longer" but coming out with roughly the same square footage. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

That article by John LeBlanc was a great read. He basically has a whole canopy course in that 13 pages. I was inspired to do a comparison of two canopies, a Pulse and a Katana from data on PD's website. Using a cad program, I created shapes from the chord (length) and span (width) off the website for the both canopies, and while holding the span and chord (for the Katana both chord measurements) to the published numbers, I adjusted both shapes until the cad program said they were 120 sq ft in area. I barely had to tweak the Pulse shape. Pulse 120 Chord: 6.81ft Span : 17.65ft Katana 120 Chord:7.14/4.86ft Span: 18.13ft So you can see from the numbers above and the pic that the Katana is longer and fatter for the exact same square footage. I always had this idea that ellipticals were both longer and skinnier that squares, but that is not the case. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Well, I have Javelin J3 with a PD176R. I bought it 2nd hand 3 years ago, and it has had that reserve in it since it was built in 1998. If it is a bad idea, I would like to know. It was repacked at the factory last spring with no comment. Seth It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

On www.trackingderby.com you can see GPS tracks of trackers, both wingsuit and "regular" suit. By viewing individual performances, you can see the ground speed, vertical speeds, etc. Don't know if they had a tailwind of course, but the ground speeds for the records are 150mph+. For a typical good track? I don't know. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

I like credit unions, I have been a member of Navy Federal Credit Union since I was a kid, and there Flagship Rewards Visa one of the best rewards programs (IMHO), but I like the fee forgiveness that USAA has and I am trying to replicate that. It is soooo nice to realize you need cash and not have to look for a specific ATM or brand of ATM. Just be able to go to any ATM and not have to pay a fee. And I mean anywhere, I used it in Europe and Asia too. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Right, I wanted separate passwords and usernames that cannot access the other accounts I have, with a separate bill pay setup for separate bills. I don't think they can do that, but I should ask them again. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

I looked a little bit at ING, Everbank, and e-trade. I am primarly interested in no-hassle money access with this account, as I will not have a lot of money in it. ING appeared to only allow ATM access at certain ATMs (although these were plentiful, you had to do an internet search to find them, and most were in stores so no drive up access) and Everbank offered ATM fee reimbursements, but you had to send in the receipts in the supplied envelopes, which seemed like a pain in the ass. Thanks for the suggestions, I will check out the others. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

I use USAA now, and they are great but I want to start a new joint account and it is best kept totally separate, i.e. a separate bank. USAA internet banking offers several features I like: 1. Up to $15 a month in ATM fee automatic reimbursement. You can use any ATM to get cash, they pay the fee, so it is like any ATM is "your" ATM. 2. Free business reply mail-in deposit envelopes, so you can deposit checks for free. 3. Good free online bill pay. 4. No monthly fees, no minimum balance. Downside is very low interest, about 0.1% APY. Anyone else have a bank setup similar to this that they like and recommend? Thanks, Seth It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

The AFLAC supplemental insurance I was offered at work excluded non-airline aviation related claims. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

I think bfilarsky has it right, and you are wrong here. You forget about drift under canopy. To continue your example of a 90knot plane in a 90 knot headwind that continues down to opening alt, the plane may not be moving w/respect to the ground, but it will be moving w/respect to the jumpers that have opened, as they will be in a 90knot breeze. Just a few sec of delay between groups will be fine, and no one will have to worry about opening on top of eachother. As John said, this case of constant winds at all altitudes is not a real world case, but I think it useful to show that one understands what the actual mechanics are. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

You are also (mostly) correct. I only addressed the question the OP was asking about a specific variable, wind speed, not about group size or flying technique (FS vs FF). It is true that if the wind speed is constant w/altitude then it doesn't matter what it is, the only determinant is airplane airspeed. My edited post including billvon's statement is all you need to see this is the case. Airplane groundspeed is just Airplane Airspeed - Winds at Exit Altitude. If winds at exit = winds at opening, they cancel out, and the only variable left is airplane airspeed. However, that is a very special case, and billvons statement covers all cases, as it takes in the three important variables, Airplane Airspeed, winds at Exit, and winds at opening. I think that is all the OP wanted answered. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

You are correct on both statements. 1. The basic assumption is that winds will decrease with decreasing altitude. 2. If the winds were constant from exit to opening, then wind speed would not matter. This has been discussed here a lot; billvon put it really succinctly in another thread: "Distance between groups will be given by aircraft ground speed plus wind speed at opening altitude, times seconds between groups." And a plug for my freefall simulator: FreeFall 3D Thread It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Nice work by the dutchman. My web skills are 0, so I am stuck with an "offline" solution. Nevertheless, I updated the free fall simulator I wrote to calculate the spot. By adjusting the canopy descent rate you can adjust the spot. The default descent rate is 6mph like a canopy w/toggles stowed. If multiple groups are out the spot will be adjusted so that touchdown points of the farthest groups will be equidistant from the landing zone. Free Fall Simulator for Google Earth It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

This is a bit of deja-vu for me. I was probably on my 10-15th jump on my 1st rig when I found the same problem with my kill line while packing my 2nd jump of the day. Someone at the DZ gave me a rapide link and helped me hook it up and I kept jumping. I still don't know how the link that was there disappeared. I am sure it was there, I got the rig used with the bag hooked up, had a rigger help me hook it up to my 1st canopy, jumped it quite a few times, and yet it was gone when I landed from a jump. I can only assume it was loose and worked its way off and I never noticed it working its way off. I still remember looking at the bridle just like in your pic and trying to figure out what the hell was wrong. Seth It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

I will also attach the kmz file that created the screen shots, so if you want to look at the output without running the program, download the kmz file and open in Google Earth. Ok, not quite the same, I could not include the airplane as it would push the file over the 300KB attachment limit, so this kmz only has a red line for the plane track. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Marks: I don't know, it looks like the program does not have access rights to open the dropzones.xml file in the Program Files directory. Not sure why. You could try to browse to that folder and try to open the file with a text editor and see if that works. All (incl marks): You must install Google Earth to see the tracks. Google Earth can be found at http://earth.google.com It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

I wrote a FreeFall 3D Simulator for Google Earth, based on earlier work by John Kallend and Dave Blumenthal. An install program can be downloaded here: http://twinoak.altelco.net/~sdcooper/FreeFall3D/SetupFreeFallSimulator.msi If you want to skip the install, download the program and support files here: http://twinoak.altelco.net/~sdcooper/FreeFall3D/FreeFall3D.zip And then optionally some airplane models from Google Warehouse http://twinoak.altelco.net/~sdcooper/FreeFall3D/Models.zip Then unzip to a folder and run. Attached are some Google Earth screenshots and the readme file. If you try it and have a problem, let me know. There is very little error checking! For the techies, the program is .Net (C#) requiring the 3.5 Framework (windows only, although I would like to try it with Mono on Linux). I am GPLing the program, so if you want to screw around with it, let me know. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

After a few years of some 5ks and 10ks, I am entering my 1st 25k this May. I am telling everyone I am going to do it, b/c then I cannot back out. However, I have not registered yet... 25k sounds intimidating, but I look at the recommended training schedule and it seems more doable. Just a little farther each week, no problem right? It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

That explains the grass. I recognized the buildings and tents as Perris, but could not explain the grass. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Perris, CA. That belly camera is b-i-g. http://www.3dcameracompany.com/index.php?option=com_content&view=article&id=52:will-digital-cinema-carry-3d-to-new-glory&catid=1:3dcc-news&Itemid=6 Another link to a news story on the same website by the canadian society of cinematographers, shows John DeVore with the belly camera. The camera pic caption reads: "Sky grip Claude Fortine rigging on Arri 235 system on Jon DeVare of the Red Bull Skydive Team in preparation for a jump in Human Flight 3D. The red hand under his chin is to jettison the entire camera system by parachute landing." Since they misspelled John's name, I assume the comment about the "red hand[le] under the chin" is actually to jettison the camera without a parachute landing. Can anyone comment on the setup in that pic? It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

Yeah, you can do a lot of funky exits from a Cessna, good fun. If there is only one slot on a Cessna load, I often do a H&P. Take it to terminal or pull as soon as you are stable, and have the sky to yourself. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

According a poster in the thread in the elections forum, the reason for getting a USPA waiver (and implied sanctioning) was because the FAA told them to get it. I suppose the FAA's reasoning was "we don't know if this is a good idea or not. The USPA knows parachuting, so if they say it is ok, then it is ok with us" If that is the case, the Red Bull team is stuck either trying to get the FAA to go back on its USPA waiver request or trying to get the USPA waiver. It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".