kallend 1,635 #26 June 18, 2003 QuoteBut wouldn't a downwind jump run be moving over the spot too fast. I mean if there's any appreciable wind, the plane's going to have a faster ground speed and people are going to have to really hustle. Isn't it just safer to fly the plane into the wind, slowing the ground speed down and allowing more time for climbouts, etc. ? There's an analysis of this on my web site www.iit.edu/~kallend/skydive/ Click on the powerpoint presentation on separation.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
SkydiveMonkey 0 #27 June 18, 2003 Freefall simulation HERE ____________________ Say no to subliminal messages Quote Share this post Link to post Share on other sites
LouDiamond 1 #28 June 18, 2003 QuoteFreefall simulation HERE you answered your own question. there you have it and in a file format to show to all of the 5 second folks you claim are runing around your DZ. Sounds like a good topic to go over on a weather day."It's just skydiving..additional drama is not required" Some people dream about flying, I live my dream SKYMONKEY PUBLISHING Quote Share this post Link to post Share on other sites
jdhill 0 #29 June 18, 2003 To me it's not so much that FF have higher wingloadings, but that they tend to open higher (at least at my DZ)... FF out last but open first, and say at 3.5K turn toward the landing area and fly under an RW group who is opening at 2.5K... potential disaster... The answer... crosswind jumpruns! No drift problems, no long spots (shouldn't be anyway), no exit order debate because it does not really matter... you still need to give appropriate separation between groups, but its not dependent on winds and jump type, just leave enough room so you don't track into the next group. JoshAll that is necessary for the triumph of evil is that good men do nothing. - Edmund Burke Quote Share this post Link to post Share on other sites
LouDiamond 1 #30 June 18, 2003 QuoteFF out last but open first, and say at 3.5K turn toward the landing area and fly under an RW group who is opening at 2.5K... potential disaster... I don't think I get your point here or maybe you need to word it differently. How does a FF group of people who jump out after the RW people and open higher than the RW people get below the RW people? Logic and physics apply where I jump. Quoteyou still need to give appropriate separation between groups, And if your putting FFs in front of RW groups you had really know what your doing or you will run into problems real quick. There is a very good reason why all the big DZ's do it the same way( RW, FF,Birdmen) because it works, less chance for error and it's easier to manage when there are lots of people in the sky at any given moment. bottom line is that it is the safest way to do things."It's just skydiving..additional drama is not required" Some people dream about flying, I live my dream SKYMONKEY PUBLISHING Quote Share this post Link to post Share on other sites
quade 3 #31 June 18, 2003 QuoteThe answer... crosswind jumpruns! It's an answer, but certainly not the answer. Some drop zones can't accomodate because of ATC issues, so they're usually set up to go either of two directions 180 degrees apart. For instance, at one very popular drop zone in SoCal the regular jumprun is either north to south or vise versa. If the winds are out of the east or west -- it's still the same.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
jdhill 0 #32 June 18, 2003 Jumprun is in to the wind...RW group jumps out first up wind of the landing area... FF out next, further up wind of the landing area... FF group falls faster and opens higher... upon opening flys downwind back to landing area... this path takes the second group (now under canopy) under the first group (still in Freefall)... both logical and physically possible, even where you jump. I am not saying that FF should go in front of RW, am saying the x-wind jump run is a better answer (where possible), and some "big" DZ's use them with no problems.All that is necessary for the triumph of evil is that good men do nothing. - Edmund Burke Quote Share this post Link to post Share on other sites
bbarnhouse 0 #33 June 18, 2003 Oh for chrimeny sakes! Read the attachments. Jump Run Math.doc What you should know about jump run.doc Quote Share this post Link to post Share on other sites
quade 3 #34 June 18, 2003 Well, in Josh's defense, there is more than one way to skin a cat. Hell, I've heard of one drop zone that has used a semi-circular jumprun with pretty good success.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
LouDiamond 1 #35 June 18, 2003 While I consider that highly unlikely to happen, but possible, I would account for human error on the part of the jumpers not using proper seperation between groups and the FF actually opening lower than the RW group. If done properly, the canopies should be stacked up appropriately accross the sky with the first group opening and the following groups opening shortly afterwards for each consequtive group. Ignore seperation times and opening altitudes and all kinds of things can go wrong."It's just skydiving..additional drama is not required" Some people dream about flying, I live my dream SKYMONKEY PUBLISHING Quote Share this post Link to post Share on other sites
bbarnhouse 0 #36 June 18, 2003 QuoteWell, in Josh's defense, there is more than one way to skin a cat. Hell, I've heard of one drop zone that has used a semi-circular jumprun with pretty good success. I am not even going to debate the issue. Seems to me that since your DZ (Quark) and mine follow the same procedures, and my DZ puts out over 180,000 jumps per year it is a system that works well with more than "pretty good" success. Quote Share this post Link to post Share on other sites
jdhill 0 #37 June 18, 2003 I have read the attachements... does not offer anything that I am not aware of, or do not practice... x-wind jumpruns do not change the airspeed or groundspeed of the aircraft, but do change the impact of drift on any given group, all groups will drift downwind, which is neither toward or away from any other group from the same aircraft. Another advantage is that one under canopy, no path back to the landing are is under another group (to include a 180^ second pass). JoshAll that is necessary for the triumph of evil is that good men do nothing. - Edmund Burke Quote Share this post Link to post Share on other sites
jdhill 0 #38 June 18, 2003 I'm not debating, perhaps you're not getting my point... I'm not saying anyone should change the RW, FF, Student type exit order... I'm saying the the type of jumprun makes the exit order more or less of an issue. I have been on x-wind jumpruns at Eloy and Perris (which, according to Q only flie jumprun in one of two directions, leaving the possibility of alot of x-winders), WFFC, and others.All that is necessary for the triumph of evil is that good men do nothing. - Edmund Burke Quote Share this post Link to post Share on other sites
bbarnhouse 0 #39 June 18, 2003 QuoteI'm not debating, perhaps you're not getting my point Oh I got it...like crystal. Quote Share this post Link to post Share on other sites
jerm 0 #40 June 19, 2003 Quote x-wind jumpruns do not change the airspeed or groundspeed of the aircraft, but do change the impact of drift on any given group, all groups will drift downwind, which is neither toward or away from any other group from the same aircraft. Another advantage is that one under canopy, no path back to the landing are is under another group (to include a 180^ second pass). The your argument is not one of exit order, as the title would imply, but one of jumprun direction. Exit order is still an issue for reasons of throw on exit... if the freeflyers will get more throw then the RW groups, i don't want them getting thrown right under the RW groups by getting out before them. Landing without injury is not necessarily evidence that you didn't fuck up... it just means you got away with it this time Quote Share this post Link to post Share on other sites
markbaur 0 #41 June 19, 2003 Quote... if the freeflyers will get more throw then the RW groups, i don't want them getting thrown right under the RW groups by getting out before them. Not to worry. The amount of forward throw is near enough the same for RW and FF that it can usually be ignored when figuring go-to-go times. There are much greater errors caused by mis-estimating ground speed, fast exit counts, and unintended freefall drift. Mark Quote Share this post Link to post Share on other sites
kallend 1,635 #42 June 19, 2003 QuoteFreefall simulation HERE Oooh - nice program!... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
jerm 0 #43 June 19, 2003 Quote Not to worry. The amount of forward throw is near enough the same for RW and FF that it can usually be ignored when figuring go-to-go times. umm.. no it isn't. at least not in relation to putting freefliers out first. between the same types of groups, yes.. both will have similar throw. With RW out first, the difference in throw will help create the desired separation. Flat fliers present when they exit... freefliers cut directly into the wind. Throw is a very big deal. Landing without injury is not necessarily evidence that you didn't fuck up... it just means you got away with it this time Quote Share this post Link to post Share on other sites
