lisamariewillbe 1 #1 October 11, 2005 I know I know, there are tons of threads on this. However, there is so much varience for what people believe that it can get rather confusing. Ive been to DZs where freeflyers go first, and Ive been to ones that put them out last, Ive been told 45 degree angle, then told not to use 45 degree angle. So Im trying to figure this out but not sure where to start. Im looking for what factors contribute to when and how people exit. So far the obvious is How many people exiting and what type of dive flow Wind Type of plane What other factors are important when setting up exit order and delay? I know that at my current level I can not begin to think about setting up when people leave, however I am responsible for myself and want to make sure that I understand the seperation aspects. Ive had a small amount of training reguarding this subject but am wanting others thoughts.Sudsy Fist: i don't think i'd ever say this Sudsy Fist: but you're looking damn sudsydoable in this Quote Share this post Link to post Share on other sites
speedy 0 #2 October 11, 2005 Go to this web page http://www.iit.edu/~kallend/skydive/#resources and click on "Powerpoint presentation on exit safety with freefall sim.(updated 3/2004)" and you find out what you need to know Dave Fallschirmsport Marl Quote Share this post Link to post Share on other sites
kallend 2,026 #3 October 11, 2005 QuoteGo to this web page http://www.iit.edu/~kallend/skydive/#resources and click on "Powerpoint presentation on exit safety with freefall sim.(updated 3/2004)" and you find out what you need to know Oh, what a great resource!... 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
mnealtx 0 #4 October 11, 2005 It *IS* nice work, isn't it? Mike I love you, Shannon and Jim. POPS 9708 , SCR 14706 Quote Share this post Link to post Share on other sites
billvon 2,990 #5 October 11, 2005 >Ive been told 45 degree angle, then told not to use 45 degree angle. Don't use that. It doesn't work. >What other factors are important when setting up exit order and delay? 1. Ground speed. The lower the ground speed the more time you need. This comes from: 1a. Airspeed. Slower airplanes require more time between exits. 1b. Winds aloft. If you're flying into the wind (normal) then higher winds require more time between groups. 2. Group size. Wait longer after a larger group; they will track more and you will need more space to avoid them. 3. Fallrate. Put slower jumpers out first when flying into the wind. 4. Opening altitude. Higher openers can make it back from a far upwind spot more easily so they generally get out later. 5. Special cases. Students generally get out last for several reasons. Skyboarders usually go first because they have to set up in the door. Wingsuits generally go last because they can always get back and the spot really doesn't matter for them. Also lets them see and avoid people's canopies. Quote Share this post Link to post Share on other sites
lisamariewillbe 1 #6 October 11, 2005 Thanks everyone, I have some good places to continue the education. Now I know that the different aircraft have different exit speeds, but dont some jump planes have different ways of flying jump run? I heard that king airs fly a cross wind jump run, and that caravans go into the wind? Is this a factor that should be considered? Once again thanks everyoneSudsy Fist: i don't think i'd ever say this Sudsy Fist: but you're looking damn sudsydoable in this Quote Share this post Link to post Share on other sites
billvon 2,990 #7 October 11, 2005 > but dont some jump planes have different ways of flying jump run? It is not the plane that flies different jump runs, but rather the DZ. Any plane can fly any direction jump run. Some DZ's (like Brown) have to fly a specific direction because of airspace/safety concerns. Some fly crosswind jump runs because then upper winds don't matter as much for exit separation. Quote Share this post Link to post Share on other sites
lisamariewillbe 1 #8 October 11, 2005 Okay I see , its more specfic depending on the DZ, okay so how do ground winds affect ? I understand the uppers and why they do , and understand how they correlate to horizontal seperation, so does the ground winds play into the exit? Sorry if I am asking to much. Thanks for the help ya'allSudsy Fist: i don't think i'd ever say this Sudsy Fist: but you're looking damn sudsydoable in this Quote Share this post Link to post Share on other sites
mnealtx 0 #9 October 11, 2005 QuoteOkay I see , its more specfic depending on the DZ, okay so how do ground winds affect ? I understand the uppers and why they do , and understand how they correlate to horizontal seperation, so does the ground winds play into the exit? Sorry if I am asking to much. Thanks for the help ya'all You have to plan your opening point in relation to the lower winds. Put your opening point too far out and the winds may have you landing off. This was MUCH more critical in the days of round mains, or square mains/round reserves. I can recall my old instructor saying "you always spot for the reserve"...Mike I love you, Shannon and Jim. POPS 9708 , SCR 14706 Quote Share this post Link to post Share on other sites
billvon 2,990 #10 October 11, 2005 > does the ground winds play into the exit? Sort of. What you really care about is the aircraft ground speed and the speed of the winds at opening altitude. The distance you will get between group centers is the speed of the aircraft plus the speed of the winds at opening altitude, multiplied by the time you leave between groups. So if the aircraft is flying into the wind doing 80 knots per its GPS, and the winds at opening altitude are 10 knots from the same direction, and you are waiting 10 seconds between groups, you are going to get (80+10 = 90 kts, which is 153 feet per second) 1530 feet between groups. Since winds at opening altitude are generally much lower, you can usually ignore them and just use aircraft speed. So in the same example above, if you just looked at aircraft speed, you'd get 1360 feet, which is 80 kts (136 feet per second) times ten seconds. Any winds at opening altitude will just give you a little more separation. The one time you DO have to worry is if the winds are from the opposite direction at opening altitude. Then you have to leave even more time between groups. This can happen during Santa Ana winds in California for example, where uppers might be out of the east at 50kts but at 3000 feet winds are out of the NW at 10 kts. That's a dangerous scenario and you have to leave a LOT of time between groups. If all that math scares you, don't worry. Generally all you have to know is to leave more time when the upper winds are high. If you have a close call, leave even more time. Note in all this I have not discussed spotting, which is picking an exit point for the first group so that everyone makes it back. That's a separate discussion, one that has a lot to do with _surface_ winds. Quote Share this post Link to post Share on other sites
lisamariewillbe 1 #11 October 11, 2005 Okay so is there a "standard" suggested vertical seperation for opening? Im learning things on spotting as well... however I just thought this would be a good thing to start with, as I understand spotting and such in regards to the wind forecast much better then I understand the exit order. Whats really great on the spotting is this guy Mark at the farm, he will spot even with GPS and he tells you why we get out where we do according to what the winds are doing at varies alti's. Ill save those ?s for later.Sudsy Fist: i don't think i'd ever say this Sudsy Fist: but you're looking damn sudsydoable in this Quote Share this post Link to post Share on other sites
billvon 2,990 #12 October 11, 2005 >Okay so is there a "standard" suggested vertical seperation for >opening? You mean group #1 should open at 2000 feet, group #2 at 2500? No. It doesn't help much; there's just too much variation in altimeters, breakoffs, and snivel distances. About the only time it matters is if someone is going to pull _really_ high, say 2000 feet higher than the previous group. Then they generally get out afterwards. But keep in mind that a hard pull could put him right at the same altitude as the previous group, so you still need that horizontal separation. Quote Share this post Link to post Share on other sites
lisamariewillbe 1 #13 October 11, 2005 So then we would need to consider cutaways also right? Since this will put a person in freefall longer.Sudsy Fist: i don't think i'd ever say this Sudsy Fist: but you're looking damn sudsydoable in this Quote Share this post Link to post Share on other sites
billvon 2,990 #14 October 11, 2005 >So then we would need to consider cutaways also right? Definitely. Which is why horizontal separation is always important. Quote Share this post Link to post Share on other sites
lisamariewillbe 1 #15 October 11, 2005 So if there isnt a instructor or not many experienced people on a load, is it safe and okay if we give a extra few seconds from what the group states? ie someone with 100 jumps asks me to give them a 5 sec delay, but I want to take 7 ?Sudsy Fist: i don't think i'd ever say this Sudsy Fist: but you're looking damn sudsydoable in this Quote Share this post Link to post Share on other sites
billvon 2,990 #16 October 11, 2005 > ie someone with 100 jumps asks me to give them a 5 sec delay, > but I want to take 7 ? Leaving more time is almost never a dangerous thing to do, unless that means you will land out. The groups behind you may complain, but remember that your safety is up to you, and if you feel you need more time then take it. More separation is, in general, better than less. Quote Share this post Link to post Share on other sites
lisamariewillbe 1 #17 October 11, 2005 okay, thanks again all who sent pms or posted here, it definitley gives me a bit more insight... Is there any important things I am forgetting?Sudsy Fist: i don't think i'd ever say this Sudsy Fist: but you're looking damn sudsydoable in this Quote Share this post Link to post Share on other sites
LouDiamond 1 #18 October 11, 2005 Here is a chart to better understand what Bill stated about time between groups and ground speeds. Some DZ's post this right by the door/lights so that jumpers can see what the correct time between groups is. It does require the pilot to pass the ground speed to you when on jump run for it to work correctly."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
billvon 2,990 #19 October 11, 2005 Good chart. I would also add that .2 miles (~1000 feet) is a good minimum separation for small (up to 6) RW groups. The .3 mile column is good for larger groups (say, up to 12.) Quote Share this post Link to post Share on other sites
bigbearfng 18 #20 October 11, 2005 Also, please don't succumb to the pressure of anyone yelling for you to hurry up and go.....yes I did it-but only once! And before anyone here hollers about "don't take too much time in the door because you hose the rest of the groups"-ya, keep it reasonable. Quote Share this post Link to post Share on other sites
lisamariewillbe 1 #21 October 11, 2005 I cant get the chart to show... I try saving it and it doesnt allow me to. Ive yet to feel like I was hurried at the door, I guess I am lucky with where I jump, safety is such a high concern. Posting this is just me wanting to know more of the who whys and hows if this sport.Sudsy Fist: i don't think i'd ever say this Sudsy Fist: but you're looking damn sudsydoable in this Quote Share this post Link to post Share on other sites
BIGUN 1,297 #22 October 11, 2005 QuoteHere is a chart to better understand what Bill stated about time between groups and ground speeds. Some DZ's post this right by the door/lights so that jumpers can see what the correct time between groups is. It does require the pilot to pass the ground speed to you when on jump run for it to work correctly. What a great chart. Folks have been stating ground speed as the predicating factor for a long time, but no one has pressed the issue of the pilot communicating the ground speeds to the back of the aircraft to determine time. This tool should be used as much as Kallend's info. Thank you.Nobody has time to listen; because they're desperately chasing the need of being heard. Quote Share this post Link to post Share on other sites
perse 0 #23 October 11, 2005 (Moderator's note - please read the post below this one BEFORE replying!) Quote> So if the aircraft is flying into the wind doing 80 knots per its GPS, and the winds at opening altitude are 10 knots from the same direction, and you are waiting 10 seconds between groups, you are going to get (80+10 = 90 kts, which is 153 feet per second) 1530 feet between groups. Why do you think that the windspeed (or direction of the plane) would affect the horizontal distance between groups???!! The plane is flying in airmass that is moving to some direction with a certain speed. the jumpers exiting the plane will be "flying" in the same moving airmass, and the horinzontal distance to the other jumpers is only affected by the planes airspeed. What is wrong in your calculation is that you forget that all the jumpers are flying in the same moving(relatively to the ground=wind) air than the plane. There will be a little difference whether the plane is flying into the wind or for to the opposite direction, but that will only be if some jumpers have longer freefalls than the others and there's a different wind in different layers on the way down. This difference will anyhow be so small that it really makes no difference. Please don't "teach" before you find out how things really are... Quote Share this post Link to post Share on other sites
perse 0 #24 October 11, 2005 ...sorry. Just noticed that the speed (80knots) is measured with GPS. YOU´RE RIGHT TOO. (I just have never had chance to jump from a plane with GPS available to jumpers..., airspeed is what you usually know...) Quote Share this post Link to post Share on other sites
lisamariewillbe 1 #25 October 12, 2005 Okay so this may be totally off the wall. However given the information in this thread and the min speed of fall rate... would there ever be a case where 8 seconds was not enough seperation? I played with different wind speeds (except the santa ana type ones) and in every instence found out that depending on dive flows, that 8 secs seemed to be enough. Is it bad to start this way of thinking?Sudsy Fist: i don't think i'd ever say this Sudsy Fist: but you're looking damn sudsydoable in this Quote Share this post Link to post Share on other sites