magicmx5 0 #26 January 9, 2002 agreed. It's always in your hands to not get out of the plane if you don't feel safeIf you're not having fun, what's the point Quote Share this post Link to post Share on other sites
billvon 3,059 #27 January 9, 2002 >agreed. It's always in your hands to not get out of the plane if you don't feel safeYes, and you can always determine your separation to the group that got out before you. It's the group behind me that I always worry about. I can't count the number of times I've had someone open near me, who then said "Oh, we gave you a good eight or nine seconds" when questioned.I remember one year at Quincy when we had the worst possible conditions - into the wind at jump run, but 180 degree wind change by opening altitude. I must have been on the PA five times that day, telling people to leave 10-15 seconds between groups. Of course, few people did it because a) 10 seconds is really long and b) everyone else on the plane was shouting "GO!" at them.-bill von Quote Share this post Link to post Share on other sites
dove 0 #28 January 9, 2002 Yes Bill! That's it exactly! Thank you! You dicsuss that separation is like 8 seconds and then as you're counting people are SCREAMING! I once saw a guy ask the group before him how long they wanted and they said 6 seconds. He counted out loud to 6 and jumped. Problem was he counted to 6 in about 2 seconds! Very frightening! dove Quote Share this post Link to post Share on other sites
diverdriver 6 #29 January 9, 2002 Groundpseed 100 knots or greater = 5 seconds between exitsGroundspeed 90- 100 = 8 seconds between exitsGroundspeed 80-89 = 12 seconds between exitsGroundspeed 70-79 = 15 seconds between exitsGroundspeed 50-69 = 20 seconds between exitsGroundspeed less than 50 should have at least 25-40 seconds between exits.The lowest groundspeed I saw in the Otter was 17 knots. We were doing 45 seconds to 50 seconds between groups. That was truly funky. The highest groundspeed I've seen in the Otter was 155 knots. Plus we were doing a world record climbout which took 35 seconds from green light to actual launch. That took a little convincing to get them to go on the green light. It didn't matter where we were over the ground as long as I knew where they wanted to exit. The GPS would count it down to exit point. Worked like a charm. That little GPS also gave me the ability to announce over the PA what the seperation should be using that table. The only problem I ever had would be that people would count to that number and then start their climbout. Which when you're over 100 knots across the ground hoses everyone behind the second group usually. But I digress from the original thread here.Chris SchindlerD-19012ATP/CFIIwww.DiverDriver.com Quote Share this post Link to post Share on other sites
billvon 3,059 #30 January 9, 2002 >The GPS would count it down to exit point. Worked like a charm. Ah yes. The GPS spot. One of my first experiences with a GPS spot on a formation load was years ago during my first Arizona record attempt. We were in the C123, with two otters in trail. Larry was in the "boss seat" in the cockpit, looking over both the pilots and the cargo bay where 50 or so of us milled around.We turned on jump run, the pilot lined up the spot - and the GPS stopped working. Larry started yelling for someone to spot, but since the C123BK is just about the loudest plane in the world (big radials AND zero bypass jet engines) it was a futile exercise. The pilots considered taking it around and using one of the Otter's GPS's, but Larry did a quick calculation as to how much it would cost to take the whole fleet around again and said "Just drop em."We exited about eight miles from the DZ. I couldn't even see it in the distance. We landed in the desert and walked to the nearest road. It was eerie seeing 80 plus skydivers all just walking down the road, in the direction (we hoped) of the DZ. Finally one van came, and there was a mighty battle to see who would get in it. We all made it back about half an hour later once they pressed the buses into service.Usually GPS spots work great - but when they're off, they can be _really_ off. Then there was that time we were in Mexico with MTV sports doing a demo onto a beach. The pilot was given GPS coordinates to punch in, coordinates that had been taken carefully the previous day with a handheld GPS. The coordinates ended up being in Arizona, but fortunately the pilot noticed before we started an 800 mile long jump run.-bill von Quote Share this post Link to post Share on other sites
weid14 0 #31 January 9, 2002 so with a 90 knot IAS, and 30 knot uppers, you leave how long between groups? anyone, anyone, beuller?? Quote Share this post Link to post Share on other sites
diverdriver 6 #32 January 9, 2002 Quotethe pilot noticed before we started an 800 mile long jump run. Bahahahaha....LOL...Been there. Yah, GPS is a tool. Tools break. But a good craftsman never blames his tools. I think my grandpappy told me that.Chris SchindlerD-19012ATP/CFIIwww.DiverDriver.com Quote Share this post Link to post Share on other sites
diverdriver 6 #33 January 10, 2002 Ok, remember you have to figure first: what altitude are you at. Just because you indicate 90 doesn't mean you're doing 90 knots. Huh? It's call KTAS (Knots TRUE Airspeed) and it has to do with Density Altitude. Huh? Basically an Otter on jumprun at 13K indicating 80 knots (what I fly) will have a true airspeed of about 100-105 knots. If there is no wind then that's what you're doing across the ground. Now, your 30 knot uppers. Are they on the nose? Crosswind jumprun will produce a different groundspeed. So don't get too hung up on doing the mental calculation on the ground. Just ask the pilot what the groundspeed is off the GPS and you can go by the table. But....answering your question....30 knots on the nose would have a ground speed of ABOUT 75 knots. Does that help?Chris SchindlerD-19012ATP/CFIIwww.DiverDriver.com Quote Share this post Link to post Share on other sites
billvon 3,059 #34 January 10, 2002 >so with a 90 knot IAS, and 30 knot uppers, you leave how long between groups? anyone, anyone, beuller??Well, I actually do the math, but I'm a nerd, so . . .Very roughly, one knot is about 1.5 feet per second. 90kts IAS into a 30kt wind gives you about 70kts groundspeed, or about 105 feet per second. Waiting 5 seconds will give you 500 feet separation, which is too small for anything other than solos who are going to fall straight down. 10 seconds gives you 1000 feet, which is a good separation for 4-6 way. The conversion factor above errs on the side of caution, so you'll actually get a little more than this. In addition, this is really only valid for a "typical" day where uppers are strong and winds at opening altitude are not.Note that most 4-way teams take 6-8 seconds climbing out and doing the count, so you are generally OK with 4 ways going with a few seconds between previous group and next group climbout.-bill von Quote Share this post Link to post Share on other sites
billvon 3,059 #35 January 10, 2002 >Bahahahaha....LOL...Been there. Yah, GPS is a tool. Tools break. But a good> craftsman never blames his tools. I think my grandpappy told me that.Yep. And a skydiver should never blame the GPS for a bad spot - he should just blame the pilot. (ooohhh . . .)-bill von Quote Share this post Link to post Share on other sites
billvon 3,059 #36 January 10, 2002 >Yes Bill! That's it exactly! Thank you! You dicsuss that separation is like 8 >seconds and then as you're counting people are SCREAMING! I used to try to explain what I was doing and how long I was waiting, but yelling jumpers seem to just keep yelling when you do that. Ignoring them, or giving them the finger if they get obnoxious, seems to work better. Once, after a Quincy otter load, someone came by to tell me that green meant go even if we were the second group! He got snotty about it and I said something like "If you think that I'm going to take my group out of the plane before I think it's safe because _you_ want a better spot, you're crazy." He went off saying that I should learn something about separation. I was sort of hoping that he would complain to manifest, just to get the issue more out in the open.>I once saw a guy ask the group before him how long they wanted and they said >6 seconds. He counted out loud to 6 and jumped. Problem was he counted to >6 in about 2 seconds! Very frightening! Yep. Too often, we get enough separation just because it takes more than 4 seconds to climb out, count and go. That, and the fact that the sky is big and we're small, means that we get away with it pretty often - but it just takes one freefall/canopy collision to really ruin your day.-bill von Quote Share this post Link to post Share on other sites
weid14 0 #37 January 10, 2002 I was seeing if anyone else would venture a guess, I thought about doing a poll, but was to lazy Quote Share this post Link to post Share on other sites skreamer 1 #38 January 10, 2002 Bill, what would you do if the uppers were changing constantly (direction and speed)? At my DZ we occasionally get put on a hold at '6 000 and by the time we are on jump run it might have been half an hour since we took off (plus we always do two passes). Would you check with the pilot (if possible) to work out ground speed and time between exits? Also, what if the JM sucks at maths - how is he supposed to work out exit order at short order? (experience?) WillPS what does the "I" in IAS stand for? Quote Share this post Link to post Share on other sites PhreeZone 20 #39 January 10, 2002 IAS= Indicated Air SpeedI want to touch the sky, I want to fly so high ~ Sonique Quote Share this post Link to post Share on other sites 3fLiEr 0 #40 January 10, 2002 Skreamer - Remind me to bin myself off the lift if you ever get to jump master it!!.............why not just do the 45 angle?....... its easier!...... also you can see the ground speed as your looking at the spot..... judgement can then be made on whether a long or short delay between exits...........So when are you going to get off your arse and learn to spot......... coz I hate being jumpmaster and would love you to rather than me on lifts!!!........ bsbd"In a world where we are slaves to gravity I am pleased to be a freedom fighter" Quote Share this post Link to post Share on other sites PhreeZone 20 #41 January 10, 2002 45 degree angle does not insure any thing. all that it does is say they have fallen the same distance down as the plane has traveled out. Unless you are giving them 7 seconds, you will end up right on top of the other group with any drift or sliding.I want to touch the sky, I want to fly so high ~ Sonique Quote Share this post Link to post Share on other sites 3fLiEr 0 #42 January 10, 2002 Surely with a strong head wind the drift on the group and the time it takes for the plane to travel enough distance to get the 45 angle your drift then will be parallel to the previous groups drift and thus you will not go over the top............ or maybe I just speak complete bollox??!?!?bsbd"In a world where we are slaves to gravity I am pleased to be a freedom fighter" Quote Share this post Link to post Share on other sites diverdriver 6 #43 January 10, 2002 Replying to No Ones post in general......but......Ok, this thread has totally fallen into freefall drift now but I'll continue.....If the average windspeed during freefall is 60 knots then you will drift about 1 nautical mile during freefall. That "45 degree angle" will be achieved fairly quickly since the jumpers are now in drift. It DOES NOT MEAN YOU HAVE GONE ANYWHERE. You have to look at horizontal seperation and the only way to achieve that is RxT=D. Rate over the ground times Time equals Distance seperated horizontally. Now, just print out the table I posted, ask the pilot what the current (actual) groundspeed is on that load on short final for jumprun and figure it from there. It's just as hard to teach someone to truely look STRAIGHT DOWN as it is to teach them to judge a fourty five degree angle. And I believe it's harder than people make it out to be when we're flying crosswind jumpruns. People think the nose of the planes always points to where you're going and that's not the case. At least if they're counting out loud others on the load can slow them down if they are counting too fast. Or at least try to.In this whole debate we have been looking for the simplest ways which will almost always produce the widest safety margine on exits. Flat flyers before Free Flyers will always work unless you are going downwind. If you are doing downwind jumpruns the operation should be smart enough to make the change. So load the plane that way. Counting out seperation is the easiest way once the groundpseed is known to get proper seperation. No 45 degree estimation. No eyeballing the groundspeed (what if I give extra altitude? The angle change will be different and it will look like we're going slower. You can eyeball that change? You are more manly than I.)All of us here have the same goal in mind. Skydiving Safety. That is the key to this whole thread and am glad to see all the thoughtful posting.Quincy? Shit, you've got the whole county to land in and someone will give you a ride back. But here's a concept: look down during freefall and pull a little higher. Whooow! It is too bad that guy didn't go to manifest and complain. I would have liked to be on that one. Most people have no concept of real seperation. I here it all the time and just shake my head. "Well, that's the seperation we were using yesterday and it worked." That's like landing downwind saying "Well, that's the direction I landed yesterday." ;-)Chris SchindlerD-19012ATP/CFIIwww.DiverDriver.com Quote Share this post Link to post Share on other sites skreamer 1 #44 January 10, 2002 QuoteSkreamer - Remind me to bin myself off the lift if you ever get to jump master it!!.............Thats what everybody who was on that Cessna load I JM'd last Saturday is now saying too... (but apart from my short spot, my crap canopy control and my loss of altitude awareness everything else went ok.... it was not my best skydiving day) Quote Share this post Link to post Share on other sites 3fLiEr 0 #45 January 10, 2002 "my loss of altitude awareness"& YOU DID NOT GET GROUNDED!!!..... SPAWNY BASTARD!!!!BSBD"In a world where we are slaves to gravity I am pleased to be a freedom fighter" Quote Share this post Link to post Share on other sites billvon 3,059 #46 January 10, 2002 >Bill, what would you do if the uppers were changing constantly (direction and> speed)? At my DZ we occasionally get put on a hold at '6 000 and by the time> we are on jump run it might have been half an hour since we took off (plus we >always do two passes). Back when I was flying a lot I would get an upper-winds forecast and fly 2-3 hours later. They weren't always right, but they were never 180 degrees (or even 90 degrees) off. Unless you have some serious weather moving in, the upper winds shouldn't change much over the course of an hour.>Would you check with the pilot (if possible) to work out ground speed and time between exits? If you had time. GPS vs. airspeed is the most reliable way to tell what the uppers are. If you have GPS, though, all you really need to know is your groundspeed. If it's low, wait longer.>Also, what if the JM sucks at maths - how is he supposed to work out exit order at short order? (experience?) I hope so! As far as I can tell, no one but me does math on jump run. They just get used to high winds = 15 seconds.-bill von Quote Share this post Link to post Share on other sites billvon 3,059 #47 January 10, 2002 >It's just as hard to teach someone to truely look STRAIGHT DOWN as it is to >teach them to judge a fourty five degree angle. I agree, especially since no one has to spot any more. It's the hardest skill to learn in spotting, partly (I think) because it sounds so easy.>No eyeballing the groundspeed (what if I give extra altitude? The angle change> will be different and it will look like we're going slower. You can eyeball that> change? You are more manly than I.)I disagree here. Even if you can't eyeball the angle, you can eyeball the ground and get a feel for distance traveled. Line anything in the plane up on a known point on the ground, and wait until that line of sight hits something 1000 feet away, and you will have travelled 1000 feet over the ground. This is the "skratch" method of ensuring exit separation, and I think it works pretty well - as long as there are landmarks you can use to judge distances fairly accurately.>Quincy? Shit, you've got the whole county to land in and someone will give you a> ride back. But here's a concept: look down during freefall and pull a little higher. Whooow!While I agree in concept, I would never tell anyone at Quincy to pull higher. There have been too many close calls from the next load opening all around someone who pulled "a little high."-bill von Quote Share this post Link to post Share on other sites freeflir29 0 #48 January 10, 2002 "While I agree in concept, I would never tell anyone at Quincy to pull higher"Plus...I hate ruining my skydive by having to pull hi....."I got some beers....Let's Drink em!!!"Clay Quote Share this post Link to post Share on other sites weid14 0 #49 January 10, 2002 the 45 degree angle thing doesn't always work -- what angle of attack the plane is on, and you neck calibration has much variability. Quote Share this post Link to post Share on other sites diverdriver 6 #50 January 10, 2002 QuoteWhile I agree in concept, I would never tell anyone at Quincy to pull higher. There have been too many close calls from the next load opening all around someone who pulled "a little high."Sorry, it was a relative statement. The window is 2,000 to 3,000 for opening right? I was refering to the 3,000 side of pulling. Yep, eating somone else's canopy does suck.Chris SchindlerD-19012ATP/CFIIwww.DiverDriver.com Quote Share this post Link to post Share on other sites Prev 1 2 3 Next Page 2 of 3 Join the conversation You can post now and register later. If you have an account, sign in now to post with your account. Note: Your post will require moderator approval before it will be visible. Reply to this topic... × Pasted as rich text. Paste as plain text instead Only 75 emoji are allowed. × Your link has been automatically embedded. Display as a link instead × Your previous content has been restored. Clear editor × You cannot paste images directly. Upload or insert images from URL. Insert image from URL × Desktop Tablet Phone Submit Reply 0
skreamer 1 #38 January 10, 2002 Bill, what would you do if the uppers were changing constantly (direction and speed)? At my DZ we occasionally get put on a hold at '6 000 and by the time we are on jump run it might have been half an hour since we took off (plus we always do two passes). Would you check with the pilot (if possible) to work out ground speed and time between exits? Also, what if the JM sucks at maths - how is he supposed to work out exit order at short order? (experience?) WillPS what does the "I" in IAS stand for? Quote Share this post Link to post Share on other sites
PhreeZone 20 #39 January 10, 2002 IAS= Indicated Air SpeedI want to touch the sky, I want to fly so high ~ Sonique Quote Share this post Link to post Share on other sites
3fLiEr 0 #40 January 10, 2002 Skreamer - Remind me to bin myself off the lift if you ever get to jump master it!!.............why not just do the 45 angle?....... its easier!...... also you can see the ground speed as your looking at the spot..... judgement can then be made on whether a long or short delay between exits...........So when are you going to get off your arse and learn to spot......... coz I hate being jumpmaster and would love you to rather than me on lifts!!!........ bsbd"In a world where we are slaves to gravity I am pleased to be a freedom fighter" Quote Share this post Link to post Share on other sites
PhreeZone 20 #41 January 10, 2002 45 degree angle does not insure any thing. all that it does is say they have fallen the same distance down as the plane has traveled out. Unless you are giving them 7 seconds, you will end up right on top of the other group with any drift or sliding.I want to touch the sky, I want to fly so high ~ Sonique Quote Share this post Link to post Share on other sites
3fLiEr 0 #42 January 10, 2002 Surely with a strong head wind the drift on the group and the time it takes for the plane to travel enough distance to get the 45 angle your drift then will be parallel to the previous groups drift and thus you will not go over the top............ or maybe I just speak complete bollox??!?!?bsbd"In a world where we are slaves to gravity I am pleased to be a freedom fighter" Quote Share this post Link to post Share on other sites
diverdriver 6 #43 January 10, 2002 Replying to No Ones post in general......but......Ok, this thread has totally fallen into freefall drift now but I'll continue.....If the average windspeed during freefall is 60 knots then you will drift about 1 nautical mile during freefall. That "45 degree angle" will be achieved fairly quickly since the jumpers are now in drift. It DOES NOT MEAN YOU HAVE GONE ANYWHERE. You have to look at horizontal seperation and the only way to achieve that is RxT=D. Rate over the ground times Time equals Distance seperated horizontally. Now, just print out the table I posted, ask the pilot what the current (actual) groundspeed is on that load on short final for jumprun and figure it from there. It's just as hard to teach someone to truely look STRAIGHT DOWN as it is to teach them to judge a fourty five degree angle. And I believe it's harder than people make it out to be when we're flying crosswind jumpruns. People think the nose of the planes always points to where you're going and that's not the case. At least if they're counting out loud others on the load can slow them down if they are counting too fast. Or at least try to.In this whole debate we have been looking for the simplest ways which will almost always produce the widest safety margine on exits. Flat flyers before Free Flyers will always work unless you are going downwind. If you are doing downwind jumpruns the operation should be smart enough to make the change. So load the plane that way. Counting out seperation is the easiest way once the groundpseed is known to get proper seperation. No 45 degree estimation. No eyeballing the groundspeed (what if I give extra altitude? The angle change will be different and it will look like we're going slower. You can eyeball that change? You are more manly than I.)All of us here have the same goal in mind. Skydiving Safety. That is the key to this whole thread and am glad to see all the thoughtful posting.Quincy? Shit, you've got the whole county to land in and someone will give you a ride back. But here's a concept: look down during freefall and pull a little higher. Whooow! It is too bad that guy didn't go to manifest and complain. I would have liked to be on that one. Most people have no concept of real seperation. I here it all the time and just shake my head. "Well, that's the seperation we were using yesterday and it worked." That's like landing downwind saying "Well, that's the direction I landed yesterday." ;-)Chris SchindlerD-19012ATP/CFIIwww.DiverDriver.com Quote Share this post Link to post Share on other sites
skreamer 1 #44 January 10, 2002 QuoteSkreamer - Remind me to bin myself off the lift if you ever get to jump master it!!.............Thats what everybody who was on that Cessna load I JM'd last Saturday is now saying too... (but apart from my short spot, my crap canopy control and my loss of altitude awareness everything else went ok.... it was not my best skydiving day) Quote Share this post Link to post Share on other sites
3fLiEr 0 #45 January 10, 2002 "my loss of altitude awareness"& YOU DID NOT GET GROUNDED!!!..... SPAWNY BASTARD!!!!BSBD"In a world where we are slaves to gravity I am pleased to be a freedom fighter" Quote Share this post Link to post Share on other sites
billvon 3,059 #46 January 10, 2002 >Bill, what would you do if the uppers were changing constantly (direction and> speed)? At my DZ we occasionally get put on a hold at '6 000 and by the time> we are on jump run it might have been half an hour since we took off (plus we >always do two passes). Back when I was flying a lot I would get an upper-winds forecast and fly 2-3 hours later. They weren't always right, but they were never 180 degrees (or even 90 degrees) off. Unless you have some serious weather moving in, the upper winds shouldn't change much over the course of an hour.>Would you check with the pilot (if possible) to work out ground speed and time between exits? If you had time. GPS vs. airspeed is the most reliable way to tell what the uppers are. If you have GPS, though, all you really need to know is your groundspeed. If it's low, wait longer.>Also, what if the JM sucks at maths - how is he supposed to work out exit order at short order? (experience?) I hope so! As far as I can tell, no one but me does math on jump run. They just get used to high winds = 15 seconds.-bill von Quote Share this post Link to post Share on other sites
billvon 3,059 #47 January 10, 2002 >It's just as hard to teach someone to truely look STRAIGHT DOWN as it is to >teach them to judge a fourty five degree angle. I agree, especially since no one has to spot any more. It's the hardest skill to learn in spotting, partly (I think) because it sounds so easy.>No eyeballing the groundspeed (what if I give extra altitude? The angle change> will be different and it will look like we're going slower. You can eyeball that> change? You are more manly than I.)I disagree here. Even if you can't eyeball the angle, you can eyeball the ground and get a feel for distance traveled. Line anything in the plane up on a known point on the ground, and wait until that line of sight hits something 1000 feet away, and you will have travelled 1000 feet over the ground. This is the "skratch" method of ensuring exit separation, and I think it works pretty well - as long as there are landmarks you can use to judge distances fairly accurately.>Quincy? Shit, you've got the whole county to land in and someone will give you a> ride back. But here's a concept: look down during freefall and pull a little higher. Whooow!While I agree in concept, I would never tell anyone at Quincy to pull higher. There have been too many close calls from the next load opening all around someone who pulled "a little high."-bill von Quote Share this post Link to post Share on other sites
freeflir29 0 #48 January 10, 2002 "While I agree in concept, I would never tell anyone at Quincy to pull higher"Plus...I hate ruining my skydive by having to pull hi....."I got some beers....Let's Drink em!!!"Clay Quote Share this post Link to post Share on other sites
weid14 0 #49 January 10, 2002 the 45 degree angle thing doesn't always work -- what angle of attack the plane is on, and you neck calibration has much variability. Quote Share this post Link to post Share on other sites
diverdriver 6 #50 January 10, 2002 QuoteWhile I agree in concept, I would never tell anyone at Quincy to pull higher. There have been too many close calls from the next load opening all around someone who pulled "a little high."Sorry, it was a relative statement. The window is 2,000 to 3,000 for opening right? I was refering to the 3,000 side of pulling. Yep, eating somone else's canopy does suck.Chris SchindlerD-19012ATP/CFIIwww.DiverDriver.com Quote Share this post Link to post Share on other sites
