JWest 0 #401 October 24, 2015 I was taught something that is know to many to be incorrect, yes. I researched it found this thread, learned what was wrong, and haven't used it since. As for your second two "questions", not worth it, you missed what I was saying. Quote Share this post Link to post Share on other sites
ufk22 32 #402 October 24, 2015 wasatchrider am I the only one that does not know what the 45 degree rule is? It means the each successive group should open about 300' higher than the preceding one so that when you are under cnaopy you can look up or down and see other canopies at a 45 degree angleThis is the paradox of skydiving. We do something very dangerous, expose ourselves to a totally unnecesary risk, and then spend our time trying to make it safer. Quote Share this post Link to post Share on other sites
kallend 1,644 #403 October 26, 2015 yoink***At an event last week I was talking to a recently USPA certified AFF instructor (certified at well known California DZ) who said he was told by the AFF examiner to teach his students the "45 degree rule". Did he say what he did? Did he refuse and try to educate the examiner, or did he nod and smile to get the rating then ignore him? He said he was surprised and challenged the instructor but he only knew that the 45 degree myth is a bad thing and shouldn't be used. He didn't have a sufficient understanding to prove to someone that it is a bad thing. Afterwards he spoke to me at length to understand the myth so that in future he wouldn't be in that situation again.... 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
piisfish 135 #404 October 26, 2015 52 degrees is saferscissors beat paper, paper beat rock, rock beat wingsuit - KarlM Quote Share this post Link to post Share on other sites
kallend 1,644 #405 October 27, 2015 piisfish52 degrees is safer Not jumping is safer still.... 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
flyhi 24 #406 October 27, 2015 Quote"45 degree rule" is that Kelvin? degrees Fahrenheit? degrees Rankine? or degrees Celcius? Formerly jumped near a technical school where they used Pi/4 radians rule. Heard the 45 Degree Rule shouted to the newb behind us on jump run this past weekend. It was from a former TI. Yikes. Edited for operator headspacing. Thx Piisfish.Shit happens. And it usually happens because of physics. Quote Share this post Link to post Share on other sites
piisfish 135 #407 October 27, 2015 flyhi Formerly jumped near a technical school where they used Pi/4 radians rule. Heard the 45 Sec Rule shouted to the newb behind us on jump run this past weekend. It was from a former TI. Yikes. 45 seconds should be fine. Depending on the load, that could be a LOOOONG jumprun scissors beat paper, paper beat rock, rock beat wingsuit - KarlM Quote Share this post Link to post Share on other sites
377 21 #408 October 27, 2015 Exit separation is ALL ABOUT GROUND SPEED, not angles. If your ground speed is low you need a long time between potentially conflicting exits. I was on a load many years ago where we had 60+ mph winds aloft. Our ground speed on jump run was only about 10 mph. It looked like we were barely moving relative to the ground. I waited and waited and waited and REALLY pissed off the folks behind me but the wait was necessary to provide ample separation from the group that exited before me. Winds below 1000 feet were only about 18 mph but they were screaming up high. How I wish there was a reliable highly visible ground speed display that could be placed near the door. It's easy to get ground speed from GPS. GPS units are now dirt cheap. Some smart engineer ought to figure out how to do this. Internal battery powered gets it out of FAA reg territory, but replacing or recharging internal batteries is a big hassle. Maybe it could power up when a baro switch senses climbing through 10K and then shut off below that altitude. That would decrease power drain. 3772018 marks half a century as a skydiver. Trained by the late Perry Stevens D-51 in 1968. Quote Share this post Link to post Share on other sites
billvon 2,426 #409 October 27, 2015 >Exit separation is ALL ABOUT GROUND SPEED, not angles. It's about the difference in ground speed and windspeed at opening altitude. Simplifying that to ground speed works 95% of the time. Usually it gives you too much separation which is not a bad thing. Under unusual conditions (winds from a different direction at opening) it can result in too-small separations. We learned about this when we'd have a Santa Ana come through. Quite often the winds would start high then gradually lower in altitude throughout the day until they reached ground level, at which point we'd stop jumping. On those days we'd be flying jump run to the east (into the wind) but the winds at the landing area would be from the west. Under those conditions you have to add additional time, above and beyond ground speed, to ensure enough separation. The actual separation you'll get is: Separation = (groundspeed+winds at opening) * seconds between groups. Units are feet and feet per second. If the winds are going the opposite way at opening, then you have to subtract them from groundspeed. A decent rule of thumb is always leave at least seven seconds, then add two more seconds for every 10kts of uppers. (Assuming otter flying into the wind, lower winds at opening.) Quote Share this post Link to post Share on other sites
377 21 #410 October 27, 2015 I stand corrected Bill, delta ground and airspeed at opening alt. Hadn't considered that fine point. I grew up spotting for military surplus round jumps. We looked at the ground a lot. Without dropping a wind drift indicator or seeing local ground smoke you had only observed ground speed to tell you how far upwind you needed to exit. If you were covering ground slowly on an upwind jump run you took the exit point way out. This didn't account for wind gradients at different altitudes but it was usually good enough. These days I see jumpers watching those who exited before them but they don't appear to be looking at the ground to get even a rough cut at jumpship ground speed. I'd still like to see a digital ground speed display visible in back where we ride. I think it would help a lot in getting sufficient separation. 3772018 marks half a century as a skydiver. Trained by the late Perry Stevens D-51 in 1968. Quote Share this post Link to post Share on other sites
rehmwa 2 #411 November 2, 2015 kallendQuoteI was at perris a couple of weeks ago and on their waiver it said to use the 45 degree rule and give at least 10 seconds delay between groups. Counting the fleas on my cat AND leaving 10 seconds delay would work just as well. it's clear you've never had your cat near an open door of a flying airplane edit: just reviewing the old thread to find old gems. and no.....simple physics hasn't changed in the last few years - therefore, it's still a good thread ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites
diablopilot 2 #412 November 6, 2015 The ultimate problem is a bunch of fucking eggheads told everyone the 45 degree rule doesn't work, and then proceeded to write a such a complex alternative without considering if the masses could utilize it. Stress, inexperience, lack of care, or understanding, and ego, all completely negate it's usefulness. The simple fix would have been to change the name from the "45 degree rule" to the "look out the door rule".---------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites
kallend 1,644 #413 November 6, 2015 diablopilotThe ultimate problem is a bunch of fucking eggheads told everyone the 45 degree rule doesn't work, and then proceeded to write a such a complex alternative without considering if the masses could utilize it. Stress, inexperience, lack of care, or understanding, and ego, all completely negate it's usefulness. The simple fix would have been to change the name from the "45 degree rule" to the "look out the door rule". Yes counting seconds is clearly beyond the capabilities of anyone but an egghead.... 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
billvon 2,426 #414 November 6, 2015 >The ultimate problem is a bunch of fucking eggheads That's what I'm calling our eight way team next year. (Might be a better name for Prime8 come to think of it.) But if it's at Perris again, Melanie will change it to "a bunch of censored eggheads." No fun that woman. I mean, what was wrong with Snatch Force? Quote Share this post Link to post Share on other sites
chuckakers 370 #415 November 6, 2015 kallend***The ultimate problem is a bunch of fucking eggheads told everyone the 45 degree rule doesn't work, and then proceeded to write a such a complex alternative without considering if the masses could utilize it. Stress, inexperience, lack of care, or understanding, and ego, all completely negate it's usefulness. The simple fix would have been to change the name from the "45 degree rule" to the "look out the door rule". Yes counting seconds is clearly beyond the capabilities of anyone but an egghead. I don't think Diablo is giving folks enough credit. Learning how to calculate appropriate exit separation time based on wind speed and direction at various altitude intervals isn't really difficult. It's no more difficult than calculating fuel requirements for a flight by a private pilot or figuring out proper Nitrox levels for dives of various depths for a sport diver. As for the other factors cited, those don't really come into play. The calculations are done on the ground before the jump, where the jumper can take all the time needed and even get their calculations checked by a more experienced person. All that's required in the air is to be reasonably accurate at counting off seconds. That's one of the things that makes it so easy and fool proof. The complex alternative isn't complex at all for the average person with good training. In fact, if a person truly doesn't have the capacity to learn this fundamental skill I would question their capacity to skydive in the first place. I have yet to teach a jumper exit separation calculating that couldn't get it. I doubt I ever will.Chuck Akers D-10855 Houston, TX Quote Share this post Link to post Share on other sites
diablopilot 2 #416 November 19, 2015 Yet people still are not looking out the door.---------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites
chuckakers 370 #417 November 19, 2015 diablopilotYet people still are not looking out the door. True. Off topic, but true.Chuck Akers D-10855 Houston, TX Quote Share this post Link to post Share on other sites
rehmwa 2 #418 November 19, 2015 kallendYes counting seconds is clearly beyond the capabilities of anyone but an egghead. Oh - we can likely train the belly flyers. For the FF'ers I just tell them to play patty cake 1 or 2 or 3 times depending..... and for any team event (RW, VRW, freestyle), the ritual breathe and handshake usually does the trick (and then some) ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites
billvon 2,426 #419 November 19, 2015 >and for any team event (RW, VRW, freestyle), the ritual breathe and handshake >usually does the trick (and then some) Hmm. Do people in your neck of the woods do that after the previous group has exited? Around here everyone seems to do that before the door opens. But I agree that with teams there's not much of an issue. Even with a good 4-way team (Fury) climbing out as fast as they can, it typically takes 6-7 seconds from start to launch which is barely enough - but they also don't slide around in freefall. A novice team might take 10-15 seconds, which gives them more separation to deal with their sliding about. Quote Share this post Link to post Share on other sites
yuri_base 1 #420 November 24, 2015 Using a clinometer app in the mountains, I had a chance to see on many occasions how poor our (ok, at least mine) eyes are as protractors. I tend to overestimate angles by ~8 degrees on average. What seems to be 45 degrees, is actually 37. Now, tan(37) = 0.75, so for 120mph terminal it corresponds to 90mph jumprun airspeed, which is about average. So while I'm not advocating the 45 degree "rule", never used it and never heard anyone mentioning it (except, if vague memory is correct, during AFF), I can see how it came to existence - it DOES look like 45 degrees, even if the exact measurement is 37. I think using a precise instrument (camera mounted at 45 degrees) to say "look, it's not 45 degrees!" - [inline 45.jpg] - is not a valid experiment when dealing with such an imprecise instrument as human eye protractor. A more valid experiment would be to stand at the door and just ask multiple jumpers, "what do you THINK is the angle to that jumper/group?"Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio Quote Share this post Link to post Share on other sites
BrianM 1 #421 November 24, 2015 yuri_baseUsing a clinometer app in the mountains, I had a chance to see on many occasions how poor our (ok, at least mine) eyes are as protractors. I tend to overesimate angles by ~8 degrees on average. What seems to be 45 degrees, is actually 37. Now, tan(37) = 0.75, so for 120mph terminal it corresponds to 90mph jumprun airspeed, which is about average. So while I'm not advocating the 45 degree "rule", never used it and never heard anyone mentioning it (except, if vague memory is correct, during AFF), I can see how it came to existence - it DOES look like 45 degrees, even if the exact measurement is 37. I think using a precise instrument (camera mounted at 45 degrees) to say "look, it's not 45 degrees!" - - is not a valid experiment when dealing with such an unprecise instrument as human eye protractor. A more valid experiment would be to stand at the door and just ask multiple jumpers, "what do you THINK is the angle to that jumper/group?" The thing is, even if you can measure it accurately, it really doesn't matter if a jumper ever reaches 45 degrees or not, or how long it takes them to reach it (or any other angle). In fact, looking at the trajectory of the jumper relative to the aircraft is completely useless for separation, regardless of what criteria you use. Why? A jumper that has just exited is in the same air mass as the aircraft, and their trajectory will look exactly the same in 0 wind, 100 mph headwind, 100 mph tailwind (even if they *do* reach 45 degrees at some point). Using the trajectory of a just-exited jumper relative to the aircraft will result in leaving the same amount of separation regardless of winds. Debunking the 45 degree myth by explaining how jumpers never reach 45 degrees seems to be complicating the issue - NO analysis of the trajectory relative to the aircraft will work. I don't care if you look at angle, horizontal distance, or something else."It's amazing what you can learn while you're not talking." - Skydivesg Quote Share this post Link to post Share on other sites
yuri_base 1 #422 November 24, 2015 > A jumper that has just exited is in the same air mass as the aircraft, and their trajectory will look exactly the same in 0 wind, 100 mph headwind, 100 mph tailwind (even if they *do* reach 45 degrees at some point). The necessity to compensate for the wind has been discussed in so many posts and articles - "over 9000" - that I didn't mention it on purpose. I'm making a point that haven't seen mentioned before.Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio Quote Share this post Link to post Share on other sites
jumpwally 0 #423 December 29, 2015 Should make Bill Von's video a sticky !!!smile, be nice, enjoy life FB # - 1083 Quote Share this post Link to post Share on other sites
rehmwa 2 #424 December 29, 2015 billvon>and for any team event (RW, VRW, freestyle), the ritual breathe and handshake >usually does the trick (and then some) Hmm. Do people in your neck of the woods do that after the previous group has exited? Around here everyone seems to do that before the door opens. not really, the holdovers seem to be freestylists, and those small groups of freeflyers that take themselves way too seriously - but that's observed all over oh, and I have no observations of wing suiters, they could be doing the Hokey Pokey as far as I know and I try not to observe CrWDawgs either, it makes my eyes burn, so that's filed, also, under 'no data' ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites
rehmwa 2 #425 December 29, 2015 yuri_base> A jumper that has just exited is in the same air mass as the aircraft, and their trajectory will look exactly the same in 0 wind, 100 mph headwind, 100 mph tailwind (even if they *do* reach 45 degrees at some point). The necessity to compensate for the wind has been discussed in so many posts and articles - "over 9000" - that I didn't mention it on purpose. I'm making a point that haven't seen mentioned before. Brian's point is precisely correct. the point being "A jumper that has just exited is in the same air mass as the aircraft, and their trajectory will look exactly the same in 0 wind, 100 mph headwind, 100 mph tailwind" ^^^ THIS is the only thing that matters - if you are in the plane and watching the jumpers, it's a totally useless observation. Look at your finger, look at the deck of the plane, or look at the pilot is exactly equivalent the zero content info you might imagine you are getting. Look at the ground, or count your fingers is better than watching the skydivers that just left. At least you get some useable information Your ability to understand why others came up with a false notion is commendable though - maybe that empathy is a good thing and will help efforts in convincing them why they are wrong. Good luck ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites
