kelpdiver 2 #26 September 20, 2005 Quote For any given path to the ground can your peak horizontal speed exceed your peak vertical speed? Instinctively I would say no but the correct answer is yes. The speed of a truly horizonal swoop cannot exceed the peak vertical speed because the only way a parachute gains speed is by descending. It would violate conservation of energy. The key flaw is this simple physics approach is wind. But as a rule, flying craft can fall straight down much faster than they can go flat. Your slide example would only hold up for those that don't do aggressive turns. Quote Share this post Link to post Share on other sites
diablopilot 2 #27 September 21, 2005 QuoteI jump without an AAD - not too many of us left... More than you might think, but usually only those of us that DO think.---------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites
riddler 0 #28 September 21, 2005 QuoteThe speed of a truly horizonal swoop cannot exceed the peak vertical speed because the only way a parachute gains speed is by descending. It would violate conservation of energy. Now we're getting to parts that I don't understand, since I don't swoop. What do you mean by "true swoop"? From a pure physics standpoint, it should be possible for forward speed to exceed any previous horizontal speed; with enough time you can build up the energy, then plane it out for some immediate horizontal speed. But that wouldn't exactly be a hookturn. By true swoop, do you mean a hookturn?Trapped on the surface of a sphere. XKCD Quote Share this post Link to post Share on other sites
kelpdiver 2 #29 September 21, 2005 by truly horizonal swoop I meant that the canopy was not losing any altitude. At that point you can't gain speed. But in going to physics, I focused on the speed rather than velocity, which was the entire point of raymod's posting. So I'm no longer sure about anything in the math. A carving dive can continue to accelerate nearly all the way to horizonal, without the vertical speed being that high. But somewhere drag becomes important since they do start with a big dive to build speed. Quote Share this post Link to post Share on other sites
RMURRAY 1 #30 September 22, 2005 don't mean to take this off topic but for all you physics professors if travelling 91mph horizontal how low could you cut away and deploy a reserve - lets say with a skyhook? rm Quote Share this post Link to post Share on other sites
HydroGuy 0 #31 September 23, 2005 Seems to me that it would be awfully simple to design an AAD for swoopers or with a swoop mode that would turn off after a given period of time under canopy...it would be there solely to protect them from a door/tail strike. If they can make an AAD, they can make one turn off. How many people would actually buy a swoop-only AAD though?Get in - Get off - Get away....repeat as neccessary Quote Share this post Link to post Share on other sites
UDSkyJunkie 0 #32 September 23, 2005 QuoteNow we're getting to parts that I don't understand, since I don't swoop. What do you mean by "true swoop"? From a pure physics standpoint, it should be possible for forward speed to exceed any previous horizontal speed; with enough time you can build up the energy, then plane it out for some immediate horizontal speed. But that wouldn't exactly be a hookturn. By true swoop, do you mean a hookturn? Conservation of energy, as Kelpdiver said, is the answer to this. A canopy has only "potential energy," read: energy due to elevation above the ground. As you decend, you can convert the potential to kinetic... speed. Once you have run out of altitude, you have used up all your potential energy... meaning you no longer can gain any more speed. SO.. IF (and of course this isn't real) you were to go instantaneously from vertical from horizontal, and in the abscence of loss of energy to to air resistance, your horizontal speed would be equal to your vertical. In real life, you still lose some altitude in transition to the horizontal, so you gain a little... you also lose a little to air resistance... so the answer is you MIGHT be able to go faster horizontally that veritcally, but not much. I can't imagine it being the difference between less than 78 mph and 90+. On a side note, I love being an engineer, and knowing the answers to some of this stuff"Some people follow their dreams, others hunt them down and beat them mercilessly into submission." Quote Share this post Link to post Share on other sites
riddler 0 #33 September 23, 2005 Sure, if you're talking about going from pure verticle to pure horizontal. The original question that started this topic was this: Quotehow do you end up going 91mph horizontally? Does this not involve going 91mph vertically then pulling out of the dive? Answer (I believe) is that you can get to 91 horizontal without ever getting near 91 vertical. Long, steep dive, to build up a lot of KE over time, then plane it out at the end. But that's not exactly a hookturn.Trapped on the surface of a sphere. XKCD Quote Share this post Link to post Share on other sites
kelpdiver 2 #34 September 23, 2005 Quote Answer (I believe) is that you can get to 91 horizontal without ever getting near 91 vertical. Long, steep dive, to build up a lot of KE over time, then plane it out at the end. But that's not exactly a hookturn. so how steep? 60 degrees? Just going by the sound the canopy makes, it seems to me that they're hitting peak very shortly before the planeout. Not idea how much less speed they had in the steepest part of the dive. Are there any instruments to measure, perhaps some sort of drag meter? Quote Share this post Link to post Share on other sites
riddler 0 #35 September 24, 2005 Sure, I've had friends that have taken wind speed indicators with them under canopy. ryoder has taken a small portable hand-held. I think the brand was Kestrel, or something like that. But I doubt a swooper would want to hold a wind-speed indicator in one hand while trying to negotiate a canopy at that speed. Might be better to stick with ground radar.Trapped on the surface of a sphere. XKCD Quote Share this post Link to post Share on other sites
riddler 0 #36 October 24, 2005 Quote the new Argus does have a swoop mode. not sure if it is for sale quite yet. Not for sale yet, AFAIK. I talked to a guy that is supposed to demo a prototype sometime in the next few months.Trapped on the surface of a sphere. XKCD Quote Share this post Link to post Share on other sites
rhys 0 #37 October 26, 2005 when freestyle/freefly came in the container manufacturers had to evolve to accomodate for the new found dangers. how hard could it be for the aad manufacturers to devlop an aad the accomodates swoopers.(obviously not that hard, it is being done already) swoopers are only gong to get faster, longer and more neumerous."When the power of love overcomes the love of power, then the world will see peace." - 'Jimi' Hendrix Quote Share this post Link to post Share on other sites
