PhreeZone 20 #26 August 19, 2002 I know most crossbraced do the same thing and its either a love/hate thing with it. It actully requires a bump of the toggles to plane the Samauri out after a dive. The flare I found was getting good surfs on the demo I was jumping was a bump at about 8 feet up then reapplying the brakes to flare about a full second after the bump.I was only doing double fronts so its hard to tell how it would react to more speed (But I'd guess only better).Yesterday is history And tomorrow is a mystery Parachutemanuals.com Quote Share this post Link to post Share on other sites
Samurai136 0 #27 August 19, 2002 The flare/ swoop is even better w/ an inch or two of rear riser. The bumping technique pulls the slack out of the brake lines and planes out the wing. ken"Buttons aren't toys." - Trillian Ken Quote Share this post Link to post Share on other sites
RichM 0 #28 August 19, 2002 Quote ... In the U.S. we use inches of mercury and a 1 inch variation equals about a 1000 foot variance -- so it's pretty easy. Since local barometric pressure only varies about 1 inch in total anyway (about 500 feet either side of normal), I think you can see it's not usually the most sigificant factor here -- temperature is. Thanks Quade, I didn't realise the relative insignificance of ground pressure to density altitude. Would it be worth adding something to that effect on your web page to cater for non fixed-wing pilots?Rich M Quote Share this post Link to post Share on other sites
quade 4 #29 August 20, 2002 Yeah, I'll have to make a couple of little revisions talking about normal local variations in pressure and I'll try to find a nice rule of thumb for the metric types. Good call.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
Staso 0 #30 August 22, 2002 Quote Additionally, as relative humidity increases molecules of air are being replaced with molecules of water. So the air becomes even less dense on a hot and humid day. Ken what do you mean that "molecules of air are being replaced with molecules of water" ? where do they go ? why are they being replaced ? if relative humidity increases there will be more water in the air and the same amount of air molecules. shouldn't air in this case get more dense ? even if they were replaced, why whould it make air less dense ? stan -- it's not about defying gravity; it's how hard you can abuse it. speed skydiving it is ... Speed Skydiving Forum Quote Share this post Link to post Share on other sites
quade 4 #31 August 22, 2002 Quoteshouldn't air in this case get more dense ? even if they were replaced, why whould it make air less dense ? Water is more dense in a liquid state than air, however, when water is a gas it is less dense than air. Why? Air is -mostly- nitrogen. Water is hydrogen and oxygen. If you have two two containers, the same size, temperature and pressure, one containing a normal mixture of dry air and the other water as a gas, then the combined molecular weight (all the protons, neutrons and electrons) of the air is more than the combined molecular weight of the water. Therefore, water as a gas is less dense.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
Staso 0 #32 August 22, 2002 Quotecombined molecular weight (all the protons, neutrons and electrons) of the air is less than the combined molecular weight of the water. Therefore, it's less dense. if water weight is more then dry air weight and thus in wet air we have more weight for the same volume, wouldn't that make wet air more dense ? more weight, the same volume = more dense, right ? stan. -- it's not about defying gravity; it's how hard you can abuse it. speed skydiving it is ... Speed Skydiving Forum Quote Share this post Link to post Share on other sites
quade 4 #33 August 22, 2002 My mistake, I said less when I should have said more. I'll correct that now.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
SkymonkeyONE 4 #34 August 22, 2002 Just to get the thread kind of back on track for the non-scientific set out there: YES, there is definitely a learning curve for every single DZ or course you are jumping. Beer line swoopers get very used to the set of visual cues they see each and every time they make their turn. People who travel and compete (not cracking on people who don't, so don't think that's my intent here) absolutely MUST show up at least one day in advance to make practice runs over the pond. Every single course is different, at least in my experience, so one must take full advantage of any practice time alloted them. Case in point: my first PPPB meet in Perris last spring. I showed up the day before the meet, late in the day due to work constraints, and only got two runs on the pond prior to competition. My sight picture was completely fucked, so the next day I was at a distinct disadvantage. I did pretty good at that meet (12th), but that was only because I got much better every round. You see, the Perris pond had absolutely no terrain to judge your turn off of. I, as a "terrain judging turner" had to modify my technique to the new sight picture I was seeing. The people that were "altimeter height turners" had a much easier time. In the end, you have two choices: start making your setup and final turn based on altitude and density (if you are jumping at a very-different altitude than normal), or show up early and ease into the new terrain. Both work equally well. Chuck Quote Share this post Link to post Share on other sites
Staso 0 #35 August 22, 2002 Quote As it gets hotter, the molecules of air are not as dense because they moving faster. Ken sorry, couldn't help it :) when it gets hotter it's less dense simply because the iar raises and the pressure drops. less molecules = less density. the fact that they move faster doesn't change density. stan. -- it's not about defying gravity; it's how hard you can abuse it. speed skydiving it is ... Speed Skydiving Forum Quote Share this post Link to post Share on other sites
Staso 0 #36 August 22, 2002 QuoteMy mistake, I said less when I should have said more. I'll correct that now. i think it's still wrong. even if water weighs less then air on molecular level, there is no "replacement". wet air = dry air + water. we have weight of dry air + weight of water, making wet air more heavy. since there is no change in volume, it makes humid air more dense. how can air + somethin be less dense then just air ? stan. -- it's not about defying gravity; it's how hard you can abuse it. speed skydiving it is ... Speed Skydiving Forum Quote Share this post Link to post Share on other sites
quade 4 #37 August 22, 2002 Quotehow can air + somethin be less dense then just air ? Because that's not actually what's happening. THIS web site has a more complete explaination than I gave. Also http://www.colby.edu/sci.tech/st215/2.2view/tsld008.htm and http://www.digest.net/bmw/archive/v9/msg00906.html and http://www.usatoday.com/weather/wdensity.htm.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
Staso 0 #38 August 23, 2002 QuoteQuotehow can air + somethin be less dense then just air ? Because that's not actually what's happening. THIS web site has a more complete explaination than I gave. Also http://www.colby.edu/sci.tech/st215/2.2view/tsld008.htm and http://www.digest.net/bmw/archive/v9/msg00906.html and http://www.usatoday.com/weather/wdensity.htm. convinced :) my mistake was that i though "no replacement happens" apperently it does: "fixed volume of gas, say one cubic meter, at the same temperature and pressure, would always have the same number of molecules no matter what gas is in the container" my assumptions will work only for closed systems. if you add water to air in closed system, it will get denser. you're right. stan. -- it's not about defying gravity; it's how hard you can abuse it. speed skydiving it is ... Speed Skydiving Forum Quote Share this post Link to post Share on other sites
skyedivr 0 #39 August 30, 2002 definately cornfused now. my power is beyond your understanding. Quote Share this post Link to post Share on other sites
Staso 0 #40 August 30, 2002 Quotedefinately cornfused now. -- it's not about defying gravity; it's how hard you can abuse it. speed skydiving it is ... Speed Skydiving Forum Quote Share this post Link to post Share on other sites
quade 4 #41 August 30, 2002 Oh, come on! Skydiving is easy! To understand it, all you need is a degree is aerodynamics, physics, chemistry, physiology, psychology . . . and everyone ology you can think of! In some special cases, animal husbandry.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
freeflir29 0 #42 August 30, 2002 QuoteIn some special cases, animal husbandry Sweet!!! 1 out of 57 ain't bad!! Quote Share this post Link to post Share on other sites
ltdiver 3 #43 August 31, 2002 QuoteIn some special cases, animal husbandry. Ok, now this is scarey. That is exactly what my first college degree was in. Really. shaking her head..., ltdiver Don't tell me the sky's the limit when there are footprints on the moon Quote Share this post Link to post Share on other sites
freeflir29 0 #44 August 31, 2002 QuoteThat is exactly what my first college degree was in. Really Wow...and you admit this in public freely? Quote Share this post Link to post Share on other sites
ltdiver 3 #45 August 31, 2002 QuoteQuoteThat is exactly what my first college degree was in. Really Wow...and you admit this in public freely? Sure. Why not? I was going into veterinary medicine at Davis University.Had to give that dream up, though, when a horse ruptured my eye back in 1988. ltdiver ps What the heck were -you- thinkin'? Don't tell me the sky's the limit when there are footprints on the moon Quote Share this post Link to post Share on other sites
freeflir29 0 #46 August 31, 2002 Quotewhen a horse ruptured my eye back in 1988 I grew up around horses...my Mom has been riding Dressage for many years. I know that horses are dangerous. That's why I took up something safe like skydiving... Quote Share this post Link to post Share on other sites
crazy 0 #47 September 2, 2002 Don't be confused. Humidity has no significant effect on air density. For canopy control, forget both the question and the answers. bb -- come-- Come Skydive Asia Quote Share this post Link to post Share on other sites
quade 4 #48 September 2, 2002 QuoteDon't be confused. Humidity has no significant effect on air density. For canopy control, forget both the question and the answers. Depends on your definition of "significant", but I will conditionally agree that for the purposes of normal canopy flight that you are, in fact, correct. I've stated as much several times in other threads. However, the reality is that humid air is less dense than dry air and in the interest of having a more complete understanding of the subject, it is a valid question.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
crazy 0 #49 September 2, 2002 QuoteDepends on your definition of "significant" to be accurate, the air density varies by ~1.5% when the relative humidity varies from 0% to 100% (standard conditions). Not objectively perceptible while flying a canopy, and far below the variations caused by other factors (mainly pressure and temperature). QuoteHowever, the reality is that humid air is less dense than dry air and in the interest of having a more complete understanding of the subject, it is a valid question. I have no doubt that the comparative density of dry and moist air is a valid question and that your answer is correct. However, this detail seems to be confusing. It is even used to support the misconception that canopies fly significantly better on dry days. -- come-- Come Skydive Asia Quote Share this post Link to post Share on other sites
