Hubsu 0 #1 January 8, 2004 I've wondered, why does the canopy plane out the dive when you yank the toggles? I tried to reason this myself, and came to something like this : "when you pull the toggles, your canopy slows down quicker than you do under the canopy. This changes the alpha of the canopy, so it tries to climb. You control the climbing by adjusting your toggles, so your altitude relative to earth is a constant. Your canopy d(alphachange)/d(t) is always positive and less at the beginning of the swoop and increasing logarithmic to the end of the swoop." Am I even close to the real thing? And if not, what makes the canopy swoop then Thanks for the answers! Quote Share this post Link to post Share on other sites
prepheckt 0 #2 January 8, 2004 There was a 4 part series in Parachutist about swooping that explained the physics of swooping, I think it was Swoop Survival or something along those lines."Dancing Argentine Tango is like doing calculus with your feet." -9 toes Quote Share this post Link to post Share on other sites
Hubsu 0 #3 January 8, 2004 Can't access Parachutist here in Finland, as it's offseason. I found the first article from that series from a French page, but it didn't answer my guestion. Quote Share this post Link to post Share on other sites
psw097 0 #4 January 8, 2004 I think it is the complex aerodynamic theory of FM. Quote Share this post Link to post Share on other sites
Spizzzarko 0 #5 January 8, 2004 All alphas and betas and phi's aside.... Lets talk about why a canoopy swoops. If you want the simplest reason here it is. A canopy will "swoop" because of the carry over of air speed after a turn. To get the longest swoop toggles or rear risers are added to change the shape or angle of the wing to create the amount of lift needed to keep the parachutist's weight still flying. Quote Share this post Link to post Share on other sites
Hubsu 0 #6 January 8, 2004 Yup Spizzzarko, that's the simple answer, I've figured that far by myself also I haven't found any websites yet to explain it more fundamental way tho. Quote Share this post Link to post Share on other sites
darkside212 0 #7 January 9, 2004 three words: speed equals lift Quote Share this post Link to post Share on other sites
psw097 0 #8 January 9, 2004 Lift = Speed² - that's even better. At least in low speed flight: Lift = + ½ pV² * Cl * Surface area Quote Share this post Link to post Share on other sites
Hubsu 0 #9 January 9, 2004 If speed equals lift, then braking the canopy should make it sink, not swoop, when you pull the toggles. Quote Share this post Link to post Share on other sites
davelepka 4 #10 January 9, 2004 "Braking" could be better stated as 're-trimming' when applied to swooping. You seem to have a good grasp of physics, and an understanding for how a canopy works. I personally don't understand what information you are looking for. While you may be able to apply it to the situation, how a canopy swoops is not rocket science. ***If speed equals lift, then braking the canopy should make it sink, not swoop, when you pull the toggles. ================================== The canopy does sink (eventually) when you pull the toggles. This is why you need to keep pulling them, and eventually put your feet down so you don't sink your ass into the dirt. Quote Share this post Link to post Share on other sites
psw097 0 #11 January 9, 2004 Well, its not that simple. Applying brakes changes the shape of the airfoil and ultimately the angle of attack. That is the next variable in the equation - Cl (coefficient of lift). This is a multiplier based a airfoil shape and AOA. That number is also were the FM (fucking magic for those that might not know) part comes into play - you won't find that number published anywhere for a skydiving wing. Quote Share this post Link to post Share on other sites
Hubsu 0 #12 January 9, 2004 Quote "Braking" could be better stated as 're-trimming' when applied to swooping. All I was after for was that line! It makes a lot more sense than my version of "braking canopies & braking human bodies". Thank you! Now I understand why the canopy planes out when I pull the toggles. I'm just too drunk to translate all the jibberish going thru my brain at the moment to english Quote Share this post Link to post Share on other sites
BrianSGermain 1 #13 January 19, 2004 there is a great deal of information in the Big Air Sportz Owner's manual, which is located on: www.bigairsportz.com It is pdf file, and completely free to download. Go for it.Instructional Videos:www.AdventureWisdom.com Keynote Speaking:www.TranscendingFEAR.com Canopies and Courses:www.BIGAIRSPORTZ.com Quote Share this post Link to post Share on other sites
BrianSGermain 1 #14 January 19, 2004 It is a matter of converting airspeed into lift, via an increase in the angle of attack. Angle of attack can be changed in one of three ways. The first is through an increase in the amount of drag produced by the canopy itself via an increase in the brakes. The greater drag of a parachute in brakes forces it to retreat behind it's neutral overhead position, which intern increases the angle of attack. The second comes as a result of rear riser application, which alters the fixed angle or trim, also known as the angle of incidence. The parachute itself achieves a higher angle of attack due to the rear riser application, and therefore increases the amount of lift it is producing. The third is through the well-timed use of the canopy's natural "recovery arc". In this method, the parachute achieves level flight due to the increased lift produced by the "A-B" section of the wing while in high speed flight. The parachute then rotates about its pitch axis all by itself, without any input by the pilot. This effect varies greatly depending on the design of the parachute, as well as the wingloading and density altitude and aggressiveness of the maneuver. I hope this answers your question completely and directly. If you want more info, try the website: www.bigairsportz.com. Brian Germain President Big Air Sportz.com.Instructional Videos:www.AdventureWisdom.com Keynote Speaking:www.TranscendingFEAR.com Canopies and Courses:www.BIGAIRSPORTZ.com Quote Share this post Link to post Share on other sites
davelepka 4 #15 January 19, 2004 Blah, blah, lift. Blah, blah, angle of this or that. What makes you such an expert? You act like you design parachutes or own a parachute company or something. Ok, just kidding, I did like the term "retreat' for describing the canopies relationship to the jumper with brake application. Quote Share this post Link to post Share on other sites
PhreeZone 15 #16 January 19, 2004 Dave.. thanks for making me actually laugh today. Those people out there that don't know who Brian is might not get it, but I did. I've actually learned a lot from Brian's manual each time I've read it. I first read it with about 100 jumps and it helped me get stand up landings. At 200 jumps I was able to understand recovery arc with it. Reading it at 350 jumps made me rethink my approaches and I stoped digging out so much. 600 jumps and midsummer came around and what do you know... I learned the difference between AOA, AOI and the rest of the factors in swooping.Yesterday is history And tomorrow is a mystery Parachutemanuals.com Quote Share this post Link to post Share on other sites
Pablito 0 #17 January 20, 2004 freaking hilarious dude "If you don't overcome your fears they will overcome you first" Shady Monkey/6Segundos Rodriguez/AKA Pablito Quote Share this post Link to post Share on other sites
murps2000 86 #18 January 20, 2004 Really nice manual! Very informative, with succinct presentation of a lot of important info and advice. Especially liked the reference to the "Tao" when describing the perfect swoop. You seem to really appreciate both the art and science of your craft. I get the impression that the manner with which a well designed airfoil so gracefully slices the air is a thing of beauty to you. Quote Share this post Link to post Share on other sites
BrianSGermain 1 #19 January 21, 2004 It makes my heart sing.Instructional Videos:www.AdventureWisdom.com Keynote Speaking:www.TranscendingFEAR.com Canopies and Courses:www.BIGAIRSPORTZ.com Quote Share this post Link to post Share on other sites
