AggieDave 6 #1 November 14, 2003 This has come up in the "carving" thread, about old canopy myths that are being debunked, etc. This got me thinking, wondering what sort of information that I know and hold to be true, that may infact be incorrect. My first thought is about recovery arcs in wind, my thought is that when there is wind, a canopy with a short recovery arc will have a shorter recovery arc, due to the airspeed coming out of the "corner" of a dive. Those with more experience/knowledge (Hooknswoop, etc), please debunk that if it needs to be debunked. I'm sure there are many more that may or may not be true, so please post some if you have them.--"When I die, may I be surrounded by scattered chrome and burning gasoline." Quote Share this post Link to post Share on other sites
Jimbo 0 #2 November 14, 2003 QuoteMy first thought is about recovery arcs in wind, my thought is that when there is wind, a canopy with a short recovery arc will have a shorter recovery arc, due to the airspeed coming out of the "corner" of a dive. We've already determined though that airspeed is constant though, regardless of wind, didn't we? Why would any canopy recover more quickly on a high wind day? - Jim"Like" - The modern day comma Good bye, my friends. You are missed. Quote Share this post Link to post Share on other sites
diablopilot 2 #3 November 15, 2003 QuoteMy first thought is about recovery arcs in wind, my thought is that when there is wind, a canopy with a short recovery arc will have a shorter recovery arc, due to the airspeed coming out of the "corner" of a dive. Yup. Not true. How about: "Go to 1/2 to 3/4 in turbulance" Yeah right. Lets just go and REDUCE the internal pressure of that canopy in turbulance shall we?!---------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites
billdo 0 #4 November 15, 2003 QuoteQuote How about: "Go to 1/2 to 3/4 in turbulance" Yeah right. Lets just go and REDUCE the internal pressure of that canopy in turbulance shall we?! I've wondered about that because my thinking was to "let it fly" or even go to double fronts to increase the pressure, but when I asked a well-known xaos team pilot at Eloy he said to go to halfs if cought in a dust devil. ?? Quote Share this post Link to post Share on other sites Jimbo 0 #5 November 15, 2003 I don't think that going to double fronts would increase the internal pressure. Would it? Anyone? - Jim"Like" - The modern day comma Good bye, my friends. You are missed. Quote Share this post Link to post Share on other sites parachutist 1 #6 November 15, 2003 Quote I don't think that going to double fronts would increase the internal pressure. Would it? Anyone? - Jim Basically anything that increases your air speed will, in turn, increase the pressure inside your ram-air canopy. It's just like a wind sock: the higher the wind speed, then the more air is getting shoved inside. The resulting higher pressure inside the wind sock will make the wind sock stand out more. Another analogy: close your mouth and blow a little, inflating your cheeks. Blow a little bit harder and you will feel the additional pressure. Quote Share this post Link to post Share on other sites ianmdrennan 2 #7 November 15, 2003 QuoteI asked a well-known xaos team pilot at Eloy he said to go to halfs if cought in a dust devil. I don't know a thing about dust devils but they happen low to the ground right? If so I'd assume the pilot would be trying to soften the impact in this scenario by going to half brakes. Dunno - anyone with dust devil experience know any other reason why the XAOS pilot would say this? Blue skies IanPerformance Designs Factory Team Quote Share this post Link to post Share on other sites skycat 0 #8 November 15, 2003 QuoteDunno - anyone with dust devil experience know any other reason why the XAOS pilot would say this? The odds of your canopy collapsing is greater in a dust devil than in any normal turbulance. By going into half brakes you are basically putting your canopy in the same configuration as when it opens with toggles stowed. This in turn allows your canopy to re-inflate faster than if you had the toggles all the way up. When it comes to dust devils though all bets are off and your best bet is to avoid it.Fly it like you stole it! Quote Share this post Link to post Share on other sites johnny1488 1 #9 November 15, 2003 I've thought about the extra air speed thing. I've heard 2 schools of thought. One is yours, the other is that double fronts deform the airfoil, thus making the canopy more succeptable to turbulence. Scott Miller said its a give and take situation. More airpressure is good, but now your probably heading for the ground a lot faster and if you have a collapse... Johnny --"This ain't no book club, we're all gonna die!" Mike Rome Quote Share this post Link to post Share on other sites parachutist 1 #10 November 15, 2003 QuoteI've thought about the extra air speed thing. I've heard 2 schools of thought. One is yours, the other is that double fronts deform the airfoil, thus making the canopy more succeptable to turbulence. Scott Miller said its a give and take situation. More airpressure is good, but now your probably heading for the ground a lot faster and if you have a collapse... Oops, I didn't realize that turbulence was part of this equation. I thought it was a straightforward question about whether not pressure would increase Right, I don't think that double fronts through turbulent conditions near the ground would be such a great idea. Letting the canopy go to full flight is the advice I've always gotten & it seems like the best idea in turbulent conditions. Chris Quote Share this post Link to post Share on other sites grega 0 #11 November 15, 2003 Hmm actually the pressure inside the canopy is never higher than the pressure of the air at that altitude temperature and humidity. The air pressurises at speeds waaay higher than you could fly with any canopy (more than 300mph) What changes is the pressure that is around the canopy, which get's even less, so the canopy is even more "tight" (streched apart). it's the same think why the canopy is pressurised. because the pressure outside is less than the pressure inside the canopy. and inside the canopy pressure is always same as the pressure that is at the stagnation point (few inches infront of the canopy) But nevertheless, the faster you go, the bigger the difference in pressures, more rigid the wing is."George just lucky i guess!" Quote Share this post Link to post Share on other sites Hooknswoop 19 #12 November 15, 2003 QuoteHmm actually the pressure inside the canopy is never higher than the pressure of the air at that altitude temperature and humidity. The air pressurises at speeds waaay higher than you could fly with any canopy (more than 300mph) Then explain how an airspeed indicator works at less than 40 mph.......... The air pressure inside a canopy is higher than the static air pressure near the canopy. Derek Quote Share this post Link to post Share on other sites grega 0 #13 November 16, 2003 Quote Then explain how an airspeed indicator works at less than 40 mph.......... I don't know, but i'd like to find out."George just lucky i guess!" Quote Share this post Link to post Share on other sites AndyMan 7 #14 November 16, 2003 I understand that the preasure inside the canopy is pretty much normal, but its a low preasure area above the canopy which keeps it inflated...? _Am__ You put the fun in "funnel" - craichead. Quote Share this post Link to post Share on other sites Hooknswoop 19 #15 November 16, 2003 An airspeed indicator works with a pitot tube and a static port. It compares the ram-air pressure coming into the pitot tube with ambient pressure from the static port to give airspeed. The ram-air pressure into the pitot tube begins immediately and increases with airspeed. The same thing with a canopy. It flys through the air and rams air into it, creating a higher pressure inside the canopy than outside the canopy. The low pressure (lifting force) is only above the canopy from the shape of the upper surface. One atmosphere is only 14.7 PSI. A few PSI is enough to make the canopy quite rigid, like a mylar helium balloon. Derek Quote Share this post Link to post Share on other sites grega 0 #16 November 16, 2003 I looked closely into it and you're totaly right. i can't even remember where i read what i was claiming before. But obviously i misunderstood something when i read that... Anyway hooknswoop is right. The internal pressure is higher."George just lucky i guess!" Quote Share this post Link to post Share on other sites kallend 1,623 #17 November 16, 2003 QuoteQuote I don't think that going to double fronts would increase the internal pressure. Would it? Anyone? - Jim Basically anything that increases your air speed will, in turn, increase the pressure inside your ram-air canopy. It's just like a wind sock: the higher the wind speed, then the more air is getting shoved inside. The resulting higher pressure inside the wind sock will make the wind sock stand out more. Another analogy: close your mouth and blow a little, inflating your cheeks. Blow a little bit harder and you will feel the additional pressure. But the opening on a wind sock is at the front. The openings on a high performance canopy are usually under the nose. If you move the stagnation point away from the openings by lowering the AOA too much you will initiate a top skin collapse starting at the LE. Going to 1/4 brakes will keep the stagnation point down under the nose where the openings are.... 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 apoil 0 #18 November 17, 2003 Quote The odds of your canopy collapsing is greater in a dust devil than in any normal turbulance. By going into half brakes you are basically putting your canopy in the same configuration as when it opens with toggles stowed. This in turn allows your canopy to re-inflate faster than if you had the toggles all the way up. Maybe I'm misreading this. You don't stow your toggles to make your canopy inflate faster. you stow your toggles so that you don't open in full flight - which is dangerous if there's any kind of problem like a malfunction or an imminent collision. It also HURTS because it's a faster opening. I see no reason half brakes would allow for faster reinflation. Quote Share this post Link to post Share on other sites breadhead 0 #19 November 17, 2003 Straight from the PD website: http://www.performancedesigns.com/faq.htm Quote If you find yourself in turbulent conditions, we recommend flying at full glide. At full glide, the canopy will penetrate through turbulence better, and be less affected by it. Contrary to what some people have been told, flying in brakes does not necessarily help keep the canopy pressurized. Aerodynamically, the canopy is actually more susceptible to turbulence in brakes. Years ago, flying in half brakes seemed to make some older ram-air canopy designs more stable in turbulence, though they were obviously very different from modern canopies. Flying in brakes is definitely not the best technique to use with the canopies we're flying today, although a lot of skydivers are still told to use this technique. Quote Share this post Link to post Share on other sites sammer 0 #20 November 17, 2003 I would have to agree with that. In my short (75 jumps) skydiving carreer I have been caught in turbulence quite a few times and I have tried all three approaches: Brakes, full glide and double fronts. The double fronts seem to make the turbulence more violent but the 1/4 brake approach caused my canopy to collapse and reinflate violently pointing the wrong way every time. I was taught that 1/4 brakes are best for turbulence, but I am thoroughly convinced that is bullshit. My canopy is big and lightly loaded, so this might not apply to everyone, but I know full glide works best for me. Quote Share this post Link to post Share on other sites diablopilot 2 #21 November 17, 2003 QuoteYou don't stow your toggles to make your canopy inflate faster. you stow your toggles so that you don't open in full flight - which is dangerous if there's any kind of problem like a malfunction or an imminent collision. It also HURTS because it's a faster opening. I see no reason half brakes would allow for faster reinflation. Actually you stow them for both reasons. If you have closed end cells on your main, what do you do to get them inflated? Pump the brakes. Flying in turbulance should be in full flight. That gives you the best internal pressure, and platform stability to get through the turbulance. If you suffer a collapse of any sort, pumping the brakes while keeping the wing level till you establish reinflation, or you are forced to flare for landing is the best course of action. Remember when low to the ground the key point is keeping the wing level, no matter what you have over your head. A partial canopy landed straight in is preferable to a partial canopy landed in a spiraling turn. As for the inlets being located lower on the nose of a high performance design, think about the angle of attack of the canopy. They are right in line with it. Stay full flight, especially on an elliptical. They have peculiar inflation characteristics sometimes.---------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites rigging65 0 #22 November 17, 2003 QuoteYou don't stow your toggles to make your canopy inflate faster. Ummmm....actually...you do. Try jumping without your breaks stowed. The openings are much longer. It takes more time to pressurize the canopy, since there is more volume to fill...among other things. As for using breaks in turbulence, the most important thing is to keep the wing level. Some say 1/2 breaks, others (PD) say it doesn't really matter. BUT, keeping the wing level and flying the canopy all the time is the most important thing you can do under canopy...regardless of the adverse conditions you're in. "...and once you had tasted flight, you will walk the earth with your eyes turned skyward. For there you have been, and there you long to return..." Quote Share this post Link to post Share on other sites AndyMan 7 #23 November 17, 2003 Quote Ummmm....actually...you do. Try jumping without your breaks stowed. The openings are much longer. It takes more time to pressurize the canopy, since there is more volume to fill...among other things. That's odd. I've jumped a few times without brakes stowed, and each opening has been a slammer... _Am__ You put the fun in "funnel" - craichead. Quote Share this post Link to post Share on other sites Hooknswoop 19 #24 November 17, 2003 QuoteThat's odd. I've jumped a few times without brakes stowed, and each opening has been a slammer... I think it depends on the canopy. I jumped an FX w/o the brakes set and it snivelled for 1000+ feet. The faster the canopy flys, the more internal pressure it has, which helps it resist collapsing, and the more lift it produces, which helps it resist collapsing. The flip side is if it does collapse, you are going faster near the ground and have less time to fix it and you may hit harder if you can’t get it re-inflated prior to impact. More speed may make turbulence feel more intense, but that is only because you are flying through the updrafts and downdrafts (or rotors) faster. Kinda like hitting a speed bump slow or fast. Hitting it fast makes it feel harder, but the speed bump is the same size weather you hit it slow or fast. So the best method to keep the canopy from collapsing is the worst thing to do if those efforts fail and it does collapse. The worst thing to do in turbulence is go to deep brakes. This lowers the internal pressure of the canopy and you are more susceptible to the canopy collapsing. You are flying slower, which is good if the canopy does collapse, but it may not have collapsed in the first place if you have been at full flight. My plan for handling turbulence is full flight until it actually begins to fold up. Then what ever is necessary to get it to re-inflate, keep it flying straight, and keep it over my head. Of course the best plan is too learn where turbulence can most likely be found and avoid those areas or don’t jump in turbulent, gusty conditions. Derek Quote Share this post Link to post Share on other sites freakydiver 0 #25 November 17, 2003 I've found with my Sabre I flying full is the best remedy to turb. Quarter and half brakes only seem to make things worse. My two cents of course. -- (N.DG) "If all else fails – at least try and look under control." -- Quote Share this post Link to post Share on other sites Prev 1 2 Next Page 1 of 2 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 Go To Topic Listing
Jimbo 0 #5 November 15, 2003 I don't think that going to double fronts would increase the internal pressure. Would it? Anyone? - Jim"Like" - The modern day comma Good bye, my friends. You are missed. Quote Share this post Link to post Share on other sites
parachutist 1 #6 November 15, 2003 Quote I don't think that going to double fronts would increase the internal pressure. Would it? Anyone? - Jim Basically anything that increases your air speed will, in turn, increase the pressure inside your ram-air canopy. It's just like a wind sock: the higher the wind speed, then the more air is getting shoved inside. The resulting higher pressure inside the wind sock will make the wind sock stand out more. Another analogy: close your mouth and blow a little, inflating your cheeks. Blow a little bit harder and you will feel the additional pressure. Quote Share this post Link to post Share on other sites ianmdrennan 2 #7 November 15, 2003 QuoteI asked a well-known xaos team pilot at Eloy he said to go to halfs if cought in a dust devil. I don't know a thing about dust devils but they happen low to the ground right? If so I'd assume the pilot would be trying to soften the impact in this scenario by going to half brakes. Dunno - anyone with dust devil experience know any other reason why the XAOS pilot would say this? Blue skies IanPerformance Designs Factory Team Quote Share this post Link to post Share on other sites skycat 0 #8 November 15, 2003 QuoteDunno - anyone with dust devil experience know any other reason why the XAOS pilot would say this? The odds of your canopy collapsing is greater in a dust devil than in any normal turbulance. By going into half brakes you are basically putting your canopy in the same configuration as when it opens with toggles stowed. This in turn allows your canopy to re-inflate faster than if you had the toggles all the way up. When it comes to dust devils though all bets are off and your best bet is to avoid it.Fly it like you stole it! Quote Share this post Link to post Share on other sites johnny1488 1 #9 November 15, 2003 I've thought about the extra air speed thing. I've heard 2 schools of thought. One is yours, the other is that double fronts deform the airfoil, thus making the canopy more succeptable to turbulence. Scott Miller said its a give and take situation. More airpressure is good, but now your probably heading for the ground a lot faster and if you have a collapse... Johnny --"This ain't no book club, we're all gonna die!" Mike Rome Quote Share this post Link to post Share on other sites parachutist 1 #10 November 15, 2003 QuoteI've thought about the extra air speed thing. I've heard 2 schools of thought. One is yours, the other is that double fronts deform the airfoil, thus making the canopy more succeptable to turbulence. Scott Miller said its a give and take situation. More airpressure is good, but now your probably heading for the ground a lot faster and if you have a collapse... Oops, I didn't realize that turbulence was part of this equation. I thought it was a straightforward question about whether not pressure would increase Right, I don't think that double fronts through turbulent conditions near the ground would be such a great idea. Letting the canopy go to full flight is the advice I've always gotten & it seems like the best idea in turbulent conditions. Chris Quote Share this post Link to post Share on other sites grega 0 #11 November 15, 2003 Hmm actually the pressure inside the canopy is never higher than the pressure of the air at that altitude temperature and humidity. The air pressurises at speeds waaay higher than you could fly with any canopy (more than 300mph) What changes is the pressure that is around the canopy, which get's even less, so the canopy is even more "tight" (streched apart). it's the same think why the canopy is pressurised. because the pressure outside is less than the pressure inside the canopy. and inside the canopy pressure is always same as the pressure that is at the stagnation point (few inches infront of the canopy) But nevertheless, the faster you go, the bigger the difference in pressures, more rigid the wing is."George just lucky i guess!" Quote Share this post Link to post Share on other sites Hooknswoop 19 #12 November 15, 2003 QuoteHmm actually the pressure inside the canopy is never higher than the pressure of the air at that altitude temperature and humidity. The air pressurises at speeds waaay higher than you could fly with any canopy (more than 300mph) Then explain how an airspeed indicator works at less than 40 mph.......... The air pressure inside a canopy is higher than the static air pressure near the canopy. Derek Quote Share this post Link to post Share on other sites grega 0 #13 November 16, 2003 Quote Then explain how an airspeed indicator works at less than 40 mph.......... I don't know, but i'd like to find out."George just lucky i guess!" Quote Share this post Link to post Share on other sites AndyMan 7 #14 November 16, 2003 I understand that the preasure inside the canopy is pretty much normal, but its a low preasure area above the canopy which keeps it inflated...? _Am__ You put the fun in "funnel" - craichead. Quote Share this post Link to post Share on other sites Hooknswoop 19 #15 November 16, 2003 An airspeed indicator works with a pitot tube and a static port. It compares the ram-air pressure coming into the pitot tube with ambient pressure from the static port to give airspeed. The ram-air pressure into the pitot tube begins immediately and increases with airspeed. The same thing with a canopy. It flys through the air and rams air into it, creating a higher pressure inside the canopy than outside the canopy. The low pressure (lifting force) is only above the canopy from the shape of the upper surface. One atmosphere is only 14.7 PSI. A few PSI is enough to make the canopy quite rigid, like a mylar helium balloon. Derek Quote Share this post Link to post Share on other sites grega 0 #16 November 16, 2003 I looked closely into it and you're totaly right. i can't even remember where i read what i was claiming before. But obviously i misunderstood something when i read that... Anyway hooknswoop is right. The internal pressure is higher."George just lucky i guess!" Quote Share this post Link to post Share on other sites kallend 1,623 #17 November 16, 2003 QuoteQuote I don't think that going to double fronts would increase the internal pressure. Would it? Anyone? - Jim Basically anything that increases your air speed will, in turn, increase the pressure inside your ram-air canopy. It's just like a wind sock: the higher the wind speed, then the more air is getting shoved inside. The resulting higher pressure inside the wind sock will make the wind sock stand out more. Another analogy: close your mouth and blow a little, inflating your cheeks. Blow a little bit harder and you will feel the additional pressure. But the opening on a wind sock is at the front. The openings on a high performance canopy are usually under the nose. If you move the stagnation point away from the openings by lowering the AOA too much you will initiate a top skin collapse starting at the LE. Going to 1/4 brakes will keep the stagnation point down under the nose where the openings are.... 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 apoil 0 #18 November 17, 2003 Quote The odds of your canopy collapsing is greater in a dust devil than in any normal turbulance. By going into half brakes you are basically putting your canopy in the same configuration as when it opens with toggles stowed. This in turn allows your canopy to re-inflate faster than if you had the toggles all the way up. Maybe I'm misreading this. You don't stow your toggles to make your canopy inflate faster. you stow your toggles so that you don't open in full flight - which is dangerous if there's any kind of problem like a malfunction or an imminent collision. It also HURTS because it's a faster opening. I see no reason half brakes would allow for faster reinflation. Quote Share this post Link to post Share on other sites breadhead 0 #19 November 17, 2003 Straight from the PD website: http://www.performancedesigns.com/faq.htm Quote If you find yourself in turbulent conditions, we recommend flying at full glide. At full glide, the canopy will penetrate through turbulence better, and be less affected by it. Contrary to what some people have been told, flying in brakes does not necessarily help keep the canopy pressurized. Aerodynamically, the canopy is actually more susceptible to turbulence in brakes. Years ago, flying in half brakes seemed to make some older ram-air canopy designs more stable in turbulence, though they were obviously very different from modern canopies. Flying in brakes is definitely not the best technique to use with the canopies we're flying today, although a lot of skydivers are still told to use this technique. Quote Share this post Link to post Share on other sites sammer 0 #20 November 17, 2003 I would have to agree with that. In my short (75 jumps) skydiving carreer I have been caught in turbulence quite a few times and I have tried all three approaches: Brakes, full glide and double fronts. The double fronts seem to make the turbulence more violent but the 1/4 brake approach caused my canopy to collapse and reinflate violently pointing the wrong way every time. I was taught that 1/4 brakes are best for turbulence, but I am thoroughly convinced that is bullshit. My canopy is big and lightly loaded, so this might not apply to everyone, but I know full glide works best for me. Quote Share this post Link to post Share on other sites diablopilot 2 #21 November 17, 2003 QuoteYou don't stow your toggles to make your canopy inflate faster. you stow your toggles so that you don't open in full flight - which is dangerous if there's any kind of problem like a malfunction or an imminent collision. It also HURTS because it's a faster opening. I see no reason half brakes would allow for faster reinflation. Actually you stow them for both reasons. If you have closed end cells on your main, what do you do to get them inflated? Pump the brakes. Flying in turbulance should be in full flight. That gives you the best internal pressure, and platform stability to get through the turbulance. If you suffer a collapse of any sort, pumping the brakes while keeping the wing level till you establish reinflation, or you are forced to flare for landing is the best course of action. Remember when low to the ground the key point is keeping the wing level, no matter what you have over your head. A partial canopy landed straight in is preferable to a partial canopy landed in a spiraling turn. As for the inlets being located lower on the nose of a high performance design, think about the angle of attack of the canopy. They are right in line with it. Stay full flight, especially on an elliptical. They have peculiar inflation characteristics sometimes.---------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites rigging65 0 #22 November 17, 2003 QuoteYou don't stow your toggles to make your canopy inflate faster. Ummmm....actually...you do. Try jumping without your breaks stowed. The openings are much longer. It takes more time to pressurize the canopy, since there is more volume to fill...among other things. As for using breaks in turbulence, the most important thing is to keep the wing level. Some say 1/2 breaks, others (PD) say it doesn't really matter. BUT, keeping the wing level and flying the canopy all the time is the most important thing you can do under canopy...regardless of the adverse conditions you're in. "...and once you had tasted flight, you will walk the earth with your eyes turned skyward. For there you have been, and there you long to return..." Quote Share this post Link to post Share on other sites AndyMan 7 #23 November 17, 2003 Quote Ummmm....actually...you do. Try jumping without your breaks stowed. The openings are much longer. It takes more time to pressurize the canopy, since there is more volume to fill...among other things. That's odd. I've jumped a few times without brakes stowed, and each opening has been a slammer... _Am__ You put the fun in "funnel" - craichead. Quote Share this post Link to post Share on other sites Hooknswoop 19 #24 November 17, 2003 QuoteThat's odd. I've jumped a few times without brakes stowed, and each opening has been a slammer... I think it depends on the canopy. I jumped an FX w/o the brakes set and it snivelled for 1000+ feet. The faster the canopy flys, the more internal pressure it has, which helps it resist collapsing, and the more lift it produces, which helps it resist collapsing. The flip side is if it does collapse, you are going faster near the ground and have less time to fix it and you may hit harder if you can’t get it re-inflated prior to impact. More speed may make turbulence feel more intense, but that is only because you are flying through the updrafts and downdrafts (or rotors) faster. Kinda like hitting a speed bump slow or fast. Hitting it fast makes it feel harder, but the speed bump is the same size weather you hit it slow or fast. So the best method to keep the canopy from collapsing is the worst thing to do if those efforts fail and it does collapse. The worst thing to do in turbulence is go to deep brakes. This lowers the internal pressure of the canopy and you are more susceptible to the canopy collapsing. You are flying slower, which is good if the canopy does collapse, but it may not have collapsed in the first place if you have been at full flight. My plan for handling turbulence is full flight until it actually begins to fold up. Then what ever is necessary to get it to re-inflate, keep it flying straight, and keep it over my head. Of course the best plan is too learn where turbulence can most likely be found and avoid those areas or don’t jump in turbulent, gusty conditions. Derek Quote Share this post Link to post Share on other sites freakydiver 0 #25 November 17, 2003 I've found with my Sabre I flying full is the best remedy to turb. Quarter and half brakes only seem to make things worse. My two cents of course. -- (N.DG) "If all else fails – at least try and look under control." -- Quote Share this post Link to post Share on other sites Prev 1 2 Next Page 1 of 2 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
ianmdrennan 2 #7 November 15, 2003 QuoteI asked a well-known xaos team pilot at Eloy he said to go to halfs if cought in a dust devil. I don't know a thing about dust devils but they happen low to the ground right? If so I'd assume the pilot would be trying to soften the impact in this scenario by going to half brakes. Dunno - anyone with dust devil experience know any other reason why the XAOS pilot would say this? Blue skies IanPerformance Designs Factory Team Quote Share this post Link to post Share on other sites
skycat 0 #8 November 15, 2003 QuoteDunno - anyone with dust devil experience know any other reason why the XAOS pilot would say this? The odds of your canopy collapsing is greater in a dust devil than in any normal turbulance. By going into half brakes you are basically putting your canopy in the same configuration as when it opens with toggles stowed. This in turn allows your canopy to re-inflate faster than if you had the toggles all the way up. When it comes to dust devils though all bets are off and your best bet is to avoid it.Fly it like you stole it! Quote Share this post Link to post Share on other sites
johnny1488 1 #9 November 15, 2003 I've thought about the extra air speed thing. I've heard 2 schools of thought. One is yours, the other is that double fronts deform the airfoil, thus making the canopy more succeptable to turbulence. Scott Miller said its a give and take situation. More airpressure is good, but now your probably heading for the ground a lot faster and if you have a collapse... Johnny --"This ain't no book club, we're all gonna die!" Mike Rome Quote Share this post Link to post Share on other sites
parachutist 1 #10 November 15, 2003 QuoteI've thought about the extra air speed thing. I've heard 2 schools of thought. One is yours, the other is that double fronts deform the airfoil, thus making the canopy more succeptable to turbulence. Scott Miller said its a give and take situation. More airpressure is good, but now your probably heading for the ground a lot faster and if you have a collapse... Oops, I didn't realize that turbulence was part of this equation. I thought it was a straightforward question about whether not pressure would increase Right, I don't think that double fronts through turbulent conditions near the ground would be such a great idea. Letting the canopy go to full flight is the advice I've always gotten & it seems like the best idea in turbulent conditions. Chris Quote Share this post Link to post Share on other sites
grega 0 #11 November 15, 2003 Hmm actually the pressure inside the canopy is never higher than the pressure of the air at that altitude temperature and humidity. The air pressurises at speeds waaay higher than you could fly with any canopy (more than 300mph) What changes is the pressure that is around the canopy, which get's even less, so the canopy is even more "tight" (streched apart). it's the same think why the canopy is pressurised. because the pressure outside is less than the pressure inside the canopy. and inside the canopy pressure is always same as the pressure that is at the stagnation point (few inches infront of the canopy) But nevertheless, the faster you go, the bigger the difference in pressures, more rigid the wing is."George just lucky i guess!" Quote Share this post Link to post Share on other sites
Hooknswoop 19 #12 November 15, 2003 QuoteHmm actually the pressure inside the canopy is never higher than the pressure of the air at that altitude temperature and humidity. The air pressurises at speeds waaay higher than you could fly with any canopy (more than 300mph) Then explain how an airspeed indicator works at less than 40 mph.......... The air pressure inside a canopy is higher than the static air pressure near the canopy. Derek Quote Share this post Link to post Share on other sites
grega 0 #13 November 16, 2003 Quote Then explain how an airspeed indicator works at less than 40 mph.......... I don't know, but i'd like to find out."George just lucky i guess!" Quote Share this post Link to post Share on other sites
AndyMan 7 #14 November 16, 2003 I understand that the preasure inside the canopy is pretty much normal, but its a low preasure area above the canopy which keeps it inflated...? _Am__ You put the fun in "funnel" - craichead. Quote Share this post Link to post Share on other sites
Hooknswoop 19 #15 November 16, 2003 An airspeed indicator works with a pitot tube and a static port. It compares the ram-air pressure coming into the pitot tube with ambient pressure from the static port to give airspeed. The ram-air pressure into the pitot tube begins immediately and increases with airspeed. The same thing with a canopy. It flys through the air and rams air into it, creating a higher pressure inside the canopy than outside the canopy. The low pressure (lifting force) is only above the canopy from the shape of the upper surface. One atmosphere is only 14.7 PSI. A few PSI is enough to make the canopy quite rigid, like a mylar helium balloon. Derek Quote Share this post Link to post Share on other sites
grega 0 #16 November 16, 2003 I looked closely into it and you're totaly right. i can't even remember where i read what i was claiming before. But obviously i misunderstood something when i read that... Anyway hooknswoop is right. The internal pressure is higher."George just lucky i guess!" Quote Share this post Link to post Share on other sites
kallend 1,623 #17 November 16, 2003 QuoteQuote I don't think that going to double fronts would increase the internal pressure. Would it? Anyone? - Jim Basically anything that increases your air speed will, in turn, increase the pressure inside your ram-air canopy. It's just like a wind sock: the higher the wind speed, then the more air is getting shoved inside. The resulting higher pressure inside the wind sock will make the wind sock stand out more. Another analogy: close your mouth and blow a little, inflating your cheeks. Blow a little bit harder and you will feel the additional pressure. But the opening on a wind sock is at the front. The openings on a high performance canopy are usually under the nose. If you move the stagnation point away from the openings by lowering the AOA too much you will initiate a top skin collapse starting at the LE. Going to 1/4 brakes will keep the stagnation point down under the nose where the openings are.... 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
apoil 0 #18 November 17, 2003 Quote The odds of your canopy collapsing is greater in a dust devil than in any normal turbulance. By going into half brakes you are basically putting your canopy in the same configuration as when it opens with toggles stowed. This in turn allows your canopy to re-inflate faster than if you had the toggles all the way up. Maybe I'm misreading this. You don't stow your toggles to make your canopy inflate faster. you stow your toggles so that you don't open in full flight - which is dangerous if there's any kind of problem like a malfunction or an imminent collision. It also HURTS because it's a faster opening. I see no reason half brakes would allow for faster reinflation. Quote Share this post Link to post Share on other sites
breadhead 0 #19 November 17, 2003 Straight from the PD website: http://www.performancedesigns.com/faq.htm Quote If you find yourself in turbulent conditions, we recommend flying at full glide. At full glide, the canopy will penetrate through turbulence better, and be less affected by it. Contrary to what some people have been told, flying in brakes does not necessarily help keep the canopy pressurized. Aerodynamically, the canopy is actually more susceptible to turbulence in brakes. Years ago, flying in half brakes seemed to make some older ram-air canopy designs more stable in turbulence, though they were obviously very different from modern canopies. Flying in brakes is definitely not the best technique to use with the canopies we're flying today, although a lot of skydivers are still told to use this technique. Quote Share this post Link to post Share on other sites
sammer 0 #20 November 17, 2003 I would have to agree with that. In my short (75 jumps) skydiving carreer I have been caught in turbulence quite a few times and I have tried all three approaches: Brakes, full glide and double fronts. The double fronts seem to make the turbulence more violent but the 1/4 brake approach caused my canopy to collapse and reinflate violently pointing the wrong way every time. I was taught that 1/4 brakes are best for turbulence, but I am thoroughly convinced that is bullshit. My canopy is big and lightly loaded, so this might not apply to everyone, but I know full glide works best for me. Quote Share this post Link to post Share on other sites
diablopilot 2 #21 November 17, 2003 QuoteYou don't stow your toggles to make your canopy inflate faster. you stow your toggles so that you don't open in full flight - which is dangerous if there's any kind of problem like a malfunction or an imminent collision. It also HURTS because it's a faster opening. I see no reason half brakes would allow for faster reinflation. Actually you stow them for both reasons. If you have closed end cells on your main, what do you do to get them inflated? Pump the brakes. Flying in turbulance should be in full flight. That gives you the best internal pressure, and platform stability to get through the turbulance. If you suffer a collapse of any sort, pumping the brakes while keeping the wing level till you establish reinflation, or you are forced to flare for landing is the best course of action. Remember when low to the ground the key point is keeping the wing level, no matter what you have over your head. A partial canopy landed straight in is preferable to a partial canopy landed in a spiraling turn. As for the inlets being located lower on the nose of a high performance design, think about the angle of attack of the canopy. They are right in line with it. Stay full flight, especially on an elliptical. They have peculiar inflation characteristics sometimes.---------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites
rigging65 0 #22 November 17, 2003 QuoteYou don't stow your toggles to make your canopy inflate faster. Ummmm....actually...you do. Try jumping without your breaks stowed. The openings are much longer. It takes more time to pressurize the canopy, since there is more volume to fill...among other things. As for using breaks in turbulence, the most important thing is to keep the wing level. Some say 1/2 breaks, others (PD) say it doesn't really matter. BUT, keeping the wing level and flying the canopy all the time is the most important thing you can do under canopy...regardless of the adverse conditions you're in. "...and once you had tasted flight, you will walk the earth with your eyes turned skyward. For there you have been, and there you long to return..." Quote Share this post Link to post Share on other sites
AndyMan 7 #23 November 17, 2003 Quote Ummmm....actually...you do. Try jumping without your breaks stowed. The openings are much longer. It takes more time to pressurize the canopy, since there is more volume to fill...among other things. That's odd. I've jumped a few times without brakes stowed, and each opening has been a slammer... _Am__ You put the fun in "funnel" - craichead. Quote Share this post Link to post Share on other sites
Hooknswoop 19 #24 November 17, 2003 QuoteThat's odd. I've jumped a few times without brakes stowed, and each opening has been a slammer... I think it depends on the canopy. I jumped an FX w/o the brakes set and it snivelled for 1000+ feet. The faster the canopy flys, the more internal pressure it has, which helps it resist collapsing, and the more lift it produces, which helps it resist collapsing. The flip side is if it does collapse, you are going faster near the ground and have less time to fix it and you may hit harder if you can’t get it re-inflated prior to impact. More speed may make turbulence feel more intense, but that is only because you are flying through the updrafts and downdrafts (or rotors) faster. Kinda like hitting a speed bump slow or fast. Hitting it fast makes it feel harder, but the speed bump is the same size weather you hit it slow or fast. So the best method to keep the canopy from collapsing is the worst thing to do if those efforts fail and it does collapse. The worst thing to do in turbulence is go to deep brakes. This lowers the internal pressure of the canopy and you are more susceptible to the canopy collapsing. You are flying slower, which is good if the canopy does collapse, but it may not have collapsed in the first place if you have been at full flight. My plan for handling turbulence is full flight until it actually begins to fold up. Then what ever is necessary to get it to re-inflate, keep it flying straight, and keep it over my head. Of course the best plan is too learn where turbulence can most likely be found and avoid those areas or don’t jump in turbulent, gusty conditions. Derek Quote Share this post Link to post Share on other sites
freakydiver 0 #25 November 17, 2003 I've found with my Sabre I flying full is the best remedy to turb. Quarter and half brakes only seem to make things worse. My two cents of course. -- (N.DG) "If all else fails – at least try and look under control." -- Quote Share this post Link to post Share on other sites
