DrewEckhardt 0 #26 January 28, 2009 QuoteQuoteCan any "modern" (post ZP and semi elliptical) wing be safely landed from half brakes? I know it works for lighter WL (I've landed mine) but how does this scale with higher WL? Sure. The slower you start the harder you land. Why do you want to do that? Ultimately because you screwed up at higher altitudes, had some head wind, and used brakes to get a steeper glide path and had insufficient room to return to full flight before landing. Before then you do it so you're comfortable and aren't trying it for the first time when lots has gone wrong. Quote Share this post Link to post Share on other sites
phoenixlpr 0 #27 January 28, 2009 Quote A fresh fat airfoil seven cell canopy is NOT the same thing as a ragged out student canopy approximating what a recreational skydiver would jump just bigger. I have jumped accuracy canopies before I got my license. Does it count as a first hand experience? Quote Share this post Link to post Share on other sites
phoenixlpr 0 #28 January 28, 2009 QuoteBefore then you do it so you're comfortable and aren't trying it for the first time when lots has gone wrong. Like what? Landing is landing. Keep wing in level Keep it flying - do not stall It would be better to know the minimum altitude required for full recovery.... Quote Share this post Link to post Share on other sites
gravitysurfer 0 #29 January 28, 2009 QuoteQuoteIt is the square footage (and the accordingly slow stall speed) that makes it possible to 'sink in' an accuracy canopy. Come in high over the bullseye, once you are centered up, apply brakes until the wind speed matches your air speed. I guess we'll agree to disagree. Sure, with enough wind, a velocity will sink straight down. But aerodynamically, it's completely different from what an accuracy canopy is doing. An accuracy canopy can sink in zero wind. Even downwind. A Velocity 238 wouldn't be able to sink like a Classic 238. An Icarus 330 will not sink like a Parafoil. It's not about size, it's about canopy design. davelepka- pilotdave has described the reasoning for my response to your original statement that acc. canopies are designed to fly like every other canopy and the only difference is they are huge. While I have not flown an accuracy canopy, I have observed many fly and land. I've also guided and landed thousands of students under FC Manta 288s as a radio operator. My personal observations indicate to me significant flight characteristic differences between the two. Regardless of size similarity. Viewing the attached picture of an accuracy canopy, I see pretty apparent design differences from a Manta as well. Just my .02 cheers aloha. Quote Share this post Link to post Share on other sites
davelepka 4 #30 January 28, 2009 QuoteSure, with enough wind, a velocity will sink straight down. But aerodynamically, it's completely different from what an accuracy canopy is doing. Pilotdave- No it's not different at all. You equal your airspeed with the wind speed, and your net result is zero ground speed, the canopy sinks straight. Aerodynamically different would be if you pulled a string that cloed off the nose, and turned into a round. That would be different. QuoteMy personal observations indicate to me significant flight characteristic differences between the two. Regardless of size similarity. Gravitysurfer - I agree that there are differences in many factors between accuracy canopies, and others, but none of these differences are exclusive to accuracy canopies, which is what makes them the same as every other ram-air canopy. Here's an example - take a Velo, and a ParaFoil. -different number of cells - different line type -different aspect ratio -different line trim -different thinkness of the wing See, all of these things are different, however if were to look at the same facotrs in comparing a Velo to a Katana, you find that all or most of those differences still appear, even though the Katana is very close to the Velo in both design and intended use. Accuracy canopies don't poses any 'magic' that make them any different in their operation than any other canopy. They have design features that lend them toward better performance in one area or another, but they remain ram-air canopies, and operate on the same principals as every other ram-air canopy. Quote Share this post Link to post Share on other sites
gravitysurfer 0 #31 January 28, 2009 The only other difference I would add is the 'overhang' of the top skin along the leading edge. Giving an accuracy canopy the ability to sink "straight down" in zero ground wind condition or even down wind while still maintaining it's full inflation. Not unlike a ROUND aloha. Quote Share this post Link to post Share on other sites
d123 1 #32 January 28, 2009 Don't they have vents to keep the inflation while flying backwards or in a stall? OMG I can't believe that I my attention got stuck in a drift of my post and I'm flowing with it Lock, Dock and Two Smoking Barrelrolls! Quote Share this post Link to post Share on other sites
gravitysurfer 0 #33 January 28, 2009 Sorry d123. Although debate is healthy, I guess we have diverted from your OP. aloha. Quote Share this post Link to post Share on other sites
d123 1 #34 January 28, 2009 I've got my answer so drift away! Lock, Dock and Two Smoking Barrelrolls! Quote Share this post Link to post Share on other sites
pilotdave 0 #35 January 28, 2009 QuotePilotdave- No it's not different at all. You equal your airspeed with the wind speed, and your net result is zero ground speed, the canopy sinks straight. You can't see the difference in aerodynamics between doing that at 20 mph of airspeed vs 0 airspeed? Think of the airflow around the canopy. Think of the difference in angle of attack. Coming straight down on a windy day on my sabre2 is a completely different sensation than sinking an accuracy canopy. The accuracy canopy has an entire mode of flight not available on a regular canopy... at least not available in any useful way. Toggles above your shoulder area is flare, below shoulders is sink. Regardless of wind. It's what happens with a sport canopy right before it stalls. But much more stable of course. I'm not saying accuracy canopies have some magical ability to sink that other canopies don't have. I'm saying they are designed with features and flight characteristics that let them sink... something other canopies can't do. It's not magic, it's design. And it's not size. Dave Quote Share this post Link to post Share on other sites
loumeinhart 0 #36 June 2, 2009 Quotebelow shoulders is sink I have a question. If you come straight down in zero wind.. is that a sink or stall? I'm thinking in terms of the wing/airfoil, I know you can't do that with a glider right? Quote Share this post Link to post Share on other sites
DrewEckhardt 0 #37 June 2, 2009 QuoteQuotebelow shoulders is sink I have a question. If you come straight down in zero wind.. is that a sink or stall? I'm thinking in terms of the wing/airfoil, I know you can't do that with a glider right? Aerodynamically it's probably a stall. In accuracy / BASE jumper lingo it's a sink, the difference being that if you were stalled the canopy would be going backwards some and down at a higher rate of speed. And it takes a _lot_ more than shoulder height to get there. A normal accuracy approach starts at about 2/3 brakes. Quote Share this post Link to post Share on other sites
