spootch 0 #1 January 30, 2011 Anyone got any tips/tricks on getting a canopy to fly straight? I had a person come to me about a sabre2 with a nasty right turn in it. At first I thought it could be asymetrical harness (be it hips or actual rig) so I hooked it up to my rig and jumped it. Sure as shit, it buggered off to the right. The lines checked out fine, however before I could get into the material and have a look see, he pitched it and relaced it with another (which flew fine). Fast forward, I now have a vision (05) that has a slight turn to the right that requires a bit of toggle to keep straight. The lines are ok, brake lines have lots of slack and the material (ribs n skins) don't seem to to have an obvious flaw ie: a wrong rib size in one cell. It was suggested that sewing from one side to another can cause a slight turn if the manufacturers arent carefull ? Thoughts? And no I'm not sewing a pair of underwear to one side for drag, even if it works! Quote Share this post Link to post Share on other sites
theonlyski 8 #2 January 30, 2011 Check the lines, above the cascades on the breaks. I had somehow managed to get a small 'ring' of some sort of fibers rolled up, that went up the lines to the cascades and kept them from fully opening up, putting a right turn in the canopy that took a little toggle to keep it straight. A 1 second job with a pair of scissors, and it flew like a champ. Just wish I would have snapped a picture first. The trick is, check the WHOLE LINE, as it may just roll down the lines if you were to just pull the lines above the cascade apart to spot it."I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly DPH -7, TDS 578, Muff 5153, SCR 14890 I'm an asshole, and I approve this message Quote Share this post Link to post Share on other sites
dragon2 2 #3 January 30, 2011 That's a known problem with (earlier) sabre2's. I'd ship it back to PD. ciel bleu, Saskia Quote Share this post Link to post Share on other sites
Ronaldo 0 #4 January 30, 2011 It is usually in the fabric. Making a symmetrical lineset is really easy when comparing to the parachute itself. Checking the lineset for correct construction and symmetry is also much easier. Canopy construction has 2 main issues: - Zp fabric distorts in the bias when tension is applied (it holds well when tension is applied aligned with the ripstop fibers). This requires that all panels are aligned perfectly during construction. If one panel is sewn slightly out of alignment it will inflate distorted in relation to its mirror on the other side thus inducing a turn. Try this with your PC, pull the fabric in the direction of the ripstop fibers then in the bias. - Sewing involves applying tension in thread, fabric and reinforcement tape. If the tension varies too much you may create cells that inflate asymmetrically thus inducing the turn. The far from the center a cell is the bigger will be the effect of any asymmetry. The usual fix for built in turns is to create asymmetry in the lines for compensation (cutting them on the opposite side) This is an engineer analysis, riggers can certainly add more infoEngineering Law #5: The most vital dimension on any plan drawing stands the most chance of being omitted Quote Share this post Link to post Share on other sites
chuckakers 426 #5 January 30, 2011 Send it back to the manufacturer. I don't know about other brands, but as a former dealer I can say for sure that PD WANTS customers to send back problem canopies so they can examine it to determine what's wrong. Just one more reason I have nothing but PD's in my rig.Chuck Akers D-10855 Houston, TX Quote Share this post Link to post Share on other sites
stayhigh 2 #6 January 30, 2011 is there any reason why it happens mostly on 190-210 ish canopy, with jumper having less than 200 jumps???Bernie Sanders for President 2016 Quote Share this post Link to post Share on other sites
Skydivesg 7 #7 January 30, 2011 What do you mean by "pitched it"?Be the canopy pilot you want that other guy to be. Quote Share this post Link to post Share on other sites
Beatnik 2 #8 January 30, 2011 QuoteSend it back to the manufacturer. I don't know about other brands, but as a former dealer I can say for sure that PD WANTS customers to send back problem canopies so they can examine it to determine what's wrong. Just one more reason I have nothing but PD's in my rig. I like PD's support but sometimes I found it to be less useful and a waste of energy. A friend of mine bought a brand new Stiletto 150 and it didn't fly straight. We found that some of the line attachment points were sewn asymmetrically from side to side on the canopy and there was something else that escapes me at the moment. After sending it to them, they said it was all within tolerance and didn't do anything about it. Overall their support is pretty good but this case it wasn't and the canopy doesn't fly straight. Quote Share this post Link to post Share on other sites
spootch 0 #9 January 30, 2011 Quoteis there any reason why it happens mostly on 190-210 ish canopy, with jumper having less than 200 jumps??? lol. both the canopies are 150s. it has been my experience the more the wingload the more the "accent" of the canopy shows through Quote Share this post Link to post Share on other sites
spootch 0 #10 January 30, 2011 QuoteWhat do you mean by "pitched it"? Sold it, and yes the buyer was well aware of the turn in the canopy. I suspect a rigger? Quote Share this post Link to post Share on other sites
