Date: Fri, 16 Sep 1994 11:06:47 -1000 From: cbush@orion.it.luc.edu (Cady) Message-Id: <35d1d7$2tj@apollo.it.luc.edu> Organization: Loyola University of Chicago Subject: Re-bridling a parafoil Help! My big parafoil continues to list. No matter what I do I can't get it bridled correctly. Is there a simple method for knowing how long the lines must be. The one time I had them leveled I snagged it and all my slip knots came out. Until I get this right my kite won't get above 15'. It just spirals back down to the ground. I appreciate any suggestions. -Cady = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Sat, 17 Sep 1994 16:38:10 -1000 From: foiler21@aol.com (Foiler21) Message-Id: <35g96i$prf@newsbf01.news.aol.com> Organization: America Online, Inc. (1-800-827-6364) Subject: Re: Re-bridling a parafoil In article <35d1d7$2tj@apollo.it.luc.edu>, cbush@orion.it.luc.edu (Cady) writes: Help, my big parafoil continues to list......... To start with how wide is the 'foil?? A good all-round ballpark length for bridle lines is twice the width of the kite. i.e. if the foil is 7 feet wide, try making ythe bridle 14 feet long, etc., etc. If you gang tie all the bridles for one row ( across the kite ) together and hook that knot over a suitable point, now tie all the individual bridles on to each individual keel/ventral/flare so that they are all the same length. this will give a slight crown across the kite. Repeat process for second row, third row, etc,.etc. Now just come up with a system for adjusting the angle of flight of the kite with short adjustment lines between each gang/bulk knot and a tow ring. Usually leaving the front row fixed and adjusting the second, third rows works. Remember to keep the bottom of the foil flat from front to rear. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Sun, 18 Sep 1994 06:51:02 -1000 From: ahclem0013@aol.com (AhClem0013) Message-Id: <35hr5m$6u9@newsbf01.news.aol.com> Organization: America Online, Inc. (1-800-827-6364) Subject: Re: Re-bridling a parafoil In article <35g96i$prf@newsbf01.news.aol.com>, foiler21@aol.com (Foiler21) writes: Some stuff about bridling, what else; Thought we might welcome Stretch Tucker to the net via aol. Stretch brings his on brand of humor and insight to our group.He's learning his way around his new keyboard, having recently returned from Europe and hopefully we will be seeing more stuff from him in the future. Welcome Stretch. aoxomoxoa = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Sun, 18 Sep 1994 17:04:02 -1000 From: alfa@werple.apana.org.au (Glenn Durden) Message-Id: <35iv32$he2@werple.apana.org.au> Organization: werple public-access unix, Melbourne Subject: Re: Re-bridling a parafoil cbush@orion.it.luc.edu (Cady) writes: >Help! My big parafoil continues to list. No matter what I do I can't get >it bridled correctly. Is there a simple method for knowing how long the >lines must be. The one time I had them leveled I snagged it and all my >slip knots came out. >Until I get this right my kite won't get above 15'. It just spirals back >down to the ground. >I appreciate any suggestions. Actually I'd like to know, myself. I still havnt quite stabilised my home-brew parafoil. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Sun, 18 Sep 1994 19:25:50 -1000 From: spsl@warthog.ru.ac.za (MR SC LAWRIE) Message-Id: Organization: Rhodes University Subject: Re: Re-bridling a parafoil >In article <35d1d7$2tj@apollo.it.luc.edu>, cbush@orion.it.luc.edu (Cady) >writes: >Help, my big parafoil continues to list......... I have successfully rigged several 14ft foils...heres my method...it may work for you. Lay the foil flat on the ground with the left-most rib & flares/fins laid out so they're visible. Find a point halfway between the front & middle fins, about 1.5 times the length of the rib away from the kite. All the bridling lines should meet at this point - the front & centre will be about equal, the rear ones will be a bit longer. Now you need 9 strong rings....tie all the front-fin lines on the left of the kite to one, all the front-fin ones on the right to the next, all the middle-fin left to the next etc etc (call 'em sub-bridles). Now tie each of the left subbridless to another (stronger) ring (call it a main-ring), and all the right-side ones to another, using lengths of about 20cm. These make it easy to do macro adjustments to the rigging. You can then either tie a single towing line to both main rings if you wish to fly single line, or fly dual line attached to each main rings (gives some maneuverability, but not like a stunt kite!). You will probably have to spend some time fiddling with the lengths of the 6 bits of line from the main rings to the sub-bridles. The easiest way is to tie a line about 2 - 3 m long between the two main rings, and loop it behind your back so you can manually pull in the subbridles while the kite is inflated to get the best settings...this is when the kite is damn nearly over your head without actually collapsing. The left-right list problem is easiest sorted out by adjusting the lengths of the substring between the main rings and the back subbridles. If the worst comes to the worst you *can* still play with the lengths of the lines >From the subbridles to to back left and back right fins on the kite, but I've never had to do this yet. I must confess that this method does leave a pile of rings hanging round under the kite, but it works and is easy to adjust. I frequently adjust my foils to the windspeed of the day when I go fly/get dragged around/whatever. good luck, Steve sub-bridling points to a > To start with how wide is the 'foil?? A good all-round ballpark length >for bridle lines is twice the width of the kite. i.e. if the foil is 7 >feet wide, try making ythe bridle 14 feet long, etc., etc. >If you gang tie all the bridles for one row ( across the kite ) together >and hook that knot over a suitable point, now tie all the individual >bridles on to each individual keel/ventral/flare so that they are all the >same length. this will give a slight crown across the kite. >Repeat process for second row, third row, etc,.etc. >Now just come up with a system for adjusting the angle of flight of the >kite with short adjustment lines between each gang/bulk knot and a tow >ring. Usually leaving the front row fixed and adjusting the second, third >rows works. Remember to keep the bottom of the foil flat from front to >rear. +-----------------------------------------------------------------------------+ | Steve Lawrie P.O.Box 360 Grahamstown 6140 South Africa Tel +27 461 25631 | +-----------------------------------------------------------------------------+ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 19 Sep 1994 03:08:08 -1000 From: pat@cs.strath.ac.uk (Patrick Prosser) Message-Id: <35k2fo$6i0@todd-06.cs.strath.ac.uk> Organization: Comp. Sci. Dept., Strathclyde Univ., Glasgow, Scotland. Subject: Re: Re-bridling a parafoil In article <35d1d7$2tj@apollo.it.luc.edu> cbush@orion.it.luc.edu (Cady) writes: #Help! My big parafoil continues to list. No matter what I do I can't get #it bridled correctly. Is there a simple method for knowing how long the #lines must be. The one time I had them leveled I snagged it and all my #slip knots came out. # #Until I get this right my kite won't get above 15'. It just spirals back #down to the ground. # #I appreciate any suggestions. # First, I would strongly recommend bridling the parafoil such that it is FLAT. In my experience crown rigging is not as good, resulting in loss of stability. (1) Deal with this on a ROW basis, ie going across the foil on the first set of keels. Measure the altitude of the keel (Ka), and the distance between keels left to right (Kd) (2) As a general rule the longer the bridle lines the better. Assume the width of the foil is W and that we would like bridles to be roughly 3 times width (3W). (3) Further let us assume (for simplicity) that we have 5 keels on each row (so its 4 units wide and W=4, Kd = 1), numbered 1 to 5 (4) Shroud line SL1 = SL5 = sqrt(2*Kd*2*Kd + 3W*3W) - Ka Shroud line SL2 = Sl4 = sqrt(1*Kd*1*Kd + 3W*3W) - Ka Shroud line SL3 = sqrt(0*Kd*0*Kd + 3W*3W) - Ka (ie 3W - Ka) This is just computing the hypotenuse of a right angle triangle. Note that you should also include in your calculations a constant for knots at either end of the shroud lines!! The above give "roll" adjustment. You now gather together the shroud lines on common rows. Note that we make all effective lengths the same (ie go for a right angled triangle with altitude 3W regardless of row on the foil). There are a number of ways to get pitch adjustment. Lets assume you have 2 rows of keels. Then connect a line from collection of lines on row 1 to collection of lines on row 2, and put a ring on this line. You can now slide back and forards for pitch. If you have 3 lines ... connect the last and middle collections together (!!) passing the connecting line throug a ring of some kind. Now conect a line to the collection of the front shroud lines to that ring, and place a ring on the line that goes from the 1st collection. This front ring now gives pitch adjustment, and rear ring automatically tensiones the mid and rear keels (neat ?). You can now do 4 with same technique. You will find that if front lines are too long kite does NOT climb, and rolls. If front lines are too short kite yaws (wags its tail) and over-flies. My preference is to get foil to the point where it is about to over fly, and reduce yaw with a VERY long fuzzy tail (not a drouge). Typically tail is about 10 times length of foil. I adjust bridle AND tail length according to wind conditions. In storm conditions (more than 40 mph) I fly a very small 21 keeled foil (about 1m square) As wind speed drops I increase size of foil. All my foils now have cross flow venting (not crucial, but good practice) and bleed holes at the rear (reduces drag at front of foil). All are now flat bridled, with ability to adjust pitch on site in seconds (no knot tying/untying) Patrick = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 19 Sep 1994 15:10:47 -1000 From: dickbell@netcom.com (Dick Bell) Message-Id: Organization: NETCOM On-line Communication Services (408 261-4700 guest) Subject: Re: Re-bridling a parafoil Foiler21 (foiler21@aol.com) wrote: : To start with how wide is the 'foil?? A good all-round ballpark length : for bridle lines is twice the width of the kite. i.e. if the foil is 7 : feet wide, try making ythe bridle 14 feet long, etc., etc. : If you gang tie all the bridles for one row ( across the kite ) together : and hook that knot over a suitable point, now tie all the individual : bridles on to each individual keel/ventral/flare so that they are all the : same length. this will give a slight crown across the kite. : Repeat process for second row, third row, etc,.etc. : Now just come up with a system for adjusting the angle of flight of the : kite with short adjustment lines between each gang/bulk knot and a tow : ring. Usually leaving the front row fixed and adjusting the second, third : rows works. Remember to keep the bottom of the foil flat from front to : rear. Hi Stretch, Good to see you on the net. George did get your genki at Junction. I knew he would. It looks great in the Texas sky. Talk to ya later. P.S. Tell Carrol that Gail and I say HI. :-) To stay on subject.... it doesn't take much change on the bridle lines to make a big change. One way to help with the length is to mark each line and then tie at the mark. Ensuring equal lengths. -- -------------------------------------------------------------------------------- Dick Bell dickbell@netcom.com Dallas, Texas = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =