Date: Sun, 17 Jul 1994 21:00:16 -1000 From: malle@dbag.ulm.daimlerbenz.com (Bernhard Malle) Message-Id: <9407180700.AA18430@dagobert> Organization: Division of Applied Sciences, Harvard University Subject: profile for parafoil Hello to all parafoil-experts, (and to all others) I have built a soft-centipede a la Peter Lynn, and now I am looking for a lifting device. I own already a flowform (from the rowland book) but Peter, Simo, Esben and me have all made the experience, that it is not very reliable (Hi Jeff). Now I am looking for a good parafoil. I have got the book of Schimmelpfennig and the parafoil in the book seems to be ok, but perhaps there is someone on the net that knows about a still better parafoil? Thanks for any help Bernhard +-------------------------------------------+ | Bernhard Malle | | Bernhard.Malle@dbag.ulm.daimlerbenz.com | | Ulm, Germany | +-------------------------------------------+ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 18 Jul 1994 05:47:07 -1000 From: crowell@teleport.com (Carl Crowell) Message-Id: <30e85s$kh9@elaine.teleport.com> Organization: Teleport - Portland's Public Access (503) 220-1016 Subject: Re: profile for parafoil : Hello to all parafoil-experts, (and to all others) : Now I am looking for a good parafoil. I have got the book of : Schimmelpfennig and the parafoil in the book seems to be ok, but : perhaps there is someone on the net that knows about a still : better parafoil? I have been building parafoils 1-10 m. sq. for a few years now. Look for a patern to show up in Hawaii soon. I have a 65sq. ft. (bout 8'x8') that works well in winds 3.5mph to 40+. I have the full plans on my mac, I am just redoing them on a P.C. Question: How about a full size Giff or other format file to print out in tiles so that you have an instant patern. carl -- crowell@teleport.COM Public Access User --- Not affiliated with TECHbooks Public Access UNIX and Internet at (503) 220-1016 (2400-14400, N81) = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 18 Jul 1994 22:32:46 -1000 From: salanne@convex.csc.FI (Simo Salanne) Message-Id: <30g33e$4i9@pobox.csc.fi> Organization: Centre for Scintific Computing Subject: Re: profile for parafoil In <9407180700.AA18430@dagobert> malle@dbag.ulm.daimlerbenz.com (Bernhard Malle) writes: >Hello to all parafoil-experts, (and to all others) >I have built a soft-centipede a la Peter Lynn, and now I am looking >for a lifting device. I own already a flowform (from the rowland book) ... >Now I am looking for a good parafoil. I have got the book of Bernhard, you don't let your sewing machine get rusted:-) Simo -- Simo.Salanne@csc.fi STACK Finland = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Tue, 19 Jul 1994 04:46:08 -1000 From: sasaki@das.harvard.edu (Marty Sasaki) Message-Id: Organization: Harvard University OIT/NSD Subject: Re: profile for parafoil This is from memory, but I believe Irving Reid (do you still read this Irving?) mentioned that both Doug Hagaman and George Ham both use slightly thinner airfoil sections on their foils than are usually cited in books on parafoil construction... -- Marty Sasaki Harvard University Sasaki Kite Fabrications sasaki@noc.harvard.edu Network Services Division 26 Green Street 617-496-4320 10 Ware Street Jamaica Plain, MA 02130 Cambridge, MA 02138-4002 phone/fax: 617-522-8546 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Tue, 19 Jul 1994 16:36:01 -1000 From: sasaki@das.harvard.edu (Marty Sasaki) Message-Id: Organization: Harvard OIT Network Services Subject: Re: profile for parafoil In article <30h9kl$13o@elaine.teleport.com> crowell@teleport.com (Carl Crowell) writes: >An airfoil primer: by carl... no, I don't really KNOW anything..but my >guess is: These are really small nits, but I think it is a good idea to try to use the existing terminology correctly. >Cord Length: The distance from the front bottom to the back. Actually, the cord is the distance from the front of the airfoil to the back, not necessarily from the bottom, but the most forward point. >Angle of Attack: (I don't know why its called this) The angle between >the bottome cord length and the mouth. The angle of attack is the angle between the camber line and the airflow. The angle of attack changes as the kite rises, being very high near the ground and less and less as it nears the top of it's flight. >Crown Point: The is the point of maximum seperation between the bottom >and the crown of the rib. Or simply put, the widest point on the rib. Of course this assumes that the bottom of the airfoil is a straight line. For parafoils this is reasonable, but for many airfoils this is not true. This value is the the high point of the airfoil. It is usually specified as a percentage of the cord. ------------------------------------------ This brings up something that I've been thinking of doing. I've been thinking of presenting an introduction to aerodynamics. There are lots of misconceptions out there about aerodynamics. There are lots of misconceptions about things like aspect ratio, "induced camber", bernoulli lift vs. other types of lift, etc. If such a session were given, would you attend? I guess I'm trying to get a feeling for how useful this kind of presentation would be. Please send me email on this... -- Marty Sasaki Harvard University Sasaki Kite Fabrications sasaki@noc.harvard.edu Network Services Division 26 Green Street 617-496-4320 10 Ware Street Jamaica Plain, MA 02130 Cambridge, MA 02138-4002 phone/fax: 617-522-8546 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Tue, 19 Jul 1994 09:30:29 -1000 From: crowell@teleport.com (Carl Crowell) Message-Id: <30h9kl$13o@elaine.teleport.com> Organization: Teleport - Portland's Public Access (503) 220-1016 Subject: Re: profile for parafoil Marty Sasaki (sasaki@netop3.harvard.edu) wrote: : This is from memory, but I believe Irving Reid (do you still read this : Irving?) mentioned that both Doug Hagaman and George Ham both use : slightly thinner airfoil sections on their foils than are usually : cited in books on parafoil construction... An airfoil primer: by carl... no, I don't really KNOW anything..but my guess is: Lets divide up the RIB of the parafoil, this is the cross sectional support that divides up each cell. On profile, this will aproximate the airfoil of your kite. Cord Length: The distance from the front bottom to the back. Crown Length: The distance (along the arc of the crown) from the front top to the back. Mouth: The open at the front of the kite. This is the space between the bottom cord lenght and the crown length. Angle of Attack: (I don't know why its called this) The angle between the bottome cord length and the mouth. Crown Point: The is the point of maximum seperation between the bottom and the crown of the rib. Or simply put, the widest point on the rib. Set value: Cord Lenght equals 1.0 Crown length: >1.0 (but close, often 'bout 1.1) Mouth: 0.07 - 0.16 Angle of attack: 112 deg. - 122 deg. Crown Point: 0.1x0.1 to 0.2-0.2 (*.*x*.* means that it is *.* back from the leading edge of the crown length and *.* high. - If the kite falls in these ranges it will more likely than not fly. I think.. oh well... the exact plans that I use will bere here in a few days. I am still having trouble working on large size drawing on my machine. Corel 3.0 won't allow an item over 30"x30", and I will probibly make a scalled drawing that need to be printed at 500 0.000000or a 65 sq. ft kite, and at 700 0.000000or a 100 sq. ft. Two Two Two great paterns for the disk space of one. carl -- crowell@teleport.COM Public Access User --- Not affiliated with TECHbooks Public Access UNIX and Internet at (503) 220-1016 (2400-14400, N81) = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 18 Jul 1994 13:43:42 -1000 From: mgraves@leadingedg.win.net (Michael Graves) Message-Id: <739@leadingedg.win.net> Subject: Re: profile for parafoil In article <30e85s$kh9@elaine.teleport.com>, Carl Crowell (crowell@teleport.com) writes: > >Question: How about a full size Giff or other format file to print out >in tiles so that you have an instant patern. > I would suggest a postscript file for smaller size and ease of use. Several of the folks around here have experience posting such things, perhaps they can offer technical assistance. Michael Graves = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Wed, 20 Jul 1994 13:45:56 -1000 From: rock@netcom.com (Anne Rock) Message-Id: Organization: NETCOM On-line Communication Services Subject: Re: profile for parafoil Simo Salanne (salanne@convex.csc.FI) wrote: : In <9407180700.AA18430@dagobert> malle@dbag.ulm.daimlerbenz.com : (Bernhard Malle) writes: : >Hello to all parafoil-experts, (and to all others) : >I have built a soft-centipede a la Peter Lynn, and now I am looking : >for a lifting device. I own already a flowform (from the rowland book) : ... : >Now I am looking for a good parafoil. I have got the book of : Bernhard, you don't let your sewing machine get rusted:-) I don't think the motor ever gets cold! Anne -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - * Anne Rock | * * rock@netcom.com | * * Berkeley, CA | * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =