Date: Mon, 8 Aug 1994 04:52:45 -1000 From: RODGER@ray.uct.ac.za (Rodger Duffett) Message-Id: Organization: Division of Applied Sciences, Harvard University Subject: Parafoil Bridling? Hello Everybody Well in just a weeks time I will be leaving the skies of Cape Town and heading for Kuantan, Malaysia to fly in a festival there with the rest of our little team. We are looking forward to learning a lot! I have made a leatherback turtle (in ripstop;->) based on parafoil type design which I am intending to take with. Turtle really looks great and inflates well when sent up behin another kite or held in the wind. I am struggling to bridle him so that he flies unaided. What are the design considerations for bridling of low aspect ratio parafoils? For example where should the attachment points of the bridle be on the kite? Is it essentail to use flairs? - for aesthetic reasons I would like to try and avoid this and just have little loops on the kite. What angles etc... Bye for now = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 8 Aug 1994 02:46:42 -1000 From: bernhard.malle@dbag.ulm.daimlerbenz.com (Bernhard Malle) Message-Id: <9408081246.AA13699@dagobert> Organization: Division of Applied Sciences, Harvard University Subject: Re: Parafoil Bridling? Hi, I forgot the question about the fins. The fins at a parafoil gives you stability to the sides. They are considered a must for a parafoil or a flowform. That's also why you do not need them with steerable parafoils like the peel, the flexifoil or the paraflex. However, if you look at the inflatables of Peter Lynn, you will never find fins. Peter uses drogues in different forms and sand weight. I have seen a clever mechanism in his gecko, were he used a zipper at the tail to fill in sand. At the wind conditions at Fanoe 94, the gecko was bouncing around so that the only thing that helped was to fill in loads of loads of sand into the tail of the inflatable. Drogues: Peter not always uses drogues that are recognizable at first glance. He uses them on the small octopusses and the killer whale (there he even uses four of them). With the big octopus and the manta-ray, for example, he uses a very long tail, i.e. the tentacles of the octopus have the function of a tail. Smooth tails Bernhard +------------------------------------------+ | Bernhard Malle | | Bernhard.Malle@dbag.ulm.daimlerbenz.com | | Ulm, Germany | +------------------------------------------+ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 8 Aug 1994 02:27:44 -1000 From: bernhard.malle@dbag.ulm.daimlerbenz.com (Bernhard Malle) Message-Id: <9408081227.AA13493@dagobert> Organization: Division of Applied Sciences, Harvard University Subject: Re: Parafoil Bridling? Hi Rodger, (? name was not clear from the message) > Turtle is made in predominantly black ripstop. He has a green head > which seems to move realistically from side to side when he is towed > behind my Tri-D. His body is a 4 cell shield shaped parafoil with > turtle shaped fins and tail. His front fins are spread out using a > 3mm glass fibre rod. His head is kept open using 2mm glass rods. The > present version is about 1.5m long and 1.2m wide including fins etc Spars in an inflatable, hmmm... :-) When I made my octopus, I did not have any hint about the bridle. I choose the bridle points nearly randomly and attached a 3m bridle line to each point. I organized the bridle lines in two groups - one right, one left. Then I connected the right group to a bridle ring and the left group to a bridle ring. I used the prusik knot to attach each bridle line to the bridle ring. I am not good in explaining knots - it is a knot that you can very easily slide back and forth on another line, so that you can easily adjust the length of the lines. (You should find a description of the knot by Anne and one by Simo in the archives) Then I hang the bridle rings on the ceiling in my living room, shortly in front of the head of the octopus (this should assure the right angle of attack). Next work was to adjust all the bridle lines so that they were all tight. Then I tried it on the flying field. The angle of attack at my octopus can be choosen between two different extreme cases: either too upset, then it will not have enough lift and stay at the ground, or too flat, then the head of the octopus with the air-inlet will collapse. I have not yet found an satisfactory way to avoid changing all 24 bridle lines when I just want to change the angle of attack by 1 or two degrees, it is always a time consuming task. Additionally I have to take care, that the right and the left side are the same.... Hope this helps! > > Once I have got him bridled and flying I will see if I can organise a > picture for the archives. If there is interest I will refine the > design and send it through as well. Please do so! smooth bridling Bernhard = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =