Date: Sun, 26 Jun 1994 23:34:03 -1000 From: chill@wv.mentorg.com (Chris Hill) Message-Id: <2um6eb$kun@hpbab.mentorg.com> Organization: Mentor Graphics, European Technical Centre Subject: Flexifoil stack and power Thanks for the net.wisdom, generated from my last post regarding my observation that the pull generated by a single flexi I was flying being more than doubled when a second was stacked. As I was flying in a fairly low wind I can only suggest that putting the second flexi in the stack caused the speed of the whole to increase and thus increased the total power, hence my observation. -- Chris_Hill@mentorg.com Mr Paranoid sends me messages, he says that THEY have taken over my employers; I fool them by disseminating my own opinions! = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Thu, 30 Jun 1994 23:45:32 -1000 From: ces1at@surrey.ac.uk (Andy Tate) Message-Id: Organization: University of Surrey, Dept Chem & Proc Eng,UK Subject: Re: Flexifoil stack and power In article <2um6eb$kun@hpbab.mentorg.com> chill@wv.mentorg.com (Chris Hill) writes: >From: chill@wv.mentorg.com (Chris Hill) >Subject: Flexifoil stack and power >Date: 27 Jun 1994 09:34:03 GMT >Thanks for the net.wisdom, generated from my last post regarding >my observation that the pull generated by a single flexi I was >flying being more than doubled when a second was stacked. >As I was flying in a fairly low wind I can only suggest that putting >the second flexi in the stack caused the speed of the whole to increase >and thus increased the total power, hence my observation. >-- > Chris_Hill@mentorg.com > Mr Paranoid sends me messages, he says that THEY have taken over > my employers; I fool them by disseminating my own opinions! Similar things in the boating world. The foresail or jib increases the speed of flow of air over the rear of the main sail and hence its lift. So maybe the second flexi has simialar effects. Andy.... _____________________________________________________________________________ Dr Andrew H.J. Tate /\ Computer, Control & Instrumentation Support, \/ Dept of Chemical & Process Eng, / University of Surrey, Q / Guildford, Surrey GU2 5XH Tel: +44 483 259515 (&V32bis) |-+/ Fax: +44 483 259510 / \ Go fly a kite ! It's fun. Email: ces1at@surrey.ac.uk __________-_-_-_-______________________________________________________________________________ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Wed, 6 Jul 1994 11:54:32 -1000 From: lord@eskimo.com (David Lord) Message-Id: Organization: Eskimo North (206) For-Ever Subject: Re: Flexifoil stack and power My experience with flexifoil stacks is that with two you get less than double the pull you got with one. And with each one you add you lose some more. The per kite pull with two is greater than the per kite pull with three. The greater the separation between the kites the less loss. When stacked each kite creates some turbulence for its neighbor and causes this loss in pull. Allthough I have not made measurements I am reasonably sure that the more kites you put in a stack the slower the group flys. Since getting a buggy I have a renewed interest in flexi stacks and maybe I can get around to making some measurements. BTW it is fun to fly one or more flexi's in front of two line deltas. It works best on kites that have the bridle points far apart such as a TOL Team kite or a 10 ft size delta. I have added a single flexi in front of a Quadrifoil 25 to pull a buggy and it works pretty good. Do not try more than one though, because as you launch a stack of flexi's they do a lot of bucking before they lock in and they invariably tangle in the lower lines of the Quadrifoil. Dave Lord = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =