Article 27578 of rec.kites: Newsgroups: rec.kites Path: tug!andrew From: andrew@tug.com (Andrew Beattie) Subject: Re: Chevron progress Organization: /usr/lib/news/organisation Date: Sat, 13 Jul 1996 07:50:23 GMT Message-ID: References: <9607100941.aa03230@tug.com> <31e66492.262816@news.knoware.nl> pdjnjvt@knoware.nl (Peter de Jong) writes: >I'm not sure what you mean by stalling. There seem to be three stalling problems: 1) AOA ~= 90 degrees Kites seem to cope with this much better than I would theorise. 2) AOA ~= 0 but windspeed too low. This is the problem I was asking about. 3) AOA < 0 Another serious problem. >A common flying machine has a very limited range in the angle of >attack: it starts, flies and lands horizontally. They also have a very limited windspeed. Maybe a single seater flies between (guess) 100mph and 200mph. That's a hell of a lot easier to design for than the 0 - 50mph that we must consider. They don't realise how easy they've got it. >( Found some parawing airfoils that look a lot like the Quad Comp >profile: very promising ) *giggle* Methinks that maybe the QComp looks err... a lot like a peraglider profile... >Normally, you would give the wing some washout to decrease stalling. >Knowing you are using a kind of Sput profile (a symmetrical naca) it >seems to me that this is no option because when the aoa should get >negative during normal flight the section will get a negative lift and >the tips will collaps inward. My profile, while derived from the S-4, is no longer symetrical. This is one of the reasons. Note that at a negative AOA, the profile changes shape slightly, because it is held purely by the rib and not altered by bridle tuning. >Another thing is bridling. The longer the primary bridle is the harder >it is for the kite to adapt to changing conditions. IMO your best bet >with an given profile is to try to make the primary as short as >possible. Yes. In particular, it can adapt to very low AOA by letting the tail up. Andrew -- This message contains a restricted munition. Export from the USA is illegal. #!/bin/perl -sp0777i