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PostPosted: Wed Aug 07, 2002 3:35 am 
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yes I know you have to pull the bar !, but can someone point me to a page or give me an aerodynamic explanation of the turn. I think the tip on the inside of the turn just stalls, but I'm not sure. An engineering explanation would be nice. 2 line kites seem to steer in a different way.


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PostPosted: Wed Aug 07, 2002 1:01 pm 
Dear Captain Pugwash, you pull the bar with your left hand and the kite goes left, to pull the bar with your right hand the kite goes right, hope this has been a help!
Head of Engineering, Cambridge University Neophysics Technical Section


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PostPosted: Wed Aug 07, 2002 10:23 pm 
Dear captain pugwash.. don't know but I'm sure its easier than steering the black pig which involves Captain Pugwash at the helm yelling at Master Bates to give him quick pull, avoiding Sea man Stains and figuring out when he has time to go down stairs and Roger the Cabin boy.


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PostPosted: Thu Aug 08, 2002 1:15 am 
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73 people have read this question and I get two dumbfuck replies....is the entire kiteworld ignorant of how things actually work on their kites


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PostPosted: Thu Aug 08, 2002 3:05 am 
ask a "dumbfuck" question...
the truth is no one really cares why their kite turns just so long as it does...
but if you want to know, why don't you go and fly your kite and observe
U will find that its all about the twist and not the pull(something that luckily my chick is well aware of)


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PostPosted: Thu Aug 08, 2002 3:45 am 
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let me guess, you turn the key to your car and hey-presto "it just starts". Hey, the simple approach to life suits simple people QED.
As for us BScHons engineers who design cars and pilot aircraft we actually like to know the "WHY" it often helps to make things better.
Have a simple life...we'll work out the difficult bits for you !


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PostPosted: Thu Aug 08, 2002 4:45 am 
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Location: www.tbks.net FL
Here now!! Play nice kiddies!
Good answers will usually not be obtained here by referring to people and or posts as "dumbfuck" Pugwash, just so as that you know.

I'm not so sure their is a real technical answer to your question. Pull right and it goes right becaue it changes the shape of the kite, thus causing one side to slow down(stall), which causes the other, faster flying side to fly over the slower wingtip. Pulling right on your control bar is like hitting the brakes on the right side of your kite. Traditionally, 4 line kites have always been flown with handles, allowing more direct control of applying the brakes to the wingtips...you could slow one tip and turn the kite or you could stall both sides at the same time if you wanted. By moving to the control bar method, it's easy to lose focus of how it's working because the front lines come together as one at the bar. It's basically still alot like how the handles work to control the kite except you can only apply the brakes to one side of the kite at a time....aside from a little sheeting action. If you were to take a 4 line kite flown by handles, and attached the handles together as one, end to end, with the front lines closest to center(sorry if that's not real clear), and the brake lines at the ends of your newly formed 'bar',(trying to draw what I mean.... l___l_l___l ...like that) you would have the same effect as we use now with the inflatables except your front lines would come down to the bar side by side as opposed to becoming one, but because they would be so close to the center(pivot point), it would be about as if they were one...you can turn the bar either way, thus applying brakes to one side at a time, which makes for simpler controlling, but you can now only apply the breaks to one side at a time as opposed to the control you had to each side at the same time before you joined the handles into a bar. I hope that some of that rambling added up to something for you.

The way a kite turns can also be relevant to the power it produces while it turns. If one of the kites wingtips stalls to the point of allowing the kite to almost pivot around a point, it will have less power through the turn than a slower turning kite that has some forward speed as it swoops through the turn. This can be seen by flying a foil set up with 4 lines going to 2 handles. If you were to control that kite in such a manner as to make it set and spin in the sky, it would produce significantly less power than it does when it is moving forward through the sky. Most of the lift and pull are generated by the kite moving forward through the sky. So as they achieve the ability to make inflatable kites turn faster, it also becomes important to find the right balance of turning speed and forward movement through the turn to maintain a good constant pull throughout the turn.

I'm pretty sure that I not also strayed from your original subject a little, but I too proabably have failed to give you a suitable answer...but I tried, in the least 'dumbfuck' way that I could. If you really wish to find some aerodynamic explanations of a more technical sort than I have given you, you may have better luck researching paragliders and or parachutes. They have been produced longer and probably have easier to find technical data because of that, than kites do today. And they too are basically kites, and are turned by the same principle of stalling one wingtip.

Johnny


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PostPosted: Thu Aug 08, 2002 5:20 am 
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To Johnny : THANKS

The dumbfuck remark was aimed at anonymous because myself and a few mates post irregluarly here and have found a regular 'anonymous' who likes to be less than helpfull.

The kite thing isn't as simple as most think. I fly competition stunt foils and have flown 2handle 4line power-foils. I have a good idea how they turn and it agrees with your knowledge. Parachutes and paragliders just collapse the wing on one side loosing lift resulting in a turn

The inflatables are quite different...I have tried to simulate them on windtunnel software simulators but without success.
The leading edge bladder section buggers up the airflow on the underside.

I also fired a couple of mails off to the designers but they didn't reply.

From an engineers point of view I look at the design and it just doesn't work well aerodynamically, so either I'm wrong or we're all being had by the designers....I would suggest that I'm wrong, but I'd like to know why.

Did it ever strike you as strange that 2line inflatables use the cross line on the bridle to pull the opposite edge 'in' on a turn ?

Anyway thanks for the help


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PostPosted: Thu Aug 08, 2002 5:41 am 
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Hey Captain,
the more I think about it, the more I follow what you are saying. Their does appear to be a differnce with the inflatable design, but I think it is in it changing it's shape and thus causing it to pull one way or the other. I don't have the answer for you, but I will be more than happy to get you an answer from a designer, as I like you, feel that knowing how and why your plane flies makes you a better and safer pilot as opposed to just knowing how to make it fly. I'll give a designer a call tomorrow(too late today) for you and let you know what I find out.

Johnny

<font size=-1>[ This Message was edited by: Johnny TBKS on 2002-08-08 06:43 ]</font>

<font size=-1>[ This Message was edited by: Johnny TBKS on 2002-08-08 06:44 ]</font>


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PostPosted: Thu Aug 08, 2002 5:54 am 
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I wanted to add without editing my message for a 3rd time that I don't think that your airflow design software is lieing to you. I don't think it's any big secret that the leading edge is far from a perfect streamline surface for the air and that it does in fact screw it up. JoJo is well aware of this I think as they are working with the 'Hype' to produce a kite with another skin coming from the leading edge, but not necessarily all the way down to the tail of the kite. Have you tried this on your software? I'd ve interested in the results if you have. And if you havent, can you? Add another skin to the leading edge and taper it down to the canopy on the underside, maybe at varying lengths, thus making the rear side of the bladder shaped more like the rear side of a wing as opposed an innertube.

Later

Johnny


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