monkeykites / no center strut
Posted: Mon Jan 15, 2007 10:06 pm
i haven't heard much about monkeykites (they seem to be more popular overseas) but recently discovered that their designer, saul griffith, works at squid labs, which until recently was two blocks away from where i work in emeryville.
a trademark of saul's designs is no center strut, like what north has decided to do for the 07 rhino. there's a really nice explanation of his quoted at this norwegian forum (third post down - just look for the english) in which he leads up to and describes why it's desirable to have no center strut. i follow it, right up to the point where he actually explains why it's better to have a higher distribution of ribs on the ends than in the center:
"This means that there is less air-pressure sucking the canopy into shape in the tips. That is why it is advantageous to put more of your ribs closer to the tips and closer spaced at the tips. So that is why we choose to have no central strut. By removing the centre strut, we can have more struts at the tips where they count more."
if the purpose of the ribs is to establish a preferred airfoil cross-section and prevent the canopy from getting sucked up away from that cross section by the low pressure above the kite as much as possible, then i would think that you'd want more ribs in the center, where the sucking was the strongest and thus the canopy will be distorted the most by it. perhaps he is talking about very low angles of attack (highly depowered), where the tips would have little, if any, lift, and the struts would be keeping their canopy from flapping the other way - downward/inward - rather than preventing it from being distorted upward/outward.
at any rate, it will be interesting to see what people find its effect to be on the rhino. the strut placement did strangely appeal to me when i first saw it.
a trademark of saul's designs is no center strut, like what north has decided to do for the 07 rhino. there's a really nice explanation of his quoted at this norwegian forum (third post down - just look for the english) in which he leads up to and describes why it's desirable to have no center strut. i follow it, right up to the point where he actually explains why it's better to have a higher distribution of ribs on the ends than in the center:
"This means that there is less air-pressure sucking the canopy into shape in the tips. That is why it is advantageous to put more of your ribs closer to the tips and closer spaced at the tips. So that is why we choose to have no central strut. By removing the centre strut, we can have more struts at the tips where they count more."
if the purpose of the ribs is to establish a preferred airfoil cross-section and prevent the canopy from getting sucked up away from that cross section by the low pressure above the kite as much as possible, then i would think that you'd want more ribs in the center, where the sucking was the strongest and thus the canopy will be distorted the most by it. perhaps he is talking about very low angles of attack (highly depowered), where the tips would have little, if any, lift, and the struts would be keeping their canopy from flapping the other way - downward/inward - rather than preventing it from being distorted upward/outward.
at any rate, it will be interesting to see what people find its effect to be on the rhino. the strut placement did strangely appeal to me when i first saw it.