Date:	Tue, 23 Jan 1996 06:49:00 -1000
From:	cyuen@rci.rogers.com
Message-Id: <96Jan23.175236est.20757@janus.rogers.com>
Organization: Division of Applied Sciences, Harvard University
Subject: # of ribs in Sputnik


To Sputnik makers everywhere:

I've noted that all of the designs in SKII are based on 36 ribs.  Being a 
generally lazy sort, I prefer to work with 24.

Now in the theory part of SKII, it is mentioned that having too wide a cell 
for the size of the kite will affect the performance due to the billow of 
the cells effectively causing a different profile in flight.  Logically 
then, I would want to narrow the rib profile to compensate for this, say 
>From 17> 15  Has anyone explored this?

Regards,

Cal Yuen (cyuen@rci.rogers.com)
Vancouver BC Canada
Aoxo <- El Mirage/BBT2 -> moxoa

 


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Date:	Wed, 24 Jan 1996 09:04:13 -1000
From:	andrew@tug.com (Andrew Beattie)
Message-Id: <DLp8z2.G78@tug.com>
Organization: /usr/lib/news/organisation
Subject: Re: # of ribs in Sputnik

cyuen@rci.rogers.com writes:
>I've noted that all of the designs in SKII are based on 36 ribs.  Being a 
>generally lazy sort, I prefer to work with 24.
>
>Now in the theory part of SKII, it is mentioned that having too wide a cell 
>for the size of the kite will affect the performance due to the billow of 
>the cells effectively causing a different profile in flight.

It is correct that changing the number of ribs will change the performance
of the kite.  Whether this change is beneficial or detrimental depends upon
your aims.  When building large kites, I prefer a fatter profile, to
increase the coefficient of lift at low speeds (because I know that a
big, low-wind kite won't be going all that fast in the first place).

Currently, I'm building 7m^2 and above with 24 cells *and* a slightly fatter
rib (18) to achieve this aim.  If, however, you *want* Nop's thin profile,
then I would advise that you stick with the 36 rather than go to a narrow
rib on 24 cells.  If the rib is narrow in relation to the width of the cell,
you have a hen the rib has very little effect on the shape of the skin...

Andrew
-- 
I lost a reel of 150lb Spectra (unflown, unsleeved, nearly 1000' of
it on a white reel) at El Mirage.  If it ended up in your bag, please
drop me a line.


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