Boat Design Forums  |  Boat Design Directory  |  Boat Design Gallery  |  Boat Design Book Store  |  Thanks to Our Site Sponsors

Go Back   Boat Design Forums > Design > Sailboats
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #136  
Old 12-04-2009, 07:43 PM
Doug Lord's Avatar
Doug Lord Doug Lord is offline
Flight Ready
 
Join Date: May 2009
Rep: 919 Posts: 5,604
Location: Cocoa Beach, Florida
This is an asymetrical section(from skywalk site) kite shown in the orientation it would have on a performance boat.The top and bottom of the kite as shown would be supported entirely differently than shown and the lines going to the center of the kite wouldn't be necessary. Since the kite is an asymetrical wing the problem is how to use it on opposite gybes:
Attached Thumbnails
Lifting Spinnakers:does it lift the bow?-sky-walk.jpg  
__________________
yes, it is a revolution
---"So (yet) another new world begins." Seahorse 2011
My Gallery: http://www.boatdesign.net/gallery/sh...0&ppuser=31218
Reply With Quote
  #137  
Old 12-04-2009, 07:45 PM
bistros bistros is offline
Previous Member
 
Join Date: Jan 2007
Rep: 0 Posts: 534
Quote:
Originally Posted by Doug Lord View Post
This is an asymetrical section(from skywalk site) kite shown in the orientation it would have on a performance boat.The top and bottom of the kite as shown would be supported entirely differently than shown and the lines going to the center of the kite wouldn't be necessary. The problem I mentioned above remains:
Again, Doug you are completely off base and substituting conjecture for facts. The middle suspension lines are critical to maintaining the airfoil. I've been suspended under a similar inflatable foil section hundreds of times and if the middle lines were removed, I would not be walking (or alive) today. An inflatable airfoil section section works because of evenly spaced lateral shroud lines, even in orientations such as in the picture you show. Each vertical cell wall in the inflated foil needs a suspension line to control it's placement.

In a inflated foil section, the full width of shroud lines provide the same function as mast track or luff wire in a sail - without a luff rope, a main sail would not work, and without a rigid forestay and hanks or internal luff wire, a jib would not be effective. Just attaching head and foot (tack & clew) would not work.

If you doubt this, please refer to Dan Gardiner's reference work "The Parachute Rig", to understand the issues with inflatable wing sections. I was a FAI-licensed Rigger "A" for parachute reserve packing and equipment design and maintenance during my years of skydiving.

--
Bill

PS

If you want to learn more about this, either go across Florida to Zephyrhills (north of Tampa - a major skydiving Mecca) or up the coast to Deland (the other major dropzone in Florida. I've spent weeks there and there are people there who will happily explain inflatable wing theory to you.
Reply With Quote
  #138  
Old 12-04-2009, 07:49 PM
Doug Lord's Avatar
Doug Lord Doug Lord is offline
Flight Ready
 
Join Date: May 2009
Rep: 919 Posts: 5,604
Location: Cocoa Beach, Florida
The whole subject IS conjecture-is this kind of a thing possible or not? You say no without fully understanding the implementation that may be possible.
I've spent many hours watching kiteboards up close and I think something along these lines MIGHT work....
It is obvious to me that the shape of the kite is directly influenced by the direction of pull of the lines-my idea is based on having the support lines support the ends entirely differently than the way the ends are supported as a kite.
Perhaps using the 4 line "C" design with mods necessary to produce an asymetrical section gybe to gybe.

http://www.kiteboardingevolution.com...ding-kite.html
__________________
yes, it is a revolution
---"So (yet) another new world begins." Seahorse 2011
My Gallery: http://www.boatdesign.net/gallery/sh...0&ppuser=31218
Reply With Quote
  #139  
Old 12-06-2009, 08:11 PM
Munter Munter is offline
Amateur
 
Join Date: Jul 2007
Rep: 100 Posts: 223
Location: Australia
Doug - you've just re-invented Peter Lynn's kite design! (sort of)

Get googling for details.
__________________
Cole 43 Rumrunner II - An Australian classic

My home efficiency/renovation blog
Reply With Quote
  #140  
Old 06-30-2010, 12:05 AM
ned ned is offline
Junior Member
 
Join Date: Apr 2010
Rep: 16 Posts: 33
Location: New Zealand
gennakers deffanatly lift the bow.
Reply With Quote
  #141  
Old 06-30-2010, 01:14 AM
Munter Munter is offline
Amateur
 
Join Date: Jul 2007
Rep: 100 Posts: 223
Location: Australia
Quote:
Originally Posted by ned View Post
gennakers deffanatly lift the bow.
Ok. Well I guess that's the end of the discussion then.
__________________
Cole 43 Rumrunner II - An Australian classic

My home efficiency/renovation blog
Reply With Quote
Reply



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Lift and drag theory DSmith Sailboats 9 09-29-2006 01:34 PM
can you have too much lift? capt'n ron Boat Design 4 09-11-2005 07:44 AM
Lifting a Deck steveo Fiberglass and Composite Boat Building 2 03-10-2005 08:18 AM
ajustable lift keel OrionsSword Sailboats 10 01-03-2005 03:25 PM
Spinnakers barbdwirenroses Sailboats 2 08-11-2004 09:24 PM


All times are GMT -5. The time now is 04:21 AM.


Powered by: vBulletin Copyright ©2000 - 2012, Jelsoft Enterprises Ltd.
Web Site Design and Content Copyright ©1999 - 2012 Boat Design Net