View source for Sled Kite Construction

[[File:SledKites.png|800px|right]]
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=====Description=====

[http://en.wikipedia.org/wiki/Scott_sled '''Sled Kites'''] are suitable for most wind conditions but best in steady continuous breezes. They can be distinguished by having their canopies supported only longitudinally either with spars, air filled tubes or simply folds in the canopy material.


=====Design History=====

A '''Kite''' of this general design, with 3 spars tapering together towards the base, was patented as a 'Polymorphic Kite' by Canadian born William M. Allison in 1956. Later, a version with 3 parallel spars and a stabilising vent hole at the tail was marketed by a Frank H. Scott in the early 1960's when it acquired the now common name of [http://en.wikipedia.org/wiki/Scott_sled '''Scott Sled'''].


'''Sled Kites''' are easy to make fly but can be vulnerable to cross-winds causing them to collapse with little or no chance of recovery. In 1979 John W. Loy filed US Patent 4279394 for a '''Swallowtail Kite''' which attempted to overcome this by having the central spar create a protruding leading edge. 


Designs have continued to evolve with 2 spar versions now more common. In the early 1970's, kite designer Ed Grauel introduced the idea of vented kites and later, '''Sled Kites''' were developed with inflated canopies and spars replaced by tubes of canopy material inflated by the air pressure. Modern [http://en.wikipedia.org/wiki/Foil_kite '''Foil Kites'''] may be considered an extension of this idea.


Some general proportions and a basic method of construction is shown opposite. Experiment with Proportions, 2 or 3 Spars, Leading and Trailing Edge shapes, Vent designs and addition of Tails ''(you will need to press '''Return''' after each change of value)''.

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[[File:AngleofAttack.png|150px|right]]
<span style="color: green">'''Note:'''
Once you have finalised your '''Kite''' proportions and general design, the '''[[Kite Design Basics|Angle of Attack]]''' can be set by adjustment of the '''Bridle'''. The normal method is to loop the '''Bridle''' over one finger and suspend the '''Kite''' upside down. The position of the finger is adjusted until the tail of the '''Kite''' hangs at an angle of 20<small><sup>0</sup></small> to 30<small><sup>0</sup></small> to the floor. </span>


<span style="color: green">Once the '''Bridle Point''' has been determined in this way, loop a '''Bridle Line''', about 8 times the length of the '''Spars''', between the two points and attach the '''Flying Line''' to its centre. </span>


<span style="color: green">See the '''DT Online''' article on '''[[Kite Design Basics]]''' for more information about the forces acting on a kite and how to use tails or drogues to balance them.</span>
  
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=====Materials and Construction=====

'''Kites''' can be made quite successfully using thin '''[[Basic Kite Construction|Polyethylene]]''' sheeting ''(e.g. as used to make bin liners)'' and '''[[Adhesive Tapes]]''', split '''[[Basic Kite Construction|Bamboo]]''' flower sticks. '''[[Paper and Card|Kraft Paper]]''' can also be used and even '''[[Paper and Card|Tissue Paper]]''', especially for smaller '''Kites''' and using '''[[Basic Kite Construction|BBQ Skewers]]''' for '''Spars'''.


More sophisticated '''Kites''', and most commercially available '''Kites''', use '''[[Basic Kite Construction|Ripstop Nylon]]''' or similar,  together with '''[[Basic Kite Construction|Fibreglass Rods and Tubes]]'''. Instead of fixing with tape, extra allowances are added to the '''Kite''' pattern where needed, to enable the '''Spars''' to be slotted into sewn hems.


See the '''DT Online''' article on '''[[Basic Kite Construction]]''' for more detail.


{{Packaging Designer Guide}}
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<span style="color: green">'''Note:'''</span>
* <span style="color: green">The main variable in the table below is the total length of the '''Kite Spar''' ''(set initially to 1200mm)</span>.
* <span style="color: green">Almost all other dimensions are derived as a '''Percentage of the Spar Length''' ''(e.g the total '''Width''', the variable  <<span style="color: red">MaxWidthPercent</span>>, is set initially as equal to the variable <<span style="color: red">SparLength</span>> - or 100%)''</span>.
* <span style="color: green">'''Parallel Spars''' are generated by setting the variable <<span style="color: red">BottomWidthPercent</span>> to be equal to <<span style="color: red">TopWidthPercent</span>>.
* <span style="color: green">Note that either numbers or <<span style="color: red">variable names</span>> may be typed in to alter kite proportions</span>.
* <span style="color: green">You will need to press '''Return''' after each change of value</span>.
* <span style="color: green">All '''Percentages''' initially are based on the proportions given at the start of this article but all can be changed by clicking in the table and typing in a new '''Percentage''' ''(e.g. the Leading Edge can be straightened by setting the variable  <<span style="color: red">BridleTopPercent</span>> to zero or made pointed by setting to a minus number)''</span>.
* <span style="color: green">Refreshing or reloading the page will reset all variables to their default values.</span>.

See '''[[Packaging Designer User Guide]]''' for further information.

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<dtapollonius dwg="/images/2/28/Kite_sled.txt"></dtapollonius>


=====Sled Kite Examples=====

* William M. Allison's 1956 Flexible Kite patent, US2737360, ''(aka the (original) Sled Kite)''.
* See below a home-built14ft "'Scott Sled"' kite made from clear polyethylene sheeting reinforced with '''[[Adhesive Tapes|Duct Tape]]''' and 2" x !" softwood '''Spars'''. 
* A range of commercially produced '''Sled Kites''' are available from Amazon.
* US Patent 4279394 for a '''Swallowtail Kite''' filed in 1979 by John W. Loy. 


{|
|-
| [[File:AllisonPatent.png|thumb|William M. Allison's 1956 Flexible Kite patent|link=http://kitepatents.blogspot.co.uk/2006/07/allisons-sled-us2737360.html]]
| [[File:ScottSledKite.png|thumb|Home-built Scott Sled Kite|link=http://www.geocities.ws/potatotrap/tech/bluetarp.htm#kites]]
| [[File:RamAirSledKites.png|thumb|Sparless Sled KItes|link=http://www.amazon.co.uk/gp/product/B001LQ9ZU8/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=B001LQ9ZU8&linkCode=as2&tag=dton06-21]] 
| [[File:SwallowTailSledKite.png |thumb|1979 Patent Swallowtail Sled Kite|link=http://en.wikipedia.org/wiki/Kite_types#/media/File:USpat4279394SwallotailslepByLoy.jpg]] 
|}


{{Kite Materials Buyers Guide}}



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