Date:	Thu, 28 Jul 1994 10:50:31 -1000
From:	peterr@gds.nl (P. Ruinard)
Message-Id: <1994Jul28.205031.17662@gds.nl>
Organization: GDS BV, PObox 473 Delft, The Netherlands..
Subject: Stunt Kites II Kite format

Dear Carl (Crowell) and Andy (Hawken) and others,


I would like to respond to the discussion going on about the 
kite file format.

I am the author of the plotfoil program supplied on the disk 
belonging to the Stunt Kites II book. (I did not invent any
of the kites, this work is done by Servaas van der Horst and
Nop Velthuizen)

I would like to respond to the following points:


> Does anyone know anything about the format used in Stunt Kites II ?

The Stunt Kites II file format is a file dramatically stripped 
version of the Postscript language.

   The commands used are:
      Bounding box
      Move
      Line
      Curve (Bezier)

This small set is enough to define and plot a plan of a kite,
the bezier function is needed because all stuntkite models 
supported have curved sails.


>  I guess that is has a plotfile program to plot aerofoil 
>  profiles by splining a serise of points to form a curve.

This is one of the steps involved, what I do is:
   -  Enter the coordinates of the map in a textfile
   -  Transfer them to a CAD program that eats the text
      and spits out a 'drawfile'
   -  This drawfile is edited in an object orientated drawing
      program
   -  Export it in the programs own postscript format (this
      step reduces the output to the commands above)
   -  Remove not needed information
I do this work on an Acorn Archimedes computer so I shall
not bother you with the names of the programs needed.

In the plot program on the 'KITE 1.0' disk are, amongst others,
options to alter X and/or Y size of the plans provided.

The reason for using a subset of the Postscript language is
that it is very easy scaling up or down the plan in my own plot 
program using the postscript coordinates.
It is even simple to alter the X and Y scaling factor of
curves independently (syntax ?).


> I dont think that any of the other patterns are 
> included on the disk.

Currently the following plan are supported:
    TEST:
      A testfile containing a circle in a square. Printed
      on paper the circle should have a diameter of 24 cm. 
      The big square measures 24 cm; the little squares 12 cm. 
      If all functions well, this Test is printed on 2 sheets of A4. 
    SPUTNIK 3:
      Sputnik 3 profile with default size of 95 cm. 
    SPUTNIK 4:
      Sputnik 4 profile with default size of 95 cm. 
    KRYPTON-S:
      Krypton-S profile with default size of 95 cm. 
    SPUTNIK 1:
      Template for Sputnik 1 & 2 profile (STUNT KITES I) with
      default size of 60 cm.
    SPEEDFOIL:
      Template for Speedfoil profile (STUNT KITES I page 74), 
      default size 45 cm.
    ZIPP:
      Templates for small 3panel Zipp 
    MEDIUM ZIPP:
      Templates for 180 cm wingspan 8panel Zipp 
    BIG ZIPP:
      Templates for 240 cm wingspan 6panel Big Zipp 
    SPEEDWING:
      Templates for large 5panel Speedwing Super with camber.
      'Speedwing super pro'
      
Also on the the disk is a program written by me that allows you
to alter about every variable needed for building Sputnik 3, Sputnik 4
and Krypton-S. These kites are Peel like kites (great for buggy's;
I use the 5,2 square meter version).
It allows you to alter, wingspan, wingshape, bridle, area, etc. 
The measurements of the kite are printed. 
Also are the scaling factors given so that you can print the profiles 
using the plot program.
 
 
> I think that SK II has a companion disk (to purchase separatly).

Yes, although it is mentioned in the book, it is not supplied 
with the book. In Holland the disk costs about 20 guilders.


If you anymore questions, please feel free to contact me.

   Peter Ruinard
   peterr@gds.nl
   



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