README file for the "rang" boomerang simulation package.
Last edited: Sun Nov 11 17:32:30 1990 by jco (Dumpmaster John) on reef


PEDIGREE

This boomerang flight simulation program is a port of an IBM-PC BASIC
version.  Here are the comments that applied to the BASIC version:

	The algorithm that calculates the flight path of the 'rang was
	written by Gerhard Bertling of Berlin, West Germany.

	John Mauro of Richland Virginia, contributed some user friendly
	ideas.

	The rest of the program was written by Jim Martellotti of Tustin,
	California. (714-544-2005)

The program was translated to SunOS and the C language by John C. Ortheofer
(jco@reef.cis.ufl.edu) and Brian Bartholomew (bb@math.ufl.edu).  It produces
output designed for use by the GNUplot program.

The GNUplot package may be ftp'ed, free of charge, from prep.ai.mit.edu.  It
works on many, many platforms, including Sun, MS-DOS, and DEC VAX machines.


NOTES ON OPERATION

Here are some notes that apply to the operation of the C language version:

	o The user interface has been changed from menu-based to
	  command-line.  Use "rang -help" to discover what options are
	  available.

	o The "mode" parameter switches between output screen formats.  Zero
	  (0) gives you a full-screen 3D perspective of the flight, and one
	  (1) gives you a 4-way split screen, containing projections of X,
	  Y, and Z, and a smaller 3D perspective.

	o The user-parameter error checking has been removed.

	o The program now outputs GNUplot directives, instead of using the
	  BASIC graphics library.

	o Various numerical accuracy improvements have been made; the
	  program now runs in double precision, and the value of Pi has been
	  improved.

	o Variable names have been expanded somewhat for readability's sake.
	  More internal documentation has been added.

	o The use of GNUplot has enabled many more output possibilities,
	  including Postscript.


BUILDING INSTRUCTIONS

Here are some program building instructions.  We hope they are useful for
your system.

	1. Uncomment the VMS option in the Makefile, if you are running VMS,
	   and comment out the UNIX option.

	2. You may choose to uncomment the CC option to use the GNU C
	   compiler, but this is optional.

	3. On UNIX, do a "make depend ; make".  This will build the program
	   "rang".


"SERVING SUGGESTIONS"

	% rang > tmp ; gnuplot		# run with the defaults

	% rang -help
	rang: illegal option -- h
	Usage:  rang [-v velocity] [-a aim] [-t tilt] [-l lay_down] [-e elevation]
	        [-m mode]
	Defaults: velocity  =  32.000
	          aim       =  15.000
	          tilt      =  10.000
	          lay_down  =   7.000
	          elevation =  30.000
	          mode      =   1

	% rang -a 30 > tmp ; gnuplot


FOR FURTHER READING

We have made a literature search through a wide cross-section of scientific
journals, back to the year 1968.  This information is included in the file
rang.bib.  On a UNIX system, you may be able to use the command:

	roffbib rang.bib | lpr	

To print this out in a nicely-formatted fashion.


WISH LIST

We are currently trying to discover the proper lay_down value and range of
velocity values that apply to the Aerobie(c) Orbiter boomerang.  If anyone
can suggest a non-experimental method to determine the lay_down parameter,
we would be grateful.  We want to expand the model to allow a negative aim
angle, as suggested in the Orbiter(c) instructions.  We want to add a
constant wind, modeled as a gradient from ground zero upwards.

If Alan Adler is out there reading this, how about sending us some *real*
boomerang modeling software?
