readme.txt

Digital DATCOM Source Code and Examples

           THE USAF DIGITAL DATCOM

The files for this program are in the directory \atmos on the CD-ROM
    readme.txt      this file
    datcom.txt      instructions for use (to complement the manual)
    manual.pdf      a partial copy of the reference manual
    namelist.pdf    descriptions of the namelist data items
    datcom.f90      the main program
    datcom.exe      the executable, compiled with Lahey Fortran 95 v5.00d
    digdat.exe      the original executable from the USAF site
    source.zip      same as datcom.f90, but each subroutine is a separate
                       file. Archive in ZIP format.
    example*.dat    11 files, the sample cases from the document
    example*.out    output files for those cases which have run
                      as of the release date of the CD-ROM

You should make a directory on your hard disk and copy these files to
that directory. If you never use some of these languages, just erase
those files. You can always get them back from the CD-ROM.

Years ago, the USAF commissioned a project devoted to the idea of
documenting methods for estimating stability and control
characteristics of airplanes and missiles. The result was a big four-
volume document. This is the basis for this program. The government
document has been out of print for years, but there is a firm

       Global Engineering Documents
         15 Inverness Way East
           Englewood, CO 80112 USA

that offers copies. As of 1 January 1999, their price was $175
You can visit them at http://global.ihs.com   and purchase online.
Or send e-mail to [e-mail]

A natural development of this project with its printed charts and tables
was a computer program that would do the table lookup and interpolation
that was time-consuming and error prone. The result was the program known
as digital datcom.

You can download the original code for this program from a server at
Wright-Patterson. Contact Bill Blake ([e-mail]
for detail or search for the appropriate web site. You can also order
the manual from NTIS (703-487-4780) by asking for document ADA-086557.
I did this and found the quality of the document so poor, that I have
spent some time creating a good copy of this document that I have
included on the CDROM.
Unfortunately, I cannot call it a complete copy at this time, but I have
had pretty good luck scanning the document and using OCR to make it
into a Word Perfect document. From there, I made a PDF file that is
included on the disc (manual.pdf).

In contrast to last years disc, the executable this year seems pretty
solid. I thank Lahey for the latest version of Lahey Fortran 95, v5.00d
for handling legacy code much better that anything on the market in
January 1998. It is still true that this is a dangerous code with all of
its non-uniform lengths of common blocks and GOTOs that jump into the
middle of DO loops. You must be sure to use the -nf95  and -nchk flags
when compiling or you will drown in error messages.

I have left the digdat.exe file that you can download from the Air
Force site on the CD-ROM, but almost everyone who tried it last
year had nothing but trouble. Including me.


PROJECT SUGGESTION - It would be very useful to have a Datcom to LaWGS
conversion program that created a wireframe model from a Datcom input
file. The program WB2WGS could be used as a guide.