(word processor parameters LM=8, RM=78, TM=2, BM=2)
                      Taken from KeelyNet BBS (214) 324-3501
                           Sponsored by Vangard Sciences
                                    PO BOX 1031
                                Mesquite, TX 75150

                                  August 2, 1990

                       Courtesy of NASA BBS at 205 895-0028

                                   CROP DUSTING

          The wasteful drift of aerial crop dusting chemicals beyond target
       areas has long  been  a  matter  that  was heightening environmental
       concerns and was  becoming ever more  expensive  as  chemical  costs
       increase.

          A decade-long  program  of  research  on  agricultural  aviation,
       conducted by Langley  Research  Center,  focused  on  investigations
       designed to help the aerial crop dusting and spraying industry solve
       this major problem of drift.

          Langley's investigations involved  studies  of  aircraft wake and
       how the wake affects chemical dispersal patterns;  the  aim  was  to
       identify modifications to  airplanes  or  to  dispersal equipment to
       allow more accurate, more uniform spray patterns.

          From this research came an important  aid  to  aerial applicators
       and equipment designers,   a  computer  code  called   AGDISP   (for
       Agricultural Dispersal) that   allows   accurate   spray  and  drift
       predictions.  Jointly funded by NASA  and  the Forest Service of the
       Department of Agriculture,  AGDISP  was  written   for   Langley  by
       Continuum Dynamics, Inc., Princeton, New Jersey.

          Continuum Dynamics has since advanced the technology another step
       by developing, with  company funds, a commercially available version
       of the code for use on a personal  computer  by an operator who need
       not have any prior computer experience.

          Called SWA-H  (Spray  Width for Airplanes Plus Helicopters),  the
       software models the  turbulent  flow behind an agricultural aircraft
       and predicts the motion of materials  released  from  spray nozzles,
       taking into consideration airplane, atmospheric, material and nozzle
       characteristics.

          The printer   output   provides  detailed  information   on   the
       concentrations and motions of the spray cloud, including an estimate
       of drift.  The  user may then change certain factors---such as spray
       height or nozzle position---to achieve the desired swath width and
       application concentration while minimizing drift.

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       If you have comments or other information relating to such topics as
       this paper covers,  please upload to KeelyNet or send to the Vangard
       Sciences address as listed on the  first  page.   Thank you for your
       consideration, interest and support.

           Jerry W. Decker.........Ron Barker...........Chuck Henderson
                             Vangard Sciences/KeelyNet




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