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## Wind area of mast.

 To: Wind area of mast. fmart@tinet.tinet.fut (EA3KU Fernando Martinez) Fri, 06 Sep 1996 11:34:57 +0200
 ```> > I want to calculate the effective wind area of > a 2" diameter mast that is 72" long. > > Therefore 72" X 2" = 144 sq.in = 1 sq.ft. > > The calculation above would be accurate if the > mast were square. But because it's round > isn't there a constant I neet to multiply the > result by. > > If anyone know this constant please let me know > and also tell me its source such as EIA-222, etc. > > Thanks. > > Gene > WD8OZL Hello Gene. Before to continue, let excuse me for my but english. I order to anwer your question, you must know that the item you are looking is named ( on spanish Coeficiente eolico de forma ) Eolic Shape Coeficient (????? in english . Cilynder shape its vary from 0.6 to 0.8 ( depending on his surface texture ), 0.6 for a very smooth surface ( our case ) and 0.8 for a very rough surface. On any case, if your are calcutating the total wind presure over and antenna system, I think that best rule is to condider the worse case, its consider the mast as square shape. It will give you a goog safety factor, then apply the resultant repressure at the top of the mast, then calculating the 'flector moment' over join point beetween the mast and the tower ( if you are using a tower ). This, dont increase a lot the total results and you will have a very good safety factor. Fernando. EA3KU. ```
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