[Top] [All Lists]

[Towertalk] Estimation of yagi windload

To: <>
Subject: [Towertalk] Estimation of yagi windload
From: (jljarvis)
Date: Sat, 6 Jul 2002 10:02:03 -0400

In thinking about Eric's question of windload on a helix,
I came to realize I'd never seen a thorough approach to
windload on a yagi.

*  Does anyone have a reference to a published analysis?

*  Thinking about it:
        * To what degree are 'hidden' elements shadowed by 
        those before them?  It probably depends on windspeed
        and element diameter, as well as spacing.

        *  My guess is, "not at all", in which case, one sums
        the exposed area of the elements and degrades that by
        whatever the flat/round factor is. (.70?)

        *  Further, I suspect that maximum exposed area occurs
        around 45 degrees, where one takes .707 of the exposed
        boom area, plus .707 of the exposed elements area, 
        each multiplied by the flat/round factor, and then summed.

I suspect a search in the IEEE journal might yield something;  
that's my next step.

Has anyone seen reference to wind tunnel studies, in support
of mathematical models/approximations? 

Jim Jarvis/N2EA

<Prev in Thread] Current Thread [Next in Thread>