Towertalkians:
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
