In a message dated 96-09-05 11:40:14 EDT, you write:
>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
Hi, Gene --
You're just about there. The round-member multiplier, or drag
coefficient, is 0.67. It is used by Dave Leeson, W6QHS, in his book
"Physical Design of Yagi Antennas", page 7-6.
The EIA/TIA-222-F uses a 'reduction factor' of .51e(squared) + .57
where e is the solidity ratio. They also have an appurtenance force
coefficient for a cylindrical appurtenance of 0.8 for an aspect ratio <7.
You should investigate it further to look at the definitions and
applicability to your question. This info is covered on pages 3-8
73, Steve K7LXC
TOWER TECH -- professional tower supplies and services for amateurs