[TowerTalk] Re: Projected Area (something rotten in

[Guy L. Olinger]

Many thanks all for continuing to pursue this in an open forum. Please
keep it up. I am starting to get a little bit of a grip on things.
Also am scheduling a free day to get over to the library at NC State
with my calculator, etc. The quotations of source books will be very
useful.

A question below in quoted text.

Again, thanks, & 73,

Guy
k2av@qsl.net


On Mon, 24 Aug 1998  7:30 -0800, "Hank Lonberg"
<Hank.Lonberg@harrisgrp.com> wrote:

>
>     
>
>Bill:
>
>The equation used in TIA/EIA 222-F which is the latest revision and the UBC 
>defines the basic wind speed stagnation pressure (a datum) value as:
>
>        Qs = 0.00256V*V
>
>        This is base on Bernoulli's equation which can be arrainged to give
>
>        Qs=1/2*RHOair*V*V8
>
>                Density(air) at 59 deg F and 29.92 in Hg is 0.0765 lbs/cf
>                Rho=Density/g
>                RHOair=.0765/32.2
>
>        To express in MPH
>
>        Qs= 1/2(.0765/32.2)(1/3600)*(1/3600)(5280/1)*(5280/1)*V*V
>
>        Qs= 0.00256*V*V

As temperature goes up the load would decrease. Hurricanes tend to be
70-75 degree events, very warm. Tornados and Thunderstorm microbursts
seem to be very cool, 45 degrees or 50? 

Another event common enough, 30-40 mph with rain, 50-60 degrees. 

Also in other parts, 30-40 mph with temps below freezing, say 20
degrees F. 

What kind of variations would these place in the final figure. What
would be the worst value of these?

>
>
>I don't know of any safety factor in this derivation
>
>Hope this helps
>
>73
>
>Hank /  KR7X
>

Guy L. Olinger
k2av@qsl.net
Apex, NC, USA

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