[TowerTalk] Wind Surface Area estimates

[k6ye at q.com]

Gary,

You may want to go with 11.0 figure. You need to factor in "moment of force" (aka torque). This may help you sleep better on very gusty days. Good luck in your choice.

Semper Fi,

Tommy - K6YE
DX IS and CW RULES


----- Original Message -----
From: Gary Slagel <gdslagel at yahoo.com>
To: TowerTalk <towertalk at contesting.com>
Sent: Fri, 09 Mar 2012 09:50:36 -0500 (EST)
Subject: [TowerTalk] Wind Surface Area estimates

Hi guys... more questions!

I'm thinking looking at putting an A4S and and some kind of 40M yagi on the same mast.  I plan to rotate the 40M yagi 90 deg from the A4S to minimize interaction.  I'm thinking somewhere in the future I may even add another A4S somewhere down the tower a ways.   

The A4S has an advertised windload of 5.5 sq ft.  The 40M yagis around the same 5.5 sq ft.  But, I'm thinking the 40M yagi is 5.5 sq ft looking at it from the front.  Looking at the side of the 40M yagi (2" boom and 22.6 ft) I'd guess more like 2.5 sq ft.  Same with the A4S from the side.... a 2" 18' boom should be around 2 sq ft.  So... total windload with the yagi's arranged 90 deg from each other should be 5.5 + 2 = 7.5 sq ft from one side and 5.5 + 2.5 = 8 sq ft from the other side.

Is my logic ok there?

Thanks for your opinions!
 
Gary Slagel
Ace Hardware
207 So Chicago
Hot Springs, SD 57747
(605) 745-5173
KT0A    
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