[TowerTalk] FW: Opposing boom to mast plates?

[maflukey at gmail.com]

Wind drag over tubes essentially acts perpendicular to the axis of the tubes, thereby transferring the drag force axially to the boom, which creates a torque moment about the mast because of the short moment arm (distance from centerline of boom to mast - usually a few inches).    Example:  50 lbs total element drag force x 2 inches = 100 inch pounds, or about 8 ft lbs of torque.    Typically negligible in the big scheme of things...

Matt
KM5VI



-----Original Message-----
From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of Chuck Dietz
Sent: Sunday, September 17, 2023 7:22 PM
To: K7LXC at aol.com
Cc: dcharing at gmail.com; stevewalter90 at gmail.com; towertalk at contesting.com
Subject: Re: [TowerTalk] Opposing boom to mast plates?

Well my masts are very heavy. Weight of the antennas is not a real factor.
And saying someone is not an engineer doesn’t help either.
I believe It is a fact that the wind forces on Yagi antennas pointing in the same direction are transmitted to the mast in the exact same manner regardless of which side of the mast they are clamped to. It is a fallacy to think that they would exert force in the opposite directions and cancel.

Chuck W5PR

On Sun, Sep 17, 2023 at 4:03 PM <k7lxc at aol.com> wrote:

> >  They were minimizing eccentric loads off the vertical centerline by
> putting one on either side. It won't do anything for reducing turning 
> torque or wind loading, of course.
>
>     Looks like you're not a Professional Engineer.
>
> Cheers,
> Steve      K7LXC
> TOWER TECH
>
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