[Towertalk] Strength of fiberglass.

[Don Havlicek]

Solid fiberglass rod is HEAVY .. much heavier than the same
length/diameter of aluminum.
Don
N8DE

WB9UWA Jim Shaffer wrote:
> 
> Hi All,
> 
> I am designing a VHF yagi array and strongly considering using fiberglass
> for the booms. Does anyone have a strength rating for fiberglass that is
> useful
> to the layman? For example, if  10 feet of 1/2" solid rod fiberglass is held
> horizontal,
> how many pounds of weight would cause the end of the rod to deflect 1 foot
> (stiffness rating)?
> Also, and probably of greater importance, because even PVC can be guyed
> if done properly, how much weight at the end of this pole does it take to
> cause
> catastropic failure of the fiberglass (yeild strength)? I have heard stories
> of fiberglass antennas
> bending way over in the wind and recovering fully. This is the sort of low
> windload
> design I have in mind. I have some industry standard numbers for fiberglass,
> but they
> are not something that I can make sense of. The strength rating is something
> like 30,000 PSI.
> 
> 73, Jim Shaffer, WB9UWA.
> 
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