[TowerTalk] Tower in Tree

Wed May 9 12:08:44 EDT 2007

Now I understand why The Gravity Group, CCI, and other companies who build wooden roller-coasters charge a much higher price when they use Douglas Fir. If they spend the (lots of) extra money up front for Douglas Fir, I know they have to replace sections of the wooden track much less frequently - I just didn't know it was *that* much stronger!
LJ

-----Original Message-----
>From: W7CE <w7ce at curtiss.net>
>Sent: May 9, 2007 8:50 AM
>To: towertalk at contesting.com
>Subject: Re: [TowerTalk] Tower in Tree
>
>
>> >Doug Fir is the strongest North American softwood
>>>species
>>
>> No kidding!   I just looked it up on Matweb.com and the flexural yield
>> strength is listed at 8100psi!
>>
>> The elastic modulus is about a thirtieth that of steel (1000ksi vs.
>> 30,000ksi) , but the cross section of the tree is huge compared to
>> Rohn 25G ...
>>
>
>Exactly!  The tree is much stronger and more flexible than a steel tower.  I 
>can't begin to estimate the wind load that the branches present, but it is 
>probably measured in 100's of sq. ft.
>
>73,
>Clay  W7CE 
>
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