[TowerTalk] Heights pre-1995 Aluminum Tower

[Richard (Rick) Karlquist]

I have a spreadsheet that calculates wind loads and stress on the older 
Heights sections.  If anyone would like a copy, email me.  The thing
that becomes apparent is that if you want to tilt over the older
sections with the Heights screw drive, you tend to be more limited
by dead weight than wind loading.  The workaround for this (besides
climbing and installing everything while in the vertical position)
is to instead use a falling derrick method to tilt it up.

Rick N6RK

On 9/29/2012 11:13 AM, jeryb77 wrote:
> Hans and Ron,
> Thank you for your replies.
> I came into possession of this tower somewhere around 1991 so have no real idea of it's date of manufacture.
> Heights did move from Michigan to Florida.
> When conversing with Heights, they will reference pre-1995 towers because that is the cutoff when many things were changed in the design.
> They claim that they have no data available for wind loads etc for the earlier towers, so I am almost certain that it just boils down to a liability issue.
>
> I am trying to determine a safe rating is for the tower that I have, and whether or not it was added to compared to what (standard) configurations were available. ( I think where this tower was added to, it should have been stepped more instead of adding an additional straight section to extend it's total height)
>
> What I actually have is a total of 48ft, it is a tapered free standing tower which I beleive was used with a hinged base (not foldover).
> The biggest difference between pre-1995 and the current offerings is the wall thickness and in some cases the dia. of the legs.
> Although I am unsure, possibly the earlier sections were 6063 aluminum whereas now they state that they use 6061.
>
> The sections that I have are as follows:
>
> All sections are 1" dia. legs with the exception of the bottom 18" section which is 1.25" (The new design 18" sections are now 1.31" or 1.72")
>
> 1" legs have a wall thickness of 0.065" (new design wall thickness is now 0.125")
> 1.25" legs have a wall thickness of 0.085". (new design for 1.31" legs now have a wall thickness of 0.140")
> The cross bracing on the 11" and 14" sections is 3/8" dia aluminum rod, and the 18" section has 7/16" dia.
> All sections are 8ft in length.
>
> 11" top section
> 14" taper
> 14" straight
> 14" straight
> 14" straight
> 18" taper
>
> I think that one of the 14" straight sections was added and it was probably suppose to be a 40' tower instead of 48'
> Two of the 14" straight sections need to be either repaired or replaced as they have split where water has frozen in one leg of each of them. Upon further inspection, I see a manufacturing defect where there is a definate obstruction in each of those legs that did not allow the water to drain through the legs. It appears that it might have been caused by a welding burn thru when the crossbracing was being welded (i.e the obstruction is solid aluminum)
>
> Ron...if you can make copies of what you think would cover what I have, I would appreciate them.
>
> Thank you,
>
> Jerry
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