[TowerTalk] Stub mast strengthening

[Gene Fuller]

Hi Steve -

I am successfully using that type of construction on elements in my Log 
Periodic. I have as many as 3 or 4 layer of tubing and as a quick "swag" at 
strength I just added the resistance to bending moment of each additional 
layer. The longest elements I have are about 46 feet. I designed it for 100 
mph wind with 1/4" of ice. It's been up for about 12 years, with wind of at 
least 85 mph with no problems. Two primary factors led me to this design - 
First of all, I had lots of old tubing that fit the need. Second,  I was 
able to get to the desired mending moment resistance and keep the max O.D. 
down to 1 5/8",  thus keeping the wind resistance and area for ice 
accumulation to a minimum.
Bottom line - I would vote in favor of using the insert if you think you 
need the extra strength.
Gene / W2LU



----- Original Message ----- 
From: "GW4BLE" <steve.gw4ble at btconnect.com>
To: <towertalk at contesting.com>
Sent: Tuesday, April 16, 2013 11:31 AM
Subject: [TowerTalk] Stub mast strengthening


>I have a question concerning 'sleeving' (can't think of a better way to 
>describe it) -  I have a 16' x 2.5" OD thick-wall aluminium tube that will 
>be used as a stub mast, would inserting 6' x 2" OD thick-wall aluminium 
>tube into the bottom of the tube add to its' 'strength' in any way or would 
>it just add unnecessary weight?
> Sliding it in makes quite a snug fit, but not exactly 'tight'
>
> Steve
> GW4BLE
>
> Sent from my iPhone 4S
>
>
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