[TowerTalk] Falling derrick

[Grant Saviers]

Where and how you attach to the HDBX would be the starting point.  A bit 
tricky given its design.  2/3 the way up might be ok so it doesn't 
buckle, but that is a guess.  It's a trade off of tension buckling vs 
bending buckling and how to distribute the connection load to the angle 
members.  Better ask Rohn.

Grant KZ1W

On 3/20/2021 07:50, John Simmons wrote:
> I'm planning a tower installation for the summer. It is an HDBX, 
> sections 8-4 (40 feet) with the hinged base. A 70 pound yagi and a 
> Tailtwister will be at the top with a very short mast. I want to build a 
> falling derrick system for it.
> 
> I'm searching for answers to a couple questions:
> 
>   * How long should the lever be?
>   * How much pulling force will I need to raise the tower? I realize
>     that the force will be maximum when the tower just comes off the 
> ground.
> 
> I found this reference:
> https://comtech.ru/en/production/towers/tower-accessories/ct-s3ts/ct-s3ts-falling-derrick-tilt-up-method/ 
> 
> 
> I'm neither good at physics nor math above algebra.
> 
> Comments?
> 
>