Cable Strength?

I agree, about a half ton winch and cable would be required...

You have correctly identified additional external forces that need to be considered. In order to calculate what is required you need to consult an "expert". That "expert" can calculate what you need to do, including the connections required, what kind of deadman, angles, etc. you will need to support the winch, etc.. It is really not that simple. If it was me, I would look at the application and install a real overkill of a solution (because I am not an "expert", although I consider myself a "practical" professional engineer, and would make it "look" good). For the additional initial cost it is always "better safe that sorry".

I'm coming up with 120 x √2 ≈ 169.7 lb.

I get the angles at 45°, 45°, and 90° at the base, that would be force times 1.41 or 169.2 lbs...but with a 5 to 1 safety margin, that would be 846 lbs...

https://www.engineeringtoolbox.com/rope-angle-tension-increase-d_1507.html

Thanks, you're right. Somehow, 120 changed to 200 in the brain fog...

Cable is cheap,towers are not.Don't design for the minimum on this project.

1000 lb cable is still very cheap,and gives plenty of safety margin.

Buy a high-ratio cable winch,and you can probably operate it with a hand drill.

Do not pinch pennies on the foundation and anchorage for the tower.

Wind and leverage of the tower(20 to 1) can have an amazing amount of torque at the bottom of the tower.

Good luck!

Thanks everyone!

NSS-

Beside the cable strength, you also need to consider the total weight of the cable together with all the hardware that will be required in rigging your tower.

. . . . and don't forget your pulley anchorage also needs to be robust.

Good Answer!

Others have posted about cost of rope and cost of tower. What really matters here is who is hurt or killed by the falling, bouncing and flying sharp parts as the tower comes down. Unexpected failures often fail in unexpected ways. When the falling tower hits your parked car the momentum of the top of the tower causes the foundation you "cheaped" on to break loose and now you have shrapnel flying in all directions. As stated by jhhassociates and others, EVERY component in the system needs a good safety factor.

While you can go into the mathematics as others have done it seems pointless to me.

Being an amateur myself and having installed many of these tilt over designs for myself and others I believe in the KISS principle. Just go out and buy a boat hand winch, the cost of these is below $100 for a 3000Kg rating. Choose a two speed if you like for it will make it even quicker

Forget the mathematics unless you are set the example in a school paper and want marks. Mount the winch at a comfortable height. The pulley strength and attachment are more critical than looking for the minimum rope size.

Why use the attachment at such a height, typically a 100mmx100mm RHS beam around 3m high cemented beside the tower into the foundation using a 50mm pulley with a 400/500 Kg rating suffices to raise such a tower with a 6m beam for 6m coms.

I designed and installed this decorative windmill in a local community garden a year and a half ago. The wood mast is scissor-hinged about five feet from the base. Put it up using a come-a-along with a 1/4" stainless wire rope. Last Saturday had a storm here in S. Ontario with windspeeds over 100 mph. Trees down everywhere. Power restored just a few hours ago. The windmill was unscathed. When building, drilled long length-wise holes at the top and drove in 4 threaded rods coated with construction adhesive. That detail probably saved it. The flapping wing mechanism uses salvaged parts from an eliptical exercise machine - very robust. Wings must have been flapping like a bumblebee during the storm. Thought this project would interest others here.