Pounds of pull on Tower

[Shadow]

I need someone thats good at math to help figure out some pounds of pull to raise a tower with generator attached.

   Heres what I have, and plan to do.

 4 legged tower 48 feet 6 inches tall

 weight of tower- 950 lbs total

  weight of generator complete- 500 lbs

 Not sure what all will be relevant here to figure this out but I'll try to include everything.

 Base from leg to leg 10 feet 6 inches.

  Length of gin poles 18 or 20 feet (ones shown in photos are 16 feet but I may have to go longer with wider tower)

 Cables will run from 6 inches down from top to gin poles and from 24 foot mark to gin poles to pull from 3 points.

  Gin poles are about 80 degree angle to tower when it is upright.

   Now I need to know how much weight each cable is pulling, and How much total weight I'll be lifting, to size my cables and winch accordingly.

    I have raised and lowered the tower pictured numerous times with my 14' dual rotor on , its a bit of a pull to start with but about a third of the way up the weight seems to shift down to the legs more to lighten the pull.

     But thats 3 legs with a light turbine, Now I'm dealing 4 legs with a 500 lb turbine. (440 actual lbs but I'm figuring in a little extra)

[defed]

i have seen the formulas somewhere, but can't remember where.

i also have a 3 legged tower that i hope to be able to tilt.  it is a rohn free standing, 3 sections of 20'.  will only use 2 sections to begin with and possibly a 10' extension pole off the top.  the base of mine has 2" heavy wall pipe (5' spread), while the next section is 1 7/16" solid rod.  each section weighs close to 500 lbs.

can you tell me what the tower being raised in the photo is made of?  my worst fear is the pipe legs buckling, but the base section is pretty stout.  i plan to do it similar to yours w/ an A frame gin pole.

[cardamon]

first you have to know where the center of mass of gravity of the whole mess is, I calculate it at 34 feet up from the base, assuming the tower's mass is uniformly distributed which it is not, but this will cheat the answer toward the heavier direction.  A single cable attached from the top of the gin pole to the CG would make an angle of about 30 degrees which would result in twice the force as the weight of the whole mess, or about 3000 pounds.  That would also be your pulling force if you were pulling at 90 degrees to the gin pole which you probably are not unless the ground slopes up a lot.  To compensate for that, divide the 3000 pounds by the cosine of the angle of elevation from horizontal of the winch cable.  Remember this is all breaking strength not working strength.  I did that quick, someone should double check me....

[SparWeb]

Shadow,

If you can just fill out this short survey....  ;-)

I wrote an analysis for my winch installation and it's easy now to just put your numbers into the same routines.

Send me an e-mail.  I'd have to ask a few more questions.