any engineers out there willing to give input

[Steve Barone]

Hello, I have been reading this forum on and off for a while now but never really posted to it so here goes I hope I can make it work. I have been looking at turbines for about three years now and have decided that the only one that will really payoff for me is the Prairie Turbines Breezy 5.5, the only thing that I don't like about the installation is the guyed tower, I have to much 4 wheeler traffic in my yard for that. I would really like to build a tilt down tower but have not been able to get any input from anybody as to what size pipe I can use to support the weight of the turbine and the wind force applied to the 20' swept area. I have the stationary legs in the form of 8"X3/8" I Beam the height of my tower is about 48' (to close to an airport to go any taller, 60' to the top of the swept area has been approved) the attached is a drawing of the tower I am trying to build any advise would be greatly appreciated, thanks STEVE

918

[Stewart Corman]

Steve
A few observations/comments:
Having seen Mario's 65ft free standing pipe tower, which is only supporting a 60 pound turbine of 7 ft diameter:
http://www.greenpowertalk.org/showpost.php?p=1049&postcount=4

The 65 ft. it's a tilting pipe tower constructed out of three 6 in. diameter well casing 2 of the pipes are 10 ft. in concrete and 20 ft. up to the pivoting point, the 3rd 6 in. pipe is hinged 20 ft. down and 10 ft. up, next pipe is 30 ft. long with 10 ft. inside the 6 in. and above that is 4 in. and a short 2 1/2 in. to fit the turbine hub for a total of 65 ft. of high.Your diagram shows a 48 foot pipe "beam", but that isn't in one piece.
Mario used a 6inch at the bottom section and stepped down as he went up to the top
If you can procure a 30ft/6 inch with 1/4" wall, then a 30ft/5in for the top section, then your pivot could be a 1" solid billet drilled through both pipe section.

the added advantage is that the heavier pipe at the bottom adds counter balance weight to offset the turbine weight at top end as well as extra pipe length above the pivot.

Mario then inserted a steel slug into the bottom so that his tower was almost balanced. My wife was able to crank it up and down with little effort.

Knowing the weights of the pipe/turbine and the pivot point, you can do a simple calculation of the tension in the winch cable ...you need enough counterbalance to keep it at a few hundred pounds.

I still recommend a single spreader for lower/raising, whereby the 1000 pounds hanging 27 feet out when horizontal, is applying quite a stress on the pipe causing it to bend.
A shear-moment diagram is used and there are online tools that can do the calculation for you
KISS: presume it is a 48ft/5in pipe and yours will be beefier.

Stew Corman from sunny Endicott