Tilt tower question

[SmoggyTurnip]

I am thinking about building a tilt up tower. 100 ft high.  10" steel tubing, .134 wall thickness. 60ft gin pole.

One thing I am wondering about is during the raising orf the tower at some point

the weight of the gin pole should be enough to have the tower want to continue

going up on its own.  This would make the cable that is pulling up the tower go

slack and I really don't know what would happen after that.

Also when tilting the tower down how is the weight of the ginpole overcome in the

begining.  It seems to me that the tower would have to be pulled by something untill

the weight of the ginpole is overcome.  How is this usually handled.

Thanks in advance.

.

[DanB]

60' is a long gin pole!

Yes - that was one of my worries.  First time we raised it I had 4 people pulling on the North (opposite gin pole) guy wires and it was pretty easy though it got a little spooky because they had trouble keeping the winch cable tight.  The angle at which the gin pole outweighs the tower gets less as we add weight to the tower top.

Last friday I bought 250' of good nylon rope and put a pully on the North side of the tower.  One of the the rope can tie off to a tree, and then one or two people can easily pull it over (or fight the winch as it goes up).  This was the 'easy solution' - and it keeps everyone involved well away from the tower while raising and lowering.

I had thought of having a 'weight' that start getting lifted at the moment when the gin pole starts to outweigh the tower, that would also be fairly easy - but as things are now it seems good and raising/lowering my tower is possible with 2 folks and quite easy with 3.

Yours will be a lot heavier than mine though.

[jmk]

 I have a 600 pound gin pole. When it gets to the ballance point I have a cable hooked to a winch on the other side. I just simply change sides and crank the gin pole down as it makes the tower go up. To lower the tower I just crank the winch in and then switch when it gets to the ballence point. It works great with two people, and I've done it several times by myself. You just have to go back and forth and when you get to the ballence point you end up going back and forth a few extra times because you dont want to let to much cable out on the gin pole side. The ballace poin will travel some before it takes to the other side.  

[Countryboy]

There is no need to make it more difficult than it is.

You are describing a pivot that is perfectly centered on the tower tube.  Offset the pivot a little towards the gin pole.  Have it almost balanced, but imbalanced enough that the tower would fall if it were not for the guy wires.  That way, the tower will always apply a little tension on the winch cable/guy wire.  

When vertical, the vast majority of the weight will be on the tower base.  The force on one guy wire will be a minimal amount higher than the force on the other guys.

[SmoggyTurnip]

I am not sure what you mean here.

I am thinking that if the pivot point were not directly

under the tower that the bottom of the tower would want

to go into the ground when tilting down.

.

[SparWeb]

There are detailed instructions on the Bergey website that tell you how to raise their towers.  Though not as tall as yours, they're pretty heavy and the same principles will apply.  You don't have to buy a Bergey to learn a lot from them!

Their manual suggests that once the tower has been raised to the balance point, but there's still tension in the lift cable, a person should go to the gin pole and lower it by hand to the ground.

Hmmm... not sure this would work if the height, hence the forces & weights, are doubled.  Going with the back winch sounds like the better plan.

Isn't this your first tower Smoggy?  This may have been hashed out in another thread, but could your mill do almost as well on a 50'?

[SmoggyTurnip]

Yes this is my first tower.

I don't see how any mill could do as well at 50 ft

as it would at 100 ft.  But maybe it is too much for

a tilt up.  Still thinking about it.

.

[SparWeb]

Another thought... There is a point where tilt-up towers are not practical for amateur users.  Dan seems to have a dozen people hauling on his 100 footer, and the whole operation is clearly not for the faint of heart.

[SmoggyTurnip]

Actually I would not describe myself as faint of heart

But Dan said in his post that he had 2 or 3 people pulling

not dozens.

.

[SparWeb]

Oops, I was counting the kids and furry forum editors...

Good luck.

[Flux]

You always need a back rope and some means of tension control. How much tension it has in it as you approach vertical depends on whether the gin pole is attached to the tower or has its own pivot..

Flux

[Countryboy]

You would need to elevate the pivot enough the base of the tower didn't try digging a hole.  Or, you could just pre-dig the hole.

[SmoggyTurnip]

What would carry the weight of the tower?

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