Tower stub length?

[Dennisd]

I am getting close to finishing a standard 10', and am starting to build the tower. The question I have is what length to use for the 2" stub? I am planning on using a 2 1/2 inch sched 40 pipe on top of a a 3" pipe, with a 2" stub sticking out of the top. Do most use a 13" (above the 2 1/2), with the top guys attached 4' below that (total 5' below top for blade clearance) or with a 5' stub so that the top guys are at the joint between the pipes?

[Boss]

I had made ours at six feet, but combined with other mods I made it bent so I beefed it up a little
honestly, I think the two inch pipe I used would have worked had I not lengthened the blades by six inches. I did see the stub flex in high winds. The furling always worked before I did that extension. Live and learn, that is a big part of this hobby
Anyway, shorter the better

[fabricator]

I'd say three feet max, you don't want the turbine putting a lot of leverage on the stub, the longer the lever the more stress you will have at the tower/stub connection.

[TomW]

Boss;

Gotta say I love your low tech tower ground support. Local materials, recycles and provides an elevated,  soft landing pad. 

Tom

[prasadbodas2000]

minimum possible unsupported length (i.e. free length above the highest rope attachments) is the better it is. In case of a 10 footer, based on the expected angle of ropes and the blade positioning/room in front of the tower a free length in range of 4 to 5 feet should do good. Attention to be paid to the flexing of blades due to wind force and in any case they must not hit the ropes....

All the best.

[luv2weld]

In case you haven't seen this yet.


http://fieldlines.com/board/index.php/topic,129803.0.html

Beware of using a long stub.

Ralph

[DanB]

I would keep the stub at the top about 13".  and keep the top guy wires just below the blade tips.