[TowerTalk] 80m vertical: reality check

[Yo3ctk]

I am trying to design an 80m lambda/4 vertical for a 4-square. My plan is to use 6 ft sections of AL tubing, 0.058" wall, as advertised on Texas Tower website:
http://www.texastowers.com/aluminum.htm

Starting with biggest O.D of 2.125", twelve (12) more 6 ft sections of progressively smaller O.D. will be telescoping with 1 ft overlap at each joint. Joints will be fastened with AL rivets. The entire vertical will have an (adjustable) height of 66 ft (20m) and a total weight of about 22 pounds (10 kg).

Unfortunately I have no expertise in calculating if such a structure is mechanically sound, hence following questions for the experts on the list:

1. Is the vertical expected to break at the lower joints in stiff winds (say no more than 65mi/100km/h)?
2. Must the vertical be guyed? Where?
3. Is it feasible to raise the vertical from the ground, by fixing the largest section to the base and telescoping sections starting with the smallest diameter, and riveting as we go?

Thank you all for any comment.

73 de Mike, YO3CTK
YR7M stationmaster