[TowerTalk] Homebrew Crank-up

Kevin Normoyle knormoyle at surfnetusa.com
Sat Mar 27 14:45:48 PDT 2010


If it's a crankup, I guess there's no guys.

Rohn specs 70mph 0.8 sq ft wind area for 60' of unsupported rohn 55g
Is that 15 lbs/sq ft?

Even if you scale that back to 50mph, how can you get anything at the 
top of 75-5 = 70' of unsupported rohn 55g?
If you guy it, why not leave it up?

Rohn 55g is 18" o.c. 1.5" tubes? That's narrower than the base of all 
72' crankups. (21.125" or so). tubes about the same.
And there's more weight at the top (because no narrowing of sections).

Isn't the real issue that you want a taper schedule to reduce stress 
lower down?

seems like it just can't work?


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