Doug writes:
>I am willing to give the 'NO Group' a bit more time to present
> a case before coming to a conclusion. No matter how flat a
> pancake is - there are still two sides.
Side #1: Do it unless there's proof that it's unwise.
Side #2: Don't do it unless there's proof that it's OK.
Salient examples of this dilemma where side #1 wins:
Jan. 28, 1986; Challenger; seven lost
Feb. 1, 2003; Columbia; seven lost
> What do you do in the absence of your points 1 and 2? No
> manufacturer direction and no engineering analysis. I suppose
> one choice would be to not put up that tower. The other choice
> is to find out what experience others have had.
Experience: "We've flown that configuration umpteen times without a
failure" - see examples above.
> I think the experience factor should have more weighting than
> either points 1 or 2. Someone here once said "experiment trumps
> theory". If I have sensibly guyed self-supporting Delhi towers
> for 35 years without a single failure, I have enough data to
> recommend guying in my area.
1. Thirty-five years without a failure is not an experiment; just a log. See
my response to the previous paragraph.
2. Your experience is not an appropriate example, since Delhi does recommend
guying. Furthermore, while you "have enough data to recommend guying in my
area", that experience is not broadly applicable without Delhi's
recommendation, nor is it applicable to a tower from another manufacturer.
> "A good plan today is better than a perfect plan tomorrow".
Yes; in some situations a guess is appropriate. Management 101: "Ready,
fire, aim".
In other situations, mine for example, the risk is not worth the potential
benefit. I have done the "simplified analysis" and am barely comfortable
with the safety margins (different tower; different results) in a guyed
configuration. Since the benefit is indeterminate, mine will remain unguyed.
If I had a Delphi tower, I would consider guying a viable option. To extend
Delphi's specs to any other tower is unwise, I think.
This thread has been interesting and healthy because it illustrates that
technical issues can easily become philosophical ones, subject to judgement
calls; and that "Hard Science" is an oxymoron!
Chuck, N4NM
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|