Charles:
Sorry to learn of your Trylon problems. Of course, you know it was overloaded.
Based on your estimate that the top was 12 inches across you probably have a
Titan T-300-80
http://www.trylon.com/lightdutytowers/pdfs/80ft%20Titan%20Profiles.pdf . If you
look at the specs
http://www.championradio.com/T300-80-Trylon-Self-Support-Tower.52 it's really a
light duty tower. At 85 mph winds it is rated to support only 6 sqft of anenna,
and that's within two feet of the top shelf. My T-500-64 Trylon holds only a
Skyhawk tribander, D40 dipole and GP-15 V?UHF vertical. I calculated that I
could add a long-boom VHF and UHF Yagi and that's it.
The design of Titan towers virtually guarantees that they will fold in half as
you experienced. The upper sections' legs and cross bracing are made from
thinner gauge steel than the lower sections. If you use Trylon's design tool
http://www.trylon.com/lightdutytowers/towercalc.asp you will see that the mid
sections have the least safety margin. They will fail first upon overloading.
73 de
Gene Smar AD3F
On 01/31/13, Charles Harpole<k4vud@hotmail.com> wrote:
I put up a used Trylon self supporting 80ft tower that I do not have the Model
number of. It was about 36 inches from leg to leg at the base and tapered to
about 12 inches at the top, each section nesting inside the next larger one,
forming one shipping package. The cross members were angle iron galv. steel and
the uprunning three legs were U channel, not tubular. It was loaded, or over
loaded, with one each 20m 5 el, 15m 5el, and 10m 5el HyGain yagi in the HyGain
Christmas Tree pattern with a very heavy (I could not lift it) 23ft chrom molly
mast, six feet down inside the tower with two thrust bearings and the T2X rotor
below. All the bolts throughout were replaced with new galv correct sized bolts
and it had no rust. Mounted in a six by six solid concrete base. Four years
after installation, I noticed two bowed cross members next to each other on
horiz. at about the 40ft level and one bowed at about the 70ft level, all of
which were replaced with similar steel angle iro
n, bolted as the original. After seven and a half years, a very powerful
straight line wind with near horiz rain for about five minutes caused the tower
to fold over at about the 40 foot point, the lower sections standing ok, and
only the one bent section destroyed. All yagi sustained total loss of front
half of each, with the ten getting more bending. Rotor and mast were ok. The
break point showed about 30 degrees of twisting. Seventy feet away is a 70ft US
Tower crank up free standing with a two el 40m quad and inside elements for 30
17 12, made by Cubex, T2X rotor. This tower was cranked to full height and
sustained no damage. My conclusion is that the Trylon was very loaded and that
its weakness was to twisting forces, which it hinted at earlier and showed
conclusively upon it folding over. Because it failed, I also concluded that "it
was high enough." Replaced it all this week with new tower and rebuilt yagis.
73,
Charles Harpole
k4vud@hotmail.com PS... if you have never dis assembled a T2X rotor, be
POSITIVE to read hams reports of how to do that prior to opening the bell.
Those in the know are now smiling.
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