Little things can make a difference but sometimes not in the way expected.
Yesterday afternoon I was headed back into the house from the shop when
I noticed a pole standing in the yard about 10' from the tower. Just a
rod about 8 to 10' tall and pretty much vertical. But...there shouldn't
have been anything there...
It was two pieces of Aluminum tubing telescoped together.
What the thing had been, was the boom truss for the 7L C3i 6-meter Yagi.
It couldn't have weighed more than a few ounces. It had apparently
fallen straight down, with the large end leading.
The surprise came when I pulled it out of the ground and I do mean pull.
That thing had taken a core sample out of my yard over a foot deep. I
don't know what it would have done to the garage roof had the antenna
been pointed the other way, but I'd sure have hated to have been under
it. Then again imagine the 30 to nearly 60 MPH winds we'd had the
previous day urging the thing along. Apparently those winds weakened it
enough that the few gusts we had yesterday finished the job.
OTOH I still have trouble comprehending something with such little mass
hitting with so much force. Apparently falling with the tubes aligned
vertically there was very little resistance from the air to prevent
acceleration and from 115 feet it must have been moving right along.
Note V= Velocity in ft per second, a = acceleration (32'/s^2), t=time
in seconds, and d= distance in feet.
OR if I did my math right where distance = a*t and t^2 = (d*0.5)/a or
s^2 then (d*0.5)/32'/s/s or s = (d*0.5)/32
All that works out to roughly(averaged) 1.8s falling time which equates
to a speed of 57.6 f/s which is hauling.
I hope I got the math right...at least the units cancel<:-)) As a ball
park figure that's about 30 MPH. If you want to be more precise,
multiple 57.6 by 3600 seconds in an hour and divide by 5280 feet per
mile. I did all the rest long hand as my calculator is out in the shop.
<:-))
The point of all this, is that piece of loose, light weight Aluminum we
don't think much about, is dangerous and could do some serious damage
under the right conditions and target.
73
Roger (K8RI)
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