Hi Rick,
Like I said, “I don’t know how long is required....”. I used a hand crank to
crank up a very tall crankup tower many years ago at KR2N – it may have been a
TX472 but I don’t recall. It was an agonizingly slow process – it was
interminable. I didn’t time it. It’s just a painful memory now. ;-)
I used a round number of 1’ per second to crank up with an electric winch even
though the first section is not cranked up. I had no idea that the electric
winch really operates about 1/15 of that speed!
20 Minutes? The tower would have no chance to be cranked down in response to a
significant wind or weather risk.
Bob KQ2M
From: Richard (Rick) Karlquist
Sent: Tuesday, July 09, 2019 2:26 PM
To: Bob Shohet, KQ2M ; Wilson Lamb ; undefined
Subject: Re: [TowerTalk] Fall Zones
On 7/9/2019 7:39 AM, Bob Shohet, KQ2M wrote:
> I don’t know how long is required to crank down at 89’ crank-up at full
> extension but I would suspect that it is at least 90 seconds.
>
90 seconds????
My 106 foot crank up takes at least 20 MINUTES to crank down.
A lot of "stuff" can happen in that time.
The other issue is that towers without positive pull down
famously hang up in high winds at the worse possible time.
OTOH, reviewing the calcs, it appears that the weak point
in my tower is about 1/2 way up. I am guessing that it
would tend to fold over there and maybe not even hit the
ground at all. Just a guess.
Rick N6RK
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