I rest my case!
On Tue, 2 Mar 1999 11:36:36 EST, K7LXC@aol.com wrote:
>
>Greetings, TowerTalkians --
>
> I forwarded a couple of our on-going discussion posts to Tom Schiller,
>N6BT, chief designer at Force 12. Here's his reply:
>
>In a message dated 99-03-02 11:20:55 EST, you write:
>
>> Appreciate the information. I was impressed that apparently nobody has
>> noticed the 70 mph mast torque spec in Force 12 specs for the last several
>> years. I spend a lot of effort to keep this number below 1000 inch pounds.
>> Kurt mentioned that the bulk of the antenna design time is on electrical and
>> not mechanical. In our case, this is not so and never has been. I began the
>"
>> balanced antenna quest" back in 1978. The one I used for several years had a
>> 48' boom 4el 20 with a 2el 40 on it, then a 36' boom 6el 15 above it, with a
>> 36' boom 8el 10 at the top of the mast. I turned all of this with a
>> TailTwister and still have the rotator - never touched it. I wrote my own
>> software to compute the moments and fins, if necessary, which I did not use
>> on my installation.
>> In production designs, I average more than three fold the time on
>> mechanical as electrical design, which is why they take so long. There are
>> many cases where the mechanical drives the electrical. Some of the
>> mechanical issues are more than balance, such as the 30" open area in the C-
>> 31XR. That took me 6 months and was a combination of mechanical and
>> electrical solutions.
>> If you want to share some or all of this, that's all right. Besides the
>> standard 70 mph mast torque spec in the Force 12 brochure, maybe we should
>> add another at 50 mph, or some other velocity. The latest request we have is
>> from Europeans who want the torque in Newtons.
>>
>> 73, Tom, N6BT
>> Force 12, Inc.
73, Guy
--. .-..
Guy L. Olinger
k2av@qsl.net
Apex, NC, USA
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